JPH1178849A - Brake fluid pressure controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wheel cylinder pressure corresponding to a master cylinder by detecting a master cylinder pressure and a wheel cylinder pressure respectively by first and second pressure sensors and performing control so as to set the detection outputs thereof to a specified relationship. SOLUTION: When detecting a failure in a brake booster system by a sensor 15 for detecting the failure of a brake booster, an L terminal 16 for detecting an engine stop and a signal from a brake switch 17, an electronic controller(ECU) drives a motor M to actuate a pump 5 for a failure. Then, a shut valve 6 as a control valve device and a cut valve 7 are opened/ closed so as to set a relationship between a master cylinder pressure signal P/S1 and a wheel cylinder pressure signal P/S2 to a predetermined specified ratio, and wheel cylinder fluid pressure supplied from the failure pump 5 is controlled to match the pressing force of a brake pedal.

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 having a boosting function such as a vacuum brake booster or a hydraulic brake booster. It relates to a brake fluid pressure control device that can perform a brake operation when the brake pedal is depressed as a brake operating member in a state where the force function does not operate normally and in the same manner as when the boost function is operating. is there.

[0002]

2. Description of the Related Art In general, an unfamiliar driver or a driver who has become accustomed and has fallen into a panic state cannot step on the brakes strongly and cannot maintain the pedaling force for a long time. For this reason, the development of brake fluid pressure control devices that maximize the performance of brakes, including anti-lock control systems, has recently been promoted, and as one of such development directions, various developments related to improving the performance of brake boosters have been carried out. Is underway.

[0003]

SUMMARY OF THE INVENTION For example, Japanese Patent Application Laid-Open No. H8-8
The brake booster (hydraulic booster) described in No. 7430 has a movable valve body slidably disposed in a piston that slides in a cylinder hole in the hydraulic booster, and the movable valve is provided with a movable valve body. By supporting the left and right ends of the body with seal rings,
Vibration of the movable valve body due to a rapid flow of hydraulic pressure during operation of the device is suppressed, and generation of abnormal noise is prevented.

In the above-described hydraulic booster, for example, when an engine trouble occurs during running and the engine stops, or when the accumulator for the booster fails, the brake operation is performed. When the member is operated, the boosting function does not operate normally.
In order to prepare for such a situation, the conventional brake device transmits the hydraulic pressure generated in the master cylinder to the wheel cylinder as it is, even if the above-mentioned situation occurs, so that the brake can be operated safely. It has a structure. However, in such a state, there is a problem that the pedal effort of the brake pedal fluctuates greatly from the normal state.

Accordingly, the present invention newly provides a fail pump system which operates when a brake operating member is operated in a state where an engine trouble or a failure has occurred in an accumulator or the like in a conventional brake device. It is another object of the present invention to provide a brake fluid pressure control device capable of securing a braking force as normal, and to solve the above-mentioned problems.

The present invention provides a failure pump which operates by detecting the occurrence of the above-described failure in a brake hydraulic circuit including a conventional anti-lock control modulator, and an electronic pump when the pump is operated. An extremely safe brake fluid pressure control device can be obtained simply by retrofitting a shut valve and a cut valve that opens and closes according to commands from the control device, and there is no significant change in the brake circuit. But it is advantageous.

[0007]

SUMMARY OF THE INVENTION Accordingly, the technical solution adopted by the present invention comprises a brake booster, and a brake hydraulic pressure which is increased by a second booster when the function of the brake booster is abnormal. A control device, wherein a hydraulic pressure control device for anti-lock control is provided between the second booster and a wheel cylinder, wherein the second booster includes a hydraulic pressure source device for pressurizing the wheel cylinder, and a master device. It has a first and a second pressure sensor for detecting a cylinder pressure and a wheel cylinder pressure, respectively, and a control valve device for controlling outputs of the first and the second pressure sensors so as to have a predetermined relationship. This is a brake fluid pressure control device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a brake fluid pressure control device according to the embodiment, and FIG. 2 is a diagram for controlling a valve in the device. 3 is a configuration diagram of a control circuit of FIG. In FIG. 1, 1
Is a brake pedal as a brake operating member, 2 is a brake booster (first booster), 3 is a master cylinder, 4 is a wheel cylinder, and a master cylinder 3
A motor M, a pump for failure (hydraulic pressure source device) 5, a shut valve 6, a cut valve 7, and first to third check valves 8, 9, 10 As shown, a second booster A is disposed, and a hold valve, a decay valve, an antilock control reservoir, a hydraulic pump, a motor are provided between the second booster A and the wheel cylinder 4. (For example, Japanese Patent No. 2563860) known anti-lock modulator (fluid pressure control device for anti-lock control)
B is arranged. The above-described first booster (brake booster) 2, master cylinder 3, and wheel cylinder 4 also have the same configurations as those conventionally known, and FIG. Although it is a piping configuration consisting of a configuration, it can be applied to a so-called two-system or three-system piping configuration, and the second booster can be common to each wheel.

An electronic control unit (ECU) for controlling the second booster A provided in the pipe path is common to the ABS unit B, and the electronic control unit (ECU) includes, as shown in FIG. In addition to signals from various sensors used for conventional antilock control, a signal from a sensor 15 (detecting an accumulator pressure) for detecting a brake booster failure, and an L terminal 16 (detecting an engine stop) Signal), a signal from the brake switch (SW) 17, a master cylinder pressure signal P / S1 from a pressure sensor (first pressure sensor) for detecting a master cylinder pressure, and a pressure sensor for detecting a wheel cylinder pressure. The wheel cylinder pressure signal P / S2 from the (second pressure sensor) is input. When a failure of the brake booster system is detected based on signals from the sensors 15, 16, 17 and the like, the electronic control unit drives the motor M to operate the fail pump 5, and simultaneously outputs the master cylinder pressure signal P / The shut valve 6 and the cut valve 7 as a control valve device are opened and closed so that S1 and the wheel cylinder pressure signal P / S2 have a predetermined ratio, and the wheel cylinder 4 supplied from the failure pump 5 The hydraulic pressure is adjusted to the hydraulic pressure according to the depression force of the brake pedal.

