WO1994005915A1

WO1994005915A1 - Hydraulic braking system

Info

Publication number: WO1994005915A1
Application number: PCT/JP1993/001253
Authority: WO
Inventors: Mitsuru Arai; Mitsuru Oshiro
Original assignee: Kabushiki Kaisha Komatsu Seisakusho
Priority date: 1992-09-04
Filing date: 1993-09-03
Publication date: 1994-03-17
Also published as: JPH0681806A

Abstract

A braking system of a hydraulic motor, wherein the hydraulic motor and a control valve are allowed to communicate with each other through first and second main circuits, a check valve and a counterbalance valve are provided in the first and the second main circuits, portions of the first and the second main circuits, which are disposed closer to the hydraulic motor than to the check valve, are allowed to communicate with each other through a short-circuit path having a two-way operating safety valve, a set pressure at the safety valve is raised by pressure supplied to the spring chamber of the safety valve, and the spring chamber is connected to the counterbalance valve through a path, whereby, in said path, there is provided a slow return valve for allowing the fluid to flow slowly to the spring chamber and also allowing the fluid to smoothly flow out of the spring chamber. As the result, when the control valve is switched to supply the fluid discharged from a hydraulic pump into the first or the second main circuit, the fluid discharged from the hydraulic pump slowly acts on the spring chamber of the safety valve to gradually raise a set pressure, so that such disadvantages can be avoided that, during the reverse operation of the control valve, shocks occur or a high peak pressure is generated at the time of the stop of the hydraulic motor in operation.

Description

Specification

Fluid brake device

Technical field

The present invention relates to a fluid brake device that restricts the flow of high-pressure fluid discharged from a fluid motor when the fluid motor performs a pump action, and applies a brake to the fluid motor.

Conventional technology

2. Description of the Related Art A fluid brake device disclosed in Japanese Utility Model Laid-Open Publication No. 60-38901 is known.

That is, as shown in FIG. 1, a check valve 5 and a counter balance valve 6 are provided in the first and second main circuits 3 and 4 for connecting the fluid motor 1 and the operation valve 2. When the hydraulic motor 1 is stopped with the operation valve 2 in the neutral position N, the counterbalance valve 6 is set in the shut-off position to restrict the flow of the high-pressure fluid discharged from the hydraulic motor 1 and apply the dynamic brake to the hydraulic motor 1. Let it. The portions 3a, 4a between the fluid motor 1 and the counterbalance valve 6 in the first and second main circuits 3, 4 are connected by a short circuit 8 having a safety valve 7 which operates in both directions. The spring chamber 7a of the safety valve 7 is connected to the counterbalance valve 6 through the passage 9 so that the high-pressure fluid discharged by the fluid motor 1 when the fluid motor 1 is pumping is sent to the main circuit on the low-pressure side of the safety valve 7. The main circuit on the high-pressure side is prevented from having an abnormally high pressure by flowing out. In the figure, reference numeral 10 denotes a partial passage of the counterbalance valve 6, 11 denotes a tank, 12 denotes a fluid pump, and 13 denotes a lever.

With such a fluid brake device, when the operating valve 2 is set at the first position A or the second position B, the high-pressure oil of the Since the relief pressure set of the safety valve 7 becomes a high pressure set by acting on the spring chamber 7a of the safety valve 7 from the internal passage 10 of the balance valve 6, the output torque of the fluid motor 1 increases during acceleration. can do. When the operation valve 2 is set to the neutral position N, the high-pressure oil in the panel chamber 7a of the safety valve 7 flows out of the internal passage 10 of the counter balance valve 6 to the tank 11, and the safety valve 7 is set to a low pressure. Thus, shock when the fluid motor 1 is stopped can be reduced.

In such a fluid brake device, the high-pressure fluid in the main circuit on the high-pressure side acts on the panel chamber 7a of the safety valve 7, so that the set pressure of the safety valve 7 increases in accordance with the pressure of the fluid acting on the panel chamber 7a. If the set pressure of the safety valve 7 becomes infinitely high at the time of reverse operation, the shock increases and the fluid motor 1 may be damaged.

For example, in FIG. 1, when the operation valve 2 is in the first position A, the lever 13 is operated to move the operation valve 2 through the neutral position N to the second position B in a reverse operation. However, high-pressure oil is supplied to the second main circuit 4 where the brake pressure is applied, and the fluid pressure acting on the panel chamber of the safety valve 7 increases, so that the set pressure of the safety valve 7 increases. The fluid motor 1 may become large, and the fluid motor 1 may be damaged.

