JP2998524B2 - Anti-skid device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid device for a vehicle, and more particularly to an improvement in an actuator for the anti-skid device.

[0002]

2. Description of the Related Art An anti-skid brake system (ABS) for controlling brake fluid pressure of a vehicle is effective in avoiding wheel lock during braking on a low μ road or the like. As an actuator in the system, there is an actuator described in Japanese Patent Application Laid-Open No. 2-267064 (Document 1). In this case, a two-position valve is provided as an electromagnetic valve, and necessary control for the brake fluid pressure control is performed by a controller. No. 4
There is also one described in the specification of 715666 (Reference 2).

[0003]

However, in the case of the above-mentioned anti-skid device, in the case of Document 1,
Although one solenoid valve is used per channel, the solenoid valve is a three-port two-position valve (see FIG. 2 of the same document). In the case of Document 2, the discharge valve of the electromagnetic control is switched and controlled by a controller. In this case, one solenoid valve is provided for each channel, but a flow control regulator valve fitted with a spool is used (see, for example, Japanese Patent Application Laid-Open No. H11-157556). Document FIG1). That is, in this case, the ABS actuator has a structure having a flow control valve having such a spool valve as a constituent element.

[0004] As described above, in order to perform anti-skid control, it is necessary to provide a three-port solenoid valve for each channel, or to use a spool valve as described above in addition to the solenoid valve. A flow control valve is required, and as a result, all of them have problems such as a high cost due to a complicated structure. Especially 3 channels,
In the case of a four-channel ABS, an actuator is provided for each brake system of each channel. Therefore, if such a complex and costly actuator is used for each channel, an anti-skid device to be mounted on the vehicle will be used accordingly. The cost is high.

On the other hand, as a solenoid valve to be used, a 2-port 2
It is conceivable to use a position valve (Japanese Unexamined Patent Application Publication No.
44261 (Reference 3)), however, if the system is configured to have two solenoid valves per channel,
This is also complicated and expensive.
Similarly, in the case of an ABS of a four-channel type or the like, two solenoid valves to be controlled by the controller are required for each channel, and the structure is also complicated, and the control for many solenoid valves is also required. The cost is high, including the content. Therefore, it is difficult to obtain an inexpensive anti-skid device with a simple structure.

[0006] The present invention has been improved from such a point,
An object of the present invention is to provide an anti-skid device capable of performing anti-skid control by depressurization and gradual pressure increase, and realizing the anti-skid control with a simple and inexpensive configuration.

[0007]

According to the present invention, the following anti-skid device is provided. That is, the brake pressure is transmitted to the wheel cylinder by a system that communicates a pressure source that generates a brake operating force corresponding pressure with the wheel cylinder. During anti-skid control, the brake oil of the wheel cylinder is guided to a reservoir to reduce the pressure. An anti-skid device for returning accumulated brake oil to said pressure source side by a pump for use in increasing pressure, wherein said solenoid valve is operated to guide wheel cylinder brake oil to said reservoir to reduce wheel cylinder pressure. When,
A first throttle which generates a pressure difference between the pressure source and the wheel cylinder when the wheel cylinder pressure is reduced by operation of the solenoid valve; and a wheel cylinder after the pressure reduction formed by the pressure difference. A switching valve having a second throttle that narrows the communication between the pressure source and the wheel cylinder for gradual pressure increase of the pressure source, the switching valve having a member that moves by a differential pressure caused by the first throttle, A port for communicating the pressure source with the wheel cylinder, wherein when the wheel cylinder pressure is reduced by operation of the solenoid valve, the moving member is moved by the differential pressure of the first throttle, and the member moves. The anti-skid device is characterized in that when the port is closed, the second throttle is formed for slowly increasing pressure.

[0008]

[Function] At the time of anti-skid control, the brake oil of the wheel cylinder is led to the reservoir to reduce the pressure, and the brake oil is returned from the reservoir to the pressure source side by the pump and used for pressure increase. In the anti-skid device of the present invention, the solenoid valve for guiding the brake oil of the wheel cylinder to the reservoir to reduce the wheel cylinder pressure may be one solenoid valve per channel, and the solenoid valve used is a two-port two-position solenoid valve. Suffices, and when the solenoid valve operates, the corresponding wheel cylinder is depressurized, and at the same time, a first throttle which creates a pressure difference between the pressure source and the wheel cylinder; The switching valve that switches the communication with the second throttle to the communication with the second throttle gradually reduces the wheel cylinder pressure. It is boosted. Here, the switching valve is
A member that moves at a pressure difference between the pressure source and the wheel cylinder when the wheel cylinder pressure is reduced by the operation of the solenoid valve, the pressure restriction being generated by a first throttle, and the pressure source and the wheel cylinder The port further communicates with the port, and when the pressure of the wheel cylinder is reduced by the operation of the solenoid valve, the moving member is moved by the differential pressure by the first throttle, and the port moves slowly when the member moves and closes the port. The second throttle for pressure boosting is formed.

