JP2000025639A - Steering and driving device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a vehicle so as to easily change the direction of driving force to be inputted into HSTs, in the vehicle provided with a steering driving device capable of transmitting and driving left and right axles by having two pairs of HSTs and two differential devices connected with each output shaft and interlocking and connecting the two pairs of differential devices. SOLUTION: By providing each gear on pump shafts 81 of two HSTs, interlocking and connecting the gears by a gear train, fixedly providing two pulleys 20a, 20b on an input shaft to this gear train and an output shaft 11a of a prime mover, respectively, laying belts 71 in parallel between pulleys on one side and laying other belts 72 in a cross-shape, two pairs of belt transmission mechanisms are constituted. These two pairs of belt transmission mechanisms are provided with clutches for forwarding and backwarding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a configuration in which one of two HSTs is used for steering and the other is used for traveling, and the respective outputs are connected to drive a pair of left and right axles. The present invention relates to a technique for transmitting power to an input shaft of a transmission.

[0002]

2. Description of the Related Art Conventionally, two pairs of HSTs are connected left and right, an axle protrudes outward from each HST, wheels are fixed to ends of both axles, and the angle of the swash plate of the HST is adjusted. A technique of changing the left and right wheels to drive is known. For example, the technology of US Pat. No. 4,782,650. In this technique, when traveling straight, the traveling speeds of the left and right HSTs are the same, and when turning, the traveling speeds of the left and right wheels are different.

[0003]

However, in the conventional traveling vehicle, if the output rotations of the left and right HSTs do not match at all, the vehicle cannot go straight, it takes time for adjustment at the time of shipment, and the parts and assembly errors are reduced. It needed to be more accurate. Also, if there is a difference in capacity between the hydraulic pump and the hydraulic motor, the right and left turning feelings are different, and the traveling vehicle is very difficult to steer. Also, when working while turning, the conventional traveling vehicle has a large turning radius,
For example, in the case of work requiring a small turn such as lawn mowing around a grove, it is necessary to travel the same position many times and work, and the work efficiency has deteriorated. In order to solve the above-mentioned problem, one of the two HSTs is used for steering and the other HST is used for traveling, and the respective outputs are transmitted to the differential gear device. When a pair of left and right axles are driven and the turning direction of the steering wheel is matched with the turning direction of the steering wheel when the pair of left and right axles are driven, the turning direction of the steering wheel is opposite to the turning direction of the steering wheel. He turned backwards and turned backwards, making it very difficult to turn in reverse and took a long time to get used to.

[0004]

The present invention uses the following means to solve the problems. That is, in claim 1, two sets of a hydraulic pump and a hydraulic motor (HST)
A steering drive device having two differentials connected to respective output shafts, and the two sets of differentials being interlockingly connected so that the left and right axles can be shifted. HST
A gear is provided on each of the pump shafts, and the gear train is interlocked and connected, and two pulleys are respectively fixed on the input shaft to the gear train and the output shaft of the motor, and a belt is hung between one pulley in parallel. The other belt is cross-linked to form two sets of belt transmission mechanisms, and the two sets of belt transmission mechanisms are provided with forward and reverse clutches. According to a second aspect of the present invention, a tensioner is disposed in each of the two sets of belt transmission mechanisms, and the driving direction to the input shaft can be changed by using the clutch as a belt tension type clutch. According to a third aspect of the present invention, an electromagnetic clutch is interposed between two pulleys arranged on one of the input shaft and the output shaft of the prime mover, and the operation of one of the electromagnetic clutches is performed. Thus, the driving direction can be changed. According to a fourth aspect of the present invention, there are provided two sets of HSTs and two differentials connected to respective output shafts. A steering drive device capable of providing a gear and a pulley on each of two HST pump shafts and interlockingly connecting them by a gear train, and a pulley provided on both pump shafts and an output shaft of a prime mover. A belt is wound between the provided pulleys, and an electromagnetic clutch is interposed between the pump shafts and the pulleys of the two HSTs, and the drive direction of each HST to the input shaft can be changed by operating the electromagnetic clutches. It is what was constituted.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The problems and means to be solved by the present invention are as described above. Next, an embodiment in which the present invention shown in the attached drawings is applied to a mower will be described. FIG. 1 is an overall side view of a mower employing a steering drive device of the present invention, FIG. 2 is a perspective view of a main part showing a configuration for transmitting a driving force from an engine, and FIG. 3 is a second embodiment for transmitting a driving force from an engine. FIG. 4 is a front cross-sectional view of an HST, FIG. 5 is a front cross-sectional view of an HST as another embodiment of the gear train, and FIG. 6 is a main view showing a third embodiment for transmitting a driving force from an engine. Part perspective view, FIG.
FIG. 8 is a front cross-sectional view of the HST according to the third embodiment, FIG. 8 is a skeleton diagram illustrating a drive mechanism of a rear wheel, and FIG. 9 is a skeleton diagram illustrating a drive mechanism of a rear wheel according to a second embodiment.

