JP2012056542A - Wheel type working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel type working vehicle capable of simplifying constitution of the vehicle, improving assembling property and maintainability and reducing an engine load, by using an electric motor as the driving source of the front wheel.SOLUTION: The wheel type working vehicle has right and left front wheels 23 and rear wheels 24 on front and rear parts of the vehicle, wherein the motive power of an engine 40 disposed on a vehicle body frame 22 is transmitted to the rear wheel 24 via a transmission case 42, and at the same time, the front wheels 23 are operated with a steering operation to turn the vehicle. The electric motor 5 driven by electric power of a battery 4 is disposed on a position in the neighborhood of the front wheel 23 and, at the same time, the electric motor 5 is connected to a controller C via an inverter I, controls the drive of the electric motor 5 with the controller C on the basis of the running load state of the rear wheel 24 and the turning state of the vehicle, and the front wheel 23 is driven by the electric motor 5.

Description

  The present invention relates to a wheel-type work vehicle that includes left and right front wheels and rear wheels on the front and rear sides of a vehicle, and transmits the power of an engine installed on a vehicle body frame to a rear wheel via a transmission. An electric motor that is driven by battery power is installed in the vicinity, and this electric motor is connected to the controller via an inverter, and the electric motor is driven by the controller based on the running state of the rear wheels and the turning state of the vehicle. The present invention relates to a wheel-type work vehicle that controls the front wheels and drives the front wheels with an electric motor.

  Some conventional wheeled tractors are equipped with a four-wheel drive / front-wheel acceleration mechanism on the front-wheel drive output shaft. When the traction force is increased or the rear wheel slips in a field, etc., the four-wheel drive / front-wheel In some cases, the front wheels are driven by a speed increasing mechanism and the vehicle is driven to four wheels, so that load distribution of each wheel becomes appropriate and driving stability is improved.

JP 2006-10533 A

However, in such a conventional wheel-type tractor, the front power of the front part of the vehicle from the auxiliary transmission is used as a path for transmitting power to the front wheels separately from the path for transmitting engine power to the rear wheels via the main auxiliary transmission. Because it requires a front wheel drive transmission shaft toward the axle, it requires additional mechanical members such as gears and drive shafts, and requires installation space for them. There was a problem that the maintainability was poor, the cost was high, and the configuration could not be simplified. In addition, since it is necessary to provide the front wheel drive transmission shaft with a four-wheel drive / front wheel speed increasing mechanism used for turning on and off the front wheel drive, there is also a problem that the manufacturing cost and the maintainability are poor.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wheeled work vehicle that uses an electric motor as a drive source for the front wheels, thereby simplifying the vehicle configuration, improving assemblability and maintainability, and reducing engine load. It is to provide.

  For this reason, the invention according to claim 1 is provided with left and right front wheels and rear wheels on the front and rear sides of the vehicle, and transmits the power of the engine installed on the vehicle body frame to the rear wheels via a transmission case, as well as steering operation. In a wheeled work vehicle that steers the front wheel to turn the vehicle, an electric motor that is driven by battery power is installed near the front wheel, and the electric motor is connected to the controller via an inverter. And the controller controls the drive of the electric motor based on the running load state of the rear wheel and the turning state of the vehicle, and the front wheel is driven by the electric motor.

  According to a second aspect of the present invention, in the wheeled work vehicle according to the first aspect, the electric motor is installed on a front surface, a rear surface, or an upper surface of a center portion of a front axle case to which the front wheel is attached. .

  According to a third aspect of the present invention, in the wheeled work vehicle according to the first aspect, the electric motor has the motor shaft connected to a ring gear of a differential device provided in the front axle case. Features.

  According to a fourth aspect of the present invention, in the wheeled work vehicle according to the first aspect, the battery is installed in each of a plurality of battery cases attached to the body frame via a support member. .

  According to a fifth aspect of the present invention, in the wheeled work vehicle according to the first aspect, the battery is in the vicinity of a lifting step for assisting the lifting and lowering of the vehicle, and below the control unit that controls the vehicle. It is characterized by being arranged.

  According to a sixth aspect of the present invention, in the wheeled work vehicle according to the first aspect, a slip detector that detects a slip state of the rear wheel is installed in the vehicle, and the slip detector is connected to the controller. And the controller controls driving of the electric motor based on detection information of the slip detector.

  According to a seventh aspect of the present invention, in the wheeled work vehicle according to the first and sixth aspects, the slip detector includes a rotational speed detector that detects the rotational speed of the rear wheel, and an actual speed of the vehicle. A vehicle speed detector to detect and a distance detector to detect the moving speed of the vehicle, and from the actual speed of the vehicle by detection of the vehicle speed detector and the travel distance of the vehicle by detection of the distance detector, The ratio of the actual rotational speed to the rotational speed of the rear wheel is calculated, and the slip state of the rear wheel is determined based on the calculated value.

  According to an eighth aspect of the present invention, in the wheeled work vehicle according to the first aspect, a torque detector that detects a load torque applied to the rear wheel is installed on the drive shaft of the rear wheel, and the torque A detector is connected to the controller, and the controller controls the drive of the electric motor based on detection information of the torque detector.

