JPH09175369A - Air over hydraulic booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air over hydraulic booster equipped with a brake controlling function, with which brake control and disengagement of the brake can be made properly and quickly without causing large-size construction of the device. SOLUTION: When the compressed air in a pressure chamber 11 is to be exhausted, the path via a holding solenoid valve 37 and a brake valve B/V or a path via an exhausting solenoid valve and exhaust port 34 is usually used. Besides these paths for air exhaustion, an exhaust path 40 for brake disengagement is provided according to the present invention. This is a path leading from the pressure chamber 11 to the atmosphere, and a quick release valve 41 is provided on the way of this exhaust path 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-over-hydraulic booster used in a brake system of a vehicle such as a truck or a bus and having a brake control function such as anti-skid control or traction control.

[0002]

BACKGROUND OF THE INVENTION Air over hydraulic boosters are
The pneumatic pressure is converted into a hydraulic pressure, and is provided with a pneumatic operating unit and a hydraulic cylinder unit. The pneumatic operating unit has a pneumatic piston that forms a pressure chamber and a non-pressure chamber in its housing, and the hydraulic cylinder unit has a hydraulic piston that can be interlocked with the pneumatic piston. When compressed air is supplied from the brake valve to the pressure chamber, the pneumatic piston slides toward the non-pressure chamber side accordingly, and the hydraulic piston slides in conjunction with this, generating hydraulic pressure. .

By the way, recently, it is general to add a brake control function such as anti-skid brake control or traction control to a brake system. As means for adding a brake control function to the air-over-hydraulic booster, means for controlling pressure at the pneumatic stage and means for controlling pressure at the hydraulic stage can be considered. Of these, the means for controlling the pneumatic pressure is preferable because it is relatively simple to install and is easy to install. The present invention relates to an air-over-hydraulic booster in which brake control is performed by controlling pneumatic pressure.

An air-over hydraulic booster having the above-mentioned brake control function is disclosed in, for example, Japanese Patent Laid-Open No. 3-16.
As described in Japanese Patent Publication No. 7061, a pressure control valve device for holding or discharging compressed air in the pressure chamber to the atmosphere based on a command from the outside is provided. The pressure control valve device includes two valves, a holding solenoid valve and an exhaust solenoid valve.

The holding solenoid valve is normally in the open state, and the brake is normally applied by passing the compressed air sent from the brake valve side into the pressure chamber. When the brake is released, the pressure on the brake valve side is released, so that the compressed air in the pressure chamber is discharged from the brake valve side to the atmosphere through the holding solenoid valve. At this time, the exhaust solenoid valve remains closed. The same applies when the command from the outside to the pressure control valve device ends and the brake is released. Hereinafter, in this specification, "release the brake" means releasing the brake in the absence of an external command, and releasing the brake after the external command is completed.

On the other hand, the pressure control valve device carries out the following brake control based on an external command. First, the electromagnetic valve for holding is switched to the closed state, and the communication between the brake valve and the pressure chamber is cut off to keep the air pressure in the pressure chamber constant. Then, the electromagnetic valve for exhaust is switched to the open state, the pressure chamber and the atmosphere are connected to relax the air pressure in the pressure chamber. Then, the exhaust solenoid valve is closed, the holding solenoid valve is opened, and compressed air is passed through the pressure chamber. By repeating such valve control, compressed air is repeatedly stored, held and loosened, and proper brake control is performed.

[0007]

