JPH09286345A - Steering control device for hst running device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive steering control for adopting a steering wheel which can be operated with an automobile driving feeling. SOLUTION: When a forward/reverse switching lever 112 is operated, the clutches of forward/reverse switching units 42R, 42L are set at a forward position or a reverse position. When a speed increasing/decreasing lever 152 is slanted to a speed increasing side, the operating force is transmitted to the clutch of the forward/reverse switching unit via speed increasing/decreasing link mechanisms 116R, 116L to rotate a shaft via the clutch, whereby the swash plates of the hydraulic pumps 36R, 36L are slanted and pump output is increased. When a steering wheel 132 is rotated, a pinion for rotation built in a rotation unit 118 is rotated via a chain 136 to pull one of the speed increasing/ decreasing link mechanisms 116R, 116L, whereby the output of the corresponding hydraulic pump is increased via the speed increasing/decreasing unit connected to the link is increased, which rotates a running device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for an HST traveling device in which the left and right traveling wheels can be independently rotated by hydraulic motors provided corresponding to the left and right traveling wheels, respectively. .

[0002]

2. Description of the Related Art Conventional steering control devices for agricultural tractors and the like have a structure as shown in FIG. This steering control device includes a right traveling crawler 10R and a left traveling crawler 1
0L, a right traveling motor 12R and a left traveling motor 10L are provided corresponding to these crawlers 10R, 10L, and each of the crawlers 10R, 10L can be independently driven to rotate, a so-called HST. It is a traveling device. Each of the traveling motors 12R and 12L is composed of a hydraulic motor, and a right pump 1 which is a variable displacement swash plate hydraulic pump via hydraulic circuits 14R and 14L.
6R and left pump 16L connected to these pumps 1
It is adapted to be driven by hydraulic oil discharged from 6R and 16L.

The right pump 16R and the left pump 16L are connected to the output shaft of the engine 18 and can be operated by the engine 18. Further, each hydraulic pump 16R, 16L is provided with pump levers 20R, 20L (not shown) for controlling the swash plate angle, and by controlling these pump levers 20R, 20L, switching between forward and backward travel of the traveling device is performed. , Speed adjustment, turning can be performed. And each pump lever 20
An operating lever 24R and a left operating lever 24L for operating the levers 20R and 20L are connected to the R and 20L via a shift cable 22.

In the traveling apparatus (vehicle) having such a structure, the operation levers 24R, 24L are set in the forward direction 2 of the vehicle.
By tilting to the 6 side, the swash plates of the pumps 16R and 16L can be tilted to the forward side and the crawlers 10R and 10L can be rotated in the vehicle forward direction, and the operation levers 24R and 24L can be moved to the vehicle rear side. By defeating
The swash plate is inclined toward the vehicle rearward direction so that the crawlers 10R and 10L can be rotated in the vehicle rearward direction. Then, for example, in the forward state of the vehicle, when the right operation lever 24R is set to the neutral position and the left operation lever 24L is tilted to the forward side, the right crawler 10R stops and the left crawler 1
The 0L rotates in the forward direction so that the vehicle turns rightward.

[0005]

By the way, when an attachment is mounted on the rear side of an agricultural tractor and traveling while checking the rear side, one-handed maneuvering is required, and at the same time, one that supports the upper body of the operator is required. And However, as described above, the pair of operation levers 24R, 24L
When performing steering control by operating the, the one-handed operation is difficult and the operability of the upper half of the operator is very poor.
Therefore, a steering control device for an HST traveling device has been developed which performs steering control by using a steering wheel like an ordinary automobile.

However, a conventional steering control device for an HST traveling device using a steering wheel is a hydraulic control for controlling the flow rate of hydraulic oil by using an electromagnetic hydraulic valve or the like, which makes the device expensive. However, it is currently used in high-priced large vehicles, but not in low-priced small vehicles. For this reason, it is desired to develop an inexpensive steering control device for an HST traveling device that enables steering control using a steering wheel as if it were an automobile.

