JP3561357B2 - Anti-lock brake control device for vehicles - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
According to the present invention, a brake fluid pressure control means having an orifice interposed between a master cylinder and a wheel brake and capable of controlling a communication state of the wheel brake with the master cylinder and the reservoir between the master cylinder and the wheel brake is provided. The present invention relates to an antilock brake control device for a vehicle provided.
[0002]
[Prior art]
Conventionally, in such an antilock brake control device, the orifice of the brake fluid pressure control means communicates between the master cylinder and the wheel brake to increase the brake fluid pressure during the antilock brake control in which the wheel brake fluid pressure is reduced. This is provided to prevent a sudden increase in the brake fluid pressure of the wheel brakes when in the state. However, the presence of the orifice suppresses the output hydraulic pressure of the master cylinder from immediately acting on the wheel brake during a normal brake operation, and delays the increase in the brake hydraulic pressure of the wheel brake. Therefore, in Japanese Patent Application Laid-Open No. 64-70254, an electromagnetic switching valve having a normal hydraulic pressure passage and a throttle passage having an orifice is provided between the master cylinder and the brake hydraulic pressure control means. The operation of the flow control valve is controlled so that the means are connected via a normal hydraulic pressure path before the anti-lock brake control and via a throttle passage during the anti-lock brake control. In Japanese Utility Model Laid-Open Publication No. 2-26967, a throttle is formed in response to the output hydraulic pressure of the hydraulic pump acting during anti-lock brake control acting on the pilot hydraulic pressure chamber. A control valve which does not form a throttle is provided between the brake fluid pressure control means and the wheel brake.
[0003]
[Problems to be solved by the invention]
However, in the prior art disclosed in Japanese Patent Application Laid-Open No. 64-70254 and Japanese Utility Model Application Laid-Open No. 2-26967, it is possible to immediately apply the output hydraulic pressure of the master cylinder to the wheel brakes at the beginning of the brake operation. Japanese Unexamined Patent Publication (Kokai) No. 64-70254 requires an electromagnetic switching valve, which causes an increase in cost, and Japanese Unexamined Utility Model Publication (Kokai) No. 2-26967 complicates the hydraulic circuit due to the pilot hydraulic passage.
[0004]
The present invention has been made in view of such circumstances, and has a simple configuration, and enables a vehicle to quickly increase the brake fluid pressure of a wheel brake at an early stage of a brake operation despite the presence of an orifice. An object is to provide an anti-lock brake control device.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 can control the state of communication of the wheel brake between the master cylinder and the wheel brake between the master cylinder and the wheel brake. In a vehicle anti-lock brake control device provided with brake fluid pressure control means having an orifice mounted thereon, a detour is provided between the master cylinder and the wheel brakes to bypass the brake fluid pressure control means having the orifice, An actuator is interposed in this detour, and the actuator has a piston slidably fitted in the housing with both ends facing a first pressure chamber that always communicates with the master cylinder and a second pressure chamber that always communicates with the wheel brake. Ri formed is engaged, the piston, the hydraulic pressure in the second pressure chamber is first pressure Than chamber hydraulic, characterized in that the check valve that allows the flow of hydraulic fluid from the second pressure chamber in response to higher than a predetermined value to the first pressure chamber is provided.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described based on an embodiment of the present invention shown in the accompanying drawings.
[0008]
In FIG. 1, a brake hydraulic pressure control means 4 is provided between a master cylinder 2 which outputs a hydraulic pressure in response to an operation of a brake operation lever 1 and a wheel brake 3, and the brake hydraulic pressure control means 4 By controlling the hydraulic pressure of the wheel brake 3, the wheel on which the wheel brake 3 is mounted is prevented from falling into a locked state during braking.
[0009]
The brake fluid pressure control means 4 includes an orifice 5 connected to the master cylinder 2, a normally-open solenoid valve 6 provided between the orifice 5 and the wheel brake 3, a reservoir 7, and between the wheel brake 3 and the reservoir 7. A normally closed solenoid valve 8 provided; a return pump 11 having a suction port connected to the reservoir 7 via a suction valve 9 and a discharge port connected between the master cylinder 2 and the orifice 5 via a discharge valve 10; And has a well-known reflux type.
[0010]
In the antilock brake control, the return pump 11 is operated, and the normally closed solenoid valve 8 is opened in the closed state of the normally opened solenoid valve 6, whereby the brake fluid pressure of the wheel brake 3 is reduced. When both the normally-open and normally-closed solenoid valves 6 and 8 are closed, the brake fluid pressure of the wheel brake 3 is maintained, and the normally-open solenoid valve 6 is closed when the normally-closed solenoid valve 8 is closed. When the valve is opened, the brake fluid pressure of the wheel brake 3 is increased.
