JPH1111271A - Brake pressure control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhaust compressed air from a brake pressure control valve securely even if an exterior exhaust pipeline for exhausting compressed air led into a signal pressure chamber of a piston is closed when a brake is released. SOLUTION: In the brake pressure control valve 20 of a brake operating device, a communicating path 23 communicated to an exhaust port or an air chamber 24 is provided in the housing 21 of the control valve 20, and also a check valve 27 which allows only a flow from the communicating path 23 or air chamber 24 to an input port 10a side is arranged between the communicating path 23 or air chamber 24 and the input port side 10a including a pipeline 6a connected to a brake valve. By this, even if an exterior pipeline connected to the exhaust port is closed by icing in winter, compressed air led into the signal pressure chamber 12 is released to the atmosphere through the check valve 27 so as to prevent a brake dragging event from occurring after the release of a brake.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a brake pressure control valve which is used in a hill start assist device or the like and controls a check of compressed air supplied from an air tank to a brake actuator.

[0002]

2. Description of the Related Art In large vehicles such as trucks and trailers, a brake valve is attached to a brake pedal as a brake operating device. In such a brake operating device, when the brake pedal is depressed, the 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. The brake is operating. And
Releasing the brake pedal releases the brake.

In the conventional brake operating device as described above, when the vehicle is temporarily stopped on a slope or the like, it is necessary to apply an operation such as applying a side brake, and when starting on an uphill road, the side brake is required. Extremely skilled operation such as operating the accelerator and clutch while releasing the brake was required. For this reason, the driving operation is complicated, and there is a possibility that the engine stalls or the vehicle retreats when starting on an uphill road.

[0004] Therefore, the applicant has previously provided a brake operating device which solves the above problem (Japanese Patent Publication No. 6-45334).
Reference).

That is, in this brake operating device, as shown in the system diagram of FIG. 3, when the brake pedal 1a is depressed, the brake valve 1 enters the supply mode, and the brake valve 1 and the air tank 2a are connected via the pipe 6a. Compressed air is supplied to an input port 10a of a brake pressure control valve (fluid pressure operated check valve) 10 and is connected to an output port 10b through an output pressure chamber 11 of the brake pressure control valve 10 as shown in the sectional view of FIG. It is supplied to the brake actuator 3 via the road 6b. Then, the brake actuator 3 operates and the working fluid is supplied to the wheel cylinder 4 via the pipe 6c. When the brake pedal 1a is released, the brake valve 1 enters the exhaust mode, and the brake actuator 3
The compressed air inside is discharged to the outside from the exhaust port 1b of the brake valve 1 via the pipe 6b, the brake pressure control valve 10, and the pipe 6a. Therefore, the brake is released. Such an operation is no different from the conventional brake operation device.

On the other hand, in this brake operating device, if the brake pedal 1a is continuously depressed in a state where the vehicle is stopped, this state is sensed by the controller 7, and after a lapse of a predetermined time (for example, one second), the electromagnetic switching valve 5 Is excited, and the signal pressure port 10f of the brake pressure control valve 10 shown in FIGS.
Then, the compressed air in the air tank 2b is introduced into the signal pressure chamber 12 via the conduit 6d. The piston 14 having the valve element 13 in the brake pressure control valve 10 is urged by the compressed air. The piston 14 has an enlarged diameter portion 14a and is slidably disposed in the control valve 10.

As a result, the piston 14 is moved by the pressure of the signal pressure chamber 12 as shown in an enlarged view of FIG.
It is moved against the urging force of 5. And the piston 1
4 stops when the enlarged diameter portion 14a contacts the step portion 10c. In this state, the valve 13 is seated on the valve seat 10 d, and the input port 10 a is closed by the valve 13. Therefore, the compressed air inside the brake actuator 3 is kept as it is, and the brake operation state is maintained. Therefore, even if the vehicle is temporarily stopped on a slope or the like and the brake pedal 1a is released, there is no possibility that the vehicle starts moving naturally, and there is no need to apply the side brakes one by one.

Here, the valve body 13 is slidably fitted in a slide hole 16 formed in the piston 14, and is urged in the direction of the valve seat 10d by a spring 17 as shown in FIG. In the state shown, a check valve mechanism that allows only the flow of air from the input port 10a to the output port 10b is configured. The pin 18 serves as a stopper for holding the valve body 13 on the piston 14 and for restricting a moving range of the valve body 13. Further, the piston 1
4 is fitted with a retainer 18a for receiving the spring 15 and preventing the pin 18 from dropping from the piston 14.

