JPH09264346A - Brake device of hydraulic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time difference in releasing a brake, and to provide the braking torque suitable for the spring force. SOLUTION: A piston pressure bearing chamber 8 of a cylinder 5 for braking is connected to an internal drain passage 10 of a hydraulic motor 1 by a drain circuit 9, and the air left in the circuit connected to the piston pressure bearing chamber 8 is discharged into the internal drain passage 10. A piston 6 of the cylinder 5 for braking is moved in the braking direction in a short time to reduce the time difference in releasing a brake and to obtain the braking torque suitable for the spring force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device for a hydraulic motor used as a turning hydraulic motor for turning an upper body of a hydraulic excavator.

[0002]

2. Description of the Related Art As a brake device for a hydraulic motor, a rotary side friction plate is provided at a rotary part of the hydraulic motor, a fixed side friction plate is provided at a fixed part such as a hydraulic motor housing, and a brake cylinder is provided. The piston of the work cylinder is moved by a spring in the braking direction in which the fixed side friction plate is pressed against the rotating side friction plate, and pressure oil is supplied to the piston pressure chamber to separate the fixed side friction plate from the rotating side friction plate. Brake devices that move in the braking direction are known.

[0003]

Pressure oil is supplied to the piston pressure chamber of the brake cylinder in the above-described brake device by a switching valve or the like, and the pressure oil in the piston pressure chamber is discharged to the tank. However, air enters the circuit that connects the piston pressure chamber of the brake cylinder and the switching valve, the passage of the switching valve, and the circuit that connects the switching valve and the tank during assembly, and discharges the air to the outside (air bleeding). Since it is difficult to do so, air remains, and it takes a long time for the piston pressure receiving chamber to rise to a predetermined pressure after the brake device is not braked, and the time until the non-braking is completed becomes longer, resulting in a difference in brake release time. It becomes big.

Therefore, an object of the present invention is to provide a brake device for a hydraulic motor which can solve the above-mentioned problems.

[0005]

According to a first aspect of the present invention, a rotary side friction plate 3 is provided on a rotary portion 2 of a hydraulic motor 1.
A cylinder 5 for a brake, which is provided with a fixed-side friction plate 4 on the fixed portion, and presses and separates the fixed-side friction plate 4 from the rotating-side friction plate 3.
And the piston 6 of the brake cylinder 5 is moved by a spring 7 in the braking direction in which the fixed side friction plate 4 is brought into pressure contact with the rotation side friction plate 3, and the piston 6 is fixed by the pressure oil in the piston pressure receiving chamber 8. The plate 4 is moved in the non-braking direction so as to be separated from the rotation side friction plate 3, pressure oil supply means for supplying and stopping pressure oil to the piston pressure chamber 8 is provided, and the piston pressure chamber 8 is connected to the drain circuit 9 by a drain circuit 9. Internal drain path 1 of hydraulic motor 1
0 is a brake device for a hydraulic motor.

According to the first aspect of the present invention, the pressure oil is supplied to the piston pressure receiving chamber 8 of the brake cylinder 5 by the pressure oil supplying means so that the pressure oil supplying means and the piston pressure receiving chamber 8 are mixed in the circuit. The discharged air is discharged from the drain circuit 9 to the internal drain passage 10 of the hydraulic motor 1,
Air that has been mixed in during assembly can be completely removed.

As a result, the pressure in the piston pressure receiving chamber 8 of the brake cylinder 5 becomes a predetermined pressure in a short time, and the piston 6 quickly moves to the stroke end in the non-braking direction. .

Also, the piston 6 of the brake cylinder 5
When moving in the non-braking direction, the pressure oil in the piston pressure receiving chamber 8 flows out from the drain circuit 9 into the internal drain passage 10 of the hydraulic motor 1, so that no pressure remains in the piston pressure receiving chamber 8 or in the circuit. The fixed-side friction plate 4 is pressed against the rotating-side friction plate 3 by the spring force of the spring 7.

