JPH0435382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a fluid pressure operated check valve used in a brake operating device of an automobile, and in particular allows a free flow of brake operating fluid at all times, while The present invention relates to a fluid pressure operated check valve which functions as a check valve when a signal pressure is introduced, and which automatically opens when a backflow pressure of a predetermined pressure or higher is applied.

b. Conventional technology In large vehicles such as trucks and trailers,
A brake valve is attached to the brake pedal, and when the brake pedal is depressed, compressed air from the air tank is supplied to the brake actuator via the brake valve, and the hydraulic pressure generated by the brake actuator is supplied to the brake pedal. The brake is supplied to the cylinder to operate the brake.

c Problems to be solved by the invention Regarding the conventional brake operating device described above,
When the brake pedal is released, the brake is released, so if the vehicle is temporarily stopped on a slope, etc., it is necessary to perform operations such as pulling the handbrake each time, and when starting on a slope, the handbrake must be released. Very skilled operations such as operating the accelerator and clutch were required.
As a result, driving operations are complicated, and there is a risk that the engine stalls or the vehicle backs up when starting on an uphill road.

The present invention has been devised to effectively solve the above-mentioned problems, and its purpose is to automatically apply the brakes even when the brake pedal is released after the vehicle has stopped, and to prevent the vehicle from starting. Sometimes the brakes are automatically released to allow a smooth start.

d Means for Solving the Problems In the fluid pressure operated check valve of the present invention, the valve is connected to the air tank or the atmosphere through the inlet connected to the brake control pressure control valve, the outlet connected to the brake actuator, and the switching valve. a cylinder having a selectively connected signal pressure port; a valve seat disposed in a fluid passageway between the inlet and the outlet; and a valve seat mounted in the direction of the valve seat by a first spring; a signal pressure chamber communicating with the signal pressure port; a signal pressure chamber communicating with the signal pressure port; defining an output pressure chamber communicating with the outlet, and biased by a second spring in a direction to contract the signal pressure chamber;
a piston assembly that is actuated by the pressure of the pressure source supplied to the signal pressure chamber and that makes the valve body and the valve seat contact each other to constitute a check valve mechanism; The assembly is disposed with one end facing the signal pressure chamber and the other end facing the atmospheric pressure chamber, and is moved within a predetermined range by the pressure of the signal pressure chamber to bring the valve body and the valve seat into contact. a signal piston having one end facing the output pressure chamber and the other end facing the atmospheric pressure chamber, and moved by the pressure of the output pressure chamber to separate the valve body and the valve seat. an output pressure sensitive piston, and a third valve disposed between the signal piston and the output pressure sensitive piston, and configured to set an operation start pressure of the output pressure sensitive piston.
It is composed of a spring and a spring.

e Function In the fluid-operated check valve of the present invention, when compressed air is not supplied to the signal pressure chamber, the brake operating fluid flows freely between the valve body and the valve seat, and compressed air flows into the signal pressure chamber. When supplied, the piston is actuated to establish a check valve mechanism between the inlet and the outlet. Therefore, while compressed air is being supplied to the signal pressure chamber, even if the operation of the brake control pressure control valve is released, the fluid acting on the brake actuator is prevented by the check valve mechanism. It stays there without being expelled. Further, the maximum pressure in the output pressure chamber at that time is determined by the biasing force of the third spring.

f Embodiment An embodiment in which the present invention is applied to a brake operating device for an automobile will be described below based on the drawings.

Figure 1 shows the schematic configuration of the brake operating device, in which 1 is an air tank, 2 is an air tank, and 2 is an air tank.
3 is a brake actuator, 3 is a brake control pressure control valve, 4 is a wheel cylinder, 5 is a fluid pressure operated check valve, 6 is a solenoid valve, and 7 is a controller. The pressure in the air tank 1 is supplied to the brake control pressure control valve 3 and the solenoid valve 6 via pipes 8 and 9.
It is now being supplied to

The discharge side of the brake control pressure control valve 3 is connected to a fluid pressure operated check valve 5 via a conduit 10,
When the brake pedal 11 is depressed, pressure is supplied to the fluid pressure operated check valve 5, and when the brake pedal 11 is released, the discharge side of the brake control pressure control valve 3 is configured to communicate with the atmosphere. On the other hand, the discharge side of the solenoid valve 6 is connected to the fluid pressure operated check valve 5 via a conduit 12, and when the solenoid valve 6 is ON, signal pressure is supplied to the pneumatic operation valve 5, and when the solenoid valve 6 is OFF. At this time, the discharge side of the solenoid valve 6 is configured to communicate with the atmosphere.