As described above, the holding solenoid valve has the function of shutting off the pressure chamber from the brake valve side during brake control such as anti-skid control and traction control based on an external command. Since it also has a function of increasing the air pressure in the pressure chamber, the passage area inside the pressure chamber can limit the boosting speed and the like as desired by giving priority to supplying compressed air rather than discharging compressed air. , The size is suitable for supplying compressed air. Further, in terms of improving the responsiveness during brake control, quick switching between opening and closing is required, so it is possible to reduce the size of the valve plunger (valve body) that strokes according to the excitation / demagnetization of the solenoid coil. Preferably, the area of the passage opened and closed by the valve plunger (valve body) tends to be naturally reduced. Therefore, it cannot be said that the passage area of the holding solenoid valve is sufficiently secured as an exhaust passage for the compressed air, and for pressure release on the brake valve side, from the pressure chamber through the holding solenoid valve to the brake valve. There is a problem that the exhaust of the compressed air to the side is delayed, and thus the release of the brake acting on the wheel is delayed. As a measure to secure a sufficient exhaust passage, when the area of the passage sealed by the valve plunger at the time of closing the valve is increased, the diameter of the valve plunger is increased and the sealing area is affected. It is necessary to increase the exciting force for urging the valve plunger to the closed position by overcoming the air pressure that is generated, and the solenoid coil also becomes large, which causes another problem such as increased power consumption and increased weight. Will occur.

Therefore, the present invention provides a technique in an air-over-hydraulic booster to which a brake control function is added, in which both brake control and brake release can be appropriately and quickly performed without increasing the size of the device. To aim.

[0009]

The above object is achieved by separately providing a brake releasing exhaust passage that connects the pressure chamber and the atmosphere, and exhausting the compressed air in the pressure chamber from the exhaust passage. The brake release exhaust passage is characterized in that it does not pass through the holding solenoid valve. That is, the time required for releasing the brake does not depend on the passage area of the holding solenoid valve, but depends only on the flow passage resistance of the brake releasing exhaust passage. Therefore, the holding solenoid valve can further improve the responsiveness of the brake control without increasing the size of the device. On the other hand, the brake release exhaust passage enables quick brake release.

Normally, a valve is opened in the middle of the brake release exhaust passage so as to prevent compressed air in the pressure chamber from escaping during brake operation (including brake control) and to open to communicate with the atmosphere during brake release. Set up. From the viewpoint of quick exhaust, it is preferable to apply a quick release valve to this valve.

In the air-over-hydraulic booster according to the present invention, the smaller the flow path resistance when the compressed air is discharged to the atmosphere through the brake release exhaust passage, the more quickly the air can be exhausted. Preferably, it is made smaller than the flow path resistance when the compressed air is discharged through the holding solenoid valve. This is because the significance of providing the brake releasing exhaust passage separately in the present invention is enhanced. To reduce the flow resistance, increase the passage area of the quick release valve when it is opened than the passage area of the holding solenoid valve, increase the diameter of the passage itself, shorten the piping, etc. Is mentioned.

The brake release exhaust passage may be provided completely separately, but it is desirable to share a part with the other passage from the viewpoint of downsizing the booster. Specifically, it is preferable that a part of the passage connecting the pressure chamber and the holding solenoid valve be shared, and the passage be branched in the middle. This is because it is possible to promptly respond to the pressure drop on the brake valve side at the time of releasing the brake to prompt the exhaust of the compressed air. If you look at the brake release exhaust passage like this,
It can be said that it is a passage that bypasses the exhaust solenoid valve. This is because both are passages that connect the pressure chamber and the atmosphere.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In order to improve the responsiveness of brake control, in addition to increasing the opening / closing speed of a holding solenoid valve, the piping between the pressure chamber and the pressure valve control device is shortened to reduce transmission loss. Conceivable. The above-mentioned Japanese Patent Laid-Open No.
As described in Japanese Patent No. 167061, there is a method of integrating the base portion of the pressure control valve device with the housing of the pneumatic operating portion. This idea can also be applied to the air over hydraulic booster of the present invention. In this case, in order to reduce the size of the device, at least the quick release valve to the exhaust port in the brake release exhaust passage is preferably provided in the base portion. More preferably,
Install a quick release valve near the exhaust port.
This is because the quick release valve can be incorporated from the exhaust port side, which facilitates manufacturing.

As the quick release valve, various known forms can be applied. Among them, the one which includes a rubber plate member, and the valve is opened and closed by the deformation of the plate member, The structure is simple.

