JP2004125123A - Transmission structure of traveling work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make compact a two-directional clutch and improve durability by improving the transmission structure of a traveling work vehicle having the two-directional clutch, preventing vibration and noise from occurring by a power transmission shaft and a joint when the traveling work vehicle turns, and avoiding damage to a road surface and a sod. <P>SOLUTION: A four-wheel drive type work vehicle for transmitting power from a power source 26 to front/rear wheels 4, 5 via an HST (hydrostatic continuously variable transmission) 14a transmits power to a steering wheel 4, 4 via the two-way clutch 60 on a motor shaft 36 for interlocking and connecting a hydraulic motor 32. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission structure of a traveling work vehicle including a two-way clutch.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a traveling work vehicle such as a tractor that allows a work machine to be connected to the rear or abdomen of a vehicle body and pulls and drives the work machine to perform various works has been known. For example, as a general configuration of a tractor, there is a configuration in which an engine is disposed at a front portion of a vehicle body, and a transmission for inputting the power of the engine, shifting the power, and transmitting the transmission to a rear axle is disposed at the rear portion of the vehicle body. The transmission includes a mechanism for shifting and connecting power to and from the rear axle and the PTO shaft, such as an HST (hydrostatic continuously variable transmission), an auxiliary transmission, a PTO clutch device, and a PTO transmission. In this configuration, the transmission is provided with an input shaft at a front portion thereof, and a PTO shaft for supporting a rear axle and driving a work machine is disposed at a rear portion. A power transmission structure is configured such that the power of the engine input from the front is branched and transmitted to the rear rear axle and the PTO shaft, and transmitted from the input shaft to the front wheels via the power transmission shaft. ing.
In such a four-wheel drive traveling work vehicle, when a turning operation is performed by steering the engine-side wheels to the left and right, the steering wheel is steered due to a difference between the inner and outer wheels of the steered wheels and the main drive wheels. The wheel on the wheel side tries to rotate at a higher speed than the wheel on the main drive wheel side. Therefore, there has been proposed a transmission structure of a traveling work vehicle including a two-way clutch that allows a state in which a wheel on a steered wheel rotates faster than a wheel on a main drive wheel in a forward / reverse state. For example, as described in Patent Literature 1 below, a transmission structure in which a two-way clutch is disposed in a power input portion of an axle case that supports steered wheels.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-132045
[Problems to be solved by the invention]
However, in the power transmission structure of the work vehicle described in Patent Document 1, the rotational torque is transmitted to the power transmission shaft after being decelerated from the motor shaft that is interlocked with the hydraulic motor. The torque increases and the power transmission shaft needs to be enlarged. Therefore, in order to obtain sufficient durability, the size of the two-way clutch must be increased, and it has been difficult to reduce the size of the two-way clutch.
Therefore, in the present invention, when the traveling work vehicle is turning, vibration and noise generated by the power transmission shaft and the joint are prevented, damage to the road surface and turf is suppressed, and the two-way clutch is reduced in size. It is an object to improve durability. It is another object of the present invention to reduce a turning radius by a forced four-wheel drive device that operates at an arbitrary steering angle or more.
[0005]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
[0006]
That is, in the four-wheel drive type working vehicle transmitting power from a power source to front and rear wheels via HST, a two-way clutch is provided on a motor shaft interlockingly connected to a hydraulic motor. The power is transmitted to the steered wheels via a clutch.
[0007]
In a four-wheel drive type working vehicle that transmits power from a power source to front and rear wheels via an HST, a motor that is provided with a steering wheel drive unit outside an HST center case and is interlocked with a hydraulic motor is provided. A two-way clutch is provided between the shaft and a power transmission shaft to the steered wheels.
[0008]
According to a third aspect of the present invention, in the traveling work vehicle according to the second aspect, a two-way clutch and a speed increasing mechanism are provided between a motor shaft linked to the hydraulic motor and a power transmission shaft to the steered wheels. .
