JPH072076A - Flow control valve of anti-lock brake device - Google Patents

Abstract

PURPOSE:To provide a flow rate control valve which possesses the high reliability at a low cost by averting the trouble accompanied with the sticking of a spool by providing the self shift action to the spool without adding members, as for the flow rate control valve used for an antilook brake device. CONSTITUTION:A spool 206 generates a communication state in one small passage at a stop position between a B-chamber and a C-chamber, and generates a closure state at the shift position by the first prescribed quantity Lo. Further, at the shift position by the second prescribed quantity, a communication state is generated in the other large passage. Accordingly, a selector valve part 312 is formed between the spool 206 and a sleeve 200. Accordingly, the spool 206 shifts by itself in the sleeve 200 by the pressure difference generated at both the edges in each brake application.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve of a device for controlling re-braking of an antilock brake for automobiles.

[0002]

2. Description of the Related Art Anti-lock brake devices for automobiles have come into widespread use, and there are increasing demands for improved reliability and price reduction. One of the answers to this is, for example,
As disclosed in JP-A-2-88350,
There is one solenoid valve system for each wheel.

Such a conventional technique has a casing having at least two ports, an inlet communicating with a pressure source and an outlet communicating with a wheel brake, and a liquid passage including an orifice. A spool that is slidably inserted and that can switch the communication state between the two ports and a spring that biases the spool in one direction is provided. When the antilock is inactive, the spool is in the inactive position. There is formed a large flow path connecting the inlet and the outlet, the spool is positioned at the re-pressurization point to close the large flow path when the anti-lock is re-pressurized, and the space between the inlet and the outlet is In a flow rate control valve that forms a small flow path that communicates via an orifice, both ends or at least one end receives brake fluid pressure from a pressure source, and the other end receives a force of a biasing means, respectively. Axially by the difference The movable member provided to ride, in which by operating at every braking the movable member was to cause relative movement between the housing and the spool.

[0004]

In the above prior art, the movable body is operated each time the driver depresses the brake pedal, that is, every braking, so that the spool cannot be locked due to the sticking of the spool, poor braking, and antilock. It tries to avoid problems such as outages, but still improvements,
There is room for improvement.

That is, in order to move the spool for each braking, a member (movable body) as a moving body is newly added. Therefore, the cost efficiency is reduced, and the dimension is increased in the axial direction. In addition, there are problems in wear of the ○ ring portion and ensuring of sealing performance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a flow control valve of low cost and high reliability, which enables self-movement of a spool without adding special parts. And

[0007]

SUMMARY OF THE INVENTION The present invention relates to a flow control valve used in an antilock brake device. The flow control valve includes a valve body having an inlet passage communicating with the master cylinder, an outlet passage communicating with the wheel cylinder, and an outlet communicating with the normally closed solenoid valve, and the inlet passage slidably inserted into the valve body. A spool capable of switching between a communication state and an interruption state between the outlet passage and the discharge port, a cover for enclosing the spool in the valve body, and a spring for urging the spool in one direction, and the communication between the inlet passage and the inlet passage Anti-decompression chamber (A chamber) that is formed of the flow path portion of the spool, and a decompression chamber (B that is formed of the flow path portion of the spool that is in communication with the discharge port and that accommodates the spring.
Chamber), a chamber C communicating with the outlet passage and formed of a flow path portion excluding chambers A and B, and a spool at a stop position during normal braking to form a large flow path connecting chambers A and C. At the time of increasing the pressure of the anti-lock, the spool is arranged so as to be located at the pressure increasing point, close the large flow passage, and form a small flow passage communicating between the chamber A and the chamber C via the fixed throttle. The present invention relates to the improvement of the flow control valve.

According to one aspect of the present invention, a small passage through which the brake fluid can flow in and out between the B chamber and the C chamber during normal braking, and the brake fluid from the C chamber to the B chamber when the antilock pressure is reduced. A large passage that can flow to the chamber is provided between the B chamber and the C chamber. Further, according to another aspect of the present invention, the small passage and the large passage are provided in a spool.

