WO2019163052A1 - Electrically driven vehicle - Google Patents

Electrically driven vehicle Download PDF

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Publication number
WO2019163052A1
WO2019163052A1 PCT/JP2018/006442 JP2018006442W WO2019163052A1 WO 2019163052 A1 WO2019163052 A1 WO 2019163052A1 JP 2018006442 W JP2018006442 W JP 2018006442W WO 2019163052 A1 WO2019163052 A1 WO 2019163052A1
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WO
WIPO (PCT)
Prior art keywords
temperature
speed
vehicle
brake resistor
speed limit
Prior art date
Application number
PCT/JP2018/006442
Other languages
French (fr)
Japanese (ja)
Inventor
菊地　淳
誠司 石田
俊彦 石田
Original Assignee
日立建機株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 日立建機株式会社 filed Critical 日立建機株式会社
Priority to PCT/JP2018/006442 priority Critical patent/WO2019163052A1/en
Priority to JP2020501922A priority patent/JP6864781B2/en
Publication of WO2019163052A1 publication Critical patent/WO2019163052A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

Definitions

  • the present invention relates to an electrically driven vehicle that is driven by an electric motor.
  • An electrically driven vehicle that runs on an electric motor can use a mechanical brake that uses frictional resistance during braking and a power generation brake that consumes regenerative power with a brake resistor.
  • the railway vehicle described in Patent Document 1 sets a section immediately before entering a long downward slope of the operation route as a power generation brake prohibition section.
  • the railcar described in Patent Document 1 previously reduces the temperature of the brake resistor when entering a long downward slope.
  • the railway vehicle described in Patent Document 1 enables continuous use of the power generation brake in a long downward slope section.
  • the present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an electric drive vehicle that can suppress an increase in the temperature of a brake resistor and prevent a power generation brake from being expired. It is in.
  • the present invention generates electric power when regenerative control of the electric motor is performed according to an operation of an electric motor, an inverter that controls the electric motor, a drive wheel that is driven by the electric motor, and a retard pedal.
  • a brake resistor that consumes the electric power as heat; a resistor temperature sensor that acquires the temperature of the brake resistor; a vehicle speed sensor that acquires a vehicle speed; and the inverter that controls the speed of the motor.
  • An electric drive vehicle comprising: a controller; and the controller includes a maximum speed calculation unit that calculates a maximum speed of the vehicle based on a temperature of the brake resistor acquired by the resistor temperature sensor, and the maximum The speed of the electric motor is controlled so as not to exceed the speed.
  • the traveling speed of the vehicle can be limited according to the temperature of the brake resistor, and the usage rate of the mechanical brake can be reduced.
  • FIG. 1 is a front view showing a dump truck according to a first embodiment of the present invention. It is a whole lineblock diagram showing the system for driving of a dump truck. It is a block diagram which shows the structure of the power converter in FIG. It is a block diagram which shows the structure of a traveling apparatus control part. It is a block diagram which shows an accelerator / retard signal calculating device. It is explanatory drawing which shows a 1st limiter. It is explanatory drawing which shows a 2nd limiter. It is a block diagram which shows the speed limitation calculating device by 1st Embodiment. It is explanatory drawing which shows the forward speed limitation calculating part in FIG. It is explanatory drawing which shows the reverse speed restriction
  • the dump truck 1 includes front wheels 8L and 8R, rear wheels 9L and 9R, travel motors 14L and 14R, speed sensors 18L and 18R, inverters 24L and 24R, a brake resistor 25, a resistor temperature sensor 30, and a travel device controller 40. It has.
  • the vehicle body 2 constitutes a frame structure.
  • a vessel 3 loading platform
  • a hoist cylinder 4 as a fulcrum.
  • the cab 5 is provided on the front upper side of the vehicle body 2 and located on the front side of the vessel 3.
  • the cab 5 is disposed on the deck portion 2 ⁇ / b> A which is located on the left side of the vehicle body 2 and becomes a flat floor plate, for example.
  • the cab 5 forms a cab where a driver (operator) of the dump truck 1 gets on and off.
  • the cab 5 is provided with a driver's seat, an engine switch, a shift lever, a steering handle (all not shown), and an accelerator pedal 6 and a retard pedal 7.
  • the accelerator pedal 6 is depressed by an operator when accelerating the vehicle.
  • An accelerator pedal opening sensor 6A is attached to the accelerator pedal 6.
  • the accelerator pedal opening sensor 6A detects the opening degree Pa [%] of the accelerator pedal 6 according to the depression amount.
  • the accelerator pedal opening sensor 6A outputs a signal corresponding to the opening Pa to the traveling device control unit 40.
  • the opening degree Pa is 0% when the accelerator pedal 6 is not operated, and is 100% when the accelerator pedal 6 is fully operated.
  • the retard pedal 7 is depressed by the operator when decelerating the vehicle.
  • a retard pedal opening sensor 7A is attached to the retard pedal 7.
  • the retard pedal opening sensor 7A detects the opening Pr [%] of the retard pedal 7 according to the depression amount.
  • the retard pedal opening sensor 7A outputs a signal corresponding to the opening Pr to the traveling device control unit 40. At this time, the opening degree Pr becomes 0% when the retard pedal 7 is not operated, and becomes 100% when the retard pedal 7 is fully operated.
  • the front wheels 8L and 8R are rotatably provided below the front part of the vehicle body 2.
  • the front wheels 8L and 8R are driven wheels.
  • the front wheel 8L is disposed on the left side of the vehicle body 2.
  • the front wheel 8R is disposed on the right side of the vehicle body 2.
  • These left and right front wheels 8L and 8R are steering wheels that are steered (steered) by the driver.
  • These front wheels 8L and 8R are formed with a tire diameter (outer diameter size) of about 2 to 4 m, for example, similarly to the rear wheels 9L and 9R.
  • the rear wheels 9L and 9R are driving wheels driven by the traveling motors 14L and 14R.
  • the rear wheels 9L and 9R are rotatably provided on the rear side of the vehicle body 2.
  • the rear wheel 9L is disposed on the left side of the vehicle body 2.
  • the rear wheel 9 ⁇ / b> R is disposed on the right side of the vehicle body 2.
  • the engine 10 is disposed below the tiltable vessel 3 (loading platform). Specifically, the engine 10 is provided in the vehicle body 2 at the lower side of the cab 5.
  • the engine 10 is constituted by, for example, a large diesel engine.
  • the engine 10 drives the main generator 12 and the sub-generator 13.
  • the engine 10 drives a hydraulic pump (not shown) and the like.
  • the engine 10 is provided with an engine control device 11 that controls the engine rotation speed.
  • the main generator 12 and the sub-generator 13 are mechanically connected to the engine 10.
  • Main generator 12 is driven by engine 10 to generate three-phase AC power.
  • the sub-generator 13 is also driven by the engine 10. At this time, the generated power of the sub-generator 13 is smaller than the generated power of the main generator 12.
  • the sub-generator 13 is connected to a drive circuit 28 such as a blower 27 and supplies drive power to the blower 27 and the like.
  • the traveling motors 14L and 14R are electric motors.
  • the traveling motors 14L and 14R are provided on the vehicle body 2 via an axle housing (not shown).
  • the travel motor 14L is mechanically connected to the left rear wheel 9L via the speed reduction mechanism 15L and drives the rear wheel 9L.
  • the traveling motor 14R is mechanically connected to the right rear wheel 9R via the speed reduction mechanism 15R and drives the rear wheel 9R.
  • the traveling motors 14L and 14R are rotationally driven by electric power supplied from the main generator 12 via the power converter 21.
  • the traveling motors 14L and 14R are controlled by the power converter 21 and are driven to rotate independently. Based on the control signal from the traveling device control unit 40, the power converter 21 makes the rotational speeds of the left and right rear wheels 9L, 9R the same when the vehicle goes straight, and changes the left and right according to the turning direction when turning. Control such as changing the rotational speeds of the rear wheels 9L and 9R is performed.
  • a mechanical brake 16 is attached to each of the front wheels 8L and 8R and the rear wheels 9L and 9R.
  • the mechanical brake 16 is composed of various brakes that generate a braking force using a mechanical frictional force.
  • the mechanical brake 16 applies a braking force to the front wheels 8L and 8R and the rear wheels 9L and 9R according to the pressure oil supplied from the mechanical brake output device 17.
  • the mechanical brake output device 17 causes the mechanical brake 16 to generate a braking force based on a control signal from the traveling device control unit 40.
  • the mechanical brake 16 may be interlocked with regenerative braking by the traveling motors 14L and 14R, or may generate braking force separately from the regenerative braking by the traveling motors 14L and 14R.
  • the mechanical brake 16 may be operated by a dedicated pedal or the like provided in the cab 5.
  • the mechanical brake output device 17 operates according to the operation of the dedicated pedal.
  • Speed sensors 18L and 18R are attached to the traveling motors 14L and 14R.
  • the speed sensor 18L detects the rotational speed V L of the traveling motor 14L, and outputs a signal corresponding to the rotational speed V L to the traveling device control unit 40.
  • Speed sensor 18R detects the rotational speed V R of the traveling motor 14R, and outputs a signal corresponding to the rotation speed V R to the travel apparatus control unit 40.
  • the rotational speeds V L and V R correspond to the vehicle speed V.
  • the speed sensors 18L and 18R are vehicle speed sensors that acquire the speed (vehicle speed V) of the vehicle (dump truck 1).
  • Current sensors 19L and 19R are attached to the traveling motors 14L and 14R.
  • Current sensor 19L detects a current value I L of the current supplied to the traveling motor 14L.
  • Current sensors 19L outputs a signal corresponding to the current value I L to the travel apparatus control unit 40.
  • Current sensor 19R detects a current value I R of the current supplied to the traveling motor 14R.
  • the current sensor 19R outputs a signal corresponding to the current value I R to the traveling device control unit 40.
  • the power converter 21 controls the power running operation and the regenerative operation of the travel motors 14L and 14R together with the travel device control unit 40 described later.
  • the power converter 21 is housed in a control cabinet 20 that is positioned on the side of the cab 5 and is erected on the deck portion 2 ⁇ / b> A of the vehicle body 2.
  • the power converter 21 includes a converter 22, inverters 24L and 24R, and a chopper 29.
  • the converter 22 is connected to the main generator 12 and constitutes a converter that converts electric power output from the main generator 12. Specifically, converter 22 converts AC power (U-phase, V-phase, and W-phase AC power) output from main generator 12 into DC power (p-phase and n-phase DC power).
  • the converter 22 includes, for example, a rectifier 22A configured using a rectifying element such as a diode or a thyristor, and full-wave rectifying AC power, and a smoothing capacitor 22B connected to a subsequent stage of the rectifier 22A and smoothing the power waveform.
  • Converter 22 is connected to inverters 24L and 24R using a pair of DC buses 23A and 23B.
  • the inverters 24L and 24R control the traveling motors 14L and 14R.
  • the inverters 24L and 24R are configured using a plurality of switching elements (not shown) using, for example, transistors, thyristors, and insulated gate bipolar transistors (IGBT).
  • the inverter 24L is connected to the traveling motor 14L.
  • the inverter 24R is connected to the traveling motor 14R.
  • the inverters 24L and 24R operate based on a control signal from the traveling device control unit 40.
  • the inverters 24L and 24R convert DC power into variable-frequency three-phase AC power and cause the traveling motors 14L and 14R to perform a power running operation. Therefore, the inverters 24L and 24R convert the DC power output from the converter 22 into U-phase, V-phase, and W-phase three-phase AC power by controlling on / off of the switching elements. AC power is supplied to the traveling motors 14L and 14R.
  • the inverters 24L and 24R convert the three-phase AC power into DC power and cause the traveling motors 14L and 14R to regenerate. For this reason, the inverters 24L and 24R convert the electromotive force composed of the three-phase AC power regenerated by the traveling motors 14L and 14R into DC power by controlling on / off of the switching elements, and this DC power is converted to DC power. Output toward the brake resistor 25.
  • the brake resistor 25 consumes the generated electric power as heat when the traveling motors 14L and 14R are regeneratively controlled according to the operation of the retard pedal 7.
  • the brake resistor 25 is connected to the inverters 24L and 24R via the DC buses 23A and 23B.
  • the brake resistor 25 generates heat according to the DC power supplied from the inverters 24L and 24R and consumes the electromotive force regenerated by the traveling motors 14L and 14R.
  • the brake resistor 25 is disposed in a grid box 26 having a rectangular tube shape.
  • the blower 27 is attached to the grid box 26.
  • the blower 27 is configured by an electric motor, and is connected to the sub-generator 13 via a drive circuit 28 including, for example, an inverter.
  • the blower 27 is driven by power supply from the sub-generator 13.
  • the blower 27 is driven in accordance with the heat generation operation of the brake resistor 25, for example, and supplies cooling air toward the brake resistor 25.
  • the blower 27 is a cooling device that cools the brake resistor 25.
  • the cooling device is not limited to the blower 27 that cools the brake resistor 25 with cooling air, but may be a radiator that cools the brake resistor 25 with cooling water, for example.
  • a chopper 29 is provided between the brake resistor 25 and the DC buses 23A and 23B.
  • the chopper 29 is configured by using various switching elements using semiconductor elements, for example.
  • the chopper 29 reduces the DC voltage applied to the DC buses 23A and 23B to a predetermined voltage value or less.
  • the chopper 29 reduces the regenerative power generated by the traveling motors 14L and 14R to a predetermined voltage value or less by controlling on / off of the switching elements, and supplies the regenerative power to the brake resistor 25.
  • an electric current flows into the brake resistor 25, and the brake resistor 25 converts electrical energy into heat energy.
  • the chopper 29 is in a cut-off state and electrically cuts off between the DC buses 23A and 23B and the brake resistor 25.
  • a resistor temperature sensor 30 is attached to the brake resistor 25.
  • the resistor temperature sensor 30 acquires the temperature Tb of the brake resistor 25. That is, the resistor temperature sensor 30 detects the temperature Tb of the brake resistor 25.
  • the resistor temperature sensor 30 outputs a signal corresponding to the temperature Tb to the traveling device control unit 40.
  • the cooling air temperature sensor 31 is attached to the grid box 26.
  • the cooling air temperature sensor 31 is constituted by a temperature sensor provided in a cooling fan of the blower 27, for example.
  • the cooling air temperature sensor 31 detects the temperature Ta of the cooling air taken into the blower 27 from the outside and supplied to the brake resistor 25.
  • the cooling air temperature sensor 31 outputs a signal corresponding to the temperature Ta to the traveling device control unit 40.
  • the temperature Ta of the cooling air is the temperature of the refrigerant of the cooling device.
  • the cooling air temperature sensor 31 is a refrigerant temperature sensor that acquires the temperature of the refrigerant of the cooling device.
  • the refrigerant temperature sensor is not limited to the cooling air temperature sensor, and may be a water temperature sensor that detects the temperature of the cooling water as the refrigerant, for example, when the brake resistor 25 is water-cooled.
  • the dump truck 1 includes a load mass sensor 32 and a road surface gradient sensor 33.
  • the loading mass sensor 32 acquires the loading mass of the vehicle.
  • the load mass sensor 32 detects the mass W of the load loaded on the vessel 3.
  • the load mass sensor 32 is configured by, for example, a displacement sensor attached to the suspension of the front wheels 8L and 8R and the suspension of the rear wheels 9L and 9R.
  • the load mass sensor 32 measures the displacement amount of the suspension stroke, and calculates the mass W of the load loaded on the vessel 3 from the displacement amount.
  • the loaded mass sensor 32 outputs a signal corresponding to the mass W to the traveling device control unit 40.
  • the road surface gradient sensor 33 detects the gradient ⁇ of the road surface on which the dump truck 1 is traveling. Specifically, the road surface gradient sensor 33 acquires the gradient ⁇ of the road surface on which the driving wheels (rear wheels 9L, 9R) of the vehicle come into contact.
  • the road surface gradient sensor 33 is constituted by, for example, an inclination sensor provided in the dump truck 1.
  • the road surface gradient sensor 33 measures the inclination angle of the vehicle and calculates the road surface gradient ⁇ from the inclination angle.
  • the road surface gradient sensor 33 outputs a signal corresponding to the gradient ⁇ to the traveling device control unit 40.
  • the road surface gradient sensor is not limited to the inclination sensor, and may be a displacement sensor that detects a suspension stroke.
  • the road surface gradient sensor can calculate the vehicle inclination angle from the displacement amount of the suspension stroke and acquire the road surface gradient from the inclination angle.
  • the road surface gradient sensor may be configured by a controller in which map data including road surface gradient information is stored, and a position information acquisition system that acquires vehicle position information.
  • the road surface gradient sensor can refer to the gradient information of the road surface at the current location based on the vehicle position information.
  • the traveling device control unit 40 is constituted by, for example, a microcomputer.
  • the traveling device control unit 40 is accommodated in the control cabinet 20 together with the power converter 21.
  • the traveling device control unit 40 is connected to the mechanical brake output device 17 and controls the operation of the mechanical brake 16.
  • the traveling device control unit 40 is connected to the power converter 21 and controls operations of the traveling motors 14L and 14R and the brake resistor 25.
  • the traveling device control unit 40 is connected to the engine control device 11 and controls the operation of the engine 10.
  • the traveling device control unit 40 includes a memory 40A.
  • the memory 40A stores a control processing program for limiting the vehicle speed V shown in FIG.
  • the traveling device control unit 40 executes the control processing program shown in FIG.
  • the traveling device control unit 40 is a controller that controls the speeds of the traveling motors 14L and 14R using the inverters 24L and 24R.
  • the traveling device control unit 40 includes a speed limit calculation device 41 as a maximum speed calculation unit that calculates the maximum speed of the vehicle based on the temperature Tb of the brake resistor 25 acquired by the resistor temperature sensor 30.
  • the traveling device control unit 40 controls the speeds of the traveling motors 14L and 14R so as not to exceed the maximum speed.
  • FIG. 4 shows a detailed block diagram of a portion related to the electric travel drive in the travel device control unit 40.
  • the traveling device control unit 40 includes a speed limit calculation device 41, an accelerator / retard signal calculation device 42 (hereinafter referred to as an A / R signal calculation device 42), a torque command calculation device 43, INV-PWM signal calculation devices 44 and 45, DC A voltage command calculation device 46 (hereinafter referred to as a DC voltage command calculation device 46) and a CHOP-PWM signal calculation device 47 are provided.
  • the speed limit calculation device 41 calculates the forward speed limit value Vflim and the reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30.
  • the speed limit calculation device 41 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
  • the speed limit calculation device 41 decreases the maximum speed of the vehicle (forward speed limit value Vflim, reverse speed limit value Vrlim) as the temperature Tb of the brake resistor 25 increases.
  • the speed limit calculation device 41 decreases the absolute value of the forward speed limit value Vflim and decreases the absolute value of the reverse speed limit value Vrlim as the temperature Tb of the brake resistor 25 increases.
  • the A / R signal calculating device 42 includes an accelerator pedal opening Pa detected by the accelerator pedal opening sensor 6A, a retard pedal opening Pr detected by the retard pedal opening sensor 7A, and a speed limit calculating device 41.
  • the output forward speed limit value Vflim and reverse speed limit value Vrlim are input.
  • the A / R signal calculation device 42 determines the accelerator / retard signal Sar (hereinafter referred to as A / R) based on the accelerator pedal opening degree Pa, the retard pedal opening degree Pr, the forward speed limit value Vflim and the reverse speed limit value Vrlim. Signal Sar).
  • the A / R signal Sar is a signal for accelerating or decelerating the vehicle, for example.
  • the A / R signal Sar takes a positive value.
  • the A / R signal Sar takes a negative value.
  • the A / R signal calculation device 42 outputs the A / R signal Sar to the torque command calculation device 43 and the DC voltage command calculation device 46.
  • the torque command calculation device 43 calculates a torque command Tq for the traveling motors 14L and 14R based on the A / R signal Sar.
  • the torque command Tq is a value corresponding to the torque generated by the traveling motors 14L, 14R.
  • the INV-PWM signal calculating unit 44 calculates a PWM signal to be output to the inverter 24L based on the torque command Tq, the current value I L, and the rotation speed V L.
  • the switching element of the inverter 24L is turned on / off according to the PWM signal output from the INV-PWM signal arithmetic unit 44.
  • the INV-PWM signal calculating unit 45 calculates a PWM signal to be output to the inverter 24R based on the torque command Tq, the current value I R, and the rotation speed V R.
  • the switching element of the inverter 24L is turned on / off according to the PWM signal output from the INV-PWM signal arithmetic unit 45.
  • the DC voltage command calculation device 46 calculates the DC voltage command Vdc based on the A / R signal Sar.
  • the DC voltage command calculation device 46 outputs the DC voltage command Vdc to the CHOP-PWM signal calculation device 47.
  • the DC voltage command Vdc is also used for output voltage control of the traveling motors 14L and 14R. For this reason, the DC voltage output from the converter 22 is controlled so as to have a desired voltage value based on the DC voltage command Vdc.
  • the DC voltage command Vdc output from the DC voltage command calculation device 46 is input to the CHOP-PWM signal calculation device 47.
  • the CHOP-PWM signal calculation device 47 calculates the PWM signal output to the chopper 29 based on the DC voltage command Vdc.
  • the switching element of the chopper 29 is turned on / off according to the PWM signal output from the CHOP-PWM signal arithmetic unit 47.
  • the traveling device control unit 40 controls the traveling motors 14L, 14R powering and regeneration based on the A / R signal Sar to adjust the speed of the vehicle.
  • the electric power generated by the regenerative control of the traveling motors 14L and 14R is mainly consumed as heat by the brake resistor 25.
  • a series of operations for consuming generated power by regenerative control as heat by the brake resistor 25 is an example of a power generation brake.
  • the power generation brake may be executed by an operation of storing generated power in a power storage device (not shown).
  • FIG. 5 shows a detailed block diagram of the A / R signal arithmetic unit 42.
  • a / R signal calculation unit 42 an accelerator pedal opening Pa, retard pedal opening Pr, forward speed limit Vflim, reverse speed limit Vrlim, the rotational speed V L, based on V R, the A / R signal Sar Calculate.
  • the accelerator pedal opening degree Pa is set to a positive value
  • the retard pedal opening degree Pr is set to a negative value.
  • the A / R signal calculation device 42 includes a reference signal calculation unit 51 that calculates a reference signal P0 of the A / R signal Sar, a correction signal calculation unit 52 that calculates an A / R correction signal ⁇ P, an adder 53, 2 limiter 54.
  • the reference signal calculation unit 51 outputs a reference signal P0 based on the accelerator pedal opening degree Pa and the retard pedal opening degree Pr.
  • the reference signal calculation unit 51 includes an inverter 51A that reverses the retard pedal opening Pr to a negative value, and a selection switch 51B.