From the viewpoint of reducing the number of parts,
It is preferable that the exhaust port of the brake release exhaust passage also serves as an exhaust port for discharging the compressed air to the atmosphere through the exhaust solenoid valve. In this way, compressed air is discharged from the exhaust port during brake release and brake control. That is, the opportunity for compressed air to flow through the exhaust port increases. Therefore, even if snow adheres to the exhaust port, it becomes easier to remove it due to the circulation of the compressed air, so that the adhered snow is less likely to freeze, and the effect of preventing the exhaust port from closing can also be obtained.

Further, from the viewpoint of facilitating the manufacture, the housing of the pressure control valve device can be formed integrally with the rear end wall of the pneumatic operating portion. In this way, the pipe length can be shortened, the number of parts can be reduced, and the number of seal members can be reduced. At this time, the pressure control valve device is located at the rear end portion of the pneumatic operating portion.

[0017]

EXAMPLES The present invention will be further described below with reference to examples. Incidentally, here, both of them have an anti-skid control function added, and a pressure control valve device is integrated with the housing of the pneumatic operating portion. However, the present invention is not limited to these, and a traction control function may be further added, or the pressure control valve device may be provided separately from the pneumatic operating portion.

<Embodiment 1> This embodiment is an air-over-hydraulic booster in which the pressure control valve device is located above the pneumatic operating portion. FIG. 1 is a sectional view of an air-over hydraulic booster 100 of this embodiment.
The air-over-hydraulic booster 100 includes a pneumatic operating unit 10 that operates by receiving compressed air sent from the brake valve B / V side, and a hydraulic cylinder unit 20 that transmits brake hydraulic pressure to the brake device W / C. And a pressure control valve device 30 that receives a command from the electronic control unit ECU and controls the air pressure to the pneumatic operation unit 10. Such a structure is almost the same as the conventional one. Therefore, first, the structure of each part of the booster, which is the premise of the present invention, will be clarified in order, and then the point of the present invention will be described.

The pneumatic operating portion 10 has a pneumatic piston 17 which is slidable inside the housing 19. The pneumatic piston 17 includes a rod portion 17a extending in the sliding direction,
The pressure receiving portion 17b is located at the rear end (left side in FIG. 1) of the rod portion 17a. The housing 19 is composed of a cup-shaped container body 19b having one end opened and a lid body 19a closing the opening, and the rod portion 1 of the pneumatic piston 17 is formed.
7a penetrates the lid 19a. Inside the housing 19, the pressure chamber 1 to which compressed air from the brake valve B / V is supplied by the pressure receiving portion 17b of the pneumatic piston 17 is provided.
1 and a pressureless chamber 12 which faces the lid 19a and communicates with the atmosphere through the oblique passage 32. A sealing member 13 is provided on the outer periphery of the pneumatic piston 17 to connect the pressure chamber 11 to the pressureless chamber 12
Is cut off from. A pneumatic piston 17 is provided in the pressureless chamber 12.
There is a return spring 18 for urging the pressure chamber 11 toward the pressure chamber 11. An air inlet 16 is provided on the wall surface of the housing 19 facing the pressure chamber 11. Compressed air from the brake valve B / V is supplied to the pressure chamber 11 through the air inlet 16. With the supply of this compressed air, the pneumatic piston 17 moves the return spring 18
It slides to the pressureless chamber 12 side against the urging force of. An overstroke sensor 50 is provided on the wall surface of the housing 19 facing the pressureless chamber 12 to detect the sliding limit of the pneumatic piston 17.