[0009]
According to a fourth aspect of the present invention, in the traveling work vehicle, when a two-way clutch and a steering angle exceed a given angle between a motor shaft interlocked to a hydraulic motor and a power transmission shaft to a steered wheel, the speed increasing side is increased. The transmission has a speed change mechanism.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the invention will be described. Further, the configuration of the present invention is not limited to the illustrated example, and may be a configuration built in the transmission case, and may be configured on the steered wheel side.
1 is an overall side view of the tractor, FIG. 2 is a skeleton diagram showing a drive transmission path, FIG. 3 is a side sectional view of a transmission case, FIG. 4 is a side sectional view of a two-way clutch, and FIG. FIG. 6 is a side view of a two-way clutch according to another embodiment. FIG. 7 is a skeleton diagram showing a drive transmission path in the second embodiment. FIG. 8 is a side sectional view of a transmission case in the second embodiment. FIG. 10 is a side sectional view of a two-way clutch according to a second embodiment, FIG. 10 is a skeleton diagram showing a drive transmission path of another embodiment, FIG. 11 is a skeleton view showing a drive transmission path of a third embodiment, and FIG. It is a side sectional view of the two-way clutch in an example.
[0011]
As shown in FIG. 1, in the tractor 1, left and right vehicle frames 3 are arranged along the front-rear direction, and the front of the transmission case 29 of the transmission 14 is attached to the rear end of the vehicle frame 3. Rear axle cases 15 are arranged on the side surfaces. Reference numeral 2 denotes a transmission cover.
A mower 140 is supported on the abdomen of the vehicle body (mid-mount mower), and a mid-PTO shaft 25 for driving the mower 140 is supported by a cover 29c attached to the bottom surface of the transmission case 29. It is projected forward. The mower 140 is configured to support an input shaft 141 at its upper part, and the input shaft 141 and the mid-PTO shaft 25 are connected via a transmission shaft 142 and a universal joint.
[0012]
A front axle case 12 is supported at a lower front portion of the vehicle frame 3, and front wheels 4 are suspended at left and right ends of the front axle case 12. The left and right rear axle cases 15 support a rear axle 16, respectively, and rear wheels 5.5 are attached to the outer ends of the pair of left and right rear axles 16, 16, respectively.
[0013]
As shown in FIGS. 2 and 3, the transmission 14 includes a transmission case 29, and a hydrostatic stepless transmission (hereinafter, referred to as "HST") 14a as a main transmission mechanism is provided on a front surface thereof. , Which protrude and support the input shaft 14b forward. A front wheel drive output shaft 57 projects from the front surface of the transmission case 29 and is supported below the HST 14a.
[0014]
A flat center section 30 is mounted upright on the front surface of the transmission case 29, and a pump mounting surface is formed on the rear upper side of the center section 30 and a motor mounting surface is formed on the lower front side. An HST housing 14c is formed in an upper rear portion of the center section 30 and in a front portion of the transmission case 29, and an axial piston type hydraulic pump 31 to be described later is housed in the HST housing 14c. An HST housing 14d is mounted on the front surface, a hydraulic motor 32 is housed in the HST housing 14d, and the HST 14a is configured by fluidly connecting the hydraulic pump 31 and the hydraulic motor 32.
Further, a two-way clutch 60 is disposed in front of an HST case including the HST housing 14c and the HST housing 14d.
[0015]
Here, the hydraulic pump 31 will be described.
As shown in FIG. 3, the input shaft 14b, which is also used as a pump shaft, is supported at the center of the pump attachment surface, and a cylinder block 33 is fitted to the input shaft 14b so as to be relatively non-rotatable. The section 30 is rotatably and slidably mounted on the pump mounting surface. A plurality of cylinder holes are formed in the cylinder block 33, and a piston 34 is fitted in each of the cylinder holes via a biasing spring so as to be slidable. The heads of the piston groups 34, 34,... Are in contact with the movable swash plate 35, and by changing the inclination angle of the movable swash plate 35, the stroke of the piston 34 is changed, so that the discharge volume is stepless. It can be changed.