  • the selection switch 51B receives a signal P1 of the accelerator pedal opening Pa and a signal P2 obtained by inverting the retard pedal opening Pr negatively.
  • the selection switch 51B outputs the signal P2 as the reference signal P0 when the signal P2 is negative, that is, when the retard pedal 7 is depressed.
  • the reference signal P0 has a magnitude of the retard pedal opening Pr and takes a negative value.
  • the selection switch 51B outputs the signal P1 as the reference signal P0 when the signal P2 is other than negative, that is, when the retard pedal 7 is not depressed.
  • the reference signal P0 has a magnitude of the accelerator pedal opening degree Pa and takes a positive value.
  • the correction signal calculation unit 52 outputs an A / R correction signal ⁇ P based on the forward speed limit value Vflim, the reverse speed limit value Vrlim, and the rotational speeds V L and V R.
  • the correction signal calculation unit 52 includes a vehicle speed calculation device 52A, subtractors 52B and 52C, a selection switch 52D, a PI control unit 52E, and a first limiter 52F.
  • the rotational speeds V L and V R are input to the vehicle speed calculation device 52A.
  • the vehicle speed calculation device 52A calculates the vehicle speed V based on the rotation speeds V L and V R. Specifically, for example, the vehicle speed calculation device 52A compares the rotation speed V L with the rotation speed V R and outputs the one having the larger absolute speed value as the vehicle speed V.
  • the vehicle speed calculation device 52A may output the average value of the rotation speed V L and the rotation speed V R as the vehicle speed V.
  • the vehicle speed V takes a positive value when the dump truck 1 is moving forward.
  • the vehicle speed V takes a negative value when the dump truck 1 is moving backward.
  • the subtractor 52B outputs a value obtained by subtracting the vehicle speed V from the forward speed limit value Vflim as a subtraction value ⁇ Vf.
  • the forward speed limit value Vflim is a positive value. Therefore, when the dump truck 1 is moving forward (V> 0) and the forward speed limit value Vflim is larger than the vehicle speed V (Vflim> V), the subtraction value ⁇ Vf becomes a positive value.
  • the subtraction value ⁇ Vf is a negative value. That is, when the vehicle needs to be decelerated, the subtraction value ⁇ Vf becomes a negative value.
  • the subtractor 52C outputs a value obtained by subtracting the reverse speed limit value Vrlim from the vehicle speed V as a subtraction value ⁇ Vr.
  • the reverse speed limit value Vrlim is a negative value. Therefore, when the dump truck 1 is moving backward (V ⁇ 0) and the absolute value of the reverse speed limit value Vrlim is larger than the absolute value of the vehicle speed V (
  • the subtraction value ⁇ Vf and the subtraction value ⁇ Vr are input to the selection switch 52D.
  • the selection switch 52D outputs the subtraction value ⁇ Vr as the speed difference ⁇ V when the vehicle speed V is negative, that is, when the dump truck 1 is moving backward (V ⁇ 0).
  • the selection switch 52D outputs the subtraction value ⁇ Vf as the speed difference ⁇ V when the vehicle speed V is other than negative (V ⁇ 0), that is, when the dump truck 1 is moving forward or stopped.
  • the A / R signal calculation device 42 can limit the vehicle speed V by the forward speed limit value Vflim.
  • the A / R signal calculation device 42 can limit the vehicle speed V by the reverse speed limit value Vrlim.
  • the PI control unit 52E calculates the reference correction signal ⁇ P0 based on the speed difference ⁇ V output from the selection switch 52D. Specifically, the PI control unit 52E calculates the reference correction signal ⁇ P0 by adding the proportional calculation value of the speed difference ⁇ V and the integral calculation value of the speed difference ⁇ V. At this time, the proportional gain and integral gain of the PI control unit 52E are designed so that the control does not diverge, mainly considering the response speed of the motor torque output with respect to the input of the A / R signal Sar and the inertia weight of the vehicle with respect to the torque output, for example.
  • the first limiter 52F has, for example, a map M1 shown in FIG. 6, and limits the reference correction signal ⁇ P0 to a value between 0% and ⁇ 100%. At this time, the upper limit of the limiter is 0%, and the lower limit of the limiter is -100%. For this reason, when the reference correction signal ⁇ P0 is larger than 0% ( ⁇ P0> 0), the first limiter 52F outputs the A / R correction signal ⁇ P that is 0%. When the reference correction signal ⁇ P0 is smaller than ⁇ 100% ( ⁇ P0 ⁇ 100), the first limiter 52F outputs the A / R correction signal ⁇ P which becomes ⁇ 100%. When the reference correction signal ⁇ P0 is a value between 0% and ⁇ 100%, the first limiter 52F outputs the A / R correction signal ⁇ P having the same value as the reference correction signal ⁇ P0.
  • the lower limit of the first limiter 52F may be a value obtained by inverting the positive value of the accelerator pedal opening degree Pa negatively.
  • the lower limit of the A / R correction signal ⁇ P is a value obtained by making the current accelerator pedal opening degree Pa negative. As a result, the final output of the A / R signal Sar can be prevented from becoming a negative value.
  • the adder 53 adds the reference signal P0 and the A / R correction signal ⁇ P, and outputs the added value P3.
  • the second limiter 54 has, for example, a map M2 shown in FIG. 2, and limits the addition value P3 to a value between 100% and ⁇ 100%.
  • the second limiter 54 outputs an A / R signal Sar.
  • the second limiter 54 When the added value P3 is larger than 100% (P3> 100), the second limiter 54 outputs the A / R signal Sar having reached 100%. When the added value P3 is smaller than ⁇ 100% (P3 ⁇ 100), the second limiter 54 outputs the A / R signal Sar which is ⁇ 100%. When the addition value P3 is a value between 100% and -100%, the second limiter 54 outputs the A / R signal Sar having the same value as the addition value P3.
  • the A / R correction signal ⁇ P has a value of 0% or less ( ⁇ P ⁇ 0). For this reason, when the vehicle speed V exceeds the forward speed limit value Vflim, or when the vehicle speed V exceeds the reverse speed limit value Vrlim, the A / R signal calculation device 42 determines from the reference signal P0. A value obtained by subtracting the absolute value of the A / R correction signal ⁇ P is output as the A / R signal Sar. As a result, the A / R signal calculation device 42 can control the vehicle speed V so as not to exceed the forward speed limit value Vflim or the reverse speed limit value Vrlim.
  • FIG. 8 is a block diagram of the speed limit calculation device 41 according to the first embodiment.
  • the speed limit calculation device 41 includes a forward speed limit calculation unit 41A that calculates a forward speed limit value Vflim that is a maximum forward speed, and a reverse speed limit calculation unit 41B that calculates a reverse speed limit value Vrlim that is a maximum reverse speed. doing.
  • the forward speed limit calculation unit 41A decreases the absolute value of the forward speed limit value Vflim as the temperature Tb of the brake resistor 25 increases.
  • the forward speed limit calculation unit 41A includes a forward maximum speed map Mf1.
  • the forward maximum speed map Mf1 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25.
  • the reverse speed limit calculation unit 41B decreases the absolute value of the reverse speed limit value Vrlim as the temperature Tb of the brake resistor 25 increases.
  • the reverse speed limit calculation unit 41B includes a reverse maximum speed map Mr1.
  • the reverse maximum speed map Mr1 calculates a reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25.
  • the forward maximum speed map Mf1 has a characteristic line 41A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim. As indicated by the characteristic line 41A1, the forward speed limit value Vflim is constant at the maximum speed Vfmax when the brake resistor 25 is lower than the lower limit temperature TfL. The forward speed limit value Vflim monotonously decreases from the lower limit temperature TfL to the upper limit temperature Tfh. The forward speed limit value Vflim is constant at the minimum speed Vfmin when it is higher than the upper limit temperature TfH.
  • the maximum speed Vfmax is set based on, for example, the maximum output of the electric motor (travel motors 14L, 14R) or the mechanical allowable input.
  • the minimum speed Vfmin is set to a minimum speed required when the vehicle is moved for evacuation, for example.
  • the minimum speed Vfmin may be set to a maximum speed at which the motor can be driven when the output of the motor is limited based on overheating of the brake resistor 25, for example.
  • the upper limit temperature TfH is a protection temperature at which the brake resistor 25 needs to be protected from heating. For example, when the brake resistor 25 is heated to the upper limit temperature TfH, the vehicle issues a warning or the like.
  • the lower limit temperature TfL is set by the following method.
  • the temperature Tb of the brake resistor 25 exceeds the protection temperature (upper limit temperature TfH). Therefore, the temperature rise rate ⁇ Tb / ⁇ t of the brake resistor 25 is estimated under use conditions such that the protection temperature of the brake resistor 25 is exceeded. Based on this temperature increase rate ⁇ Tb / ⁇ t, the vehicle speed is limited a predetermined time ⁇ ts before the point in time when the protection temperature is exceeded.
  • the predetermined time ⁇ ts is set to a time during which at least the vehicle speed can be sufficiently reduced to a speed at which regenerative braking is unnecessary.
  • the ambient temperature is the maximum use temperature
  • the temperature Tb of the brake resistor 25 is the protection temperature
  • the maximum regenerative torque of the electric motor is continuously applied at the maximum speed Vfmax.
  • the temperature rise rate ⁇ Tb / ⁇ t of the brake resistor 25 is estimated.
  • the temperature increase rate ⁇ Tb / ⁇ t is multiplied by a predetermined time ⁇ ts to obtain a temperature increase ⁇ Tb (Vfmax) after the predetermined time ⁇ ts.
  • the predetermined time ⁇ ts is set to a value of about 30 seconds, for example.
  • the lower limit temperature TfL is obtained by subtracting this temperature increase ⁇ Tb (Vfmax) from the upper limit temperature TfH, which is the protection temperature, based on the following equation (2).
  • the temperature rise speed of the brake resistor 25 at this speed is similarly estimated, and the temperature rise is obtained by multiplying the temperature rise speed by a predetermined time ⁇ ts. By subtracting this temperature rise from the upper limit temperature TfH, the lower limit temperature at which the speed limit is required at the assumed speed is obtained.
  • the maximum forward speed map Mf1 based on this relationship is created.
  • the forward speed limit value Vflim is a speed at which the temperature Tb of the brake resistor 25 becomes an equilibrium state at the protection temperature.
  • a lower speed may be set as the forward speed limit value Vflim in order to bring the vehicle to a low speed state early.
  • the reverse maximum speed map Mr1 shown in FIG. 10 has a characteristic line 41B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim.
  • the reverse maximum speed map Mr1 has a characteristic line 41B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim.
  • the reverse speed limit value Vrlim is constant at the maximum speed Vrmax having the maximum absolute value when the brake resistor 25 is lower than the lower limit temperature TrL.
  • the absolute value of the reverse speed limit value Vrlim monotonously decreases between the lower limit temperature TrL and the upper limit temperature Trh.
  • the reverse speed limit value Vrlim is constant at the minimum speed Vrmin at which the absolute value is minimized.
  • the reverse maximum speed map Mr1 is set in the same way as the maximum forward speed map Mf1.
  • the reverse maximum speed map Mr1 may be a map obtained by inverting the maximum forward speed map Mf1 on the horizontal axis. That is, the characteristic line 41B1 and the characteristic line 41A1 may be axisymmetric with respect to the horizontal axis.
  • the maximum speed Vrmax at the time of reverse travel may be set to a value smaller than the maximum speed Vfmax at the time of forward travel in consideration of a decrease in visibility of the operator during reverse travel.
  • the lower limit temperature TrL during reverse travel may be different from the lower limit temperature TfL during forward travel.
  • the upper limit temperature TrH during reverse travel may be the same value as the upper limit temperature TfH during forward travel, or may be a different value.
  • the forward speed limit calculation unit 41A shown in FIG. 9 continuously decreases the absolute value of the forward speed limit value Vflim as the temperature Tb of the brake resistor 25 increases.
  • the present invention is not limited to this, and the forward speed limit calculating unit 41A may gradually decrease the absolute value of the forward speed limit value Vflim as the temperature Tb of the brake resistor 25 increases.
  • the reverse speed limit calculating unit 41B may gradually decrease the absolute value of the reverse speed limit value Vrlim as the temperature Tb of the brake resistor 25 increases.
  • control processing for limiting the vehicle speed V by the speed limit calculation device 41 and the A / R signal calculation device 42 will be described with reference to FIG.
  • the speed limit calculation device 41 is input with the temperature Tb of the brake resistor 25, and the A / R signal calculation device 42 has the accelerator pedal opening degree Pa.
  • the signal P1 and the signal P2 of the retard pedal opening Pb are input.
  • the A / R signal calculation device 42 obtains the vehicle speed V based on the rotational speeds V L and V R of the traveling motors 14L and 14R.
  • step S1 it is determined whether the vehicle speed V is 0 or more.
  • the vehicle speed V is 0 or more (V ⁇ 0), and the dump truck 1 is moving forward. Therefore, the process proceeds to step S2, and the forward speed limit value Vflim is calculated based on the temperature Tb of the brake resistor 25.
  • the vehicle speed V is subtracted from the forward speed limit value Vflim using the subtractor 52B. Then, using the selection switch 52D, the subtraction value ⁇ Vf output from the subtractor 52B is set to the speed difference ⁇ V.
  • step S1 when it is determined “NO” in step S1, the vehicle speed V is lower than 0 (V ⁇ 0), and the dump truck 1 is moving backward. Therefore, the process proceeds to step S4, and the reverse speed limit value Vrlim is calculated based on the temperature Tb of the brake resistor 25. In the subsequent step S5, the reverse speed limit value Vrlim is subtracted from the vehicle speed V using the subtractor 52C. Then, the subtraction value ⁇ Vr output from the subtractor 52C is set to the speed difference ⁇ V using the selection switch 52D.
  • step S6 an A / R correction signal ⁇ P is calculated based on the speed difference ⁇ V. Specifically, the A / R correction signal ⁇ P is calculated from the speed difference ⁇ V using the PI control unit 52E and the first limiter 52F.
  • step S7 it is determined whether or not the retard pedal 7 is operated. Specifically, it is determined whether or not the signal P2 obtained by reversing the retard pedal opening Pr negatively is a negative value. If “YES” is determined in the step S7, the retard pedal 7 is operated, and the signal P2 becomes a negative value (P2 ⁇ 0). For this reason, the process proceeds to step S8, and the signal P2 is set to the reference signal P0 using the selection switch 51B.
  • step S8 S9 is completed, the process proceeds to step S10.
  • step 10 the adder 53 is used to add the reference signal P 0 and the A / R correction signal ⁇ P.
  • step S11 the A / R signal Sar is calculated from the added value P3 output from the adder 53 using the second limiter 54.
  • the dump truck 1 consumes the generated power, which is the product of the torque and the rotation speeds V L and V R of the motor, as heat by the brake resistor 25. Due to the heat generated by this power generation, the temperature Tb of the brake resistor 25 rises.
  • the forward speed limit value Vflim becomes small according to the maximum forward speed map Mf1 (time point t1).
  • the A / R signal Sar is reduced and the vehicle speed V decreases so as to follow the forward speed limit value Vflim.
  • the decrease in the vehicle speed V means a decrease in the rotation speeds V L and V R of the electric motor. Therefore, the electric power generated by the electric motor is reduced, and the heat generated by the brake resistor 25 is also reduced. As a result, the temperature rise rate of the brake resistor 25 becomes gentle (section from time t1 to time t2).
  • the temperature Tb of the brake resistor 25 exceeds the protection temperature (upper limit temperature TfH) as indicated by a broken line A in FIG.
  • the dump truck 1 reduces the vehicle speed V due to speed limitation. As a result, the heat generated by the brake resistor 25 is reduced, so that the final equilibrium temperature of the brake resistor 25 is suppressed to the protection temperature or lower (section from time t2 to time t3).
  • the downward road gradient becomes small.
  • the negative torque (deceleration torque) output from the electric motor becomes small. Therefore, the generated power is further reduced and the heat generated by the brake resistor 25 is further reduced, so that the temperature Tb of the brake resistor 25 is lowered.
  • the forward speed limit value Vflim returns to the initial speed (maximum speed Vfmax) (time point t5). At this time, the vehicle speed V can be returned to the initial speed in accordance with the operation of the accelerator pedal 6 or the retard pedal 7.
  • heat generation of the brake resistor 25 is determined by the vehicle speed V and the reduced negative torque. At this time, the brake resistor 25 converges to an arbitrary thermal equilibrium temperature.
  • the forward speed limit value Vflim changes according to the temperature Tb of the brake resistor 25.
  • the A / R signal Sar is controlled so that the vehicle speed V becomes smaller than the forward speed limit value Vflim. Therefore, the vehicle speed V is controlled to decrease as the temperature of the brake resistor 25 increases.
  • the thermal equilibrium temperature of the brake resistor 25 is finally kept low. Therefore, if the forward maximum speed map Mf1 and the reverse maximum speed map Mr1 are appropriately set, the vehicle speed V can be controlled so that the thermal equilibrium temperature of the brake resistor 25 does not exceed the protection temperature.
  • the dump truck 1 includes the traveling device control unit 40 (controller) that controls the speeds of the traveling motors 14L and 14R (electric motors).
  • the travel device control unit 40 calculates a maximum vehicle speed (forward speed limit value Vflim and reverse speed limit value Vrlim) based on the temperature Tb of the brake resistor 25 acquired by the resistor temperature sensor 30.
  • 41 maximum speed calculation unit is provided to control the speed of the motor so as not to exceed the maximum speed.
  • the speed limit calculation device 41 calculates the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25. At this time, the speed limit calculation device 41 decreases the absolute value of the forward speed limit value Vflim that becomes the maximum speed as the temperature Tb of the brake resistor 25 increases.
  • the vehicle speed V exceeds the forward speed limit value Vflim
  • the A / R signal Sar decreases, and the dump truck 1 is set so that the vehicle speed V becomes smaller than the forward speed limit value Vflim. Is controlled. Therefore, the vehicle speed V is always limited so as not to exceed the forward speed limit value Vflim that changes according to the temperature Tb of the brake resistor 25.
  • the vehicle speed V can be reduced to the minimum speeds Vfmin and Vfmin only by the power generation brake of the brake resistor 25, and it is not necessary to use the mechanical brake 16 except in an emergency.
  • the use frequency of the mechanical brake 16 can be suppressed, the maintenance cost related to the mechanical brake 16 can be reduced.
  • FIG. 13 to FIG. 15 show a second embodiment of the present invention.
  • the feature of the second embodiment is that the speed limit calculating device calculates the maximum speed of the vehicle based on the temperature of the cooling air acquired by the cooling air temperature sensor in addition to the temperature of the brake resistor. .
  • the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
  • the speed limit calculation device 61 as the maximum speed calculation unit according to the second embodiment includes the cooling air temperature acquired by the cooling air temperature sensor 31 in addition to the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30.
  • the forward speed limit value Vflim and the reverse speed limit value Vrlim are calculated based on the temperature Ta.
  • the temperature Ta of the cooling air is the temperature of the refrigerant of the cooling device (blower 27).
  • the speed limit calculation device 61 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
  • the speed limit calculation device 61 includes a forward speed limit calculation unit 61A that calculates a forward speed limit value Vflim that is a maximum forward speed, and a reverse speed limit calculation unit 61B that calculates a reverse speed limit value Vrlim that is a maximum reverse speed. doing.
  • the forward speed limit calculation unit 61A outputs the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air.
  • the forward speed limit calculation unit 61A includes a forward maximum speed map Mf2.
  • the forward maximum speed map Mf2 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air.
  • the forward maximum speed map Mf2 has a characteristic line 61A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim.
  • the characteristic line 61A1 is substantially the same as the characteristic line 41A1 according to the first embodiment.
  • the characteristic line 61A1 shifts to the lower temperature Tb of the brake resistor 25 according to the temperature Ta of the cooling air.
  • normal temperature for example, 25 ° C.
  • the characteristic line 61A1 shifts to the lower temperature Tb of the brake resistor 25 according to the rise.
  • the lower limit temperature TfL decreases as the temperature Ta of the cooling air becomes higher than the normal temperature.
  • the forward speed limit value Vflim when the temperature Ta of the cooling air is higher than the normal temperature, the forward speed limit value Vflim is lower than the maximum speed Vfmax at a lower lower limit temperature TfL than when the temperature Ta of the cooling air is lower than the normal temperature. Further, when the cooling air temperature Ta is higher than the normal temperature, the forward speed limit value Vflim decreases to the minimum speed Vfmin at a lower upper limit temperature TfH than when the cooling air temperature Ta is lower than the normal temperature.
  • the reverse speed limit calculation unit 61B outputs the reverse speed limit value Vrlim according to the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air.
  • the reverse speed limit calculating unit 61B has a reverse maximum speed map Mr2.
  • the reverse maximum speed map Mr2 calculates a reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air.
  • the reverse maximum speed map Mr2 has a characteristic line 61B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. At this time, the characteristic line 61B1 shifts to the lower temperature Tb of the brake resistor 25 as the temperature Ta of the cooling air increases, like the characteristic line 61A1.
  • the dump truck 1 includes a blower 27 as a cooling device that cools the brake resistor 25, and a cooling air temperature sensor 31 (refrigerant temperature sensor) that acquires a temperature Ta of cooling air that serves as a refrigerant of the cooling device.
  • a cooling air temperature sensor 31 refrigerant temperature sensor
  • the forward speed limit value Vflim and the reverse speed limit value Vrlim are determined in consideration of the temperature Ta of the cooling air in addition to the temperature Tb of the brake resistor 25. For this reason, when the temperature of the surrounding environment is low, the possibility that the vehicle speed V is restricted can be reduced by maintaining the speed limit at a high level.
  • the frequency of use of the mechanical brake 16 can be reduced at a wide range of ambient temperatures, and the maintenance cost related to the mechanical brake 16 can be reduced. Can be reduced.
  • FIG. 16 to FIG. 18 show a third embodiment of the present invention.
  • the speed limit calculation device calculates the maximum speed of the vehicle based on the load mass of the vehicle acquired by the load mass sensor in addition to the temperature of the brake resistor.
  • the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
  • the speed limit calculation device 71 as the maximum speed calculation unit according to the third embodiment includes the vehicle loading acquired by the loading mass sensor 32 in addition to the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30. Based on the mass W, the forward speed limit value Vflim and the reverse speed limit value Vrlim are calculated. The speed limit calculation device 71 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
  • the speed limit calculation device 71 includes a forward speed limit calculation unit 71A that calculates a forward speed limit value Vflim that is the maximum forward speed, and a reverse speed limit calculation unit 71B that calculates a reverse speed limit value Vrlim that is the maximum reverse speed. doing.