  According to a ninth aspect of the present invention, in the wheeled work vehicle according to the first aspect, the steering is provided with an angle detector that detects a steering angle of the steering, and the angle detector is provided in the controller. Based on the detection information of the angle detector, the controller controls the drive of the electric motor by the vehicle at a predetermined vehicle speed or less.

  According to a tenth aspect of the present invention, in the wheeled work vehicle according to the first aspect, the electric motor is separately attached to both ends of the front axle case, and the motor shaft of the electric motor is disposed in front of the front wheel. It is characterized by being an axle.

  According to the first aspect of the present invention, the front and rear front and rear wheels are provided on the front and rear sides of the vehicle, and the power of the engine installed on the vehicle body frame is transmitted to the rear wheels via the transmission case, and by steering operation. In a wheeled work vehicle that steers the front wheel and turns the vehicle, an electric motor driven by battery power is installed near the front wheel, and the electric motor is connected to the controller via an inverter, The drive of the electric motor is controlled by the controller based on the running load state of the rear wheels and the turning state of the vehicle, and the front wheels are driven by the electric motor, so power was transmitted from the transmission case to the front axle as in the past. Eliminates the need for a front-wheel drive output shaft and four-wheel drive / front-wheel speed-increasing mechanism. Can turn on and off the driving of the wheels, it is possible to simplify the vehicle configuration. Therefore, it is possible to provide a wheeled tractor with improved assemblability and maintainability.

  According to the second aspect of the present invention, since the electric motor is installed on the front surface, the rear surface, or the upper surface of the center portion of the front axle case to which the front wheels are attached, the installation space is effectively used, and the differential in the front axle case is used. An electric motor can be stably installed in the vicinity of the apparatus. Therefore, it is possible to provide a wheeled tractor that saves space in the vehicle.

  According to the third aspect of the present invention, since the motor shaft is connected to the ring gear of the differential device provided in the front axle case, the electric motor can be greatly used to connect the electric motor to the front wheel drive unit. The electric motor can be easily connected to the existing differential without changing the design and structure. Therefore, a wheeled tractor with improved productivity can be provided.

  According to the fourth aspect of the present invention, since the battery is installed in each of the plurality of battery cases attached to the vehicle body frame via the support member, the heavy battery needs to have a separate high-strength attachment member. Therefore, it can be stably installed on an existing body frame having high strength. Therefore, it is possible to provide a wheeled tractor with excellent productivity.

  According to the fifth aspect of the present invention, the battery is disposed in the vicinity of the ascending / descending step for assisting the ascending / descending to the vehicle and below the control unit for maneuvering the vehicle. The vehicle can be stabilized by making the weight balance of the vehicle good. Therefore, it is possible to provide a wheeled tractor that achieves a compact vehicle.

  According to the invention of claim 6, the vehicle is provided with a slip detector that detects the slip state of the rear wheel, and the slip detector is connected to the controller, and based on the detection information of the slip detector, Since the controller controls the drive of the electric motor, the front wheels are automatically driven by the electric motor when necessary, such as when the rear wheels slip and it is difficult to run, and the vehicle is put into a four-wheel drive state. It can assist driving. Therefore, it is possible to provide a wheeled tractor having excellent usability.

  According to the seventh aspect of the present invention, the slip detector includes a rotational speed detector that detects the rotational speed of the rear wheel, a vehicle speed detector that detects the actual speed of the vehicle, and a distance that detects the moving speed of the vehicle. The ratio of the actual rotational speed to the normal rear wheel speed is calculated from the actual vehicle speed detected by the vehicle speed detector and the vehicle travel distance detected by the distance detector. Therefore, the slip condition of the rear wheel can be detected with a simple configuration. Therefore, a wheeled tractor with improved productivity can be provided.

  According to the eighth aspect of the present invention, a torque detector for detecting the load torque applied to the rear wheel is installed on the drive shaft of the rear wheel, and the torque detector is connected to the controller. Since the controller controls the electric motor based on the detected information, the front wheel is automatically moved by the electric motor when necessary, such as when the rear wheel gets stuck in mud such as a paddy field and the traction force of the vehicle pulling the rear work equipment decreases. Driving the vehicle to bring the vehicle into a four-wheel drive state can enhance the traction force of the vehicle. Therefore, it is possible to provide a wheeled tractor having excellent usability.

  According to the ninth aspect of the present invention, the steering is provided with an angle detector for detecting the steering angle of the steering, the angle detector is connected to the controller, and the controller is based on the detection information of the angle detector. Since the vehicle controls the drive of the electric motor below the predetermined vehicle speed, the vehicle is automatically switched to the front-wheel accelerated drive state in which the peripheral speed of the front wheels is increased more than the peripheral speed of the rear wheels when the vehicle turns. The vehicle can quickly turn without roughening the surface. A wheeled tractor excellent in usability can be provided.

  According to the invention described in claim 10, since the electric motor is separately attached to both ends of the front axle case, and the motor shaft of the electric motor is used as the front axle of the front wheel, the left and right front wheels are separately provided by the electric motor. Thus, it is possible to transmit the driving force to the front wheels with a simple configuration without the need for a differential device, a left and right front wheel transmission shaft, a king pin, etc., which are built in the front axle case as in the prior art. Therefore, it is possible to provide a wheeled tractor that is excellent in assemblability and maintainability.

