JP5702100B2 - Work vehicle control system - Google Patents

Description

  The present invention provides a control means for controlling the engine output rotational speed so that the set rotational speed set by the setting means can be obtained, so that the engine output is controlled so that the rotational speed of the PTO shaft does not exceed a preset maximum rotational speed. A working vehicle is provided with a limiting means for limiting the rotational speed, and the limiting means is configured to switch between an execution state for limiting the output rotational speed of the engine and a non-restricted stop state based on an output from the command means. It relates to the control system.

  The work vehicle control system as described above is based on an overload of a working device that operates with power from the PTO shaft by limiting the output rotational speed of the engine so that the rotational speed of the PTO shaft does not exceed the maximum rotational speed. Prevents damage.

  As a work vehicle control system as described above, a setting means for setting the engine speed, and a controller for controlling the engine so as to be the speed set by the setting means (the set speed) (described above) Control unit), a PTO shaft rotational speed setting means for setting an upper limit value of the rotational speed of the PTO shaft (the above-mentioned maximum rotational speed), and a means for detecting the rotational speed of the engine output shaft, Whether the engine is controlled so that the PTO shaft rotation speed does not exceed the upper limit even if the setting means is operated to exceed the upper limit value of the PTO shaft rotation speed. There is one provided with means for switching whether to restrict (corresponding to the above-mentioned command means) (for example, see Patent Document 1).

JP 2006-299902 A

  In the above configuration, for example, in a state where the set rotational speed set by the setting means greatly exceeds the engine rotational speed corresponding to the maximum rotational speed of the PTO shaft, the rotational speed of the PTO shaft exceeds the maximum rotational speed by the command means. If the engine output speed is switched from a state where the engine output speed is limited to a state where the engine output speed is not limited, the engine output speed may suddenly increase from the engine speed corresponding to the maximum speed of the PTO shaft to the set speed. There is room for improvement in controlling the engine output speed.

  The object of the present invention is to prevent the occurrence of inconvenience that the vehicle body suddenly accelerates when the engine output speed is switched from a state where the engine output speed is limited so as not to exceed the maximum speed. There is in doing so.

In the first problem solving means of the present invention,
The engine output speed is limited to control means for controlling the engine output speed so that the set speed set by the setting means can be obtained so that the PTO shaft speed does not exceed a preset maximum speed. A control system for a work vehicle configured to switch between an execution state for limiting the output speed of the engine and a stop state for not limiting based on an output from the command means.
When the control means switches from the execution state to the stop state in a state where the set speed exceeds the engine speed limit corresponding to the maximum speed, the switching is performed. A sudden rise prevention means for preventing a sudden rise in the output speed of the engine accompanying the
The sudden rise prevention means compares the set rotational speed with the limited rotational speed when the limiting means switches from the execution state to the stopped state, and the set rotational speed exceeds the limited rotational speed. And, unless the set rotational speed is changed to be equal to or lower than the limit rotational speed by the operation of the setting means, the engine output rotational speed is limited so that the engine rotational speed does not exceed the limit rotational speed, When the setting rotational speed is set to be less than or equal to the limit rotational speed by the operation of the setting means, the restriction on the output rotational speed of the engine is canceled and the set rotational speed exceeds the limit rotational speed. Thus, the engine output rotational speed is allowed to exceed the limit rotational speed.

According to this problem solving means, for example, in a state where the set rotational speed greatly exceeds the engine speed limit corresponding to the maximum rotational speed of the PTO shaft, the limiting means stops from the execution state based on the output from the command means. Even in the case of switching to the state, it is possible to avoid the possibility that the output rotational speed of the engine suddenly increases from the limited rotational speed to the set rotational speed.
Therefore, it is possible to prevent the inconvenience of sudden acceleration of the vehicle body when switching from the state where the engine output rotational speed is limited to the state where it is not limited so that the rotational speed of the PTO shaft does not exceed the maximum rotational speed.

In the second problem solving means of the present invention, in the first problem solving means,
A PTO clutch for intermittently transmitting power from the engine to the PTO shaft by the control operation of the control means;
The command means commands the PTO clutch to be engaged / disconnected, and the control means switches the PTO clutch to the connected state based on the PTO clutch connection command from the command means, and the restricting means switches to the execution state. Further, the control means switches the PTO clutch to the disconnected state based on the PTO clutch disconnection command from the command means, and the limiting means switches to the stopped state.