In this representative example, in the stop position, the spool establishes a communication state between the chambers B and C by a small passage, and in the closed position where the first predetermined amount is moved, the spool between the chambers C and C is moved. A switching valve portion is formed between the spool and the sleeve so as to be in the communication state again by the large passage in the closed state and at the position further moved by the second predetermined amount.

According to another aspect of the present invention, the small passage and the large passage may be provided in the valve body,
Alternatively, it may be provided on the sleeve.

[0011]

When the brake is not operated, the chamber A communicates with the master cylinder, the chamber B communicates with the solenoid valve, and the chamber C communicates with the wheel cylinder. The spring biases the spool from the B chamber direction toward the A chamber direction.

When the braking operation is performed in this state, the pressure in the A chamber communicating with the master cylinder first rises. When the pressure exceeds the spring force, the spool moves in the B chamber direction. At this time, the brake fluid in the B compartment is pushed out to the wheel cylinder side. This operation continues and the spool moves to the closed position where the switching land provided on the spool closes the communication state between the chamber B and the wheel cylinder side. At this point, room B is in a closed room state. After that, the pressures in chamber A and chamber B are balanced and the spool does not move.

When the braking operation is completed, the pressure in the chamber A decreases, and the pressure in the chamber B and the spring force cause the spool to return to the original stop position.

As described above, the spool can be self-moved from the stop position to the closed position by the pressure difference generated at both ends for each braking.

As described above, each time the driver depresses the brake pedal, the spool moves by itself, so that the problem that the spool does not move for a long time and sticks can be solved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Overall Configuration First, the overall configuration of an embodiment of the present invention will be described with reference to FIG. Braking is started by the driver stepping on the brake pedal 1, and a pressure proportional to the pedaling force is generated in the master cylinder 2. This pressure is transmitted to the hydraulic unit 4 by the conduits 3a and 3b. The passages from the conduits 3a and 3b are further branched into three directions inside the hydraulic unit 4. Only the components related to the conduit 3a will be described below.

The passage after the conduit 3a includes a return passage 5a,
It is branched into inlet passages 8a and 8b connected to the flow control valves 7a and 7b corresponding to the wheels 6a and 6b. The passages from the flow control valves 7a and 7b are connected to the outlet passages 10a and 10b connected to the wheel cylinders 9a and 9b of the wheels 6a and 6b.
b and the discharge ports 11a and 11b for reducing the pressure of the wheel cylinders 9a and 9b during the antilock brake control. Solenoid valves 12a and 12b that are always closed are connected to the discharge ports 11a and 11b. The passages from the solenoid valves 12a and 12b are merged into the same passage 13a. In the same passage 13a, a reservoir 14 for temporarily storing the brake fluid whose pressure is reduced during antilock brake control
a and a pump 15a for returning the brake fluid to the master cylinder 2 via the return passage 5a are connected.

Next, signals and control system relating to antilock brake control will be described. The slip state of the wheels 6a, 6b is determined by the wheel speed sensors 100a, 10 provided on the wheels.
0b is detected and sent to the control device 101. The control device 101 controls the solenoid valves 12a and 12b and the motor 102 of the pump 15a. Next, the operation of the flow rate control valve will be described in detail below with respect to the flow rate control valve 7a only, since each valve is the same.

Structure of Flow Control Valve FIG. 2 is a sectional view of a flow control valve showing an embodiment of the present invention. The stop position state in which no pressure is generated in the master cylinder 2 is shown. The flow control valve 7a has an inlet passage 8a.
And valve body 16 having outlet passage 10a and outlet 11a
a, the sleeve 200, the O-rings 201, 202, 203 for forming passages around the sleeve 200, and the filter 20 relating to the inlet passage 8a and the outlet passage 10a.
4, 205 and the spool 2 sliding in the sleeve 200
06, a spring 207 that biases the spool 206 to the left, and a cover 208.

Next, the passage structure will be described. The passage from the master cylinder 2 is from the inlet passage 8a to the radial inlet passage 300 of the sleeve 200 and the spool 206.
To the first annular groove 301 of the spool 206, the passage 3
02, the passage 303, the passage 304, and the second annular groove 305 to reach the sleeve 200 again. From this point, it communicates with the outlet passage 10a through the radial outlet passage 306 and the outer peripheral annular groove 310 provided in the sleeve 200.
Brake fluid is supplied from the master cylinder 2 to the wheel cylinders 9a through these passages.