Therefore, anti-skid control by depressurization and gradual increase in pressure can be realized with a simple structure in which the pressure is reduced as described above and the wheel cylinder pressure is gradually increased. Make it possible to get In this case, according to the present invention, the first throttle for generating the differential pressure and the second throttle for gentle pressure increase by reducing the communication between the pressure source and the wheel cylinder are separately provided. Can be independently provided as a stop, and the degree of the stop can be determined separately, and can be set to the respective optimum stop. When the cylinder is depressurized, it can function as a pressure difference between the pressure source and the wheel cylinder at the same time as the depressurization of the wheel cylinder pressure, and by the movement of the member moving by the differential pressure by the first throttle, The second throttle formed when the port for communicating the pressure source with the wheel cylinder is closed also has a degree of pressure increase to be gradually increased, and accordingly, a pressure reduction and gentle pressure increase to be realized. As to match the anti-skid control by return, it is possible to realize the slow pressure increase.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention.
Only the brake pressure control system related to the individual wheels is shown. This is for the sake of clarity of the explanation,
In the case of a channel type anti-skid system, a brake pressure control system having the same actuator configuration according to the present embodiment exists for the other three wheels of the vehicle.

In the drawing, 1 is a brake pedal, 2 is a master cylinder (M / C), 3 is a wheel, and 4 is a wheel cylinder (W / C) of the wheel. The brake hydraulic system from the master cylinder 2 to the wheel cylinder 4 is configured as follows.

An output port of the master cylinder 2 for generating a pressure corresponding to the depression of the brake pedal 1 is connected to a brake hydraulic system related to the wheel cylinder 4 of the wheel 3. The circuit portion denoted by reference numeral 100 surrounded by a dashed line in the drawing constitutes an anti-skid (ABS) hydraulic circuit. This comprises one switching valve 5 per channel and one solenoid valve 6 per channel. Here, the reservoir 7, the motor 8 and the pump 9, the check valve 1
0 is included. These are connected to a pipe as shown to form a hydraulic circuit 10.

That is, the oil passage (piping) 100 from the master cylinder 2 is connected to the switching valve 5, and the switching valve 5 is connected to the wheel cylinder 4 via the oil passage 102.
The switching valve 5 in the middle of the pipe connecting the master cylinder 2 and the wheel cylinder 4 has a housing 51 in the illustrated example.
And a piston 52 that moves up and down in the housing 51 in the figure, and a spring 53 that urges the piston 52. The housing 51 has a port 54, a port 55, and a port 57. Is provided.

The piston 52 of the switching valve 5 normally presses the inside of the housing 51 upward in FIG. The interior of the housing 51 is divided by a piston 52 into two chambers, an upper chamber 58 and a lower chamber 59 in the figure. As for the three ports of the housing 51, the port 54 and the port 55 are arranged facing the chamber 59 formed by the piston 53 being at the upper limit position under the normal force of the spring 53 as shown in the figure, A port 57 is arranged facing the other chamber 58 side.

The port 54 facing the chamber 59 of the housing 51 is connected to the oil passage 101 on the master cylinder side. Similarly, the port 55 facing the chamber 59 faces the rod end of the piston 52 in this embodiment. In this position, the housing 51 is formed on the housing 51 and connected to the oil passage 102 on the wheel cylinder side, and these are communicated in the above state. On the other hand, the port 57 facing the chamber 58 is connected to the oil passage 101 on the master cylinder side. Switching valve 5
When the brake pedal 1 is depressed, the pressure of the master cylinder 2 passes through the port 54, the chamber 59, and the port 55 of the switching valve 5, and further passes through the oil passage 102 when the piston 52 is at the upper limit position shown in FIG. And acts on the wheel cylinder 4 of the wheel 3 in this order.

