JPH0872705A - Brake pressure control valve - Google Patents

Abstract

PURPOSE: To dispense with the need of the machining both of the pin for engaging an auxiliary piston with a main piston and of the pin hole for inserting the pin by engaging the end of a retainer with the auxiliary piston so that the amount of projection of the auxiliary piston can be regulated. CONSTITUTION: The base end 29a of a retainer 29 is held by a spring 25 to a main piston 22. The retainer 29 is of a cylindrical shape and the base end 29a thereof is provided with an outward flange, and also the forefront end 29b thereof is provided with an inwardly formed flange. The forefront end 29b is engaged with the flange 26a of an auxiliary piston 26 so that the auxiliary piston 26 is prevented from being coming off from the hole 22a of the main piston 22. On the other hand, a valve seat 30 is formed in the opening on the output pressure chamber 23 side of an input port 21a, and when the piston 22 is moved to the right, a valve body 27 is abutted on the valve seat 30 for closing the input port 21a. In that case, the main piston 22 is abutted on the stepped part 21d of a housing 21 so that the further movement thereof is regulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake pressure control valve, and more particularly to an improvement of a control valve used in a slope start assist device.

[0002]

2. Description of the Related Art In large vehicles such as trucks and trailers, a brake valve is attached to a brake pedal. In such a brake operating device, by depressing the brake pedal, compressed air in the air tank is supplied to the brake actuator via the brake valve, and the hydraulic pressure generated by the brake actuator is applied to the wheel cylinder, whereby the brake is applied. It is working. Then, when the brake pedal is released, the brake is released.

In the above-mentioned conventional brake operating device, when temporarily stopping on a slope or the like, it is necessary to operate such as pulling a side brake, and when starting on an uphill road, the side brake is applied. It required very skilled operation such as operating the accelerator and clutch while releasing. For this reason, the driving operation is complicated, and there is a risk that the engine stalls or the vehicle retreats when starting on an uphill road.

Therefore, the applicant first provided a brake operating device which solved the above-mentioned problems (Japanese Patent Publication No. 6-45334).
(See the official gazette).

In this brake operating device, as shown in FIG. 3, when the brake pedal 1a is depressed, the brake valve 1 enters the supply mode, and the compressed air in the air tank 2a passes through the brake valve 1 and the conduit 7a. Fluid pressure operation check valve) 10 is supplied to the input port 10a,
It is supplied to the brake actuator 3 from the output port 10b via the output pressure chamber 11 of the brake pressure control valve 10 shown in FIG. Then, the brake actuator 3 is operated, and the working fluid is supplied to the wheel cylinder 4 via the pipe 7c. Further, when the brake pedal 1a is released, the brake valve 1 is placed in the exhaust mode, and the compressed air in the brake actuator 3 is transferred to the pipeline 7b and the brake pressure control valve 1
0, through the pipe line 7a, and exhausted from the exhaust port 1b of the brake valve 1 to the outside. Therefore, the brake is released. Such operation is no different from that of the conventional brake operating device.

In this brake operating device, when the brake pedal 1a is continuously depressed while the vehicle is stopped, this state is detected by the controller 5, and the solenoid valve 6 is activated after a predetermined time (for example, 1 second) has elapsed. The compressed air in the air tank 2b is introduced into the signal pressure chamber 12 of the brake pressure control valve 10 shown in FIG. The compressed air urges the piston 14 having the valve body 13 in the brake pressure control valve 10. As a result, the piston 14
Is moved to the right by the pressure of the signal pressure chamber 12 against the urging force of the spring 16 as shown in FIG.
Is closed by the valve body 13. Therefore, the compressed air inside the brake actuator 3 is retained as it is, and the brake operating state is maintained.

Therefore, even if the vehicle is temporarily stopped on a slope or the like and the brake pedal 1a is released, the vehicle does not start to move naturally, and the trouble of pulling the side brakes one by one is eliminated. When the brake pedal 1a is strongly depressed again in the stopped state shown in FIG. 6, only the valve body 13 is moved by the pressure in the input port 10a to open the input port 10a, and the brake actuator 3 is replenished with compressed air. To be done. Therefore, a desired braking force according to the degree of inclination of a slope or the like can be easily obtained. Further, the pressure of the output pressure chamber 11 is balanced with the pressure of the signal pressure chamber 12 and is maintained at a relatively low pressure (for example, ⅓ to ¼ of the maximum brake pressure), so that the brake is operated for a long time. Even in the state, the pipeline 7
Unreasonable pressure does not act on b, 7c, etc., and the durability can be improved.

