JPH063765U - Vehicle parking brake release device - Google Patents

Abstract

(57) [Summary] [Purpose] Temporarily release the parking brake using hydraulic pressure. [Constitution] While the vehicle is traveling, the hydraulic pressure from the pump 13
It is supplied from the parking brake valve 14 to the brake chamber 12 via the switching valve 23. The brake pad 9 is separated from the rotating disc 8. When the engine is stopped, the hydraulic pressure is not supplied from the pump 13.
The parking brake 2 is activated by the spring 15. When the emergency escape lever 27 is operated, the switching valve 23 is switched, and the accumulator 22 and the brake chamber 12 communicate with each other. The hydraulic pressure accumulated in the accumulator 22 is supplied to the brake chamber 12 via the switching valve 23. This allows the piston rod 11
Is extended, the brake pad 9 is separated from the rotary disc 8, and the parking brake 2 is released.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a releasing device that releases a parking brake when the parking brake operates when the engine is stopped in a parking brake that uses hydraulic pressure and is used in a cargo handling vehicle such as a wheel loader.

[0002]

[Prior art]

 Generally, a brake device for a cargo handling vehicle such as a wheel loader is provided with a service brake that is driven when an operator steps on a foot brake during normal vehicle operation, and a parking brake that is operated during parking.

Service brakes are attached directly to each wheel. On the other hand, as shown in FIG. 2, the parking brake 2 is arranged at the end of the output shaft 4 of the transmission 3. In the figure, 5 is a torque converter, 6 is a cargo handling pump, and 7 is a brake flange.

Here, the parking brake 2 is a negative brake in order to have a light operating force and an emergency brake function, and as shown in FIG. 3, a rotary disc 8 fixed to the output shaft 4, A brake pad 9 that abuts the rotating disk 8 to stop the rotation of the output shaft 4, a crank 10 that presses and separates the brake pad 9 from the rotating disk 8, and a piston rod 11 connected to the crank 10. A spring chamber 12 for moving and a parking brake valve 14 for switching the supply of hydraulic pressure from the pump 13 to the spring chamber 12 are provided.

The spring chamber 12 is internally provided with a spring 15 for urging the piston rod 11 in a direction in which the brake pad 9 is pressed against the rotating disk 8.

In the figure, 16 is a parking brake lever and 17 is a regulator valve.

When the engine is running, the hydraulic pressure from the pump 13 is supplied to the spring chamber 12 via the parking brake valve 14, and the piston rod 11 is pushed against the spring 15. Therefore, the brake pad 9 is separated from the rotary disc 8 and the parking brake is not operating.

During parking, the parking brake lever 16 is operated to switch the parking brake valve 14 to shut off the hydraulic pressure to the spring chamber 12. Then, the piston rod 11 is shortened by the spring 15, the brake pad 9 is pressed against the rotating disc 8, and the parking brake is braked.

[0009]

[Problems to be solved by the device]

 In the above-mentioned conventional technique, the parking brake is activated by the hydraulic pressure of the pump 13 driven by the engine. Therefore, if the engine stops due to some trouble, the parking brake is also activated at the same time.

Therefore, when trying to move the vehicle, since the parking brake is applied, it is very difficult to move the vehicle by towing. Also, even if you try to remove the brake linkage to release the operation of the parking brake, the spring force is too strong and dangerous.

In view of the above, it is an object of the present invention to provide a parking break releasing device for a vehicle that can temporarily release the operation of the parking brake when the parking brake is operated by stopping the engine.

[0012]

Means for Solving the Problems The problem solving means according to the present invention is, as shown in FIG. 1, a parking brake 2 for braking a wheel, an operating body 20 for operating a parking brake 2 by switching a fluid pressure, and an operating body 20. An urging body 15 for urging the body 20 in the parking brake braking direction, and a fluid pressure supply means 21 for supplying a fluid pressure to the operating body 20 to keep the parking brake 2 in a non-braking state against the urging body 15. And an accumulator 22 for accumulating a fluid pressure for operating the service brake 1 is connected to the operating body 20, and a flow path from the accumulator 22 to the operating body 20 and a fluid pressure supply means 21 to the operating body 20 are provided. A switching valve 23 for switching the flow path is provided.

[0013]

[Action]

 In the above problem solving means, while the vehicle is traveling, the fluid pressure is supplied to the actuation body 20 by the fluid pressure supply means 21, and the parking brake 2 is not operated. At this time, the fluid pressure is accumulated in the accumulator 22.

Here, if the engine stops due to some trouble, the supply of fluid pressure to the actuation body 20 is cut off, and the urging body 15 operates the parking brake 2.

Therefore, when the emergency escape lever 27 is operated in order to allow the vehicle to be towed, the switching valve 23 is switched, and the accumulator 22 and the actuation body 20 communicate with each other. Then, the hydraulic pressure accumulated in the accumulator 22 is supplied to the operating body 20 via the switching valve 23. As a result, the parking brake 2 is released and the vehicle can be moved.

As described above, by using the accumulator mounted for the service brake, the parking brake can be temporarily released and the vehicle can be towed and moved to a place where it does not interfere with traffic in an emergency.

[0017]

【Example】

 FIG. 1 is a hydraulic circuit diagram of a brake device showing an embodiment of the present invention. It should be noted that the same components as those of the conventional one are designated by the same reference numerals.

