JPH08301088A - Brake pressure control valve device for air brake system - Google Patents

Abstract

PURPOSE: To provide a technology which can prevent both generation of residual pressure on the brake actuator B/C side caused by blocking-up of an exhaust port and a rising delay of brake actuation. CONSTITUTION: A connecting passage 21b to connect a first control valve 52 and an exhaust port 14 to each other is communicated with the inlet 12 side by an auxiliary passage 66. A check valve 60 which opens according to an increase in internal pressure on the connecting passage 21b side though the valve is always closed, is arranged in this auxiliary passage 66. The check valve 60 allows a movement of air proceeding to an inlet 12 from the connecting passage 21b side of the exhaust port 14 when the exhaust port 14 is blocked up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air brake system provided in a vehicle such as a truck or a bus, which is equipped for brake control such as anti-skid control or traction control, and is based on a wheel rotation state. The present invention relates to a brake pressure control valve device for reducing, maintaining, or increasing the pressure supplied to a brake.

[0002]

BACKGROUND OF THE INVENTION In general, a brake pressure control valve system is located between a brake valve and a brake actuator. As one of such brake pressure control valve devices, it is provided between an inlet connected to a brake valve and an outlet connected to a brake actuator, and is urged to a closed position by receiving pilot pressure, When the pilot pressure disappears, it is installed between the holding valve that opens by receiving the pressure on the inlet side or the outlet side and the exhaust port that communicates with the atmosphere. It is energized, and the exhaust valve that opens by receiving the pressure on the outlet side with the disappearance of the pilot pressure and the position where the pilot pressure chamber of the holding valve communicates with the exhaust port based on the brake holding signal from the outside, Based on the first control valve that switches to a position that supplies pilot pressure to the pilot pressure chamber and the brake slack signal from the outside, the pilot of the exhaust valve From a position for supplying the pilot pressure to the chamber are provided with a second control valve switched to the position for communicating the pilot pressure chamber to the exhaust port. Normally, the pilot pressure supplied to each pilot pressure chamber is the brake pressure introduced from the brake valve through the inlet. Then, brake control such as anti-skid control or traction control is performed by the action of the holding valve and the exhaust valve according to the switching of the first and second control valves.

By the way, in a state in which the brake operation is normally released, the pilot pressure chamber of the holding valve is in communication with the exhaust port through the first control valve. Further, the pilot pressure chamber of the exhaust valve is in a state where the pilot pressure is supplied in response to the brake pressure being sent from the brake valve through the second control valve. Under these conditions, during normal brake operation, the brake pressure (air) introduced inside from the brake valve through the inlet.
Is supplied to the brake actuator through the outlet while supplying pilot pressure to the pilot pressure chamber of the exhaust valve to urge the exhaust valve to the closed position and open the holding valve by the pressure. When the brake is released, the air supplied to the brake actuator flows backward from the outlet side to the inlet side through the holding valve that is open, and is discharged from the brake valve side to the atmosphere. On the other hand, as the brake is released, the pilot pressure in the pilot pressure chamber of the exhaust valve disappears, so part of the air that flows backward from the outlet side is discharged to the atmosphere from the exhaust port by opening the exhaust valve. Will be.

[0004]

Since such a brake pressure control valve device is attached to an externally exposed portion such as a vehicle body frame near an axle, the brake pressure control valve device is mounted on a vehicle in a snowy region or a cold region. When used, snow or ice may adhere to the exhaust port of the brake pressure control valve device, freeze, and block the exhaust port. The blockage of the exhaust port occurs, for example, from a state where snow completely blocks the opening of the exhaust port. In many cases, the exhaust port is provided with a check valve for preventing foreign matter from entering from the outside, and a rubber plate-shaped valve body is used as the check valve. As the valve freezes and the valve function is lost, the exhaust port is blocked. When the exhaust port is clogged in this way, the air that should be discharged to the atmosphere through the exhaust port is not exhausted.