The port 54 and the port 57 preferably have a throttle as shown in the figure. In the case of a port having an aperture, port 5
Reference numeral 4 denotes a port having a weak aperture, and port 57 is a port having a first aperture that is stronger (smaller in diameter) than the weaker (larger diameter) of the port 54. Such port 5
The strong throttle by 7 causes a pressure difference between the master cylinder 2 and the wheel cylinder 4 when the wheel cylinder 4 is depressurized by the operation of the solenoid valve 6 in the brake fluid pressure control of the anti-skid control, as described later. Can function as

In the present embodiment, as described above, the switching valve 5 includes the port 54, the port 55, and the port 5 having a weak throttle.
There is a port 57 which has a stronger throttle than the weak throttle of 4, and the piston 52 in the housing is preferably located at the tip of its rod, i.
A notch 56 (second stop) is formed in a portion facing 5. FIG. 2 is a perspective view showing the notched state. In this example, the notch 56 at the tip of the rod is provided so that the piston 52 is moved from the position in FIG.
When the port 55 is moved downward against the port 3 to block the port 55, the port 55 functions as a throttle (second throttle) for maintaining a slight communication.
For the downward movement (switching) of the piston 52, a pressure difference generated between the master cylinder 2 and the wheel cylinder 4 is used.

Further, as mentioned above, in the present embodiment, the brake hydraulic system includes a normally closed solenoid valve 6 which normally assumes the position shown in the drawing, and a reservoir 7 for storing brake fluid flowing in by the operation of the solenoid valve 6. A pump 9 driven by a motor 8 and a check valve 10 for returning the brake oil accumulated in the reservoir 7 to a pipe between the master cylinder 2 and the switching valve 5 are constituent elements.

Oil passage 102 connected to wheel cylinder 4
As shown, the branch oil passage 103 and the check valve 10
To the oil passage 101 on the master cylinder side. The oil passage 102 connected to the wheel cylinder 4 is also provided with an oil passage 104 branching from the middle thereof as shown in the drawing, and this is connected to the reservoir 7 through the input / output ports 6a and 6b of the solenoid valve 6. And connected to the suction port side of the pump 9.

Here, one solenoid valve 6 is provided for each channel. When the solenoid valve 6 is OFF, it is located at the first position shown in the figure, disconnecting the input / output ports 6a and 6b, and turning ON the input / output port 6a , 6b to take a second position connecting
2 port 6a, 6b, 2 position solenoid valve. this is,
At the time of the anti-skid operation, it is used to guide the brake oil of the corresponding wheel cylinder 4 to the reservoir 7 to reduce the wheel cylinder pressure. Usually, the closed state shown in the drawing is maintained.
During anti-skid control, the oil passage 1
04 is controlled to be opened and closed.

The pump 9 is connected to the reservoir 7 as described above.
The pump is driven by a motor driven pump which pumps up the brake oil accumulated therein and returns it between the master cylinder 2 and the switching valve 5. The brake oil discharged from the discharge port of the pump is passed through an oil passage 105. The oil is returned to the oil passage 101 on the master cylinder side and is used for increasing the pressure.

In the present embodiment, the master cylinder 2, the wheel cylinder 3, the reservoir 7
A solenoid valve 6 that guides the brake oil of the wheel cylinder 4 to the reservoir 7 to reduce the wheel cylinder pressure, and a solenoid valve 6 that is in the middle of a pipe that connects the master cylinder 2 and the wheel cylinder 4. A switching valve 5 having a first throttle for generating a pressure difference between the master cylinder 2 and the wheel cylinder 4 and a second throttle for switching communication between the master cylinder 2 and the wheel cylinder 4 by switching by the pressure difference; And a pump 9 for pumping the brake oil accumulated in the reservoir 7 and returning it between the master cylinder 2 and the switching valve 5.

The solenoid valve 6 is controlled by the controller 200. A signal from a wheel speed sensor (not shown) for detecting the wheel speed of the wheel 3 is input to the controller 200 (the same applies to the other channel side). Control the opening and closing of Further, drive control for the motor 8 can also be performed by the controller 200.

In the anti-skid device according to the present embodiment having the above-described configuration, during normal braking, a braking force corresponding to the brake pedal force is applied to each wheel of the vehicle. In addition, when the anti-skid is activated, basically, the brake oil in the wheel cylinder 4 of the corresponding wheel is guided to the reservoir 7 to reduce the pressure, and is returned from the reservoir 7 to the master cylinder side by the pump 9 to be used for pressure increase. Skid control is performed. In this case, the wheel cylinder 4
At the same time as the pressure is reduced by the operation of the solenoid valve 6 at the 2-port 2 position provided in the oil passage 104 from the to the reservoir 7, the switching valve 5 is switched, whereby the wheel cylinder pressure is gradually increased with respect to the wheel cylinder 4. The anti-skid control is executed in such a manner that the pressure is reduced and the pressure is increased.

