JPH0532174A - Oil-hydraulic steering device of clawler vehicle - Google Patents

Abstract

PURPOSE:To facilitate steering operation even though a vehicle is embodied in a large size by maintaining the maneuvering force and the strokes so that they remain the same as conventional. CONSTITUTION:Steering of a clawler vehicle is made by operating a steering clutch and brake actuation pistons 3, 4 with an oil pressure fed from an coil pressure source under control made by a pressure proportioned control valve 2, which is configured in a single piece with an operational lever 1. Between the control valve 2 and steering clutch and brake actuation pistons 3, 4, a selector valve 5 for pressure conversion is installed which is to apply the oil pressure of the source from the switched oil path to the steering clutch and brake actuation pistons 3, 4. Thereby the control valve in a single piece with the operational lever shall not necessarily be enlarged even though enlarging the vehicle size causes a larger volume of a chamber in which the steering clutch and brake pistons are allowed to work. Thus operation can be done with a small maneuvering force and short strokes to ensure that the steering motions are generated easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic steering system for a tracked vehicle, and more particularly to a hydraulic steering system for a tracked vehicle suitable for a large vehicle.

[0002]

2. Description of the Related Art Conventionally, hydraulic steering devices for tracked vehicles have been
A mechanism was provided to control the torque capacity of the clutch / brake by adjusting the hydraulic pressure to the clutch actuating piston and the brake actuating piston, and thereby adjust the speed of the left and right crawler tracks via the left and right final reduction gears. There is something. That is, as shown in FIG. 4, an operation lever-2 provided with an operation valve for adjusting the operating oil pressure from the oil pressure source 21 in the cockpit (not shown)
The pressure proportional control valve 23 is integrally formed with the pressure control valve 23, and the clutch actuating piston 24 and the brake actuating piston 25 are actuated by a small operating force and a stroke to perform left and right steering. Are known. 26 in the figure
Is a friction plate, and 27 is a spring.

[0003]

However, when this system is applied to a larger vehicle, a large amount of oil passes through the pressure proportional control valve during operation because the working piston of the clutch and the brake becomes large. In order to prevent a time delay, the pressure proportional control valve must be made larger, and if it is made large, the operating force and stroke of the operating lever become large, making it difficult to operate. there were.

In view of this, the present invention provides a hydraulic steering device for a tracked vehicle in which, even if the vehicle becomes large, the operating force and the stroke at the time of steering operation are as small as those in the conventional case. The purpose of the invention is to eliminate the drawbacks of the prior art.

[0005]

SUMMARY OF THE INVENTION As a means for solving the above-mentioned problems of the prior art, the present invention is directed to right and left steering of a tracked vehicle,
In a steering device, which is operated by operating a pressure proportional control valve integrally formed with an operation lever by a hydraulic pressure from a hydraulic pressure source, disengaging a steering clutch on one side and entering a steering brake, An oil passage is switched to each side between the pressure proportional control valve and the steering clutch and the brake actuating piston by the control of the pressure proportional control valve, and the oil pressure of the hydraulic source is changed from the switched oil passage to the steering clutch. And a pressure conversion switching valve for operating the brake operating piston are provided respectively, and the switching valve is provided with a clutch release valve and a brake release valve.
It is equipped with a valve.

[0006]

According to the above construction, the switching valve for pressure conversion is switched by the control pressure of the pressure proportional control valve, and the oil pressure of the hydraulic source is changed through the switched oil passage.
Since it will operate on the operating piston, the operation lever
Control of the pressure proportional control valve by means of a large operating force or
The large steering clutch and the brake actuating piston can be easily actuated without the need for a crank.

[0007]

1 is a sectional view of an embodiment showing the right side of the structure of a hydraulic steering system for a tracked vehicle according to the present invention, and the left side is omitted because it is symmetrical with the right side.