  • the forward speed limit calculation unit 71A outputs the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25 and the loaded mass W.
  • the forward speed limit calculation unit 71A includes a forward maximum speed map Mf3.
  • the forward maximum speed map Mf3 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25 and the loaded mass W.
  • the forward maximum speed map Mf3 has a characteristic line 71A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim.
  • the characteristic line 71A1 is substantially the same as the characteristic line 41A1 according to the first embodiment.
  • the characteristic line 71A1 shifts to the lower temperature Tb of the brake resistor 25 according to the loaded mass W. Specifically, when the loading mass W increases from 0, the characteristic line 71A1 shifts to the lower temperature Tb of the brake resistor 25 according to the increase amount. For this reason, the lower limit temperature TfL decreases as the loaded mass W increases from 0 (when empty).
  • the vehicle speed V is limited at a lower lower limit temperature TfL than when the loading mass W is zero. Further, when the load mass W is large, the forward speed limit value Vflim is reduced to the minimum speed Vfmin at a lower upper limit temperature TfH than when the load mass W is zero.
  • the reverse speed limit calculation unit 71B outputs the reverse speed limit value Vrlim according to the temperature Tb and the load mass W of the brake resistor 25.
  • the reverse speed limit calculation unit 71B has a reverse maximum speed map Mr3.
  • the reverse maximum speed map Mr3 calculates a reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 and the loaded mass W.
  • the reverse maximum speed map Mr3 has a characteristic line 71B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. At this time, similarly to the characteristic line 71A1, the characteristic line 71B1 shifts to the lower temperature Tb of the brake resistor 25 as the loaded mass W increases.
  • the dump truck 1 includes a loading mass sensor 32 that acquires the loading mass W of the vehicle.
  • the forward speed limit value Vflim and the reverse speed limit value Vrlim are determined in consideration of the load mass W in addition to the temperature Tb of the brake resistor 25.
  • the vehicle is maintained by maintaining the speed limit high.
  • the possibility that the speed V is limited can be reduced.
  • the limit of the vehicle speed V can be increased by a necessary amount. Therefore, in the third embodiment, compared to the first embodiment, the frequency of use of the mechanical brake 16 can be reduced according to the loading situation of the vehicle, and the maintenance cost related to the mechanical brake 16 is reduced. Can be reduced.
  • FIG. 19 to FIG. 21 show a fourth embodiment of the present invention.
  • the speed limit calculation device calculates the maximum speed of the vehicle based on the road surface gradient acquired by the road surface gradient sensor in addition to the temperature of the brake resistor.
  • the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
  • the speed limit calculating device 81 as the maximum speed calculating unit according to the fourth embodiment adds the road surface gradient acquired by the road surface gradient sensor 33. Based on ⁇ , the forward speed limit value Vflim and the reverse speed limit value Vrlim are calculated. The speed limit calculation device 81 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
  • the speed limit calculation device 81 includes a forward speed limit calculation unit 81A that calculates a forward speed limit value Vflim that is a maximum forward speed, and a reverse speed limit calculation unit 81B that calculates a reverse speed limit value Vrlim that is a maximum reverse speed. doing.
  • the forward speed limit calculation unit 81A outputs the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25 and the road surface gradient ⁇ .
  • the forward speed limit calculation unit 81A includes a forward maximum speed map Mf4.
  • the maximum forward speed map Mf4 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25 and the road surface gradient ⁇ .
  • the forward maximum speed map Mf4 has a characteristic line 81A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim.
  • the characteristic line 81A1 is substantially the same as the characteristic line 41A1 according to the first embodiment.
  • the characteristic line 81A1 shifts to the lower temperature Tb of the brake resistor 25 in accordance with the road surface gradient ⁇ . Specifically, when the road surface gradient ⁇ increases in the downward gradient direction, the characteristic line 81A1 shifts to the lower temperature Tb of the brake resistor 25 according to the increase amount. Therefore, the lower limit temperature TfL decreases as the road surface gradient ⁇ increases in the downward gradient direction than the flat road.
  • the vehicle speed V is limited at a lower lower limit temperature TfL compared to a flat road.
  • the forward speed limit value Vflim decreases to the minimum speed Vfmin at a lower upper limit temperature TfH compared to a flat road.
  • the reverse speed limit calculation unit 81B outputs the reverse speed limit value Vrlim according to the temperature Tb of the brake resistor 25 and the road surface gradient ⁇ .
  • the reverse speed limit calculation unit 81B has a reverse maximum speed map Mr4.
  • the reverse maximum speed map Mr4 calculates the reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 and the road surface gradient ⁇ .
  • the reverse maximum speed map Mr4 has a characteristic line 81B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. At this time, the characteristic line 81B1 shifts to the lower temperature Tb of the brake resistor 25 as the descending slope becomes larger, like the characteristic line 81A1.
  • the dump truck 1 is provided with a road surface gradient sensor 33 that acquires a gradient ⁇ of the road surface on which the rear wheels 9L and 9R (drive wheels) of the vehicle come into contact.
  • the forward speed limit value Vflim and the reverse speed limit value Vrlim are determined in consideration of the road surface gradient ⁇ in addition to the temperature Tb of the brake resistor 25.
  • the possibility that the vehicle speed V is restricted can be reduced by maintaining the speed limit at a high level.
  • the limit of the vehicle speed V can be increased by a necessary amount. Therefore, in the fourth embodiment, it is possible to reduce the frequency of use of the mechanical brake 16 in accordance with a wide range of road surface gradient conditions as compared with the first embodiment, and maintenance related to the mechanical brake 16 is possible. Cost can be reduced.
  • the dump truck 1 has been described as an example of the electrically driven vehicle.
  • the present invention is not limited to this, and any electric drive vehicle that can be driven and driven by an electric motor and capable of regenerative braking may be used.
  • the present invention may be applied to a wheel loader.

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Regulating Braking Force (AREA)

Abstract

A dump truck (1) is provided with: travel motors (14L), (14R); inverters (24L), (24R); rear wheels (9L), (9R); a brake resistor (25); a resistor temperature sensor (30); speed sensors (18L), (18R); and a travel device control unit (40). The travel device control unit (40) is equipped with a speed limit calculation device (41) for calculating a forward speed limit value (Vflim) and a reverse speed limit value (Vrlim) on the basis of the temperature (Tb) of the brake resistor (25) obtained by the resistor temperature sensor (30). The travel device control unit (40) controls the speeds of the travel motors (14L), (14R) so as not to exceed the forward speed limit value (Vflim) and the reverse speed limit value (Vrlim).

Description

電気駆動車両Electric drive vehicle
　本発明は、電動機で走行する電気駆動車両に関する。 The present invention relates to an electrically driven vehicle that is driven by an electric motor.
　電動機で走行する電気駆動車両は、制動時に摩擦抵抗を利用する機械ブレーキと、ブレーキ抵抗器で回生電力を消費する発電ブレーキとを使用することができる。メンテナンスコストを低減するためには、機械ブレーキよりも発電ブレーキを優先して使用することが望まれる。しかしながら、ブレーキ抵抗器の温度上昇により発電ブレーキを使用できない場合がある。この点を考慮して、特許文献１に記載された鉄道車両は、運行ルートの長い下り勾配に入る直前の区間を、発電ブレーキ禁止区間として設定している。これにより、特許文献１に記載された鉄道車両は、長い下り勾配に入るときのブレーキ抵抗器の温度を、予め低くする。この結果、特許文献１に記載された鉄道車両は、長い下り勾配区間で発電ブレーキの連続使用を可能としている。 An electrically driven vehicle that runs on an electric motor can use a mechanical brake that uses frictional resistance during braking and a power generation brake that consumes regenerative power with a brake resistor. In order to reduce the maintenance cost, it is desirable to use the power generation brake in preference to the mechanical brake. However, there are cases where the power generation brake cannot be used due to the temperature rise of the brake resistor. Considering this point, the railway vehicle described in Patent Document 1 sets a section immediately before entering a long downward slope of the operation route as a power generation brake prohibition section. As a result, the railcar described in Patent Document 1 previously reduces the temperature of the brake resistor when entering a long downward slope. As a result, the railway vehicle described in Patent Document 1 enables continuous use of the power generation brake in a long downward slope section.
特開２０１３－１９８２１３号公報JP 2013-198213 A
　電気駆動車両では、発電ブレーキを過度に使用すると、ブレーキ抵抗器の過熱により、発電ブレーキを使用できない状態になる。この状態で制動するためには、機械ブレーキを使用しなければならない。機械ブレーキの使用率が増加すると、メンテナンスの作業頻度が増加し、車両の休止時間の増加を含めて、コスト増加を招いてしまう。 In an electrically driven vehicle, if the power generation brake is used excessively, the power generation brake cannot be used due to overheating of the brake resistor. In order to brake in this state, a mechanical brake must be used. When the usage rate of the mechanical brake increases, the frequency of maintenance work increases, leading to an increase in cost, including an increase in vehicle downtime.
　本発明は、上述した従来技術の問題に鑑みなされたもので、本発明の目的は、ブレーキ抵抗器の温度上昇を抑制し、発電ブレーキの失効を防止することができる電気駆動車両を提供することにある。 The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an electric drive vehicle that can suppress an increase in the temperature of a brake resistor and prevent a power generation brake from being expired. It is in.
　上述した課題を解決するため、本発明は、電動機と、前記電動機を制御するインバータと、前記電動機により駆動される駆動輪と、リタードペダルの操作に応じて前記電動機を回生制御するときに発電された電力を熱として消費するブレーキ抵抗器と、前記ブレーキ抵抗器の温度を取得する抵抗器温度センサと、車両の速度を取得する車両速度センサと、前記インバータを用いて前記電動機の速度を制御するコントローラと、を備えた電気駆動車両において、前記コントローラは、前記抵抗器温度センサによって取得した前記ブレーキ抵抗器の温度に基づいて、前記車両の最大速度を演算する最大速度演算部を備え、前記最大速度を超過しないように前記電動機の速度を制御することを特徴としている。 In order to solve the above-described problems, the present invention generates electric power when regenerative control of the electric motor is performed according to an operation of an electric motor, an inverter that controls the electric motor, a drive wheel that is driven by the electric motor, and a retard pedal. A brake resistor that consumes the electric power as heat; a resistor temperature sensor that acquires the temperature of the brake resistor; a vehicle speed sensor that acquires a vehicle speed; and the inverter that controls the speed of the motor. An electric drive vehicle comprising: a controller; and the controller includes a maximum speed calculation unit that calculates a maximum speed of the vehicle based on a temperature of the brake resistor acquired by the resistor temperature sensor, and the maximum The speed of the electric motor is controlled so as not to exceed the speed.
　本発明によれば、ブレーキ抵抗器の温度に応じて車両の走行速度を制限することができ、機械ブレーキの使用率を低減することができる。 According to the present invention, the traveling speed of the vehicle can be limited according to the temperature of the brake resistor, and the usage rate of the mechanical brake can be reduced.
本発明の第１の実施の形態によるダンプトラックを示す正面図である。1 is a front view showing a dump truck according to a first embodiment of the present invention. ダンプトラックの走行駆動用システムを示す全体構成図である。It is a whole lineblock diagram showing the system for driving of a dump truck. 図２中の電力変換機の構成を示す構成図である。It is a block diagram which shows the structure of the power converter in FIG. 走行装置制御部の構成を示すブロック図である。It is a block diagram which shows the structure of a traveling apparatus control part. アクセル／リタード信号演算装置を示すブロック図である。It is a block diagram which shows an accelerator / retard signal calculating device. 第１リミッタを示す説明図である。It is explanatory drawing which shows a 1st limiter. 第２リミッタを示す説明図である。It is explanatory drawing which shows a 2nd limiter. 第１の実施の形態による速度制限演算装置を示すブロック図である。It is a block diagram which shows the speed limitation calculating device by 1st Embodiment. 図８中の前進速度制限演算部を示す説明図である。It is explanatory drawing which shows the forward speed limitation calculating part in FIG. 図８中の後進速度制限演算部を示す説明図である。It is explanatory drawing which shows the reverse speed restriction | limiting calculating part in FIG. アクセル／リタード信号演算装置および速度制限演算装置による車両速度の制限処理を示す流れ図である。It is a flowchart which shows the limiting process of the vehicle speed by an accelerator / retard signal calculating device and a speed limit calculating device. ブレーキ抵抗器の温度、車両速度、Ａ／Ｒ信号、電動機トルク、回生電力、路面勾配の時間変化の一例を示すタイミングチャートである。It is a timing chart which shows an example of the time change of the temperature of a brake resistor, vehicle speed, an A / R signal, an electric motor torque, regenerative electric power, and a road surface gradient. 第２の実施の形態による速度制限演算装置を示すブロック図である。It is a block diagram which shows the speed limit calculating device by 2nd Embodiment. 図１３中の前進速度制限演算部を示す説明図である。It is explanatory drawing which shows the forward speed restriction | limiting calculating part in FIG. 図１３中の後進速度制限演算部を示す説明図である。It is explanatory drawing which shows the reverse speed limitation calculating part in FIG. 第３の実施の形態による速度制限演算装置を示すブロック図である。It is a block diagram which shows the speed limit calculating device by 3rd Embodiment. 図１６中の前進速度制限演算部を示す説明図である。It is explanatory drawing which shows the forward speed restriction | limiting calculating part in FIG. 図１６中の後進速度制限演算部を示す説明図である。It is explanatory drawing which shows the reverse speed restriction | limiting calculating part in FIG. 第４の実施の形態による速度制限演算装置を示すブロック図である。It is a block diagram which shows the speed limit calculating device by 4th Embodiment. 図１９中の前進速度制限演算部を示す説明図である。It is explanatory drawing which shows the forward speed restriction | limiting calculating part in FIG. 図１９中の後進速度制限演算部を示す説明図である。It is explanatory drawing which shows the reverse speed restriction | limiting calculating part in FIG.
　以下、本発明の実施の形態による電気駆動車両としてダンプトラックを例に挙げて、添付図面を参照しつつ詳細に説明する。 Hereinafter, a dump truck will be described as an example of an electrically driven vehicle according to an embodiment of the present invention and will be described in detail with reference to the accompanying drawings.
　図１ないし図３は、第１の実施の形態によるダンプトラック１を示している。ダンプトラック１は、前輪８Ｌ，８Ｒ、後輪９Ｌ，９Ｒ、走行用モータ１４Ｌ，１４Ｒ、速度センサ１８Ｌ，１８Ｒ、インバータ２４Ｌ，２４Ｒ、ブレーキ抵抗器２５、抵抗器温度センサ３０、走行装置制御部４０を備えている。 1 to 3 show a dump truck 1 according to the first embodiment. The dump truck 1 includes front wheels 8L and 8R, rear wheels 9L and 9R, travel motors 14L and 14R, speed sensors 18L and 18R, inverters 24L and 24R, a brake resistor 25, a resistor temperature sensor 30, and a travel device controller 40. It has.
　図１および図２に示すように、車体２は、フレーム構造体を構成する。車体２の上側には、ホイストシリンダ４によって後部側を支点として傾転（起伏）可能なベッセル３（荷台）が搭載されている。 As shown in FIG. 1 and FIG. 2, the vehicle body 2 constitutes a frame structure. Mounted on the upper side of the vehicle body 2 is a vessel 3 (loading platform) that can be tilted (raised and lowered) with a hoist cylinder 4 as a fulcrum.
　キャブ５は、ベッセル３の前側に位置して車体２の前部上側に設けられている。キャブ５は、例えば車体２の左側に位置して平板状の床板となるデッキ部２Ａ上に配設されている。キャブ５は、ダンプトラック１の運転者（オペレータ）が乗降する運転室を形成している。キャブ５内には、運転席、エンジンスイッチ、シフトレバー、操舵ハンドル（いずれも図示せず）が設けられると共に、アクセルペダル６、リタードペダル７が設けられている。 The cab 5 is provided on the front upper side of the vehicle body 2 and located on the front side of the vessel 3. The cab 5 is disposed on the deck portion 2 </ b> A which is located on the left side of the vehicle body 2 and becomes a flat floor plate, for example. The cab 5 forms a cab where a driver (operator) of the dump truck 1 gets on and off. The cab 5 is provided with a driver's seat, an engine switch, a shift lever, a steering handle (all not shown), and an accelerator pedal 6 and a retard pedal 7.
　アクセルペダル６は、車両を加速させるときに、オペレータによって踏込み操作される。アクセルペダル６には、アクセルペダル開度センサ６Ａが取り付けられている。アクセルペダル開度センサ６Ａは、踏込み量に応じたアクセルペダル６の開度Ｐa［％］を検出する。アクセルペダル開度センサ６Ａは、開度Ｐaに応じた信号を、走行装置制御部４０に出力する。このとき、開度Ｐaは、アクセルペダル６が無操作なときに０％となり、アクセルペダル６が最大操作されたときに１００％となる。 The accelerator pedal 6 is depressed by an operator when accelerating the vehicle. An accelerator pedal opening sensor 6A is attached to the accelerator pedal 6. The accelerator pedal opening sensor 6A detects the opening degree Pa [%] of the accelerator pedal 6 according to the depression amount. The accelerator pedal opening sensor 6A outputs a signal corresponding to the opening Pa to the traveling device control unit 40. At this time, the opening degree Pa is 0% when the accelerator pedal 6 is not operated, and is 100% when the accelerator pedal 6 is fully operated.
　リタードペダル７は、車両を減速させるときに、オペレータによって踏込み操作される。リタードペダル７には、リタードペダル開度センサ７Ａが取り付けられている。リタードペダル開度センサ７Ａは、踏込み量に応じたリタードペダル７の開度Ｐr［％］を検出する。リタードペダル開度センサ７Ａは、開度Ｐrに応じた信号を、走行装置制御部４０に出力する。このとき、開度Ｐrは、リタードペダル７が無操作なときに０％となり、リタードペダル７が最大操作されたときに１００％となる。 The retard pedal 7 is depressed by the operator when decelerating the vehicle. A retard pedal opening sensor 7A is attached to the retard pedal 7. The retard pedal opening sensor 7A detects the opening Pr [%] of the retard pedal 7 according to the depression amount. The retard pedal opening sensor 7A outputs a signal corresponding to the opening Pr to the traveling device control unit 40. At this time, the opening degree Pr becomes 0% when the retard pedal 7 is not operated, and becomes 100% when the retard pedal 7 is fully operated.
　前輪８Ｌ，８Ｒは、車体２の前部下側に回転可能に設けられている。前輪８Ｌ，８Ｒは、従動輪となっている。前輪８Ｌは車体２の左側に配置されている。前輪８Ｒは車体２の右側に配置されている。これら左，右の前輪８Ｌ，８Ｒは、運転者によって操舵（ステアリング操作）される舵取り車輪となっている。これらの前輪８Ｌ，８Ｒは、後輪９Ｌ，９Ｒと同様に、例えば２～４ｍ程度のタイヤ径（外径寸法）をもって形成されている。 The front wheels 8L and 8R are rotatably provided below the front part of the vehicle body 2. The front wheels 8L and 8R are driven wheels. The front wheel 8L is disposed on the left side of the vehicle body 2. The front wheel 8R is disposed on the right side of the vehicle body 2. These left and right front wheels 8L and 8R are steering wheels that are steered (steered) by the driver. These front wheels 8L and 8R are formed with a tire diameter (outer diameter size) of about 2 to 4 m, for example, similarly to the rear wheels 9L and 9R.
　後輪９Ｌ，９Ｒは、走行用モータ１４Ｌ，１４Ｒによって駆動される駆動輪となっている。後輪９Ｌ，９Ｒは、車体２の後部側に回転可能に設けられている。後輪９Ｌは車体２の左側に配置されている。後輪９Ｒは車体２の右側に配置されている。左，右の後輪９Ｌ，９Ｒが回転駆動することにより、ダンプトラック１は走行駆動する。 The rear wheels 9L and 9R are driving wheels driven by the traveling motors 14L and 14R. The rear wheels 9L and 9R are rotatably provided on the rear side of the vehicle body 2. The rear wheel 9L is disposed on the left side of the vehicle body 2. The rear wheel 9 </ b> R is disposed on the right side of the vehicle body 2. When the left and right rear wheels 9L and 9R are rotationally driven, the dump truck 1 is driven to travel.
　エンジン１０は、傾動可能なベッセル３（荷台）の下側に配置されている。具体的には、エンジン１０は、キャブ５の下側に位置して車体２内に設けられている。エンジン１０は、例えば大型のディーゼルエンジンによって構成されている。エンジン１０は、主発電機１２および副発電機１３を駆動する。また、エンジン１０は、油圧ポンプ（図示せず）等を駆動する。エンジン１０には、エンジン回転速度を制御するエンジン制御装置１１が設けられている。 The engine 10 is disposed below the tiltable vessel 3 (loading platform). Specifically, the engine 10 is provided in the vehicle body 2 at the lower side of the cab 5. The engine 10 is constituted by, for example, a large diesel engine. The engine 10 drives the main generator 12 and the sub-generator 13. The engine 10 drives a hydraulic pump (not shown) and the like. The engine 10 is provided with an engine control device 11 that controls the engine rotation speed.
　主発電機１２および副発電機１３は、エンジン１０に機械的に接続されている。主発電機１２は、エンジン１０によって駆動され、３相交流電力を発生させる。副発電機１３も、エンジン１０によって駆動される。このとき、副発電機１３の発電電力は、主発電機１２の発電電力よりも小さい。副発電機１３は、送風機２７等の駆動回路２８に接続され、送風機２７等に駆動電力を供給している。 The main generator 12 and the sub-generator 13 are mechanically connected to the engine 10. Main generator 12 is driven by engine 10 to generate three-phase AC power. The sub-generator 13 is also driven by the engine 10. At this time, the generated power of the sub-generator 13 is smaller than the generated power of the main generator 12. The sub-generator 13 is connected to a drive circuit 28 such as a blower 27 and supplies drive power to the blower 27 and the like.
　走行用モータ１４Ｌ，１４Ｒは、電動機である。走行用モータ１４Ｌ，１４Ｒは、車体２にアクスルハウジング（図示せず）を介して設けられている。走行用モータ１４Ｌは、減速機構１５Ｌを介して左側の後輪９Ｌに機械的に接続され、後輪９Ｌを駆動する。走行用モータ１４Ｒは、減速機構１５Ｒを介して右側の後輪９Ｒに機械的に接続され、後輪９Ｒを駆動する。走行用モータ１４Ｌ，１４Ｒは、主発電機１２から電力変換機２１を介して供給される電力によって回転駆動する。 The traveling motors 14L and 14R are electric motors. The traveling motors 14L and 14R are provided on the vehicle body 2 via an axle housing (not shown). The travel motor 14L is mechanically connected to the left rear wheel 9L via the speed reduction mechanism 15L and drives the rear wheel 9L. The traveling motor 14R is mechanically connected to the right rear wheel 9R via the speed reduction mechanism 15R and drives the rear wheel 9R. The traveling motors 14L and 14R are rotationally driven by electric power supplied from the main generator 12 via the power converter 21.