Referring to FIG. 1, the entire structure of a lawn mower 1 equipped with a steering drive according to the present invention will be described. Vehicle chassis 1
A front column 13 is erected on a front portion of the vehicle 2, and a steering handle 14 is projected from the front column 13 as a steering operation tool. The front column 1
A speed change pedal 15 as a speed change operation tool and a brake pedal (not shown) are disposed on the side of the gear 3. A forward / reverse switching lever 5 is provided on a side portion of the front column 13, and the forward / backward switching lever 5 is set to a forward position F, a neutral position N, and a reverse position R. The forward / reverse switching lever 5 is configured to be able to switch between forward and backward travel of the body. On both front lower sides of the vehicle chassis 12, front wheels 16, 16 which are caster wheels serving as driven wheels, are arranged.

A seat 17 is mounted on the center of the vehicle chassis 12, and a mower 9 is disposed below the mower 9. The mower 9 is provided with a rotary blade in a case 19, and is provided with a pulley, a belt, and the like from an engine 11 described later. It is configured to be driven via a.
Further, the mower 9 can be moved up and down on the front part and the rear part of the case 19 by being connected to link mechanisms for elevating and lowering, respectively.
An engine 11 is mounted on a rear portion of the vehicle chassis 12 and covered with a bonnet. The engine 11 is a vertical type, and an output shaft 11a projects vertically downward, and an output pulley 20 is fixed to a lower end of the output shaft 11a. Has been established.

Next, the steering driving device 2 will be described.
Two sets of hydraulic pumps and hydraulic motors are driven from an output pulley 20 on the output shaft 11a through a drive direction changing mechanism 3 including a belt and a pulley, which will be described later, and an axle 31 is driven through two sets of differentials.・ Power is transmitted to 31. As shown in FIG. 4, the configuration of the steering drive device 2 in the housing 25 includes two sets of HSTs 21 and 22 including a hydraulic pump and a hydraulic motor, two sets of operating devices (not shown), and a pair of left and right axles. Is housed. The housing 25
A case 101 is placed and fixed on the upper part of the case.
1 houses a gear train.

Of the two sets of hydraulic pumps and hydraulic motors, one is a traveling HST 21 and the other is a steering HST 21.
In the HST 21, the driving force from the engine 11 is input to an input shaft 81 serving as a pump shaft. The upper and lower central portions of the input shaft 81 are rotatably supported by bearings fixed to the upper portion of the case 101, and the lower end of the input shaft 81 rotates on the upper surface of the center section 103 provided in the housing 25. It is freely pivoted.

[0010] A cylinder block 104 is provided on the center section 103, and the cylinder block 104 is fitted on the input shaft 81. The center of the cylinder block 104 is engaged with a spline groove provided below the input shaft 81, and is configured to be rotatable on the center section 103 together with the input shaft 81. A plurality of pistons 105 are slidably inserted into the cylinder block 104.
5 is urged upward by a spring disposed between the cylinder block 104 and the cylinder block 104. A movable swash plate 106 is in contact with the upper part of the piston 105. The hydraulic fluid is supplied to the hydraulic motor via an oil passage provided in the center section 103 so that hydraulic oil can be sucked and discharged by sliding the piston 105.