The present invention has been made in view of the above demands, and an object of the present invention is to provide an inexpensive steering control device for an HST traveling device that can be operated by a steering wheel like an automobile.

[0008]

In order to achieve the above-mentioned object, a steering control device for an HST traveling device according to the present invention comprises:
Hydraulic motors provided corresponding to the left and right running wheels and rotating the left and right running wheels independently of each other in the forward and reverse directions, and provided in correspondence with these hydraulic motors and driving the corresponding hydraulic motors in the forward and reverse directions. A swash plate type hydraulic pump, a forward-reverse switching gear that is provided corresponding to each of these hydraulic pumps, and that rotates forward and backward to incline the corresponding swash plate of the hydraulic motor to the forward or reverse side, and each of these forward and backward movements. A forward-reverse switching rack that is provided corresponding to the forward-reverse switching gear and rotates the forward-reverse switching gear in the forward or reverse direction, and an engaging member that is detachably attached to the forward-reverse switching rack and is disengageable from the rack. A forward / reverse switching lever that is connected to each of the engaging members, and the engaging members are moved to rotate the forward / reverse switching gear via the forward / reverse switching rack to change the inclination angle of the swash plate. The deceleration operating mechanism meshes with the turning rack with which the acceleration / deceleration operating mechanism is engaged, rotates in conjunction with the rotation of the steering wheel, and moves the turning rack to move the above-mentioned each via the acceleration / deceleration operating mechanism. And a slewing gear that moves the engagement member corresponding to one of the hydraulic motors.

[0009]

According to the present invention constructed as described above, the steering control can be performed by rotating the steering wheel. When the vehicle is traveling while checking the rear side by attaching the attachment to the rear side like an agricultural tractor. In addition, one-handed operation is possible, and the upper half of the body can be supported by the steering wheel, so that the driver can drive like a normal automobile. Moreover, since the steering control is performed via the turning pinion and the turning rack that are rotated by the steering wheel, the turning operation is performed reliably, the device can be made compact, and expensive electromagnetic hydraulic valves and the like can be used. Since it is not necessary, the device can be made inexpensive,
It can be easily adopted in a small traveling device. Further, the forward / reverse switching and acceleration / deceleration of the traveling device are performed by changing the inclination angle of the swash plate of the hydraulic pump by the forward / reverse switching gear and the forward / reverse switching rack, so that the correct forward / backward switching and speed can be achieved. The device can be controlled and the device can be made compact.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a steering control device for an HST traveling device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic structural explanatory diagram of a steering control device for an HST traveling device according to an embodiment of the present invention. In FIG. 1, a right traveling crawler 30R and a left traveling crawler 30L that form a lower traveling body of an HST traveling device (vehicle) are wound around left and right idler wheels 32R and 32L that are traveling wheels and a drive wheel (not shown). It's spinning. The right drive wheel and the left drive wheel are the right hydraulic motor 34R provided corresponding to each other.
And the left hydraulic motor 34L, which are independently rotated by these hydraulic motors 34R and 34L in forward and reverse directions, so that the HST traveling device can move forward, backward, or turn left and right. You can do it. The hydraulic motors 34R and 34L are connected to the corresponding swash plate type variable displacement hydraulic pumps 36R and 36L via hydraulic circuits 38R and 38L. These hydraulic pumps 36R, 36L can adjust the output (the amount of hydraulic oil discharged) by the inclination angle of a swash plate (not shown), and change the inclination of the swash plate between the forward drive side and the reverse drive side to allow the hydraulic motor 34R, At 34L, it is rotationally driven in the forward direction to move the traveling body forward or in the reverse direction to move the traveling body backward.