When the brake pressure control valve device is in the non-operating state, the first control valve is positioned so that the pilot pressure chamber of the holding valve communicates with the exhaust port. Therefore, when the exhaust port is clogged in such a state, especially when releasing the brake in which air flows to the exhaust port side, the air to be exhausted to the outside from the exhaust port is not exhausted and No. 1 flows into the pilot pressure chamber of the holding valve through the communication passage between the control valve and the control valve. Then, such air is trapped in the space from the exhaust port to the pilot pressure chamber of the holding valve.
The air thus confined in the pilot pressure chamber of the holding valve acts so as to increase the urging force of closing the holding valve. Therefore, even if the pressure on the inlet side is released, the pressure on the outlet side is not released by the amount corresponding to the increased biasing force, and a residual pressure is generated in the brake actuator. The pressure of the air trapped in the space from the exhaust port to the pilot pressure chamber of the holding valve is increased by the subsequent repetition of further brake operation-release, and the residual pressure on the brake actuator side is also increased accordingly. Such residual pressure on the brake actuator side causes a problem of friction of the brake.

[0006]

[Related Art] In the above-mentioned brake pressure control valve device,
In order to prevent the residual pressure that causes the friction of the brake from occurring on the side of the brake actuator, for example, Japanese Patent Laid-Open No. Hei 2
As disclosed in JP-A-256555, a check valve that allows only the flow of air from the outlet side to the inlet side is provided in a passage formed in parallel with the holding valve, or JP-A-3-292242. As shown in Fig. 3, a check valve that bypasses the holding valve and the exhaust valve and directly connects the inlet side and the outlet side is provided, and only the air flow from the outlet side to the inlet side is allowed in the pipeline. It is known to provide a valve. However, even in those taking measures to prevent the residual pressure of the brake actuator as shown in these publications, a part of the air supplied to the brake actuator is usually accompanied by the release of the brake, There is no change in flow to the exhaust port side through the outlet and exhaust valve. Therefore, when the exhaust port is blocked as described above, the air to be exhausted to the outside is confined in the space from the exhaust port to the pilot pressure chamber of the holding valve, and the holding valve is closed by the air pressure. The problem of being biased to the position cannot be resolved.

Even in the structure described in the above publication, the pressure of the air supplied from the brake valve through the inlet at the start of normal brake operation is such that the pilot pressure chamber of the holding valve from the exhaust port due to the blockage of the exhaust port. The holding valve cannot be opened until the pressure rises beyond the containment pressure in the space leading to. Therefore, the pressure supply to the brake actuator side through the holding valve and the outlet is delayed by that amount, which causes a problem that the actual start of the brake operation is delayed with respect to the brake operation.

[0008]

SUMMARY OF THE INVENTION In consideration of the above points, an object of the present invention is to provide a technique capable of preventing both the residual pressure generation on the brake actuator side and the delay in the startup of the brake operation due to the blockage of the exhaust port. And

[0009]

As means for solving such a problem, according to the present invention, an auxiliary passage for connecting a communication passage between the first control valve and the exhaust port to the inlet side is provided, and the auxiliary passage is always provided with the auxiliary passage. A brake pressure control valve device is configured by closing the valve, but opening the valve in response to an increase in internal pressure on the side of the communication passage, and providing a check valve that allows air movement from the communication passage side of the exhaust port toward the inlet. .

[0010]

According to the brake pressure control valve device in which the check valve is provided at such a specific position, the air confined in the space from the exhaust port to the pilot pressure chamber of the holding valve due to the blockage of the exhaust port is reversed. It can be escaped through a stop valve.
The above-mentioned communication passage between the first control valve and the exhaust port constitutes a part of the space in which the air, which is a problem here, is enclosed. Therefore, the auxiliary passage that connects the communication passage to the entrance side is also a passage that connects the space in question to the entrance side. The above-mentioned check valve provided in such an auxiliary passage opens due to the pressure difference between the pressure of the air trapped in the space and the pressure of the inlet side as the inlet side becomes pressureless when the brake is normally released. To be done. When the check valve is opened, the air contained in the space escapes to the inlet side. The air that escapes to the inlet side at this time is exhausted to the outside, for example, from another exhaust port provided in the brake valve connected to the inlet.

