JPH05124496A - Control device for brake fluid pressure - Google Patents

Abstract

PURPOSE:To eliminate kick back of a brake pedal by supplying brake fluid from a pump communicating port to a wheel brake communicating port or a reservoir communicating port, in the condition of blockading a master cylinder communicating port with the spool of a flow valve. CONSTITUTION:At repressurized condition, a spool 14 is moved between the opened condition and the closed condition of a second hole 30 according to the pressure difference between the upper and lower parts of the spool. At the same time, brake fluid in a reservoir 9 is supplied to a wheel brake 4 by means of a pump 10 through a pump communicating port 12, the second hole 30, an upper hole 23, a small bore hole 25, a lower hole 24, a fourth hole 32, and a second port 7b of wheel brake communicating ports 7. In the condition in which the brake fluid in the reservoir 9 is discharged to the pump communicating port 12 side, communication between a master cylinder communicating port 6 and the upper hole the pump communicating port 12 and the second hole 30 is let flow to the wheel brake side by nearly constant quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control device for anti-skid control used in a brake device of a vehicle or the like.

[0002]

2. Description of the Related Art Among brake fluid pressure control devices for anti-skid control adopted in a vehicle brake device for the purpose of preventing a tire from falling into a locked state during braking, as shown in FIG. Master cylinder 51
Master cylinder communication port 52 that communicates with the wheel brake communication port 54 that communicates with the wheel brake 53
And the reservoir 56 and the reservoir 5 via the normally closed valve 55.
A flow valve 61 including a casing 59 having a reservoir communication port 58 that communicates with the suction side of a pump 57 that sucks and discharges the brake fluid in 6 and a spool 60 that is movably provided in the casing 59 is adopted. (Japanese Patent Laid-Open No. 1-297350).

This flow valve 61 has its spool 6
0 causes the master cylinder communication port 52 and the wheel brake communication port 54 to communicate with each other when the anti-skid control is not operated, and the master cylinder communication port 52 is opened by the differential pressure due to the normally closed valve 55 being opened when the anti-skid control is depressurized. The brake fluid which is closed and makes the wheel brake communication port 54 communicate with the reservoir communication port 58, and the normally closed valve 55 is closed at the time of repressurization to return the brake fluid to the pump 57 via the pump communication port 62. It is supplied to the brake 53.

Here, the brake fluid pressure control device 50
In addition to supplying the brake fluid to the wheel brake 53 side at the time of the above-mentioned re-pressurization, a substantially constant amount of brake fluid is supplied from the pump 57 side to the master cylinder 51 side via the orifice 64 provided in the path 63. It is configured to return with.

[0005]

However, in the brake fluid pressure control device 50 having the above structure, the pump 57 is used.
The flow rate of the brake fluid returning to the master cylinder 51 side via the orifice 64 fluctuates to some extent due to the fluctuation of the discharge pressure in the master cylinder 51, which causes a stroke fluctuation (a so-called kickback to the brake pedal) in the master cylinder 51. , And needed further improvement in this respect.

Therefore, an object of the present invention is to provide a brake fluid pressure control device that reliably suppresses stroke fluctuation of the master cylinder and does not kick back to the brake pedal.

[0007]

In order to achieve the above object, a brake fluid pressure control device of the present invention comprises a master cylinder communication port communicating with a master cylinder, a wheel brake communication port communicating with a wheel brake, and a normally closed valve. Via a reservoir and a reservoir communication port communicating with the suction side of a pump for sucking and discharging the brake fluid in the reservoir, and a casing movably provided in the casing and urged in one direction by a spring. A flow valve having a spool, the spool of the flow valve being in a stationary state biased in one direction by the spring, the master cylinder communication port and the wheel brake communication via the passage of the spool. Brake fluid flows out to the reservoir by opening the normally closed valve and communicating with the port. By closing the master cylinder communication port with a differential pressure generated on both sides of the spool and connecting the wheel brake communication port and the reservoir communication port, the casing of the flow valve is configured to discharge the pump. Has a pump communication port communicating with the side, the spool of the flow valve, in a state of closing the master cylinder communication port,
The passage and the pump communication port are arranged so that brake fluid can be supplied from the pump communication port to the wheel brake communication port or the reservoir communication port via the passage of the spool.