[0016]
A hydraulic oil circulation oil passage (not shown) is formed in the center section 30 so that the hydraulic oil discharged from the hydraulic pump 31 is supplied to the hydraulic motor 32.
[0017]
Next, the hydraulic motor 32 will be described.
As shown in FIG. 3, a motor shaft 36 disposed below and parallel to the input shaft 14b is supported at the center of the motor mounting surface, and a cylinder block 37 is fitted to the motor shaft 36 so as to be relatively non-rotatable. The cylinder block 37 is rotatably slidable with respect to the motor mounting surface of the center section 30. A plurality of cylinder holes are formed in the cylinder block 37, and a piston 38 is fitted in each of the cylinder holes via an urging spring so as to be reciprocally movable. The heads of the pistons 38 are in contact with a fixed swash plate 39 so that the motor shaft 36 can rotate at a speed corresponding to the discharge volume of the hydraulic pump 31.
[0018]
Power is transmitted to the HST 14a from the engine 26, which is a driving source, via the input shaft 14b and the charge pump 27, and the hydraulic pump 31 is driven. The rear end of the input shaft 14b is connected to the clutch shaft 28, and the rear end of the clutch shaft 28 is freely connectable to the PTO input shaft 46 via the PTO clutch 41. A gear 47 is fixed to the rear end of the PTO input shaft 46, and power is transmitted from the gear 47 to the mid PTO shaft 25 via gears 48 and 49. The mid PTO shaft 25 protrudes forward from the transmission case below the rear axle 16 and drives the mower 140.
[0019]
Below the hydraulic pump 31, a motor shaft 36 is formed integrally with the cylinder block 33 of the hydraulic motor 32, and a two-way clutch 60 is installed at the front end of the motor shaft 36. The power from the hydraulic motor 32 is transmitted from the two-way clutch 60 and the power transmission shaft 13 to the front differential 43 in the front axle case 12 via the joints 19, and the differential yokes on both sides of the front differential 43. The front wheels 4 are driven via the shafts 44 and the final deceleration mechanism.
[0020]
On the other hand, a rear end of the motor shaft 50 penetrates through the HST housing 14d and protrudes into the transmission case 29 to form a pinion 59, and the pinion 59 is engaged with the bevel gear 68. The bevel gear 68 is fixedly mounted on an intermediate brake shaft 55 which is horizontally rotatable in the left-right direction. A small gear 69 provided adjacent to the bevel gear 68 meshes with a large gear 70. The large gear 70 is fixed to a differential case of the rear differential 24, and the differential case is rotatably supported on the rear axle 16. Thus, the power transmitted from the motor shaft 36 is transmitted to the rear differential 24, and the rear differential 24 drives the rear wheels 5.5 via the rear axles 16/16 on both sides. .
[0021]
Next, the two-way clutch 60 will be described. However, the two-way clutch is not limited to the one described below, but may be any clutch having an equivalent function.
As shown in FIGS. 3 and 4, the two-way clutch 60 is provided on the motor shaft 36 on the front side of the body of the HST housing 14 d that houses the hydraulic motor 32. The two-way clutch 60 includes a cam 61 serving as an input member, a transmission case 62 serving as an output member, and a plurality of torque transmitting members interposed between an outer peripheral surface of the cam 61 and an inner peripheral surface of the transmission case 62. , A holder 64 for holding the rollers 63, 63,..., And a friction member 65 interposed between the holder 64 and the cam 61.
[0022]
A transmission case 62 is rotatably fitted to one end of the motor shaft 36, and a cam 61 is fixedly provided. The input rotation torque from the hydraulic motor 32 is input to the cam 61 via the motor shaft 36. It is configured as follows. An output shaft 62c is integrally formed on one end side of the transmission case 62, and the output shaft 62c is interlocked with the power transmission shaft 13 via the joint 19 so as to be able to transmit rotational torque.