  According to this problem solving means, when the command means outputs a connection command for the PTO clutch, the PTO clutch is switched to the connected state and the limiting means is switched to the execution state so that the rotational speed of the PTO shaft does not exceed the maximum rotational speed. The limiting means limits the engine output speed. When the command means outputs a PTO clutch shut-off command, the PTO clutch is switched to the shut-off state and the limiting means is switched to the stop state, and the limiting means does not limit the engine output speed.

  That is, the PTO switch for commanding the engagement of the PTO clutch, the operation position of the PTO clutch lever, or the detection means for detecting the engagement state of the PTO clutch can also be used as the command means. Compared with the case where a dedicated command means for commanding switching is provided, it is possible to improve operability and reduce costs.

  In this way, the PTO clutch can be switched between the execution state and the stop state of the PTO clutch along with the PTO clutch on / off operation based on the operation of the PTO switch and the PTO clutch lever. When the means is switched to the stop state, it is possible to avoid the possibility that the engine output speed unexpectedly suddenly increases from the engine speed limit corresponding to the maximum speed of the PTO shaft to the set speed. be able to.

  Therefore, it is possible to prevent the inconvenience that the vehicle body suddenly accelerates with the PTO clutch disengagement operation while improving the operability and reducing the cost.

In the third problem solving means of the present invention, in the second problem solving means,
A detecting means for detecting the output rotational speed of the engine;
The control means compares the output of the detection means with the limit rotational speed based on the PTO clutch connection command from the command means, and if the output of the detection means exceeds the limit rotational speed, The PTO clutch is maintained in the disengaged state, and the PTO clutch is switched to the connected state when the output of the detecting means is equal to or lower than the limit rotational speed.

  According to this problem solving means, even when a command for connecting the PTO clutch is output from the command means when the output speed of the engine output from the detection means exceeds the limit speed, the PTO clutch is operated based on the connection command. The engine does not immediately switch to the connected state, but the control operation of the limiting unit that switches to the running state based on the connection command causes the PTO to decrease as the engine output rotational speed output by the detecting unit decreases to the limited rotational speed. The clutch is switched to the connected state.

  That is, while the engine is configured to switch between the execution state and the stop state of the limiting means together with the PTO clutch on / off operation based on the operation of the PTO switch or the PTO clutch lever, the engine output rotational speed is set to the limited rotational speed. It is possible to prevent the PTO clutch from switching to the connected state based on the connection command of the PTO clutch from the command means when exceeding.

  Therefore, while improving the operability and reducing the cost, the working device operating with the power from the PTO shaft is damaged due to overload due to the rotation speed of the PTO shaft exceeding the maximum rotation speed. Can be prevented.

It is the whole left side view of a tractor. It is a block diagram which shows the transmission structure of a tractor. It is a block diagram which shows the control structure of a tractor. It is a figure which shows the flow of control in PTO clutch control. It is a figure which shows the flow of control in restriction | limiting control. It is a figure which shows the flow of control in sudden rise prevention control. It is a figure which shows the relationship between operation of a PTO switch, the output rotation speed of an engine, and the rotation speed of a PTO shaft. It is a figure which shows the relationship between operation of the PTO switch in a comparative example, the output rotation speed of an engine, and the rotation speed of a PTO shaft.

  Hereinafter, as an example of an embodiment for carrying out the present invention, an embodiment in which a work vehicle control system according to the present invention is applied to a tractor that is an example of a work vehicle will be described with reference to the drawings.

  As shown in FIG. 1, the tractor is equipped with a water-cooled engine 2 and a radiator 3 mounted on a front frame 1 provided at the front thereof, and a transmission case (hereinafter referred to as T / M) provided at the rear thereof. A boarding operation unit 5 is formed above the front frame 1, and a pair of left and right front wheels 6 as steering wheels capable of being driven by power from the engine 2 are provided on the left and right sides of the front frame 1. A pair of left and right rear wheels 7 as drive wheels driven by power from the engine 2 are provided on the left and right sides of the rear part of the case 4 to form a four-wheel drive type.

  The boarding operation unit 5 includes a steering wheel 8 and a driver seat 9 that are linked to the left and right front wheels 6 and a cabin 10 that forms a boarding operation space.

  At the rear of the T / M case 4 are a pair of left and right lift arms 12 that are hydraulically moved up and down by the action of a pair of left and right lift cylinders 11, and a PTO shaft that allows the power from the engine 2 to be taken out to the outside. 13 etc. are equipped. As a result, the tractor can be connected to a rear portion of a working device (not shown) such as a rotary tiller or plow so that it can be driven up and down, and is used for working on a drive-type working device such as a rotary tiller. The power can be taken out.