When the vehicle is ready to start by operating the accelerator, clutch, etc., the controller 5 detects this and demagnetizes the solenoid valve 6. Then, the compressed air in the signal pressure chamber 12 is discharged from the exhaust port 6a to the outside, and the piston 14 is returned to the original state by the urging force of the spring 16 accordingly. At this time, if the brake pedal 1a is released, the compressed air in the brake actuator 3 is exhausted to the outside from the exhaust port 1b of the brake valve 1, the brake is released, and the vehicle can start. Therefore, particularly when starting on an uphill road, it is not necessary to perform a skilled operation such as operating an accelerator or a clutch while loosening a side brake as in the conventional case, and a smooth start is possible without causing a stall or a vehicle retreat.

[0009]

By the way, in the above brake pressure control valve 10, as shown in FIG. 4, the auxiliary piston 17 is disposed in the piston 14 so as to be retractable, and the valve is provided at the tip of the auxiliary piston 17. The body 13 is arranged, and the spring 18 is interposed between the piston 14 and the auxiliary piston 17 to urge the auxiliary piston 17 toward the valve seat 15 so that the auxiliary piston 17 does not drop from the piston 14. And to prevent the pin 14a from slipping out of the piston 14 by engaging the auxiliary piston 17 with the piston 14 by the pin 14a so that the valve body 13 also returns with the piston 14 when the piston 14 returns. In addition, the retainer 19 closes the pin hole 14b. Therefore, the structure is complicated and the processing is complicated.

Therefore, an object of the present invention is to provide a brake pressure control valve having a simple structure.

[0011]

According to the brake pressure control valve of the present invention, an input port connected to the brake valve, an output port connected to the brake actuator, and a switching valve are selectively connected to the air tank or the atmosphere. A valve housing having a signal pressure port, a valve seat arranged in a fluid passage between the input port and the output port, and a first spring urged toward the valve seat, At a time, a certain distance from the valve seat is maintained, and a valve element disposed opposite the valve seat on the output port side of the valve seat and a signal pressure communicating with the signal pressure port in the valve housing. A chamber and an output pressure chamber communicating with the output port, and is urged by a second spring in a direction to reduce the signal pressure chamber,
A brake pressure control valve comprising: a main piston that is operated by the pressure of the air tank supplied to the signal pressure chamber and that constitutes the check valve mechanism by bringing the valve element into contact with the valve seat. A hole that is opened at the tip end surface of the auxiliary piston, the auxiliary piston is removably inserted into the hole, the valve body is disposed at the tip of the auxiliary piston, and the first spring is used to support the auxiliary spring. It is arranged between the piston and the main piston, and further, the base end of the tubular retainer is supported by the main piston by the second spring, and the tip of the retainer is engaged with the auxiliary piston. , The amount of protrusion of the auxiliary piston is regulated.

[0012]

In the brake pressure control valve of the present invention, a pin for engaging the auxiliary piston with the main piston is not required, and a pin hole for inserting the pin is not required.

[0013]

1 and 2 show a brake pressure control valve according to the present invention.

An input port 21a, an output port 21b and a signal pressure port 21c are formed in the housing 21 of the brake pressure control valve 20. A main piston 22 is arranged in the housing 21, and the piston 22 is divided into an output pressure chamber 23 and a signal pressure chamber 24. The input port 21a and the output port 21b are open to the output pressure chamber 23.

The main piston 22 is urged by a spring 25 provided in the output pressure chamber 23 in a direction to reduce the signal pressure chamber 24. Further, the main piston 22 is formed with a hole 22a opening at its front end.
The auxiliary piston 26 is fitted in a.

The auxiliary piston 26 has a valve body 27 at its tip and a flange 26a on its front peripheral surface. And
The auxiliary piston 26 is urged toward the input port 21a by a spring 28 arranged in the hole 22a.

A base end 29a of a retainer 29 is held by the spring 25 on the main piston 22. The retainer 29 has a tubular shape, and an outward flange is formed on the base end 29a and an inward flange is formed on the tip end 29b. The tip 29b is engaged with the flange 26a of the auxiliary piston 26, thereby preventing the auxiliary piston 26 from falling out of the hole 22a of the main piston 22.