Instead of forming the output shaft 62c at one end of the transmission case 62 as described above, a flange 71 is fixed to the transmission case 67 as shown in FIG. 6, and the flange 71 and the power transmission shaft 13 are directly connected to each other. It is also possible to adopt a configuration of interlocking connection with. Thereby, the joint which is a source of vibration and noise can be omitted.
[0023]
The cam 61 is fitted to the motor shaft 36 so as to be relatively non-rotatable, and has cam surfaces 61a formed on the outer periphery thereof so as to correspond to the number of rollers 63 arranged. An accommodation portion 61b for accommodating a later-described retainer is provided at an end of the cam 61.
[0024]
The transmission case 62 is formed in a substantially cup shape, and includes a cup-shaped portion 62a on one side and a hollow shaft-shaped portion 62b integrally formed with an output shaft 62c at an end on the other side. The shaft portion 62b is rotatably mounted on the motor shaft 36. The inner periphery of the cup-shaped portion 62a is formed as a circumferential surface, and the circumferential surface and the cam surface 61a of the cam 61 are arranged so as to face each other at a predetermined interval.
[0025]
The retainer 64 is composed of a main portion 64a interposed between the outer periphery of the cam 61 and the inner periphery of the cup-shaped portion 62a of the transmission case 62, and an annular portion 64b fitted to the housing portion 61b of the cam 61. The main portion 64a is provided with a plurality of grooves for accommodating the rollers 63.
[0026]
Further, the friction member 65 is brought into contact with the retainer 40 and is fitted with a predetermined fitting force to the housing portion 61b of the cam 61. When an external force exceeding this fitting force is received in the rotation direction, the friction member 65 It is configured to cause a slip with respect to.
[0027]
The roller 63 is housed in the groove of the retainer 40 and is disposed between the cam surface 61a of the cam 61 and the circumferential surface 62d of the transmission case 62. The diameter of the roller 63 is set smaller than the radial dimension between the rotational center position of the cam surface 61 a of the cam 61 and the circumferential surface 62 d of the transmission case 62. Therefore, as shown in FIG. 5A, when the roller 63 is located at the center position in the rotation direction of the cam surface 61a, the roller 63 can separate from both the cam surface 61a and the circumferential surface 62d and roll freely. However, as shown in FIG. 5B, when the cam surface 61a moves by a predetermined amount in the left rotation direction (right rotation direction) from the center position of the cam surface 61a, it engages with both the cam surface 61a and the circumferential surface 62d.
[0028]
The garter spring 66 includes an annular portion 66a and a pair of engagement portions 66b extending radially inward from both ends of the annular portion 66a. The annular portion 66a engages with the rollers 63, 63. The engaging portion 66b is locked by the locking portion 61c of the cam.
[0029]
When no external force acts on the retainer 64 in the rotational direction, the rotational position of the retainer 64 with respect to the cam 34 is centered at the position shown in FIG. (Hereinafter, the position shown in FIG. 3A is referred to as a "neutral position.") At this time, the roller 63 is located at the center position in the rotation direction of the cam surface 61a, and separates from both the cam surface 61a and the circumferential surface 62d. I do.
[0030]
In this state, when an external force acts on the retainer 64 in the rotation direction, the garter spring 66 is bent by an amount corresponding to the external force, and the retainer 64 relatively rotates with respect to the cam 61 as shown in FIG. . By the relative rotation of the retainer 64, the roller 63 held by the retainer 64 receives a force from the retainer 64 and moves by a predetermined amount in the rotational direction from the center position in the rotational direction of the cam surface 61a, and the roller 63 moves in a circle with the cam surface 61a. It engages with both of the peripheral surfaces 62d. (Hereinafter, the position shown in FIG. 3B is referred to as a “torque transmitting position.”) As a result, the rotational torque is transmitted from the cam 61 to the transmission case 62 via the roller 63.