As a result, a braking torque commensurate with the spring force of the spring 7 can be obtained.

A second invention is a brake of a hydraulic motor, wherein the pressure oil supply means in the first invention is a hydraulic pilot valve for outputting pilot pressure oil for switching to an operation valve for supplying pressure oil to the hydraulic motor 1. It is a device.

According to the second aspect of the invention, when the hydraulic pilot valve is operated to output pilot pressure oil to switch the operating valve and rotate the hydraulic motor 1, the pilot pressure oil causes the piston 6 of the brake cylinder 5 to rotate. Moves in the non-braking direction and the braking device becomes non-braking.

As a result, when the operation of rotating the hydraulic motor 1 is performed, the brake device is not braked, and the operation is simplified.

When the hydraulic pilot valve is in the neutral position and the operation valve is in the neutral position, and the hydraulic motor 1 is stopped,
Since the pressure oil in the piston pressure receiving chamber 8 of the brake cylinder 5 flows out from the drain circuit 9 to the internal drain passage 10 of the hydraulic motor 1, the brake device can be non-braked.

A third aspect of the present invention is a hydraulic motor brake device in which the pressure oil supply means in the first aspect is a load pressure detection circuit 26 for detecting the load pressure of the hydraulic motor 1 and the working machine actuator.

According to the third aspect of the invention, when the hydraulic motor 1 is rotated to generate a load pressure or the work machine actuator is operated to generate a load pressure, the piston 6 of the brake cylinder 5 is not driven by the load pressure. It moves in the braking direction and the braking device becomes non-braking.

As a result, when the operation of rotating the hydraulic motor 1 or the operation of operating the work implement actuator is performed, the brake device is not braked, so that the operation is simplified.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a rotary side friction plate 3 is provided on a rotary portion 2 of a hydraulic motor 1 for turning, and a fixed side friction plate 4 is provided on a fixed portion such as a hydraulic motor housing. A brake cylinder 5 is provided. The piston 6 of the brake cylinder 5 is moved by a spring 7 in the braking direction in which the fixed side friction plate 4 is pressed against the rotating side friction plate, and the fixed side friction plate 4 is rotated by the pressure oil in the piston pressure receiving chamber 8. It is moved in the non-braking direction away from 3.

A drain circuit 9 is provided in the piston pressure receiving chamber 8.
The drain circuit 9 is connected to the internal drain passage 10 of the hydraulic motor 1, and the drain circuit 9 is provided with a throttle 11. The piston pressure receiving chamber 8 is connected and controlled by a switching valve 12 to one of a hydraulic pressure source 13 and a tank 14.

Next, the operation will be described. When the switching valve 12 is set to the illustrated first position a, the pressure oil from the hydraulic pressure source 13 is supplied from the switching valve 12 to the piston pressure receiving chamber 8 via the circuit 15 and the brake is not applied. At this time, the air remaining in the circuit 15 is discharged from the drain circuit 9 to the internal drain passage 10 of the hydraulic motor 1, so that the time difference for releasing the brake becomes small. When the switching valve 12 is set to the second position b from this state, the pressure oil in the piston pressure receiving chamber 8 flows out to the tank 14, but at the same time, it flows from the drain circuit 9 to the internal drain passage 10 of the hydraulic motor 1. , The fixed side friction plate 4 is rotated by the spring force 7 even when the pressure remains in the circuit 15 described above.
A strong braking force is applied to obtain a braking torque commensurate with the spring force.

FIG. 2 shows a second embodiment of the present invention, in which a turning operation valve 21 and a working machine operation valve 22 are provided in parallel in a discharge passage 20a of a hydraulic pump 20 driven by an engine M. Pressure oil is supplied to the working hydraulic actuator 1 and a working machine actuator such as a working machine cylinder (not shown), and a pressure compensating valve 23 is provided on the inlet side of each operation valve. The pressure compensating valve 23 is a conventionally known one having a check valve portion 24 and a pressure reducing valve portion 25, and has a load pressure P ₀ of its own hydraulic actuator and a load pressure P of a load pressure detecting circuit 26.
_1. Compensate for pressure. The highest load pressure is introduced into the load pressure detection circuit 26 when a plurality of hydraulic actuators are simultaneously operated.