As shown in FIG. 1, the parking brake mechanism in the brake device according to the present embodiment includes a parking brake 2 that brakes the output shaft 4 of the transmission 3 and an operating body 20 that operates the parking brake 2 by switching the hydraulic pressure. And an urging body 15 for urging the operating body 20 in the parking brake braking direction, and a fluid pressure for supplying the hydraulic pressure to the operating body 20 to resist the urging body 15 and keep the parking brake 2 in the non-braking state. An accumulator 22 having a supply means 21 and accumulating hydraulic pressure for operating the service brake 1 is connected to the actuation body 20, and a flow path from the accumulator 22 to the actuation body 20 and a fluid pressure supply means 21 to the actuation body 20. A switching valve 23 for switching between the flow path and the flow path is provided.

The parking brake 2 and its hydraulic system are the same as the conventional ones, and the parking brake 2 includes a rotary disk 8 fixed to the output shaft 4 of the transmission 3 and an output shaft that contacts the rotary disk 8. It consists of a brake pad 9 for stopping the rotation of 4.

The actuating body 20 includes a crank 10 that presses and separates the brake pad 9 from and into the rotating disc 8, and a spring chamber 12 that moves a piston rod 11 connected to the crank 10. A spring 15 is installed in the spring chamber 12 as an urging body.

The fluid pressure supply means 21 includes a pump 13 driven by an engine, a parking brake valve 14 that intermittently supplies hydraulic pressure from the pump 13 to the spring chamber 12, and a parking brake lever that switches the parking brake valve 14. 16 and.

The service brake 1 is a drum-type or disc-type brake, and its hydraulic system is provided with a brake valve 26 for controlling the hydraulic pressure generated by the pump 13 according to how the brake pedal 25 is depressed. The hydraulic pressure is supplied to the brake chamber of the brake 1 to generate the braking force.

An accumulator 22 is interposed between the pump 13 and the brake valve 26, and the hydraulic pressure generated by the pump 13 is constantly accumulated, so that the accumulated pressure of the accumulator 22 is released in an emergency. , Service brake 1 is activated.

The switching valve 23 is of a two-position switching type, in which a port is connected to a flow path from the parking brake valve 14, a b port is connected to a flow path from the accumulator 22, and a c port is connected to the brake chamber 12. Are connected.

The switching valve 23 is switched by operating the escape lever 27 in an emergency. When the lever 27 is not operated, the a port and the c port are communicated with each other, and when the lever 27 is operated, the b port and the c port are communicated with each other.

In the above configuration, when parking with the engine running, the parking brake lever 16 is operated. Then, the parking brake valve 14 is switched, and the hydraulic pressure supplied from the pump 13 to the brake chamber 12 is cut off. In the brake chamber 12, the piston rod 11 is shortened by the urging force of the spring 15 and the brake pad 9 is released. It is pressed against the rotating disk 8 and the parking brake 2 is applied.

Since the parking brake 2 is not applied while the vehicle is traveling, the hydraulic pressure from the pump 13 is supplied to the brake chamber 12 from the parking brake valve 14 via the switching valve 23. At this time, the piston rod 11 extends and the brake pad 9 is separated from the rotating disc 8. The hydraulic pressure from the pump 13 is stored in the accumulator 22.

If the engine stops due to some trouble, the hydraulic pressure is not supplied from the pump 13, so that the parking brake 2 is activated by the spring 15 and the vehicle cannot be moved. Will end up.

Therefore, when the emergency escape lever 27 is operated so that the vehicle can be towed, the switching valve 23 is switched, and the accumulator 22 and the brake chamber 12 communicate with each other. Then, the hydraulic pressure accumulated in the accumulator 22 is supplied to the brake chamber 12 via the switching valve 23. Due to this hydraulic pressure, the piston rod 11 extends, the brake pad 9 is separated from the rotary disk 8, the parking brake 2 is released, and the vehicle can be moved.

As described above, by using the accumulator mounted for the service brake, the parking brake can be temporarily released, so that the vehicle can be pulled and moved to a place where it does not interfere with traffic in an emergency. Secondary disasters can be prevented.

It should be noted that the present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made to the above embodiment within the scope of the present invention.

Although the parking brake of the present embodiment is arranged on the output shaft of the transmission, it is also applied to the parking brake arranged at the same position as the service brake or arranged between the propeller shaft and the differential. it can.

[0033]

[Effect of device]

 As is apparent from the above description, according to the present invention, the accumulator mounted for the service brake is connected to the spring chamber of the parking brake via the switching valve, so that the accumulator can be operated by operating the switching valve. The accumulated pressure can be used and the parking brake can be temporarily released. Therefore, the vehicle can be easily towed in an emergency.

Therefore, by using the existing accumulator, it is possible to provide a mechanism for temporarily releasing the parking brake with a simple configuration in which the switching valve is added.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a brake device showing an embodiment of the present invention.

FIG. 2 is a layout view of brakes in a vehicle

FIG. 3 is a hydraulic circuit diagram of a conventional parking brake.

[Explanation of symbols]

 1 Service Brake 2 Parking Brake 12 Spring Chamber 13 Pump 14 Parking Brake Valve 16 Parking Brake Lever 22 Accumulator 23 Switching Valve 27 Emergency Escape Lever

Claims (1)

[Scope of utility model registration request] 1. A parking brake for braking a wheel, an operating body for operating the parking brake by switching fluid pressure, an urging body for urging the operating body in the parking brake braking direction, and a fluid pressure for the operating body. And a fluid pressure supply means for keeping the parking brake in a non-braking state against the urging body, and an accumulator for accumulating the fluid pressure to operate the service brake is connected to the operating body. A parking brake releasing device for a vehicle, comprising a switching valve for switching between a flow path to the operating body and a flow path from the fluid pressure supply means to the operating body.