An arm 10 is provided on the side of the movable swash plate 106.
The base of the arm 109 is inserted and fixed to one end of the lever shaft 107. A central portion of the lever shaft 107 is rotatably supported by being inserted into the housing 25. A control lever 108 is fixed to the other end of the lever shaft 107, and the movable swash plate 106 is
Is configured to be rotatable. Thus, the variable displacement hydraulic pump 102a is configured. A fixed displacement hydraulic motor (not shown) is arranged on the other surface of the center section 103.

With the above configuration, the cylinder block 104 is rotated by the driving force input from the input shaft 81, and the angle of the movable swash plate 106 is adjusted by the control lever 108 fixed to the lever shaft 107. The sliding amount of the piston 105 is adjusted, the hydraulic oil discharge amount and the discharge direction of the hydraulic pump 102a are adjusted, and the rotation speed of the hydraulic motor connected to the hydraulic pump 102a can be adjusted.

The steering HST 22 includes the traveling HST 22.
The upper end of the pump shaft 121 is rotatably supported by a bearing fixed to the upper portion of the case 101, and the lower end of the pump shaft 121 is a center section disposed in the housing 25. 123 is pivotally supported on the upper surface. The center section 12
3, a cylinder block 124 is disposed, and the cylinder block 124 is inserted into the pump shaft 121. The inside of the cylinder block 124 meshes with a spline groove provided below the pump shaft 121, and is configured to be rotatable on the oil passage plate 123 together with the pump shaft 121. The cylinder block 12
A plurality of pistons 125 are slidably inserted in 4, and are urged upward by a spring disposed between the piston 125 and the cylinder block 124. The piston 1
A movable swash plate 126 is in contact with the upper portion of the movable swash plate 126, and the piston 125 is configured to be slidable on the bottom surface of the movable swash plate 126. The hydraulic fluid is configured to be capable of being sucked and discharged by sliding the piston 125, and the hydraulic fluid is connected to a hydraulic motor via an oil passage provided in the center section 123.

An arm 129 is provided on the side of the movable swash plate 126.
Are engaged, and the base of the arm 129 is connected to the lever shaft 1.
The central portion of the lever shaft 127 is rotatably supported by being inserted into the case 101. The other end of the lever shaft 127 has a control lever 1
The movable swash plate 126 is configured to be rotatable by the rotation of the control lever 128.

With the above configuration, the cylinder block 124 is rotated by the driving force input from the pump shaft 121, and the angle of the movable swash plate 126 is adjusted by the control lever 128, whereby the sliding amount of the piston 125 is reduced. By adjusting the hydraulic oil discharge amount and the discharge direction of the hydraulic pump 102b, the drive of the hydraulic motor connected to the hydraulic pump 102b can be adjusted.

Next, the HST 21 for traveling and the HST for steering
A gear train for transmitting power to ST22 will be described. A gear 111 is inserted and fixed in the upper and lower central portions of the input shaft 81 in the case 101, and a gear 113 is inserted and fixed in an upper part of the pump shaft 121. The input shaft 8
1 and a pump shaft 121, a support shaft 112a is rotatably supported vertically between the case 101 and the upper surface of the housing 25, and a gear 112 is fixed on the support shaft 112a. At a position between the gear 111 and the gear 113, they are engaged with each other. In this manner, a gear train is configured such that the driving force from the input shaft 81 can be transmitted from the gear 111 to the gear 113 via the gear 112.

Further, the gear train may be configured as shown in FIG. That is, the pump shaft 215 of the traveling HST 21 and the steering HST 21
22 between the pump shafts 221 and the lower part of the housing 2
5 is rotatably supported on the upper surface via a bearing, the upper portion protrudes upward from the case 201, and an intermediate portion thereof is rotatably supported on the case 201 via a bearing. A gear 212 is fixedly fitted to a lower portion of the input shaft 81b, and a gear 211 and a gear 213 are fixedly fitted to an upper portion of the pump shaft 215 and the pump shaft 221, respectively, so as to mesh with the gear 212, respectively. . The upper ends of the pump shaft 215 and the pump shaft 221 are rotatably supported by the case 201 via bearings, and are covered by the case 201.