It is a side view of the wheel type tractor as an example of the present invention. It is a skeleton figure of a power transmission system. It is a perspective view of the front axle case attached to the vehicle body frame. It is a perspective view of the body frame which shows the example of attachment of a battery. It is a top view of the wheel type tractor which shows the installation position of a battery. It is a top view of the front axle case which shows the installation position of an electric motor. It is a structural diagram of the front axle showing the installation of the electric motor. It is an assembly drawing of the front-wheel differential mechanism and the left front-wheel drive shaft which show linkage of an electric motor. It is a top view of the front axle case which shows another installation position of an electric motor. It is a control block diagram of the front wheel drive by a controller. It is a perspective view of a steering mechanism. It is a rear view of one end part of a front axle case showing the electric motor attached to the inner side of the front wheel. FIG. 4 is a control block diagram of a controller that performs front wheel drive with left and right electric motors.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a side view of a wheeled tractor as an example of the present invention. The tractor 1 of this example includes a front wheel 23 and a rear wheel 24 before and after a vehicle body frame 22, a bonnet 25 is formed above the front wheel 23, and an engine 40 as a prime mover portion and a clutch at a rear portion of the engine 40 inside A housing 41 is disposed, and a transmission case 42 is disposed at a rear portion of the clutch housing 41, and power from the engine 40 is transmitted to the rear wheel 24. And the control part 27 is provided in the rear part of the bonnet 25 continuously.

  In the control unit 27, an operation pedal such as a clutch pedal 28, a steering handle 29, a driver seat 30, and the like are provided as a vehicle operation unit. Further, an elevating step 37 for the driver to get on and off the control unit 27 may be fixedly attached to the vehicle body frame 22 below the control unit 27.

  The power from the engine 40 is transmitted to a PTO shaft (not shown) protruding from the rear end of the transmission case 42, and the PTO shaft is connected to the rear end of the vehicle via a universal joint or work implement mounting device (not shown). The illustrated rear working machine is driven.

  Next, the configuration of power transmission will be described. FIG. 2 shows a skeleton diagram of the power transmission system. A multi-plate main clutch 43 is accommodated in the clutch housing 41 and linked to the clutch pedal 28. The rotation of the output shaft 44 of the engine 40 is input to the main clutch 43, and the output shaft 45 of the main clutch 43 extends rearward of the vehicle and is provided at the same axis as the PTO clutch shaft 46.

  A transmission gear 47 is disposed at the rear end of the output shaft 45, and a PTO first speed gear 48, a PTO second speed gear 49, and a PTO reverse gear 50 are loosely fitted on the PTO clutch shaft 46. The PTO first speed gear 48, the PTO second speed gear 49, and the transmission gear 47 are engaged with transmission gears 52, 53, and 54 provided on the main shaft 51, respectively, and the PTO reverse gear 50 is a counter gear 55. , The rotational driving force is transmitted from the transmission gears 52, 53, 56 to the PTO shaft 60 via the PTO clutch shaft 46 and the reduction gear 59 by sliding of the PTO clutch sliders 57, 58. Drive the work equipment.

  Transmission gears 52, 53, 54, 56 fixed to the main shaft 51 are loosely fitted to the main transmission shaft 61, a main transmission first speed gear 62, a main transmission second speed gear 63, a main transmission third speed gear 64, The gears are respectively meshed with the transmission fourth gear 65. Two main transmission clutch sliders 66 and 67 that are spline-fitted so as to be slidable in the axial direction of the main transmission shaft 61 are linked to a main transmission lever (not shown) provided in the cabin 27. By operating the main transmission lever, the main transmission clutch sliders 66 and 67, the main transmission first speed gear 62, the main transmission second speed gear 63, the main transmission third speed gear 64, and the main transmission fourth speed gear 65 are selected. Power is transmitted from the main shaft 51 to the main transmission shaft 61 via the one main transmission gear 62, 63, 64, 65.

  Further, a forward rotation side gear 68 and a reverse rotation side gear 69 are loosely fitted on the same shaft center in a forward extension portion of the main transmission shaft 61 in the vehicle traveling direction. Then, by operating a reverser lever (not shown) provided in the cabin 27, the reverser clutch 70 is selectively connected to either the forward side or the reverse side, and the rotation of the main transmission shaft 61 is rotated in the forward rotation side gear 68 or the reverse rotation side gear 69. Communicated to either. However, when the reverser lever is in the neutral position, the rotation is not transmitted to either the forward rotation side gear 68 or the reverse rotation side gear 69.

  The forward rotation side gear 68 is engaged with a gear 72 fitted to the transmission shaft 71, and the reverse rotation side gear 69 is engaged with a counter gear 74 fitted to the counter shaft 73, and the counter gear 74 is engaged with the transmission shaft 71. The gear 75 is engaged with the gear 75.

  As a result, when the reverser clutch 70 is connected to the forward side, the rotational power of the main transmission shaft 61 is transmitted to the transmission shaft 71 via the forward rotation side gear 68, and the reverser clutch 70 is connected to the reverse side. The rotational power of the main transmission shaft 61 allows the transmission shaft 71 to rotate in the reverse rotation direction from the reverse rotation side gear 69 via the counter shaft 73.