That is, when the operation valve 2 is at the first position A, the first main circuit 3 becomes high pressure, the second main circuit 4 is connected to the tank 11 from the counter balance valve 6, and the fluid motor 1 It is driven by high-pressure oil in one main circuit 3. In this state, when the operating valve 2 is moved to the second position B through the neutral position N, the discharge pressure oil of the fluid pump 12 is supplied to the second main circuit 4, and the fluid motor 1 rotates by inertia. 4a between the fluid motor 1 and the counterbalance valve 6 in the second main circuit 4 The high pressure oil supplied to the second main circuit 4 is shut off by the intermittent valve 6 and the high pressure oil supplied to the second main circuit 4 is supplied from the internal passage 10 and the passage 9 of the counter balance valve 6 to the panel chamber 7 a of the safety valve 7. As the safety valve 7 is set to the high pressure set immediately, the shock when the inertia rotating fluid motor 1 stops is increased. Also, since the peak pressure becomes high, each part may be damaged.

Structure of the invention

Therefore, an object of the present invention is to provide a migrating brake device that can solve the above-mentioned problems.

Another object of the present invention is to provide a fluid brake that does not generate a shock when a fluid motor stops when a control valve is reversely operated and does not generate a high peak pressure. is there.

To achieve the above object, according to a first configuration of the present invention, a fluid motor and an operation valve are communicated with each other through first and second main circuits, and the first and second main circuits are connected to each other. In addition to providing a check valve and a counterbalance valve, the part of the first and second main circuits closer to the fluid motor than the check valve is connected by a short-circuit path with a safety valve that operates in both directions. The set pressure is raised by the fluid pressure supplied to the panel chamber of the safety valve, and the panel chamber is connected to the counterbalance valve through a passage. A fluid brake device provided with a slow return valve that allows fluid to flow out smoothly from the panel panel chamber is provided.

Preferably, the operation valve is in a neutral position, a first position for supplying a discharge fluid of a fluid pump to a first main circuit, and a first position for supplying a discharge fluid of the fluid pump to a second main circuit. Be switched to the second position, The counterbalance valve is in the shut-off position when the operating valve is in the neutral position, in the first position communicating the passage with the first main circuit when the operating valve is in the first position, and when the operating valve is in the second position. At times, it is configured to be at the second position communicating the passage with the second main circuit.

According to the second configuration of the present invention, a fluid motor having a braking mechanism and an operation valve for selectively supplying a hydraulic pressure supplied from a hydraulic pressure source to the fluid motor to switch an operation direction of the fluid motor are provided. First and second main circuits communicating with each other;

A chip provided in each of the first and second main circuits, for permitting a flow of a working fluid from a hydraulic source toward the fluid motor, and for preventing a flow of the working fluid from the fluid motor toward the hydraulic source. And a first valve and a second valve are provided in the first and second main circuits in parallel with the check valve, and when the operation valve is set to a neutral position, the fluid valve and the hydraulic source are shut off. A brake counter balance valve that operates the brake mechanism of the fluid motor to brake by the output of high pressure from the fluid motor;

A short circuit that short-circuits the first and second main circuits,

A safety valve provided in the short circuit, operable with respect to a flow of a bidirectional working fluid between the first and second main circuits;

Means for introducing a hydraulic pressure into the set pressure generation chamber of the safety valve to control the set pressure of the safety valve;

A fluid brake device is provided, wherein the fluid brake device is provided in the hydraulic pressure introducing means and is configured to regulate a rising speed of a set pressure generated in the set pressure generating chamber.

In this case, the hydraulic pressure introducing means is provided in the first and second main circuits. The hydraulic pressure corresponding to the hydraulic pressure on the high pressure side can be introduced into the set pressure generating chamber. Further, the means for regulating the rising speed of the set pressure can be constituted by means for regulating the flow rate of the hydraulic pressure introduced from the hydraulic pressure introducing means to the set pressure generating means.

According to a preferred configuration, the braking mechanism provided in the fluid motor is constituted by a shaft brake driven by hydraulic pressure introduced into the brake cylinder. In this case, it is preferable that the brake cylinder is provided with a means for constantly applying a force in the braking direction, and that the hydraulic pressure introduced into the brake cylinder acts in the braking release direction. Further, the brake cylinder is configured to be supplied with hydraulic pressure from the hydraulic pressure introducing means. Preferably, a brake switching circuit is provided in a brake control circuit between the brake cylinder and the hydraulic pressure introducing means. The brake switching valve is provided with an urging means for communicating the brake control circuit with the drain side, and a hydraulic pressure supplied from the hydraulic pressure introducing means is provided on an introduction side opposed to the urging force of the urging means. It is configured to act as power.