[0008]

According to the brake fluid pressure control apparatus of the present invention, when the pump is discharging the brake fluid in the reservoir (during re-pressurization), the spool of the flow valve almost completely closes the master cylinder communication port. Since it is closed and the pump communication port and the wheel brake communication port are communicated with each other, the brake fluid discharged from the pump is not returned to the master cylinder side.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brake fluid pressure control device according to an embodiment of the present invention will be described below with reference to FIGS. The upper and lower sides used in the following description are those used in the drawings for convenience.

In the figure, reference numeral 1 is a brake hydraulic pressure control device for anti-skid control, reference numeral 2 is a master cylinder which is connected to a brake pedal 3 and generates a hydraulic pressure in response to an input of the brake pedal 3, and reference numeral 4 is a brake fluid. The wheel brakes that brake the wheels by pressure are shown respectively.

The brake fluid pressure control device 1 is provided with a flow valve 5 which is a flow rate control switching valve. The flow valve 5 has a master cylinder communication port 6 communicating with the master cylinder 2 and a wheel brake 4. To the wheel brake communication port 7, a reservoir 9 via a solenoid normally closed valve 8 and a reservoir communication port 11 communicating with the suction side of a pump 10 for sucking and discharging the brake fluid in the reservoir 9, and the discharge of the pump 10. A substantially cylindrical casing 13 having a pump communication port 12 communicating with the side is provided. Inside the casing 13, a substantially cylindrical spool 14 is slidable along the inner peripheral surface of the casing 13. It has been inserted.

Here, the master cylinder communication port 6 is provided below the upper inner end surface 15 of the casing 13 by a predetermined amount in a direction orthogonal to the axis of the casing 13. Also,
The wheel brake communication port 7 is provided below the master cylinder communication port 6 by a predetermined amount in parallel with the first port 7a, and below the first port 7a by a predetermined amount in parallel with the second port. It has a port 7b, and the first port 7a and the second port 7b communicate with each other through an external path 7c. Further, the reservoir communication port 11 is provided at the lower inner end of the casing 13 along the axis of the casing 13, and the pump communication port 12 connects the master cylinder communication port 6 and the first port 7a of the wheel brake communication port 7. It is provided at a predetermined position between and in parallel with these.

The reservoir 9 has a piston 17 slidably accommodated in a cylinder 16 so as to have a variable capacity for accumulating brake fluid, and a spring 18 for urging the piston 17 with a predetermined urging force. On the other hand, the suction valve 1 is installed in the pump 10 so that the brake fluid is sucked only from the reservoir 9 side and is discharged only toward the pump communication port 12.
9 and the discharge valve 20 are provided on both sides. Further, a bypass path 21 bypassed is provided on both sides of the suction valve 19 and the discharge valve 20 of the pump 10, and this bypass path 21 is provided when the pressure on the discharge side of the pump 10 becomes higher than a predetermined value. A relief valve 22 that releases the residual pressure to the suction side of the pump 10 is provided. The relief pressure of the relief valve 22 is preferably set to be slightly higher than the pressure on the master cylinder 2 side.
The discharge pressure can be adjusted to a pressure commensurate with the pressure on the master cylinder 2 side.

Then, the spool 14 of the flow valve 5
Is an upper hole 23 formed in the center of the upper portion of the spool 14 along the axis of the spool 14 and opening upward.
The spool 14 has a lower hole 24 formed in the center of the lower portion thereof along the axis of the spool 14 and opening toward the reservoir communication port 11 side. The upper hole 23 and the lower hole 24 are located more than these. The small-diameter holes 25 each having a fixed small-diameter are communicated with each other. Here, at the lower end of the lower hole 24, a spring 27 for biasing the spool 14 upward by a predetermined biasing force is inserted so that the upper end surface 26 of the spool 14 is brought into contact with the upper inner end surface 15 of the casing 13. Is provided with a step portion 28.

The spool 14 has a casing 13
In order to switch each port of the
9, second hole 30, third hole 31, and fourth hole 32 are provided in a direction orthogonal to the axis of the spool 14. These will be described below.