  As shown in FIG. 2, in this tractor, the power from the engine 2 is transmitted via a damper 14 to an input shaft 15A of an electrohydraulic control type forward / reverse switching device 15 that also serves as a travel clutch. Then, the forward power or the reverse power after switching by the forward / reverse switching device 15 taken out from the output shaft 15B of the forward / reverse switching device 15 is used for traveling as an electrohydraulic control type main transmission 16 and synchromesh type sub-shift. Gears are shifted by the device 17, and the motive power after shifting by them is transmitted to the left and right rear wheels 7 via a differential device 18 for the rear wheels and the electrohydraulic control front wheel drive switching device 19. And, it is transmitted to the left and right front wheels 6 via the differential device 20 for the front wheels. Further, the power from the engine 2 taken out from the input shaft 15A of the forward / reverse switching device 15 is transmitted to the PTO shaft 13 through the electrohydraulic control type PTO clutch 21 and the synchromesh type PTO transmission 22 for work. .

  As shown in FIG. 3, the engine 2 operates with an accelerator cylinder 24 that operates a speed control lever 23 of a speed governor (not shown), and the output speed is set between an idling speed and a rated speed. Can be adjusted steplessly. An electric cylinder is adopted as the accelerator cylinder 24. The operation of the accelerator cylinder 24 is controlled by a control operation of an accelerator control means 25A provided as a control program in an electronic control unit (hereinafter referred to as ECU) 25 that functions as a control means.

  The ECU 25 is configured using a microcomputer provided with a CPU, an EEPROM, and the like. The ECU 25 includes an engine as detection means for detecting the output of the lever sensor 27 for detecting the operation position of the accelerator lever 26, the output of the pedal sensor 29 for detecting the operation position of the accelerator pedal 28, and the output rotational speed of the engine 2. The output of the sensor 30 is input. Further, the first data for setting the engine speed indicating the relationship between the operating position of the accelerator lever 26 and the output speed of the engine 2 and the relationship between the operating position of the accelerator pedal 28 and the output speed of the engine 2 are shown. Second data for setting the engine speed is provided.

  The accelerator lever 26 is configured as a position-holding type and is disposed on the lower right side of the steering wheel 8. The accelerator pedal 28 is configured in a self-return type that automatically returns to the depression release position, and is provided at the right foot portion of the boarding operation unit 5. A rotary potentiometer is employed for the lever sensor 27 for the accelerator lever and the pedal sensor 29 for the accelerator pedal. The engine sensor 30 employs an electromagnetic pickup type rotation sensor. Map data, a relational expression, etc. are employable as 1st data and 2nd data.

  The accelerator control means 25A performs accelerator control based on the output of the lever sensor 27 for the accelerator lever, the output of the pedal sensor 29 for the accelerator pedal, the output of the engine sensor 30, and the like. Specifically, based on the output of the lever sensor 27 for the accelerator lever, the output of the pedal sensor 29 for the accelerator pedal, the first data, and the second data, the set rotational speed corresponding to the operation position of the accelerator lever 26 and The set rotation speed corresponding to the operation position of the accelerator pedal 28 is obtained, and the obtained set rotation speed by the accelerator lever 26 and the set rotation speed by the accelerator pedal 28 are compared. When the set rotational speed by the accelerator pedal 28 is equal to or lower than the set rotational speed by the accelerator lever 26, the set rotational speed by the accelerator lever 26 is adopted as the target rotational speed. When the set rotational speed by the accelerator pedal 28 is higher than the set rotational speed by the accelerator lever 26, the set rotational speed by the accelerator pedal 28 is adopted as the target rotational speed. Then, the operation of the accelerator cylinder 24 is controlled so that the output of the engine sensor 30 matches the adopted target rotational speed (within the dead band width of the target rotational speed).

  In other words, in this embodiment, the accelerator lever 26 and the lever sensor 27 constitute the setting means A for setting the set rotational speed of the engine 2 by lever operation, and the accelerator pedal 28 and the pedal sensor 29 operate the engine by pedal operation. The setting means A for setting the set rotational speed 2 is configured.