Each of the hydraulic pumps 36R and 36L is connected to the output shaft of the engine 40 and driven by the engine 40. And Engine 4
The rotation speed of 0 is adjusted by a throttle lever (not shown). By adjusting the throttle lever and changing the rotation speed of the engine, the rotation speeds of the hydraulic motors 36R and 36L are changed to change the hydraulic oil. The discharge amount (output) can be changed. Further, in the right hydraulic pump 36R and the left hydraulic pump 36L, a shaft (not shown) for changing the angle of the swash plate is provided in each hydraulic pump 36R,
Forward / reverse switching unit 42R provided corresponding to 36L,
42L and these switching units 42
The inclination angle of the swash plate can be controlled by R and 42L. Then, these forward / reverse switching unit 42
R and 42L have the same structure.

As shown in FIG. 2, each forward / reverse switching unit 42 has a gear box 44, and a switching pinion 46, which is a forward / reverse switching gear, is arranged in the gear box 44. And the switching pinion 46
Is fixed to a shaft 48 which is rotatably supported by passing through the gear box 44. This shaft 48 is connected to the hydraulic pump 36.
The shaft for changing the inclination angle of the swash plate is interlocked to rotate, and as will be described later in detail, the output of the pump 36 can be changed by rotating the switching pinion 46, and the hydraulic motor 34 can be rotated forward and backward. ing. Also, the gear box 4
In the upper and lower parts of FIG. 2 in FIG. 4, there are provided a forward rack 50 and a reverse rack 52, which are forward and backward switching racks arranged in parallel and opposite to each other.

These racks 50 and 52 have rack teeth 54 formed on one end side in the longitudinal direction of the facing surfaces, and the rack teeth 54 mesh with the switching pinion 46. Further, rollers 56 are interposed between the racks 50 and 52 and the top plate or bottom plate of the gear box 44,
The racks 50 and 52 are movable relative to the top plate and the bottom plate. By moving the racks 50 and 52 to the left in FIG. 2 along the inner surface of the top plate or the bottom plate, the switching pinion 46 is rotated and the swash plate is moved. You can change the corners.
That is, when each of the racks 50 and 52 is in the position shown in FIG. 2, the swash plate is in the neutral position where it is not inclined,
The output of the hydraulic pump 36 becomes zero. Then, when the forward rack 50 moves to the left in FIG. 2, the switching pinion 46
Rotates in the counterclockwise direction (forward direction) in FIG. 2 as indicated by arrow 58, and the swash plate is inclined toward the forward position. When the reverse rack 52 moves to the left in FIG. 2, the switching pinion 46 rotates in the clockwise direction (reverse direction) in FIG. 2 as indicated by arrow 60, and the swash plate is inclined toward the reverse position. .

The forward rack 50 and the reverse rack 52 have saw tooth-shaped engaging teeth 62 formed on the facing surfaces on the other end side opposite to the side where the rack teeth 54 are provided. A clutch 68 as an engaging means is arranged between the engaging teeth 62. The clutch 68 has a guide block 70, and a pair of sliding holes 72, 7 are provided in the guide block 70.
4 is formed in parallel with the vertical direction of the drawing, and a forward engaging pin 76 and a reverse engaging pin 78 are arranged in these sliding holes 72, 74. In addition, each sliding hole 72, 74
Are stepped holes each having a small diameter portion and a large diameter portion, and the formation positions of the small diameter portion and the large diameter portion are upside down.

That is, the sliding hole 72 in which the forward engaging pin 76 is arranged has a small diameter portion in the upper portion of the drawing and a large diameter portion in the lower portion of the drawing, and the other of the sliding holes 72 in which the backward engaging pin 78 is disposed. The sliding hole 74 has a large diameter portion at the upper portion of the drawing and a small diameter portion at the lower portion of the drawing. The engaging pins 76 and 78 arranged in the sliding holes 72 and 74 have a head at one end located inside the large diameter portion of the sliding holes 72 and 74, and slide with the head. Hole 72,
A return spring 80, the operation of which will be described later, is interposed between the stepped portion 74 and the step portion. Further, each of the engagement pins 76, 78 is provided with a serrated engagement tooth 82 at the other end located on the small diameter portion side of the sliding holes 72, 74. These engaging teeth 82 are opposite in tooth orientation to the engaging teeth 62 formed on the forward rack 50 and the backward rack 52, and engage with the engaging teeth 62 on the rack side.