The first hole 29 controls communication between the master cylinder communication port 6 and the upper hole 23, and the spool 1
4 is urged by the spring 27 and the upper end surface 26 of the casing 13 is brought into contact with the upper inner end surface 15 of the casing 13 (shown in a stationary state in FIG. 1) so that the upper hole 23 and the master cylinder communication port 6 communicate with each other. From this stationary state, when the electromagnetic normally-closed valve 8 is opened and the brake fluid flows out to the reservoir 9 side in accordance with the operation of the anti-skid control, the spool 14 is spring-loaded by the differential pressure generated on both sides of the small diameter hole 25 of the spool 14. In the state of moving downward against the urging force of 27 (shown in FIG. 2: reduced pressure state), the communication between the master cylinder communication port 6 and the upper hole 23 is blocked (that is, the master cylinder communication port 6 is closed), and From this depressurized state, the electromagnetic normally closed valve 8 is closed and the brake fluid in the reservoir 9 is being discharged by the pump 10 (shown in FIG. 3: repressurized state). In are intended to be positioned to keep blocking the communication between the master cylinder communication port 6 and the upper hole 23.

The second hole 30 communicates the pump communication port 12 with the upper hole 23 in the stationary state, and in the depressurized state and the repressurized state, the pump communication port 12 responds to the movement due to the differential pressure on both sides of the spool 14. The upper hole 23 and the upper hole 23 are arranged so as to appropriately control the connection / disconnection.

The third hole 31 controls the communication between the first port 7a of the wheel brake communication port 7 and the upper hole 23. In the stationary state, the first port 7a communicates with the upper hole 23, and It is arranged so as to block the communication between the first port 7a and the upper hole 23 in the depressurized state and the repressurized state.

The fourth hole 32 controls the communication between the second port 7b of the wheel brake communication port 7 and the lower hole 24, and blocks the communication between the second port 7b and the lower hole 24 in the stationary state. In the depressurized state and the repressurized state, the second port 7b and the lower hole 24 are arranged to communicate with each other. The above-mentioned upper hole 23,
The lower hole 24, the small diameter hole 25, the first hole 29, the second hole 30, the third hole 31, and the fourth hole 32 form a passage of the spool 14.

In the brake fluid pressure control device 1 having the above-described structure, the spool 14 of the flow valve 5 is in a stationary state in which the upper end surface 26 is brought into contact with the upper inner end surface 15 of the casing 13 as shown in FIG. The master cylinder 2 and the wheel brake 4 are communicated with each other through the master cylinder communication port 6, the first hole 29, the upper hole 23, the third hole 31, and the first port 7a of the wheel brake communication port 7 for normal operation, that is, the wheel. Brake 4 to brake pedal 3
It is designed to pressurize in accordance with the stepping on the button (anti-skid control inactive). At this time, the upper hole 23 and the pump communication port 12 are connected to the second hole 30.
However, the pump 10 is provided with the discharge valve 20 which is a check valve, and the relief valve 22 is not opened by the brake fluid pressure from the master cylinder 2 by the operation of the brake pedal 3. Since the valve opening pressure is set as described above, the brake fluid does not flow from the pump communication port 12 to the reservoir 9 side. Further, at this time, since the fourth hole 32 is located at a position that blocks communication between the second port 7b of the wheel brake communication port 7 and the lower hole 24, the brake fluid does not flow there.

Further, when the anti-skid control is in a depressurized state, that is, when the wheels tend to lock, it is judged from information from a sensor (not shown) or the like, and the electromagnetic normally closed valve 8 is opened to avoid this locking tendency. Then, the brake fluid existing in the portion constituted by the lower hole 24 and the lower portion of the casing 13 flows into the reservoir 9, and thereby both sides of the spool 14 of the flow valve 5 (the upper hole 23 side and the lower hole 24 side). ), The spool 14
Moves downward against the biasing force of the spring 27. Then, the spool 14 blocks the communication between the master cylinder communication port 6 and the wheel brake communication port 7,
In addition, the wheel brake 4 and the reservoir 9 are communicated with each other through the second port 7b of the wheel brake communication port 7, the fourth hole 32 and the lower hole 24, and the brake fluid in the wheel brake 4 is caused to flow into the reservoir 9 to cause the wheel brake. The brake fluid pressure of No. 4 is reduced (the flow of the brake fluid at this time is shown by an arrow in FIG. 2). At this time, the upper hole 23 and the pump communication port 12 are connected to the second hole 30.
However, the brake fluid does not flow from the pump communication port 12 to the reservoir 9 side as described above. Further, at this time, the third hole 31 is located at a position that blocks the communication between the first port 7a of the wheel brake communication port 7 and the upper hole 23, and the brake fluid does not flow there.