　各走行用モータ１４Ｌ，１４Ｒは、電力変換機２１によって制御され、それぞれ独立して回転駆動する。電力変換機２１は、走行装置制御部４０からの制御信号に基づいて、車両の直進時に左，右の後輪９Ｌ，９Ｒの回転速度を同じにし、旋回時に旋回方向に応じて左，右の後輪９Ｌ，９Ｒの回転速度を異ならせる等の制御を行う。 The traveling motors 14L and 14R are controlled by the power converter 21 and are driven to rotate independently. Based on the control signal from the traveling device control unit 40, the power converter 21 makes the rotational speeds of the left and right rear wheels 9L, 9R the same when the vehicle goes straight, and changes the left and right according to the turning direction when turning. Control such as changing the rotational speeds of the rear wheels 9L and 9R is performed.
　前輪８Ｌ，８Ｒおよび後輪９Ｌ，９Ｒには、機械ブレーキ１６がそれぞれ取り付けられている。機械ブレーキ１６は、機械的な摩擦力を利用して制動力を発生させる各種のブレーキによって構成されている。機械ブレーキ１６は、機械ブレーキ出力装置１７から供給される圧油に応じて、前輪８Ｌ，８Ｒおよび後輪９Ｌ，９Ｒに制動力を付与する。機械ブレーキ出力装置１７は、走行装置制御部４０からの制御信号に基づいて、機械ブレーキ１６に制動力を発生させる。 A mechanical brake 16 is attached to each of the front wheels 8L and 8R and the rear wheels 9L and 9R. The mechanical brake 16 is composed of various brakes that generate a braking force using a mechanical frictional force. The mechanical brake 16 applies a braking force to the front wheels 8L and 8R and the rear wheels 9L and 9R according to the pressure oil supplied from the mechanical brake output device 17. The mechanical brake output device 17 causes the mechanical brake 16 to generate a braking force based on a control signal from the traveling device control unit 40.
　機械ブレーキ１６は、走行用モータ１４Ｌ，１４Ｒによる回生制動と連動してもよく、走行用モータ１４Ｌ，１４Ｒによる回生制動とは別個に、制動力を発生させてもよい。機械ブレーキ１６を独立して動作させる場合、機械ブレーキ１６は、キャブ５内に設けられた専用ペダル等によって操作されてもよい。この場合、専用ペダルの操作に応じて、機械ブレーキ出力装置１７は動作する。 The mechanical brake 16 may be interlocked with regenerative braking by the traveling motors 14L and 14R, or may generate braking force separately from the regenerative braking by the traveling motors 14L and 14R. When the mechanical brake 16 is operated independently, the mechanical brake 16 may be operated by a dedicated pedal or the like provided in the cab 5. In this case, the mechanical brake output device 17 operates according to the operation of the dedicated pedal.
　走行用モータ１４Ｌ，１４Ｒには、速度センサ１８Ｌ，１８Ｒが取り付けられている。速度センサ１８Ｌは、走行用モータ１４Ｌの回転速度ＶLを検出し、回転速度ＶLに応じた信号を走行装置制御部４０に出力する。速度センサ１８Ｒは、走行用モータ１４Ｒの回転速度ＶRを検出し、回転速度ＶRに応じた信号を走行装置制御部４０に出力する。回転速度ＶL，ＶRは、車両速度Ｖに対応している。このため、速度センサ１８Ｌ，１８Ｒは、車両（ダンプトラック１）の速度（車両速度Ｖ）を取得する車両速度センサとなっている。 Speed sensors 18L and 18R are attached to the traveling motors 14L and 14R. The speed sensor 18L detects the rotational speed V L of the traveling motor 14L, and outputs a signal corresponding to the rotational speed V L to the traveling device control unit 40. Speed sensor 18R detects the rotational speed V R of the traveling motor 14R, and outputs a signal corresponding to the rotation speed V R to the travel apparatus control unit 40. The rotational speeds V L and V R correspond to the vehicle speed V. For this reason, the speed sensors 18L and 18R are vehicle speed sensors that acquire the speed (vehicle speed V) of the vehicle (dump truck 1).
　走行用モータ１４Ｌ，１４Ｒには、電流センサ１９Ｌ，１９Ｒが取り付けられている。電流センサ１９Ｌは、走行用モータ１４Ｌに供給される電流の電流値ＩLを検出する。電流センサ１９Ｌは、電流値ＩLに応じた信号を走行装置制御部４０に出力する。電流センサ１９Ｒは、走行用モータ１４Ｒに供給される電流の電流値ＩRを検出する。電流センサ１９Ｒは、電流値ＩRに応じた信号を走行装置制御部４０に出力する。 Current sensors 19L and 19R are attached to the traveling motors 14L and 14R. Current sensor 19L detects a current value I L of the current supplied to the traveling motor 14L. Current sensors 19L outputs a signal corresponding to the current value I L to the travel apparatus control unit 40. Current sensor 19R detects a current value I R of the current supplied to the traveling motor 14R. The current sensor 19R outputs a signal corresponding to the current value I R to the traveling device control unit 40.
　次に、ダンプトラック１に搭載された走行駆動用システムについて、図３を参照して説明する。 Next, the traveling drive system mounted on the dump truck 1 will be described with reference to FIG.
　電力変換機２１は、後述の走行装置制御部４０と共に走行用モータ１４Ｌ，１４Ｒの力行動作と回生動作とを制御する。電力変換機２１は、キャブ５の側方に位置して車体２のデッキ部２Ａ上に立設されたコントロールキャビネット２０に収容されている。電力変換機２１は、コンバータ２２、インバータ２４Ｌ，２４Ｒおよびチョッパ２９を備えている。 The power converter 21 controls the power running operation and the regenerative operation of the travel motors 14L and 14R together with the travel device control unit 40 described later. The power converter 21 is housed in a control cabinet 20 that is positioned on the side of the cab 5 and is erected on the deck portion 2 </ b> A of the vehicle body 2. The power converter 21 includes a converter 22, inverters 24L and 24R, and a chopper 29.
　コンバータ２２は、主発電機１２に接続され、主発電機１２の出力する電力を変換する変換器を構成している。具体的には、コンバータ２２は、主発電機１２が出力する交流電力（Ｕ相、Ｖ相、Ｗ相の３相交流電力）を直流電力（ｐ相、ｎ相の直流電力）に変換する。コンバータ２２は、例えばダイオード、サイリスタ等の整流素子を用いて構成され交流電力を全波整流する整流器２２Ａと、整流器２２Ａの後段に接続され電力波形を平滑化する平滑コンデンサ２２Ｂとを備えている。コンバータ２２は、一対の直流母線２３Ａ，２３Ｂを用いてインバータ２４Ｌ，２４Ｒに接続されている。 The converter 22 is connected to the main generator 12 and constitutes a converter that converts electric power output from the main generator 12. Specifically, converter 22 converts AC power (U-phase, V-phase, and W-phase AC power) output from main generator 12 into DC power (p-phase and n-phase DC power). The converter 22 includes, for example, a rectifier 22A configured using a rectifying element such as a diode or a thyristor, and full-wave rectifying AC power, and a smoothing capacitor 22B connected to a subsequent stage of the rectifier 22A and smoothing the power waveform. Converter 22 is connected to inverters 24L and 24R using a pair of DC buses 23A and 23B.
　インバータ２４Ｌ，２４Ｒは、走行用モータ１４Ｌ，１４Ｒを制御する。インバータ２４Ｌ，２４Ｒは、例えばトランジスタ、サイリスタ、絶縁ゲートバイポーラトランジスタ（ＩＧＢＴ）を用いた複数のスイッチング素子（図示せず）を用いて構成されている。インバータ２４Ｌは、走行用モータ１４Ｌに接続されている。インバータ２４Ｒは、走行用モータ１４Ｒに接続されている。インバータ２４Ｌ，２４Ｒは、走行装置制御部４０からの制御信号に基づいて動作する。 The inverters 24L and 24R control the traveling motors 14L and 14R. The inverters 24L and 24R are configured using a plurality of switching elements (not shown) using, for example, transistors, thyristors, and insulated gate bipolar transistors (IGBT). The inverter 24L is connected to the traveling motor 14L. The inverter 24R is connected to the traveling motor 14R. The inverters 24L and 24R operate based on a control signal from the traveling device control unit 40.
　ダンプトラック１の走行時には、インバータ２４Ｌ，２４Ｒは、直流電力を可変周波数の３相交流電力に変換し、走行用モータ１４Ｌ，１４Ｒを力行動作させる。このため、インバータ２４Ｌ，２４Ｒは、スイッチング素子のオン／オフを制御することによって、コンバータ２２から出力された直流電力をＵ相、Ｖ相、Ｗ相の３相交流電力に変換し、この３相交流電力を走行用モータ１４Ｌ，１４Ｒに供給する。 When the dump truck 1 is traveling, the inverters 24L and 24R convert DC power into variable-frequency three-phase AC power and cause the traveling motors 14L and 14R to perform a power running operation. Therefore, the inverters 24L and 24R convert the DC power output from the converter 22 into U-phase, V-phase, and W-phase three-phase AC power by controlling on / off of the switching elements. AC power is supplied to the traveling motors 14L and 14R.
　一方、ダンプトラック１の減速時には、インバータ２４Ｌ，２４Ｒは、３相交流電力を直流電力に変換し、走行用モータ１４Ｌ，１４Ｒを回生動作させる。このため、インバータ２４Ｌ，２４Ｒは、スイッチング素子のオン／オフを制御することによって、走行用モータ１４Ｌ，１４Ｒで回生された３相交流電力からなる起電力を直流電力に変換し、この直流電力をブレーキ抵抗器２５に向けて出力する。 On the other hand, when the dump truck 1 is decelerated, the inverters 24L and 24R convert the three-phase AC power into DC power and cause the traveling motors 14L and 14R to regenerate. For this reason, the inverters 24L and 24R convert the electromotive force composed of the three-phase AC power regenerated by the traveling motors 14L and 14R into DC power by controlling on / off of the switching elements, and this DC power is converted to DC power. Output toward the brake resistor 25.
　ブレーキ抵抗器２５は、リタードペダル７の操作に応じて走行用モータ１４Ｌ，１４Ｒを回生制御するときに、発電された電力を熱として消費する。ブレーキ抵抗器２５は、直流母線２３Ａ，２３Ｂを介してインバータ２４Ｌ，２４Ｒに接続されている。ブレーキ抵抗器２５は、インバータ２４Ｌ，２４Ｒから供給される直流電力に応じて発熱し、走行用モータ１４Ｌ，１４Ｒで回生される起電力を消費する。 The brake resistor 25 consumes the generated electric power as heat when the traveling motors 14L and 14R are regeneratively controlled according to the operation of the retard pedal 7. The brake resistor 25 is connected to the inverters 24L and 24R via the DC buses 23A and 23B. The brake resistor 25 generates heat according to the DC power supplied from the inverters 24L and 24R and consumes the electromotive force regenerated by the traveling motors 14L and 14R.
　ブレーキ抵抗器２５は、角筒状をなすグリッドボックス２６内に配設されている。送風機２７は、グリッドボックス２６に取付けられている。送風機２７は、電動モータによって構成され、例えばインバータ等からなる駆動回路２８を介して副発電機１３に接続されている。送風機２７は、副発電機１３からの給電によって駆動する。送風機２７は、例えばブレーキ抵抗器２５の発熱動作に応じて駆動し、ブレーキ抵抗器２５に向けて冷却風を供給する。このため、送風機２７は、ブレーキ抵抗器２５を冷却する冷却装置となっている。なお、冷却装置は、冷却風によってブレーキ抵抗器２５を空冷する送風機２７に限らず、例えば冷却水によってブレーキ抵抗器２５を水冷するラジエータでもよい。 The brake resistor 25 is disposed in a grid box 26 having a rectangular tube shape. The blower 27 is attached to the grid box 26. The blower 27 is configured by an electric motor, and is connected to the sub-generator 13 via a drive circuit 28 including, for example, an inverter. The blower 27 is driven by power supply from the sub-generator 13. The blower 27 is driven in accordance with the heat generation operation of the brake resistor 25, for example, and supplies cooling air toward the brake resistor 25. For this reason, the blower 27 is a cooling device that cools the brake resistor 25. The cooling device is not limited to the blower 27 that cools the brake resistor 25 with cooling air, but may be a radiator that cools the brake resistor 25 with cooling water, for example.
　図３に示すように、ブレーキ抵抗器２５と直流母線２３Ａ，２３Ｂとの間には、チョッパ２９が設けられている。このチョッパ２９は、例えば半導体素子を用いた各種のスイッチング素子を用いて構成されている。ダンプトラック１の減速時には、チョッパ２９は、直流母線２３Ａ，２３Ｂに印加される直流電圧を、所定の電圧値以下まで低下させる。即ち、チョッパ２９は、スイッチング素子のオン／オフを制御することによって、走行用モータ１４Ｌ，１４Ｒによる回生電力を所定の電圧値以下まで低下させて、ブレーキ抵抗器２５に供給する。これにより、ブレーキ抵抗器２５に電流が流れて、ブレーキ抵抗器２５は、電気エネルギを熱エネルギに変換する。一方、ダンプトラック１の走行時には、チョッパ２９は、遮断状態となり、直流母線２３Ａ，２３Ｂとブレーキ抵抗器２５との間を電気的に遮断する。 As shown in FIG. 3, a chopper 29 is provided between the brake resistor 25 and the DC buses 23A and 23B. The chopper 29 is configured by using various switching elements using semiconductor elements, for example. When the dump truck 1 is decelerated, the chopper 29 reduces the DC voltage applied to the DC buses 23A and 23B to a predetermined voltage value or less. In other words, the chopper 29 reduces the regenerative power generated by the traveling motors 14L and 14R to a predetermined voltage value or less by controlling on / off of the switching elements, and supplies the regenerative power to the brake resistor 25. Thereby, an electric current flows into the brake resistor 25, and the brake resistor 25 converts electrical energy into heat energy. On the other hand, when the dump truck 1 is traveling, the chopper 29 is in a cut-off state and electrically cuts off between the DC buses 23A and 23B and the brake resistor 25.
　ブレーキ抵抗器２５には、抵抗器温度センサ３０が取り付けられている。抵抗器温度センサ３０は、ブレーキ抵抗器２５の温度Ｔbを取得する。即ち、抵抗器温度センサ３０は、ブレーキ抵抗器２５の温度Ｔbを検出する。抵抗器温度センサ３０は、温度Ｔbに応じた信号を走行装置制御部４０に出力する。 A resistor temperature sensor 30 is attached to the brake resistor 25. The resistor temperature sensor 30 acquires the temperature Tb of the brake resistor 25. That is, the resistor temperature sensor 30 detects the temperature Tb of the brake resistor 25. The resistor temperature sensor 30 outputs a signal corresponding to the temperature Tb to the traveling device control unit 40.
　グリッドボックス２６には、冷却風温度センサ３１が取り付けられている。冷却風温度センサ３１は、例えば送風機２７の冷却ファンに備えられる温度センサによって構成されている。冷却風温度センサ３１は、外部から送風機２７に取り入れられ、ブレーキ抵抗器２５に供給される冷却風の温度Ｔaを検出する。冷却風温度センサ３１は、温度Ｔaに応じた信号を走行装置制御部４０に出力する。このとき、冷却風の温度Ｔaは、冷却装置の冷媒の温度となっている。このため、冷却風温度センサ３１は、冷却装置の冷媒の温度を取得する冷媒温度センサとなっている。なお、冷媒温度センサは、冷却風温度センサに限らず、例えばブレーキ抵抗器２５を水冷する場合には、冷媒としての冷却水の温度を検出する水温センサでもよい。 The cooling air temperature sensor 31 is attached to the grid box 26. The cooling air temperature sensor 31 is constituted by a temperature sensor provided in a cooling fan of the blower 27, for example. The cooling air temperature sensor 31 detects the temperature Ta of the cooling air taken into the blower 27 from the outside and supplied to the brake resistor 25. The cooling air temperature sensor 31 outputs a signal corresponding to the temperature Ta to the traveling device control unit 40. At this time, the temperature Ta of the cooling air is the temperature of the refrigerant of the cooling device. For this reason, the cooling air temperature sensor 31 is a refrigerant temperature sensor that acquires the temperature of the refrigerant of the cooling device. The refrigerant temperature sensor is not limited to the cooling air temperature sensor, and may be a water temperature sensor that detects the temperature of the cooling water as the refrigerant, for example, when the brake resistor 25 is water-cooled.
　ダンプトラック１は、積載質量センサ３２および路面勾配センサ３３を備えている。積載質量センサ３２は、車両の積載質量を取得する。このとき、積載質量センサ３２は、ベッセル３に積載された積載物の質量Ｗを検出する。具体的には、積載質量センサ３２は、例えば、前輪８Ｌ，８Ｒのサスペンションと、後輪９Ｌ，９Ｒのサスペンションとに取り付けられている変位センサによって構成されている。積載質量センサ３２は、サスペンションストロークの変位量を測定し、その変位量からベッセル３に積載された積載物の質量Ｗを演算する。積載質量センサ３２は、質量Ｗに応じた信号を走行装置制御部４０に出力する。 The dump truck 1 includes a load mass sensor 32 and a road surface gradient sensor 33. The loading mass sensor 32 acquires the loading mass of the vehicle. At this time, the load mass sensor 32 detects the mass W of the load loaded on the vessel 3. Specifically, the load mass sensor 32 is configured by, for example, a displacement sensor attached to the suspension of the front wheels 8L and 8R and the suspension of the rear wheels 9L and 9R. The load mass sensor 32 measures the displacement amount of the suspension stroke, and calculates the mass W of the load loaded on the vessel 3 from the displacement amount. The loaded mass sensor 32 outputs a signal corresponding to the mass W to the traveling device control unit 40.
　路面勾配センサ３３は、ダンプトラック１が走行している路面の勾配θを検出する。具体的には、路面勾配センサ３３は、車両の駆動輪（後輪９Ｌ，９Ｒ）が接地する路面の勾配θを取得する。路面勾配センサ３３は、例えばダンプトラック１に備えられている傾斜センサによって構成されている。路面勾配センサ３３は、車両の傾斜角度を測定し、その傾斜角度から路面の勾配θを演算する。路面勾配センサ３３は、勾配θに応じた信号を走行装置制御部４０に出力する。 The road surface gradient sensor 33 detects the gradient θ of the road surface on which the dump truck 1 is traveling. Specifically, the road surface gradient sensor 33 acquires the gradient θ of the road surface on which the driving wheels ( rear wheels 9L, 9R) of the vehicle come into contact. The road surface gradient sensor 33 is constituted by, for example, an inclination sensor provided in the dump truck 1. The road surface gradient sensor 33 measures the inclination angle of the vehicle and calculates the road surface gradient θ from the inclination angle. The road surface gradient sensor 33 outputs a signal corresponding to the gradient θ to the traveling device control unit 40.
　なお、路面勾配センサは、傾斜センサに限らず、サスペンションストロークを検出する変位センサによって構成してもよい。この場合、路面勾配センサは、サスペンションストロークの変位量から車両の傾斜角度を演算して、傾斜角度から路面勾配を取得することができる。路面勾配センサは、路面の勾配情報を含む地図データが格納されたコントローラと、車両の位置情報を取得する位置情報取得システムとによって構成してもよい。この場合、路面勾配センサは、車両の位置情報に基づいて、現在地の路面の勾配情報を参照することができる。 The road surface gradient sensor is not limited to the inclination sensor, and may be a displacement sensor that detects a suspension stroke. In this case, the road surface gradient sensor can calculate the vehicle inclination angle from the displacement amount of the suspension stroke and acquire the road surface gradient from the inclination angle. The road surface gradient sensor may be configured by a controller in which map data including road surface gradient information is stored, and a position information acquisition system that acquires vehicle position information. In this case, the road surface gradient sensor can refer to the gradient information of the road surface at the current location based on the vehicle position information.
　走行装置制御部４０は、例えばマイクロコンピュータによって構成されている。走行装置制御部４０は、電力変換機２１と一緒にコントロールキャビネット２０に収容されている。走行装置制御部４０は、機械ブレーキ出力装置１７に接続され、機械ブレーキ１６の動作を制御する。走行装置制御部４０は、電力変換機２１に接続され、走行用モータ１４Ｌ，１４Ｒおよびブレーキ抵抗器２５の動作を制御する。これに加えて、走行装置制御部４０は、エンジン制御装置１１に接続され、エンジン１０の動作を制御する。 The traveling device control unit 40 is constituted by, for example, a microcomputer. The traveling device control unit 40 is accommodated in the control cabinet 20 together with the power converter 21. The traveling device control unit 40 is connected to the mechanical brake output device 17 and controls the operation of the mechanical brake 16. The traveling device control unit 40 is connected to the power converter 21 and controls operations of the traveling motors 14L and 14R and the brake resistor 25. In addition, the traveling device control unit 40 is connected to the engine control device 11 and controls the operation of the engine 10.
　走行装置制御部４０は、メモリ４０Ａを備えている。メモリ４０Ａには、図１１に示す車両速度Ｖを制限する制御処理プログラムが格納されている。走行装置制御部４０は、図１１に示す制御処理プログラムを実行する。走行装置制御部４０は、インバータ２４Ｌ，２４Ｒを用いて走行用モータ１４Ｌ，１４Ｒの速度を制御するコントローラとなっている。走行装置制御部４０は、抵抗器温度センサ３０によって取得したブレーキ抵抗器２５の温度Ｔbに基づいて、車両の最大速度を演算する最大速度演算部としての速度制限演算装置４１を備えている。走行装置制御部４０は、最大速度を超過しないように走行用モータ１４Ｌ，１４Ｒの速度を制御する。 The traveling device control unit 40 includes a memory 40A. The memory 40A stores a control processing program for limiting the vehicle speed V shown in FIG. The traveling device control unit 40 executes the control processing program shown in FIG. The traveling device control unit 40 is a controller that controls the speeds of the traveling motors 14L and 14R using the inverters 24L and 24R. The traveling device control unit 40 includes a speed limit calculation device 41 as a maximum speed calculation unit that calculates the maximum speed of the vehicle based on the temperature Tb of the brake resistor 25 acquired by the resistor temperature sensor 30. The traveling device control unit 40 controls the speeds of the traveling motors 14L and 14R so as not to exceed the maximum speed.
　次に、電気的な走行駆動に係る走行装置制御部４０の具体的な構成について、図４を参照して説明する。 Next, a specific configuration of the travel device control unit 40 related to electrical travel drive will be described with reference to FIG.