[0031]
When the external force in the rotational direction described above disappears, the retainer 64 is relatively rotated with respect to the cam 61 by the elastic force of the garter spring 52, and is centered at the neutral position shown in FIG.
[0032]
In such a configuration, when power is transmitted from the engine 26 via the HST 14a, the rotational torque of the hydraulic motor 32 is input to the cam 61 via the motor shaft 36, and the cam 61 rotates. Then, the retainer 64 connected to the cam 61 via the garter spring 52 in the rotation direction rotates with the rotation of the cam 61. At this time, since the friction member 65 is constrained in the rotational direction, the friction member 65 slides with respect to the retainer 40, and the retainer 64 receives resistance from the friction member 65 due to the slip. Therefore, the engaging portion 66b of the garter spring 66 bends in the rotation direction, and the retainer 64 rotates relative to the cam 61 accordingly. That is, the retainer 64 rotates with a delay with respect to the cam 61. Due to the relative rotation of the retainer 64, the clutch is automatically switched to the torque transmitting position shown in FIG.
[0033]
When the clutch is switched to the torque transmission position shown in FIG. 3B, the forward / reverse rotation torque of the hydraulic motor 32 is input to the cam 61 of the two-way clutch 60 via the motor shaft 36, and the cam 61, the roller 63, The power is transmitted to an output shaft 62c formed integrally with the transmission case 62 via a torque transmission path of the transmission case 62. Then, rotational torque is transmitted from the output shaft 62c to the front differential 43 via the joint 19, the power transmission shaft 13, and the like, and the front wheels 4 are driven.
[0034]
Further, when the engine 26 stops and the rotation of the cam 61 and the retainer 64 stops in the above-mentioned state, the resistance of the friction member 65 disappears, and the retainer 64 is moved against the cam 61 by the elastic restoring force of the garter spring 66. , And is automatically centered at the neutral position shown in FIG. When the retainer 64 is thus centered at the neutral position shown in FIG. 3A, the torque transmission path is cut off between the cam 61 and the transmission case 62, and the transmission case 62 is released from the input system. You.
[0035]
With this configuration, vibration and noise generated by the power transmission shaft 13 and the joint 19 during turning of the traveling work vehicle can be prevented. Further, by installing the two-way clutch on the motor shaft having a relatively low rotational torque, the two-way clutch can be downsized, and the durability of the two-way clutch and the compact layout of the machine can be achieved.
[0036]
Further, since the two-way clutch 60 is provided independently of the transmission case 29 and can be supplied with oil through the oil supply port 62e provided in the transmission case 62, the amount of oil can be controlled only by the two-way clutch 60. Malfunction of the two-way clutch 60 due to a change in the amount can be prevented.
[0037]
Next, a second embodiment of the power transmission structure will be described.
As shown in FIGS. 7 to 9, a gear 74 is fixedly mounted on the tip of the motor shaft 36 inserted through a case 72 attached to the front of the transmission case 29, and a gear 75 is meshed with the gear 74. The gear 75 is fixed to one end of the intermediate shaft 76, and a two-way clutch 73 is provided at the other end of the intermediate shaft 76. The gear 78 is meshed with the gear 81a via the two-way clutch 73. The gear 78 is fixed to one end of the output shaft 79, and the output shaft 79 is interlocked to the power transmission shaft 42 by the joint 19. Power is transmitted from the motor shaft 36 to the power transmission shaft 42.
[0038]
As shown in FIG. 9, the two-way clutch 73 is interposed between a cam 80 as an input member, a transmission case 81 as an output member, and an outer peripheral surface of the cam 80 and an inner peripheral surface of the transmission case 81. , Which are torque transmitting members, a retainer 83 for retaining the rollers 82, and a friction member 84 interposed between the retainer 83 and the cam. Have been. The two-way clutch 73 is configured in the same manner as the above-described first embodiment, except that the gear 81a is formed at one end of the transmission case 81 instead of the output shaft. Omitted.
