JPH08142897A - Driving device for hydraulic drive vehicle - Google Patents

Abstract

PURPOSE: To enable stable turning travel without the generation of a slip by regulating the rotating speed of dirigible road wheels according to a steering angle, and driving the right and left dirigible road wheels at the rotating speed corresponding to the difference of moving distance of the right and left dirigible road wheels generated in association with turning travel. CONSTITUTION: In a hydraulic drive vehicle 1 with driving wheels 4 (4L, 4R)-6 (6L, 6R) disposed on both lateral sides in the front and rear of a body, hydraulic motors 33L, 33R for driving one of right and left side wheels among driving wheels 4-6 are provided, and the driving wheels 4-6 on the same side are connected to the output shafts 36 of the respective hydraulic motors 33L, 33R through interlocking mechanism 37. It is so constituted that the rotating speed of the output shafts 36 of the respective hydraulic motors 33L, 33R can be continuously regulated, and the hydraulic motors 33L, 33R to be on the inside of the turn in association with the operation of a steering wheel control in such a way that the rotating speed of the output shafts 36 is lower than the rotating speed of the hydraulic motors 33L, 33R to be on the outside by the part corresponding to the steering angle of the dirigible road wheels 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a hydraulically driven vehicle.

[0002]

2. Description of the Related Art In a hydraulically driven vehicle, the rotational speeds of hydraulic motors for driving the left and right wheels are controlled separately by operating independent speed control levers for the left and right wheels without rolling the left and right wheels. The skid steering system is generally adopted in which the wheels are turned to change the direction.

In a hydraulically driven vehicle, since the left and right wheels are driven by separate hydraulic motors, no special differential mechanism is installed between the left and right wheels.

[0004]

Such a conventional hydraulically driven vehicle is required to have a driving operation different from that of an ordinary passenger vehicle, and when the operability of the hydraulically driven vehicle is taken into consideration,
It is considered preferable to give a steering wheel a turning angle by manipulating a steering wheel like a normal passenger car so that steering can be performed.

However, the hydraulic drive type vehicle does not have a special differential mechanism because of the above circumstances.
When a steering mechanism is added to a conventional hydraulically driven vehicle that simply gives the steering wheel a turning angle by operating the steering wheel, when turning, the turning trajectory due to the turning angle of the steering wheel and the left and right wheels And the wheel speed difference between the left and right wheels does not match the rotational speed of either the left or right wheel (mainly the inner wheel side), and the slip ratio of that wheel with respect to the road surface becomes large Not enough force and lateral force can be obtained, which hinders stable turning.

Further, in this type of hydraulically driven vehicle in which a plurality of drive wheels are arranged on both the left and right sides of the vehicle body in the front-rear direction of the vehicle, the turning is performed even between the drive wheels arranged on the same side. Since there is no match between the length of the trajectory and the rotational speeds of the drive wheels arranged in the front and rear, the slip ratio of the wheels becomes large and the stability of turning traveling is impaired.

The present invention has been made under such circumstances, and it is an object of the present invention to enable stable turning traveling in a hydraulically driven vehicle of this type with little risk of slipping.

[0008]

In order to achieve this object, a first aspect of the present invention is to dispose a plurality of drive wheels on both left and right sides of a vehicle body in the front-rear direction of the vehicle so as to be spaced apart from each other. In a hydraulically driven vehicle in which at least a left and right pair is steered by operating a steering handle, a hydraulic motor for driving the drive wheels corresponding to one of the left and right sides of the vehicle body among the drive wheels. Therefore, the hydraulic motors that drive the left and right parts are installed separately, and the multiple drive wheels that are spaced apart in the front-rear direction on the same side of the vehicle body All driving wheels are driven by connecting and supplying pressure oil from the pressure oil source to each of the hydraulic motors, and the rotation speed of the output shaft of each of the hydraulic motors can be continuously adjusted to control the steering. Rotate with the operation of the handle It characterized in that to minimize the rotation speed of the output shaft of the inner become side of the hydraulic motor according to the steering angle of the steering wheel than the rotational speed of the outer side of the hydraulic motor min.

According to a second aspect of the present invention, in the hydraulically driven vehicle drive device according to the first aspect, the hydraulic motor installed corresponding to the left and right drive wheels of the vehicle body has a pressure oil source. A hydraulic pump is installed corresponding to each hydraulic motor, and the pressure oil from each hydraulic pump is exclusively supplied to the corresponding hydraulic motor.