  A gear 72 fitted to the transmission shaft 71 meshes with the forward rotation side gear 68 and meshes with a gear 77 provided on the coaxial line of the auxiliary transmission shaft 76 and in front of the vehicle traveling direction. A sub transmission shifter 78 is spline-fitted to the sub transmission shaft 76 so that it can freely slide between the front portion of the sub transmission shaft 76 and the rear portion of the gear 77.

  The auxiliary transmission shifter 78 is operated by an auxiliary transmission lever (not shown) provided in the cabin 27, and the auxiliary transmission third speed in a state where the auxiliary transmission shifter teeth formed at the front part of the auxiliary transmission shifter 78 are located at the rear part of the gear 77. (Secondary transmission high speed stage), the second transmission second gear in a state where the second gear shifter teeth mesh with the teeth provided at the rear end of the gear 77, the teeth formed at the upper center of the second transmission shifter 78 and the transmission shaft 71. A sub-speed first speed in a state in which the gear 79 provided in the vicinity of the center is engaged, a state in which rotational power is not transmitted to the sub-shift shifter 78 (neutral), and teeth on the rear portion of the sub-shift shifter 78 and a super low speed gear (not shown) The sub-transmission device is configured to be switchable to the sub-transmission ultra-low speed (C speed) in a state where the gears mesh with each other.

  By selecting the gear meshing by sliding of the auxiliary transmission shifter 78, the rotation of the transmission shaft 71 is output through three speeds, and the rotational power input to the auxiliary transmission shaft 76 is provided to the auxiliary transmission shaft 76. It is output to the rear wheel drive system by three gears 80, 81, 82 and the like.

  A rear wheel differential device 83 is disposed behind the transmission case 42, and rotation of the auxiliary transmission shaft 76 is input to the rear wheel differential device 83 via a gear 82 formed at the rear end of the auxiliary transmission shaft 76. The rear wheel 24 is driven via an axle in the rear axle case. Reference numeral 84 denotes a brake device.

  On the other hand, in the front axle case 2, as shown in FIG. 2 and FIGS. 7 to 8 which will be described later, a differential device 7 is installed at the center, and a pair of front wheels are laterally extended from the differential device 7. A transmission shaft 8 is extended, and the left and right front wheel transmission shafts 8 are connected to a final gear 10 and the like via king pins 9, respectively. The final gear 10 is connected to the front axle 23a of the front wheel 23, and the front wheel 23 is attached to the front end of the front axle 23a.

  The differential 7 includes a hollow differential case 7a supported in the front axle case 2, a ring gear 7b fixed to one outer peripheral surface of the differential case 7a, and a pinion shaft that rotates integrally with the differential case 7a. 7c, a pinion 7d that is rotatably arranged at both ends of the pinion shaft 7c, and a differential side gear 7e that meshes with the pinion 7d and rotates the left and right front wheel transmission shaft 8.

  That is, the rotation of the ring gear 7b causes the left and right front wheel transmission shafts 8 to rotate via the differential device 7, and the rotation of the front axle 23a causes the front wheels 23 to rotate via the king pins 9, the final gear 10, and the like. Since the differential device 7 is a well-known technique, a detailed description thereof is omitted.

  Therefore, the vehicle is normally capable of working with two-wheel drive of the rear wheel 24. However, as will be described later, the rear wheel 24 is in a slipping state. When driving and making load distribution appropriate for each wheel to improve running stability, the ring gear 7b is rotated by an electric motor 5 described later in detail, and the differential gear 7 is used as described above. The left and right front wheel transmission shaft 8 rotates, and further, there is a four-wheel drive mechanism that rotates the front wheel 23 by the rotation of the front axle 23a via the king pin 9, the final gear 10, or the like. Further, when the vehicle in a two-wheel drive or four-wheel drive state is turned, the vehicle has a front wheel speed increasing mechanism that increases the rotational speed of the electric motor 5 to substantially double the peripheral speed of the front wheel 23.

  In this way, by changing the vehicle from two-wheel drive to timely four-wheel drive, the engine load is reduced (improves fuel consumption and exhaust gas is reduced), and operability is improved by using two-wheel drive that has a lighter steering force than four-wheel drive. It is to make.

  Next, a specific configuration of the front wheel drive system of the present invention will be described. 3 is a perspective view of a front axle case attached to the vehicle body frame, FIG. 4 is a perspective view of the vehicle body frame showing an example of battery attachment, FIG. 5 is a plan view of a wheeled tractor showing a battery installation position, and FIG. 7 is a plan view of the front axle case showing the installation position of the motor, FIG. 7 is a structural diagram of the front axle showing the installation of the electric motor, FIG. 8 is an assembly diagram of the front wheel differential mechanism and the left front wheel drive shaft showing the linkage of the electric motor, FIG. 9 is a plan view of a front axle case showing another installation position of the electric motor, and FIG. 10 is a control block diagram of front wheel drive by the controller.

  First, as shown in FIG. 3, a front axle case 2 is provided at the lower part of a vehicle body frame 22 at the front portion of the vehicle on which the engine 40 and the like are mounted, in which two frames 22a and 22b are arranged in parallel in the vehicle longitudinal direction. A front wheel 23 shown in FIG. 1 is attached to both left and right ends of the front axle case 2.

