JPS5836614Y2 - Power brake device for vehicles - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a multi-system power brake system for a vehicle that is operated by switching automatic switching valves.

Conventionally, as shown in FIG. 1, in an automatically driven vehicle, when an automatic switching valve A is switched in response to a brake activation signal, compressed air accumulated in a pneumatic pressure source B is supplied to an air master cylinder C. There are two systems of braking systems that actuate the brakes by guiding the pressure oil converted into hydraulic pressure to the brake cylinder E in the wheel section. ■ Even if one system breaks down, the brakes can be applied by the other system's brake system. There is something that works.

However, such a device has the disadvantage that if one system breaks down, the braking force decreases by one system, increasing the braking distance, which is dangerous.

This idea is based on a multi-system power brake system for vehicles, in which each system is set to provide sufficient braking force to the vehicle, and each brake system has a mechanism that closes the fluid passage when the deceleration of the vehicle exceeds a predetermined value. By providing a speed control valve, the drawbacks of the conventional system are overcome and a predetermined braking force can be obtained even if one system fails.

An embodiment of this invention will be described below with reference to FIG.

The air pressure source 1a includes a brake cylinder 3a of the wheel section 2, a pressure reducing valve 4, a weak brake automatic switching valve 5a, and a deceleration control valve 6.
a, a shuttle valve 7, and an air master cylinder 8.

Further, between the air pressure source 1a and the shuttle valve 7, a strong braking automatic switching valve 5b and a deceleration control valve 6b are connected.
Pressure valve 4, weak brake automatic switching valve 5a, deceleration control valve 6
It is connected in parallel with a.

In addition, a pneumatic source 1 of the other system different from the pneumatic source 1a
b is also connected to the brake cylinder 3b of this system in exactly the same manner as above.

The air pressure sources 1a, lb are filled with compressed air supplied from an air compressor (not shown) driven by a dedicated motor or a travel motor so as to maintain a predetermined pressure at all times.

The broken pressure reducing valve 4 detects the inlet pressure and the outlet pressure, opens and closes the valve, and reduces the pressure so that the pressure difference becomes constant.

Further, the weak brake automatic switching valve 5a is switched to position a when the solenoid is energized without operating the brake.
When the air from the air pressure sources 1a and 1b is cut off, the air pressure chamber 8a of the air master cylinder 8 is communicated with the atmosphere, and when the solenoid is demagnetized by the weak brake activation signal, It is switched to position b, and compressed air from the air pressure sources 1a and 1b is supplied to the air pressure chamber 8a of the air master cylinder 8 via the deceleration control valve 6at and the shuttle valve 1.

In the past, the strong brake automatic switching valve 5b was switched to position a when the solenoid was energized without operating the brake.
The button is pressed to shut off the air from the air pressure sources 1a and Ib and to communicate the air pressure chamber 8a of the air master cylinder 8 with the atmosphere. When the solenoid is demagnetized by the strong brake activation signal, it moves to position b. switched, air sources 1a, 1b
The compressed air is supplied to the air pressure chamber 8a of the air master cylinder 8 via the deceleration fi1m valve 6b and the shuttle valve 7.

The deceleration control valve 6a is attached to the vehicle so as to be inclined with respect to the horizontal plane, and when the deceleration of the vehicle reaches a value set as a weak brake, the ball 6c climbs the slope 6d, and the automatic switching valve 5a and the air master cylinder 8, the fluid passage 9a is closed.

Deceleration again! The I-leg valve 6b is attached to the vehicle at a steeper angle than the deceleration control valve 6a, and closes the fluid passage 9b in the same manner as the deceleration control valve 6a when the deceleration of the vehicle reaches a value set for strong braking. It has become.

When compressed air is supplied through the deceleration control valve 6a, the enclosed shuttle valve 7 moves the ball 7a to communicate the deceleration control valve 6a and the pneumatic chamber 8a, and also connects the deceleration control valve 6b to the pneumatic chamber 8a. When the pressure chamber 8a is shut off and compressed air is supplied via the deceleration control valve 6b, the ball 7a is moved,
The deceleration control valve 6b and the pneumatic chamber 8a are communicated with each other, and the deceleration control valve 6a and the pneumatic chamber 8a are cut off.