  As shown in FIG. 3, the PTO clutch 21 is in a connected state in which power from the engine 2 is transmitted to the PTO shaft 13 via the PTO transmission 22 by operation of a clutch valve 31 configured using an electromagnetic control valve. , And switch to a shut-off state that cuts off the transmission. The operation of the clutch valve 31 is controlled by the control operation of the PTO clutch control means 25B provided in the ECU 25 as a control program. The PTO clutch 21 is a multi-plate hydraulic clutch.

  The ECU 25 is supplied with the output of the PTO switch 32 that commands the on / off of the PTO clutch 21 and the output of the arm sensor 33 that detects the swing angle of the lift arm 12 as the height of the working device.

  The PTO switch 32 is disposed at the right side of the driver's seat 9 in the boarding driver 5. The PTO switch 32 has an “automatic” position in which an “off” position for commanding disconnection of the PTO clutch 21, an “on” position for commanding connection of the PTO clutch 21, and an output of the arm sensor 33 are used as the on / off command for the PTO clutch 21. A dial-type multi-contact switch configured to return to the “OFF” position by a downward pressing operation with a three-position switching type that can be switched between and is adopted. The arm sensor 33 employs a rotary potentiometer.

  As shown in FIG. 4, the PTO clutch control means 25B performs PTO clutch control for intermittently operating the PTO clutch 21 based on the output of the PTO switch 32 or the like. Basically, the operation position of the PTO switch 32 is determined based on the output of the PTO switch 32 [# 1, # 2]. When the operation position of the PTO switch 32 is the “ON” position, the output of the PTO switch 32 at this time is received as a connection command, and the clutch valve is set so that the PTO clutch 21 enters the connection state based on this connection command. The operation of 31 is controlled [# 5]. When the operation position of the PTO switch 32 is the “off” position, the output of the PTO switch 32 at this time is received as a disconnection command, and the clutch valve 31 is set so that the PTO clutch 21 is in a disconnected state based on the disconnection command. The operation is controlled [# 6]. When the operation position of the PTO switch 32 is the “automatic” position, the output of the arm sensor 33 is used as an on / off command for the PTO clutch 21 and the swing angle of the lift arm 12 output by the arm sensor 33 is less than the set angle. Within the angle region, the output of the arm sensor 33 at this time is received as a connection command, and the lift arm 12 output by the arm sensor 33 so that the PTO clutch 21 is in a connected state based on this connection command. If the swing angle is within the angle range above the set angle, the output of the arm sensor 33 at this time is received as a shutoff command, and the PTO clutch 21 is shut off based on this shutoff command. The operation of the valve 31 is controlled [# 3, # 5, # 6].

  That is, when a grounding type work device such as a rotary tiller that operates with power from the PTO shaft 13 is connected as the work device, by operating the PTO switch 32 to the “automatic” position, The work device can be operated in conjunction with the swing angle of the lift arm 12 being less than the set angle by the lowering operation of the work device. In addition, the operation of the work device can be stopped in conjunction with the swing angle of the lift arm 12 being greater than or equal to the set angle by the raising operation of the work device.

  Although not shown, the PTO transmission 22 is linked to a PTO shift lever 34 provided on the right side of the driver's seat 9 in the boarding driving unit 5 via a mechanical linkage mechanism for PTO shift. The power from the engine 2 is switched between two stages of high and low in conjunction with the operation of 34.

  As shown in FIGS. 3, 5, and 7, the ECU 25 controls the limiting means 25 </ b> C that limits the output rotational speed of the engine 2 so that the rotational speed of the PTO shaft 13 does not exceed the maximum rotational speed stored in advance. It is prepared as a program. Further, an output of a PTO shift sensor 35 for detecting a shift stage of the PTO transmission 22 is input from an operation position of the PTO shift lever 34.