According to a third aspect of the present invention, in the drive system for the hydraulically driven vehicle according to the first or second aspect,
A flow control valve is installed in each of the hydraulic lines from the pressure oil source to each of the hydraulic motors, and the opening of the flow control valve is adjusted according to the turning angle of the steering wheel to adjust the steering wheel. It is characterized in that the rotational speed of the output shaft of the hydraulic motor on the inner side of the turn is reduced by an amount corresponding to the turning angle of the steered wheels as compared with the rotational speed of the hydraulic motor on the outer side in accordance with the operation.

According to a fourth aspect of the present invention, in the drive system for a hydraulically driven vehicle according to the third aspect, each hydraulic line extending from the pressure oil source to each hydraulic motor is connected to each hydraulic line. It is characterized in that a switching valve capable of reversing connection is installed, and each switching valve installed in each hydraulic line allows only one switching valve to be in a reversing connection state.

[0012]

According to the first aspect of the present invention, since the rotational speed of the steered wheels is adjusted according to the turning angle by the steering of the steered wheels, the left and right steered wheels are moved during turning. The left and right steered wheels are driven at the rotational speed according to the difference in the distance, so that the driving force and the lateral force can be reliably maintained without the risk of slippage.

In this case, the drive wheels other than the steered wheels also cause the vehicle body to turn by producing the same speed difference between the left and right drive wheels in response to the turning travel, and the steered wheels on the same side. There is no risk of slippage because there is no differential speed between the two.

Therefore, there is little risk of slippage,
It is possible to provide a hydraulically driven vehicle that can perform stable turning travel.

According to the second aspect of the present invention, since the hydraulic pumps are installed corresponding to the respective hydraulic motors and the pressure oil from the respective hydraulic pumps is supplied to the corresponding hydraulic motors for driving, When the wheel on one side gets stuck in muddy, there is no pressure drop of the hydraulic motor on the other side, it is avoided that the driving force of the wheel on the other side is reduced, and the running performance on bad roads is good. .

According to the third aspect of the invention, since the rotational speed of the hydraulic motor is adjusted by using the flow control valve, the rotational speed of the hydraulic motor is controlled with a relatively simple structure. be able to.

Further, according to the invention as set forth in claim 4, a switching valve capable of reversing connection of each hydraulic line is installed in each hydraulic line leading to each hydraulic motor, and one of these switching valves is provided. Since only the switching valve is allowed to be in the reverse connection state, by setting only one switching valve in the reverse connection state, the driving directions of the left and right wheels can be opposite to each other. By driving the left and right wheels at a constant speed, the vehicle can perform a pivot movement.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. First, an outline of a steering device 2 of a hydraulically driven vehicle (hereinafter, simply referred to as a vehicle) 1 will be described with reference to FIG. The drive device 3 will be described with reference to FIG.

In FIG. 2, reference numeral 1 denotes a vehicle, which is indicated by an arrow F.
Indicates the front of the vehicle, 4 is a front wheel as a steering wheel, 5 is an intermediate wheel, 6 is a rear wheel, and these are also drive wheels as described later. In the front wheels 4, the intermediate wheels 5, and the rear wheels 6, the suffix R indicates the right wheel, and the suffix L indicates the left wheel.

The front wheel 4, the intermediate wheel 5 and the rear wheel 6 are arranged on both left and right sides of the vehicle 1, and the intermediate wheel 5 is installed at a central position between the front wheel 4 and the rear wheel 6.

Among the front wheels 4, the intermediate wheels 5 and the rear wheels 6, the front wheels 4 and the rear wheels 6 are mounted around the kingpins 11 of the respective wheels via steering devices 7, 8 for the front wheels or the rear wheels. The cutting angle is set so that it can be adjusted appropriately, but in the intermediate wheel 5, the intermediate wheel 5 is fixed in the front-rear direction, and the cutting angle cannot be adjusted.

The front wheel steering device 7 includes a steering shaft 12 rotatably installed and a bell crank 13 fixed to the steering shaft 12.

The knuckle arms 14 of the left and right front wheels 4L and 4R are connected to the bell crank 13 via a tie rod 15 composed of a hydraulic cylinder, and a steering hydraulic cylinder 16 is connected to the bell crank 13. Has been done.