For this reason, when the brake pedal 1a is strongly depressed again in the stationary state shown in FIG. 6, the pressure at the input port 10a of the supplied compressed air is applied to the valve against the urging force of the spring 17. Only the body 13 moves to open the input port 10a, and the brake actuator 3 is replenished with compressed air. Therefore, a desired braking force according to the inclination of a slope or the like can be easily obtained.

Next, when the driver prepares for starting of the vehicle by operating an accelerator, a clutch or the like, the controller 7 senses this and de-energizes the electromagnetic switching valve 5. Then, the signal pressure chamber 1
The compressed air in 2 is discharged from the exhaust port 10g in FIG. 5 to the outside (atmosphere) via an external pipe 10h connected to the exhaust port 10g, and the piston 14 Returns to the state. At this time, if the brake pedal 1a is released, the compressed air in the brake actuator 3 is discharged to the outside (atmosphere) 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, skilled operations such as operating the accelerator and clutch while loosening the side brake as in the related art are not required, and a smooth start can be achieved without occurrence of engine stall or vehicle retreat.

[0011]

In the conventional brake pressure control valve 10, when the brake is released by the brake pedal 1a, the compressed air introduced into the signal pressure chamber 12 of the piston 14 is discharged by the exhaust port 10g. , And via an external pipe 10h connected to the exhaust port 10g.

However, if the external pipe 10h connected to the exhaust port 10g is blocked due to freezing in winter or the like, the compressed air introduced into the signal pressure chamber 12 is not released to the atmosphere. The valve element 13 of the control valve 10 is not sufficiently separated from the valve seat 10d. Therefore, there is a problem that the compressed air supplied to the brake actuator 3 is not completely released to the outside, and a brake residual pressure is generated, which may cause a brake drag phenomenon after the brake is released.

The present invention has been made in view of such a point.
The purpose is to solve the above problem, and when the brake is released, even if the external exhaust pipe for exhausting the compressed air introduced into the signal pressure chamber of the piston is blocked, the compressed air is reliably It is an object of the present invention to provide a brake pressure control valve that prevents the occurrence of a brake drag phenomenon after the brake is released to the outside.

[0014]

According to the present invention, there is provided a motor vehicle comprising: (a) an input port connected to a brake valve, an output port connected to a brake actuator, and a passage switching means. A valve housing having a signal pressure port selectively connected to an air tank or an exhaust port and having a valve seat at an open end of the input port; and (b) a valve body at a tip end, Are defined in a signal pressure chamber communicating with the signal pressure port and an output pressure chamber communicating with the output port, and are urged by a first spring in a direction to reduce the signal pressure chamber, and are operated during operation. , While receiving the pressure of the output pressure chamber at the enlarged diameter portion in the biasing direction,
A piston which is actuated by the pressure of the air tank supplied to the signal pressure chamber and seats or separates the valve body from the valve seat to form an on-off valve; and (c) a sliding hole formed in the piston. And a check valve mechanism that allows only the flow from the input port side to the output port side while the valve body is seated on the valve seat by the second spring. Is as follows.

(1) (d) In the housing, there is provided a communication path or an atmosphere chamber communicating with the exhaust port, and the input including the communication path or the atmosphere chamber and a pipe connected to the brake valve. A check valve that allows only a flow from the communication path or the atmosphere chamber to the input port side is provided between the communication port and the air chamber.

(2) In the above (1), the communication passage communicating with the exhaust port is formed in an annular shape on the signal chamber side of the enlarged diameter portion of the piston so that atmospheric pressure acts on the enlarged diameter portion. It is characterized by being performed.

Since the present invention is constructed as described above, the brake pressure control valve is connected to the communication passage communicating with the exhaust port of the control valve or the air pressure (atmospheric pressure) on the atmosphere chamber side during the operation of the brake. Therefore, when the compressed air pressure on the input port side is large, the check valve is closed, but the reverse, that is, when the brake is released, the communication path communicating with the closed exhaust port or the atmosphere chamber side. Is greater than the air pressure (atmospheric pressure) on the input port side, the check valve is opened, and the compressed air pressure in the communication passage or atmosphere chamber communicating with the closed exhaust port is reduced to atmospheric pressure. Be released.