  As shown in FIGS. 5 and 7, the limiting means 25 </ b> C performs limiting control for limiting the output rotational speed of the engine 2 based on the maximum rotational speed stored in advance and the output of the engine sensor 30. Specifically, in accordance with the connection command output from the PTO switch 32 in accordance with the operation of the PTO switch 32 to the “ON” position, the state is switched to an execution state in which the output rotation speed of the engine 2 is limited [# 1 in FIG. , # 4], the operation is switched to a stop state in which the output speed of the engine 2 is not limited based on the cutoff command output by the PTO switch 32 in accordance with the operation of the PTO switch 32 to the “OFF” position [# 2 in FIG. , # 5]. Further, when the PTO switch 32 is in the “automatic” position, the state is changed to the execution state based on the connection command output by the arm sensor 33 when the swing angle of the lift arm 12 is within the grounded angle region less than the set angle. When switching is performed (# 3, # 4 in FIG. 5), the lift arm 12 is switched to the stop state based on the shut-off command output by the arm sensor 33 when the swing angle of the lift arm 12 is within the angle range above the set angle. It changes [# 3, # 5 in FIG. 5]. In this execution state, the shift speed of the PTO transmission 22 is determined based on the output of the PTO shift sensor 35, and the engine 2 is determined from the speed ratio corresponding to the determined shift speed and the maximum rotation speed of the PTO shaft 13. The speed limit is calculated (# 6 in FIG. 5), and the calculated speed limit of the engine 2 is compared with the target speed (the larger set speed) of the engine 2 (# 7 in FIG. 5). When the speed limit of the engine 2 is lower than the target speed of the engine 2, the speed limit of the engine 2 is adopted as a new target speed and based on the new target speed and the output of the engine sensor 30. Thus, the accelerator restriction control for controlling the operation of the accelerator cylinder 24 is performed with priority over the accelerator control of the accelerator control means 25A so that the output speed of the engine 2 does not exceed the limit speed of the engine 2. And, the rotational speed of the PTO shaft 13 does not exceed the maximum rotational speed [# 8 in FIG. 5]. When the speed limit of the engine 2 is equal to or higher than the target speed of the engine 2 (the larger set speed), the accelerator control of the accelerator control means 25A is prioritized [# 9 in FIG. 5].

  As a result, the occurrence of inconveniences such as damage to the working device such as a rotary tiller operated by the power from the PTO shaft 13 due to overload caused by the rotation speed of the PTO shaft 13 exceeding the maximum rotation speed is prevented. can do. Further, it is possible to perform an accelerator operation with the accelerator lever 26 and the accelerator pedal 28 at a speed lower than the limit rotational speed.

  In this embodiment, the PTO switch 32 and the arm sensor 33 function as command means B for instructing switching of the PTO clutch 21 between switching and switching between the execution state and the stop state of the limiting means 25C.

  By the way, in the above configuration, for example, as shown in FIG. 8, the limit is based on the connection command (ON signal in FIG. 8) output by the PTO switch 32 when the PTO switch 32 is operated to the “ON” position. If the PTO clutch 21 is switched from the disconnected state to the connected state at the same time when the means 25C is switched from the stop state to the execution state, the output speed of the engine 2 is controlled by the control means of the limiting means 25C. The PTO clutch 21 is switched to the connected state until the rotational speed (the engine rotational speed corresponding to the maximum rotational speed of the PTO shaft 13) is lowered, and the rotational speed of the PTO shaft 13 may exceed the maximum rotational speed.

  Further, based on the disconnection command (OFF signal in FIG. 8) output by the PTO switch 32 when the PTO switch 32 is moved to the “disengaged” position, the PTO clutch 21 is simultaneously switched from the connected state to the disconnected state and restricted. When the means 25C is configured to switch from the execution state to the stop state, the PTO is set when the set rotational speed of the engine 2 set by the accelerator lever 26 or the accelerator pedal 28 greatly exceeds the above-described limit rotational speed of the engine 2. As the clutch 21 is switched to the disengaged state, the output rotation speed of the engine 2 may suddenly increase suddenly from the limit rotation speed of the engine 2 to the set rotation speed.

  Therefore, in this ECU 25, as shown in FIGS. 4 and 7, in accordance with the operation of the PTO switch 32 to the “ON” position, the connection command (ON signal in FIG. Is output based on this connection command, the PTO clutch control means 25B compares the engine speed limit of the engine 2 with the output of the engine sensor 30, and the engine sensor 30 outputs the output of the engine 2. The clutch valve 31 is operated so that the PTO clutch 21 remains in the disconnected state if the rotational speed is not less than the rotational speed limit of the engine 2 and the PTO clutch 21 is switched to the connected state if the rotational speed is less than the rotational speed limit of the engine 2. It is configured to control [# 4, # 5 in FIG. 4].

  Similarly, when the connection command for the PTO clutch 21 is output from the arm sensor 33 along with the downward swing of the lift arm 12 below the set angle with the PTO switch 32 positioned at the “automatic” position, Based on this connection command, the PTO clutch control means 25B compares the engine speed limit of the engine 2 with the output of the engine sensor 30, and the output speed of the engine 2 output by the engine sensor 30 is less than or equal to the engine speed limit of the engine 2. Otherwise, the PTO clutch 21 is maintained in the disconnected state, and if the output speed of the engine 2 output from the engine sensor 30 is equal to or lower than the limit speed of the engine 2, the clutch is set so that the PTO clutch 21 is switched to the connected state. It is comprised so that the action | operation of the valve 31 may be controlled [# 3-5 of FIG. 4].