The hydraulic cylinder portion 20 is an axially adjacent portion of the pneumatic operating portion 10. The hydraulic cylinder unit 20 includes a cylinder body 2 having a cylinder hole 21.
2 and the hydraulic piston 2 located inside the cylinder hole 21.
3 and a return spring 24 that pushes the hydraulic piston 23 toward the pneumatic operation unit 10 side. The cylinder body 22 and the hydraulic piston 23 have the same axis as the rod portion 17 a of the pneumatic piston 17. A valve member 25 having a U-shaped cross section is provided at the end of the rod portion 17 a, and the valve member 25 faces the seal ring 26 a on the inner circumference of the hydraulic piston 23. Therefore, the pneumatic piston 17 is located on the hydraulic cylinder portion 20 side (the non-pressure chamber 12).
Side), the valve member 25 causes the seal ring 26
The inner peripheral side of the hydraulic piston 23 is sealed in cooperation with a. Another seal ring 2 is provided on the outer circumference of the hydraulic piston 23.
There is 6b. Therefore, the inner and outer peripheral seal rings 26
The hydraulic chamber 2 is provided inside the cylinder hole 21 by a and 26b.
7 are divided. This hydraulic chamber 27 is provided with the pneumatic piston 17
In response to the movement of the hydraulic piston 23 that is linked to
Increase the hydraulic pressure inside 7. Such hydraulic pressure is applied to port 28.
Is supplied to the brake device W / C through the brake device and the brake operation is performed.

On the other hand, the pressure control valve device 30 is located above the pneumatic operating portion 10 and the hydraulic cylinder portion 20 in FIG. 2 is an enlarged view of a section 2-2 in FIG.
The structure of the pressure control valve device 30 and its peripheral portion is shown. The pressure control valve device 30 is located between the brake valve B / V and the pneumatic operating unit 10. And brake valve B /
A control valve inlet 35 communicating with V, a control valve outlet 36 communicating with the pressure chamber 11 (air inlet 16) of the pneumatic working unit 10,
And an exhaust port 34 communicating with the atmosphere. A check valve 33 is provided at the exhaust port 34 to prevent air from flowing back from the outside atmosphere to the inside. A communication line 66 connects between the control valve outlet 36 and the air inlet 16. The connection port 67 provided in the lid body 19a is one pipe connection portion of the pipe line 66.

In the case of adding not only the anti-skid control function but also the traction control function, the brake valve B / V side of the pressure control valve device 30 is based on a command from the electronic control unit ECU during traction control. A switching valve device (not shown) for disconnecting the control valve inlet 35 from the brake valve B / V and communicating with the air tank is provided.

Inside the pressure control valve device 30, there are two valves, a holding solenoid valve 37 and an exhaust solenoid valve 38 that control the air pressure. The holding solenoid valve 37 is connected to the control valve inlet 35.
It is located in a passage that connects the (brake valve B / V side) and the control valve outlet 36 (pressure chamber 11 side), and the passage is opened or closed by opening and closing the valve. The other exhaust solenoid valve 3
8 is a control valve outlet 36 (pressure chamber 11 side) and an exhaust port 34.
It is located in a passage that communicates with (atmosphere side), and opens or closes the valve to connect or cut off the passage.

In the air hydraulic booster of this type, when the compressed air inside the pressure chamber 11 is exhausted, generally, a passage passing through the holding solenoid valve 37 and the brake valve B / V or the exhaust electromagnetic valve is used. A passage through valve 38 and exhaust 34 is used. In that respect, according to the present invention,
In addition to these exhaust passages, a brake release exhaust passage 40 is provided, and a quick release valve 41 is provided in the passage 40. The brake release exhaust passage 40 is a passage that connects the pressure chamber 11 (air inlet 16) of the pneumatic operating unit 10 and the atmosphere, and includes the above-mentioned connecting pipe 66 in a part thereof. The brake release exhaust passage 40 is connected to the communication pipe 6
6 and a control valve outlet 36 are connected to each other through a branch passage 46 that obliquely branches from a connection port 67 that connects the control valve outlet 36 to the outside atmosphere. As the exhaust port through which the brake release exhaust passage 40 communicates with the atmosphere, it is preferable to use the exhaust port 34 of the pressure control valve device 30. Thereby, the space around the exhaust port can be reduced. Further, in order to prevent the opening from being blocked by snow or the like, the opening is directed downward, or in order to facilitate the attachment of the check valve 33 and the quick release valve 41, the exhaust port 34 has a large diameter on the outside and has an inside diameter. It is also preferable to set the diameter so that it becomes smaller. In the example shown in the figure, the opening of the exhaust port 41 faces downward, and the check valve 33,
A quick release valve 41 is located inside thereof.