Moreover, the check valve does not open and close each time the brake is actuated, and is also advantageous in terms of durability. In other words, this check valve is kept closed because the internal pressure does not rise on the communication passage side when the exhaust port is not normally closed, and air is contained by closing the exhaust port. The opening / closing operation is performed only when the internal pressure rises. Therefore, such a check valve is not required to have relatively high durability, and can be made small and inexpensive.

[0012]

1 is a sectional view showing a schematic structure of a brake pressure control valve device 10 according to an embodiment of the present invention. The housing of the brake pressure control valve device 10 has an inlet 12 connected to the brake valve B / V and an outlet 13 connected to a brake actuator (for example, a brake chamber or an air hydraulic brake booster) B / C. Further, it has an exhaust port 14 communicating with the atmosphere.
Normally, the exhaust port 14 opens downward, and there is a check valve 44 for preventing foreign matter from entering from there.
Is provided.

A holding valve 20 and an exhaust valve 30 for brake control are provided inside the housing of the brake pressure control valve device 10. Both the holding valve 20 and the exhaust valve 30 are diaphragm type valves.
The holding valve 20 is located in the middle of the passage that connects the inlet 12 and the outlet 13, and receives the pressure on the inlet 12 side or the outlet 13 side against the force of a spring that pushes the diaphragm in the valve closing direction. Is opened by. The holding valve 20 has a pilot pressure chamber 25 that receives a pilot pressure behind it, and is biased to a valve closed position by receiving a pilot pressure from the outside. On the other hand, the exhaust valve 30 has the outlet 1
3 is in the middle of the passage connecting the exhaust port 14 and the diaphragm 13 and is opened by receiving the pressure on the outlet 13 side against the force of a very light spring which pushes the diaphragm in the valve closing direction. The exhaust valve 30 has a pilot pressure chamber 35 behind which a pilot pressure is received, and is biased to a valve closed position by receiving a pilot pressure from the outside. Each pilot pressure here is a brake pressure introduced from the brake valve B / V through the inlet 12.

A first control valve 52 and a second control valve 53 are provided so as to correspond to the holding valve 20 and the exhaust valve 30, respectively. These first and second control valves 5
Reference numerals 2 and 53 are electromagnetic valves having 3 ports and 2 positions. The first control valve 52 is arranged at an intermediate position of the first signal pressure line 21 that extends to connect the inlet 12 and the exhaust port 14. The first control valve 52 communicates with the pilot pressure chamber 25 of the holding valve 20 through the first signal pressure port 21a and communicates with the exhaust port 14 through the communication passage 21b. When not operating, the pilot pressure chamber 25 is cut off from the inlet side and positioned so as to communicate with the exhaust port 14. Based on the brake holding signal from the external control unit section, the pilot pressure chamber 2
5 is cut off from the exhaust port 14 and switched to a position where it communicates with the inlet 12. Similarly, the other second control valve 53 is also arranged at an intermediate position of the second signal pressure line 31 that extends to connect the inlet 12 and the exhaust port 14. Second control valve 53
Is connected to the pilot pressure chamber 35 of the exhaust valve 30 through the second signal pressure port 31a, and is connected to the exhaust port 14 through the passage 31b. When not operating, the pilot pressure chamber 35 is cut off from the exhaust port 14 and communicated with the inlet 12, and the pilot pressure chamber 35 is shut off from the inlet 12 based on the brake slack signal from the external control unit. Then, it is switched to a position where it communicates with the exhaust port 14.

