JPH10250566A - Brake pressure control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the generation of a strange sound from a valve body even though extra-stepping a brake pedal slowly particularly in its extra- stepping method, when a vehicle is in a stopping condition, and to omit a spring to energize the valve body to a valve seat side, as to a brake pressure control valve. SOLUTION: In this brake pressure control valve 20 of a brake operation device, a spring to energize the valve body 23 of the control valve 20 to the valve seat 10d side is omitted, and at the same time, a through hole 24d is provided between the end face of a sliding hole 24a formed on a piston 24, and a signal pressure chamber 12, and a small diameter fitting part 23a is formed at the signal pressure chamber 12 side of the valve body 23, this small diameter fitting part 23a is fitted slidable to the through hole 24b through a seal member 25 in the airtight condition, and the valve body 23 is energized to the valve seat 10d side through the small diameter fitting part 23a, by the air pressure fed to the signal pressure chamber 12, in the operation time.

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 detected by the controller 7, and after a lapse of a predetermined time (for example, one second), the electromagnetic switching valve 5 is turned on. Is excited, and 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 piston 14 having the valve element 13 in the brake pressure control valve 10 is urged by the compressed air.

As a result, the piston 14 is moved by the pressure of the signal pressure chamber 12 against the urging force of the first spring 15 as shown in the enlarged view of FIG. Then, the piston 14 stops when the enlarged diameter portion 14a comes into contact with 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, the vehicle does not start moving naturally, and there is no need to apply the side brake one by one.

Here, the valve body 13 is slidably fitted in a slide hole 16 formed in the piston 14, and is urged by a second spring 17 in the direction of the valve seat 10d. In the state shown in FIG.
A check valve that allows only the flow of air from the a side to the output port 10b side 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.

For this reason, when the brake pedal 1a is depressed again strongly in the stationary state shown in FIG. 5, only the valve element 13 moves due to the pressure of the supplied compressed air at the input port 10a, and the input port 10a is moved. The brake actuator 3 is released and the compressed air is replenished to the brake actuator 3. 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
2 is discharged to the outside from an exhaust port (not shown), and the piston 14
It returns to the original state by the urging force of. At this time, if the brake pedal 1a is released, 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, 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]

When the brake pedal 1a is further depressed in the state where the pressure of the conventional brake pressure control valve 10 is maintained, that is, when the vehicle is stopped on a hill or the like, the input port 10a of the control valve 10 becomes open. The supplied compressed air opens the valve body 13 against the urging force of the second spring 17 and is introduced into the brake actuator 3.

However, at this time, the control valve 10
When the pressure rising speed of the compressed air supplied to the input port 10a of the valve body 13 is low, that is, when the brake pedal 1a is slowly increased and depressed, the valve body 13 opens and closes the input and output ports 10a, 10a.
The opening and closing are repeated so as to balance the pressure of the compressed air in 10b. For this reason, there has been a problem that the valve body 13 abnormally vibrates and generates abnormal noise. This has given the driver discomfort.

On the other hand, since the second spring 17 has an extremely weak urging force as compared with the first spring 15, there is a possibility that a characteristic change due to torsion may occur when the control valve 10 is assembled. There was a problem.

[0014] The present invention has been made in view of such a point.
An object of the present invention is to provide a brake pressure control valve which solves the above-mentioned problems and which does not generate abnormal noise from its valve body even when the brake pedal is stepped on, especially when the vehicle is stopped. It is in.

Another object of the present invention is to provide a brake pressure control valve having a structure in which a spring (the second spring) for urging the valve body is omitted.

[0016]

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 interposed in the second spring and allowing 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 second spring. ,It is as follows.

(1) (d) The second spring is eliminated, a through hole is provided between the end face of the sliding hole formed in the piston and the signal pressure chamber, and the valve body is provided with a through hole. A small-diameter fitting portion is formed on the signal pressure chamber side, and the small-diameter fitting portion is fitted in the through-hole in an airtight and slidable manner via a seal member. The valve body is urged toward the valve seat via the small-diameter fitting portion by the introduced air pressure.