A pressure reducing port 30 is provided on the right side of the sleeve 200.
7 is formed, and a switching land 308 is formed on the outer circumference of the spool 206 facing the pressure reducing port 307. A small diameter portion 309 is provided on the right side of the switching land 308, and the discharge port 1 that normally communicates with the solenoid valve 12a is provided.
Decompression port 30 drilled from 1a into sleeve 200
7, a small passage 405 is formed through the outer peripheral annular groove 310 and the outlet passage 10a leading to the wheel cylinder 9a. On the other hand, to the left of the switching land 308, the spool 2
A third annular groove 311 of 06 is formed. And
Normally, since the switching land 308 and the pressure reducing port 307 face each other, the discharge port 11a to the third annular groove 31 are opposed to each other.
The large passage 406 leading to the decompression port 307 via 1 is closed. The switching valve portion 312 according to the present invention includes the pressure reducing port 307, the switching land 308, and the small diameter portion 30 described above.
9 and a third annular groove 311. Next, the operation will be described.

Operation During Normal Braking FIGS. 3 and 4 show an enlarged state of the switching valve portion 312 of the embodiment shown in FIG.

The explanation of the symbols of the respective parts is as follows.

L: width of the switching land 308
(Eg L = 1.4 mm) Lp: Axial dimension of the decompression port 307 (eg L
p = 0.6 mm) Lo: Normal communication size of the outlet passage 10a and the discharge port 11a This is defined as the first predetermined amount. (For example, Lo = 0.
2 mm) Lc: Closed size of the outlet passage 10a and the discharge port 11a at the normal time This is defined as a second predetermined amount. (For example, Lc = 1.
0 mm) Normally, it is in the state shown in FIGS. When the driver depresses the brake pedal to start braking, the flow control valve 7a
A pressure is generated in the entrance passage 8a. The pressure presses the spool 206 rightward (toward the discharge port 11a). At this time, the chamber B on the right side of the spool communicates with the outlet passage 11a with a size of Lo, and the pressure is lower than that of the chamber A. Therefore, the spool 206 is pressed by the pressure from the direction of the A chamber
Is pushed toward room B and moves.

As shown in FIG. 4, the operation of the spool 206 is such that the spool 206 moves a dimension corresponding to the first predetermined amount Lo, and the switching land 308 causes the pressure reducing port 30 to move.
Continue to the closed position where 7 is closed. Then, as shown in FIG. 4, when the chamber B on the right side of the spool 206 is in the closed chamber state and is in a non-compressed state with respect to the pressure increase in the chamber A, the spool 206 does not move any more. When the pressure is generated in the master cylinder 2 and the brake fluid flows into the flow control valve 7a as described above, the spool 206 always moves the first predetermined amount Lo from the stop position shown in FIG. 3 and is shown in FIG. It will move to the closed position.

On the other hand, when the foot is released from the brake pedal, the pressure in the master cylinder 2 drops and the pressure in the chamber A drops. Along with this, the spool 206 is returned to the initial stop position by the pressure of the chamber B and the force of the spring 207. Therefore, for each braking, the spool 206 repeats the self-reciprocating reciprocating operation from the stop position to the closed position in a dimension corresponding to the first predetermined amount.

Further, even if the spool 206 moves by an amount corresponding to the size of Lc-Lo shown in FIG. 4, the switching land 308 keeps the passage closed. This causes the spool 206 to overshoot and re-establish communication between the third annular groove 311 and the pressure reducing port 307.
This is to prevent 06 from moving too much.

Operation of antilock during decompression If a slip phenomenon occurs on any wheel during braking,
The anti-lock brake control is performed by the wheel speed sensor provided on each wheel. For example, a state in which the wheel 6a slips will be described.

When a slip is detected by the wheel speed sensor 100a, the slip signal is sent to the control device 101,
Predetermined calculation and processing are executed in the control device 101. Then, the pressure reducing operation for reducing the pressure of the wheel cylinder 9a is executed to eliminate the slip state. This is executed by opening the solenoid valve 12a in FIG. 1 according to a command from the control device 101. When the solenoid valve 12a is opened, a passage is formed from the discharge port 11a to the reservoir 14a through the same passage 13a. The subsequent operation will be described with reference to FIGS.