With the above configuration, when the input shaft 81b is driven, the hydraulic pump 102a and the hydraulic pump 1 are driven.
02b can be driven, and the input shaft 81b
Gear 2 fixed to the gear 211 and the pump shaft 221 of the hydraulic pump 102b by a gear 212 fixed to the
Since the driving force can be transmitted to the pump 13, the rotation directions of the pump shaft 215 and the pump shaft 221 can be made the same.

That is, power can be transmitted from one input shaft to two sets of HSTs. The transmission configuration is simple, the vertical width can be reduced, and the HST hydraulic pump 102a
And the hydraulic pump 102b can be driven in the same direction.

Next, the driving mechanism of the driving wheels will be described. In FIG. 8, the hydraulic pump 102a of the HST 21 is fluidly connected to the hydraulic motor 102c,
The hydraulic motor 102c is driven by the supply of the hydraulic oil from the hydraulic motor 102a.
And the brake disc 35b are inserted and fixed.

A gear 34a is meshed with the gear 35, and the gear 34 is fixedly fitted on a support shaft on which the gear 34a is fixedly fitted. The gear 34 meshes with a center gear 32b fixed on a support shaft arranged on the same axis as the axle 31, and sun gears 32 are inserted at both ends of the support shaft into which the center gear 32b is inserted and fixed. Fitted and fixed.
A plurality of planet gears 31a
a are engaged with each other, and the planetary gears 31a
1 is rotatably supported by a carrier fixed to the inner end. The outer peripheral side of the planet gears 31a is meshed with the internal gear 33a.

On the other hand, the hydraulic motor 102 of the HST 22
A bevel gear 38 is inserted and fixed to the output shaft d, and bevel gears 37b are arranged and engaged on both sides of the bevel gear 38, and gears 37 are attached to a support shaft for inserting and fixing the bevel gears 37b. The gears 37 are loosely fitted on the axles 31.
33, and the planetary gear 3
An internal gear 33a meshing with 1a and 31a is fixed. In this configuration, when the bevel gear 38 is rotated by the driving of the hydraulic motor 102d, the directions of rotation of the bevel gears 37b are opposite to each other. When the gears 33 are driven from the bevel gears 37b and 37b, and the driving force is transmitted to the sun gears 32, the rotation speed of the axle 31 is increased on one side by a planetary gear mechanism, and the other side is increased by the planetary gear mechanism. It is decelerated and constitutes a differential mechanism.

For this reason, the steering handle 14 is rotated during traveling, the angle of the movable vehicle plate of the hydraulic pump 102b is changed, the hydraulic motor 102d is driven, and the gear 33
By driving the vehicle 33, the traveling direction of the body can be changed and the vehicle can be turned according to the difference between the driving speeds of the left and right axles 31.

Next, another embodiment of the differential mechanism will be described. In FIG. 9, a gear 41 and a brake disc 41b are fitted and fixed on an output shaft of a hydraulic motor 102c of the HST 21, and the gear 41 meshes with a gear 42,
A gear 42b is inserted and fixed to the other end of the support shaft for inserting and fixing the gear 42. A ring gear 43 is provided on the gear 42b.
Are engaged with the ring gear 43 so that the differential small gear 43b is orthogonal to the rotation axis of the ring gear 43.
43b is pivotally supported. The differential small gear 4
Reference numerals 3b and 43b mesh with a differential side gear 44 inserted and fixed to the axle 31. The traveling differential mechanism 50 is thus configured. Therefore, the axles 31
, The axles 31 can be rotated at a rotation speed equal to the rotation speed of the ring gear 43.