[0011]
A bypass 12 is provided between the master cylinder 2 and the wheel brake 3 to bypass the brake fluid pressure control means 4, and an actuator 13 is provided in the bypass 12.
[0012]
The actuator 13 has both ends facing the first pressure chamber 15 and the second pressure chamber 16 and a piston 18 urged toward the first pressure chamber 15 by a return spring 17 is slidably fitted in a housing 19. It is made up of The first pressure chamber 15 is always in communication with the master cylinder 2, and the second pressure chamber 16 is always in communication with the wheel brake 3. The return spring 17 is accommodated in the second pressure chamber 16 so as to be contracted between the piston 18 and the housing 19. Further, on the inner surface of the housing 19, there is provided a regulating step 19a which abuts on the peripheral edge of the end face of the piston 18 facing the second pressure chamber 16, and regulates the moving end of the piston 18 toward the second pressure chamber 16.
[0013]
In addition, the piston 18 of the actuator 13 is actuated from the second pressure chamber 16 to the first pressure chamber 15 as the hydraulic pressure of the second pressure chamber 16 becomes higher than the hydraulic pressure of the first pressure chamber 15 by a predetermined value or more. A check valve 20 is provided to allow the liquid to flow. The check valve 20 includes a valve seat 22 provided on the piston 18 with a valve hole 21 communicating with the second pressure chamber 16 facing the center, a spherical valve body 23 that can be seated on the valve seat 22, And a spring 24 for urging the valve body 23 in a direction in which the valve body 23 is seated on the spring 22. The spring 24 is contracted between the retaining ring 25 fitted to the piston 18 and the valve body 23.
[0014]
Next, the operation of this embodiment will be described. Normally, the normally open solenoid valve 6 in the brake fluid pressure control means 4 is open and the normally closed solenoid valve 8 is closed in normal times. In this state, when the master cylinder 2 is operated by the brake operating lever 1, the output hydraulic pressure of the master cylinder 2 acts on the wheel brake 3 via the orifice 5 and the normally-open solenoid valve 6, Acting on the pressure chamber 15, the piston 18 of the actuator 13 operates in a direction to reduce the volume of the second pressure chamber 16, and the hydraulic pressure of the second pressure chamber 16, which has been increased due to the volume reduction, is applied to the wheel brake 3. Will work. That is, the brake fluid pressure is quickly applied to the wheel brake 3 from the actuator 13 having a small flow resistance without being affected by an increase in the flow resistance due to the flow of the orifice 5 and the normally-open solenoid valve 6, and the wheels are quickly moved. Can be braked.
[0015]
After the output hydraulic pressure of the master cylinder 2 reaches a predetermined value and the piston 18 of the actuator 13 comes into contact with the regulating step 19a, the output hydraulic pressure of the master cylinder 2 is changed to the orifice 5 and the normally open solenoid valve. Only through the wheel 6 acts on the wheel brake 3, and a rapid pressure increase is suppressed. When the hydraulic pressure in the second pressure chamber 16 becomes equal to the hydraulic pressure in the first pressure chamber 15 in the actuator 13, the piston 18 is returned to the position shown in FIG.
[0016]
During anti-lock brake control accompanying the tendency of the wheels to lock during such a brake operation, the operation of the return pump 11 is started, and when the brake fluid pressure is reduced, the normally-open solenoid valve 6 is closed. And the normally closed solenoid valve 8 is opened. As a result, the brake fluid pressure of the wheel brake 3 is absorbed by the reservoir 7 or returned to the master cylinder 2 side, and the brake fluid pressure of the wheel brake 3 is reduced.
[0017]
At this time, in the actuator 13, the hydraulic pressure in the second pressure chamber 16 decreases, and accordingly, the piston 18 moves to a moving end toward the second pressure chamber 16, that is, a position where it comes into contact with the regulating step 19 a.
[0018]
When the tendency to lock the wheels is eliminated due to a decrease in the braking force due to a decrease in the brake fluid pressure of the wheel brake 3, the normally-open solenoid valve 6 is opened and the normally-closed solenoid valve is opened to restore the braking force. 8 is closed. Therefore, the output hydraulic pressure of the master cylinder 2 acts on the wheel brake 3 again through the orifice 5 and the normally-open solenoid valve 6, and a rapid increase in the pressure of the wheel brake 3 is avoided by the throttle action of the orifice 5. Accurate braking force recovery becomes possible. At this time, in the actuator 13, the piston 18 is at the moving end toward the second pressure chamber 16.
[0019]
By repeating the opening / closing control of the normally-open solenoid valve 6 and the normally-closed solenoid valve 8 at high speed, the brake pressure of the wheel brake 3 is efficiently controlled.