According to the present invention, the left-right steering of a tracked vehicle (not shown) is integrated with the operation lever-1 so that the pressure proportional control valve 2 is integrated.
In the steering device which is operated by disengaging the steering clutch on one side and operating the steering brake with the hydraulic pressure from the hydraulic source, the pressure proportional control valve 2, the steering clutch and the brake are controlled. The oil passage is switched to each side between the working pistons 3 and 4 by the control of the pressure proportional control valve 2, and the oil pressure of the hydraulic source is supplied from the switched oil passage to the steering clutch and the brake working piston 3, 4. Pressure conversion switching valve 5,
5 are provided respectively, and the switching valve 5 is provided with a clutch release spool valve 7 and a brake release spool valve 8 (hereinafter abbreviated as spool valves 7 and 8). ..

The switching valve 5 includes a valve body 6 and spool valves 7 and 8.
The spool valves 7 and 8 are respectively fitted in valve holes 6a and 6b provided in the valve body 6 and are slidable in the longitudinal direction. Each of the spool valves 7 and 8 has a groove 7a, 7a, 8a, 8a which serves as an oil passage between the central portion and both end portions.
Are respectively provided in the circumferential direction. On the other hand, the valve body 6 also has valve holes 6a, 6b at three positions in the longitudinal direction at appropriate intervals.
Deeper annular passages 6a1, 6a2, 6a3, 6b1
, 6b2, 6b3 are provided concentrically, of which the passages 6a1 and 6b1, 6a3 and 6b3 on both sides are connected, one passage 6a3 is connected to the P port on the hydraulic pressure source side, and the other passage 6a1 is It is connected to the T port on the tank side. The central passages 6a2 and 6b2 are connected to the clutch operating piston 3 and the brake operating piston 4 respectively. Further, the valve body 6 facing the one side end faces A2, A4 of the spool valves 7, 8 is partially opened so that hydraulic pressure is supplied, and the other side end faces A1, A3 are the valve body 6 described above. It has been closed by. Further, each spool valve 7, 8 is provided with an L-shaped passage 9, 10 which passes through the inside from the other end surface A1, A3 and reaches the peripheral surface of the central portion. Circuits 11 and 12 are connected to the one end surfaces A2 and A4 via the openings so that the clutch hydraulic pressure and the brake hydraulic pressure from the pressure proportional control valve 2 act respectively. The operation of the operation lever-1 is shown in FIG.
As shown in FIG. 5, the clutch C is first operated to disengage the clutch, and then the clutch C is further pressed (to the brake B) to apply the brake. In the neutral position with respect to the valve body 6, the spool valves 7 and 8 are provided with passages 6a1 and 6a2, 6a2 and 6a3, 6b1 and 6a2.
, 6b2 and 6b3 are set to a position that prevents communication between them. In FIG. 1, 13 is a friction plate and 14 is a spring.

Next, the operation will be described. In order to turn right from the neutral position in FIG. 1 to disengage the clutch on the right side, tilt the operation lever-1 as shown in FIG. 2, and press C of the operation pattern in FIG. The proportional control valve 2 is actuated, and an oil pressure corresponding to the inclination from a hydraulic power source (not shown) first acts on the right end surface A2 of the spool valve 7 to cause the spool valve 7 to move.
To the left side of the figure. As a result, P
The oil in the passage 6a3 after passing through the passage flows to the clutch operating piston 3 side when the passages 6a2 and 6a3 communicating with the clutch operating piston 3 communicate with each other, so that the hydraulic pressure on the operating piston 3 side rises. At the same time, this hydraulic pressure is guided to the A1 side via the oil passage 9 leading to the left end surface A1 of the relay valve 7 and pushes back the spool valve 7, so that the passages 6a2 and 6a are formed.
When communication with 3 is closed and the pressure of the clutch operating piston 3 becomes A2 / A1 of the pressure of the pressure proportional control valve 2, the pressure increase of the clutch operating piston 3 stops in balance.

When the pressure of the pressure proportional control valve 2 is reduced, the pushing-back force of the spool valve 7 from the left end face A1 is reduced by the right end face A1.
Passing the pushing force of No. 2, the spool valve 7 moves to the left again and the passage 6a2 and the passage 6a1 on the T port side, which is the tank side.
, And the hydraulic pressure on the side of the clutch piston 3 decreases, and decreases to a balanced state as described above. Figure 3
See (a) and (c). As a result, the pressure on the side of the clutch actuating piston 3 becomes a hydraulic pressure corresponding to the pressure of the pressure proportional control valve 2, and at the same time, the size of the spool valve 7 is made large enough to handle the passing flow rate. The problem with is solved.

