JPS63266174A - Brake for hydraulic motor - Google Patents

Abstract

PURPOSE:To enable working of a brake irrespective of a self pressure, by a method wherein a cylinder block is rotatably disposed in a motor case, a hydraulic brake to fix a cylinder block is provided, and brake oil is fed from an external hydraulic source. CONSTITUTION:A cylinder block 13 formed by slidably engaging pistons 15 internally of a plurality of cylinder holes 14 is secured on a shaft 12 rotatably supported to a motor case 10 and an end cover 11 in a hydraulic motor for running a hydraulically-driven vehicle. Brake discs 18 to form a brake 22 are alternately mounted to the motor case 10 and the cylinder block 13, and a brake piston 19 is engaged with the motor case 10 to form a pressure chamber 20. The pressure chamber 20 is communicated to an external hydraulic source 24 and a tank 25 through an electromagnetic switching valve 23. A pressure fed to the pressure chamber 20 can be set to a low value irrespective of a self oil pressure to drive the hydraulic motor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a braking device for a hydraulic motor with a built-in brake used as a traveling motor for an upper swing type hydraulically driven vehicle such as a power shovel.

[Conventional technology]

The top swing type hydraulic drive vehicle is driven by a travel motor, and since this vehicle may operate on slopes, the travel motor has a built-in brake, and when the vehicle stops on a slope, the brake is applied to stop the vehicle. I try not to run under my own weight.

As mentioned above, a braking device for a hydraulic motor with a built-in brake performs braking by moving the brake piston in the direction of compressing the brake disc using a spring force, and also rotates the hydraulic motor into the pressure receiving chamber of the brake piston. A portion of the pressure oil for this purpose, that is, self-pressure oil, is supplied so that the brake moves against the spring force and becomes non-braking.

In this way, when the hydraulic motor does not rotate, it is held and when it starts rotating, it is not braked.
When used as a running motor, it is possible to prevent the vehicle from running on a slope due to its own weight.

[Problem that the invention seeks to solve]

In such a braking device for a hydraulic motor, self-pressure oil is supplied to the pressure receiving chamber of the brake piston, so the supplied pressure oil has a high pressure proportional to the running torque. For this reason, it is necessary to make the brake components such as the brake piston, the end cover of the hydraulic motor, and their tightening bolts strong enough to withstand the high pressure hydraulic force, which increases the weight and increases the overall length of the hydraulic motor. The length increases, the installation space becomes larger, and the cost increases.

In addition, when the pressure oil to rotate the hydraulic motor is supplied, the brake is not applied, and when the pressure oil supply is stopped, the brake is applied, so the timing of braking and non-braking is constant and cannot be adequately controlled, so it suddenly stops. The vehicle may be braked and a shock may occur.
Braking may be delayed and the vehicle may rotate due to external force, for example, the vehicle may run under its own weight on a slope.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a braking device for a hydraulic motor with a built-in brake, which is capable of braking and non-braking without using self-pressure oil and can control the timing as desired.

[Means and actions for solving the problem] The pressure receiving chamber of the brake piston constituting the brake is communicated with an external hydraulic pressure source via a switching valve, and the switching valve supplies pressurized oil from the external hydraulic source to the pressure receiving chamber. This allows the brake to operate regardless of self-pressure.

〔Example〕

As shown in FIG. 2, the upper swing type hydraulically driven vehicle has an upper body 3 attached to a running body 2 which is driven by a running motor 1 so as to be able to swing freely by a swing motor 4. As shown in Fig. 1, it is a hydraulic motor with a built-in brake.

That is, a shaft 12 is rotatably installed between the motor case 10 and the end cover 11, a cylinder block 13 is spline-fitted to the shaft 12, and a piston 15 fitted into the cylinder hole 14 of the cylinder block 13 is inserted into the valve plate. 16, and the valve plate 16 is swung by a switching piston 17 to control the rotational direction and rotational speed of the shaft 12. A brake disc is attached to the motor case 10 and the cylinder block 13. 18
At the same time, the pre-kissed stones 19 are fitted and inserted into the motor case 10 to form a pressure receiving chamber 20, and the springs 2 and 2 are attached alternately.
1, the brake disc 18 is slidably biased in a direction to press the brake disc 18, thereby forming a brake 22.