[0015]

[Table 1]

In Table 1 above, the holding valve 20, the exhaust valve 30, and the control valves 52 and 53 corresponding to the holding valve 20 and the exhaust valve 30, respectively.
The individual switching modes of FIG. When the brake is actuated, (injection) indicates a state in which air is delivered from the brake valve B / V, and (slack) indicates a state in which air in the brake actuator B / C is exhausted. And (holding) shows the state where the air in the brake actuator B / C is kept at a constant pressure. Further, in the first control valve and the second control valve, (OFF) indicates a state in which those solenoid coils are not energized, that is, a so-called non-excitation state, and (ON) indicates
It shows that it is in the excited state. In the holding valve and the exhaust valve, the presence / absence of pilot pressure in each pilot pressure chamber is determined by (present) or (none), and the open / closed state of the valve is designated by (OPEN) or (CLOSE).
Represented respectively.

When the brake pressure control valve device 10 is not operated,
Both control valves 52 and 53 are in a non-excited state, one first control valve 52 connects between the exhaust port 14 and the pilot pressure chamber 25 of the holding valve 20, and the other second control valve 53 is an inlet. 12-The pilot pressure chamber 35 of the exhaust valve 30 is connected (FIG. 1 shows such a state). In such a state, normal brake operation-release is performed.

When the control unit determines that the wheels tend to lock (when the brake pressure control valve device 10 requires brake control), first,
The control unit section issues a brake holding signal to the holding valve 20. Based on this signal, the first control valve 52 is excited and the position of the control valve is switched. By this switching, the first control valve 52 connects between the inlet 12 and the pilot pressure chamber 25. In response to this, the holding valve 20 receives the pilot pressure in its pilot pressure chamber 25 and is urged to the valve closed state to shut off the inlet 12 side and the outlet 13 side.
In this way, the braking force by the brake actuator B / C is kept constant. Subsequently, the control unit section issues a brake loosening signal to the exhaust valve 30. Based on this signal, the second control valve 53 is excited and the position of the control valve is switched. By this switching, the second control valve 53 connects the exhaust port 14 and the pilot pressure chamber 35. In response to this, the exhaust valve 30 loses the pilot pressure to the pilot pressure chamber 35, and the outlet 13 side and the exhaust port 1
The valve is opened due to the pressure difference from the 4 side. In this way, the braking force by the brake actuator B / C is relaxed. After that, the control valves 52 and 53 are switched via the control unit section based on the state of the wheels.
Proper braking control is performed by repeating braking pressure-holding-releasing.

Now, such a brake pressure control valve device 1
At 0, the check valve 60 located above the exhaust port 14 in FIG. 1 is one of the points of the present invention. The check valve 60 is provided in a passage 31b that connects the second control valve 53 and the exhaust port 14, and a through hole 64 that connects the second signal pressure port 31a. The through hole 64 constitutes a part of the auxiliary passage 66 that connects the communication passage 21b to the inlet 12 side. That is, the passage 31b includes the communication passage 21b (a part of the first signal pressure conduit 21) that connects the first control valve 52 and the exhaust port 14 from the exhaust port 14 to the pilot pressure chamber 25 of the holding valve 20. It is the part that communicates with the space. The second signal pressure port 31a is a portion that communicates with the inlet 12 side through the second control valve 53 when not operating. Therefore, the through hole 64 that connects the passage 31b and the second signal pressure port 31a is a space (or the first control valve 5) that extends from the exhaust port 14 to the pilot pressure chamber 25 of the holding valve 20.
Inlet 1 through connecting passage 21b) connecting 2 and exhaust port 14
It is communicated with the second side and constitutes a part of the auxiliary passage 66.
That is, the auxiliary passage 66 also serves as a communication passage between the pilot pressure chamber 35 of the exhaust valve 30 and the inlet 12 via the second control valve 53.