After disengaging the clutch as described above,
To apply the key, push the operation lever-1 into the operation pattern B of FIG. 2 to guide the pressure of the pressure proportional control valve 2 to the right end face A4 of the spool valve 8 as in the case of the clutch, and to -The valve 8 is pushed to the left in FIG.
Passage 6b2 through the port to the brake actuating piston 4
And 6b3 are communicated with each other, the hydraulic pressure applied to the brake piston 4 rises and a brake is applied. Then, just as in the case of the clutch, when the hydraulic pressure of the brake actuating piston 4 is guided from the passage 10 to the left end surface A3, the spool valve 8 is pushed back to the right, and the pressure of the pressure proportional control valve 2 x (A4 / A
In the case of 3), a balanced state is established and the pressure increase of the brake piston 4 stops. Hereafter, the operation is the same as in the case of the clutch. See Figures 3 (b) and (d). As a result, the vehicle turns right because the steering device on the right side stops.

In the above description, in the case of the illustrated clutch brake on the right side, the friction plate 13 is disengaged from the clutch by hydraulic pressure against the spring 14 and the friction plate 13 is disconnected from the brake. However, it goes without saying that the left clutch and brake (not shown) can be operated in the same manner as the right clutch.If the left clutch is disengaged and the brake is engaged, the vehicle will rotate to the left. It will be turned.

[0014]

As described above, according to the present invention, the lateral steering of a tracked vehicle is steered to one side by the hydraulic pressure from the hydraulic source by the control of the pressure proportional control valve which is integrally formed with the operating lever. In a steering device which is operated by disengaging a clutch and operating a steering brake, the pressure proportional control valve is provided on each side between the pressure proportional control valve and a steering clutch and a brake operating piston. The oil passages are switched under the control of the above-mentioned control, and pressure conversion switching valves for operating the hydraulic pressure of the hydraulic pressure source from the switched oil passages to the steering clutch and the brake operating piston are provided respectively, and the switching valves are provided with a clutch release brake. Since the vehicle is equipped with a valve and a brake release valve, even if the volume of the chamber for operating the steering clutch and the piston of the brake increases due to the increase in size of the vehicle, pressure proportional control integrated with the operating lever is performed. The valve becomes larger It is not necessary, therefore small operating force and short stroke - will be able to operate in a click,
Easy steering operation.

[Brief description of drawings]

FIG. 1 is an explanatory view of a cross section on the right side with the left side omitted, showing an embodiment of a hydraulic steering device for a tracked vehicle according to the present invention.

FIG. 2 is an explanatory view of an operation pattern of the operation lever of FIG. 1 viewed from above.

FIG. 3 is a graph showing a control range of hydraulic pressure of a pressure proportional control valve and a clutch / brake of a hydraulic steering system for a tracked vehicle according to the present invention.

FIG. 4 is an explanatory diagram of a conventional hydraulic steering device for a tracked vehicle.

[Explanation of symbols]

 1 Operation lever 2 Pressure proportional control valve 3 Clutch actuating piston 4 Brake actuating piston 5 Switching valve 6 Valve body 7 Clutch release spool valve 8 Breaker release spool valve

Claims (1)

Claim: What is claimed is: 1. A steering clutch on one side is disengaged by hydraulic pressure from a hydraulic pressure source for controlling left and right steering of a tracked vehicle by controlling a pressure proportional control valve which is integrally formed with an operating lever. In a steering device which is operated by entering a steering brake, the pressure proportional control valve is controlled on each side between the pressure proportional control valve and a steering clutch and a brake operating piston. A pressure conversion switching valve for switching the oil passage and operating the hydraulic pressure of the hydraulic source from the switched oil passage to the steering clutch and the brake operating piston is provided, and the switching valve has a clutch relay.
A hydraulic steering device for a tracked vehicle comprising a spool valve and a break-relay spool valve.