FIG. 3 is a sectional view showing the structure and operation of the quick release valve 41. As shown in FIG. 3, the quick release valve 41 has a rubber disc-shaped member 42 that serves as a valve body. The disc-shaped member 42 is located at the back of the exhaust port 34, its outer peripheral edge contacts the lid 19a side, and its central portion is supported by the valve seat member 43 having a cross-section. The valve seat member 43 has a through hole 432 in the center,
An O-ring 434 is provided on the outer circumference, and a through hole 432 is provided.
The valve seat portion 436 is formed around the opening. The through hole 432 located on the lower surface side of the disc-shaped member 42 communicates with the atmosphere through the exhaust port 34. Further, the upper surface side of the disk-shaped member 42 is
It communicates with the holding solenoid valve 37 side through a central hole 47 provided in the lid 19a of the housing 19. Therefore, this central hole 4
7, the disc-shaped member 42 is connected to the brake valve B / V.
It deforms under the pressure from the side and seats on or separates from the valve seat portion 436.

Here, the opening / closing operation of the quick release valve 41 mainly composed of the disc-shaped member 42 will be described. When the brake is not operated, no pressure is applied from the brake valve B / V side through the center hole 47. Therefore, the disk-shaped member 4
2 is a state in which the valve seat portion 436 is lightly ridden as shown in FIG. However, when the brake pedal is stepped on by the driver's operation, the pressure of the compressed air is transmitted from the brake valve B / V side through the center hole 47, as shown in FIG.
As shown in (b), the disc-shaped member 42 is pressed against the side of the through hole 43, and is further deformed so that the outer peripheral edge is separated from the side of the lid 19a. However, even with such deformation,
The disc-shaped member 42 is seated on the valve seat portion 436 and remains closed. Also, when releasing the brake,
The pressure introduced from the brake valve B / V side to the center hole 47 is lower than the pressure introduced from the pressure chamber 11 to the lower outer periphery of the disc-shaped member 42 through the branch passage 46. Then, as shown in FIG. 3C, the disc-shaped member 42 is deformed so as to be pressed against the center hole 47 side, closes the center hole 47, and the lower surface thereof is separated from the valve seat portion 436,
The valve is open.

In order to improve the responsiveness of valve operation, it is preferable to make the length of the pipe as small as possible. From that point of view, the base portion 49 that serves as a mounting base of the pressure control valve device 30 is integrated with the housing 19 of the pneumatic operating portion 10. The base portion 49 is formed integrally with the lid 19a of the housing 19 of the pneumatic operation portion 10 described above. The base portion 49 includes the exhaust passage 4 for releasing the brake.
The quick release valve 41 and the exhaust check valve 33 of 0 are built in. When actually mounting, the quick release valve 41 is first assembled from the opening of the exhaust port 34. To keep airtightness, an O-ring 434 is provided on the outer circumference thereof. Further, the C-ring 45 is used to prevent coming off. Then, the exhaust check valve 33
From the exhaust port 34. It goes without saying that the check valve 33 itself includes a support frame 333 having a hole for ventilation, a rubber plate 332 having an inner periphery supported by the support frame 333, and the like.