Further, the large diameter portions of the sliding holes 72, 74 in which the head portions of the engaging pins 76, 78 are arranged have a pressing pin 84,
86 is disposed across the sliding holes 72, 74. The pressing pins 84 and 86 penetrate the gear box 44 and can move in the vertical direction along a long hole (not shown) formed in the gear box 44. The heads of 78 are pressed to engage the engaging pins 76, 78
Is moved in the axial direction, and the engagement teeth 82 of the engagement pin are moved to the rack 5
It is possible to engage with the engaging teeth 62 formed in 0 and 52. The pressing pins 84 and 86 penetrating the gear box 44 are provided on the side plate 8 of the U-shaped pin bracket 88 which is arranged so as to straddle the gear box 44 from above.
9, both ends are supported. The pin bracket 88 can prevent the forward engagement pin 84 from moving downward when it moves downward, and prevents the reverse engagement pin 86 from moving upward when it moves upward. A long hole that can be formed is formed (neither is shown). The pin bracket 88 is supported by an L-shaped clutch lever 90 and can be moved up and down by the clutch lever 90.

The L-shaped clutch lever 90 has a bent portion provided with a pin 9 on a bracket 92 provided on the upper portion of the gear box 44.
3, a holder 96 is rotatably attached downward to the lower end of one end side arm portion 94 extending in the lateral direction, and a pin bracket is attached to the lower end of the holder 96. Support bolt 9 penetrating the top plate portion 100 of 88
8 is projected. A spring seat is screwed to the lower end of the support bolt 98. Support springs 102 and 104 having support bolts 98 penetrating are interposed between the upper surface of the spring seat and the lower surface of the top plate portion 100 and between the upper surface of the top plate portion 100 and the lower end of the holder 96. The support brackets 102 and 104 can support the pin bracket 88 in the neutral position.

In the clutch lever 90, a link 108 is connected to the upper end of the other end side arm portion 106 extending upward, and as described later, the forward / backward movement switching lever is moved to the forward position,
When the link 108 is set to the reverse position,
The clutch lever 90 in the direction of arrow 11
The engaging pin 76 can be engaged with the forward rack 50 and the engaging pin 78 can be engaged with the reverse rack 52 by swinging like 0 and moving the pin bracket 88 up and down. Then, when the forward / reverse switching lever is returned to the neutral position, the engagement pins 76, 78 are engaged with the sliding holes 82,
The return spring 80 arranged on the large diameter portion 84 of the rack 5
The engagement with 0 and 52 is released.

Note that, as shown in FIG. 1, the clutch lever 90 of the right forward / reverse switching unit 42R and the clutch lever 90 of the left forward / reverse switching unit 42L are connected by a link 108. And this link 1
Reference numeral 08 denotes a part of a switching link mechanism 114 that transmits the operating force of the forward / reverse switching lever 112, and the forward / reverse switching unit 4 is operated by operating the forward / reverse switching lever 112.
The 2R and 42L are designed to work together. Further, the engagement block 7 is provided on the guide block 70 of the clutch 68.
Forward rack 50 or reverse rack 52 via 6, 78
2 to the left in FIG. 2 to rotate the switching pinion 46 counterclockwise or clockwise.
Are provided (see FIG. 2). This pull rod 115 is shown in FIG.
As shown in FIG. 7, the turning unit 118 is connected via the acceleration / deceleration link mechanisms 116R and 116L that constitute the acceleration / deceleration operation mechanism.
Connected to

The turning unit 118 has a turning pinion 122 at the center of the gear box 120, as shown in FIG. This pinion 122
Is rotatably attached to a swing shaft 124 that penetrates the gear box 120 in the vertical direction. A rack guide 128 for guiding the turning racks 126L and 126R arranged along the other pair of inner surfaces is fixed to the pair of inner surfaces (the inner surface in the vertical direction of FIG. 3) facing each other of the gear box 120. There is. Further, as will be described later in detail, the swing shaft 124 has one end swingably attached to the vehicle body side so that the swing unit 118 can be tilted in a plane orthogonal to the plane of the drawing.