　図４は、走行装置制御部４０のうち電気的な走行駆動に関する部分の詳細なブロック図を示している。走行装置制御部４０は、速度制限演算装置４１、アクセル／リタード信号演算装置４２（以下、Ａ／Ｒ信号演算装置４２という）、トルク指令演算装置４３、ＩＮＶ－ＰＷＭ信号演算装置４４，４５、直流電圧指令演算装置４６（以下、ＤＣ電圧指令演算装置４６という）、ＣＨＯＰ－ＰＷＭ信号演算装置４７を備えている。 FIG. 4 shows a detailed block diagram of a portion related to the electric travel drive in the travel device control unit 40. The traveling device control unit 40 includes a speed limit calculation device 41, an accelerator / retard signal calculation device 42 (hereinafter referred to as an A / R signal calculation device 42), a torque command calculation device 43, INV-PWM signal calculation devices 44 and 45, DC A voltage command calculation device 46 (hereinafter referred to as a DC voltage command calculation device 46) and a CHOP-PWM signal calculation device 47 are provided.
　速度制限演算装置４１は、抵抗器温度センサ３０によって検出されたブレーキ抵抗器２５の温度Ｔbに基づいて、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを演算する。速度制限演算装置４１は、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを、Ａ／Ｒ信号演算装置４２に出力する。速度制限演算装置４１は、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、車両の最大速度（前進速度制限値Ｖflim、後進速度制限値Ｖrlim）を低下させる。具体的には、速度制限演算装置４１は、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、前進速度制限値Ｖflimの絶対値を低下させ、後進速度制限値Ｖrlimの絶対値を低下させる。 The speed limit calculation device 41 calculates the forward speed limit value Vflim and the reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30. The speed limit calculation device 41 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42. The speed limit calculation device 41 decreases the maximum speed of the vehicle (forward speed limit value Vflim, reverse speed limit value Vrlim) as the temperature Tb of the brake resistor 25 increases. Specifically, the speed limit calculation device 41 decreases the absolute value of the forward speed limit value Vflim and decreases the absolute value of the reverse speed limit value Vrlim as the temperature Tb of the brake resistor 25 increases.
　Ａ／Ｒ信号演算装置４２には、アクセルペダル開度センサ６Ａによって検出されたアクセルペダル開度Ｐaと、リタードペダル開度センサ７Ａによって検出されたリタードペダル開度Ｐrと、速度制限演算装置４１から出力された前進速度制限値Ｖflimおよび後進速度制限値Ｖrlimとが入力される。Ａ／Ｒ信号演算装置４２は、アクセルペダル開度Ｐaと、リタードペダル開度Ｐrと、前進速度制限値Ｖflimおよび後進速度制限値Ｖrlimとに基づいて、アクセル／リタード信号Ｓar（以下、Ａ／Ｒ信号Ｓarという）を演算する。このとき、Ａ／Ｒ信号Ｓarは、例えば車両を加速または減速させる信号である。車両を加速させるときには、Ａ／Ｒ信号Ｓarは、正の値となる。車両を減速させるときには、Ａ／Ｒ信号Ｓarは、負の値となる。Ａ／Ｒ信号演算装置４２は、Ａ／Ｒ信号Ｓarを、トルク指令演算装置４３と、ＤＣ電圧指令演算装置４６とに出力する。 The A / R signal calculating device 42 includes an accelerator pedal opening Pa detected by the accelerator pedal opening sensor 6A, a retard pedal opening Pr detected by the retard pedal opening sensor 7A, and a speed limit calculating device 41. The output forward speed limit value Vflim and reverse speed limit value Vrlim are input. The A / R signal calculation device 42 determines the accelerator / retard signal Sar (hereinafter referred to as A / R) based on the accelerator pedal opening degree Pa, the retard pedal opening degree Pr, the forward speed limit value Vflim and the reverse speed limit value Vrlim. Signal Sar). At this time, the A / R signal Sar is a signal for accelerating or decelerating the vehicle, for example. When accelerating the vehicle, the A / R signal Sar takes a positive value. When the vehicle is decelerated, the A / R signal Sar takes a negative value. The A / R signal calculation device 42 outputs the A / R signal Sar to the torque command calculation device 43 and the DC voltage command calculation device 46.
　トルク指令演算装置４３は、Ａ／Ｒ信号Ｓarに基づいて走行用モータ１４Ｌ，１４Ｒに対するトルク指令Ｔqを演算する。トルク指令Ｔqは、走行用モータ１４Ｌ，１４Ｒに発生させるトルクに応じた値になっている。 The torque command calculation device 43 calculates a torque command Tq for the traveling motors 14L and 14R based on the A / R signal Sar. The torque command Tq is a value corresponding to the torque generated by the traveling motors 14L, 14R.
　ＩＮＶ－ＰＷＭ信号演算装置４４には、トルク指令演算装置４３から出力されたトルク指令Ｔqと、電流センサ１９Ｌによって検出された電流値ＩLと、速度センサ１８Ｌによって検出された走行用モータ１４Ｌの回転速度ＶLとが入力される。ＩＮＶ－ＰＷＭ信号演算装置４４は、トルク指令Ｔqと、電流値ＩLと、回転速度ＶLとに基づいて、インバータ２４Ｌに出力するＰＷＭ信号を演算する。インバータ２４Ｌのスイッチング素子は、ＩＮＶ－ＰＷＭ信号演算装置４４から出力されるＰＷＭ信号に応じてオン／オフする。 The INV-PWM signal calculating unit 44, the torque command Tq output from the torque command computing unit 43, the rotation of the traveling motor 14L, which is detected and the current value I L that is detected by the current sensor 19L, the speed sensor 18L The speed V L is input. The INV-PWM signal calculation device 44 calculates a PWM signal to be output to the inverter 24L based on the torque command Tq, the current value I L, and the rotation speed V L. The switching element of the inverter 24L is turned on / off according to the PWM signal output from the INV-PWM signal arithmetic unit 44.
　ＩＮＶ－ＰＷＭ信号演算装置４５には、トルク指令演算装置４３から出力されたトルク指令Ｔqと、電流センサ１９Ｒによって検出された電流値ＩRと、速度センサ１８Ｒによって検出された走行用モータ１４Ｒの回転速度ＶRとが入力される。ＩＮＶ－ＰＷＭ信号演算装置４５は、トルク指令Ｔqと、電流値ＩRと、回転速度ＶRとに基づいて、インバータ２４Ｒに出力するＰＷＭ信号を演算する。インバータ２４Ｌのスイッチング素子は、ＩＮＶ－ＰＷＭ信号演算装置４５から出力されるＰＷＭ信号に応じてオン／オフする。 The INV-PWM signal calculating unit 45, the torque command Tq output from the torque command computing unit 43, the rotation of the traveling motor 14R detected and the current value I R detected by the current sensor 19R, the speed sensor 18R The speed V R is input. The INV-PWM signal calculation device 45 calculates a PWM signal to be output to the inverter 24R based on the torque command Tq, the current value I R, and the rotation speed V R. The switching element of the inverter 24L is turned on / off according to the PWM signal output from the INV-PWM signal arithmetic unit 45.
　ＤＣ電圧指令演算装置４６は、Ａ／Ｒ信号Ｓarに基づいて、ＤＣ電圧指令Ｖdcを演算する。ＤＣ電圧指令演算装置４６は、ＤＣ電圧指令ＶdcをＣＨＯＰ－ＰＷＭ信号演算装置４７に出力する。 The DC voltage command calculation device 46 calculates the DC voltage command Vdc based on the A / R signal Sar. The DC voltage command calculation device 46 outputs the DC voltage command Vdc to the CHOP-PWM signal calculation device 47.
　なお、ＤＣ電圧指令Ｖdcは、走行用モータ１４Ｌ，１４Ｒの出力電圧制御にも利用されている。このため、コンバータ２２から出力される直流電圧は、ＤＣ電圧指令Ｖdcに基づいて、所望の電圧値となるように制御される。 The DC voltage command Vdc is also used for output voltage control of the traveling motors 14L and 14R. For this reason, the DC voltage output from the converter 22 is controlled so as to have a desired voltage value based on the DC voltage command Vdc.
　ＣＨＯＰ－ＰＷＭ信号演算装置４７には、ＤＣ電圧指令演算装置４６から出力されたＤＣ電圧指令Ｖdcが入力される。ＣＨＯＰ－ＰＷＭ信号演算装置４７は、ＤＣ電圧指令Ｖdcに基づいてチョッパ２９に出力するＰＷＭ信号を演算する。チョッパ２９のスイッチング素子は、ＣＨＯＰ－ＰＷＭ信号演算装置４７から出力されるＰＷＭ信号に応じてオン／オフする。 The DC voltage command Vdc output from the DC voltage command calculation device 46 is input to the CHOP-PWM signal calculation device 47. The CHOP-PWM signal calculation device 47 calculates the PWM signal output to the chopper 29 based on the DC voltage command Vdc. The switching element of the chopper 29 is turned on / off according to the PWM signal output from the CHOP-PWM signal arithmetic unit 47.
　走行装置制御部４０は、Ａ／Ｒ信号Ｓarに基づいて、走行用モータ１４Ｌ，１４Ｒ力行と回生を制御し、車両の速度を調整する。また、走行用モータ１４Ｌ，１４Ｒの回生制御により発電された電力は、ブレーキ抵抗器２５で主に熱として消費される。このように回生制御による発電電力をブレーキ抵抗器２５で熱として消費する一連の動作は、発電ブレーキの一例として挙げられる。なお、発電ブレーキは、発電電力を蓄電装置（図示せず）に蓄える動作によって実行してもよい。 The traveling device control unit 40 controls the traveling motors 14L, 14R powering and regeneration based on the A / R signal Sar to adjust the speed of the vehicle. The electric power generated by the regenerative control of the traveling motors 14L and 14R is mainly consumed as heat by the brake resistor 25. A series of operations for consuming generated power by regenerative control as heat by the brake resistor 25 is an example of a power generation brake. The power generation brake may be executed by an operation of storing generated power in a power storage device (not shown).
　次に、Ａ／Ｒ信号演算装置４２の具体的な構成について、図５ないし図７を参照して説明する。 Next, a specific configuration of the A / R signal arithmetic unit 42 will be described with reference to FIGS.
　図５は、Ａ／Ｒ信号演算装置４２の詳細なブロック図を示している。Ａ／Ｒ信号演算装置４２は、アクセルペダル開度Ｐa、リタードペダル開度Ｐr、前進速度制限値Ｖflim、後進速度制限値Ｖrlim、回転速度ＶL，ＶRに基づいて、Ａ／Ｒ信号Ｓarを演算する。Ａ／Ｒ信号Ｓarを演算するときには、アクセルペダル開度Ｐaを正の値とし、リタードペダル開度Ｐrを負の値とする。 FIG. 5 shows a detailed block diagram of the A / R signal arithmetic unit 42. A / R signal calculation unit 42, an accelerator pedal opening Pa, retard pedal opening Pr, forward speed limit Vflim, reverse speed limit Vrlim, the rotational speed V L, based on V R, the A / R signal Sar Calculate. When calculating the A / R signal Sar, the accelerator pedal opening degree Pa is set to a positive value, and the retard pedal opening degree Pr is set to a negative value.
　Ａ／Ｒ信号演算装置４２は、Ａ／Ｒ信号Ｓarの基準信号Ｐ0を算出する基準信号算出部５１と、Ａ／Ｒ補正信号ΔＰを算出する補正信号算出部５２と、加算器５３と、第２リミッタ５４とを備えている。 The A / R signal calculation device 42 includes a reference signal calculation unit 51 that calculates a reference signal P0 of the A / R signal Sar, a correction signal calculation unit 52 that calculates an A / R correction signal ΔP, an adder 53, 2 limiter 54.
　基準信号算出部５１は、アクセルペダル開度Ｐaとリタードペダル開度Ｐrとに基づいて、基準信号Ｐ0を出力する。基準信号算出部５１は、リタードペダル開度Ｐrを負の値に反転させる反転器５１Ａと、選択スイッチ５１Ｂとを備えている。 The reference signal calculation unit 51 outputs a reference signal P0 based on the accelerator pedal opening degree Pa and the retard pedal opening degree Pr. The reference signal calculation unit 51 includes an inverter 51A that reverses the retard pedal opening Pr to a negative value, and a selection switch 51B.
　選択スイッチ５１Ｂには、アクセルペダル開度Ｐaの信号Ｐ1とリタードペダル開度Ｐrを負に反転させた信号Ｐ2とが入力される。選択スイッチ５１Ｂは、信号Ｐ2が負のとき、即ちリタードペダル７を踏み込んでいるときには、信号Ｐ2を基準信号Ｐ0として出力する。このとき、基準信号Ｐ0は、リタードペダル開度Ｐrの大きさを有し、負の値となる。選択スイッチ５１Ｂは、信号Ｐ2が負以外のとき、即ちリタードペダル７を踏み込んでいないときには、信号Ｐ1を基準信号Ｐ0として出力する。このとき、基準信号Ｐ0は、アクセルペダル開度Ｐaの大きさを有し、正の値となる。 The selection switch 51B receives a signal P1 of the accelerator pedal opening Pa and a signal P2 obtained by inverting the retard pedal opening Pr negatively. The selection switch 51B outputs the signal P2 as the reference signal P0 when the signal P2 is negative, that is, when the retard pedal 7 is depressed. At this time, the reference signal P0 has a magnitude of the retard pedal opening Pr and takes a negative value. The selection switch 51B outputs the signal P1 as the reference signal P0 when the signal P2 is other than negative, that is, when the retard pedal 7 is not depressed. At this time, the reference signal P0 has a magnitude of the accelerator pedal opening degree Pa and takes a positive value.
　補正信号算出部５２は、前進速度制限値Ｖflim、後進速度制限値Ｖrlim、回転速度ＶL，ＶRに基づいて、Ａ／Ｒ補正信号ΔＰを出力する。補正信号算出部５２は、車両速度演算装置５２Ａ、減算器５２Ｂ，５２Ｃ、選択スイッチ５２Ｄ、ＰＩ制御部５２Ｅ、第１リミッタ５２Ｆを備えている。 The correction signal calculation unit 52 outputs an A / R correction signal ΔP based on the forward speed limit value Vflim, the reverse speed limit value Vrlim, and the rotational speeds V L and V R. The correction signal calculation unit 52 includes a vehicle speed calculation device 52A, subtractors 52B and 52C, a selection switch 52D, a PI control unit 52E, and a first limiter 52F.
　車両速度演算装置５２Ａには、回転速度ＶL，ＶRが入力される。車両速度演算装置５２Ａは、回転速度ＶL，ＶRに基づいて、車両速度Ｖを演算する。具体的には、車両速度演算装置５２Ａは、例えば、回転速度ＶLと回転速度ＶRを比較し、速度絶対値が大きい方を、車両速度Ｖとして出力する。なお、車両速度演算装置５２Ａは、回転速度ＶLと回転速度ＶRの平均値を、車両速度Ｖとして出力してもよい。車両速度Ｖは、ダンプトラック１が前進しているときに正の値となる。車両速度Ｖは、ダンプトラック１が後進しているときに負の値となる。 The rotational speeds V L and V R are input to the vehicle speed calculation device 52A. The vehicle speed calculation device 52A calculates the vehicle speed V based on the rotation speeds V L and V R. Specifically, for example, the vehicle speed calculation device 52A compares the rotation speed V L with the rotation speed V R and outputs the one having the larger absolute speed value as the vehicle speed V. The vehicle speed calculation device 52A may output the average value of the rotation speed V L and the rotation speed V R as the vehicle speed V. The vehicle speed V takes a positive value when the dump truck 1 is moving forward. The vehicle speed V takes a negative value when the dump truck 1 is moving backward.
　減算器５２Ｂは、前進速度制限値Ｖflimから車両速度Ｖを引いた値を、減算値ΔＶfとして出力する。このとき、前進速度制限値Ｖflimは、正の値である。このため、ダンプトラック１が前進（Ｖ＞０）している場合であって、前進速度制限値Ｖflimが車両速度Ｖよりも大きい（Ｖflim＞Ｖ）ときには、減算値ΔＶfは正の値となる。ダンプトラック１が前進（Ｖ＞０）している場合であって、前進速度制限値Ｖflimが車両速度Ｖよりも小さい（Ｖflim＜Ｖ）ときには、減算値ΔＶfは負の値となる。即ち、車両の減速が必要なときには、減算値ΔＶfは負の値になる。 The subtractor 52B outputs a value obtained by subtracting the vehicle speed V from the forward speed limit value Vflim as a subtraction value ΔVf. At this time, the forward speed limit value Vflim is a positive value. Therefore, when the dump truck 1 is moving forward (V> 0) and the forward speed limit value Vflim is larger than the vehicle speed V (Vflim> V), the subtraction value ΔVf becomes a positive value. When the dump truck 1 is moving forward (V> 0) and the forward speed limit value Vflim is smaller than the vehicle speed V (Vflim <V), the subtraction value ΔVf is a negative value. That is, when the vehicle needs to be decelerated, the subtraction value ΔVf becomes a negative value.
　減算器５２Ｃは、車両速度Ｖから後進速度制限値Ｖrlimを引いた値を、減算値ΔＶrとして出力する。このとき、後進速度制限値Ｖrlimは、負の値である。このため、ダンプトラック１が後進（Ｖ＜０）している場合であって、後進速度制限値Ｖrlimの絶対値が車両速度Ｖの絶対値よりも大きい（｜Ｖrlim｜＞｜Ｖ｜）ときには、減算値ΔＶrは正の値となる。ダンプトラック１が後進（Ｖ＜０）している場合であって、後進速度制限値Ｖrlimの絶対値が車両速度Ｖの絶対値よりも小さい（｜Ｖflim｜＜｜Ｖ｜）ときには、減算値ΔＶrは負の値となる。即ち、車両の減速が必要なときには、減算値ΔＶrは負の値になる。 The subtractor 52C outputs a value obtained by subtracting the reverse speed limit value Vrlim from the vehicle speed V as a subtraction value ΔVr. At this time, the reverse speed limit value Vrlim is a negative value. Therefore, when the dump truck 1 is moving backward (V <0) and the absolute value of the reverse speed limit value Vrlim is larger than the absolute value of the vehicle speed V (| Vrlim |> | V |), The subtraction value ΔVr is a positive value. When the dump truck 1 is moving backward (V <0) and the absolute value of the reverse speed limit value Vrlim is smaller than the absolute value of the vehicle speed V (| Vflim | <| V |), the subtraction value ΔVr Is negative. That is, when the vehicle needs to be decelerated, the subtraction value ΔVr becomes a negative value.
　選択スイッチ５２Ｄには、減算値ΔＶfと減算値ΔＶrとが入力される。選択スイッチ５２Ｄは、車両速度Ｖが負のとき、即ちダンプトラック１が後進しているとき（Ｖ＜０）には、減算値ΔＶrを速度差ΔＶとして出力する。選択スイッチ５２Ｄは、車両速度Ｖが負以外のとき（Ｖ≧０）、即ちダンプトラック１が前進または停止しているときには、減算値ΔＶfを速度差ΔＶとして出力する。これにより、車両前進時には、Ａ／Ｒ信号演算装置４２は、前進速度制限値Ｖflimによって車両速度Ｖを制限することができる。また、車両後進時には、Ａ／Ｒ信号演算装置４２は、後進速度制限値Ｖrlimによって車両速度Ｖを制限することができる。 The subtraction value ΔVf and the subtraction value ΔVr are input to the selection switch 52D. The selection switch 52D outputs the subtraction value ΔVr as the speed difference ΔV when the vehicle speed V is negative, that is, when the dump truck 1 is moving backward (V <0). The selection switch 52D outputs the subtraction value ΔVf as the speed difference ΔV when the vehicle speed V is other than negative (V ≧ 0), that is, when the dump truck 1 is moving forward or stopped. Thereby, when the vehicle moves forward, the A / R signal calculation device 42 can limit the vehicle speed V by the forward speed limit value Vflim. Further, when the vehicle is moving backward, the A / R signal calculation device 42 can limit the vehicle speed V by the reverse speed limit value Vrlim.
　ＰＩ制御部５２Ｅは、選択スイッチ５２Ｄから出力される速度差ΔＶに基づいて、基準補正信号ΔＰ0を演算する。具体的には、ＰＩ制御部５２Ｅは、速度差ΔＶの比例演算値と、速度差ΔＶの積分演算値とを加算して、基準補正信号ΔＰ0を算出する。このとき、ＰＩ制御部５２Ｅの比例ゲインと積分ゲインは、例えばＡ／Ｒ信号Ｓarの入力に対する電動機トルク出力の応答速度とトルク出力に対する車両の慣性重量を主に考慮して、制御が発散しないように設定される。 The PI control unit 52E calculates the reference correction signal ΔP0 based on the speed difference ΔV output from the selection switch 52D. Specifically, the PI control unit 52E calculates the reference correction signal ΔP0 by adding the proportional calculation value of the speed difference ΔV and the integral calculation value of the speed difference ΔV. At this time, the proportional gain and integral gain of the PI control unit 52E are designed so that the control does not diverge, mainly considering the response speed of the motor torque output with respect to the input of the A / R signal Sar and the inertia weight of the vehicle with respect to the torque output, for example. Set to
　第１リミッタ５２Ｆは、例えば図６に示すマップＭ1を有し、基準補正信号ΔＰ0を、０％から－１００％までの間の値に制限する。このとき、リミッタの上限は０％、リミッタの下限は－１００％としている。このため、基準補正信号ΔＰ0が０％よりも大きい（ΔＰ0＞０）ときには、第１リミッタ５２Ｆは、０％となったＡ／Ｒ補正信号ΔＰを出力する。基準補正信号ΔＰ0が－１００％よりも小さい（ΔＰ0＜－１００）ときには、第１リミッタ５２Ｆは、－１００％となったＡ／Ｒ補正信号ΔＰを出力する。基準補正信号ΔＰ0が０％から－１００％までの間の値のときには、第１リミッタ５２Ｆは、基準補正信号ΔＰ0と同じ値となったＡ／Ｒ補正信号ΔＰを出力する。 The first limiter 52F has, for example, a map M1 shown in FIG. 6, and limits the reference correction signal ΔP0 to a value between 0% and −100%. At this time, the upper limit of the limiter is 0%, and the lower limit of the limiter is -100%. For this reason, when the reference correction signal ΔP0 is larger than 0% (ΔP0> 0), the first limiter 52F outputs the A / R correction signal ΔP that is 0%. When the reference correction signal ΔP0 is smaller than −100% (ΔP0 <−100), the first limiter 52F outputs the A / R correction signal ΔP which becomes −100%. When the reference correction signal ΔP0 is a value between 0% and −100%, the first limiter 52F outputs the A / R correction signal ΔP having the same value as the reference correction signal ΔP0.