Next, the pressure control valve device 3 when the brake is operated (including the brake control) and when the brake is released.
The relationship between 0 and the brake release exhaust passage 40 will be described. When the pressure control valve device 30 is not in operation, the holding solenoid valve 3
7 is in a position where the valve body 37a is separated from the valve seat 37b by the force of the spring 37s due to the demagnetization of the coil and the valve is opened. At this time, the electromagnetic valve 38 for exhaust is in a closed position where the valve body 38a is seated on the valve seat 38b by the force of the spring 38s due to the demagnetization of the coil. When the driver depresses the brake pedal under such a state, the compressed air from the brake valve B / V is controlled valve inlet 35-holding solenoid valve 37-control valve outlet 3
6-connection port 67-communication conduit 66-air inlet 16
The pressure is supplied to the pressure chamber 11, and the brake operates. At this time, since the quick release valve 41 is in the valve closed state as described above, the compressed air flows from the connection port 67 to the branch path 4.
There is no occurrence of a situation in which air is discharged through 6 and so-called air leakage. On the other hand, when the driver releases his / her foot from the brake pedal, the compressed air in the pressure chamber 11 flows backward through the air inlet 16-communication line 66-connection port 67 as the pressure on the brake valve B / V side is released. . At that time, paying attention to the vicinity of the connection port 67, the passage 670 from the control valve outlet 36 to the pressure control valve device 30 is a throttle,
The flow path resistance is large. On the other hand, the branch passage 46 has a large pipe diameter and a small flow passage resistance. Therefore, most of the compressed air is discharged from the connection port 67 through the branch passage 46, the quick release valve 41 and the exhaust port 34 to the atmosphere, and the brake is released. That is, the compressed air in the pressure chamber 11 is discharged to the atmosphere from the brake releasing exhaust passage 40. Here, the fact that the opening diameter of the quick release valve 41 (the diameter of the through hole 432) is larger than the opening diameter of the holding solenoid valve also contributes to the flow of compressed air from the connection port 67 to the branch passage 46.

Further, when the brake is actuated, the pressure control valve device 30 is actuated when the external electronic control unit ECU determines through the wheel speed sensor provided for the wheel that the wheel tends to lock. To do. First, when the electronic control unit ECU outputs a brake holding signal, the holding solenoid valve 37 switches to the closed position based on the signal, and the pressure chamber 11 is shut off from the brake valve B / V.
At this time, the exhaust solenoid valve 38 remains in the closed position. In this state, the air pressure of the pressure chamber 11 is kept constant, and the brake hydraulic pressure of the hydraulic cylinder portion 20 which is interlocked with this is kept constant. Continuing, electronic control unit E
When the CU issues a brake slack signal, the exhaust electromagnetic valve 38 switches to the open position based on the signal, and the pressure chamber 1
1-Exhaust port 34 communicates. In this state, the pressure chamber 1
The compressed air in 1 is discharged to the atmosphere, and the brake hydraulic pressure of the hydraulic cylinder portion 20 is released accordingly. Further, the electronic control unit unit ECU repeats the valve switching control described above based on the state of the wheels to perform appropriate brake control. During brake control, air pressure or atmospheric pressure is transmitted to the disc-shaped member 42 through the center hole 47.
Therefore, the quick release valve 41 is in the state shown in FIG. 3A when the pressure in the pressure chamber 11 is kept constant, and the exhaust solenoid valve 38 is opened to open the pressure chamber 1.
When the pressure of No. 1 is reduced, the state shown in FIG. 3C is reached, and the compressed air in the pressure chamber 11 is also discharged to the atmosphere through the brake release exhaust passage 40.

Thus, when releasing the brake,
The pressure chamber 1 is not passed through the pressure control valve device 30, particularly the holding solenoid valve 37, but through the quick release valve 41.
The compressed air in 1 is quickly exhausted to the atmosphere. Therefore, the responsiveness of the pressure control valve device 30 can be improved, but the quickness of releasing the brake can be secured, and at this time, the device does not become large. In this embodiment, a passage that connects the pressureless chamber 12 and the exhaust port 34 to the base portion 49 is provided to prevent the pneumatic piston 17 from sliding toward the pressureless chamber 12 when the brake is operated. Accordingly, the air in the pressureless chamber 12 is discharged to the atmosphere through the exhaust port 34.
By doing so, the air flows from the exhaust port 34 even when the normal brake is operated. Therefore, in the exhaust port 34, air is frequently circulated during normal brake operation, brake control, and brake release. Therefore, there is an advantage that it is possible to prevent the exhaust port 34 from being blocked by freezing of snow or the like.