That is, the swing shaft 124 is swingable in a plane which is orthogonal to the paper surface of FIG. 3 and parallel to the left-right direction of FIG. 3. By swinging the swing shaft 124, The swivel unit 118 can be swung as indicated by an arrow 130. And the pinion 122 is
A pair of racks 126R and 126L arranged on the left and right of FIG.
1 and is rotated about the swing shaft 124 by the steering wheel 132 shown in FIG. 1 to move the racks 126R and 126L in the vertical direction of FIG.

That is, a sprocket 134 having a swing shaft 124 penetrating is coaxially coupled to the turning pinion 122, and a chain 136 wound around the sprocket 134 is fixed to a steering shaft 138 of a steering wheel 132. It is wound around the sprockets 140. Therefore, when an operator (not shown) rotates the steering wheel 132, the rotation is transmitted to the turning pinion 122 via the steering shaft 138, the sprocket 140, the chain 136, and the sprocket 134, and the pinion 122 moves in the same direction as the steering wheel 132. Rotate.

A swing rack 126 of the swing unit 118.
R and 126L have rectangular turning control grooves 142R and 142L on the inner surface side of the gear box 120, respectively.
It is formed in the longitudinal direction of 26L. Rectangular (or square) claws 144R and 144L, which match the groove width, are fitted into the turning control grooves 142R and 142L. Then, on the back surface of these claws 144R, 144L, there is provided a shaft 148 which is projected to the outside of the gearbox 120 through an elongated hole 146 formed in the gearbox 120,
Forward / reverse switching units 42R, 4
The other ends of acceleration / deceleration link mechanisms 116R and 116L each having one end connected to a 2 L pull rod 115 are fixed.

At one end of the swing shaft 124 penetrating the gear box 120, the acceleration / deceleration lever 1 which constitutes an acceleration / deceleration operation mechanism is connected via a link and a shift cable 150.
52 is connected to the shift cable 1 by tilting the acceleration / deceleration lever 152 to the acceleration side.
50 by inclining the swing shaft 124 and inclining the swing unit 118 integrally with the swing shaft 124,
The links of the acceleration / deceleration link mechanisms 116R and 116L are inclined toward the front of the paper surface of FIG. 3 so that the pull rod 115 shown in FIG. 2 can be pulled leftward in FIG.

That is, as shown in FIG. 4, the swing shaft 124 has a bracket 162 whose other end is fixed to the vehicle body 160.
A link 166 is pivotally attached to the shaft via a pin 164, and a link 166 is connected to one end thereof via a connecting member 168 via the operation force of the acceleration / deceleration lever 152 being transmitted. The pinion 122 through which the swing shaft 124 penetrates is the bracket 1
The hub portion provided on the 62 side is exposed to the outside of the gear box 120, and the wheel bracket 17 for attaching the sprocket 134 to the hub portion via the joint 170.
2 is fixed.

The wheel bracket 172 is mounted on the swing shaft 12
4, and the turning pinion 122 is rotated integrally with the sprocket 134. The wheel bracket 172 has a recess 174 formed in the central portion on the upper surface side, and the sprocket 134 is fixed to the end surface of the ring-shaped mounting portion 176 at the peripheral edge portion. The sprocket 134 is formed in a ring shape having a through hole 173 in the center, and can be inserted into the recess 174 of the wheel bracket 172 by penetrating the tip of the bracket 162 to which the swing shaft 124 is pivotally attached. Is done. The vehicle body 160 is provided with a stopper 178 that guides the swing of the turning unit 118 and regulates the maximum swing angle.

