JPH1095242A - Drive mechanism for crawler type traveling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive without stopping a travel device at the time of low speed travel and turning so as to travel stably. SOLUTION: Crawler type travel devices are arranged on both lateral sides of a traveling vehicle, and the crawler type travel devices are driven by a lateral pair of two-pump two-motor type HST transmission. The HST transmission is composed of a variable displacement hydraulic pump P and a variable displacement hydraulic motor M, and control levers 50, 70 for rotating a movable cam plate of the hydraulic pump P and a movable cam plate of the hydraulic motor M are interlockingly connected so that the capacity of the hydraulic motor M is increased at the time of rotating the movable cam plate of the hydraulic pump P onto the low speed side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to drive a traveling vehicle using a two-pump two-motor type HST transmission,
Also, the present invention relates to a technique for enabling a steering operation.

[0002]

2. Description of the Related Art Conventionally, a working vehicle such as a combine, a tractor or a construction machine is equipped with an HST type transmission, and a crawler type traveling device is driven by left and right hydraulic motors. The discharge amount of each of the hydraulic pumps on the left and right sides of the HST transmission is controlled by steering the steering wheel and the forward / backward traveling lever in conjunction with each other to steer and drive the left and right crawler traveling devices. It is known. The hydraulic pump and the hydraulic motor are connected by a closed circuit, and the output rotation speed of the hydraulic motor is increased by changing the angle of the movable swash plate of the hydraulic pump and increasing the discharge amount from the hydraulic pump. I was

[0003]

However, in a case where the working machine is towed at a low speed in a fragile field when the work machine is towed, if the steering wheel is operated to turn to one of the two, the hydraulic pump from the turning-side hydraulic pump is turned on. Since the discharge amount is reduced, the suction amount of the hydraulic motor is reduced, and the torque is reduced. As a result, the traction force is significantly reduced, and the crawler inside the turn stops. Although the outer crawler is driven, it sometimes sinks in weak land and cannot travel.

[0004]

The problem to be solved by the present invention is as described above. Next, in order to solve the problem, crawler-type traveling devices are arranged on both left and right sides of a traveling vehicle. In a configuration in which the traveling device is driven by a pair of left and right two-pump two-motor HST transmissions, the HST transmission is constituted by a variable displacement hydraulic pump and a hydraulic motor, and a movable swash plate of the hydraulic pump is provided. And the control levers for rotating the movable swash plate of the hydraulic motor are linked to each other so that the capacity of the hydraulic motor increases when the movable swash plate of the hydraulic pump is rotated to the low speed side.

[0005]

Next, an embodiment of the present invention will be described. 1 is an overall side view of a crawler tractor having a crawler type traveling device, FIG. 2 is an overall plan view of the same crawler tractor, and FIG. 3 is a plan view showing a connection state between a variable displacement hydraulic pump and a hydraulic motor according to the present invention. FIG. 4 is a plan view showing another embodiment.

Referring to FIG. 1, a crawler tractor to which the crawler type traveling device of the present invention is applied will be described.
First, the overall configuration of the crawler tractor will be described. The fuselage frame 15 is fixed on the crawler type traveling device S, a bonnet 24 containing the engine E is provided in front of the fuselage frame 15, and an operating unit 16 is provided at a rear portion thereof. The steering handle 5, the driver's seat 22 and the like are arranged, and a rotary tilling device B is mounted on a rear portion of the operating unit 16 via a work implement mounting device A.

The crawler type traveling device S includes a track frame 12 for supporting a pair of right and left crawlers,
.., A driven sprocket 14, and a driving sprocket 3 for driving a crawler. The rolling wheels 11, 11 ...
Constitutes an equalizer and is rotatably supported on a shaft, and rotatably supports a driven sprocket 14 at the rear end of the track frame 12. As shown in FIG. 3, a hydraulic motor M is fixed to a front portion of the track frame 12, and a driving sprocket 3 driven by the hydraulic motor M is supported. These drive sprocket 3 and upper rolling wheel 1
3. The crawler belt 2 is wound around the rotating wheels 11, 11,...

As shown in FIG. 2, a front transmission case 20 is fixedly provided at the rear of the engine E. A pair of variable displacement hydraulic pumps PP are provided at the rear of the front transmission case 20. Has been arranged. The hydraulic pumps P · P and the left and right hydraulic motors M · M communicate with each other by pipes to form a closed circuit, an HST-type transmission, and hydraulic oil is supplied from the hydraulic pumps P · P to the hydraulic motors M · M. And drive it.

A front column 9 is provided at the rear of the hood 2 in the driving section 16, and a driver's seat 22 is disposed behind the front column 9. A steering handle 5 and a forward / reverse lever 30 protrude from the upper surface of the front column 9. Have been. In addition, a steering case 40 is arranged below the driving unit 16. The steering case 40 includes a forward / reverse lever 30.
And the operation of the steering wheel 5 is transmitted to the steering case 4
The control levers 50 of the hydraulic pumps P of the HST type transmission are rotated via the control lever 0. The control levers 50, 50 are linked with the movable swash plates of the hydraulic pumps P, P, and change the discharge amount of the pressure oil by rotating the control levers 50, 50.