Since the present invention is configured as described above, the second spring for urging the valve body is eliminated, and the valve body is formed in the through hole provided in the piston. The small-diameter fitting portion is slidably fitted via a sealing member, for example, an O-ring, and the abnormal vibration generated in the valve body is attenuated by the sliding resistance generated at the fitting portion and the elasticity of the sealing member. , Let it be absorbed. In operation, instead of the biasing force of the second spring, the pressure from the air tank introduced into the signal pressure chamber is biased toward the small-diameter fitting portion end face of the valve body during operation.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail. The brake pressure control valve of the present invention eliminates the conventional second spring that urges the valve element, forms an end face of a sliding hole formed in the piston, and slides the valve element, and the signal pressure chamber. A through hole is provided in the direction of the valve element shaft (or the piston axis) therebetween, and a small diameter fitting portion formed on the signal pressure chamber side of the valve element is provided in the through hole with a sealing member, for example, an O-ring. Are slidably fitted through the airtight. Then, instead of the biasing force of the deleted second spring, at the time of operation, the end face of the small diameter fitting portion is pressed by the pressure from the air tank introduced into the signal pressure chamber, and the valve body is moved. It is biased to the valve seat side.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 and 2 are views showing an embodiment of a brake pressure control valve according to the present invention. FIG. 1 is a cross-sectional view showing the structure of the brake pressure control valve, and FIG. In the cross-sectional view, the same members as those in FIGS. 3, 4, and 5 are denoted by the same reference numerals, and 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.
The signal pressure passages 22 are formed in the central housing block 21b to communicate with the signal pressure chambers 12, 12, respectively. Pistons 24 are arranged in the housing 21, and each of the pistons 24 defines an output pressure chamber 11 and a signal pressure chamber 12. The input port 10a and the output port 10b open to the output pressure chamber 11.

The piston 24 is urged in a direction to reduce the signal pressure chamber 12 by a first spring 15 disposed in the output pressure chamber 11. The piston 24 has a sliding hole 24a formed at the front end (on the side of the input port 10a), and the shaft of the piston 24 (or between the signal pressure chamber 12 and the end face of the sliding hole 24a). A through hole 24b is formed in the direction of the valve element 23), and the sliding hole 24a
The valve body 23 is slidably fitted into the valve body 23. A small-diameter fitting portion 23a formed on the signal pressure chamber 12 side of the valve body 23 is fitted in the through hole 24b with a sealing member such as an O-ring 25. It is slidably fitted in an airtight manner through the intermediary. For this reason, at the time of operation, the pressure from the air tank 2b introduced into the signal pressure chamber 12 pressurizes the end face of the small-diameter fitting portion 23a to urge the valve body 23 toward the valve seat 10d. .

The valve 23 is engaged with and held by the piston 24 by a pin 26 inserted through the valve 23. An annular retainer 26 a is fitted to the piston 24 so that the pin 26 does not fall out of the through hole of the piston 24.

The brake pressure control valve 20 is provided with an electromagnetic switching valve 30. A plunger chamber 32 and a valve chamber 33 are formed below the plunger 31 in the electromagnetic switching valve 30, and the plunger chamber 32 and the valve chamber 33 are connected to the passage 3.
4 communicate with each other. A valve body 35 having valve portions 35a and 35b is provided in the valve chamber 33. The valve body 35 is connected to the plunger 31 via a rod 36.
It is connected to.

When the plunger 31 moves up and down,
In the valve chamber 33, the valve portions 35a and 35b are configured to be separated from and connected to valve seats 37 and 38 formed at a connection end with the pipe 6d and an end of the passage 34, respectively. The valve body 35 is biased downward in FIG. 1 by a spring 39 in a non-excited state. The spring 40 provided in the valve chamber 33 urges the valve body 35 upward with a weaker urging force than the spring 39.

In such a brake pressure control valve 20, the valve chamber 33 communicates with the signal pressure chamber 12 of the brake pressure control valve 20 via the signal pressure passage 22. Plunger room 3
2 is connected to the atmosphere via a passage 41.

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. The valve chamber 33 of the electromagnetic switching valve 30 is connected to the air tank 2b via a pipe 6d connected to the central housing block 21b.

Next, the operation will be described. In the brake pressure control valve 20 configured as described above, the solenoid of the electromagnetic switching valve 30 is in a non-excited state when the vehicle is running,
The valve body 35 is pushed down by a spring 39 as shown in FIG. Therefore, the upper valve portion 35b
Is separated from the valve seat 38, and the lower valve portion 35a is
Is in contact with Therefore, the compressed air as the signal pressure is not introduced into the signal pressure chamber 12 of the brake pressure control valve 20, and the piston 24 is held at the position shown in FIG. The input port 10a of the pressure control valve 20 is open.

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

If the brake pedal 1a is continuously depressed while the vehicle is stopped on a slope or the like, this state is sensed by the controller 7 (see FIG. 3), and after a predetermined time (for example, 1 2 seconds later, the electromagnetic switching valve 30 is excited, the plunger 31 moves upward as shown in FIG. 2 against the urging force of the spring 39, and the valve portion 35b of the valve body 35 is moved to the upper valve seat 38. Abuts,
The valve portion 35a is separated from the lower valve seat 37. Therefore, the compressed air from the air tank 2b is introduced into the signal pressure chamber 12 of the brake pressure control valve 20 via the pipe 6d.