  For example, as shown in FIG. 4, the vehicle body frame 22 has a rectangular shape that is a rear portion of the vehicle body frame 22 and has a top surface opened between the vehicle outer surface of the frames 22 a and 22 b and the frames 22 a and 22 b. Metal battery cases 3 are installed. These battery cases 3 are juxtaposed in such a manner that the upper surfaces of the left and right side portions are bridged to the upper surface of the rear portion of the vehicle body frame 22 by welding or bolt fastening in the vehicle left-right direction. The two stays s are fixed with bolts or the like.

  In these battery cases 3, a battery 4 such as a lithium ion battery is fixedly installed by a fixing member (not shown) as appropriate. These batteries 4 may be removed from the front surface or the rear surface of the battery case 3, and the number of the battery cases 3 and the batteries 4 is not limited to three as described above. The battery 4 is connected to a controller C described later for voltage control.

  Further, as the installation positions of these batteries 4, preferably, as shown in FIG. 5, a frame 22a extending from the frames 22a and 22b in the vicinity of the elevating step 37 and below the control unit 27 toward the rear of the vehicle. Optimize the weight balance of the vehicle and effectively utilize the space of the vehicle by fixing and installing in the battery case 3 installed in the same manner as described above between ', 22b' and on the outer surface of the frames 22a ', 22b' Can do. The battery 4 is not limited to the vicinity of the lifting step 37 described above, but is not shown, but may be erected between the left and right fenders behind the driver's seat 30 and on the vehicle body frame 22 with appropriate stays or fasteners. Good.

  Next, as shown in FIG. 6, for example, a cylindrical electric motor 5 is attached to the front rear case case 2 at the center rear surface thereof. At this time, the motor shaft 5a of the electric motor 5 is attached to the front of the vehicle. It is inserted into the front axle case 2 and attached. The electric motor 5 is fixed to the center rear surface of the front axle case 2 by bolting or the like via a spacer 6 or the like.

  And in the wheel-type tractor 1 of a present Example, the electric motor 5 is connected to the ring gear 7b mentioned above. A hole h for connecting the front wheel drive transmission shaft extending forward from the transmission case 42 to the ring gear 7b is formed on the rear surface of the center portion of the conventional front axle case 2 where the differential 7 is located. Forming.

  Therefore, in this example, the hole h is used to attach the electric motor 5 to the central rear surface of the front axle case 2 as described above, and the motor shaft 5a is connected to the ring gear 7b via the hole h. It is preferable to connect them. At this time, the bevel gear 5b is attached to the tip of the motor shaft 5a, and the bevel gear 5b is engaged with the ring gear 7b.

  The installation position of the electric motor 5 on the front axle case 2 is not limited to the central rear surface of the front axle case 2 described above, and as shown in FIG. It may be attached. In this case, the motor shaft 5a of the electric motor 5 is directed toward the rear of the vehicle and inserted from a hole (not shown) formed in the center front surface of the front axle case 2, and the bevel gear 5b at the tip of the motor shaft 5a is engaged with the ring gear 7b. .

  Or you may install the electric motor 5 in the center upper surface of the front axle case 2, as shown to the dotted line of FIG. In this case, although not shown, the motor shaft 5a is connected to the ring gear 7b through a hole formed in the upper surface of the front axle case 2.

  The motor shaft 5a of the electric motor 5 is provided with an electromagnetic clutch 5c in the middle thereof, and the rotational drive of the motor shaft 5a is transmitted to the ring gear 7b or not transmitted by turning on and off the clutch 5c. Can be in a state.

  With such a configuration, a mechanical member such as a front wheel drive transmission shaft or a mechanical member such as a drive shaft is not required from the auxiliary transmission shaft 76 in the transmission case 42 to the front axle case 2 as in the conventional configuration. In addition to simplification, the battery 4 can be efficiently installed in the installation space and the battery 4 can be efficiently installed.

  Next, the slip detector 11 that detects the slip state of the rear wheel 24 is installed in the vehicle. For example, as shown in FIG. 2, the slip detector 11 is a hollow cylindrical shaft-shaped rotary encoder or the like installed on the rear axle of the left and right rear wheels 24 in order to detect the number of rotations of the rear wheels 24 ( (Not limited to) known rotational speed detectors 11aa and 11ab, and a known actual speed detector 11b including, for example, an ultrasonic transducer for detecting the actual speed of the vehicle installed at an appropriate position of the vehicle; For example, a well-known distance detector 11c including a light source and a light-receiving / emitting lens for detecting the travel distance of the vehicle is installed at an appropriate position of the vehicle.

  Since the actual speed detector 11b is a well-known technique, a detailed description thereof is omitted. However, the actual speed detector 11b detects the speed of the vehicle to the ground by transmitting and receiving ultrasonic waves to the road surface. For example, the actual speed of the vehicle may be calculated from the rotational speed of the front wheel 23 based on detection information such as a rotary encoder provided on the front axle of the front wheel 23.

  Furthermore, known torque detectors 12 a and 12 b having a hollow cylindrical shaft shape for detecting a load torque applied to the rear wheels 24 are installed on the rear axles of the left and right rear wheels 24. Therefore, for example, one end of the torque detector 12a (12b) is fixed with a bolt to a hub (not shown) at the tip of the rear axle of each rear wheel 24, and the other end of the torque detector 12a (12b) is The rotation speed detectors 11aa and 11ab can be coaxially fixed to the wheel with bolts and at the wheel side center.