　なお、第１リミッタ５２Ｆの下限は、アクセルペダル開度Ｐaの正の値を負に反転させた値としてもよい。この場合、Ａ／Ｒ補正信号ΔＰの下限が、現在のアクセルペダル開度Ｐaを負にした値となる。これにより、Ａ／Ｒ信号Ｓarの最終出力が負の値となるのを避けることができる。 Note that the lower limit of the first limiter 52F may be a value obtained by inverting the positive value of the accelerator pedal opening degree Pa negatively. In this case, the lower limit of the A / R correction signal ΔP is a value obtained by making the current accelerator pedal opening degree Pa negative. As a result, the final output of the A / R signal Sar can be prevented from becoming a negative value.
　加算器５３は、基準信号Ｐ0とＡ／Ｒ補正信号ΔＰとを加算し、これらの加算値Ｐ3を出力する。第２リミッタ５４は、例えば図２に示すマップＭ2を有し、加算値Ｐ3を、１００％から－１００％までの間の値に制限する。第２リミッタ５４は、Ａ／Ｒ信号Ｓarを出力する。 The adder 53 adds the reference signal P0 and the A / R correction signal ΔP, and outputs the added value P3. The second limiter 54 has, for example, a map M2 shown in FIG. 2, and limits the addition value P3 to a value between 100% and −100%. The second limiter 54 outputs an A / R signal Sar.
　加算値Ｐ3が１００％よりも大きい（Ｐ3＞１００）ときには、第２リミッタ５４は、１００％となったＡ／Ｒ信号Ｓarを出力する。加算値Ｐ3が－１００％よりも小さい（Ｐ3＜－１００）ときには、第２リミッタ５４は、－１００％となったＡ／Ｒ信号Ｓarを出力する。加算値Ｐ3が１００％から－１００％までの間の値のときには、第２リミッタ５４は、加算値Ｐ3と同じ値となったＡ／Ｒ信号Ｓarを出力する。 When the added value P3 is larger than 100% (P3> 100), the second limiter 54 outputs the A / R signal Sar having reached 100%. When the added value P3 is smaller than −100% (P3 <−100), the second limiter 54 outputs the A / R signal Sar which is −100%. When the addition value P3 is a value between 100% and -100%, the second limiter 54 outputs the A / R signal Sar having the same value as the addition value P3.
　このとき、Ａ／Ｒ補正信号ΔＰは、０％以下の値となっている（ΔＰ≦０）。このため、車両速度Ｖが前進速度制限値Ｖflimを超過している場合、または車両速度Ｖが後進速度制限値Ｖrlimを超過している場合に、Ａ／Ｒ信号演算装置４２は、基準信号Ｐ0からＡ／Ｒ補正信号ΔＰの絶対値を減じた値を、Ａ／Ｒ信号Ｓarとして出力する。これにより、Ａ／Ｒ信号演算装置４２は、前進速度制限値Ｖflimまたは後進速度制限値Ｖrlimを超過しないように、車両速度Ｖを制御することができる。 At this time, the A / R correction signal ΔP has a value of 0% or less (ΔP ≦ 0). For this reason, when the vehicle speed V exceeds the forward speed limit value Vflim, or when the vehicle speed V exceeds the reverse speed limit value Vrlim, the A / R signal calculation device 42 determines from the reference signal P0. A value obtained by subtracting the absolute value of the A / R correction signal ΔP is output as the A / R signal Sar. As a result, the A / R signal calculation device 42 can control the vehicle speed V so as not to exceed the forward speed limit value Vflim or the reverse speed limit value Vrlim.
　次に、速度制限演算装置４１について、図８ないし図１０を参照して説明する。図８は、第１の実施の形態による速度制限演算装置４１のブロック図に示している。 Next, the speed limit calculation device 41 will be described with reference to FIGS. FIG. 8 is a block diagram of the speed limit calculation device 41 according to the first embodiment.
　速度制限演算装置４１は、前進最大速度となる前進速度制限値Ｖflimを演算する前進速度制限演算部４１Ａと、後進最大速度となる後進速度制限値Ｖrlimを演算する後進速度制限演算部４１Ｂとを有している。前進速度制限演算部４１Ａは、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、前進速度制限値Ｖflimの絶対値を低下させる。前進速度制限演算部４１Ａは、前進最大速度マップＭf1を備えている。前進最大速度マップＭf1は、ブレーキ抵抗器２５の温度Ｔbに基づいて、前進速度制限値Ｖflimを演算する。 The speed limit calculation device 41 includes a forward speed limit calculation unit 41A that calculates a forward speed limit value Vflim that is a maximum forward speed, and a reverse speed limit calculation unit 41B that calculates a reverse speed limit value Vrlim that is a maximum reverse speed. doing. The forward speed limit calculation unit 41A decreases the absolute value of the forward speed limit value Vflim as the temperature Tb of the brake resistor 25 increases. The forward speed limit calculation unit 41A includes a forward maximum speed map Mf1. The forward maximum speed map Mf1 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25.
　また、後進速度制限演算部４１Ｂは、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、後進速度制限値Ｖrlimの絶対値を低下させる。後進速度制限演算部４１Ｂは、後進最大速度マップＭr1を備えている。後進最大速度マップＭr1は、ブレーキ抵抗器２５の温度Ｔbに基づいて、後進速度制限値Ｖrlimを演算する。 Further, the reverse speed limit calculation unit 41B decreases the absolute value of the reverse speed limit value Vrlim as the temperature Tb of the brake resistor 25 increases. The reverse speed limit calculation unit 41B includes a reverse maximum speed map Mr1. The reverse maximum speed map Mr1 calculates a reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25.
　ここで、前進最大速度マップＭf1について、図９を用いて説明する。 Here, the forward maximum speed map Mf1 will be described with reference to FIG.
　前進最大速度マップＭf1は、ブレーキ抵抗器２５の温度Ｔbと前進速度制限値Ｖflimとの関係を示す特性線４１Ａ1を有している。特性線４１Ａ1に示すように、前進速度制限値Ｖflimは、ブレーキ抵抗器２５が下限温度ＴfLよりも低いときには、最大速度Ｖfmaxで一定となる。前進速度制限値Ｖflimは、下限温度ＴfLから上限温度Ｔfhまでの間は単調減少する。前進速度制限値Ｖflimは、上限温度ＴfHよりも高いときには、最小速度Ｖfminで一定となる。 The forward maximum speed map Mf1 has a characteristic line 41A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim. As indicated by the characteristic line 41A1, the forward speed limit value Vflim is constant at the maximum speed Vfmax when the brake resistor 25 is lower than the lower limit temperature TfL. The forward speed limit value Vflim monotonously decreases from the lower limit temperature TfL to the upper limit temperature Tfh. The forward speed limit value Vflim is constant at the minimum speed Vfmin when it is higher than the upper limit temperature TfH.
　最大速度Ｖfmaxは、例えば電動機（走行用モータ１４Ｌ，１４Ｒ）の最大出力や機械的な許容入力に基づいて設定される。最小速度Ｖfminは、例えば車両が退避のために移動させるときに最低限必要な速度に設定される。これに限らず、最小速度Ｖfminは、例えばブレーキ抵抗器２５の過熱に基づいて電動機の出力制限を行ったときに、電動機が駆動できる最大速度に設定してもよい。また、最小速度Ｖfminは、停止速度（Ｖfmin＝０）に設定してもよい。 The maximum speed Vfmax is set based on, for example, the maximum output of the electric motor ( travel motors 14L, 14R) or the mechanical allowable input. The minimum speed Vfmin is set to a minimum speed required when the vehicle is moved for evacuation, for example. For example, the minimum speed Vfmin may be set to a maximum speed at which the motor can be driven when the output of the motor is limited based on overheating of the brake resistor 25, for example. Further, the minimum speed Vfmin may be set to a stop speed (Vfmin = 0).
　上限温度ＴfHは、ブレーキ抵抗器２５を加熱から保護する必要が生じる保護温度である。例えば、この上限温度ＴfHまでブレーキ抵抗器２５が加熱されると、車両はワーニング等を発する。一方、下限温度ＴfLは、以下に示す方法で設定されている。 The upper limit temperature TfH is a protection temperature at which the brake resistor 25 needs to be protected from heating. For example, when the brake resistor 25 is heated to the upper limit temperature TfH, the vehicle issues a warning or the like. On the other hand, the lower limit temperature TfL is set by the following method.
　例えば、最大速度Ｖfmaxでモータの最大回生トルクをかけ続けたときには、ブレーキ抵抗器２５の温度Ｔbは、保護温度（上限温度ＴfH）を超過する。そこで、ブレーキ抵抗器２５の保護温度が超過するような使用条件で、ブレーキ抵抗器２５の温度上昇速度ΔＴb／Δｔを見積る。この温度上昇速度ΔＴb／Δｔに基づいて、保護温度を超過する時点よりも所定時間Δｔs前に車速を制限するようにする。所定時間Δｔsは、少なくとも車速を回生制動が不要となる速度まで十分に低下させることが可能な時間を設定する。 For example, when the maximum regenerative torque of the motor is continuously applied at the maximum speed Vfmax, the temperature Tb of the brake resistor 25 exceeds the protection temperature (upper limit temperature TfH). Therefore, the temperature rise rate ΔTb / Δt of the brake resistor 25 is estimated under use conditions such that the protection temperature of the brake resistor 25 is exceeded. Based on this temperature increase rate ΔTb / Δt, the vehicle speed is limited a predetermined time Δts before the point in time when the protection temperature is exceeded. The predetermined time Δts is set to a time during which at least the vehicle speed can be sufficiently reduced to a speed at which regenerative braking is unnecessary.
　例えば、周囲温度を最大使用温度とし、ブレーキ抵抗器２５の温度Ｔbを保護温度とし、最大速度Ｖfmaxで電動機（走行用モータ１４Ｌ，１４Ｒ）の最大回生トルクをかけ続けた条件を考える。この条件下で、ブレーキ抵抗器２５の温度上昇速度ΔＴb／Δｔを見積る。以下の数１の式に基づいて、この温度上昇速度ΔＴb／Δｔに所定時間Δｔsを乗算して、所定時間Δｔs後の温度上昇分ΔＴb（Ｖfmax）を求める。所定時間Δｔsは、例えば３０秒程度の値に設定される。 For example, a condition is considered in which the ambient temperature is the maximum use temperature, the temperature Tb of the brake resistor 25 is the protection temperature, and the maximum regenerative torque of the electric motor ( travel motors 14L, 14R) is continuously applied at the maximum speed Vfmax. Under this condition, the temperature rise rate ΔTb / Δt of the brake resistor 25 is estimated. Based on the following equation (1), the temperature increase rate ΔTb / Δt is multiplied by a predetermined time Δts to obtain a temperature increase ΔTb (Vfmax) after the predetermined time Δts. The predetermined time Δts is set to a value of about 30 seconds, for example.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　以下の数２の式に基づいて、この温度上昇分ΔＴb（Ｖfmax）を保護温度である上限温度ＴfHから減算することによって、下限温度ＴfLを求める。 The lower limit temperature TfL is obtained by subtracting this temperature increase ΔTb (Vfmax) from the upper limit temperature TfH, which is the protection temperature, based on the following equation (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　車両速度Ｖが最大速度Ｖfmaxよりも小さい速度についても、同様にこの速度におけるブレーキ抵抗器２５の温度上昇速度を見積り、この温度上昇速度に所定時間Δｔsを乗算して、温度上昇分を求める。この温度上昇分を上限温度ＴfHから減算することによって、想定した速度で速度制限が必要となる下限の温度を求める。これにより、前進速度制限値Ｖflimとブレーキ抵抗器２５の温度Ｔbとの関係が求められるから、この関係に基づく前進最大速度マップＭf1が作成される。この前進最大速度マップＭf1を用いて車両の前進速度を制限した場合には、前進速度制限値Ｖflimは、ブレーキ抵抗器２５の温度Ｔbが保護温度で平衡状態になる速度となる。しかしながら、車両を早期に低速状態にするためには、より小さい速度を、前進速度制限値Ｖflimとして設定してもよい。 For the speed at which the vehicle speed V is lower than the maximum speed Vfmax, the temperature rise speed of the brake resistor 25 at this speed is similarly estimated, and the temperature rise is obtained by multiplying the temperature rise speed by a predetermined time Δts. By subtracting this temperature rise from the upper limit temperature TfH, the lower limit temperature at which the speed limit is required at the assumed speed is obtained. Thus, since the relationship between the forward speed limit value Vflim and the temperature Tb of the brake resistor 25 is obtained, the maximum forward speed map Mf1 based on this relationship is created. When the forward speed of the vehicle is limited using the maximum forward speed map Mf1, the forward speed limit value Vflim is a speed at which the temperature Tb of the brake resistor 25 becomes an equilibrium state at the protection temperature. However, a lower speed may be set as the forward speed limit value Vflim in order to bring the vehicle to a low speed state early.
　図１０に示す後進最大速度マップＭr1は、ブレーキ抵抗器２５の温度Ｔbと後進速度制限値Ｖrlimとの関係を示す特性線４１Ｂ1を有している。後進最大速度マップＭr1は、ブレーキ抵抗器２５の温度Ｔbと後進速度制限値Ｖrlimとの関係を示す特性線４１Ｂ1を有している。特性線４１Ｂ1に示すように、後進速度制限値Ｖrlimは、ブレーキ抵抗器２５が下限温度ＴrLよりも低いときには、絶対値が最大となった最大速度Ｖrmaxで一定となる。後進速度制限値Ｖrlimは、下限温度ＴrLから上限温度Ｔrhまでの間は、絶対値が単調減少する。後進速度制限値Ｖrlimは、上限温度ＴrHよりも高いときには、絶対値が最小となった最小速度Ｖrminで一定となる。 The reverse maximum speed map Mr1 shown in FIG. 10 has a characteristic line 41B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. The reverse maximum speed map Mr1 has a characteristic line 41B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. As shown by the characteristic line 41B1, the reverse speed limit value Vrlim is constant at the maximum speed Vrmax having the maximum absolute value when the brake resistor 25 is lower than the lower limit temperature TrL. The absolute value of the reverse speed limit value Vrlim monotonously decreases between the lower limit temperature TrL and the upper limit temperature Trh. When the reverse speed limit value Vrlim is higher than the upper limit temperature TrH, the reverse speed limit value Vrlim is constant at the minimum speed Vrmin at which the absolute value is minimized.
　後進最大速度マップＭr1は、前進最大速度マップＭf1と同じ考え方で設定されている。例えば、後進最大速度マップＭr1は、前進最大速度マップＭf1を横軸で反転させたマップとしてもよい。即ち、特性線４１Ｂ1と特性線４１Ａ1とは、横軸に関して線対称としてもよい。なお、後進時の最大速度Ｖrmaxは、後進時におけるオペレータの視認性の低下を考慮して、前進時の最大速度Ｖfmaxよりも小さい値に設定してもよい。これに伴って、後進時の下限温度ＴrLは、前進時の下限温度ＴfLと異なる値でもよい。また、後進時の上限温度ＴrHは、前進時の上限温度ＴfHと同じ値でもよく、異なる値でもよい。 The reverse maximum speed map Mr1 is set in the same way as the maximum forward speed map Mf1. For example, the reverse maximum speed map Mr1 may be a map obtained by inverting the maximum forward speed map Mf1 on the horizontal axis. That is, the characteristic line 41B1 and the characteristic line 41A1 may be axisymmetric with respect to the horizontal axis. Note that the maximum speed Vrmax at the time of reverse travel may be set to a value smaller than the maximum speed Vfmax at the time of forward travel in consideration of a decrease in visibility of the operator during reverse travel. Accordingly, the lower limit temperature TrL during reverse travel may be different from the lower limit temperature TfL during forward travel. Further, the upper limit temperature TrH during reverse travel may be the same value as the upper limit temperature TfH during forward travel, or may be a different value.
　図９に示す前進速度制限演算部４１Ａは、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、前進速度制限値Ｖflimの絶対値を連続的に低下させるものとした。本発明はこれに限らず、前進速度制限演算部４１Ａは、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、前進速度制限値Ｖflimの絶対値を段階的に低下させてもよい。同様に、後進速度制限演算部４１Ｂは、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、後進速度制限値Ｖrlimの絶対値を段階的に低下させてもよい。 The forward speed limit calculation unit 41A shown in FIG. 9 continuously decreases the absolute value of the forward speed limit value Vflim as the temperature Tb of the brake resistor 25 increases. The present invention is not limited to this, and the forward speed limit calculating unit 41A may gradually decrease the absolute value of the forward speed limit value Vflim as the temperature Tb of the brake resistor 25 increases. Similarly, the reverse speed limit calculating unit 41B may gradually decrease the absolute value of the reverse speed limit value Vrlim as the temperature Tb of the brake resistor 25 increases.
　次に、速度制限演算装置４１およびＡ／Ｒ信号演算装置４２による車両速度Ｖを制限する制御処理について、図１１を参照して説明する。なお、図１１に示す制御処理を実行する時点で、速度制限演算装置４１には、ブレーキ抵抗器２５の温度Ｔbが入力されており、Ａ／Ｒ信号演算装置４２には、アクセルペダル開度Ｐaの信号Ｐ1と、リタードペダル開度Ｐbの信号Ｐ2とが入力されている。また、Ａ／Ｒ信号演算装置４２は、走行用モータ１４Ｌ，１４Ｒの回転速度ＶL，ＶRに基づいて、車両速度Ｖを取得している。 Next, control processing for limiting the vehicle speed V by the speed limit calculation device 41 and the A / R signal calculation device 42 will be described with reference to FIG. When the control process shown in FIG. 11 is executed, the speed limit calculation device 41 is input with the temperature Tb of the brake resistor 25, and the A / R signal calculation device 42 has the accelerator pedal opening degree Pa. The signal P1 and the signal P2 of the retard pedal opening Pb are input. Further, the A / R signal calculation device 42 obtains the vehicle speed V based on the rotational speeds V L and V R of the traveling motors 14L and 14R.
　まず、ステップＳ１では、車両速度Ｖが０以上か否かを判定する。ステップＳ１で「ＹＥＳ」と判定したときには、車両速度Ｖが０以上であり（Ｖ≧０）、ダンプトラック１は前進している。このため、ステップＳ２に移行して、ブレーキ抵抗器２５の温度Ｔbに基づいて、前進速度制限値Ｖflimを演算する。続くステップＳ３では、減算器５２Ｂを用いて前進速度制限値Ｖflimから車両速度Ｖを減算する。そして、選択スイッチ５２Ｄを用いて、減算器５２Ｂから出力された減算値ΔＶfを、速度差ΔＶに設定する。 First, in step S1, it is determined whether the vehicle speed V is 0 or more. When it is determined “YES” in step S1, the vehicle speed V is 0 or more (V ≧ 0), and the dump truck 1 is moving forward. Therefore, the process proceeds to step S2, and the forward speed limit value Vflim is calculated based on the temperature Tb of the brake resistor 25. In the subsequent step S3, the vehicle speed V is subtracted from the forward speed limit value Vflim using the subtractor 52B. Then, using the selection switch 52D, the subtraction value ΔVf output from the subtractor 52B is set to the speed difference ΔV.
　一方、ステップＳ１で「ＮＯ」と判定したときには、車両速度Ｖが０よりも低下しており（Ｖ＜０）、ダンプトラック１は後進している。このため、ステップＳ４に移行して、ブレーキ抵抗器２５の温度Ｔbに基づいて、後進速度制限値Ｖrlimを演算する。続くステップＳ５では、減算器５２Ｃを用いて車両速度Ｖから後進速度制限値Ｖrlimを減算する。そして、選択スイッチ５２Ｄを用いて、減算器５２Ｃから出力される減算値ΔＶrを、速度差ΔＶに設定する。 On the other hand, when it is determined “NO” in step S1, the vehicle speed V is lower than 0 (V <0), and the dump truck 1 is moving backward. Therefore, the process proceeds to step S4, and the reverse speed limit value Vrlim is calculated based on the temperature Tb of the brake resistor 25. In the subsequent step S5, the reverse speed limit value Vrlim is subtracted from the vehicle speed V using the subtractor 52C. Then, the subtraction value ΔVr output from the subtractor 52C is set to the speed difference ΔV using the selection switch 52D.
　ステップＳ３，Ｓ５が終了すると、ステップＳ６に移行する。ステップＳ６では、速度差ΔＶに基づいて、Ａ／Ｒ補正信号ΔＰを演算する。具体的には、ＰＩ制御部５２Ｅおよび第１リミッタ５２Ｆを用いて、速度差ΔＶからＡ／Ｒ補正信号ΔＰを算出する。 When steps S3 and S5 are completed, the process proceeds to step S6. In step S6, an A / R correction signal ΔP is calculated based on the speed difference ΔV. Specifically, the A / R correction signal ΔP is calculated from the speed difference ΔV using the PI control unit 52E and the first limiter 52F.
　続くステップＳ７では、リタードペダル７が操作されているか否かを判定する。具体的には、リタードペダル開度Ｐrを負に反転させた信号Ｐ2が負の値か否かを判定する。ステップＳ７で「ＹＥＳ」と判定したときには、リタードペダル７が操作されて、信号Ｐ2が負の値となっている（Ｐ2＜０）。このため、ステップＳ８に移行して、選択スイッチ５１Ｂを用いて、信号Ｐ2を基準信号Ｐ0に設定する。 In subsequent step S7, it is determined whether or not the retard pedal 7 is operated. Specifically, it is determined whether or not the signal P2 obtained by reversing the retard pedal opening Pr negatively is a negative value. If “YES” is determined in the step S7, the retard pedal 7 is operated, and the signal P2 becomes a negative value (P2 <0). For this reason, the process proceeds to step S8, and the signal P2 is set to the reference signal P0 using the selection switch 51B.
　一方、ステップＳ７で「ＮＯ」と判定したときには、リタードペダル７が操作されておらず、信号Ｐ2は０となっている（Ｐ2＝０）。このため、ステップＳ９に移行して、選択スイッチ５１Ｂを用いて、アクセルペダル開度Ｐaとなった信号Ｐ1を、基準信号Ｐ0に設定する。 On the other hand, when it is determined “NO” in step S7, the retard pedal 7 is not operated, and the signal P2 is 0 (P2 = 0). For this reason, the process proceeds to step S9, and the signal P1 having the accelerator pedal opening degree Pa is set to the reference signal P0 by using the selection switch 51B.