On the other hand, a valve seat 30 is formed at the opening of the input port 21a on the output pressure chamber 23 side, and when the piston 22 is moved to the right, as shown in FIG. Contacts the valve seat 30 and closes the input port 21a. At this time, the main piston 22 is connected to the step portion 21d of the housing 21.
, And further movement is restricted.

The brake pressure control valve 20 includes a solenoid valve 4
0 is attached. In this electromagnetic valve 40, valve chambers 42 and 43 are formed below a plunger 41, and these valve chambers 42 and 43 are connected to each other by a passage 44.
Valve bodies 45 and 46 are arranged in the valve chambers 42 and 43, respectively, and these valve bodies 45 and 46 are connected to each other by a rod 47a. Further, the valve body 45,
46 is connected to the plunger 41 via a rod 47b. Then, when the plunger 41 moves up and down, a pair of valve seats 48, 49 formed at both upper and lower ends of the passage 44.
The valve bodies 45 and 46 are configured to come into contact with and separate from each other. The valve bodies 45 and 46 are urged upward by a spring 50 in FIG.

The valve chamber 43 communicates with the pressure introducing port 51, and the intermediate portion of the passage 44 communicates with the signal pressure chamber 24 of the brake pressure control valve 20 via the signal pressure port 21c. The valve chamber 42 communicates with the exhaust port 53 via a passage 52. The atmosphere chamber 31 of the brake pressure control valve 20
Are communicated with the valve chamber 42 via a passage 52.

As shown in FIG. 3, the input port 21a of the brake pressure control valve 20 is connected to the output port 1c of the brake valve 1 via the conduit 7a, and the output port 21b is connected to the conduit. It is connected to the input port 3a of the brake actuator 3 via 7b. Further, the pressure introduction port 51 of the solenoid valve 40 is connected to the air tank 2b via the conduit 7d.
Is connected to.

The brake pressure control valve 20 is constructed as described above, the solenoid 54 of the solenoid valve 40 is demagnetized when the vehicle is running, and the pair of valve bodies 45 and 46 are springs 50 as shown in FIG. It has been pushed upwards. Therefore, the upper valve body 45 is separated from the valve seat 48 and abuts on the valve seat 49 of the lower valve body 46. Therefore, compressed air is not introduced into the signal pressure chamber 24 of the brake pressure control valve 20, the piston 22 is returned by the return spring 25 as shown in FIG. The mouth 21a is open.

When the brake pedal 1a of the brake valve 1 is stepped on in this state, the brake valve 1 enters the supply mode, and compressed air is supplied to the input port 21a of the brake pressure control valve 20 via the brake valve 1. This compressed air is discharged from the output port 21b through the output pressure chamber 23, is supplied to the brake actuator 3, and operates the brake actuator 3. Then, the brake actuator 3 generates a working fluid corresponding to the pressure of the compressed air, and the wheel cylinder 4 is operated by the pressure of the fluid. Further, when the brake pedal 1a is released, the brake valve 1 enters the exhaust mode, and the compressed air in the brake actuator 3 is discharged to the outside from the exhaust port 1b of the brake valve 1 via the brake pressure control valve 20. Therefore, the hydraulic pressure acting on the wheel cylinder 4 disappears and the brake is released.

Next, when the brake pedal 1a is continuously depressed while the vehicle is stopped, this state is detected by the controller 5, and the solenoid valve 40 is detected after a lapse of a predetermined time (for example, 1 second).
The solenoid 54 is excited. When the solenoid 54 is excited, the plunger 41 moves downward as shown in FIG. 2 against the biasing force of the spring 50, the valve element 45 contacts the upper valve seat 48, and the valve element 46 moves downward. It is separated from the valve seat hole 49 on the side. Therefore, compressed air is introduced into the signal pressure chamber 24 of the brake pressure control valve 20 via the signal pressure port 21c. As a result, the main piston 22 is moved to the right by the pressure of the signal pressure chamber 24 against the biasing force of the spring 25 as shown in FIG. The mouth 21a is closed. Therefore, the compressed air inside the brake actuator 3 is retained as it is, and the wheel cylinder 4 continues the brake operation.
Therefore, even if the vehicle is temporarily stopped on a slope or the like and the brake pedal 1a is released, the vehicle does not start to move naturally, and there is no need to bother pulling the side brakes.