  As shown in FIG. 10, the rotation speed detectors 11aa and 11ab and the torque detectors 12a and 12b are connected to a controller C installed at an appropriate position of the vehicle, and the electric motor 5 is connected to an inverter. Connected through I. A clutch 5 c provided on the motor shaft 5 a of the electric motor 5 is also connected to the controller C.

  Here, first, when one or both of the left and right rear wheels 24 starts to slip in a field in which a vehicle that is being driven by rear wheel drive in a farm field or the like is in a field condition, the controller C detects the rotation speed detector of the slip detector 11. 11aa, 11ab, the actual speed detector 11b, and the detection information sent from the distance detector 11c, the actual number of revolutions relative to the number of revolutions of the normal rear wheel 24 according to the actual speed of the vehicle and the travel distance (constant section). The ratio is calculated, and it is determined that the rear wheel 24 is in the slip state based on the calculated value.

  Next, the controller C rotates the electric motor 5 through the inverter I at a predetermined rotational speed corresponding to the vehicle speed, for example. When the controller C operates the clutch 5c and connects the clutch 5c, the rotation of the motor shaft 5a is transmitted to the ring gear 7b, and from the differential device 7 via the left and right front wheel transmission shafts 8 as described above. By setting the four-wheel drive state in which the front wheels 23 are driven, it is possible to assist vehicle travel in the field.

  At this time, after the electric motor 5 is driven, the clutch 5c is connected to transmit the driving force of the electric motor 5 to the ring gear 7b and the front wheel 23 is driven. Can be started.

  Further, the rear wheel 24 is released from the slip state, and the controller C performs the rear operation based on the calculated values calculated from the detection information sent from the rotation speed detectors 11aa and 11ab, the actual speed detector 11b, and the distance detector 11c. When it is determined that the wheel 24 is in a normal driving state, the drive of the electric motor 5 is stopped via the inverter I, and the clutch 5c is disconnected to return the vehicle to the rear wheel driving state, and the front wheel 23 is driven. State.

  With such a configuration, when the rear wheel 24 of the vehicle slips and it is difficult to travel, the front wheel 23 is automatically driven by the electric motor 5 when necessary, and the vehicle is brought into a four-wheel drive state. It can assist driving.

  Next, when a rear-wheel drive vehicle enters a wetland or the like and performs a towing operation of a rear work machine or the like, when the wheel 24 tends to fit in the wetland, the traction force is insufficient and the work efficiency is reduced, the controller C When the torque value applied to the left and right rear wheels 24 is greater than a predetermined value based on torque detection information sent from the torque detectors 12a and 12b installed on the rear wheels 24, the rear wheels 24 are insufficient in traction force. Judge that.

  Next, the controller C rotates the electric motor 5 through the inverter I at a predetermined rotational speed corresponding to the vehicle speed, for example. When the controller C operates the clutch 5c and connects the clutch 5c, the rotation of the motor shaft 5a is transmitted to the ring gear 7b, and from the differential device 7 via the left and right front wheel transmission shafts 8 as described above. By setting the four-wheel drive state in which the front wheels 23 are driven, it is possible to increase the traction force of the rear working machine in the wet field. As described above, after the electric motor 5 is in the driving state, the clutch 5c is connected to transmit the driving force of the electric motor 5 to the ring gear 7b and the front wheel 23 is driven. It can be started well.

  Further, when the vehicle leaves the wet field and stops the towing work of the rear working machine or tows the towing work in the field under other conditions, the controller C is sent from the torque detectors 12a and 12b of the rear wheel 24. From the detected torque information, when the torque value applied to the left and right rear wheels 24 falls below a predetermined value, it is determined that a large traction force is not required, and the electric motor 5 is driven via the inverter I. By stopping and disconnecting the clutch 5c, the vehicle is returned to the rear wheel drive state, and the front wheel 23 is set to the driven state.

  With such a configuration, the front wheel 23 is automatically driven by the electric motor 5 when necessary, such as when the rear wheel 24 of the vehicle gets stuck in mud such as a paddy field and the traction force of the vehicle pulling the rear work machine decreases. By setting the to the four-wheel drive state, the traction force of the vehicle can be increased.

  Although the electric motor 5 having the clutch 5c on the motor shaft 5a has been described above, the motor shaft 5a may be directly connected to the ring gear 7b without providing the clutch 5c. As described above, since the front wheels 23 are driven by the electric motor 5 as necessary, the front wheels 23 are in a driven state in a normal rear wheel driving state.

  That is, the motor shaft 5a connected to the ring gear 7b is driven from the ring gear 7b of the differential device 7 through the final gear 10, the king pin 9, the left and right front wheel transmission shafts 8 and the like by the driven rotation of the front wheels 23. Since 5a is always driven and rotated, the electric motor 5 can generate power. Therefore, when the electric power obtained from the electric motor 5 is stored in the battery, the energy can be used effectively.

  In the wheel type tractor 1 of the present invention, the front wheels can be driven at an increased speed using the electric motor 5 described above when the vehicle turns. FIG. 11 is a perspective view of the steering mechanism.