An accelerating / decelerating pedal 156, which is a part of an accelerating / decelerating operating mechanism, is attached to the swing shaft 124 via a link 154.
2 is connected, the swing shaft 124 is tilted by depressing the acceleration / deceleration pedal 156, and the pull rod 115 is moved to the position shown in FIG.
It can be pulled to the left of. The acceleration / deceleration lever 152 and the acceleration / deceleration pedal 156 are configured to automatically return to their initial positions by a spring or the like (not shown) when the operating force is released.

The operation of the embodiment configured as described above is as follows. When advancing the traveling device, first, the forward / reverse switching lever 112 is moved to the forward position. As a result, the operating force of the forward / reverse switching lever 112 is applied to the forward / reverse switching units 42R and 42L via the switching link mechanism 114 (link 108).
2, the clutch lever 90 rotates in the clockwise direction in FIG. 2 about the pin 93, and the pin bracket 88 supported by the tip end of the arm 94 via the support springs 102 and 104 is pulled upward. . When the pin bracket 88 rises, the pressing pin 84 arranged across the sliding hole 72 rises together with the pin bracket 88, and the forward engaging pin 76.
Are pushed up to engage the engaging teeth 82 with the engaging teeth 62 formed on the forward rack 50. At this time, the other backward engaging pin 86 is prevented from moving upward by the elongated hole formed in the pin bracket 88.

When the forward / rearward engagement pin 76 is engaged with the forward rack 50, when the acceleration / deceleration lever 152 is tilted to the acceleration side (or the acceleration / deceleration pedal 156 is depressed), the operating force is applied via the link 166. Is transmitted to the swing shaft 124 penetrating the gear box 120 of the swing unit 118, and the swing shaft 124 tilts the swing unit 118.
Then, due to the tilt of the turning unit 118, the acceleration / deceleration link mechanisms 116R and 116L are tilted toward the front side of the paper surface of FIG. 2, and the pull bar 115 of the forward / reverse switching unit 42 connected to the acceleration / deceleration link mechanisms 116R and 116L is illustrated. 2, the forward rack 50 engaged with the forward engaging pin 76 moves leftward in FIG. Therefore, the switching pinion 46 meshing with the rack teeth 54 of the forward rack 50 rotates counterclockwise in FIG. 2 and rotates the shaft 48 in the same direction to tilt the swash plates of the hydraulic pumps 36R and 36L to the forward side. Let Thereby, the hydraulic motors 34R, 34L
Rotates forward to rotate the traveling crawlers 30R, 30L in the forward direction. When changing the forward speed, the inclination amount of the acceleration / deceleration lever 152 (or the depression amount of the acceleration / deceleration pedal 156) is changed to change the inclination angle of the swash plate, or the rotational speed of the engine 40 is changed by a throttle lever (not shown). Do by changing.

When the forward / reverse switching lever 112 is returned to the neutral position, the clutch lever 90 is rotated counterclockwise in FIG. 2 via the switching link mechanism 114 and returned to the neutral position.
The pin bracket 88 is pushed down by the spring force of the support spring 104, and is held in the neutral position by the spring force of the support springs 102 and 104. Then, the forward engaging pin 76
Is moved to the head side (lower side in FIG. 2) by the return spring 80 arranged in the large diameter portion of the sliding hole 72, and the forward rack 5
The engagement with 0 is released. When the forward rack 50 is disengaged from the clutch 68, the forward rack 50 is returned to the initial position by a return mechanism (not shown), and the switching pinion 46 is rotated clockwise to bring the shaft 48 into the neutral position. As a result, the surfaces of the swash plates of the hydraulic pumps 36R and 36L are orthogonal to the axis, the discharge of hydraulic oil is stopped, and the driving of the hydraulic motors 34R and 34L is stopped.