A gear 49 inserted and fixed to the output shaft of the hydraulic motor 102d of the HST 22 meshes with the ring gear 47, and the ring gear 47 is connected to the ring gear 47 so as to be orthogonal to the rotation axis of the ring gear 47. Moving small gear 47b / 47
b is pivotably supported. The differential small gear 47b
47b is a differential side gear 46a and a differential side gear 4
6b are engaged. A gear 46 is inserted and fixed to the other end of the support shaft in which the differential side gear 46a is inserted and fixed to one end, and the gear 46 meshes with a gear 45 inserted and fixed to the axle 31. The differential side gear 46b
A gear 46c is fitted and fixed to the other end of the support shaft having one end inserted and fixed, and the gear 46c meshes with the gear 48. The gear 48 meshes with a gear 45 fixedly fitted to the axle 31. Thus, the steering differential mechanism 51 is configured.

With this configuration, the drive wheels 30 can be driven in the forward and backward directions by rotating the shift pedal 15 and driving the hydraulic motor 102c by the hydraulic pump 102a.
Is rotated to change the angle of the movable axle of the hydraulic pump 102b and to drive the hydraulic motor 102d, whereby driving forces in mutually opposite directions are transmitted to the axles 31. A speed difference is generated in the driving speed, so that the traveling direction of the aircraft can be changed and the vehicle can turn.

Next, the driving direction changing mechanism 3 which is a main part of the present invention will be described. First, the first embodiment will be described with reference to FIG. A double pulley 20a and a pulley 20b are inserted and fixed to the output shaft 11a of the engine 11,
In front of the pulleys 20a and 20b, a pulley 8 fitted and fixed to an input shaft 81 of the steering driving device 2 is provided.
0a and a pulley 80b are provided. In this case, the electromagnetic crack 85 shown in FIGS. 4 and 5 is not provided, and the pulleys 80a and 80b are directly fixed to the input shafts 81 and 81b.

The belt 71 is wound around the pulley 20a and the pulley 80a with play. The belt 71
Is hung parallel to the pulley 20a and the pulley 80a. A tensioner 73 is provided between the pulley 20a and the pulley 80a. The tensioner 73 eliminates the play of the belt 71 (giving tension), and reduces the driving force of the pulley 20a by the pulley 80a.
When the tensioner 73 is not operated, the belt tension clutch is configured so that the pulley 20a does not drive the belt 71 and does not transmit the driving force to the pulley 80a. Make up.

The belt 72 is wound around the pulley 20b and the pulley 80b with play. The belt 72
Is crossed on the pulley 20b and the pulley 80b. The belt 72 has a guide 72a.
72b is in contact, the guide 72a is urging the belt 72 above the intersecting belt 72 upward, and the guide 72b is urging the belt 72 below the intersecting belt 72 downward. . For this reason, the belts 72 are prevented from contacting each other so that the life of the belts is extended. The pulley 20b and the pulley 80b
A tensioner 74 is disposed between the pulleys. The play of the belt 72 is eliminated (giving tension) by the tensioner 74, and the driving force of the pulley 20b is reduced by the pulley 8.
0b. Further, when the tensioner 74 is not operated, the pulley 20b does not drive the belt 72 and does not transmit the driving force to the pulley 80b. Thus, two sets of belt tension clutches are configured.

In the above configuration, the switching lever 5 and the tensioners 73 and 74 are interlocked, and the switching lever 5
Thus, only one of the tensioners 73 and 74 is operated. When the switching lever 5 is rotated to the forward position, the tensioner 73 operates and the pulley 80a is driven. The switching lever 5
Is rotated to the neutral position, the tensioner 7
3.74 does not operate and the pulleys 80a and 80b are not driven. When the switching lever 5 is turned to the reverse position, the tensioner 74 is operated, and the pulley 80b is driven.

The output shaft 11a rotates, and the pulley 20
a and 20b rotate in the same direction, and the tensioner 73 is operated by the switching lever 5 to apply tension to the belt 71.
When the tensioner 74 is actuated to apply tension to the belt 72, the pulley 80b is turned in the opposite direction to the pulley 20b.