When the brake pedal 1a is strongly depressed again in the stopped state shown in FIG. 2, the auxiliary piston 26 moves to the left against the urging force of the spring 28 due to the pressure in the input port 21a, and the valve The body 27 moves away from the valve seat 30, and the brake actuator 3 is replenished with compressed air. Therefore, a desired braking force according to the degree of inclination of a slope or the like can be easily obtained. Along with that, the piston 22 is returned to the original position by the urging force of the spring 25. Then, the pressure in the output pressure chamber 23 balances with the pressure in the signal pressure chamber 24 and is relatively low (for example, 1 / maximum of the maximum brake pressure).
Since it is held at 3 to 1/4), even if the brake is operated for a long period of time, an excessive pressure does not act on the pipe line 7b or the like, and the durability thereof can be improved.

Next, when the vehicle is ready to start by operating the accelerator, the clutch or the like, the controller 5 senses this and the solenoid 54 of the solenoid valve 40 is demagnetized. When the solenoid 54 is demagnetized, the valve bodies 45 and 46 are moved upward by the urging force of the spring 50, the valve body 45 separates from the valve seat 48, and the valve body 46 moves away from the valve seat 46, as shown in FIG. Four
Contact 9 Therefore, the compressed air in the signal pressure chamber 24 of the brake pressure control valve 20 is supplied to the signal pressure port 21c, the passage 44,
It is discharged to the outside through the valve chamber 42, the passage 52, and the exhaust port 53. Along with that, the piston 22 is returned to the original position by the urging force of the spring 25. Then, the compressed air in the brake actuator 3 is discharged to the outside from the exhaust port 1b of the brake valve 1, the brake is released, and the vehicle can start. Therefore, particularly when starting on an uphill road, it is not necessary to perform a skilled operation such as operating an accelerator or a clutch while loosening a side brake as in the conventional case, and a smooth start is possible without causing a stall or a vehicle retreat.

[0027]

As described above, in the brake pressure control valve according to the present invention, the tip of the retainer is engaged with the auxiliary piston to regulate the movement of the auxiliary piston within a certain range. That is, the brake pressure control valve according to the present invention does not require a pin for engaging the auxiliary piston with the main piston, which has been conventionally used, and does not require processing of a pin hole for inserting the pin. Therefore, the structure is simple,
Processing becomes easy and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a non-actuated state of a brake pressure control valve according to the present invention.

2 is a cross-sectional view showing an operating state of the brake pressure control valve shown in FIG.

FIG. 3 is a piping diagram conceptually showing a brake operating device.

FIG. 4 is a cross-sectional view showing a non-actuated state of a conventional brake pressure control valve.

5 is a cross-sectional view showing an operating state of the brake pressure control valve shown in FIG.

[Explanation of symbols]

 1 Brake valve 2b Air tank 3 Brake actuator 6 Switching valve 7a, 7b, 7d Pipe line 20 Brake pressure control valve 21 Valve housing 21a Input port 21b Output port 21c Signal pressure port 22 Main piston 22a hole 23 Output pressure chamber 24 Signal pressure chamber 25 Spring 26 Auxiliary piston 26a Flange 27 Valve body 28 Spring 29 Retainer 29a Base end 29b Tip 30 Valve seat 40 Solenoid valve

Claims (1)

[Claims] 1. A valve housing having (a) an input port connected to a brake valve, an output port connected to a brake actuator, and a signal pressure port selectively connected to an air tank or the atmosphere through a switching valve, (B) a valve seat arranged in a fluid passage between the input port and the output port, and (c) is urged in the direction of the valve seat by a first spring to normally move from the valve seat. A valve body which is arranged at a certain distance and faces the output port with respect to the valve seat so as to face the valve seat, and (d) a signal pressure chamber which communicates the inside of the valve housing with the signal pressure port. The output pressure chamber communicates with the output port, and is urged by the second spring in a direction to reduce the signal pressure chamber, and is operated by the pressure of the air tank supplied to the signal pressure chamber, Touch the valve body to the valve seat. In the brake pressure control valve including a main piston that constitutes a check valve mechanism, (e) a hole is formed in the tip surface of the piston, and the auxiliary piston is removably inserted into the hole. The auxiliary piston, the valve body is arranged at the tip of the auxiliary piston, the first spring is arranged between the auxiliary piston and the main piston, and the base end of the tubular retainer is arranged at the first end. A brake pressure control valve, characterized in that the spring is supported on the piston by a second spring, and the tip of the retainer is engaged with the auxiliary piston to restrict the protrusion amount of the auxiliary piston.