When the vehicle is moved in reverse, the forward / reverse switching lever 112 is moved to the reverse position so that the clutch lever 90 rotates counterclockwise in FIG. 2 and pushes down the pin bracket 88 to move the reverse engagement pin. The engaging teeth 82 of 78 are engaged with the engaging teeth 62 of the reverse rack 52. At this time, the forward engaging pin 76 is prevented from moving downward by the elongated hole provided in the pin bracket 88. When the acceleration / deceleration lever 152 is tilted to the acceleration side, the pull bar 115 moves leftward in FIG. 2 to move the reverse rack 52 in the same direction as described above, and the switching pinion 46 rotates clockwise. Then, the swash plate is tilted backward.

When the vehicle is turned, for example, when the forward vehicle is turned to the right, the steering wheel 132 is rotated clockwise (to the right). When the steering wheel 132 is rotated clockwise, the rotation causes the steering shaft 138 and the sprocket 14 to rotate.
0, the chain 136, and the sprocket 134 are transmitted to the turning pinion 122 of the turning unit 118 to rotate the pinion 122 clockwise in FIG. Therefore, the turning rack 12 meshing with the pinion 122
6L is the inner surface of the gear box 120 and the rack guide 128
While being guided by and moving upward in FIG. 3, the other turning rack 126R moves downward in FIG. Then, the claw 142 fitted in the turning control groove 142L of the left rack 126L moves upward together with the rack 126L, and further pulls the pull rod 115 of the left forward / reverse switching unit 42L via the acceleration / deceleration link mechanism 116L. , The switching pinion 46 is further rotated counterclockwise via the forward rack 50 to tilt the swash plate. As a result, the output of the left hydraulic pump 36L becomes larger than that of the right hydraulic pump 36, and the rotation speed of the left hydraulic motor 34L is increased.
4 becomes higher than the rotation speed and the vehicle turns right.

When the vehicle moving backward is turned to the right, it can be performed in the same manner as described above by rotating the steering wheel 132 to the right. Further, for example, when turning to the right on the forward side, the forward / reverse switching lever 112 is set to the forward position and the clutch 68 is moved.
Engage with the forward rack 50. And the acceleration / deceleration lever 1
The steering wheel 132 is rotated to the right without operating 52 and the acceleration / deceleration pedal 156. As a result, as described above, the forward rack 50 of the left hydraulic forward / reverse switching unit 42L is moved by the acceleration / deceleration link mechanism 116L.
Moves leftward in FIG. 2 to rotate the switching pinion 46 counterclockwise, and the left hydraulic pump 36L operates to drive the left hydraulic motor 34L. However, since the forward rack 50 on the right hydraulic pump 36R side does not move, the right hydraulic pump 36R does not move.
There is no R output, and the right hydraulic motor 34R does not rotate. For this reason, only the left traveling crawler 30L rotates in the forward direction, and the turning to the right is performed. When making a turning turn to the left, it can be performed in the same manner as described above by positioning the forward / reverse switching lever 112 on the reverse side and rotating the steering wheel 132 to the left.

As described above, in the embodiment, the steering control of the traveling device can be performed by rotating the steering wheel 132, and the acceleration / deceleration pedal 15 can be used.
Since the traveling device can be accelerated or decelerated by the stepping amount of 6, it becomes possible to drive like a normal automobile, and when traveling while checking the rear with an attachment attached to the rear like an agricultural tractor. One-handed operation is possible, the upper half of the body can be supported by the steering wheel 132, and the operation can be performed easily.
Moreover, the steering control is performed by the turning pinion 122 and the turning racks 126R and 126L.
Since it is a mechanical type that controls the angle of the swash plate of L, the turning operation can be reliably performed, the device can be made compact, and an expensive electromagnetic hydraulic valve etc. is not required, so an inexpensive steering is possible. The device can be realized and can be adopted in a small traveling device.