  As shown in FIG. 11, the front wheel 23 is steered by, for example, rotating a steering shaft 29a to the left and right by a steering handle 29 to switch a steering valve (not shown), and extending and contracting a hydraulic cylinder 29b to move a piston rod 29c and a tie rod 29d. This is a well-known technique for turning the left and right front wheels 23 via the wheel.

  A known angle detector 13 such as a potentiometer is installed on the steering shaft 29a of the steering handle 29, for example. As shown in FIG. 10, the angle detector 13 is connected to the controller C, and the controller 5 is connected to the electric motor 5 via the inverter I as described above. A clutch 5 c provided on the motor shaft 5 a of the electric motor 5 is also connected to the controller C.

  Here, when the operator steers the steering handle 29 to steer the front wheel 23 and turns the vehicle, the controller C determines that the vehicle speed is low (for example, sub-shift is 1 based on detection information from the actual speed detector 11b, for example). In addition to traveling at the second speed), from the detection information of the steering angle of the steering wheel 29 sent from the angle detector 13 installed on the steering shaft 29a, the steering angle is not less than a predetermined steering angle. It is determined that the vehicle is turning. In addition to the above, the controller C determines that the vehicle is in a turning state even when the vehicle uses a steering brake.

  Next, the controller C turns the electric motor 5 through the inverter I to a predetermined rotational speed corresponding to the vehicle speed and the steering angle of the front wheels 23 (for example, the peripheral speed of the front wheels 23 is approximately 2 with respect to the peripheral speed of the rear wheels 24). Rotation speed of the electric motor 5 that gives a double driving force to the front wheels 23).

  When the controller C operates the clutch 5c and connects the clutch 5c, the rotation of the motor shaft 5a is transmitted to the ring gear 7b, and from the differential device 7 via the left and right front wheel transmission shafts 8 as described above. By setting the four-wheel drive state in which the front wheels 23 are driven, the vehicle can be quickly turned without roughening the work surface. As described above, after the electric motor 5 is in the driving state, the clutch 5c is connected to transmit the driving force of the electric motor 5 to the ring gear 7b and the front wheel 23 is driven. Can be started automatically.

  When the vehicle finishes turning and returns to a straight traveling state, the controller C determines that the steering handle 29 is a predetermined value from the detection information of the steering angle of the steering handle 29 sent from the angle detector 13 of the steering shaft 29a. When the steering angle is less than or equal to the steering angle, it is determined that the vehicle is traveling straight, the drive of the electric motor 5 is stopped via the inverter I, and the clutch 5c is disconnected to return the vehicle to the rear wheel driving state. The front wheel 23 is set to the driven state.

  With such a configuration, when the vehicle turns, the vehicle is automatically switched to the front wheel acceleration driving state in which the circumferential speed of the front wheel 23 is increased more than the circumferential speed of the rear wheel 24, and the vehicle can be quickly moved without roughening the work surface. Can be swiveled.

  Further, by using the electric motor 5 as the speed increasing drive source of the front wheel 23, the front wheel drive transmission shaft provided from the auxiliary transmission shaft 76 in the transmission case 42 toward the front axle case 2 as in the prior art, Since it is not necessary to install a four-wheel drive / front wheel speed increasing mechanism and the electric motor 5 can be configured simply, the assemblability and maintenance are significantly improved.

  The front wheel drive by the electric motor 5 described above can also be configured to be performed manually. In this case, as shown in FIG. 10, for example, the front wheel drive on / off switch 14 installed near the driver's seat 30 is connected to the controller C.

  Furthermore, the electric motor 5 is connected to the controller C through the inverter I as described above, and the clutch 5c provided on the motor shaft 5a of the electric motor 5 is also connected to the controller C.

  With such a configuration, in addition to the drive control by the electric motor 5 of the front wheel 23 using the slip detector 11 and the drive control by the electric motor 5 of the front wheel 23 using the torque detectors 12a and 12b, work can be performed as necessary. When the person turns on / off the front wheel drive on / off switch 14, the controller C can turn on / off the drive of the electric motor 5 and drive or follow the front wheel 23.

  Moreover, the installation of the electric motor 5 is not limited to the above-described position and installation method. FIG. 12 is a rear view of one end portion of the front axle case showing the electric motor attached to the inner side of the front wheel, and FIG. 13 is a control block diagram of a controller that drives the front wheels with the left and right electric motors.

  In this case, as shown in FIG. 12, for example, the outer rotor type electric motors 5 ′ and 5 ″ are shown on the front axles of the left and right front wheels 23 by a well-known method, as shown in FIG. An in-wheel motor can also be provided. In addition, the electric motors 5 ′ and 5 ″ turn on and off the drive of the motor shafts 5a ′ and 5a ″ (only 5a ′ is shown in the drawing) by the same clutch 5c ′ as described above. In this case, the front axle case 2 'can be supported on the frames 22a and 22b via brackets.

  Further, as shown in FIG. 13, the electric motors 5 ′ and (5 ″) are connected to the controller C via the inverter I, respectively, and the slip detector 11 and the torque detectors 12a and 12b described above, the angle The detector 13 and the front wheel drive switch 14 are connected to the controller C.