When the solenoid valve 12a is opened, the brake fluid is discharged to the reservoir 14a.
The pressure in the room drops. Along with that, the pressure in the chamber A on the left side overcomes the force of the spring 207 and the spool 206
To the right. Then, as shown in FIG. 5, a pressure reducing passage from the wheel cylinder 9a to the outer peripheral annular groove 310, the pressure reducing port 307, the third annular groove 311, and the discharge port 11a is formed. Since the brake fluid is discharged through this pressure reducing passage, the wheel cylinder 9 in the overpressure state
The pressure of a can be reduced.

The depressurizing passage is formed only when the spool 206 moves the second predetermined amount Lc from the initial stop position.

Further, during the depressurizing operation, as shown in FIG. 5, the spool 206 moves to bring the second annular groove 305 of the spool 206 and the radial outlet passage 306 of the sleeve 200 into a closed state. At this point, the direct communication between the master cylinder 2 and the wheel cylinder 9a is cut off,
The decompression operation is alleviated.

When the depressurizing operation further proceeds, as shown in FIG. 6, the right end surface of the spool 206 hits the valve body 16a and is restrained. (This state is referred to as a restrained position state.) This is to prevent the spool 206 from moving too much and closing the pressure reducing passage formed of the pressure reducing port 307 and the third annular groove 311.

The brake fluid discharged via the electromagnetic valve 12a is temporarily stored in the reservoir 14a. After that, the motor 102 and the pump 15a are operated by a command from the control device 101, and returned to the conduit 3a side via the return passage 5a.

When the anti-lock pressure increases When the pressure reducing operation is continued and the slip state of the wheels 6a tends to be eliminated, the solenoid valve 12a is closed by the control of the control device 101. The anti-brake control shifts to the pressure increasing operation as shown in FIG. 7 when the solenoid valve 12a is closed. By closing the solenoid valve 12a, the spool 2
06 starts moving to the left due to the force of the spring 207.
And the radial inlet passage 300 and the first annular groove 301
This movement is performed up to the position where the variable diaphragm portion 402 is formed. During this time, the brake fluid is supplied for pressure increase control.

The passage state of FIG. 7 will be described. FIG. 7 shows a state in which the variable throttle portion 402 is formed by the radial inlet passage 300 and the first annular groove 301, and the direct passage to the wheel cylinder 9a is blocked. At this time, the radial outlet passage 306 is closed, but the fixed restrictor 40 provided in the second annular groove 305 and the sleeve 200 is closed.
The brake fluid flows from the chamber A to the wheel cylinders 9a because the 0 passage is in communication. That is, the passages involved in increasing the pressure of the wheel cylinder 9a are formed. In addition, the chamber A and the chamber B are the fixed throttle 400 and the decompression port 3.
However, the communication between the chamber A and the chamber B is not directly involved in the pressure increasing operation. Next, the operating state will be described.

When the variable throttle 402 is closed, the brake fluid in the chamber A is discharged from the fixed throttle 400 to the wheel cylinder 9a. After that, when the pressure in the chamber A decreases due to this discharge, the spool 206 is pushed leftward by the spring 207 to open the variable throttle portion 402. Then,
Brake fluid is supplied from the master cylinder 2 to chamber A,
The pressure in chamber A rises. Then, the spool 206 moves to the right and closes the variable throttle portion 402 again. At the next moment, the brake fluid is discharged from the chamber A to the wheel cylinder 9a. This operation is repeated.

Therefore, a differential pressure corresponding to the force of the spring 206 is generated at both ends of the spool 206, and the supply flow rate passing through the fixed throttle 400 is determined by this differential pressure and the passing area of the fixed throttle 400. The flow rate becomes constant, and the re-braking of the antilock brake is controlled at this constant flow rate. This operation is performed until the pressures on the master cylinder 2 side and the wheel cylinder 9a side become equal.