The check valve 60 is provided in the through hole 64 forming a part of the auxiliary passage 66, and allows the air movement from the communication passage 21b side of the exhaust port 14 toward the inlet 12 side,
The opposite flow is prohibited. Auxiliary passage 66 and check valve 6
Providing 0 at such a position is preferable from the viewpoint that the existing communication passage can be used, from the viewpoint of simplifying and compacting the internal structure of the brake pressure control valve device 10.
However, for example, instead of this auxiliary passage 66, the second
A passage may be provided that bypasses the control valve 53 and directly connects the exhaust port 14 and the inlet 12, and the check valve 60 may be arranged in such a passage.

2 and 3 are diagrams showing a more specific configuration of the brake pressure control device 10 whose circuit configuration is shown in FIG. In particular, FIG. 3 is a sectional view taken along line 3-3 of FIG. In FIG. 2, there is an inlet 12 and an outlet 13 so as to extend laterally above the housing. Below the housing, there is an exhaust port 14 that opens downward.

The exhaust port 14 is formed at the lower end of a cylindrical portion 41 of the housing extending in the vertical direction, and a check valve 44 is mounted therein. The check valve 44 is composed of a round plate 44c attached to the lower end of a shaft portion 44a extending coaxially with the tubular portion 41, and a rubber disc 44d provided so as to cover the opening of the tubular portion 41. . Round plate 44
An umbrella-shaped baffle 44b surrounding the shaft portion 44a is provided above the c, and the baffle 44b and the round plate 44c are provided with a plurality of holes arranged in the circumferential direction. Normally, the rubber disc 44d is supported by the round plate 44c, and covers the opening of the tubular portion 41 and the hole of the round plate 44c to prevent foreign matter from entering the inside. Then, when the air inside is exhausted, the rubber disc 44d is warped outward by the force of the air, and accordingly, the air is exhausted through the respective holes of the baffle 44b and the round plate 44c.

Further, in FIG. 3, a holding valve 20 and an exhaust valve 30 are provided so as to be distributed to both sides of the housing. On the rear side of the holding valve 20 and the exhaust valve 30 in FIG. 3, the corresponding first control valve 52 and second control valve 53 are located.

The through hole 64 forming a part of the auxiliary passage 66 and the check valve 60 provided in the through hole 64 are provided in the exhaust port 14
It is arranged below the exhaust valve 30 so as to line up with. The check valve 60 includes a recess 61 that is open to the outside of the housing.
A ball valve body 60a provided in the interior of the recess 61 facing the valve seat 62 located at the bottom, a valve spring 60b for urging the ball valve body 60a in its seating direction, and a spring bearing for the valve spring 60b, which is a recess. 61 and a plug member 60c mounted from the outside. The plug member 60c includes a seal member 67 that shields the inside of the recess 61 from the outside, and a metal fitting member 68 that prevents the plug member 60c itself from coming off from the recess 61. Such a check valve 60
The recess 61 is configured to be detachably mounted from the outside, and workability such as mounting the check valve 60 is improved. Further, the recess 61 is provided in an empty space of a conventional device, and the mounting space thereof is also effectively used. In addition, in FIG. 3, a ball valve body 60a
The opening 65 visible to the rear of is the opening portion of the second signal pressure port 31a extending to the second control valve 53.

In the embodiment shown in the figure, the first and second control valves 52 and 53 for controlling the pilot pressures of the holding valve 20 and the exhaust valve 30 are electromagnetic type, that is, the control unit section. , Which can be switched by an electric command signal is used, but other types can be used. For example, like an air pilot valve,
An example is one that receives a command signal by pressure and switches. When the first and second control valves are electromagnetic type, a mechanism for converting an electric command signal output from the control unit section into a pressure signal is not required, so that the configuration of wiring, piping, etc. is simplified. It is also advantageous in terms of responsiveness.