Therefore, the bell crank 13 is displaced around the steering shaft 12 by expanding / contracting the steering hydraulic cylinder 16 in accordance with the operation of a steering handle (not shown), and the left and right front wheels 4L, 4R. The steering displacement can be performed around the kingpin 11 via the tie rod 15.

Further, in the front wheel steering device 7,
The cutting angles of the left and right front wheels 4L, 4R can also be adjusted by expanding and contracting the hydraulic cylinders constituting the tie rods 15.

For example, with the bell crank 13 in the neutral position, the cutting angles of the left and right front wheels 4L, 4R are set to 0, and in this state, the tie rods 15 connected to the left and right front wheels 4L, 4R are equal in length. When the vehicle 1 is reduced, it can be formed into a “C” shape as shown by an imaginary line A in FIG. 2, and the vehicle 1 can be pivotally moved around the center point O as described later.

In the steering device 7 for the front wheels, a concentric disc member 17 is fixed around the steering shaft 12, and an outer cable 2 is formed of an inner cable of Bowden wire. Book wire 2
Connect one end of each of 1 and 22 to these wires 2
The other ends of 1 and 22 are connected to the operation portion of a flow rate control valve 34, which will be described later.

On the other hand, the rear wheel steering device 8 is substantially the same as the front wheel steering device 7 described above, except that the components corresponding to the disc member 17 and the wires 21, 22 are not installed. Be different.

Therefore, in the following description, the same parts as those of the front wheel steering system 7 are designated by the same reference numerals, and a duplicate description will be omitted.

Also in this rear wheel steering device 8, the bell crank 13 is moved to the steering shaft 12 by expanding and contracting the steering hydraulic cylinder 16 in response to the operation of the rear wheel steering handle (not shown). The left and right rear wheels 6L and 6R can be displaced around the kingpin 11 via the tie rods 15 (see phantom line B in FIG. 2).

Also in the rear wheel steering device 8,
The cutting angles of the left and right rear wheels 6L and 6R can also be adjusted by expanding and contracting the hydraulic cylinders that form the tie rods 15. As with the left and right front wheels 4L and 4R, the phantom line A in FIG. It is also possible to have a "C" shape as shown.

The drive device 3 of the vehicle 1 equipped with such a steering device 2 is constructed as follows (FIG. 1).
reference).

That is, the drive device 3 of the vehicle 1 has an engine 31 as a drive source and a hydraulic pump device 32 which is driven by being connected to the output shaft of the engine 31.

The hydraulic pump device 32 comprises a double hydraulic pump and corresponds to a pressure oil source in the present invention, and one of the double hydraulic pumps is a left wheel hydraulic pump 32L. , The other is the right wheel hydraulic pump 32R
Is.

The left wheel hydraulic pump 32L and the right wheel hydraulic pump 32R are operated at a constant speed by the output shaft of the engine 31, and both are variable displacement hydraulic pumps.

Then, these left wheel hydraulic pumps 3
The pressure oil generated by 2L and the hydraulic pump 32R for the right wheel passes through the flow control valve 34 and the switching valve 35, respectively, independently of each other and exclusively for the left wheel driving hydraulic motor 3 respectively.
It is adapted to be supplied to a 3L or a right wheel driving hydraulic motor 33R.

In this embodiment, the pressure oil source is constituted by separate hydraulic pumps independently on the left and right sides as described above, for example, when one wheel on one side of the vehicle 1 gets stuck in a muddy state. The reason is that a large amount of pressure oil is supplied to the hydraulic motor on one side, the hydraulic pressure is reduced, and the driving force of the wheels on the other side is prevented from being reduced, so that the running performance on a rough road is maintained in good condition.

In this embodiment, the flow control valve 34 has four
It consists of a port 3 position type pressure compensation type variable flow control valve,
The flow rate can be continuously adjusted manually, and the other end of the wire 21 or 22 is connected to the operator portion.

That is, in the flow rate control valve 34 installed in the hydraulic line from the left wheel hydraulic pump 32L, the other end of the wire 21 is attached to the operator portion thereof, and the hydraulic pressure from the right wheel hydraulic pump 32R is applied. The other end of the wire 22 is connected to the operator portion of the flow rate control valve 34 installed in the pipeline.