  As a result, when the output of the engine sensor 30 exceeds the limit rotational speed of the engine 2 when the connection command for the PTO clutch 21 is output from the PTO switch 32 or the arm sensor 33, the execution is performed with the connection command at this time. Until the output of the engine sensor 30 is reduced to the limit rotational speed of the engine 2 by the control operation of the limiting means 25C switched to the state, the PTO clutch 21 is maintained in the disconnected state, and the output of the engine sensor 30 is Since the PTO clutch 21 is switched to the connected state as the limit rotational speed is reached, the working device that operates with the power from the PTO shaft 13 due to the rotational speed of the PTO shaft 13 exceeding the maximum rotational speed. The occurrence of inconvenience such as breakage due to overload can be prevented.

  If the output of the engine sensor 30 is equal to or lower than the speed limit of the engine 2 when the connection command for the PTO clutch 21 is output from the PTO switch 32 or the arm sensor 33, the limiting means 25C is determined by the connection command at this time. Is switched to the execution state and the PTO clutch 21 is switched to the connected state, so that the working device that is operated by the power from the PTO shaft 13 can be immediately operated.

  As shown in FIGS. 3, 6 and 7, the ECU 25 is used to switch from the execution state of the limiting means 25C to the stop state based on the PTO switch 32 or the PTO clutch 21 disconnection command from the arm sensor 33. A sudden increase prevention means 25D for preventing a sudden increase in the output rotational speed of the engine 2 is provided as a control program.

  The sudden rise prevention means 25D performs sudden rise prevention control based on switching from the execution state to the stop state of the restriction means 25C. Specifically, it is determined whether or not the restricting means 25C has switched from the execution state to the stop state based on the disconnection command of the PTO clutch 21 output from the PTO switch 32 or the arm sensor 33 [# 1 in FIG. When switching to the stop state, the speed of the PTO transmission 22 is determined based on the output of the PTO speed change sensor 35, and the engine is determined from the speed ratio corresponding to the determined speed and the maximum rotational speed of the PTO shaft 13. 2 is calculated (# 2 in FIG. 6), and the calculated limited rotation speed of the engine 2 is compared with the set rotation speed by the accelerator lever 26 and the accelerator pedal 28 (# 3 in FIG. 6). While either the set rotational speed by the lever 26 or the set rotational speed by the accelerator pedal 28 is larger than the limit rotational speed of the engine 2, the control is taken over by the limit control. Limit control is performed (# 4 in FIG. 6), and when both the set rotational speed by the accelerator lever 26 and the set rotational speed by the accelerator pedal 28 decrease below the limit rotational speed of the engine 2, the rapid increase prevention control is stopped and the accelerator is stopped. The control means 25A shifts to accelerator control [# 5 in FIG. 6].

  That is, if the limiting means 25C is switched to the execution state and the output rotational speed of the engine 2 is limited so that the rotational speed of the PTO shaft 13 does not exceed the maximum rotational speed, the accelerator lever 26 can be switched even if the limiting means 25C is switched to the stopped state. As long as the accelerator pedal 28 is operated to reduce the set rotational speed by the accelerator lever 26 and the accelerator pedal 28 to the target rotational speed of the engine 2 to the limited rotational speed of the engine 2 corresponding to the maximum rotational speed of the PTO shaft 13, the engine It becomes impossible to cancel the state of limiting the output rotational speed of 2.

  As a result, when the state of limiting the output rotational speed of the engine 2 is released, the accelerator control means 25A performs the accelerator control based on the target rotational speed of the engine 2 that has been reduced to the limited rotational speed of the engine 2. As a result, it is possible to reliably avoid the inconvenience that the output speed of the engine 2 suddenly increases and the vehicle body suddenly accelerates as the state of limiting the output speed of the engine 2 is released. And after canceling the state which restrict | limits the output rotation speed of the engine 2, the output rotation speed of the engine 2 can be changed into the arbitrary setting rotation speed set by operation of the accelerator lever 26 or the accelerator pedal 28. FIG.