The air master cylinder 8a in the housing increases and converts air pressure into hydraulic pressure, and when compressed air is supplied to the air pressure chamber 8a, the air pressure piston gbfF? and the hydraulic piston 8c that moves together therewith are moved against the spring 8d to open the hydraulic chamber 8e.
Pressure oil is supplied to the brake cylinders 3a and 3b of the wheel portion 2 to operate the brakes.

The brake cylinders 3a and 3b are configured so that the brake can be operated no matter which cylinder is supplied with pressure oil.

In each of the brake systems configured as described above, for example, whether it is a weak brake for general stationary stopping or a strong brake used in the past to prevent rear-end collisions between vehicles, when the other brake system fails, The setting is such that sufficient braking force can be obtained from only one system without causing the wheels to slip, ensuring safety in the event of a failure in other systems.

In this example, there are two brake systems, but more brake systems may be used.Although air and oil were used as the working fluids in the case, it is also possible to use only one of these fluids. It can also be a full air brake or a hydraulic full power brake.

Alternatively, instead of the ball valve type control valve described above, the deceleration control valve may be configured to electrically differentiate the rotational speed of the wheels, etc., detect the deceleration of the vehicle, and close the fluid passage at a predetermined deceleration. good.

In fact, the brake cylinders of each brake system do not need to be provided on all wheels, and the brake systems can be arranged separately, such as on the front wheels or the rear wheels.

Next, the operation of the vehicle power brake system configured as described above will be explained. First, the weak brake automatic switching valve 5a is shifted from the a position to the b position by a weak brake activation signal used for normal vehicle stopping. Switchable pneumatic source 1a
The compressed air of Pressure oil 8e is supplied to the brake cylinder 3a to operate the brake.

Similarly, in the other system, the air master cylinder 8 is actuated by the compressed air from the pneumatic pressure source 1b, and the brake cylinder 3b similarly performs the braking operation.

In this way, when the vehicle traveling in the direction of the arrow reaches a predetermined deceleration, the ball 6c of the deceleration control valve 6a climbs the slope 6d and closes the fluid passage 9a, and the vehicle stops if the deceleration exceeds this point. to prevent

When performing an emergency stop (sudden braking), the strong brake automatic switching valve 5b is switched from the a position to the b position by the strong brake activation signal, and the deceleration is increased to 1, which is a larger deceleration than the weak brake. Since the control valve 6b is open, the vehicle can be stopped with a large deceleration.

Furthermore, if the system on the pneumatic source 1b side breaks down for some reason and the brake cylinder 3b stops operating, for example, if the weak brake automatic switching valve 5a is switched from the a position to the b position by a brake activation signal, the same as described above can be applied. Then, the brake cylinder 3a is activated.

In this case, the brake cylinder 3a is pressed with a stronger pressure than in the normal case, and the deceleration control valve 6a closes at the point when the same braking force as when the brake cylinders 3a and 3b are working together is obtained. Even if the button is pressed in this case, the desired deceleration can be obtained and the braking distance will not become long.

As mentioned above, the vehicle power brake system of this invention is:
Even if the system fails, the vehicle can be stopped at a predetermined deceleration, and the braking distance is not increased, resulting in safety.

Additionally, since this invention uses a deceleration control valve, the vehicle will be stopped at a predetermined deceleration even if the vehicle load changes or the running resistance fluctuates due to wind, tire pressure, etc. can be done.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional power brake device for a vehicle, and FIG. 2 is an explanatory diagram showing an embodiment of the power brake device for a vehicle of this invention. 1a, lb...Air pressure source, 3a, 3b...Brake cylinder, 5a, 5b...Automatic switching valve, 6a, 6b...
- Deceleration control valve, 8...Air master cylinder, 9a. 9b...Fluid passage.

Claims (1)

[Scope of utility model registration request] A brake cylinder provided in the wheel portion, a fluid pressure source that supplies working fluid to the brake cylinder, a working fluid passage that communicates these brake cylinders and the fluid pressure source, and a brake cylinder disposed in the working fluid passage that receives a brake activation signal. A brake system including an automatic switching valve that opens the passage in accordance with the operating fluid passage, and a deceleration control valve that is disposed in the working fluid passage and closes the passage when the deceleration of the vehicle exceeds a predetermined value is provided independently from each other. A power brake device for a vehicle characterized by being equipped with a system.