The hydraulic pump 20 is of a variable displacement type,
The capacity is controlled to increase / decrease by swinging the swash plate 27 with the control piston 28, and the control piston 28 slides in the capacity increasing / decreasing direction by the self-discharge pressure supplied to the small diameter pressure receiving chamber 29 and the large diameter pressure receiving chamber 30, The large-diameter pressure receiving chamber 30 is supplied with self-discharge pressure oil by a control valve 31, and the control valve 31 is switched and operated so that the differential pressure between the load pressure and the self-discharge pressure becomes constant.

By thus controlling the capacity of the hydraulic pump 20 and providing the pressure compensating valve 23, a plurality of operating valves are simultaneously operated so that the pressure oil discharged from one hydraulic pump 20 is supplied to a plurality of hydraulic actuators. It can be supplied at a diversion ratio proportional to the opening area of the operating valve.

In the discharge passage 40a of the pilot hydraulic pump 40 driven by the engine M, a turning hydraulic pilot valve 41 and a working machine hydraulic pilot valve 42 are provided. The first and second output circuits 43 and 44 are connected to the first and second pressure receiving portions 21a and 21b of the turning operation valve 21, and the third and fourth output circuits 45 and 46 of the hydraulic pilot valve 42 for the working machine are connected. Is connected to the first and second pressure receiving portions 22a and 22b of the working machine operation valve 22.

The first output circuit 43 and the second output circuit 44
Is connected to the inlet side of the first shuttle valve 47, and the outlet side of the shuttle valve 47 and the third output circuit 45 are connected to the second shuttle valve 4
8 is connected to the inlet side, and the output side of the second shuttle valve 48 is connected to the piston pressure receiving chamber 8 of the brake cylinder 5 by a circuit 49.

Next, the operation will be described. The turning hydraulic pilot valve 41 is operated to output pilot pressure oil to the first output circuit 43 or the second output circuit 44, whereby the turning operation valve 21 is switched to the first position B or the second position C. The hydraulic motor 1 rotates normally and reversely.

At the same time, the pilot pressure oil output from the turning hydraulic pilot valve 41 flows into the circuit 49 and is supplied to the piston pressure receiving chamber 8 of the brake cylinder 5, so that the brake device is not braked. At this time, the circuit 49
The air remaining in is discharged.

In the above-mentioned state, a part of the pressure oil in the piston pressure receiving chamber 8 of the brake cylinder 5 is drain circuit 9.
More outflow to the internal drain passage 10 of the hydraulic motor 1,
Since the drain circuit 9 is provided with the throttle 11, the pressure in the piston pressure receiving chamber 8 does not drop.

When the hydraulic motor 1 rotates and the brake device is in the non-braking state, if the turning hydraulic pilot valve 41 is operated to the neutral position, pilot pressure oil is not output and the turning operation valve 21 is set to the neutral position A. Then, the hydraulic motor 1 is stopped.

As a result, the pressure oil is not supplied into the piston pressure receiving chamber 8 of the brake cylinder 5, and the pressure oil inside the piston pressure receiving chamber 8 flows out from the drain circuit 9 into the internal drain passage 10 of the hydraulic motor 1. The brake device can be braked without the pressure oil in the circuit 49 flowing out to the tank by the second shuttle valve 48. When the hydraulic pilot valve 42 for the working machine is operated to output the pilot pressure oil to the third output circuit 45 to switch the working machine operating valve 22 to operate the working machine cylinder, the brake is applied similarly to the above. The device works.