According to the above configuration, when the operation valve is switched to supply the discharge fluid of the fluid pump to the first or second main circuit, the discharge fluid of the fluid pump slowly acts on the panel chamber of the safety valve. Since the set pressure gradually increases, no shock or high peak pressure is generated when the fluid motor stops when the operating valve is reversely operated.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will be better understood from the following detailed description and the accompanying drawings, which illustrate embodiments of the invention. It is shown in the attached drawing The examples are not intended to identify the invention, but merely to facilitate explanation and understanding.

In the figure,

FIG. 1 is a diagram illustrating the configuration of a conventional example.

FIG. 2 is a schematic structural explanatory view showing an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to FIG. In the following description, the same members as those in the conventional example shown in FIG. 1 are denoted by the same reference numerals as the members in FIG.

The fluid motor 1 is provided with a shaft brake 20.轴 The brake 20 is configured such that the brake pad 22 is pressed against the brake drum 21 with the brake cylinder 23. The brake cylinder 23 is pushed in the braking direction by the panel 24, and is pushed in the non-braking direction by the pressure oil in the pressure receiving chamber 25.

The pressure receiving chamber 25 of the brake cylinder 23 is connected to the passage 9 communicating the counterbalance valve 6 and the panel chamber 7a of the safety valve 7 by a surface path 26, and a brake switching valve 27 is connected to this circuit 26. Is provided.

The brake switching valve 27 is normally held at a braking position D which connects the circuit 26 to the tank 11 by a panel 28. The pressure oil supplied from the circuit 26 is acting on the pressure receiving portion 27a of the brake switching valve 27, and the hydraulic pressure acting on the pressure receiving portion 27a exceeds the urging force of the panel 28. Occasionally, it is displaced to the non-braking position E which shuts off the circuit 26 and the tank 11.

The passage 9 is provided with a slow return valve 29. The slow return valve 29 includes a throttle 30 and a short-circuit path 32 having a tick valve 31 for short-circuiting before and after the throttle 30. Safety valve 7 The fluid gradually flows into the panel chamber 7a, and the fluid flows out smoothly from the panel chamber 7a of the safety valve 7.

Next, the operation of the above configuration will be described.

(1) When operation valve 2 is in neutral position N

When the counterbalance valve 6 is in the shut-off position F and the fluid motor 1 is stopped, the high-pressure fluid does not act on the passage 9 and the brake switching valve 27 is in the braking position D and the pressure receiving chamber of the brake cylinder 22 is in operation. Since 25 communicates with the tank 11, the shaft brake 20 enters the braking state, and the panel chamber 7 a of the safety valve 7 communicates with the tank 11 to set a low pressure. (2) When operation valve 2 is in the first position A

The fluid discharged from the fluid pump 12 is supplied to the first main circuit 3 so that the counter balance valve 6 is at the first position G, and the fluid discharged from the fluid pump 12 is the internal passage 10 of the counterbalance valve 10. The safety valve 7 then flows into the passage 9 and becomes a high-pressure set.

At the same time, the fluid discharged from the fluid pump 12 flows into the circuit 26, and the brake switching valve 27 is in the non-braking position E, and the shaft brake 20 is in the non-braking state.

(3) When operating valve 2 is in second position B

The fluid discharged from the fluid pump 12 is supplied to the second main circuit 4 so that the counterbalance valve 6 is at the second position H, and the fluid discharged from the fluid pump 12 is passed through the internal passage 10 of the counterbalance valve 6. Flowing through 9, safety valve 7 becomes a high pressure set.

At the same time, the fluid discharged from the fluid pump 12 flows into the circuit 26, and the brake switching valve 27 is in the non-braking position E, and the shaft brake 20 is in the non-braking state. (4) When the operation valve 2 at the first position A is set to the neutral position N

Since the counterbalance valve 6 is in the shut-off position F and the fluid discharged from the fluid pump 12 is not supplied to the passage 9 and the safety valve 7 is set to the low pressure set and the shaft brake 20 is put into the braking state at the same time as described above, The fluid motor 1 with inertia can be stopped without shock.

The same applies to the case where the operation valve 2 which is the second position B is set to the neutral position N.

(5) Operate the operation valve 2 at the first position A through the neutral position N and move it to the second position B

When

When the control valve 2 passes through the neutral position N, the high-pressure fluid in the panel chamber 7a of the safety valve 7 flows out to the tank 11 and the safety valve 7 is set to the low pressure set, and the control valve 2 moves to the second position B. The discharge fluid of the fluid pump 12 flows into the passage 9 from the internal passage 10 at the second position H of the force balance valve 6 when it is connected. Since the pressure gradually acts on the panel chamber 7a, the set pressure of the safety valve 7 gradually increases.