Further, in the embodiment described above, the ball valve body 6
Although the check valve 60 including 0a is used and both the valve body and the valve seat are made of metal, at least a portion of the valve body that is attached to and detached from the valve seat may be formed of a rubber member. FIG. 4 shows an example of such another check valve 160, in which a single ball valve body 60a is replaced by two members, that is, a valve seat 16
2 is an annular rubber valve member 160a which is seated on and off the seat 2, and a holding member 26 which holds the annular rubber valve member 160a and receives the biasing force of the valve spring 160b
And 0a form a valve body. Holding member 260a
The notch 360a in the outer peripheral portion is for forming a passage. When a part of the valve body is formed of a rubber member as in the example of FIG. 4, compared with the case of forming a metal valve body-metal valve seat in the ball valve body 60a, a so-called metal seal, Although it is necessary to increase the diameter, the valve spring 160b
The necessary and sufficient sealing force can be obtained even if the urging force due to is small (the valve opening pressure is set low). For example, even if some foreign matter is caught in the seal part, the seal will not be defective. . The opening of the recess 161 has a plug member 1 for holding the valve element in the recess 161 of the housing.
60c, and the plug member 160c itself is prevented from coming out of the recess 161 by the annular metal member 168. Here, the shaft member 26 is attached to the plug member 160c.
0c, and when the plug member 160c is set in the recess 161, the shaft portion 260c thereof projects from the opening of the recess 161 to the outside of the housing. The protruding shaft portion 260c facilitates attachment / detachment work of the check valve 160.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a brake pressure control valve device 10 that is an embodiment of the present invention.

FIG. 2 is a diagram showing a specific configuration of a brake pressure control valve device 10 shown in FIG.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a partial cross-sectional view showing another example of the check valve.

[Explanation of symbols]

 12 inlet 13 outlet 14 exhaust port 20 holding valve 21b communication passage 25 pilot pressure chamber 30 exhaust valve 35 pilot pressure chamber 52 first control valve 53 second control valve 60 check valve 64 through hole 66 auxiliary passage

Claims (4)

[Claims] 1. A valve is provided between an inlet connected to a brake valve and an outlet connected to a brake actuator, and is urged to a closed position by receiving pilot pressure, and when the pilot pressure disappears, the inlet is closed. Side holding valve which is opened by receiving pressure on the side or outlet side, and an exhaust port which is connected to the outlet and the atmosphere, and is biased to a closed position by receiving pilot pressure, An exhaust valve that opens by receiving pressure on the outlet side as the pilot pressure disappears, and the pilot pressure from the position where the pilot pressure chamber of the holding valve communicates with the exhaust port based on a brake holding signal from the outside. A first control valve that switches to a position for supplying pilot pressure to the chamber and a pilot pressure chamber for the exhaust valve based on a brake slack signal from the outside. A brake pressure control valve device for an air brake, comprising: a second control valve that switches from a position for supplying lot pressure to a position for communicating the pilot pressure chamber with the exhaust port, wherein the first control valve and the exhaust port are provided. Is provided with an auxiliary passage that connects the communication passage to the inlet side, and the auxiliary passage is normally closed, but is opened in response to an increase in internal pressure on the communication passage side from the communication passage side of the exhaust port. A brake pressure control valve device for an air brake system, which is provided with a check valve that allows air movement toward the inlet. 2. The pilot pressure supplied to each pilot pressure chamber of the holding valve and the exhaust valve is used as a brake pressure introduced to the inlet, and each of the first and second control valves includes a pilot pressure. The brake pressure control valve device for an air brake system according to claim 1, wherein a position for supplying a pilot pressure to the chamber is a position where the pilot pressure chamber is cut off from the exhaust port and communicated with the inlet. 3. The brake for an air brake system according to claim 2, wherein a communication passage between the pilot pressure chamber of the exhaust valve and the inlet via the second control valve is also used as a part of the auxiliary passage. Pressure control valve device. 4. The housing of the brake pressure control valve device is formed with a recess opening to the outside in addition to the inlet, the outlet, and the exhaust port, and the check valve is externally provided in the recess. The brake pressure control valve device for an air brake system according to any one of claims 1 to 3, which is detachably incorporated.