As a result, the piston 24 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 enlarged diameter portion 24c of the piston 24 comes into contact with the step portion 21c of the valve housing 21a and is stopped there, but is slidable into the through hole 24b by the compressed air introduced into the signal pressure chamber 12. Small-diameter fitting portion 23a of the valve body 23 fitted to
Is pressed, and the valve body 23 is urged toward the valve seat 10d. In this state, the valve element 23 contacts the valve seat 10d and closes the input port 10a.

In this case, a small-diameter fitting portion 23a formed in the valve body 23 is slidably fitted to the through hole 24b formed in the piston 24 via an O-ring 25. The abnormal vibration generated in the valve body 23 is attenuated by the sliding resistance of the fitting portion and the elasticity of the O-ring 25.
Absorbed noise can be prevented from being generated.

Therefore, the compressed air inside 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,
There is no risk of the vehicle starting to move naturally, and there is no hassle of applying the side brakes.

When the brake pedal 1a is strongly depressed again in the stationary state shown in FIG. 2, the valve body 23 moves from the signal pressure chamber 12 to the end face of the small diameter fitting portion 23a by the pressure in the input port 10a. The valve body 23 moves away from the valve seat 10d against the pressing pressure, and the compressed air is supplied to the brake actuator 3. Therefore, a desired brake holding force according to the degree of inclination of a slope or the like can be easily obtained.

When the pressure in the output pressure chamber 11 is equal to or higher than a predetermined pressure, the piston 24 moves against the pressure in the signal pressure chamber 12, and the valve body 23 separates from the valve seat 10d. Therefore, when the brake pedal 1a is released, the output pressure chamber 11
Is discharged from the exhaust port 1b of the brake valve 1,
When the pressure in the output pressure chamber 11 reaches a predetermined pressure, the piston 24
Is moved, and the input port 10a is closed. Therefore, the pressure in the output pressure chamber 11 is balanced with the pressure in the signal pressure chamber 12, so that even if the brake is operated for a long time, no excessive pressure acts on the pipe 6b or the like.

Next, when the accelerator or clutch is operated to prepare for starting the vehicle, the controller 7 senses this and turns off the electromagnetic switching valve 30. The electromagnetic switching valve 3
0 is in a non-excited state, the valve body 35
Is moved downward by the urging force of
The valve portion 35b separates from the valve seat 38, and the valve portion 35a contacts the valve seat 37. Therefore, the brake pressure control valve 20
The compressed air introduced into the signal pressure chamber 12 is discharged outside through the signal pressure passage 22, the valve chamber 33, the passage 34, the plunger chamber 32, and the passage 41. Accordingly, the piston 24 returns to the original position by the urging force of the first 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 via the brake pressure control valve 20, and the brake is released to be able to 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 prior art are not required, and a smooth start can be made without occurrence of engine stall or vehicle retreat. It is.

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

[0039]

As is apparent from the above description, according to the brake pressure control valve of the present invention, the second spring for biasing the conventional valve element is eliminated, and the sliding formed on the piston is eliminated. A through hole is provided between the end face of the hole and the signal pressure chamber,
And forming a small diameter fitting portion on the signal pressure chamber side of the valve body,
The small-diameter fitting portion is slidably fitted to the through hole in an airtight manner via a seal member, and when activated, the air pressure introduced into the signal pressure chamber causes the small-diameter fitting portion to pass through the small-diameter fitting portion. Since the valve body is urged toward the valve seat side, generation of abnormal noise from the valve body is prevented even when the vehicle is stopped, even if the brake pedal is increased slowly, particularly when the brake pedal is increased. be able to.

At the same time, the brake pressure control valve can have a structure in which a spring (the second spring) for urging the valve element is omitted. Therefore, when assembling the brake pressure control valve, there is no possibility that a characteristic change due to the torsion of the spring occurs, and the assembling property can be improved.

[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 the 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 an enlarged cross-sectional view of an essential part of an operation state of the brake pressure control valve shown in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 brake valve 2a, 2b air tank 3 brake actuator 10a input port 10b output port 10d valve seat 11 output pressure chamber 12 signal pressure chamber 15 first spring 17 second spring 20 brake control valve 21 housing 23 valve body 23a small diameter fitting Part 24 piston 24a sliding hole 24b through hole 25 O-ring 26 sliding hole 30 solenoid switching valve

Claims (1)

[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 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 (d), 2, a through hole is provided between the end surface of the sliding hole formed in the piston and the signal pressure chamber, and a small-diameter fitting portion is provided on the signal pressure chamber side of the valve body. Forming the small diameter fitting portion in the through hole,
The valve body is slidably fitted in an airtight manner via a seal member, and when activated, the valve body is urged toward the valve seat via the small-diameter fitting portion by air pressure introduced into the signal pressure chamber. A brake pressure control valve, characterized in that the brake pressure is controlled.