Hereinafter, the operation of the actuator of the present apparatus at the time of normal braking, at the time of pressure reduction in the anti-skid operation, and at the time of pressure increase will be described more specifically in this order.

At the time of normal braking As shown in FIG. 1, in the normal state, the switching valve 5 has its piston 52 at the upper position shown in the figure by a spring 53,
The solenoid valve 6 is in a closed position (normally closed position) as shown.

Now, when the driver depresses the brake pedal 1 for braking, the pressure of the master cylinder 2 increases, and the pressure generated in the oil passage 101 is reduced for each channel from the port 54 of the switching valve 5 to the lower side in the figure. Exits port 55 via side chamber 59, passes through oil passage 102,
Is transmitted to the wheel cylinder 4 and the brake is applied. As described above, the brake pressure is transmitted to the wheel cylinder 4 by the above-described system that connects the master cylinder 2 and the wheel cylinder 4. At this time, the pressure of the master cylinder 2 on the other hand passes through the oil passage 101 and passes through the port 57
To the upper chamber 58 in FIG.
9 and the pressure in the chamber 58 are equal, so that the piston 52 does not move. When the driver releases the brake pedal 1 from the braking state, the wheel cylinder 4
Of the switching valve 5 (port 55 → chamber 59 → port 5)
4) and the master cylinder 2 via the check valve 10
Return to As described above, the braking according to the operation of the brake pedal 1 can be performed.

Basically, as described above,
Here, let us also consider a case where the driver depresses the brake pedal 1 extremely quickly and strongly. At this time, it becomes as follows. That is, when the brake pedal 1 is depressed extremely quickly and strongly, the pressure increase in the chamber 59 is delayed correspondingly due to the restriction of the port 54. On the other hand, the aperture of the port 57 is stronger than the aperture of the port 54 as described above.
The pressure increase on the 8 side is further delayed than the pressure increase on the chamber 59 side. Thereby, in such a case, the switching valve 5 is also provided.
The piston 52 does not move and remains pressed upward in the drawing, so that a normal brake is applied in response to the operation of the brake pedal 1.

At the time of normal braking, braking corresponding to the driver's intention can be performed even if the switching valve 5 of this configuration is between the master cylinder 2 and the wheel cylinder. On the other hand, when the wheel lock tendency is detected by the controller 200 at the time of braking on a low μ road such as a frozen road, for example, brake fluid pressure control is performed so as to avoid wheel lock by rapid pressure reduction and gentle pressure increase.

In such control, each unit in FIG. 1 functions as described below to realize this. In this case, the solenoid valve to be controlled by the controller 200 is connected to one oil path (oil path 10) serving as a return path in each channel.
It suffices to open and close 4). Therefore, it is sufficient to have one 2-port 2-position solenoid valve 6 per channel, and when the solenoid valve 6 is operated, the wheel cylinder 4 is depressurized, and at the same time, A (first) throttle which causes a pressure difference between the master cylinder 2 and the wheel cylinder 4, and a communication between the master cylinder 2 and the wheel cylinder 4 which has a (second) throttle due to the pressure difference. The anti-skid control can be performed by a simple configuration in which the wheel cylinder pressure is gradually increased by the switching valve 5 that switches the pressure.

First, at this time, the following operation is performed. Now, in a case where the braking force acts on the wheels in the above-described brake fluid pressure path, when the controller 200 detects the tendency of the wheels to lock based on the signal of the wheel speed sensor, the controller 2
00 drives the solenoid valve 6 of the corresponding channel for a predetermined time to change from the closed state of FIG. 1 to the open state. Then, the brake oil of the corresponding wheel cylinder 4 quickly passes through the oil passage 102, the solenoid valve 6 in the open state, and the oil passage 104, and quickly enters the reservoir 7.
Accumulate. The wheel cylinder pressure can be rapidly reduced (start of anti-skid control).