　ステップＳ８，Ｓ９が終了すると、ステップＳ１０に移行する。ステップ１０では、加算器５３を用いて、基準信号Ｐ0とＡ／Ｒ補正信号ΔＰとを加算する。続く、ステップＳ１１では、第２リミッタ５４を用いて、加算器５３から出力される加算値Ｐ3からＡ／Ｒ信号Ｓarを演算する。 When step S8, S9 is completed, the process proceeds to step S10. In step 10, the adder 53 is used to add the reference signal P 0 and the A / R correction signal ΔP. In step S11, the A / R signal Sar is calculated from the added value P3 output from the adder 53 using the second limiter 54.
　次に、ブレーキ抵抗器２５の温度Ｔbに基づいて車両速度Ｖを制限した場合の一例について、図１２を参照して説明する。 Next, an example when the vehicle speed V is limited based on the temperature Tb of the brake resistor 25 will be described with reference to FIG.
　まず、車両（ダンプトラック１）が下り勾配の路面をある一定速度で前進したときを考える。このとき、一定速度は、前進最大速度マップＭf1のブレーキ抵抗器２５の温度Ｔ１以下での前進速度制限値Ｖf1よりも小さいと仮定する。また、説明を簡略化するために、速度変化のための一時的なトルク変化（増加または減少）によるブレーキ抵抗器２５の温度変化は、トルク変化している時間が十分短いと考えて、無視する。 First, let's consider the case where the vehicle (dump truck 1) moves forward at a certain speed on a downhill road surface. At this time, it is assumed that the constant speed is smaller than the forward speed limit value Vf1 at the temperature T1 or less of the brake resistor 25 in the maximum forward speed map Mf1. In order to simplify the explanation, the temperature change of the brake resistor 25 due to a temporary torque change (increase or decrease) due to the speed change is ignored because it is considered that the time during which the torque is changed is sufficiently short. .
　路面の下り勾配が大きいので、車両速度Ｖを一定に保つため電動機（走行用モータ１４Ｌ，１４Ｒ）には負のトルクが定常的に発生する。このとき、ダンプトラック１は、トルクと電動機の回転速度ＶL，ＶRとの積となる発電電力をブレーキ抵抗器２５で熱として消費する。この発電に伴う熱により、ブレーキ抵抗器２５の温度Ｔbは、上昇していく。 Since the road surface has a large downward gradient, negative torque is constantly generated in the electric motors ( travel motors 14L and 14R) in order to keep the vehicle speed V constant. At this time, the dump truck 1 consumes the generated power, which is the product of the torque and the rotation speeds V L and V R of the motor, as heat by the brake resistor 25. Due to the heat generated by this power generation, the temperature Tb of the brake resistor 25 rises.
　そして、ブレーキ抵抗器２５の温度Ｔbが温度Ｔ1を超過すると、前進最大速度マップＭf1に従って、前進速度制限値Ｖflimが小さくなる（時点ｔ1）。前進速度制限値Ｖflimに比べて車両速度Ｖが大きくなったとき、前進速度制限値Ｖflimに追従するように、Ａ／Ｒ信号Ｓarが減じられ、車両速度Ｖが減少する。車両速度Ｖの減少は、電動機の回転速度ＶL，ＶRの減少を意味する。そのため、電動機の発電電力は小さくなり、ブレーキ抵抗器２５での発熱も小さくなる。これにより、ブレーキ抵抗器２５の温度上昇速度は緩やかになる（時点ｔ1から時点ｔ2の区間）。 When the temperature Tb of the brake resistor 25 exceeds the temperature T1, the forward speed limit value Vflim becomes small according to the maximum forward speed map Mf1 (time point t1). When the vehicle speed V becomes larger than the forward speed limit value Vflim, the A / R signal Sar is reduced and the vehicle speed V decreases so as to follow the forward speed limit value Vflim. The decrease in the vehicle speed V means a decrease in the rotation speeds V L and V R of the electric motor. Therefore, the electric power generated by the electric motor is reduced, and the heat generated by the brake resistor 25 is also reduced. As a result, the temperature rise rate of the brake resistor 25 becomes gentle (section from time t1 to time t2).
　車両速度Ｖを低下させない場合には、図１２中の破線Ａで示すように、ブレーキ抵抗器２５の温度Ｔbは、保護温度（上限温度ＴfH）を超過してしまう。これに対し、本実施の形態によるダンプトラック１は、速度制限により車両速度Ｖを小さくしている。これにより、ブレーキ抵抗器２５の発熱が小さくなるから、最終的なブレーキ抵抗器２５の平衡温度は、保護温度以下に抑えられる（時点ｔ2から時点ｔ3の区間）。 When the vehicle speed V is not decreased, the temperature Tb of the brake resistor 25 exceeds the protection temperature (upper limit temperature TfH) as indicated by a broken line A in FIG. On the other hand, the dump truck 1 according to the present embodiment reduces the vehicle speed V due to speed limitation. As a result, the heat generated by the brake resistor 25 is reduced, so that the final equilibrium temperature of the brake resistor 25 is suppressed to the protection temperature or lower (section from time t2 to time t3).
　次に、時点ｔ3から時点ｔ4の区間では、下りの路面勾配が小さくなる。このとき、車両が下って行く方向の力が小さくなるので、電動機から出力する負のトルク（減速トルク）は小さくなる。よって、さらに発電電力が小さくなり、ブレーキ抵抗器２５の発熱もより小さくなるので、ブレーキ抵抗器２５の温度Ｔbは低下していく。 Next, in the section from time t3 to time t4, the downward road gradient becomes small. At this time, since the force in the direction in which the vehicle goes down becomes small, the negative torque (deceleration torque) output from the electric motor becomes small. Therefore, the generated power is further reduced and the heat generated by the brake resistor 25 is further reduced, so that the temperature Tb of the brake resistor 25 is lowered.
　そして、ブレーキ抵抗器２５の温度Ｔbが下限温度ＴfLよりも小さくなったとき、前進速度制限値Ｖflimは、最初の速度（最大速度Ｖfmax）まで戻る（時点ｔ5）。このとき、アクセルペダル６またはリタードペダル７の操作に応じて、車両速度Ｖを最初の速度まで戻すことが可能となる。 When the temperature Tb of the brake resistor 25 becomes lower than the lower limit temperature TfL, the forward speed limit value Vflim returns to the initial speed (maximum speed Vfmax) (time point t5). At this time, the vehicle speed V can be returned to the initial speed in accordance with the operation of the accelerator pedal 6 or the retard pedal 7.
　時点ｔ6で最初の車両速度Ｖに戻った後は、この車両速度Ｖと減少した負のトルクにより、ブレーキ抵抗器２５の発熱が決まる。このとき、ブレーキ抵抗器２５は、任意の熱平衡温度へ収束する。 After returning to the initial vehicle speed V at time t6, heat generation of the brake resistor 25 is determined by the vehicle speed V and the reduced negative torque. At this time, the brake resistor 25 converges to an arbitrary thermal equilibrium temperature.
　図１２に示すように、第１の実施の形態によるダンプトラック１では、ブレーキ抵抗器２５の温度Ｔbに応じて、前進速度制限値Ｖflimが変化する。前進速度制限値Ｖflimに対して車両速度Ｖが超過した場合に、Ａ／Ｒ信号Ｓarが減少し、車両速度Ｖが前進速度制限値Ｖflimよりも小さくなるように制御される。従って、ブレーキ抵抗器２５の温度上昇に伴い、車両速度Ｖは減少するように制御される。このとき、車両速度Ｖの減少によってブレーキ抵抗器２５の発熱が小さくなるので、最終的にはブレーキ抵抗器２５の熱平衡温度が低く抑えられる。よって、前進最大速度マップＭf1および後進最大速度マップＭr1を適切に設定すれば、ブレーキ抵抗器２５の熱平衡温度が保護温度を超過しないように、車両速度Ｖを制御することができる。 As shown in FIG. 12, in the dump truck 1 according to the first embodiment, the forward speed limit value Vflim changes according to the temperature Tb of the brake resistor 25. When the vehicle speed V exceeds the forward speed limit value Vflim, the A / R signal Sar is controlled so that the vehicle speed V becomes smaller than the forward speed limit value Vflim. Therefore, the vehicle speed V is controlled to decrease as the temperature of the brake resistor 25 increases. At this time, since the heat generation of the brake resistor 25 is reduced due to the decrease in the vehicle speed V, the thermal equilibrium temperature of the brake resistor 25 is finally kept low. Therefore, if the forward maximum speed map Mf1 and the reverse maximum speed map Mr1 are appropriately set, the vehicle speed V can be controlled so that the thermal equilibrium temperature of the brake resistor 25 does not exceed the protection temperature.
　かくして、第１の実施の形態によるダンプトラック１は、走行用モータ１４Ｌ，１４Ｒ（電動機）の速度を制御する走行装置制御部４０（コントローラ）を備えている。走行装置制御部４０は、抵抗器温度センサ３０によって取得したブレーキ抵抗器２５の温度Ｔbに基づいて、車両の最大速度（前進速度制限値Ｖflimおよび後進速度制限値Ｖrlim）を演算する速度制限演算装置４１（最大速度演算部）を備え、最大速度を超過しないように電動機の速度を制御する。 Thus, the dump truck 1 according to the first embodiment includes the traveling device control unit 40 (controller) that controls the speeds of the traveling motors 14L and 14R (electric motors). The travel device control unit 40 calculates a maximum vehicle speed (forward speed limit value Vflim and reverse speed limit value Vrlim) based on the temperature Tb of the brake resistor 25 acquired by the resistor temperature sensor 30. 41 (maximum speed calculation unit) is provided to control the speed of the motor so as not to exceed the maximum speed.
　即ち、例えばダンプトラック１の前進しているときには、速度制限演算装置４１はブレーキ抵抗器２５の温度Ｔbに応じて前進速度制限値Ｖflimを演算する。このとき、速度制限演算装置４１は、ブレーキ抵抗器２５の温度Ｔbが高くなるに従って、最大速度となる前進速度制限値Ｖflimの絶対値を低下させる。これにより、前進速度制限値Ｖflimに対して車両速度Ｖが超過した場合には、Ａ／Ｒ信号Ｓarが減少して、車両速度Ｖが前進速度制限値Ｖflimよりも小さくなるように、ダンプトラック１は制御される。そのため、ブレーキ抵抗器２５の温度Ｔbに応じて変化する前進速度制限値Ｖflimを超過しないように、車両速度Ｖは常に制限される。この点は、ダンプトラック１が後進しているときも同様である。従って、ブレーキ抵抗器２５の発電ブレーキだけで、車両速度Ｖを最小速度Ｖfmin，Ｖfminまで低下させることができ、機械ブレーキ１６を緊急時以外には使用する必要がなくなる。この結果、機械ブレーキ１６の使用頻度を抑えられるので、機械ブレーキ１６に係るメンテナンスコストを低減することができる。 That is, for example, when the dump truck 1 is moving forward, the speed limit calculation device 41 calculates the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25. At this time, the speed limit calculation device 41 decreases the absolute value of the forward speed limit value Vflim that becomes the maximum speed as the temperature Tb of the brake resistor 25 increases. Thus, when the vehicle speed V exceeds the forward speed limit value Vflim, the A / R signal Sar decreases, and the dump truck 1 is set so that the vehicle speed V becomes smaller than the forward speed limit value Vflim. Is controlled. Therefore, the vehicle speed V is always limited so as not to exceed the forward speed limit value Vflim that changes according to the temperature Tb of the brake resistor 25. This is the same when the dump truck 1 is moving backward. Therefore, the vehicle speed V can be reduced to the minimum speeds Vfmin and Vfmin only by the power generation brake of the brake resistor 25, and it is not necessary to use the mechanical brake 16 except in an emergency. As a result, since the use frequency of the mechanical brake 16 can be suppressed, the maintenance cost related to the mechanical brake 16 can be reduced.
　次に、図１３ないし図１５は本発明の第２の実施の形態を示している。第２の実施の形態の特徴は、速度制限演算装置は、ブレーキ抵抗器の温度に加えて、冷却風温度センサによって取得した冷却風の温度に基づいて、車両の最大速度を演算することにある。第２の実施の形態では、前述した第１の実施の形態と同様の構成要素に同一の符号を付し、その説明を省略するものとする。 Next, FIG. 13 to FIG. 15 show a second embodiment of the present invention. The feature of the second embodiment is that the speed limit calculating device calculates the maximum speed of the vehicle based on the temperature of the cooling air acquired by the cooling air temperature sensor in addition to the temperature of the brake resistor. . In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
　第２の実施の形態による最大速度演算部としての速度制限演算装置６１は、抵抗器温度センサ３０によって検出されたブレーキ抵抗器２５の温度Ｔbに加えて、冷却風温度センサ３１によって取得した冷却風の温度Ｔaに基づいて、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを演算する。このとき、冷却風の温度Ｔaは、冷却装置（送風機２７）の冷媒の温度である。速度制限演算装置６１は、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを、Ａ／Ｒ信号演算装置４２に出力する。 The speed limit calculation device 61 as the maximum speed calculation unit according to the second embodiment includes the cooling air temperature acquired by the cooling air temperature sensor 31 in addition to the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30. The forward speed limit value Vflim and the reverse speed limit value Vrlim are calculated based on the temperature Ta. At this time, the temperature Ta of the cooling air is the temperature of the refrigerant of the cooling device (blower 27). The speed limit calculation device 61 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
　速度制限演算装置６１は、前進最大速度となる前進速度制限値Ｖflimを演算する前進速度制限演算部６１Ａと、後進最大速度となる後進速度制限値Ｖrlimを演算する後進速度制限演算部６１Ｂとを有している。前進速度制限演算部６１Ａは、ブレーキ抵抗器２５の温度Ｔbおよび冷却風の温度Ｔaに応じて、前進速度制限値Ｖflimを出力する。具体的には、前進速度制限演算部６１Ａは、前進最大速度マップＭf2を備えている。前進最大速度マップＭf2は、ブレーキ抵抗器２５の温度Ｔbおよび冷却風の温度Ｔaに基づいて、前進速度制限値Ｖflimを演算する。 The speed limit calculation device 61 includes a forward speed limit calculation unit 61A that calculates a forward speed limit value Vflim that is a maximum forward speed, and a reverse speed limit calculation unit 61B that calculates a reverse speed limit value Vrlim that is a maximum reverse speed. doing. The forward speed limit calculation unit 61A outputs the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air. Specifically, the forward speed limit calculation unit 61A includes a forward maximum speed map Mf2. The forward maximum speed map Mf2 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air.
　前進最大速度マップＭf2は、ブレーキ抵抗器２５の温度Ｔbと前進速度制限値Ｖflimとの関係を示す特性線６１Ａ1を有している。このとき、特性線６１Ａ1は、第１の実施の形態による特性線４１Ａ1とほぼ同じである。但し、特性線６１Ａ1は、冷却風の温度Ｔaに応じて、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。具体的には、冷却風の温度Ｔaが常温（例えば２５℃）よりも上昇すると、その上昇分に応じて、特性線６１Ａ1は、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。このため、冷却風の温度Ｔaが常温よりも高くなるに従って、下限温度ＴfLは低下する。即ち、冷却風の温度Ｔaが常温よりも高いときには、冷却風の温度Ｔaが常温よりも低いときに比べて、低い下限温度ＴfLで、前進速度制限値Ｖflimは最大速度Ｖfmaxよりも低下する。また、冷却風の温度Ｔaが常温よりも高いときには、冷却風の温度Ｔaが常温よりも低いときに比べて、低い上限温度ＴfHで、前進速度制限値Ｖflimは最小速度Ｖfminに低下する。 The forward maximum speed map Mf2 has a characteristic line 61A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim. At this time, the characteristic line 61A1 is substantially the same as the characteristic line 41A1 according to the first embodiment. However, the characteristic line 61A1 shifts to the lower temperature Tb of the brake resistor 25 according to the temperature Ta of the cooling air. Specifically, when the temperature Ta of the cooling air rises above normal temperature (for example, 25 ° C.), the characteristic line 61A1 shifts to the lower temperature Tb of the brake resistor 25 according to the rise. For this reason, the lower limit temperature TfL decreases as the temperature Ta of the cooling air becomes higher than the normal temperature. That is, when the temperature Ta of the cooling air is higher than the normal temperature, the forward speed limit value Vflim is lower than the maximum speed Vfmax at a lower lower limit temperature TfL than when the temperature Ta of the cooling air is lower than the normal temperature. Further, when the cooling air temperature Ta is higher than the normal temperature, the forward speed limit value Vflim decreases to the minimum speed Vfmin at a lower upper limit temperature TfH than when the cooling air temperature Ta is lower than the normal temperature.
　また、後進速度制限演算部６１Ｂは、ブレーキ抵抗器２５の温度Ｔbおよび冷却風の温度Ｔaに応じて、後進速度制限値Ｖrlimを出力する。具体的には、後進速度制限演算部６１Ｂは、後進最大速度マップＭr2を有している。後進最大速度マップＭr2は、ブレーキ抵抗器２５の温度Ｔbおよび冷却風の温度Ｔaに基づいて、後進速度制限値Ｖrlimを演算する。後進最大速度マップＭr2は、ブレーキ抵抗器２５の温度Ｔbと後進速度制限値Ｖrlimとの関係を示す特性線６１Ｂ1を有している。このとき、特性線６１Ｂ1は、特性線６１Ａ1と同様に、冷却風の温度Ｔaが高くなるに従って、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。 Further, the reverse speed limit calculation unit 61B outputs the reverse speed limit value Vrlim according to the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air. Specifically, the reverse speed limit calculating unit 61B has a reverse maximum speed map Mr2. The reverse maximum speed map Mr2 calculates a reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 and the temperature Ta of the cooling air. The reverse maximum speed map Mr2 has a characteristic line 61B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. At this time, the characteristic line 61B1 shifts to the lower temperature Tb of the brake resistor 25 as the temperature Ta of the cooling air increases, like the characteristic line 61A1.
　かくして、このように構成された第２の実施の形態においても、前述した第１の実施の形態とほぼ同様の作用効果を得ることができる。このとき、ダンプトラック１は、ブレーキ抵抗器２５を冷却する冷却装置としての送風機２７と、冷却装置の冷媒となる冷却風の温度Ｔaを取得する冷却風温度センサ３１（冷媒温度センサ）と、を備えている。第２の実施の形態では、ブレーキ抵抗器２５の温度Ｔbに加えて、冷却風の温度Ｔaも考慮して前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを決定する。このため、周囲環境の温度が低い場合には、制限速度を高い状態に維持することによって、車両速度Ｖに制限がかかる可能性を減らすことができる。一方、周囲環境の温度が高い場合には、必要な分だけ車両速度Ｖの制限を大きくすることができる。従って、第２の実施の形態では、第１の実施の形態に比べて、幅広い周囲環境の温度で、機械ブレーキ１６の使用頻度を低減することが可能であり、機械ブレーキ１６に係るメンテナンスコストを低減することができる。 Thus, also in the second embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. At this time, the dump truck 1 includes a blower 27 as a cooling device that cools the brake resistor 25, and a cooling air temperature sensor 31 (refrigerant temperature sensor) that acquires a temperature Ta of cooling air that serves as a refrigerant of the cooling device. I have. In the second embodiment, the forward speed limit value Vflim and the reverse speed limit value Vrlim are determined in consideration of the temperature Ta of the cooling air in addition to the temperature Tb of the brake resistor 25. For this reason, when the temperature of the surrounding environment is low, the possibility that the vehicle speed V is restricted can be reduced by maintaining the speed limit at a high level. On the other hand, when the temperature of the surrounding environment is high, the limit of the vehicle speed V can be increased by a necessary amount. Therefore, in the second embodiment, compared with the first embodiment, the frequency of use of the mechanical brake 16 can be reduced at a wide range of ambient temperatures, and the maintenance cost related to the mechanical brake 16 can be reduced. Can be reduced.
　次に、図１６ないし図１８は本発明の第３の実施の形態を示している。第３の実施の形態の特徴は、速度制限演算装置は、ブレーキ抵抗器の温度に加えて、積載質量センサによって取得した車両の積載質量に基づいて、車両の最大速度を演算することにある。第３の実施の形態では、前述した第１の実施の形態と同様の構成要素に同一の符号を付し、その説明を省略するものとする。 Next, FIG. 16 to FIG. 18 show a third embodiment of the present invention. A feature of the third embodiment is that the speed limit calculation device calculates the maximum speed of the vehicle based on the load mass of the vehicle acquired by the load mass sensor in addition to the temperature of the brake resistor. In the third embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
　第３の実施の形態による最大速度演算部としての速度制限演算装置７１は、抵抗器温度センサ３０によって検出されたブレーキ抵抗器２５の温度Ｔbに加えて、積載質量センサ３２によって取得した車両の積載質量Ｗに基づいて、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを演算する。速度制限演算装置７１は、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを、Ａ／Ｒ信号演算装置４２に出力する。 The speed limit calculation device 71 as the maximum speed calculation unit according to the third embodiment includes the vehicle loading acquired by the loading mass sensor 32 in addition to the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30. Based on the mass W, the forward speed limit value Vflim and the reverse speed limit value Vrlim are calculated. The speed limit calculation device 71 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
　速度制限演算装置７１は、前進最大速度となる前進速度制限値Ｖflimを演算する前進速度制限演算部７１Ａと、後進最大速度となる後進速度制限値Ｖrlimを演算する後進速度制限演算部７１Ｂとを有している。前進速度制限演算部７１Ａは、ブレーキ抵抗器２５の温度Ｔbおよび積載質量Ｗに応じて、前進速度制限値Ｖflimを出力する。具体的には、前進速度制限演算部７１Ａは、前進最大速度マップＭf3を備えている。前進最大速度マップＭf3は、ブレーキ抵抗器２５の温度Ｔbおよび積載質量Ｗに基づいて、前進速度制限値Ｖflimを演算する。 The speed limit calculation device 71 includes a forward speed limit calculation unit 71A that calculates a forward speed limit value Vflim that is the maximum forward speed, and a reverse speed limit calculation unit 71B that calculates a reverse speed limit value Vrlim that is the maximum reverse speed. doing. The forward speed limit calculation unit 71A outputs the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25 and the loaded mass W. Specifically, the forward speed limit calculation unit 71A includes a forward maximum speed map Mf3. The forward maximum speed map Mf3 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25 and the loaded mass W.