[0020]
When the brake operation lever 1 is returned to put the master cylinder 2 in an inoperative state, a check is made as the hydraulic pressure of the second pressure chamber 16 in the actuator 13 becomes higher than the hydraulic pressure of the first pressure chamber 15 by a predetermined value or more. The valve 20 is opened, and the hydraulic pressure of the wheel brake 3 is released to the master cylinder 2 mainly through the bypass 12. Therefore, also in this case, the wheel brake 3 is quickly returned to the inoperative state without being affected by the throttle resistance in the normally-open solenoid valve 6 and the orifice 5.
[0021]
In this manner, the piston 18 having both ends facing the first pressure chamber 15 that always communicates with the master cylinder 2 and the second pressure chamber 16 that always communicates with the wheel brake 3 is slidably fitted to the housing 19. With the simple structure in which the actuator 13 is provided in the detour 12 bypassing the brake fluid pressure control means 4, the output fluid pressure of the master cylinder 2 is immediately applied to the wheel brake 3 at the initial stage of the brake operation, and the anti-lock brake is provided. Slow pressure increase at the time of control can be made possible, and the configuration can be simplified and the cost can be reduced as compared with the conventional one which requires an electromagnetic valve and a pilot hydraulic pressure path.
[0022]
Further, the check valve 20 for enabling the wheel brake 3 to quickly return to the inoperative state at the end of the brake operation is provided on the piston 18 of the actuator 13, thereby simplifying the configuration of the check valve 20 itself. As a result, cost can be reduced, and an extra space for installing the check valve 20 can be eliminated.
[0023]
As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is possible.
[0024]
For example, instead of the normally-open solenoid valve 6 and the normally-closed solenoid valve 8 in the brake fluid pressure control means 4, a state in which the wheel brake 3 and the master cylinder 2 are connected but the wheel brake 3 and the reservoir 7 are shut off. To switch between a state in which the wheel brake 3 and the master cylinder 2 are cut off but the wheel brake 3 and the reservoir 7 are connected, and a state in which the wheel brake 3 and the master cylinder 2 and both the wheel brake 3 and the reservoir 7 are cut off. An enabled electromagnetic switching valve may be used.
[0025]
【The invention's effect】
As described above, according to the first aspect of the present invention, a bypass is provided between the master cylinder and the wheel brake to bypass the brake fluid pressure control means having an orifice, and an actuator is provided in the bypass, and the actuator is provided. but a first pressure chamber communicating constantly with the master cylinder, the second pressure chamber and the piston to face the opposite ends leading always to the wheel brakes Ru formed is slidably fitted in the housing, the solenoid valve and the pilot fluid With a simple and low-cost configuration that eliminates the need for a pressure path, the output hydraulic pressure of the master cylinder 2 can be immediately applied to the wheel brakes at the beginning of the brake operation, and a gradual increase in pressure during antilock brake control is possible. It can be.
[0026]
In particular, the piston allows the flow of the hydraulic fluid from the second pressure chamber to the first pressure chamber as the hydraulic pressure of the second pressure chamber becomes higher than the hydraulic pressure of the first pressure chamber by a predetermined value or more. A check valve is provided to reduce the cost by simplifying the structure of the check valve itself, which enables quick return to the inoperative state of the wheel brake at the end of the brake operation, and to install the check valve. Extra space can be eliminated.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram of an antilock brake control device for a vehicle.
[Explanation of symbols]
2 ... master cylinder 3 ... wheel brake 4 ... brake fluid pressure control means 5 ... orifice 13 ... actuator 15 ... first pressure chamber 16 ... second pressure chamber 18 ...・ Piston 19 ・ ・ ・ Housing 20 ・ ・ ・ Check valve

Claims (1)

Between the master cylinder (2) and the wheel brake (3), the communication state of the wheel brake (3) with the master cylinder (2) and the reservoir (7) can be controlled, and the master cylinder (2) and the wheel brake ( 3) An anti-lock brake control device for a vehicle in which brake fluid pressure control means (4) having an orifice (5) interposed therebetween is provided.
A bypass (12) is provided between the master cylinder (2) and the wheel brake (3) to bypass the brake fluid pressure control means (4) having the orifice (5), and an actuator is provided in the bypass (12). (13) is interposed,
The actuator (13) has a piston (18) having both ends facing a first pressure chamber (15) always communicating with the master cylinder (2) and a second pressure chamber (16) always communicating with the wheel brake (3). There Ri formed is slidably fitted in the housing (19),
The piston (18) is provided with the first pressure chamber (16) from the second pressure chamber (16) in response to the hydraulic pressure of the second pressure chamber (16) being higher than the hydraulic pressure of the first pressure chamber (15) by a predetermined value or more. An anti-lock brake control device for a vehicle, comprising: a check valve (20) for allowing a flow of a hydraulic fluid to a pressure chamber (15) .

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