    [Another embodiment]

[1] The work vehicle may be a riding rice transplanter, a riding mower, or a snow removal working vehicle. The working vehicle is not equipped with a PTO transmission 22, but is equipped with a PTO transmission 22 capable of shifting three or more stages, or a continuously variable PTO transmission 22, etc. Also good. Furthermore, the PTO shaft 13 may be provided in the front part or the front / rear intermediate part of the vehicle body.

[2] As the setting means A, either a lever type or a pedal type may be provided, or a dial type may be provided.

[3] The engine 2 is provided with a common rail type fuel injection device that electronically controls the fuel injection amount and injection timing, and the control means 25 detects the set rotational speed output by the setting means A and the detection means 30. Is controlled by controlling the operation of the supply pump for fuel pumping and a plurality of injectors for fuel injection based on the output rotational speed of the engine 2 output by You may comprise so that it may control.

[4] The control means 25 includes an accelerator lever based on the output of the lever sensor 27 for the accelerator lever, the output of the pedal sensor 29 for the accelerator pedal, and the output of the lever sensor that detects the operation position of the governing lever. The operation of the accelerator cylinder 24 may be controlled such that the operation position of the speed adjusting lever 23 corresponds to the operation position on the high speed side of the operation position of the accelerator 26 and the operation position of the accelerator pedal 28.

[5] The control means 25 is configured by connecting a main ECU for controlling the operation of the main transmission 16 and the PTO clutch 21 and the engine ECU for engine control so that they can communicate with each other by in-vehicle communication such as CAN communication. It may be a thing. Further, the limiting unit 25C may be configured to function as the sudden rise prevention unit 25D.

[6] As the limiting means 25C, the shift speed of the PTO transmission 22 is determined based on the output of the PTO shift sensor 35, and the PTO shaft is determined based on the speed ratio corresponding to the determined shift speed and the output of the engine sensor 30. 13 is calculated, and based on the calculated rotation speed of the PTO shaft 13 and the preset maximum rotation speed, the output rotation speed of the engine 2 is set so that the rotation speed of the PTO shaft 13 does not exceed the maximum rotation speed. It may be controlled. Further, the output rotational speed of the engine 2 is controlled based on the output of the rotation sensor for detecting the rotational speed of the PTO shaft 13 and the preset maximum rotational speed so that the rotational speed of the PTO shaft 13 does not exceed the maximum rotational speed. It may be a thing.

[7] As the PTO switch 32 that is also used as the command means B, a two-position switching type that commands the on / off of the PTO clutch 21 may be adopted. Further, instead of the PTO switch 32, a detection means for detecting the operation position of the PTO clutch lever, a detection means for detecting the on / off state of the PTO clutch 32, or the like may be used as the command means B. Further, a dedicated unit that commands only switching between the execution state and the stop state of the limiting unit 25C may be provided as the command unit B.

[8] As a reference form of the sudden rise prevention means 25D, the set rotational speed of the engine 2 set by the setting means A is larger than the limit rotational speed of the engine 2 (the engine rotational speed corresponding to the maximum rotational speed of the PTO shaft 13). In this case, as the limiting unit 25C is switched from the execution state to the stop state based on the output from the command unit B, the output rotation speed of the engine 2 gradually increases toward the set rotation speed at a preset increase rate. Thus, it is conceivable to control the output speed of the engine 2. Further, when the set rotational speed of the engine 2 set by the setting means A is larger than the limit rotational speed of the engine 2 (engine speed corresponding to the maximum rotational speed of the PTO shaft 13), it is based on the output from the command means B. The driver is notified of an increase in the engine speed in accordance with the switching of the limiting means 25C from the running state to the stopped state, and the output rotational speed of the engine 2 is preset after a predetermined time has elapsed since the switching of the limiting means 25C to the stopped state. It is conceivable to control the output rotational speed of the engine 2 so as to gradually increase toward the set rotational speed at the set rate of increase.

[9] When the rapid rise prevention means 25D is configured to continue the accelerator restriction control after the restriction means 25C is switched to the stopped state as in the above-described embodiment, the rapid rise prevention means 25D is switched to the stopped state. You may make it provide instruction | command means, such as a switch for exclusive use for (the accelerator restriction | limiting control by 25 C of rapid-rise prevention means is stopped). In this configuration, when the rapid rise prevention means 25D is switched to the stop state by the command means, the set rotational speed of the engine 2 set by the setting means A is equal to the limit rotational speed of the engine 2 (the maximum speed of the PTO shaft 13). If the engine speed is greater than the engine speed), the output speed of the engine 2 gradually increases toward the set speed at a preset rate of increase after the command means has switched to the stop state of the rapid increase prevention means 25D. You may comprise.