For example, by operating the tensioner 73, the pulley 80a can be rotated forward with respect to the output shaft 11a, and by operating the tensioner 74,
The pulley 80b can be reversed with respect to the output shaft 11a. That is, by operating one of the tensioner 73 and the tensioner 74, the rotation direction of the input shaft 81 can be selected. Therefore, the driving direction input to the input shaft 81 can be changed without changing the turning direction of the output shaft 11a of the engine 11, and when turning while moving backward, the turning direction of the steering handle 14 is equal to the turning direction. Therefore, you can drive with the same feeling as a normal car.

Next, a second embodiment for transmitting a driving force to the input shaft 81 or 81b of the steering driving device 2 will be described. 3 and 4, the output shaft 11a of the engine 11 is shown.
A pulley 20a and a pulley 20b are inserted and fixed to the shaft. An electromagnetic clutch 8 is mounted in front of the pulley 20a and the pulley 20b on the input shaft 81 of the steering driving device 2.
A pulley 80a and a pulley 80b that are inserted through the 5.86 are provided. Belt 76 is pulley 2
0a and the pulley 80a in parallel, so that the driving force of the pulley 20a can be transmitted to the pulley 80a. An electromagnetic clutch 85 is mounted at the center of the pulley 80a, and the rotation of the pulley 80a can be transmitted to the input shaft 81 by the operation of the electromagnetic clutch 85.

The belt 77 is crossed around the pulley 20b and the pulley 80b. Guides 72a and 72b are in contact with the belt 77, and the guide 72a urges the belt above the intersecting belt 77 upward, and the guide 72b applies the belt below the intersecting belt downward. I'm going. Therefore, the belts 77 do not come into contact with each other. Thus, the driving force of the pulley 20b can be transmitted to the pulley 80b. An electromagnetic clutch 86 is mounted at the center of the pulley 80b.
Can be transmitted to the input shaft 81.

In the above configuration, the pulleys 80a and 80
The electromagnetic clutches 85 and 86 are linked to the switching lever 5, and the pulleys 80a and 8 are operated by the switching lever 5.
Only one of the electromagnetic clutches 85 and 86 is operable. An electromagnetic clutch corresponding to the position of the switching lever 5 is operated to transmit a driving force to the input shaft 81. When the switching lever 5 is at the neutral position, both the electromagnetic clutches 85 and 86 of the pulleys 80a and 80b are not operated.

Therefore, the output shaft 11a rotates, the pulleys 20a and 20b rotate in the same direction, and the electromagnetic clutch 85 of the pulley 80a is actuated to output the pulley 80a via the belt 76. Axis 11
can rotate in the same direction with respect to a. When the electromagnetic clutch 86 of the pulley 80b is operated,
The pulley 80b can be turned in the opposite direction to the output shaft 11a via the belt 77.

That is, the rotation direction of the input shaft 81 can be selected by operating the electromagnetic clutch 85 of the pulley 80a or the electromagnetic clutch 86 of the pulley 80b. Therefore, the driving direction input to the input shaft 81b can be changed without changing the turning direction of the output shaft 11a of the engine 11, and when turning while moving backward, the turning direction of the steering handle 14 is the same as the turning direction. Therefore, you can drive with the same feeling as a normal car.

Next, referring to FIG. 6 and FIG.
A third embodiment in which the driving force of the second driving force is transmitted to the steering driving device 2 will be described. In FIG. 6, a pulley 20c is fixedly inserted into an output shaft 11a of the engine 11, and one of the pulleys 20c is provided with a pump shaft 3 of the steering driving device 2.
A pulley 304 inserted into the pump shaft 321 via the electromagnetic clutch 303 is connected to the pump shaft 321 on the other side.
A pulley 306 inserted through the connector 5 is provided. The pulley 20c and the pulley 304
A belt 76 b is hung parallel to 306. Therefore,
The rotation of the output shaft 11a is rotated in the same direction by the pulleys 304 and 306.

By operating the electromagnetic clutch 303, the driving force from the engine 11 is transmitted to the pulley 30.
4 can be transmitted to the pump shaft 315, and the power can be transmitted from the pulley 306 to the pump shaft 321 by operating the electromagnetic clutch 305.