FIG. 3 shows a third embodiment of the present invention, in which the piston pressure receiving chamber 8 of the brake cylinder 5 is connected to the load pressure detecting circuit 2.
It is connected to 6. With this configuration, the brake device can be non-braked by the load pressure of the turning hydraulic motor 1 and the load pressure of the working machine cylinder.

The specific structure of the diaphragm 11 will be described. As shown in FIG. 4, an annular recess 51 is formed on the outer peripheral surface 50a of the sleeve 50, and the annular recess 51 is open to the inner peripheral surface 50b through a hole 52. A piston 53 is fitted in the sleeve 50. This piston 53 has a large diameter part 5
4 has a stepped shape having a small diameter portion 55 and a hole 56 in the shaft center.
Is formed. A small hole 57 is open to the small diameter portion 55 near the bottom of the hole 56, and a plurality of balls 58 are fitted in the hole 56 of the piston 53.

The large-diameter portion 54 of the piston 53 is sealed on the inner peripheral surface 50b of the sleeve 50 with a sealing material 59, the small diameter 57 is opened in the hole 52, and the hole 56 is formed in the small hole 6 of the sleeve 50.
0 is opened, and the pressure oil flows in through the hole 52 and the small hole 5
7, through the gap between the hole 56 and the ball 58 to flow out from the small hole 60.

Because of this, the difference between the diameter of the hole 56 and the diameter of the ball 58 forms a gap between the hole 56 and the ball 58, and the flow is narrowed when flowing through the gap, so that a compact and high drawing effect is achieved. It becomes the diaphragm obtained.

Further, when the pressure oil flows through the gap between the hole 56 and the ball 58, the ball 58 rotates, so that the foreign matter entering the gap is discharged, so that the foreign matter is not clogged and malfunction occurs. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of the present invention.

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

FIG. 3 is an explanatory view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a specific structure of a diaphragm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hydraulic motor 2 ... Rotating part 3 ... Rotation side friction plate 4 ... Fixed side friction plate 5 ... Brake cylinder 6 ... Piston 7 ... Spring 8 ... Piston pressure receiving chamber 9 ... Drain circuit 10 ... Internal drain passage 11 ... Throttle 12 ... Switching valve 13 ... Hydraulic source 14 ... Tank 15 ... Circuit 20 ... Hydraulic pump 21 ... Swing operation valve 26 ... Load pressure detection circuit 41 ... Swing hydraulic pilot valve 42 ... Working machine hydraulic pilot valve 47 ... First shuttle Valve 48 ... Second shuttle valve 49 ... Circuit 50 ... Sleeve 53 ... Piston 56 ... Hole 58 ... Ball.

Claims (3)

[Claims] 1. A brake for providing a rotating side friction plate 3 to a rotating portion 2 of a hydraulic motor 1, a fixed side friction plate 4 to a fixed portion, and pressing and separating the fixed side friction plate 4 to and from the rotating side friction plate 3. A brake cylinder 5 is provided, and the piston 6 of the brake cylinder 5 is moved by a spring 7 in the braking direction in which the fixed side friction plate 4 is brought into pressure contact with the rotation side friction plate 3, and the piston 6 is moved by the pressure oil in the piston pressure receiving chamber 8. The fixed side friction plate 4 is moved in a non-braking direction so as to be separated from the rotation side friction plate 3, pressure oil supply means for supplying / stopping pressure oil to / from the piston pressure chamber 8 is provided, and the piston pressure chamber 8 is drained. Hydraulic motor 1 in circuit 9
A brake device for a hydraulic motor, wherein the brake device is connected to the internal drain passage 10. 2. The brake device for a hydraulic motor according to claim 1, wherein the pressure oil supply means is a hydraulic pilot valve that outputs pilot pressure oil for switching to an operation valve that supplies the pressure oil to the hydraulic motor 1. 3. The brake device for a hydraulic motor according to claim 1, wherein the pressure oil supply means is a load pressure detection circuit 26 for detecting the load pressure of the hydraulic motor 1 and the working machine actuator.