That is, when the check valve is opened, the compressed air pressure on the side of the communication passage communicating with the closed exhaust port or on the atmosphere chamber side is connected to the check valve, the input port and the connection port. The valve is opened to the atmosphere through a pipe, a brake valve when the brake is released, and an exhaust port thereof. Therefore, no residual pressure is generated on the output port side of the brake pressure control valve when the brake is released.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. The brake pressure control valve of the present invention may be configured such that the communication path or the atmosphere is provided between a communication path or an atmosphere chamber communicating with an exhaust port of the control valve and the input port including a pipe connected to the brake valve. A check valve that allows only the flow from the chamber to the input port side is provided, and when the exhaust port side is closed due to freezing or the like when the brake is released, the communication path communicating with the exhaust port or compression of the atmosphere chamber is compressed. The air pressure is released to the atmosphere via the check valve and a pipe connected to the input port.

[Embodiment] FIGS. 1 and 2 show an embodiment of a brake pressure control valve according to the present invention. FIG. 1 is a sectional view showing the structure of the brake pressure control valve, and FIG. In the enlarged main part sectional view showing the state, the same members as those in FIGS. 4, 5, and 6 are denoted by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, the housing 21 of the brake pressure control valve 20 has end housing blocks 21a and 21a.
a and a central housing block 21b, and the end housing block 21a has an input port 10a.
In the central housing block 21b, a signal pressure passage 22 communicating with the signal pressure chambers 12 and 12, a signal pressure port 10f connected via the electromagnetic switching valve 5, and the like are formed. A signal pressure passage 22 communicating with the signal pressure chambers 12 and an exhaust port 10g connected via the electromagnetic switching valve 5 are formed.

In the housing 21, an enlarged diameter portion 14a is provided.
The pistons 14 are slidably disposed, each of which has an output pressure chamber 11 and a signal pressure chamber 1.
2 is defined. Then, the input port 10a and the output port 1
0b is open to the output pressure chamber 11.

The piston 14 having the valve element 13 at its tip is urged in a direction to reduce the signal pressure chamber 12 by a first spring 15 disposed in the output pressure chamber 11.
In operation, while the pressure of the output pressure chamber 11 is received by the enlarged diameter portion 14a in the same urging direction, the valve body is actuated by the compressed air pressure of the air tank 2b supplied to the signal pressure chamber 12. 13 constitutes an on-off valve that is seated on or separated from the valve seat 10d. And the piston 1
Reference numeral 4 denotes a state in which the valve body 13 is seated on the valve seat 10d by a second spring 17 while being interposed in a sliding hole 16 formed in the piston 14, and the input port 10a is closer to the output port 10b. Check valve mechanism that allows only the flow to

In the housing 21, the enlarged diameter portion 1a is located on the signal chamber 12 side of the enlarged diameter portion 14a of the piston 14.
An atmospheric chamber 24 communicating with the annular communication passage 23 is formed so that the atmospheric pressure acts on the annular communication passage 4a.
The communication passage 25 opens to the exhaust port 10g. At the same time, in order to make the annular communication passage 23 communicate with the input port 10a which communicates with the brake valve 1, communication passages 26a, 26 are formed between the end housing blocks 21a, 21a of the housing 21 and the central housing block 21b.
b are formed, and a check valve 27 is disposed between the communication passages 26a and 26b on the end housing block 21a side.

The check valve 27 is connected to the annular communication passage 23.
The valve is opened only when the air pressure on the side is higher than the air pressure on the input port 10a side, that is, disposed so as to allow only the flow of air from the annular communication passage 23 side to the input port 10a side. I have. Instead of the atmosphere chamber 24 communicating with the annular communication passage 23, only the annular communication passage 23 may be enlarged and formed so that the atmospheric pressure acts on the enlarged diameter portion 14a of the piston 14. Good.

The brake pressure control valve 20 is provided with an electromagnetic switching valve 5. Valve chambers 32 and 33 are formed below the plunger 31 in the electromagnetic switching valve 5, and the valve chambers 32 and 33 are connected to each other by a passage 34. Valve bodies 35 and 36 are integrally provided in the valve chambers 32 and 33, and the valve bodies 35 and 36 are connected to the plunger 31 via a rod 37. When the plunger 31 moves up and down, a pair of valve seats 38 and 39 formed at both upper and lower ends of the valve chamber 33 respectively provide the valve bodies 35 and 3.
6 are configured to be separated from each other. Note that these valve bodies 35 and 36 are urged downward in FIG.