[10] As the control means 25, the difference between the set rotational speed of the engine 2 set by the setting means A and the rotational speed limit of the engine 2 (engine speed corresponding to the maximum rotational speed of the PTO shaft 13) is determined. The time required for the output rotational speed to decrease to the limit rotational speed may be obtained, and the PTO clutch 21 may be switched to the connected state after the obtained time has elapsed.

[11] The control means 25 includes an accelerator control means 25A, a limiting means 25C, and a sudden rise prevention means, and without preventing the rotational speed of the PTO shaft 13 from exceeding the maximum rotational speed when the PTO clutch 21 is connected. Further, it may be configured such that only a sudden increase in the output rotation speed of the engine 2 accompanying the switching from the execution state of the limiting means 25C based on the output from the command means B to the stop state is prevented.

[12] The control means 25 includes an accelerator control means 25A, a PTO clutch control means 25B, and a restriction means 25C, and the engine sensor 30 outputs when a command to connect the PTO clutch 21 is received from the command means B. When the output rotational speed of the engine 2 exceeds the limit rotational speed of the engine 2, the output of the engine sensor 30 is controlled by the control operation of the limiting means 25C switched to the execution state by the connection command at this time. The PTO clutch control means 25B keeps the PTO clutch 21 in the disengaged state until the number decreases, and the output speed of the engine 2 output by the engine sensor 30 decreases to the limit speed of the engine 2. By configuring the PTO clutch control means 25B to switch the PTO clutch 21 to the connected state, the PTO clutch Rotational speed of the PTO shaft 13 with one of the connection may be prevented from exceeding the maximum speed. The control means 25 in this configuration may be the one exemplified in the other embodiment of [10].

[13] An operation tool that enables the setting change of the maximum rotation speed of the PTO shaft 13 may be provided. Further, the maximum rotational speed of the PTO shaft 13 may be automatically changed according to the work device to be connected.

  The work vehicle control system according to the present invention can be applied to a work vehicle such as a tractor or a riding rice transplanter equipped with a work device that needs to limit the rotational speed of the PTO shaft.

2 Engine 13 PTO shaft 21 PTO clutch 25 Control means 25C Limiting means 25D Rapid rise prevention means 30 Detection means A Setting means B Command means

Claims (3)

The engine output speed is limited to control means for controlling the engine output speed so that the set speed set by the setting means can be obtained so that the PTO shaft speed does not exceed a preset maximum speed. A control system for a work vehicle configured to switch between an execution state for limiting the output speed of the engine and a stop state for not limiting based on an output from the command means.
When the control means switches from the execution state to the stop state in a state where the set speed exceeds the engine speed limit corresponding to the maximum speed, the switching is performed. A sudden rise prevention means for preventing a sudden rise in the output speed of the engine accompanying the
The sudden rise prevention means compares the set rotational speed with the limited rotational speed when the limiting means switches from the execution state to the stopped state, and the set rotational speed exceeds the limited rotational speed. And, unless the set rotational speed is changed to be equal to or lower than the limit rotational speed by the operation of the setting means, the engine output rotational speed is limited so that the engine rotational speed does not exceed the limit rotational speed, When the setting rotational speed is set to be less than or equal to the limit rotational speed by the operation of the setting means, the restriction on the output rotational speed of the engine is canceled and the set rotational speed exceeds the limit rotational speed. A work vehicle control system configured to allow the output rotational speed of the engine to exceed the limit rotational speed. A PTO clutch for intermittently transmitting power from the engine to the PTO shaft by the control operation of the control means;
The command means commands the PTO clutch to be engaged / disconnected, and the control means switches the PTO clutch to the connected state based on the PTO clutch connection command from the command means, and the restricting means switches to the execution state. also to claim 1, together with the control means on the basis of a disconnection instruction of the PTO clutch from said command means switches the PTO clutch disconnected state is the limiting means are configured to switch to the stop state The work vehicle control system described. A detecting means for detecting the output rotational speed of the engine;
The control means compares the output of the detection means with the limit rotational speed based on the PTO clutch connection command from the command means, and if the output of the detection means exceeds the limit rotational speed, 3. The work vehicle control system according to claim 2 , wherein the PTO clutch is maintained in a disengaged state, and the PTO clutch is switched to an engaged state when the output of the detecting means is equal to or lower than the limit rotational speed. .

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