Thus, the wheel cylinder 4 at this time is
Of the oil passage 10 on the wheel cylinder side
2, the pressure in the lower chamber 59 of the switching valve 5 connected to the switching valve 5 via the port 55 also decreases, but the pressure in the upstream of the switching valve 5 is delayed due to the restriction of the port 54. On the other hand, due to the (first) restriction of the port 57, the pressure in the upper chamber 58 of the switching valve 5 in the figure remains high at this point. Therefore, a pressure difference occurs between the chamber 58 and the chamber 59, and as a result,
The piston 52 of the switching valve 5 moves to the low pressure side (downward in the figure), and thus the port 55 is blocked by the rod portion of the piston 52 by such switching. In this way, when the solenoid valve 6 is operated to the open state, the wheel cylinder 4 is depressurized, thereby producing the above-mentioned switching pressure difference.

At the time of pressure increase during anti-skid operation At this time, the following is performed. When increasing pressure, controller 2
00 controls the solenoid valve 6 to close. During the above-described pressure reduction control, when the solenoid valve 6 which has been in the open state is closed to the state shown in FIG. Mode. At the same time as closing the solenoid valve 6, the motor 8 is also driven by the controller 200. At this time,
The brake oil accumulated in the reservoir 7 by the pump 9 driven by the motor 8 is pumped up, returned through the oil passage 105 of the return passage, and is subjected to pressure increase.

In this state, the piston 52 of the switching valve 5 blocks the port 55 as described above by the above-described pressure reducing operation, but the piston 52 has a notch 56 at the tip of the rod. The pressure of the wheel cylinder 4 is gradually increased through the notch 56 (second throttle). That is, in this mode, the master cylinder 2
In this case, the communication between the motor and the wheel cylinder 4 is switched to a communication with a throttle. Therefore, the pressure is increased gradually through the throttle, and the wheel cylinder pressure is gradually increased. is there. In this way, with respect to the pressure increase after the pressure reduction, the gentle pressure increase can be realized by the function as described above.

When the wheels are locked again, the solenoid valve 6 is opened to reduce the pressure in the same manner as described above. During the anti-skid operation, the anti-skid control is performed by repeating the rapid pressure reduction and the gentle pressure increase as described above, and the wheel lock is prevented. When the pressure of the wheel cylinder 4 substantially matches the pressure of the chamber 58 of the switching valve 5, the spring 5
By the force of 3, the piston 52 returns to the original position.

According to this embodiment, one channel per channel
When the solenoid valve 6 is operated, the pressure of the wheel cylinder 4 is reduced, and at the same time, a pressure difference is generated between the master cylinder 2 and the wheel cylinder 4 (first). The wheel cylinder pressure can be gradually increased by the throttle and the switching valve 5 for switching the communication between the master cylinder 2 and the wheel cylinder 4 to the (second) throttled communication by the pressure difference. The above-mentioned problem is solved, and an inexpensive anti-skid device having a simple structure can be easily obtained.

For each channel, the solenoid valve 6 to be controlled only needs to be a simple solenoid valve capable of controlling the opening and closing of one oil passage 104, and anti-skid control by rapid pressure reduction and gentle pressure increase is realized. It is possible to use the two ports 6a and 6b in the present actuator. For the piping itself around the solenoid valve 6, a structure using a two-position valve having three ports or using two solenoid valves instead of one is used. As compared with the case of a configuration having such a configuration, the piping portion can be made simpler accordingly. In the case of a four-channel system that requires an actuator for independently adjusting the braking force by judging the slip state for each of the four wheels, in addition to the solenoid valve used for each channel,
The effect of cost reduction is large, including the piping portion, and the system as a whole has a simple structure and is inexpensive.

The control logic for the anti-skid control is simple for the solenoid valve 6 itself, such as simply switching between pressure reduction and pressure increase modes, and the corresponding wheel cylinder pressure is gradually increased. The gradual pressure increase itself is performed on the switching valve 5 side, and is a program (ABS control program) required to be executed by the controller 200 for controlling the solenoid valve 6 of each channel.
Can be simpler. Therefore,
Also in this respect, it can be inexpensive.

In the case of a structure using a spool valve, as described above, the structure is complicated and the cost is high. In addition, when considering the point of the brake fluid used in the vehicle, it is necessary to use a general mineral oil. Therefore, in order to achieve the required anti-skid operation in such a configuration, the spool of the flow control regulator valve is used in order to reduce leakage with low-viscosity brake fluid. Higher processing accuracy is required for the cylinder portion in which the valve and the spool valve slide, which is expensive. In particular, for example, in the case of a four-channel type, an actuator is provided for each brake system of each channel. As a result, if an expensive actuator requiring such high machining accuracy is used for manufacturing and machining as an individual actuator, the more the actuator is mounted, The cost is further increased as a skid device.