Further, the output torque of the hydraulic motor M of the HST type transmission is proportional to the amount of hydraulic oil sucked by the hydraulic motor M. Therefore, in the present invention, the hydraulic motor The output torque is adjusted by interlocking the suction amount of the hydraulic motors MM with the hydraulic pumps PP. That is, as shown in FIG. 3, a control lever 70 protrudes from the variable displacement type hydraulic motor M. The control lever 70 is connected to a movable swash plate inside the hydraulic motor M, and is turned when it is rotated. The configuration is such that the suction amount of pressure oil can be changed. The control lever 70
Is rotated leftward on the paper surface, the suction amount of the hydraulic motor M is increased, and the output torque is increased.

When a link mechanism is used to link the control lever 70 of the hydraulic motor M and the control lever 50 of the hydraulic pump P in an interlocking manner, as shown in FIG. , A reciprocating link 71 that reciprocates left and right on the paper surface is pivotally supported, and the other end of the reciprocating link 71 is connected to the hydraulic pump P.
Of the control lever 50.

Accordingly, when the control lever 50 is turned to the uppermost forward angle position 50 'on the paper surface, the discharge amount of the hydraulic pump P to the forward side becomes maximum, and the hydraulic motor M is moved to the maximum forward position. Drives at speed and goes straight. When turning, the control lever 50 of one of the left and right hydraulic pumps P is moved to the forward maximum angular position 5.
When the hydraulic pump M is turned to the neutral side from 0 ′, the discharge amount of the hydraulic pump P is reduced, and the rotation speed of the hydraulic motor M is also reduced. The link 71 is moved, the control lever 71 is turned to the right on the paper surface, and the rotation of the movable swash plate of the hydraulic motor M increases the suction amount of hydraulic pressure to increase the output torque. Further, when the control lever 50 is rotated downward to rotate in the direction of the maximum backward angle 50 ", the hydraulic motor M is rotated in the reverse direction, and the crawler type traveling device S rotates backward and reciprocates. The link 71 is moved to the left.

The interlocking mechanism of the control levers 50 and 70 between the hydraulic pump P and the hydraulic motor M can be configured as shown in FIG. That is, an angle sensor 60 including a potentiometer, a rotary encoder, and the like is arranged on the central axis of the control lever 50 on the hydraulic pump P side, and the rotation angle of the control lever 50 is detected and input to the controller C. A rod of an actuator 61 such as a hydraulic cylinder or an electric cylinder is connected to an end of the control lever 70. The actuator 61 is connected to the controller C. And control lever 5
When the turning angle of 0 is turned to any position on the basis of the neutral position, the actuator 61 is adjusted in accordance with the turning angle.
Is contracted to control the amount of rotation of the control lever 70. In this case, the controller C not only performs proportional control like a link mechanism, but also changes the expansion start position, expansion amount, expansion amount and expansion speed of the actuator 61, or changes according to the speed by simply changing the program. You can also.

With this configuration, when the vehicle is turned at low speed, the angle of the movable swash plate of the hydraulic pump P on the turning side is changed, the discharge amount is reduced, and the hydraulic motor M on this side is rotated. The movable swash plate is also modified to increase the pressure oil suction. Therefore, the output torque of the hydraulic motor M is increased despite the deceleration, and the crawler inside the turning is driven without stopping. Further, when the steering handle 5 is rotated, the oil feeding direction from the hydraulic pump P is changed, the hydraulic motor M rotates in the reverse direction, the crawler-type traveling device S is driven to rotate in the reverse direction, and the body turns around the ground.

[0015]

As described above, the present invention has the following advantages. That is, even if the movable swash plate of the hydraulic pump P is rotated to the low speed side to reduce the discharge amount of the hydraulic pressure from the hydraulic pump P, the movable swash plate of the hydraulic motor is rotated to the side that increases the suction amount of the hydraulic pressure. Therefore, the output torque increases even if the number of rotations decreases, so that the traveling device can be driven without stopping during low-speed traveling or turning, and stable traveling can be performed. The work performance in a soft ground or the like where a heavy load is applied can be improved.

[Brief description of the drawings]

FIG. 1 is an overall side view of a crawler tractor having a crawler type traveling device.

FIG. 2 is an overall plan view of the crawler tractor.

FIG. 3 is a plan view showing a connection state between a variable displacement hydraulic pump and a hydraulic motor according to the present invention.

FIG. 4 is a plan view showing another embodiment.

[Explanation of symbols]

 S Crawler type traveling device P Hydraulic pump M Hydraulic motor 50 Control lever 70 Control lever

Claims (1)

[Claims] 1. A crawler-type traveling device is disposed on both left and right sides of a traveling vehicle.
In a configuration in which the HST-type transmission is driven by a two-motor pump-type HST-type transmission, the HST-type transmission is configured by a variable displacement hydraulic pump and a hydraulic motor, and a movable swash plate of the hydraulic pump and a movable swash plate of the hydraulic motor are formed. A drive mechanism for a crawler-type traveling vehicle, wherein each of the rotating control levers is interlocked so as to increase the capacity of the hydraulic motor when the movable swash plate of the hydraulic pump is rotated to the low speed side. .