[0039]
With this configuration, vibration and noise generated by the power transmission shaft 42 and the joint 19 during turning of the traveling work vehicle can be prevented. Means for providing a two-way clutch 73 by providing an intermediate shaft 76 between the motor shaft 36 interlockingly connected to the hydraulic motor 32 and the power transmission shaft 13 to the steered wheels 4 Thus, the size of the two-way clutch can be further reduced, and if necessary, the layout can be matched to the layout of the machine by changing the reduction ratio of the power transmission unit.
[0040]
Further, as shown in FIG. 10, a two-way clutch 85 and a two-stage clutch of deceleration and acceleration are provided between the motor shaft 36 interlockingly connected to the hydraulic motor 32 and the power transmission shaft 45 to the steered wheels 4. A power transmission structure may be provided with the transmission mechanism 86. The transmission mechanism 86 is provided with a two-way clutch 85 on the output side, and is biased to the deceleration side when traveling straight, so that when the steering angle exceeds an arbitrary angle, it is shifted to the speed increasing side. The transmission includes a shift clutch 86a that is linked to a steering system. The transmission mechanism 86 can drive the steered wheels 4 and 4 even during turning by driving the steered wheels 4 and 4 at a speed higher than the speed of the reverse drive from the steered wheels 4 and 4, thereby driving the steered wheels. The turning radius can be reduced by the steering wheel assist that gives power.
[0041]
Next, a third embodiment of the power transmission structure will be described.
As shown in FIGS. 11 and 12, the two-way clutch 90 is provided at the power input portion of the front axle case 12, and is configured to perform deceleration by the spur gear train after the output from the two-way clutch 90. A cam 91 serving as an input member, a transmission case 92 serving as an output member, and a plurality of rollers 93 serving as torque transmitting members interposed between an outer peripheral surface of the cam 91 and an inner peripheral surface of the transmission case 92. , And a holder 94 for holding rollers 93, 93, and a friction member 95, and a cam 91 is fixed to an input shaft 96 which is interlocked to the power transmission shaft 51 via a joint 19. On the other hand, a gear 92a formed in the transmission case 92 meshes with the input gear 97 to transmit power to the front differential 43 to drive the front wheels 4. Since the two-way clutch has substantially the same configuration as that of the first embodiment, the description thereof is omitted.
[0042]
Therefore, in general, when the traveling work vehicle turns, the steered wheels rotate faster than the main drive wheels, so that the power is transmitted from the steered wheels so as to drive the power transmission shaft in reverse. By providing the two-way clutch, it is possible to prevent power from being transmitted from the steered wheels 4 to the power transmission shaft 13, so that vibration and noise generated by the power transmission shaft 51 and the joint 19 are prevented. And the damage to the road surface and turf that occurs at the time of turning can be suppressed.
[0043]
【The invention's effect】
The present invention is configured as described above, and has the following effects.
[0044]
More specifically, in a four-wheel drive working vehicle that transmits power from a power source to front and rear wheels via an HST, a two-way clutch is provided on a motor shaft that is interlocked with a hydraulic motor. Since the power is transmitted to the steered wheels via the directional clutch, vibration and noise generated by the power transmission shaft and the joint during turning of the traveling work vehicle can be prevented. Further, it is possible to suppress damage to the road surface and the turf surface caused by the imbalance between the front and rear wheel speed ratios. Further, since the rotational torque on the motor shaft is relatively low, the size of the two-way clutch can be reduced, and the durability of the two-way clutch and the compact layout of the machine can be achieved.