The electromagnetic clutches 303 and 305 are interlocked with the switching lever 5 so that one of the electromagnetic clutches 303 and 305 can be operated according to the turning position of the switching lever 5. When the switching lever 5 is rotated to the neutral position, neither of the electromagnetic clutches 303 and 305 is operated.

As shown in FIG. 7, a gear train is provided at the upper and lower central portions of the input shaft 315.
The gear 313 is inserted and fixed at the upper and lower central portions of the pump shaft 321, and is covered with a case 301 on the upper surface of the housing 25. The input shaft 315 and the pump shaft 321 in the case 301
The support shafts 312 and 314 are rotatably supported between them, and gears 311 and 313 are fixed on the support shafts 312 and 314, respectively. The gear 311 meshes with the 315b and the gear 313, and 313 further meshes with the gear 321b. Thus, the input shaft 315 and the pump shaft 321 are configured to rotate in directions opposite to each other.

In order to adopt the above configuration, the pulley 30
4 by operating the electromagnetic clutch 303 mounted on the input shaft 31 via the pulley 304.
5, the input shaft 315 is connected to the engine 1
1 is rotated in the same direction as the output shaft 11a.
The pump shaft 321 is rotated in the opposite direction to the input shaft 315 from the gear 315b inserted and fixed to the gear 5 through the gears 311, 313, and 321b.

When the electromagnetic clutch 305 mounted on the pulley 306 is operated and the driving force of the engine 11 is input to the pump shaft 321 via the pulley 306, the driving force is applied to the input shaft 315 via the gear train. The rotation in the opposite direction to the rotation of the output shaft 11a of the engine 11 is transmitted.

With the construction described above, the electromagnetic clutch 30 is rotated by the rotation of the forward / reverse lever 5 in forward running.
The HST 21 and 22 are driven by selecting and operating the HST 2 and the electromagnetic clutch 305 is operated and the HST 2
When the 1.22 hydraulic pumps are driven to rotate in the reverse direction, and the steering wheel 14 is turned when turning backward, the steering operation can be performed with the same feeling as the turning operation of the automobile.

In the above configuration, the steering drive 2
Although the configuration in which the direction of the driving force input to the vehicle is switched by the forward / reverse lever 5 is shown, the forward / backward travel is performed by using the shift pedal 15 provided on the body step instead of the forward / backward lever 5. It is also possible to correspond to the neutral position of the lever 5, to correspond to the forward position of the forward / reverse lever 5 when the forward pedal is depressed, and to correspond to the reverse position of the forward / reverse lever 5 when the reverse pedal is depressed. is there.

[0046]

According to the present invention, there are provided two sets of hydraulic pumps and hydraulic motors, and two differentials connected to respective output shafts, wherein the two sets of differentials are provided. And a gear drive is provided on each of the two HST pump shafts, the gear trains are interlockingly connected by a gear train, and an input shaft to the gear train is provided. And two pulleys are fixedly mounted on the output shaft of the prime mover, a belt is hung in parallel between one pulley, and the other belt is crossed to form two sets of belt transmission mechanisms. Since the transmission mechanism is provided with the forward rotation and reverse rotation clutches, the driving direction of the driving force input to the HST transmission can be changed with an easy configuration, and therefore, the driving force input to the HST transmission can be changed. The mechanism can be configured simply, It is possible to improve the resistance.
Further, since a drive change mechanism using a complicated gear for changing the driving force of the engine is not required, the drive mechanism of the HST transmission can be simply configured, and the space for disposing the drive mechanism is effectively reduced. Can be used. Further, the number of parts can be reduced, the manufacturing cost can be reduced, and the assemblability can be improved.

According to a second aspect of the present invention, a tensioner is disposed in each of the two sets of belt transmission mechanisms, and the clutch is configured as a belt tension type clutch so that the drive direction to the input shaft can be changed. With such a configuration, the driving direction of the driving force input to the HST transmission can be changed, and a drive change mechanism with a complicated gear for changing the driving force of the engine is not required.
The weight can be reduced.