In such a brake pressure control valve 20, the valve chamber 33 is connected to the brake pressure control valve 20 via the signal pressure passage 22.
The valve chamber 32 communicates with the signal pressure chamber 12 of the
The air is communicated with the atmosphere through the exhaust port 10g.

As shown in FIG. 3, the input port 10a of the brake pressure control valve 20 is connected to the output port 1c of the brake valve 1 via the pipe 6a, and the output port 10b is connected to the pipe port. 6b, it is connected to the input port of the brake actuator 3. Further, the valve chamber 33 of the electromagnetic switching valve 5 is connected to the air tank 2b via a signal pressure port 10f and a pipe 6d provided in the central housing block 21b.

Next, the operation will be described. The brake pressure control valve 20 thus configured is in a state where the solenoid of the electromagnetic switching valve 5 is demagnetized when the vehicle is running, and the pair of valve bodies 35 and 36 are connected by springs 40 as shown in FIG. It has been pushed down. Therefore, the upper valve body 35 is separated from the valve seat 38 and is in contact with the valve seat 39 of the lower valve body 36. Therefore, no compressed air as signal pressure is introduced into the signal pressure chamber 12 of the brake pressure control valve 20, and the piston 14 is held at the position shown in FIG. The 20 input ports 10a are open.

In this state, when the brake pedal 1a is depressed, the brake valve 1 enters the supply mode, and the compressed air in the air tank 2a is supplied to the input port of the brake pressure control valve 20 via the brake valve 1 and the pipe 6a. It is supplied to the brake actuator 3 through the output pressure chamber 11 through the output port 10b and the pipe 6b, and the brake actuator 3 is operated to cause the wheel cylinder 4 to perform a brake operation. Also, the brake pedal 1a
Is released, the brake valve 1 enters the exhaust mode, and the compressed air in the brake actuator 3 passes through the brake pressure control valve 20 and is discharged to the outside from the exhaust port 1b of the brake valve 1. Therefore, the hydraulic pressure acting on the wheel cylinder 4 disappears, and the brake is released.

If the brake pedal 1a is continuously depressed on a slope or the like while the vehicle is stopped, this state is sensed by the controller 7 (see FIG. 3), and after a predetermined time (for example, 1 Seconds later), the electromagnetic switching valve 5 is excited, and the plunger 31 moves upward as shown in FIG. 2 against the urging force of the spring 40,
The valve body 35 comes into contact with the upper valve seat 38, and the valve body 36 is separated from the lower valve seat 39. For this reason, the signal pressure chamber 12 of the brake pressure control valve 20 is provided through the signal pressure port 10f.
Compressed air is introduced from the air tank 2b.

As a result, the piston 14 is connected to the signal pressure chamber 1
2, the pressure of the spring 15 as shown in FIG.
Is moved against the urging force. The distal end of the piston 14 comes into contact with and is stopped at the step 21c of the end housing block 21a. In this state, the valve body 13 comes into contact with the valve seat 10d to close the input port 10a. I do.

During such a braking operation, the brake pressure control valve 20 applies the input to the input from the air pressure (atmospheric pressure) of the annular communication passage 23 (including the atmosphere chamber 24) communicating with the exhaust port 10g. Since the compressed air pressure on the side of the port 10a is large, the check valve 27 is closed, so that there is no hindrance to the brake operation. Therefore, the brake actuator 3
Is kept 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 moving naturally, and there is no trouble of applying the side brakes one by one.

Next, when the driver prepares for starting of the vehicle by operating the accelerator, the clutch and the like, the controller 7 senses this and makes the electromagnetic switching valve 5 demagnetized. When the electromagnetic switching valve 5 is in a demagnetized state, the valve bodies 35 and 36 are moved downward by the urging force of the spring 40, and the valve body 35 separates from the valve seat 38 as shown in FIG. The valve element 36 contacts the valve seat 39. Therefore, the brake pressure control valve 2
The compressed air in the signal pressure chamber 12 of the zero pressure is supplied to the signal pressure passage 22, the valve chamber 33, the passage 34, the valve chamber 32, the passage 41 and the exhaust port 10.
g to the outside.