[0045]
According to a second aspect of the present invention, in a four-wheel drive type work vehicle that transmits power from a power source to front and rear wheels via an HST, a steering wheel drive unit is provided outside an HST center case and is linked to a hydraulic motor. Since the two-way clutch is provided between the motor shaft and the power transmission shaft to the steered wheels, it is possible to prevent vibration and noise generated by the power transmission shaft and the joint when the traveling work vehicle turns. Further, it is possible to suppress damage to the road surface and the turf surface caused by the imbalance between the front and rear wheel speed ratios. Further, the size of the two-way clutch can be reduced, and if necessary, the reduction ratio of the power transmission unit can be changed to match the layout of the machine.
[0046]
According to a third aspect of the present invention, in the traveling work vehicle of the second aspect, a two-way clutch and a speed increasing mechanism are provided between a motor shaft interlockingly connected to the hydraulic motor and a power transmission shaft to the steered wheels. Vibration and noise generated by the power transmission shaft and the joint when the traveling work vehicle turns can be prevented when the traveling work vehicle turns. Further, it is possible to suppress damage to the road surface and the turf surface caused by the imbalance between the front and rear wheel speed ratios. Further, the size of the two-way clutch can be reduced, and if necessary, the reduction ratio of the power transmission unit can be changed to match the layout of the machine.
[0047]
According to a fourth aspect of the present invention, in the traveling work vehicle, when a two-way clutch and a steering angle exceed an arbitrary angle between a motor shaft interlocked with a hydraulic motor and a power transmission shaft to a steered wheel, the speed is increased. Since the shift mechanism is shifted to the side, the steered wheels can be driven even during turning by making a configuration in which the speed change mechanism can drive at a speed higher than the speed of the reverse drive from the steered wheels. Further, the turning radius can be further reduced by the steering wheel assist that applies a driving force to the steering wheel.
[Brief description of the drawings]
FIG. 1 is an overall side view of a tractor.
FIG. 2 is a skeleton diagram showing a drive transmission path.
FIG. 3 is a side sectional view of a transmission case.
FIG. 4 is a side sectional view of the two-way clutch.
FIG. 5 is a front sectional view of the two-way clutch. (A) The figure which shows the neutral position of a retainer. (B) The figure which shows a torque transmission position.
FIG. 6 is a side view of a two-way clutch according to another embodiment.
FIG. 7 is a skeleton diagram showing a drive transmission path in the second embodiment.
FIG. 8 is a side sectional view of a transmission case in the second embodiment.
FIG. 9 is a side sectional view of a two-way clutch according to the second embodiment.
FIG. 10 is a skeleton diagram showing a drive transmission path according to another embodiment.
FIG. 11 is a skeleton diagram showing a drive transmission path in the third embodiment.
FIG. 12 is a side sectional view of a two-way clutch according to a third embodiment.
[Explanation of symbols]
4 Steering wheel 5 Main drive wheel 14a HST
26 engine 32 hydraulic motor 36 motor shaft 60 two-way clutch

Claims (4)

In a four-wheel drive type work vehicle that transmits power from a power source to front and rear wheels via an HST, a two-way clutch is provided on a motor shaft that is interlocked with a hydraulic motor, and a steered wheel is provided via the two-way clutch. A power transmission structure for a traveling work vehicle, wherein power is transmitted to the vehicle. In a four-wheel drive type work vehicle that transmits power from a power source to front and rear wheels via an HST, a steering wheel drive unit is provided outside an HST case to provide a motor shaft and a steering wheel that are operatively connected to a hydraulic motor. A transmission structure for a traveling work vehicle, comprising a two-way clutch between the power transmission shaft and the power transmission shaft. 3. The traveling work vehicle according to claim 2, further comprising a two-way clutch and a speed increasing mechanism between a motor shaft connected to the hydraulic motor and a power transmission shaft to the steered wheels. Transmission structure. In a traveling work vehicle, a two-way clutch and a transmission mechanism that is shifted to a speed increasing side between a motor shaft interlockingly connected to a hydraulic motor and a power transmission shaft to a steered wheel when a steering angle exceeds an arbitrary angle. A power transmission for a traveling work vehicle, comprising:

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