For this reason, the pressure of the fluid discharged from the fluid motor 1 that is rotating by inertia to the first main circuit 3 does not become a high pressure, but flows from the safety valve 7 to the second main circuit 4, and the motor rotates by inertia. The fluid motor 1 can be stopped without shock, and immediately before the stop, the safety valve 7 becomes a high-pressure set and the fluid pressure in the second main circuit 4 becomes high. Can accelerate.

The same applies when the operation valve 2 at the second position B is set to the first position A through the neutral position N. In the above embodiment, the passage 9 is connected to the tank by the brake switching valve 27, but the counterbalance valve 6 may be connected to the tank as in FIG.

As described above, when the discharge fluid of the fluid pump 12 is supplied to the first or second main circuit 3 or 4 by switching the operation valve 2, the discharge fluid of the fluid pump 12 is supplied to the panel chamber 7a of the safety valve 7. Since the set pressure gradually increases due to the slow action, a shock occurs when the fluid motor 1 stops when the operation valve 2 is reversely operated, or a high peak pressure is generated. There is nothing to do.

Although the present invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various modifications, omissions, and additions can be made to the disclosed embodiments without departing from the spirit and scope of the present invention. It is obvious in. Therefore, the present invention is not limited to the above embodiments, but should be understood to include the scope defined by the elements recited in the claims and the equivalents thereof.

Claims

The scope of the claims

1. The fluid motor and the operating valve communicate with each other in first and second main circuits, and the first and second main circuits are provided with a chip valve and a counterbalance valve, and the first and second main circuits are connected to each other. Fluid from check valve in second main circuit

(5) The motor-side part is communicated with a short circuit provided with a safety valve that operates in both directions, and the safety valve is set so that the set pressure is increased by the fluid pressure supplied to the panel chamber of the safety valve. A fluid brake device that is connected to a counterbalance valve through a passage and has a slow return valve through which fluid flows slowly into the panel chamber and flows out smoothly from the panel chamber.

2. The operation valve is in a neutral position, a first position for supplying the fluid discharged from the fluid pump to the first main circuit, and a second position for supplying the fluid discharged from the fluid pump to the second main circuit. The counter balance valve shall be switched to the shut-off position when the operating valve is in the neutral position, and the operating valve shall be in the first position.

When the valve is in the first position, it is in the first position communicating the passage with the first main circuit, and when the operating valve is in the second position, it is in the second position communicating the passage with the second main circuit. The fluid brake device according to claim 1, wherein:

3. Fluid motor equipped with a braking mechanism and hydraulic pressure supplied from a hydraulic pressure source are selectively supplied to the fluid motor to switch the cultivation direction of the fluid motor.

20 first and second main circuits communicating between the operating valves to be replaced,

A check valve provided in each of the first and second main circuits, for permitting the flow of working fluid from a hydraulic source to the fluid motor, and for preventing the flow of working fluid from the fluid motor to the hydraulic source; 25 is provided in the first and second main circuits in parallel with the check valve, and when the operation valve is in the neutral position, And a brake counter balance valve for operating the braking mechanism of the fluid motor to brake by the output of the high pressure from the fluid motor; and

A short circuit that short-circuits the first and second main circuits,

A fluid brake device provided in the hydraulic pressure introducing means and configured to regulate a rising speed of a set pressure generated in the set pressure generating chamber.

4. The fluid brake device according to claim 3, wherein the hydraulic pressure introducing means introduces a hydraulic pressure corresponding to a high-pressure side hydraulic pressure of the first and second main circuits into the set pressure generation chamber. .

5. The means according to claim 4, wherein the means for regulating the rising speed of the set pressure is constituted by means for regulating the flow rate of the hydraulic pressure introduced from the hydraulic pressure introduction means to the set pressure generation means. Fluid brake equipment described

6. The fluid brake device according to claim 3, wherein the braking mechanism provided in the fluid motor is configured by an axis brake driven by hydraulic pressure introduced into a brake cylinder.

7. The braking mechanism provided in the fluid motor is constituted by a shaft brake driven by a hydraulic pressure introduced into a brake cylinder, and the brake cylinder is provided with a means for constantly applying a force in a braking direction. The hydraulic pressure introduced into the brake cylinder acts in the braking release direction. The fluid brake device according to claim 4, wherein the fluid brake device is configured as follows.

8. The fluid brake device according to claim 7, wherein a hydraulic pressure is supplied to the brake cylinder from the hydraulic pressure introducing means.

9. A brake switching circuit is provided in a brake control circuit between the brake cylinder and the hydraulic pressure introducing means, and the brake switching valve has an urging means for connecting the brake control circuit to a drain side, and 9. The fluid brake device according to claim 8, wherein the hydraulic pressure supplied from the hydraulic pressure introducing means acts as an operating force on the introduction side opposite to the urging force of the urging means.