Therefore, in these flow rate control valves 34, the manipulator portion of the one installed in the hydraulic line to the wheel on the inside of the turning side of the vehicle 1 by the rotational displacement of the steering shaft 12 is the wire 21 or. 22 is operated by the flow rate control valve 34, and the flow rate of the pressure oil supplied to the hydraulic motor that drives the wheel on the inside of the turn is reduced by that amount according to the turning angle of the front wheel 4 that is the steering wheel. As a result, the rotational speed of the left wheel drive hydraulic motor 33L or the right wheel drive hydraulic motor 33R is correspondingly reduced.

At this time, since the flow rate control valve 34 is a pressure compensation type flow rate control valve, a constant torque can be maintained even if the rotational speeds of the left and right wheel drive hydraulic motors 33L and 33R decrease. Since the driving force of the driving wheels is maintained, the vehicle can travel stably.

In this embodiment, the flow control valve 34 is used because the hydraulic circuit configuration and the flow control method thereof can be made relatively simple.

The switching valve 35 to which the pressure oil reaches via the flow rate control valve 34 is a 4-port 3-position electromagnetic switching valve, and in normal operation, the hydraulic system of the left wheel hydraulic pump 32L and the right wheel. Both the switching valves 34 of the hydraulic system of the hydraulic pump 32R are set to the left position to move the vehicle 1 forward and backward.

However, in this embodiment, the hydraulic system of the left wheel hydraulic pump 32L and the right wheel hydraulic pump 32L are used.
Both switching valves 34 of the R hydraulic system are designed so that the switching operation can be performed independently of each other.

Therefore, the vehicle 1 is rotated around the center point O as shown in FIG.
In the case of pivoting along a circular locus indicated by an imaginary line C, the left wheel driving hydraulic motor 33L and the right wheel driving hydraulic motor 33R are rotated in opposite directions. By driving at a high speed, the hydraulic system switching valve 34 of the left wheel hydraulic pump 32L is set to, for example, the left position, and the hydraulic system switching valve 34 of the right wheel hydraulic pump 32R is set to, for example, the right position so as to be different from each other. It can be carried out.

As described above, in this embodiment, the switching valve 35 which is separate from the flow control valve 34 is used, but a flow control valve 34 having the function of the switching valve 35 is used. It goes without saying that it is good.

The pressure oil passing through the switching valve 34 reaches the left wheel driving hydraulic motor 33L or the right wheel driving hydraulic motor 33R and drives them.

These drive hydraulic motors 33L, 33R
The respective output shafts 36 are connected to the front wheels 4L or 4R, the intermediate wheels 5L or 5R, and the rear wheels 6 via the reduction gear 36a and the interlocking mechanism 37 including a chain and a sprocket.
Since they are connected to L or 6R, they will be driven.

The left wheel drive hydraulic motor 33 is used.
The front wheel 4L, the intermediate wheel 5L, and the rear wheel 6 by the L output shaft 36.
The drive speed of L is set so that the peripheral speed of each wheel is constant, and the output shaft 36 of the hydraulic motor 33R for driving the right wheel is driven.
Driving of the right wheels 4R, 5R, 6R is also performed so that the peripheral speeds are constant, as described above.

In such a vehicle 1, when the steering handle is operated and the vehicle turns, the rotational speed of the steering wheel is adjusted in accordance with the steering angle of the steering wheel. , The steering wheel is driven at a rotational speed according to the difference in the moving distance between the left and right steered wheels caused by turning, and the steered wheel reliably maintains the driving force and lateral force without causing the risk of slipping. be able to.

In that case, since the other driving wheels are also driven at the rotational speed according to the moving distance, there is no risk of slip between the left and right driving wheels, and the steering is performed on the same side of the vehicle 1. Since there is no difference in speed between the wheels in the front-rear direction, such as with the wheels, there is no risk of slippage, and stable turning travel is possible.

[0052]

As described above, according to the first aspect of the invention, the rotational speed of the steered wheels is adjusted according to the turning angle by the steering of the steered wheels. The left and right steered wheels are driven at a rotational speed according to the difference in the generated travel distances of the left and right steered wheels, and the driving force and the lateral force can be reliably maintained without the risk of slippage.

In this case, the drive wheels other than the steered wheels also cause the vehicle body to turn by causing a similar speed difference between the left and right drive wheels in response to the turning traveling, and the steered wheels on the same side. There is no risk of slippage because there is no differential speed between the two.

Therefore, there is little risk of slippage,
It is possible to provide a hydraulically driven vehicle that can perform stable turning travel.