When the slip state is again brought about during the pressure increasing operation, the pressure reducing operation described above is started, and the antilock brake control is terminated when the slip state is completely avoided.

Note that, unlike the embodiment shown in FIG. 2,
The small passage, the large passage, and the switching land are spool 20
It may be provided on the sleeve 200 side instead of the 6 side. In that case, the operation is the same as that described above, and the description thereof will be omitted.

[0042]

According to the present invention, the self-moving action of the spool can be achieved without adding a separate member.
It is possible to provide a highly reliable flow control valve having a small number of parts, low cost, and free from problems associated with spool sticking.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram including a flow control valve showing an embodiment of the present invention.

FIG. 2 is a detailed sectional view of a flow control valve showing an embodiment of the present invention.

FIG. 3 is a detailed cross-sectional view of a switching valve unit in a stopped position state.

FIG. 4 is a detailed cross-sectional view of the switching valve unit in a closed position.

FIG. 5 is a detailed cross-sectional view of the flow control valve in the operation of antilock during depressurization.

FIG. 6 is a detailed cross-sectional view of the flow control valve in a restrained position.

FIG. 7 is a detailed cross-sectional view of the flow control valve in the operation of increasing the pressure of the antilock.

[Explanation of symbols]

1 ... Brake pedal 2
..Master cylinders 3a, 3b..Conduit 4
..Hydraulic unit 5a ..Return passages 6a and 6b
..Wheels 7a, 7b ..Flow control valves 8a, 8b
..Inlet passages 9a, 9b ..Wheel cylinders 10a, 10b
..Exit passages 11a and 11b .... Discharge ports 12a and 12b
..Solenoid valve 13a..Same passage 14a
..Reservoir 15a..Pump 16a
..Valve element 100a, 100b .. Wheel speed sensor 101 .. Control device 102 .. Motor 200..Sleeve 201 .. ○ ring 202 .. ○ ring 203 .. ○ ring 204 .. Filter 205 .. Filter 206 .. -Spool 207-Spring 208-Cover 300-Radial inlet passage 301-First annular groove 302-Passage 303-Passage 304-Passage 305-Second annular groove 306-Radial direction Outlet passage 307 · Decompression port 308 · Switching land 309 · Small diameter portion 310 · Outer circumferential annular groove 311 · Third annular groove 312 · Switching valve portion 400 · Fixed throttle

Claims (5)

[Claims] 1. A valve body having an inlet passage communicating with a master cylinder, an outlet passage communicating with a wheel cylinder, and an outlet communicating with a normally closed solenoid valve; and an inlet passage slidably inserted into the valve body, An anti-decompression chamber comprising a spool capable of switching between a communication state and a cutoff state between the outlet passage and the discharge port, the inlet passage and the flow passage portion of the spool communicating with the inlet passage, the discharge port and the discharge port Communicating with the decompression chamber consisting of the flow path part of the spool, and communicating with the outlet passage A
Chamber C, which consists of the flow passages excluding chamber B and chamber B, forms a large flow path that connects chambers A and C with the spool in the stop position during normal braking, and the spool increases when antilock pressure is increased. It is located at the pressure point and closes the large flow path, and the chambers A and C
In a flow control valve of an anti-lock brake device configured to form a small flow path that communicates between the chambers via a fixed throttle, brake fluid may flow between the B chamber and the C chamber during normal braking. A small flow path that can be formed, and a large passage through which the brake fluid can flow from the C chamber to the B chamber when decompressing the antilock is provided between the B chamber and the C chamber. Control valve. 2. The flow control valve according to claim 1, wherein the small passage and the large passage are provided in the spool itself. 3. The flow control valve according to claim 2, wherein the spool is in a communication state between the chamber B and the chamber C by the small passage in the stop position, and the spool is in the closed position after moving the first predetermined amount. A switching valve portion is formed between the spool and the sleeve so that the chamber and the chamber C are closed and the second passage is moved by the second predetermined amount so that the large passage allows communication again. Flow control valve for anti-lock brake device. 4. The flow control valve according to claim 1, wherein the valve body is provided with the small passage and the large passage. 5. The flow control valve according to claim 1, wherein the small passage and the large passage are provided in a sleeve.