In this case, if the external pipe 10h connected to the exhaust port 10g is closed due to freezing or the like, the compressed air introduced into the signal pressure chamber 12 is not released to the atmosphere. The compressed air pressure in the annular communication passage 23 (including the atmosphere chamber 24) becomes larger than the air pressure (atmospheric pressure) on the input port 10a side, the check valve 27 is opened, and the closed exhaust port 10g is opened. The compressed air pressure in the annular communication passage 23 communicating with the valve is released to the atmosphere through the check valve 27, the input port 10a, the pipe 6a, the brake valve 1, and the exhaust port 1b.

Accordingly, the piston 14 returns to the original position by the urging force of the spring 15. Then, the compressed air in the brake actuator 3 is discharged to the outside from the exhaust port 1b of the brake valve 1, and the brake is released to be able to start. Therefore, particularly when starting on an uphill road, a skilled operation such as operating the accelerator or clutch while loosening the side brake as in the related art is not required, and a smooth start can be achieved without occurrence of engine stall or vehicle retreat.

The technique of the present invention is not limited to the technique in the above-described embodiment, but may be implemented by means of other modes which perform the same function. Can be changed or added.

[0038]

As is apparent from the above description, according to the brake pressure control valve of the present invention, a communication passage or an atmosphere chamber communicating with the exhaust port is provided in the housing. Since a check valve that allows only the flow from the communication path or the atmosphere chamber to the input port side is disposed between the input port including the pipeline connected to the brake valve,
When the brake is released, even if an external exhaust pipe for discharging the compressed air introduced into the signal pressure chamber of the piston is closed, the compressed air is reliably exhausted, and the brake is dragged after the brake is released. The occurrence of the phenomenon can be prevented beforehand.

Further, the exhaust system according to the present invention is a brake system exhaust means.
It is highly reliable and can prevent entry of foreign substances such as water and dust. This brake system exhaust means has the advantages of simply adding and arranging a check valve, having a simple structure, being inexpensive, and having high reliability. Further, the conventional brake pressure control valve can be easily replaced with that of the present invention without major modification, including during use.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a brake pressure control valve of the present invention, and is a cross-sectional view showing a structure of the brake pressure control valve.

FIG. 2 is an enlarged sectional view of an essential part showing an operation state of a brake pressure control valve of FIG. 1;

FIG. 3 is a system diagram of a brake operating device in which a conventional brake pressure control valve is used.

FIG. 4 is a sectional view showing a structure of a conventional brake pressure control valve.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

6 is an enlarged cross-sectional view of a main part of an operation state of the brake pressure control valve shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake valve 2a, 2b Air tank 3 Brake actuator 5 Electromagnetic switching valve 6a Pipe line 10a Input port 10b Output port 10d Valve seat 10f Signal pressure port 10g Exhaust port 11 Output pressure chamber 12 Signal pressure chamber 13 Valve body 14 Piston 14a Enlarged part 15, 17 Spring 16 Sliding hole 20 Brake pressure control valve 21 Housing 23 Annular communication passage 24 Atmosphere chamber 26a, 26b Communication passage 27 Check valve

Claims (2)

[Claims] (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 an exhaust port via a passage switching means. A valve housing having a valve seat at an open end of the input port; and (b) a signal pressure chamber having a valve body at a tip end and communicating with the signal pressure port in the valve housing and the output port. The signal pressure chamber is biased by the first spring in a direction to reduce the signal pressure chamber, and when activated, the pressure of the output pressure chamber is increased in the biasing direction by the enlarged diameter portion. Receiving the pressure, actuated by the pressure of the air tank supplied to the signal pressure chamber, and seating or separating the valve body from the valve seat to form an on-off valve; and (c) the piston Through the formed sliding hole And, second
A check valve mechanism that allows only the flow from the input port side to the output port side in a state where the valve body is seated on the valve seat by the spring of (b), A communication path or an atmosphere chamber communicating with the exhaust port is provided in the housing, and the communication path or the atmosphere chamber is provided with:
A check valve that allows only a flow from the communication path or the atmosphere chamber to the input port side is provided between the input port including a pipe connected to the brake valve. Brake pressure control valve. 2. The communication passage communicating with the exhaust port is formed in an annular shape on the signal chamber side of the enlarged diameter portion of the piston so that atmospheric pressure acts on the enlarged diameter portion. The brake pressure control valve according to claim 1.