  Then, the controller C turns on and off the driving of the left and right electric motors 5 ′ and 5 ″ based on detection information from the slip detector 11, the torque detectors 12a and 12b, the angle detector 13, the front wheel drive switch 14 and the like. At this time, as described above, the left and right electric motors 5 ′ and 5 ″ are rotated at a predetermined number of rotations corresponding to the vehicle speed, for example, via the inverter I, and the controller C operates the clutch 5c and connects the clutch 5c. Then, since each front axle 23a rotates by rotation of motor shaft 5a ', 5a' ', the front wheel 23 drives.

  In addition to the above, based on the detection information from the angle detector 13, the controller C connects the motor shafts 5 a ′, 5 a ″ of the left and right electric motors 5 ′, 5 ″ via the inverter I to the vehicle body. The vehicle body can be smoothly turned by giving a rotation difference according to the turning radius and changing the rotation speed of the left and right front wheels 23 without using a differential.

  With such a configuration, the left and right front wheels 23 can be separately driven by the electric motors 5 ′ and 5 ″, respectively, and the differential gear installed in the front axle case 2 as in the prior art, A shaft, a kingpin, a final gear, etc. are not required, cost can be reduced, and the drive configuration of the front wheels 23 can be simplified.

  The in-wheel electric motors 5 ′ and 5 ″ described above are not limited to the outer rotor type, and may be an inner rotor type.

  As described above in detail, the wheeled tractor 1 of this example includes the left and right front wheels 23 and the rear wheels 24 on the front and rear of the vehicle, and transmits the power of the engine 40 installed on the vehicle body frame 22 via the transmission case 42. In addition to being transmitted to the wheels 24, the front wheel 23 is steered by a steering operation to turn the vehicle, and an electric motor 5 driven by the electric power of the battery 4 is installed near the front wheel 23. The controller C is connected to the controller C via the inverter I, and the driving of the electric motor 5 is controlled by the controller C based on the traveling load state of the rear wheel 24 and the turning state of the vehicle, and the front wheel 23 is driven by the electric motor 5. Is.

  In the above-described example, the wheel type tractor having the rear wheel drive / four wheel drive switching mechanism as the agricultural work machine has been described. However, the present invention is not limited to this, and the tractor excavator as the construction work machine, etc. The present invention can be applied to a wheeled tractor having any rear wheel drive / four wheel drive switching mechanism.

DESCRIPTION OF SYMBOLS 2 Front axle case 3 Battery case 4 Battery 5 Electric motor 5a Motor shaft 5b Bevel gear 5c Clutch 7 Differential device 7b Ring gear 11a, 11b, 11c Speed detector 12a, 12b Torque detector 13 Angle detector 22 Body frame 23 Front wheel 24 Rear wheel 29 Steering handle 29a Steering shaft 76 Sub-transmission shaft I Inverter s Stay

Claims (10)

Front and rear wheels on the front and rear of the vehicle,
In a wheeled work vehicle that transmits the power of an engine installed on a vehicle body frame to the rear wheel via a transmission case and steers the vehicle by steering the front wheel by a steering operation.
In the vicinity of the front wheel, an electric motor driven by battery power is installed, and the electric motor is connected to the controller via an inverter,
A wheeled work vehicle, wherein the controller controls the drive of the electric motor based on the traveling load state of the rear wheel and the turning state of the vehicle, and the front wheel is driven by the electric motor.   The wheeled work vehicle according to claim 1, wherein the electric motor is installed on a front surface, a rear surface, or an upper surface of a center portion of a front axle case to which the front wheel is attached.   The wheeled work vehicle according to claim 1, wherein the electric motor has the motor shaft connected to a ring gear of a differential gear provided in the front axle case.   The wheel type work vehicle according to claim 1, wherein the battery is installed in each of a plurality of battery cases attached to the body frame via a support member.   2. The wheeled work vehicle according to claim 1, wherein the battery is disposed in the vicinity of an ascending / descending step that assists in ascending and descending the vehicle, and below a control unit that controls the vehicle.   The vehicle is provided with a slip detector that detects a slip state of the rear wheel, and the slip detector is connected to the controller. Based on detection information of the slip detector, the controller The wheeled work vehicle according to claim 1, wherein the motor is driven and controlled.   The slip detector comprises a rotational speed detector that detects the rotational speed of the rear wheel, a vehicle speed detector that detects an actual speed of the vehicle, and a distance detector that detects a moving speed of the vehicle, Based on the calculated value, the ratio of the actual rotational speed to the normal rotational speed of the rear wheel is calculated from the actual speed of the vehicle detected by the vehicle speed detector and the traveling distance of the vehicle detected by the distance detector. 7. The wheeled work vehicle according to claim 1, wherein the slip state of the rear wheel is determined.   A torque detector for detecting a load torque applied to the rear wheel is installed on the drive shaft of the rear wheel, the torque detector is connected to the controller, and the controller is based on detection information of the torque detector. The wheel type work vehicle according to claim 1, wherein the electric motor is driven and controlled.   The steering is provided with an angle detector that detects a steering angle of the steering, and the angle detector is connected to the controller. Based on detection information of the angle detector, the controller The wheeled work vehicle according to claim 1, wherein the electric motor is driven and controlled at a predetermined vehicle speed or less.   The wheeled work vehicle according to claim 1, wherein the electric motor is separately attached to both ends of the front axle case, and a motor shaft of the electric motor is a front axle of the front wheel.

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