According to the second aspect of the invention, since the hydraulic pumps are installed corresponding to the respective hydraulic motors and the pressure oil from the respective hydraulic pumps is supplied to the corresponding hydraulic motors to be driven, When one side wheel gets stuck in muddy water, it is avoided that a large amount of pressure oil is supplied to the one side hydraulic motor and the hydraulic pressure drops, and the driving force of the other side wheel is reduced. The running performance is good.

According to the third aspect of the invention, since the rotational speed of the hydraulic motor is adjusted by using the flow rate control valve, the rotational speed of the hydraulic motor is controlled with a relatively simple structure. be able to.

Further, according to the invention described in claim 4, a switching valve capable of reversing connection of each hydraulic pipeline is installed in each hydraulic pipeline leading to each hydraulic motor, and one of these switching valves is provided. Since only the switching valve is allowed to be in the reverse connection state, by setting only one switching valve in the reverse connection state, the driving directions of the left and right wheels can be opposite to each other. By driving the left and right wheels at a constant speed, the vehicle can perform a pivot movement.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a steering device for a hydraulically driven vehicle.

FIG. 2 is an explanatory diagram of a drive device of a hydraulically driven vehicle.

[Explanation of symbols]

 1 Hydraulically driven vehicle 4, 4L, 4R Front wheel (steering wheel) 5, 5L, 5R Intermediate wheel 6, 6L, 6R Rear wheel 32 Hydraulic pump device (pressure oil source) 32L Left wheel hydraulic pump 32R Right wheel hydraulic Pump 33L Left wheel hydraulic motor 33R Right wheel hydraulic motor 34 Flow control valve 35 Switching valve 36 Output shaft 37 Interlocking mechanism

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Matsuura 2109 Yashima Nishimachi, Takamatsu City, Kagawa 8 Shikoku Research Institute Co., Ltd. (72) Inventor Atsushi Yamashita 51-128 Fukunocho, Matsuyama City, Ehime Prefecture (72) Inventor 52-30, Ryuo, Aibatake, Ishii-cho, Meisai-gun, Tokushima Prefecture

Claims (4)

[Claims] 1. A hydraulic system in which a plurality of drive wheels are arranged on both left and right sides of a vehicle body in the front-rear direction of the vehicle so as to be spaced apart from each other, and at least a pair of left and right of these drive wheels is steered by operating a steering handle. In a drive-type vehicle, hydraulic motors for driving one of the drive wheels corresponding to one of the left and right sides of the vehicle body are separately installed. A plurality of drive wheels spaced apart in the front-rear direction are mechanically connected to the output shaft of the hydraulic motor on the corresponding side via an interlocking mechanism, and pressure oil from a pressure oil source is supplied to each hydraulic motor. All driving wheels are driven, the rotation speed of the output shaft of each hydraulic motor can be continuously adjusted, and the rotation of the output shaft of the hydraulic motor on the inner side of turning is accompanied by the operation of the steering handle. Speed on the outside Hydraulically driven vehicle driving apparatus characterized by reduced by an amount corresponding to the rotation speed of the pressure motor turning angle of the steering wheel. 2. The drive device for a hydraulically driven vehicle according to claim 1, wherein the hydraulic motors installed corresponding to the left and right drive wheels of the vehicle body respectively correspond to the hydraulic motors as pressure oil sources. A drive device for a hydraulically driven vehicle characterized in that a hydraulic pump is installed, and pressure oil from each hydraulic pump is exclusively supplied to a corresponding hydraulic motor. 3. A drive system for a hydraulically driven vehicle according to claim 1 or 2, wherein a flow control valve is installed in each of hydraulic lines from a pressure oil source to each of the hydraulic motors. By adjusting the opening according to the turning angle of the steering wheel, the rotation speed of the output shaft of the hydraulic motor on the inner side of the turn is rotated by the operation of the steering wheel. A drive device for a hydraulically driven vehicle, which is smaller than a speed by an amount corresponding to a turning angle of a steering wheel. 4. A drive device for a hydraulically driven vehicle according to claim 3, wherein a switching valve capable of reversing connection of each hydraulic pipeline is provided in each hydraulic pipeline from a pressure oil source to each hydraulic motor. However, the drive device of the hydraulically driven vehicle is characterized in that each of the switching valves installed in the respective hydraulic lines is allowed to have only one switching valve in a reverse connection state.