The pressure receiving chamber 20 is connected to an external hydraulic power source 2 via an electromagnetic switching valve 23.
4 and the tank 25, and the electromagnetic switching valve 23 is held in the drain position I, which communicates the pressure receiving chamber 2o with the tank 25 by a spring force, and when the solenoid 23a is energized, the pressure receiving chamber 2
o is switched to supply position H, which communicates with external hydraulic power source 24.

Because of this, the pressure oil from the external hydraulic source 24 is supplied to the pressure receiving chamber 21 of the brake 22, and the pressure can be set to a low level regardless of the self-hydraulic pressure that drives the hydraulic motor, so that the brake piston 19 and the end The force acting on the cover 11 and its tightening bolt 11a can be reduced to weaken its strength.

In addition, by energizing the solenoid 23a, the electromagnetic switching valve 2
3 to the supply position H, the brake 22 can be made non-braking, and if the solenoid 23a is demagnetized and the electromagnetic switching valve 23 is set to the drain position ■, the brake 22 can be braked.
You can change the timing arbitrarily.

FIG. 3 shows a second embodiment, in which the inlet and outlet ports la and lb of the traveling motor 1, which is the hydraulic motor with built-in brake shown in FIG. 1, are connected to the first and second passages 30, 31, These first and second paths 30, . 31 is connected to a hydraulic pump 32 via an operation valve (not shown), and first and second pressure sensors 33 and 34 are connected to the first and second passages 30 and 31.
The detected hydraulic pressure is sent to the controller 35 to calculate the differential pressure between the artificial hydraulic pressure and the outlet hydraulic pressure. When the differential pressure becomes less than the set pressure, the controller 35 switches the solenoid of the electromagnetic switching valve 23. A demagnetizing signal is output to 23a.

With this configuration, when the differential pressure between the inlet 1a and the outlet 1b of the traveling motor 1 becomes lower than the set value, the solenoid 23a of the electromagnetic switching valve 23 is demagnetized and switched to the drain position I, and the pressure receiving chamber 20 of the brake 22 is Tank 2 is not supplied with pressure oil.
5, the brake 22 is braked by the spring 21.

On the other hand, when the vehicle exits the vehicle, it coasts due to its own weight, that is, it overruns, and the driving motor 1 acts as a pump, reducing the hydraulic pressure at the inlet 1a and reducing the differential pressure between the inlet 1a and the outlet 1b. Since the pressure is below the set pressure, the brake 22 is automatically applied as described above to prevent overrun.
Since there is no need to provide a counterbalance valve as in the conventional case, costs can be reduced and overruns can be reliably prevented.

In other words, if a counterbalance valve is provided to prevent overruns, the counterbalance valves are complicated and expensive, which increases the cost, and the hunting phenomenon occurs, making it impossible to reliably prevent overruns.

〔Effect of the invention〕

The pressure oil discharged from the external hydraulic power source 24 is transferred to the pressure receiving chamber 20 of the brake 22.
Since the self-pressure of the hydraulic motor is not supplied to the pressure receiving chamber 20, large force is not applied to the brake components, the end cover, and their tightening bolts, thereby reducing their strength. The weight can be reduced without requiring much, the total length can be shortened, the installation space can be reduced, and the cost can be reduced.

Furthermore, since the brake can be operated regardless of the timing of supply of self-pressure to the hydraulic motor, the timing of the operation can be adjusted as desired.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a sectional view of a hydraulic motor, FIG. 2 is a front view of an upper swing type hydraulically driven vehicle, and FIG. 3 is a second embodiment of the present invention. FIG. 10 is a motor case, 11 is an end cover, 12 is a shaft, 13 is a cylinder block, 15 is a piston, 19
is the brake piston, 2o is the pressure receiving chamber, 22 is the brake,
24 is an external hydraulic power source.

Claims (1)

[Claims] Bolt the end cover 11 to the motor case 10,
A cylinder block 13 having a plurality of pistons 15 is rotatably disposed therein, and a shaft 12 is connected to the cylinder block 13.
A brake 22 is provided to fix the cylinder block 13 at
A braking device for a hydraulic motor, characterized in that a pressure receiving chamber 20 is communicated with an external hydraulic power source 24 via a switching valve.