Further, if a predetermined amount of wheel locking tendency is avoided from the above state, the anti-skid control is re-pressurized. In this re-pressurized state, as shown in FIG. The valve 8 is closed and the pump 10
3 is operated or started, the spool 14 which is slightly lower than the state shown in FIG. 3 has the state shown in FIG. 3 and the second hole 30 depending on the differential pressure between the upper side and the lower side of the spool 14. It moves between the open state and the closed state of the second hole 30. At this time, of course, the outflow of the brake fluid to the reservoir 9 is stopped, and together with this, the pump 1
0 causes the brake fluid in the reservoir 9 to the wheel brake 4, the pump communication port 12, the second hole 30, the upper hole 23,
It is supplied through the small diameter hole 25, the lower hole 24, the fourth hole 32 and the second port 7b (the flow of the brake fluid at this time is shown by an arrow in FIG. 3). Here, in the state where the brake fluid in the reservoir 9 is discharged from the pump 10 to the pump communication port 12 side as described above, the spool 14 is always in the master cylinder communication port 6 and the upper hole 23.
To disconnect the communication with the pump communication port 12 and the second hole 3
The amount of communication with 0 is balanced so that a substantially constant amount of brake fluid is always flowed to the wheel brake 4 side, and when the brake fluid discharged from the pump 10 is exhausted, the biasing force of the spring 27 is resisted. Then spool 14
The pressure that balances the downward pressure disappears on the side of the upper hole 23, and the stationary state described above is restored. In the repressurized state, the third hole 31 is located at a position where it blocks the communication between the first port 7a of the wheel brake communication port 7 and the upper hole 23, and the brake fluid does not flow there.

Further, in the present embodiment, the relief valve 22 uses the residual pressure of the pump 10 when the pressure between the pump 10 and the flow valve 5 becomes higher than a predetermined pressure.
Since it is released to the suction side, the load pressure above a certain value does not act on the pump 10, and the hydraulic pressure rise can be prevented.

[0024]

As described above in detail, according to the brake fluid pressure control device of the present invention, when the pump is discharging the brake fluid in the reservoir (during re-pressurization), the spool of the flow valve is Blocks the master cylinder communication port and connects the pump communication port and the wheel brake communication port, so that the brake fluid discharged from the pump is not returned to the master cylinder side. Therefore, the stroke variation of the master cylinder can be surely suppressed, and uncomfortable kickback to the brake pedal can be eliminated.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a brake fluid pressure control device according to an embodiment of the present invention, showing a non-operating state of an anti-skid control.

FIG. 2 is a schematic diagram showing a brake fluid pressure control device according to an embodiment of the present invention, showing a depressurized state of an anti-skid control.

FIG. 3 is a schematic diagram showing a brake fluid pressure control device according to an embodiment of the present invention, showing a re-pressurized state of an anti-skid control.

FIG. 4 is a cross-sectional view showing a conventional brake fluid pressure control device.

[Explanation of symbols]

 1 Brake Fluid Pressure Control Device 2 Master Cylinder 4 Wheel Brake 5 Flow Valve 6 Master Cylinder Communication Port 7 Wheel Brake Communication Port 8 Electromagnetic Normally Closed Valve (Normally Closed Valve) 9 Reservoir 10 Pump 11 Reservoir Communication Port 12 Pump Communication Port 13 Casing 14 Spool 23 Upper hole (passage) 24 Lower hole (passage) 25 Small diameter hole (passage) 29 First hole (passage) 30 Second hole (passage) 31 Third hole (passage) 32 Fourth hole (passage) 27 Spring

Claims (1)

[Claims] 1. A master cylinder communication port that communicates with a master cylinder, a wheel brake communication port that communicates with a wheel brake, and a normally closed valve that communicate with a reservoir and a suction side of a pump that sucks and discharges brake fluid from the reservoir. A casing having a reservoir communication port,
A flow valve having a spool movably provided in the casing and biased in one direction by a spring, wherein the spool of the flow valve is in a stationary state biased in one direction by the spring. Then, the master cylinder communication port and the wheel brake communication port are communicated with each other through the passage of the spool, the normally closed valve is opened, and the brake fluid flows toward the reservoir, so that the fluid is generated on both sides of the spool. In the brake fluid pressure control device that closes the master cylinder communication port with a differential pressure that causes the wheel brake communication port and the reservoir communication port to communicate with each other, the casing of the flow valve has a pump communication port that communicates with a discharge side of the pump. The spool of the flow valve communicates with the master cylinder. The passage and the pump communication port are arranged so that the brake fluid can be supplied from the pump communication port to the wheel brake communication port or the reservoir communication port through the passage of the spool when the valve is closed. A brake fluid pressure control device characterized by the above.