The controller 7 is configured to receive information regarding the operation status of the brake, accelerator, clutch, etc. and vehicle speed, and is configured to turn the solenoid valve 6 OFF when the vehicle is running or starting, and turn ON when the vehicle is stopped. There is.

The discharge side of the fluid pressure operated check valve 5 is connected to the brake actuator 2 via a conduit 13, and the brake actuator 2 is driven by the pressure supplied from the fluid pressure operated check valve 5. Then, hydraulic pressure is supplied to the wheel cylinder 4, and the brake shoe 14 is configured to perform a brake operation.

The fluid pressure operated check valve 5 is constructed as shown in FIGS. 2 and 3 in detail. That is, the fluid pressure operated check valve 5 includes a signal piston 18 disposed within the cylinder 17, an output pressure sensitive piston 19 disposed in front of the signal piston 18, and a piston 19 attached to the front end of the piston 19. Valve body 20
It has A signal pressure chamber 21 is formed behind the signal piston 18, and this signal pressure chamber 21 is connected to the discharge side of the electromagnetic valve 6 through the signal pressure port 27 through the aforementioned pipe 12. An atmospheric chamber 22 is formed between the signal piston 18 and the output pressure sensitive piston 19, and this atmospheric chamber 22 is communicated with the atmosphere through a communication hole 23. The output pressure chamber 24 in which the valve body 20 is disposed is connected to the brake actuator 2 via the outlet 26 and the above-mentioned pipe line 13, and the valve seat 25 is connected to the brake actuator 2 via the above-mentioned pipe line 10. It is connected to the pressure control valve 3.

A pressure setting spring 29 is disposed between the signal piston 18 and the piston output pressure sensor 19, and both pistons 18, 19 are urged away from each other by this spring 29. A support plate 30 and a stop ring 31 are attached to the output pressure sensitive piston 19, and the support plate 30 and the signal piston 18 are always in contact with each other. Further, the support plate 30 and the retaining ring 31 are normally in contact with each other as shown in FIG. 2, thereby restricting the mutual spacing between the pistons 18 and 19 from increasing.

A first stopper portion 3 is provided on the inner circumference of the cylinder 17.
2 and a second stopper part 33 are formed, and the pistons 18 and 19 are connected to these stopper parts 3.
2 and 33, the position is regulated to a predetermined forward movement position. The output pressure sensitive piston 19 is always urged in the backward direction by the return spring 34, and the valve body 20 is urged in the closing direction by the spring 35. Note that the valve body 20 is attached to the retaining ring 3.
6 and 37 to prevent it from coming off the output pressure sensitive piston 19.

The brake operating device is constructed as described above, and when the vehicle is running, the solenoid valve 6 is turned off, and atmospheric pressure is supplied to the signal pressure chamber 21 of the fluid pressure operated check valve 5 via the pipe 12. The signal piston 18, the output pressure sensitive piston 19, and the valve body 20 are integrally moved back by the return spring 34 as shown in FIG. 2, and the valve seat hole 25 is opened.

When the brake pedal 11 is depressed in this state, compressed air from the air tank 1 is supplied from the inlet 28 of the fluid pressure operated check valve 5 into the check valve 5 and passes between the valve body 20 and the valve seat 25. It then reaches the outlet 26 and is further supplied to the brake actuator 2, causing the brake shoe 14 to perform a brake operation. Furthermore, when the brake pedal 11 is released, the compressed air in the brake actuator 2 is exhausted to the outside from the exhaust port (not shown) of the brake control pressure control valve 3, and the brake shoe 14 operates to release the brake.