According to a third aspect of the present invention, an electromagnetic clutch is interposed between two pulleys arranged on one of the input shaft and the output shaft of the prime mover, and one of the electromagnetic clutches is interposed between the two pulleys. The drive direction can be changed by actuating the clutch, so that the drive direction can be changed by switching the switch, the switch operation unit can be set to any position, and the interlocking connection with other forward / reverse levers etc. It can be done easily.

Further, as set forth in claim 4, two sets of HST,
Having two differentials connected to each output shaft,
This is a steering drive device in which the two sets of differentials are interlocked and the left and right axles can be driven in a variable speed. At the same time, a belt is wound between a pulley provided on both the pump shafts and a pulley provided on the output shaft of the motor, and an electromagnetic clutch is interposed between the pump shafts and the pulleys of the two HSTs, respectively. Since the driving direction of each HST to the input shaft can be changed by operating the electromagnetic clutch, the driving direction of the driving force input to the HST transmission can be changed with a simple configuration. The driving force input mechanism to the HST transmission can be simply configured, and the durability can be improved.

[Brief description of the drawings]

FIG. 1 is an overall side view of a mower employing a steering driving device.

FIG. 2 is a perspective view of a main part showing a configuration for transmitting a driving force from an engine.

FIG. 3 is a perspective view of a main part showing a second embodiment for transmitting a driving force from an engine.

FIG. 4 is a front sectional view of the HST.

FIG. 5 is a front sectional view of an HST which is another embodiment of the gear train.

FIG. 6 is a perspective view of a main part showing a third embodiment for transmitting a driving force from an engine.

FIG. 7 is a front sectional view of an HST according to a third embodiment.

FIG. 8 is a skeleton diagram showing a drive mechanism for a rear wheel.

FIG. 9 is a skeleton diagram showing a rear wheel drive mechanism according to a second embodiment.

[Explanation of symbols]

 5 Forward / reverse switching lever 11a Output shaft 20a / 20b Pulley 71/72 Belt 72a / 72b Guide 73/74 Tensioner 80a / 80b Pulley 81 Input shaft 111/112/113 Gear

 ──────────────────────────────────────────────────の Continued on the front page F-term (reference) JJ10 JJ21

Claims (4)

[Claims] 1. Two sets of a hydraulic pump and a hydraulic motor (hereinafter referred to as H
ST), and a steering drive device having two differential devices connected to the respective output shafts, and interlockingly connecting the two sets of differential devices so that the left and right axles can be shifted. A gear is provided on each of the pump shafts of the two HSTs, and the gear trains are interlocked with each other, and two pulleys are respectively fixed on the input shaft to the gear train and the output shaft of the prime mover, and a belt is provided between one of the pulleys. , And the other belt is cross-linked to form two sets of belt transmission mechanisms, and the two sets of belt transmission mechanisms are provided with forward and reverse clutches. Drive. 2. The clutch according to claim 1, wherein a tensioner is arranged in each of the two belt transmission mechanisms, and the clutch is configured as a belt tension type clutch so that a driving direction to an input shaft can be changed. Vehicle steering drive. 3. An electromagnetic clutch is interposed between two pulleys disposed on one of the input shaft and the output shaft of the prime mover, and a driving direction is established by operation of one of the electromagnetic clutches. 2. The steering driving device for a vehicle according to claim 1, wherein the driving force can be changed. 4. A vehicle comprising two sets of HSTs and two differentials connected to respective output shafts, wherein the two sets of differentials are interlocked and connected so that the left and right axles can be shifted. A steering drive device, wherein gears and pulleys are provided on pump shafts of two HSTs, respectively, and are interlockedly connected by gear trains. A pulley provided on both pump shafts and a pulley provided on an output shaft of a motor are provided. Between the pump shafts and the pulleys of the two HSTs, and each of the HSs is operated by the operation of the electromagnetic clutch.
A steering drive device for a vehicle, wherein a drive direction of an input shaft of T can be changed.