Further, in the embodiment, the forward / reverse switching is performed by engaging the clutch 68 interlocking with the forward / reverse switching lever 112 with the forward rack 50 or the reverse rack 52 of the forward / reverse switching unit 42. Therefore, it is possible to accurately switch between forward and reverse. Then, the output control of the hydraulic motors 36R and 36L for acceleration / deceleration is controlled by the switching pinion 46 provided in the forward / backward switching units 42R and 42L.
Since it is rotated by 2, the output control can be performed easily and reliably, and the device can be downsized.

[0037]

As described above, according to the present invention, the steering control can be performed by rotating the steering wheel, and like the agricultural tractor, the attachment is attached to the rear side and the rear side is attached. When traveling while checking, one-handed operation can be performed, and the upper half of the body can be supported by the steering wheel, so that the driver can drive like a normal automobile. Moreover, since the steering control is performed via the turning pinion and the turning rack that are rotated by the steering wheel, the turning operation is performed reliably, the device can be made compact, and expensive electromagnetic hydraulic valves and the like can be used. Since it is not necessary, the device can be made inexpensive and can be easily adopted in a small traveling device. Further, the forward / reverse switching and acceleration / deceleration of the traveling device are performed by changing the inclination angle of the swash plate of the hydraulic pump by the forward / reverse switching gear and the forward / reverse switching rack, so that the correct forward / backward switching and speed can be achieved. The device can be controlled and the device can be made compact.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory diagram of a steering control device for an HST traveling device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing details of a forward / reverse switching unit according to the embodiment.

FIG. 3 is a detailed cross-sectional view of a turning unit according to the embodiment.

FIG. 4 is a cross-sectional view showing a mounted state of the swing shaft according to the embodiment.

FIG. 5 is an explanatory diagram of a conventional steering control device for an HST traveling device.

[Explanation of symbols]

30L Left traveling crawler 30R Right traveling crawler 32L, 32R Running wheels (left idle wheel, right idle wheel) 34L Left hydraulic motor 34R Right hydraulic motor 36L Left hydraulic pump 36R Right hydraulic pump 42L, 42R Forward / reverse switching unit 46 Forward / reverse switching gear (Switching pinion) 48 Shaft 50, 52 Forward / backward switching rack (forward rack, backward rack) 68 Engaging member (clutch) 64, 66 Operating portion 76, 78 Engaging pin 112 Forward / backward switching lever 116L, 116R Acceleration / deceleration operating mechanism (Acceleration / deceleration link mechanism) 118 swivel unit 122 swivel gear (spinning pinion) 124 swing shaft 126L, 126R swivel rack 136 chain 144L, 144R pawl 152, 156 acceleration / deceleration operation mechanism (acceleration / deceleration lever, acceleration / deceleration pedal)

Claims (1)

[Claims] 1. A hydraulic motor which is provided corresponding to the left and right running wheels and which rotates the left and right running wheels independently of each other in forward and reverse directions, and a hydraulic motor which is provided corresponding to these hydraulic motors. A swash plate type hydraulic pump that drives forward and reverse, and a forward-reverse switching gear that is provided corresponding to each of these hydraulic pumps and that tilts the swash plate of the corresponding hydraulic motor by forward and reverse rotation to the forward side or the reverse side. A forward / reverse switching rack for rotating the forward / reverse switching gears in a forward direction or a reverse direction, and an engaging member detachably attached to the forward / reverse switching racks. A forward / reverse switching lever that engages / disengages with a rack, and the engaging member is moved to rotate the forward / reverse switching gear via the forward / reverse switching rack, and the swash plate of the swash plate is connected. The acceleration / deceleration operation mechanism for changing the bevel angle is meshed with the turning rack with which the acceleration / deceleration operation mechanism is engaged, and it rotates in conjunction with the rotation of the steering wheel to move the turning rack to move the acceleration / deceleration operation mechanism. A steering control device for an HST traveling device, comprising: a swivel gear that moves the engagement member corresponding to one of the hydraulic motors via a rotary gear.