Next, when the vehicle stops, this state is sensed by the controller 7, and the solenoid valve 6 is turned on after one second, for example.
be made into When the solenoid valve 6 is turned on, compressed air is introduced into the signal pressure chamber 21 of the fluid pressure operated check valve 5 via the pipes 9 and 12. As a result, the signal piston 18 moves forward in the right direction as shown in FIG. 3 due to the pressure in the signal pressure chamber 21, comes into contact with the first stopper portion 32, and stops. In addition, the output pressure sensitive piston 19
While being pressed by the spring 29, it moves forward in the right direction against the return spring 34, as shown in FIG. 3, and comes into contact with the second stopper portion 33 and stops. Then, the valve body 20 is pressed against the valve seat 25 by the biasing force of the spring 35 to close it. Therefore, the compressed air inside the brake actuator 2 is maintained as it is, and the brake shoe 14 continues to operate the brake. For this reason, if you temporarily stop on a slope etc. and press the brake pedal
Even if 1 is released, there is no risk that the vehicle will start moving on its own, and there is no need to worry about pulling the handbrake every time.

In addition, in this stopped state, brake pedal 1
1 again, the inlet 28 and output pressure chamber 24
Due to the pressure difference between the brake actuator and the brake actuator, only the valve body 20 moves to the left in FIG. 3 against the spring 35, opening the valve seat 25 and replenishing the brake actuator 2 with compressed air. Therefore, a desired braking force can be easily obtained depending on the degree of inclination of the slope or the like.

Next, when the vehicle is prepared to start by operating the accelerator, clutch, etc., the controller 7 senses this and turns the solenoid valve 6 OFF. Solenoid valve 6 is OFF
Then, the compressed air in the signal pressure chamber 21 of the fluid pressure operated check valve 5 is discharged via the electromagnetic valve 6, so the check valve 5 returns to the state shown in FIG. 2. If the brake pedal 11 is released at this time, the compressed air in the brake actuator 2 will be exhausted to the outside from the exhaust port of the brake control pressure control valve 3, and the brake shoe 14 will release the brake, making it possible to start. Become. Therefore, especially when starting up an uphill road, there is no need for skilled operations, such as the conventional method of loosening the handbrake and operating the accelerator or clutch, and it is possible to start smoothly without stalling the engine or moving the vehicle backwards. .

In addition to the above-mentioned features, the brake operating device according to the present invention also has the feature that the magnitude of the maximum braking force when the vehicle is stopped is not affected even if the pressure in the air tank 1 fluctuates. That is, a compressor (not shown) that supplies compressed air to the air tank 1 is activated when the pressure within the air tank 1 becomes lower than a predetermined pressure, and is stopped when the pressure within the air tank 1 becomes higher than a predetermined pressure. .
Therefore, the pressure within the air tank 1 repeatedly fluctuates within a predetermined range under normal conditions. This fluctuating pressure is applied to the fluid pressure operated check valve 5 when the vehicle is stopped.
The signal piston 1 is introduced into the signal pressure chamber 21 of the signal piston 1.
8 is regulated in position by a first stopper portion 32 to a predetermined forward movement position. Therefore, in FIG. 3, the only rightward force acting on the output pressure sensitive piston 19 is the force of the spring 29, and the maximum pressure within the output pressure chamber 24 is determined by the spring 29. Specifically, considering the state in which the output pressure sensitive piston 19 has moved to the left by a distance x and the retaining rings 36 and 37 are in contact with each other in FIG. 3, F+kx=P _p A _p F: Setting of the spring 29 force, k: spring constant of the spring 29, P _p : maximum pressure in the output pressure chamber 24, A _p : pressure receiving area of the output pressure sensitive piston 19. When the pressure inside the output pressure chamber 24 becomes greater than P _p , the output pressure sensitive piston 19 moves further to the left than this state, the valve seat 25 opens, and the excess pressure inside the output pressure chamber 24 is released. The air is exhausted from the exhaust port of the brake control pressure control valve 3. Then, when the pressure inside the output pressure chamber 24 decreases to P _p , the valve seat 25 is closed again.