<Embodiment 2> In this embodiment, the base portion 24
9 is a container body 21 of the housing 219 of the pneumatic actuator 210.
9b is an example integrated with the rear end wall, that is, the container body 2
19b is an example of a die-cast integrally molded product including the base portion 249. FIG. 4 is a sectional view of this air hydraulic booster. The pressure control valve device 230 is attached to the base portion 249 at the rear of the pneumatic operating portion 210, and the connecting pipe line 66 in the first embodiment can be omitted, and the number of parts and the number of sealing points are reduced accordingly. Therefore, it is possible to reduce the size and improve the mountability. Further, the connecting portion between the pneumatic piston 217 and the hydraulic piston 223 is
It is the same as a known one (for example, the one described in Japanese Patent Laid-Open No. 3-167061). However, other than that, it is the same as that of the first embodiment, and the members corresponding to the first embodiment are denoted by reference numerals with 200 added so that the correspondence can be seen. In this embodiment, the tubing length is extremely short, which makes the brake response quicker.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a section 2-2 in FIG.

FIG. 3 is a sectional view for explaining the operation of the quick release valve in FIG.

FIG. 4 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Air pressure operation part 11 Pressure chamber 12 Non-pressure chamber 20 Liquid pressure operation part 30 Pressure control valve device 34 Exhaust port 35 Control valve inlet 36 Control valve outlet 37 Holding solenoid valve 38 Exhaust solenoid valve 40 Brake release exhaust passage 41 Quick release valve 42 Disc-shaped member (valve body) 43 Valve seat member 46 Branch path

Claims (10)

[Claims] 1. A pneumatic piston is slidably arranged in a housing, a pressure chamber to which compressed air is supplied is formed at one end of the pneumatic piston, and the other end of the pneumatic piston is exposed to the atmosphere. It has a pneumatic working portion forming a non-pressurized chamber connected to it, and a hydraulic piston capable of interlocking with the pneumatic piston, and the hydraulic piston is pressed in response to the supply of compressed air to the pressure chamber. Thus, a hydraulic cylinder portion for generating a brake hydraulic pressure, a holding solenoid valve for cutting off the supply of compressed air to the pressure chamber, and an exhaust gas for discharging the compressed air in the pressure chamber to the atmosphere through an exhaust port. In an air hydraulic booster that includes a solenoid valve and a pressure control valve device that controls the opening and closing of these valves based on a command from the outside, when releasing the brake, the compressed air in the pressure chamber,
An air-over-hydraulic booster, characterized in that it is discharged to the atmosphere through another brake releasing exhaust passage that does not pass through the holding solenoid valve. 2. The air over hydraulic booster according to claim 1, wherein the brake release exhaust passage has a quick release valve in the middle thereof. 3. The air-over-hydraulic booster according to claim 2, wherein the brake release exhaust passage is branched from a midway of a passage connecting the pressure chamber and the holding solenoid valve. 4. The air-over-hydraulic booster according to claim 2, wherein the brake release exhaust passage is a passage that bypasses the exhaust electromagnetic valve. 5. The flow passage resistance when the compressed air in the pressure chamber is discharged to the atmosphere through the brake release exhaust passage is smaller than the flow passage resistance when discharged through the holding solenoid valve. Item 5. The air over hydraulic booster according to any one of items 1 to 4. 6. A base portion for mounting the pressure control valve device is integrated with a housing of the pneumatic operating portion, the base portion including an exhaust port, and the quick release valve disposed inside the exhaust port. Claim 2 is built in.
5. The air over hydraulic booster according to any one of 5 to 5. 7. The air according to claim 6, wherein the exhaust port for exhausting air from the quick release valve to the atmosphere also serves as an exhaust port for exhausting compressed air in the pressure chamber from the exhaust electromagnetic valve to the atmosphere. Over hydraulic booster. 8. The air over hydraulic booster according to claim 6, wherein the quick release valve is incorporated from the exhaust port. 9. The pressure control valve device according to claim 6, wherein the base portion is integrally formed with a rear end wall of the pneumatic operation portion, and the pressure control valve device is provided at a rear end portion of the pneumatic operation portion. Air over hydraulic booster described in any one. 10. The airover according to claim 2, wherein the quick release valve includes a rubber plate member, and the plate member is deformed to close or open the valve. Hydraulic booster.