In the anti-skid device according to the present embodiment, the switching valve 5 has a simple structure without such disadvantages as compared with a structure using such a spool valve. As for, if the functions described above can be performed at the positions facing the corresponding rooms 58 and 59,
Without requiring high accuracy up to the above level,
In addition, it can be arranged and formed at a desired position of the valve housing without any major restriction, and therefore, it does not require high processing accuracy in its manufacturing process. In this respect, the structure is easily simple and inexpensive. Help to achieve. In particular, in the case of a four-channel system, the effect of cost reduction and the like becomes large as a whole as a whole.

The present invention is not limited to the above embodiment. For example, the present invention is not limited to the case of four channels, and it is needless to say that the present invention can also be applied to three channels in which the front wheel left and right are individually controlled and the rear wheel left and right are commonly subjected to antiskid control.

The present invention can also be implemented in a brake system having a pressure source for generating a brake operation force corresponding pressure according to the brake operation force, instead of the master cylinder, and using the pressure from the pressure source as the original pressure. Also, for example, a preferred example as a switching valve is shown in FIGS. 1 and 2, but the invention is not limited to the illustrated structure.

[0043]

According to the present invention, in order to realize brake fluid pressure control for avoiding wheel lock, the pressure of a corresponding wheel cylinder is reduced by one simple solenoid valve per channel, and after the pressure is reduced, the wheel cylinder pressure is reduced. With a simple configuration for gradually increasing the pressure, anti-skid control can be performed by decompression and gradual pressure increase, and an inexpensive anti-skid device with a simple structure can be obtained. In this case, according to the present invention, the first throttle for generating the differential pressure and the second throttle for gentle pressure increase by reducing the communication between the pressure source and the wheel cylinder are separately provided. Can be independently provided as a stop, and therefore, the degree of the stop is also
The first throttle is determined separately and can be set to a dedicated optimal throttle. When the wheel cylinder is depressurized by the operation of the solenoid valve, the first throttle is simultaneously depressurized with the pressure source and the wheel. The second throttle formed when the port for communicating the pressure source with the wheel cylinder is closed by the movement of the member moving by the differential pressure by the first throttle. Can be realized in accordance with the degree of pressure increase to be gradually increased, and accordingly, anti-skid control by repeating pressure reduction and gentle pressure increase to be realized.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of an anti-skid device of the present invention, and is a diagram showing a configuration of a brake pressure system related to one wheel.

FIG. 2 is a perspective view of a piston portion of the switching valve of the same example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Master cylinder 3 Wheel 4 Wheel cylinder 5 Switching valve 6 Solenoid valve 6a, 6b Input / output port 7 Reservoir 8 Motor 9 Pump 10 Check valve 51 Housing 52 Piston 53 Spring 54 Port 55 Port 56 Notch (second throttle) ) 57 port (first throttle) 101 to 105 oil passage 200 controller

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-95956 (JP, A) JP-A-2-267064 (JP, A) JP-A-4-8656 (JP, A) 44661 (JP, U) Shokai Sho 63-98869 (JP, U) Shokai Hei 2-26967 (JP, U) Japanese Patent Publication No. 3-69742 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 8/48

Claims (1)

(57) [Claims] 1. A brake pressure is transmitted to a wheel cylinder by a system that communicates a pressure source for generating a brake operating force corresponding pressure with a wheel cylinder.
An anti-skid device in which the brake oil of the wheel cylinder is guided to a reservoir to reduce the pressure, and the brake oil accumulated in the reservoir is returned to the pressure source side by a pump to increase the pressure. A solenoid valve which is guided to a reservoir and is operated to reduce the wheel cylinder pressure; and a first valve for generating a pressure difference between the pressure source and the wheel cylinder when the wheel cylinder pressure is reduced by the operation of the solenoid valve. And a switching valve formed by the differential pressure and having a second throttle for narrowing the communication between the pressure source and the wheel cylinder for gradually increasing the pressure of the wheel cylinder after the pressure reduction. Has a member that moves by the differential pressure caused by the first throttle, and further has a port that communicates the pressure source with a wheel cylinder. When the pressure of the wheel cylinder is reduced by the operation of the solenoid valve, the moving member is moved by the differential pressure of the first throttle, and when the member moves and closes the port, the second member for slowly increasing the pressure is moved. anti-skid equipment, wherein the aperture is formed.