　前進最大速度マップＭf3は、ブレーキ抵抗器２５の温度Ｔbと前進速度制限値Ｖflimとの関係を示す特性線７１Ａ1を有している。このとき、特性線７１Ａ1は、第１の実施の形態による特性線４１Ａ1とほぼ同じである。但し、特性線７１Ａ1は、積載質量Ｗに応じて、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。具体的には、積載質量Ｗが０よりも増加すると、その増加量に応じて、特性線７１Ａ1は、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。このため、積載質量Ｗが０（空荷のとき）よりも増加するに従って、下限温度ＴfLは低下する。即ち、積載質量Ｗが大きいときには、積載質量Ｗが０のときに比べて、低い下限温度ＴfLで、車両速度Ｖが制限される。また、積載質量Ｗが大きいときには、積載質量Ｗが０のときに比べて、低い上限温度ＴfHで、前進速度制限値Ｖflimは最小速度Ｖfminに低下する。 The forward maximum speed map Mf3 has a characteristic line 71A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim. At this time, the characteristic line 71A1 is substantially the same as the characteristic line 41A1 according to the first embodiment. However, the characteristic line 71A1 shifts to the lower temperature Tb of the brake resistor 25 according to the loaded mass W. Specifically, when the loading mass W increases from 0, the characteristic line 71A1 shifts to the lower temperature Tb of the brake resistor 25 according to the increase amount. For this reason, the lower limit temperature TfL decreases as the loaded mass W increases from 0 (when empty). That is, when the loading mass W is large, the vehicle speed V is limited at a lower lower limit temperature TfL than when the loading mass W is zero. Further, when the load mass W is large, the forward speed limit value Vflim is reduced to the minimum speed Vfmin at a lower upper limit temperature TfH than when the load mass W is zero.
　また、後進速度制限演算部７１Ｂは、ブレーキ抵抗器２５の温度Ｔbおよび積載質量Ｗに応じて、後進速度制限値Ｖrlimを出力する。具体的には、後進速度制限演算部７１Ｂは、後進最大速度マップＭr3を有している。後進最大速度マップＭr3は、ブレーキ抵抗器２５の温度Ｔbおよび積載質量Ｗに基づいて、後進速度制限値Ｖrlimを演算する。後進最大速度マップＭr3は、ブレーキ抵抗器２５の温度Ｔbと後進速度制限値Ｖrlimとの関係を示す特性線７１Ｂ1を有している。このとき、特性線７１Ｂ1は、特性線７１Ａ1と同様に、積載質量Ｗが大きくなるに従って、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。 Further, the reverse speed limit calculation unit 71B outputs the reverse speed limit value Vrlim according to the temperature Tb and the load mass W of the brake resistor 25. Specifically, the reverse speed limit calculation unit 71B has a reverse maximum speed map Mr3. The reverse maximum speed map Mr3 calculates a reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 and the loaded mass W. The reverse maximum speed map Mr3 has a characteristic line 71B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. At this time, similarly to the characteristic line 71A1, the characteristic line 71B1 shifts to the lower temperature Tb of the brake resistor 25 as the loaded mass W increases.
　かくして、このように構成された第３の実施の形態においても、前述した第１の実施の形態とほぼ同様の作用効果を得ることができる。例えばベッセル３に積載物を満載した場合には、空荷（Ｗ＝０）のときに比べて、走行状態の車両を停止させるときにブレーキ抵抗器２５で消費するエネルギが増加する。これに対し、ダンプトラック１は、車両の積載質量Ｗを取得する積載質量センサ３２を備えている。第３の実施の形態では、ブレーキ抵抗器２５の温度Ｔbに加えて、積載質量Ｗも考慮して前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを決定する。このため、ダンプトラック１のように、積載状況に応じてブレーキ抵抗器２５の消費電力が大きく異なる車両であっても、空荷の場合には、制限速度を高い状態に維持することによって、車両速度Ｖに制限がかかる可能性を減らすことができる。一方、ベッセル３に積載物を満載した場合には、必要な分だけ車両速度Ｖの制限を大きくすることができる。従って、第３の実施の形態では、第１の実施の形態に比べて、車両の積載状況に応じて、機械ブレーキ１６の使用頻度を低減することが可能であり、機械ブレーキ１６に係るメンテナンスコストを低減することができる。 Thus, also in the third embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. For example, when the vessel 3 is fully loaded, the energy consumed by the brake resistor 25 when stopping the running vehicle is increased as compared with the case of empty load (W = 0). On the other hand, the dump truck 1 includes a loading mass sensor 32 that acquires the loading mass W of the vehicle. In the third embodiment, the forward speed limit value Vflim and the reverse speed limit value Vrlim are determined in consideration of the load mass W in addition to the temperature Tb of the brake resistor 25. For this reason, even if the power consumption of the brake resistor 25 differs greatly depending on the loading situation, such as the dump truck 1, in the case of an empty load, the vehicle is maintained by maintaining the speed limit high. The possibility that the speed V is limited can be reduced. On the other hand, when the load is fully loaded on the vessel 3, the limit of the vehicle speed V can be increased by a necessary amount. Therefore, in the third embodiment, compared to the first embodiment, the frequency of use of the mechanical brake 16 can be reduced according to the loading situation of the vehicle, and the maintenance cost related to the mechanical brake 16 is reduced. Can be reduced.
　次に、図１９ないし図２１は本発明の第４の実施の形態を示している。第４の実施の形態の特徴は、速度制限演算装置は、ブレーキ抵抗器の温度に加えて、路面勾配センサによって取得した路面の勾配に基づいて、車両の最大速度を演算することにある。第４の実施の形態では、前述した第１の実施の形態と同様の構成要素に同一の符号を付し、その説明を省略するものとする。 Next, FIG. 19 to FIG. 21 show a fourth embodiment of the present invention. A feature of the fourth embodiment is that the speed limit calculation device calculates the maximum speed of the vehicle based on the road surface gradient acquired by the road surface gradient sensor in addition to the temperature of the brake resistor. In the fourth embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
　第４の実施の形態による最大速度演算部としての速度制限演算装置８１は、抵抗器温度センサ３０によって検出されたブレーキ抵抗器２５の温度Ｔbに加えて、路面勾配センサ３３によって取得した路面の勾配θに基づいて、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを演算する。速度制限演算装置８１は、前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを、Ａ／Ｒ信号演算装置４２に出力する。 In addition to the temperature Tb of the brake resistor 25 detected by the resistor temperature sensor 30, the speed limit calculating device 81 as the maximum speed calculating unit according to the fourth embodiment adds the road surface gradient acquired by the road surface gradient sensor 33. Based on θ, the forward speed limit value Vflim and the reverse speed limit value Vrlim are calculated. The speed limit calculation device 81 outputs the forward speed limit value Vflim and the reverse speed limit value Vrlim to the A / R signal calculation device 42.
　速度制限演算装置８１は、前進最大速度となる前進速度制限値Ｖflimを演算する前進速度制限演算部８１Ａと、後進最大速度となる後進速度制限値Ｖrlimを演算する後進速度制限演算部８１Ｂとを有している。前進速度制限演算部８１Ａは、ブレーキ抵抗器２５の温度Ｔbおよび路面の勾配θに応じて、前進速度制限値Ｖflimを出力する。具体的には、前進速度制限演算部８１Ａは、前進最大速度マップＭf4を備えている。前進最大速度マップＭf4は、ブレーキ抵抗器２５の温度Ｔbおよび路面の勾配θに基づいて、前進速度制限値Ｖflimを演算する。 The speed limit calculation device 81 includes a forward speed limit calculation unit 81A that calculates a forward speed limit value Vflim that is a maximum forward speed, and a reverse speed limit calculation unit 81B that calculates a reverse speed limit value Vrlim that is a maximum reverse speed. doing. The forward speed limit calculation unit 81A outputs the forward speed limit value Vflim according to the temperature Tb of the brake resistor 25 and the road surface gradient θ. Specifically, the forward speed limit calculation unit 81A includes a forward maximum speed map Mf4. The maximum forward speed map Mf4 calculates the forward speed limit value Vflim based on the temperature Tb of the brake resistor 25 and the road surface gradient θ.
　前進最大速度マップＭf4は、ブレーキ抵抗器２５の温度Ｔbと前進速度制限値Ｖflimとの関係を示す特性線８１Ａ1を有している。このとき、特性線８１Ａ1は、第１の実施の形態による特性線４１Ａ1とほぼ同じである。但し、特性線８１Ａ1は、路面の勾配θに応じて、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。具体的には、路面の勾配θが下り勾配方向で増加すると、その増加量に応じて、特性線８１Ａ1は、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。このため、路面の勾配θが平坦路よりも下り勾配方向で増加するに従って、下限温度ＴfLは低下する。即ち、下り勾配が大きいときには、平坦路に比べて、低い下限温度ＴfLで、車両速度Ｖが制限される。また、下り勾配が大きいときには、平坦路に比べて、低い上限温度ＴfHで、前進速度制限値Ｖflimは最小速度Ｖfminに低下する。 The forward maximum speed map Mf4 has a characteristic line 81A1 indicating the relationship between the temperature Tb of the brake resistor 25 and the forward speed limit value Vflim. At this time, the characteristic line 81A1 is substantially the same as the characteristic line 41A1 according to the first embodiment. However, the characteristic line 81A1 shifts to the lower temperature Tb of the brake resistor 25 in accordance with the road surface gradient θ. Specifically, when the road surface gradient θ increases in the downward gradient direction, the characteristic line 81A1 shifts to the lower temperature Tb of the brake resistor 25 according to the increase amount. Therefore, the lower limit temperature TfL decreases as the road surface gradient θ increases in the downward gradient direction than the flat road. That is, when the downward gradient is large, the vehicle speed V is limited at a lower lower limit temperature TfL compared to a flat road. On the other hand, when the descending slope is large, the forward speed limit value Vflim decreases to the minimum speed Vfmin at a lower upper limit temperature TfH compared to a flat road.
　また、後進速度制限演算部８１Ｂは、ブレーキ抵抗器２５の温度Ｔbおよび路面の勾配θに応じて、後進速度制限値Ｖrlimを出力する。具体的には、後進速度制限演算部８１Ｂは、後進最大速度マップＭr4を有している。後進最大速度マップＭr4は、ブレーキ抵抗器２５の温度Ｔbおよび路面の勾配θに基づいて、後進速度制限値Ｖrlimを演算する。後進最大速度マップＭr4は、ブレーキ抵抗器２５の温度Ｔbと後進速度制限値Ｖrlimとの関係を示す特性線８１Ｂ1を有している。このとき、特性線８１Ｂ1は、特性線８１Ａ1と同様に、下り勾配が大きくなるに従って、ブレーキ抵抗器２５の温度Ｔbが低い方にシフトする。 Also, the reverse speed limit calculation unit 81B outputs the reverse speed limit value Vrlim according to the temperature Tb of the brake resistor 25 and the road surface gradient θ. Specifically, the reverse speed limit calculation unit 81B has a reverse maximum speed map Mr4. The reverse maximum speed map Mr4 calculates the reverse speed limit value Vrlim based on the temperature Tb of the brake resistor 25 and the road surface gradient θ. The reverse maximum speed map Mr4 has a characteristic line 81B1 indicating the relationship between the temperature Tb of the brake resistor 25 and the reverse speed limit value Vrlim. At this time, the characteristic line 81B1 shifts to the lower temperature Tb of the brake resistor 25 as the descending slope becomes larger, like the characteristic line 81A1.
　かくして、このように構成された第４の実施の形態においても、前述した第１の実施の形態とほぼ同様の作用効果を得ることができる。例えば下り勾配の場合には、平坦路に比べて、走行状態の車両を停止させるときにブレーキ抵抗器２５で消費するエネルギが増加する。これに対し、ダンプトラック１は、車両の後輪９Ｌ，９Ｒ（駆動輪）が接地する路面の勾配θを取得する路面勾配センサ３３を備えている。第４の実施の形態では、ブレーキ抵抗器２５の温度Ｔbに加えて、路面の勾配θも考慮して前進速度制限値Ｖflimと後進速度制限値Ｖrlimとを決定する。このため、例えば上り勾配や平坦路の場合には、制限速度を高い状態に維持することによって、車両速度Ｖに制限がかかる可能性を減らすことができる。一方、下り勾配の場合には、必要な分だけ車両速度Ｖの制限を大きくすることができる。従って、第４の実施の形態では、第１の実施の形態に比べて、幅広い路面の勾配状況に応じて、機械ブレーキ１６の使用頻度を低減することが可能であり、機械ブレーキ１６に係るメンテナンスコストを低減することができる。 Thus, also in the fourth embodiment configured as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment described above. For example, in the case of a downward slope, the energy consumed by the brake resistor 25 when stopping a vehicle in a running state is increased as compared with a flat road. On the other hand, the dump truck 1 is provided with a road surface gradient sensor 33 that acquires a gradient θ of the road surface on which the rear wheels 9L and 9R (drive wheels) of the vehicle come into contact. In the fourth embodiment, the forward speed limit value Vflim and the reverse speed limit value Vrlim are determined in consideration of the road surface gradient θ in addition to the temperature Tb of the brake resistor 25. For this reason, for example, in the case of an ascending slope or a flat road, the possibility that the vehicle speed V is restricted can be reduced by maintaining the speed limit at a high level. On the other hand, in the case of a downward slope, the limit of the vehicle speed V can be increased by a necessary amount. Therefore, in the fourth embodiment, it is possible to reduce the frequency of use of the mechanical brake 16 in accordance with a wide range of road surface gradient conditions as compared with the first embodiment, and maintenance related to the mechanical brake 16 is possible. Cost can be reduced.
　なお、前記各実施の形態では、電気駆動車両としてダンプトラック１を例に挙げて説明した。本発明はこれに限らず、電動機によって走行駆動し、回生制動が可能な電気駆動車両であればよく、例えばホイールローダに適用してもよい。 In each of the above embodiments, the dump truck 1 has been described as an example of the electrically driven vehicle. The present invention is not limited to this, and any electric drive vehicle that can be driven and driven by an electric motor and capable of regenerative braking may be used. For example, the present invention may be applied to a wheel loader.
　また、前記各実施の形態で記載した周波数等の具体的な数値は、一例を示したものであり、例示した値に限らない。これらの数値は、例えば適用対象の仕様に応じて適宜設定される。 In addition, specific numerical values such as frequencies described in the respective embodiments are merely examples, and are not limited to the illustrated values. These numerical values are appropriately set according to, for example, the specification to be applied.
　前記各実施の形態は例示であり、異なる実施の形態で示した構成の部分的な置換または組み合わせが可能であることは言うまでもない。 The above embodiments are merely examples, and it is needless to say that partial replacement or combination of the configurations shown in the different embodiments is possible.
　１　ダンプトラック
　６　アクセルペダル
　６Ａ　アクセルペダル開度センサ
　７　リタードペダル
　７Ａ　リタードペダル開度センサ
　８Ｌ，８Ｒ　前輪
　９Ｌ，９Ｒ　後輪
　１４Ｌ，１４Ｒ　走行用モータ（電動機）
　１６　機械ブレーキ
　１８Ｌ，１８Ｒ　速度センサ（車両速度センサ）
　１９Ｌ，１９Ｒ　電流センサ
　２４Ｌ，２４Ｒ　インバータ
　２５　ブレーキ抵抗器
　２７　送風機（冷却装置）
　３０　抵抗器温度センサ
　３１　冷却風温度センサ（冷媒温度センサ）
　３２　積載質量センサ
　３３　路面勾配センサ
　４０　走行装置制御部（コントローラ）
　４１，６１，７１，８１　速度制限演算装置（最大速度演算部） 1 Dump Truck 6 Accelerator Pedal 6A Accelerator Pedal Opening Sensor 7 Retarded Pedal 7A Retarded Pedal Opening Sensor 8L, 8R Front Wheel 9L, 9R Rear Wheel 14L, 14R Driving Motor (Electric Motor)
16 Mechanical brake 18L, 18R Speed sensor (vehicle speed sensor)
19L, 19R Current sensor 24L, 24R Inverter 25 Brake resistor 27 Blower (cooling device)
30 Resistor temperature sensor 31 Cooling air temperature sensor (refrigerant temperature sensor)
32 Load mass sensor 33 Road surface gradient sensor 40 Traveling device controller (controller)
41, 61, 71, 81 Speed limit calculation device (maximum speed calculation unit)

Claims (5)

  1. 　電動機と、
    　前記電動機を制御するインバータと、
    　前記電動機により駆動される駆動輪と、
    　リタードペダルの操作に応じて前記電動機を回生制御するときに発電された電力を熱として消費するブレーキ抵抗器と、
    　前記ブレーキ抵抗器の温度を取得する抵抗器温度センサと、
    　車両の速度を取得する車両速度センサと、
    　前記インバータを用いて前記電動機の速度を制御するコントローラと、を備えた電気駆動車両において、
    　前記コントローラは、前記抵抗器温度センサによって取得した前記ブレーキ抵抗器の温度に基づいて、前記車両の最大速度を演算する最大速度演算部を備え、
    　前記最大速度を超過しないように前記電動機の速度を制御することを特徴とする電気駆動車両。     An electric motor,
    An inverter for controlling the electric motor;
    Drive wheels driven by the electric motor;
    A brake resistor that consumes the generated electric power as heat when regeneratively controlling the electric motor according to the operation of the retard pedal;
    A resistor temperature sensor for obtaining a temperature of the brake resistor;
    A vehicle speed sensor for acquiring the speed of the vehicle;
    A controller for controlling the speed of the electric motor using the inverter;
    The controller includes a maximum speed calculation unit that calculates the maximum speed of the vehicle based on the temperature of the brake resistor acquired by the resistor temperature sensor,
    An electric drive vehicle characterized by controlling a speed of the electric motor so as not to exceed the maximum speed.
  2. 　前記最大速度演算部は、前記ブレーキ抵抗器の温度が高くなるに従って、前記車両の最大速度を低下させることを特徴とする請求項１に記載の電気駆動車両。 The electric drive vehicle according to claim 1, wherein the maximum speed calculation unit decreases the maximum speed of the vehicle as the temperature of the brake resistor increases.
  3. 　前記ブレーキ抵抗器を冷却する冷却装置と、
    　前記冷却装置の冷媒の温度を取得する冷媒温度センサと、を備え、
    　前記最大速度演算部は、前記ブレーキ抵抗器の温度に加えて、前記冷媒温度センサによって取得した前記冷却装置の冷媒の温度に基づいて、前記車両の最大速度を演算することを特徴とする請求項１に記載の電気駆動車両。     A cooling device for cooling the brake resistor;
    A refrigerant temperature sensor that acquires a temperature of the refrigerant of the cooling device, and
    The said maximum speed calculating part calculates the maximum speed of the said vehicle based on the temperature of the refrigerant | coolant of the said cooling device acquired with the said refrigerant temperature sensor in addition to the temperature of the said brake resistor. The electric drive vehicle according to 1.
  4. 　前記車両の積載質量を取得する積載質量センサを備え、
    　前記最大速度演算部は、前記ブレーキ抵抗器の温度に加えて、前記積載質量センサによって取得した前記車両の積載質量に基づいて、前記車両の最大速度を演算することを特徴とする請求項１に記載の電気駆動車両。     A loading mass sensor for obtaining the loading mass of the vehicle;
    The said maximum speed calculating part calculates the maximum speed of the said vehicle based on the loading mass of the said vehicle acquired by the said loading mass sensor in addition to the temperature of the said brake resistor. The electrically driven vehicle described.
  5. 　前記車両の駆動輪が接地する路面の勾配を取得する路面勾配センサを備え、
    　前記最大速度演算部は、前記ブレーキ抵抗器の温度に加えて、前記路面勾配センサによって取得した前記路面の勾配に基づいて、前記車両の最大速度を演算することを特徴とする請求項１に記載の電気駆動車両。     A road surface gradient sensor for obtaining a gradient of a road surface on which the driving wheel of the vehicle contacts the ground;
    The said maximum speed calculating part calculates the maximum speed of the said vehicle based on the gradient of the said road surface acquired by the said road surface gradient sensor in addition to the temperature of the said brake resistor. Electric drive vehicle.
PCT/JP2018/006442 2018-02-22 2018-02-22 Electrically driven vehicle WO2019163052A1 (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112406826A (en) * 2020-12-07 2021-02-26 广州电力机车有限公司 Control strategy for electric drive dumper braking system
CN112863791A (en) * 2021-03-05 2021-05-28 广州市市政集团有限公司 Electric locomotive brake resistance temperature control device
JP2022044441A (en) * 2020-09-07 2022-03-17 株式会社ダイフク Article conveyance facility
US20230166601A1 (en) * 2021-11-29 2023-06-01 Caterpillar Global Mining Equipment Llc Brake control system for battery-powered machine
WO2023234091A1 (en) * 2022-05-31 2023-12-07 株式会社小松製作所 Dump truck
WO2024095707A1 (en) * 2022-10-31 2024-05-10 株式会社デンソー Vehicle control device, and program

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003532583A (en) * 2000-05-02 2003-11-05 ボルボ アーティキュレイテッド ホーラーズ アーベー Apparatus and method for determining maximum allowable speed of a vehicle
JP2008533956A (en) * 2005-02-28 2008-08-21 キャタピラー インコーポレイテッド Gradient limited retard control for propulsion machines
JP2015140767A (en) * 2014-01-30 2015-08-03 日立建機株式会社 Work vehicle prime mover control device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003532583A (en) * 2000-05-02 2003-11-05 ボルボ アーティキュレイテッド ホーラーズ アーベー Apparatus and method for determining maximum allowable speed of a vehicle
JP2008533956A (en) * 2005-02-28 2008-08-21 キャタピラー インコーポレイテッド Gradient limited retard control for propulsion machines
JP2015140767A (en) * 2014-01-30 2015-08-03 日立建機株式会社 Work vehicle prime mover control device

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022044441A (en) * 2020-09-07 2022-03-17 株式会社ダイフク Article conveyance facility
JP7400668B2 (en) 2020-09-07 2023-12-19 株式会社ダイフク Goods conveyance equipment
US11897698B2 (en) 2020-09-07 2024-02-13 Daifuku Co., Ltd. Article transport facility
CN112406826A (en) * 2020-12-07 2021-02-26 广州电力机车有限公司 Control strategy for electric drive dumper braking system
CN112406826B (en) * 2020-12-07 2022-04-05 广州电力机车有限公司 Control strategy for electric drive dumper braking system
CN112863791A (en) * 2021-03-05 2021-05-28 广州市市政集团有限公司 Electric locomotive brake resistance temperature control device
JP2022135818A (en) * 2021-03-05 2022-09-15 広州市市政集団有限公司 Electric locomotive brake resistor temperature control device
US20230166601A1 (en) * 2021-11-29 2023-06-01 Caterpillar Global Mining Equipment Llc Brake control system for battery-powered machine
US12077065B2 (en) * 2021-11-29 2024-09-03 Caterpillar Global Mining Equipment Llc Brake control system for battery-powered machine
WO2023234091A1 (en) * 2022-05-31 2023-12-07 株式会社小松製作所 Dump truck
WO2024095707A1 (en) * 2022-10-31 2024-05-10 株式会社デンソー Vehicle control device, and program

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