In this way, the maximum pressure P _p in the output pressure chamber 24 is maintained at a predetermined level by the spring 29 regardless of the level of the pressure supplied to the signal pressure chamber 21 . The maximum pressure of compressed air supplied or the maximum oil pressure supplied to the wheel cylinder 4 can be kept constant, and the maximum braking force can be kept constant.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be modified in various ways. For example, in the above embodiment, the fluid pressure operated check valve 5 and the electromagnetic valve 6 are constructed as separate bodies, but they may be constructed as an integrated unit.

Note that it is not inconceivable that the above-mentioned fluid pressure operated check valve 5 be installed in the hydraulic pressure supply system for the wheel cylinder 4, but in this case, the high pressure held in the wheel cylinder 4 when the vehicle is stopped is It is conceivable that the brake fluid momentarily flows back into the oil reservoir system when the brake is released when the vehicle is started, which may cause a problem with pressure resistance in the oil reservoir system.

f. Effects of the Invention As described above, the present invention uses the signal pressure introduced into the signal pressure chamber to move the piston supporting the valve body forward to close the space between the inlet and the outlet.
When no signal pressure is introduced into the signal pressure chamber, free flow of fluid is allowed and normal brake operation can be performed, and when signal pressure is introduced into the signal pressure chamber, reverse flow of brake operating fluid is allowed. As a result, a constant braking force can be maintained even when the brake pedal is released. In addition, since the output pressure sensitive piston that supports the valve body is balanced with the pressure in the output pressure chamber by the force of the spring,
The maximum pressure in the output pressure chamber can be kept constant regardless of fluctuations in the signal pressure introduced into the signal pressure chamber, and the operating characteristics of the fluid pressure operated check valve can be kept constant.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic configuration diagram of a brake operating device, Fig. 2 is a longitudinal sectional view of a fluid pressure operated check valve during traveling and starting, and Fig. FIG. 3 is a sectional view similar to FIG. 2 when the vehicle is stopped. 1... Air tank, 2... Brake actuator, 3... Brake control pressure control valve, 4
...Foil cylinder, 5...Fluid pressure operated check valve,
6... Solenoid valve, 7... Controller, 11... Brake pedal, 14... Brake shoe, 17...
... Cylinder, 18 ... Signal piston, 19 ... Output pressure sensitive piston, 20 ... Valve body, 21 ... Signal pressure chamber, 24 ... Output pressure chamber, 25 ... Valve seat, 27 ...
...Signal pressure port, 28...Inlet, 29...Spring, 32
...first stopper section, 33...second stopper section, 35...spring.

Claims (1)

[Claims] 1. An inlet connected to a brake control pressure control valve, an outlet connected to a brake actuator, and a signal pressure port selectively connected to an air tank or the atmosphere via a switching valve. a cylinder; a valve seat disposed in a fluid passageway between the inlet and the outlet; the valve seat being biased toward the valve seat by a first spring and maintained at a constant distance from the valve seat; , a valve body disposed opposite to the valve seat on the outlet side with respect to the valve seat; defining a signal pressure chamber communicating with the signal pressure port and an output pressure chamber communicating with the outlet; , is biased by a second spring in a direction to contract the signal pressure chamber, is actuated by the pressure of the air tank supplied to the signal pressure chamber, and is brought into contact with the valve body and the valve seat. a piston assembly that constitutes a check valve mechanism, the piston assembly being disposed such that one end faces the signal pressure chamber and the other end faces the atmospheric pressure chamber, and the piston assembly is arranged such that one end faces the signal pressure chamber and the other end faces the atmospheric pressure chamber. a signal piston that is moved within a predetermined range by a signal piston and brought into contact with the valve body and the valve seat; an output pressure sensitive piston that is moved by the pressure in the chamber and separates the valve body and the valve seat; and an output pressure sensitive piston that is disposed between the signal piston and the output pressure sensitive piston and actuates the output pressure sensitive piston. A fluid pressure operated check valve comprising a third spring that sets a starting pressure.