The second booster A disposed in the piping path will be described in more detail with reference to FIG. 1. In the piping connecting the master cylinder 3 and the ABS device B, a shut valve 6 is provided. Two pipes 11 and 12 are provided in parallel with the shut valve 6, and a first check valve 8, a second check valve 9 and a cut valve 7 are interposed in one pipe 12 in series. The third check valve 10 is interposed in the other pipe 12. The shut valve 6 is configured as a normally-open two-position switching valve, the first check valve 8 is a check valve that allows the flow of fluid from the master cylinder 3 side to the wheel cylinder 4 side, and the second check valve 9 is a wheel check valve. The cut valve 7 is configured as a normally closed two-position switching valve, and is configured as a check valve that allows the flow of fluid from the cylinder 4 side to the master cylinder 3 side. The third check valve 10 is configured as a check valve that allows a fluid flow from the master cylinder 3 side to the wheel cylinder 4 side.

A pipe 13 communicates between the first check valve 8 and the second check valve 9 and downstream of the shut-off valve. In the pipe 13, fluid is supplied from the pipe 11 to the wheel cylinder 4. A fail pump 5 that can be pumped is provided. The fail pump 5 is operated by a motor M. The fluid pressure upstream of the shut valve 6 is detected by a master cylinder pressure signal P / S1, and the fluid pressure downstream of the shut valve 6 is detected by a pressure sensor as a wheel cylinder pressure signal P / S2. I have.

The operation of the brake fluid pressure control device having the above configuration will be described. Normal operation In FIG. 1, when a brake pedal 1 as a brake operating member is operated, a brake booster (first booster)
The hydraulic pressure is generated in the master cylinder 3 by the force assisted by the second booster 2, and this hydraulic pressure passes through the open shut valve 6 of the second booster A through the hold valve in each ABS device B, and the wheel cylinder 4 and the brake is activated. When the brake pedal 1 is released, the hydraulic pressure in the wheel cylinder 4 returns to the master cylinder 3 through the reverse route, and the brake is released. If the wheels tend to lock while the brakes are operating, the ABS device B performs the same anti-lock control as before by the command from the electronic control unit (ECU), and holds, reduces, and re-presses the brake fluid pressure. I do. The antilock control mode can adopt the conventional mode as it is, and the control mode is the same, so that the detailed description is omitted.

At the time of a failure An engine trouble or a failure occurs in the brake booster 2 or the like, and the state is input to the electronic control unit (ECU) as an L terminal 16 signal and a brake booster failure signal 15, and in this state, the brakes When the brake switch (SW) is turned ON by stepping on the motor, the motor M of the failure pump 5 is turned on.
Is driven, and at the same time, the shut valve 6 is closed. When the failure pump 5 is operated, the master cylinder 3
The hydraulic pressure from the pump is pumped up through the first check valve 8 to increase the pressure, and is supplied to the wheel cylinder 4 via the ABS device B to operate the brake. At this time, the master cylinder pressure signal P / S1 and the wheel cylinder pressure signal P / S2 are sent to the electronic control unit, where the master cylinder pressure signal P / S1 and the wheel cylinder pressure signal P / S2 are predetermined. The shut valve 6 and the cut valve 7 are opened and closed so as to reach a predetermined ratio (pressure increase ratio).

That is, at the time of pressurization, both the shut valve 6 and the cut valve 7 close the flow path as shown in FIG. 3, and at the same time, are pumped up from the master cylinder 3 via the first check valve 8 by the fail pump 5 and discharged. The brake fluid pressure is increased by supplying the fluid to the wheel cylinder 4 as it is. At the time of holding, as shown in FIG. 4, when the shut valve 6 is closed and the cut valve 7 is opened, the brake fluid pumped up by the fail pump 5 circulates through the cut valve 7 and the brake fluid pressure is held. When the pressure is reduced, the shut valve 6 is opened as shown in FIG. 5, and when the cut valve 7 is opened, the brake fluid pumped up from the wheel cylinder 4 by the fail pump 5 is returned to the master cylinder 3 via the shut valve 6. The brake fluid pressure is reduced.

The above-described pressurizing, holding and depressurizing operations are performed by commands from the electronic control unit so that the master cylinder pressure signal P / S1 and the wheel cylinder pressure signal P / S2 have a predetermined ratio. The control is executed by opening and closing the shut valve 6 and the cut valve 7 so that the brake fluid pressure becomes a desired value. Further, when the brake pedal 1 is released, the failure pump 5 stops and the shut valve 6,
Since the cut valve 7 also returns to the initial state, the brake fluid in the wheel cylinder returns to the master cylinder 3 via the open shut valve 6, and the brake is released.
In addition, if the wheels tend to lock during the normal operation or during the braking operation at the time of the failure, the ABS device is operated by a command from the electronic control unit to control the brake fluid pressure in the same manner as in the conventional device, thereby locking the wheels. The tendency can be avoided.
As described above, according to the present invention, when the brake booster fails or the brake pedal is operated with the engine stopped, the operation of the second booster causes the pedal feeling to be less than before the failure. The safety can be increased because the brake can be applied without changing.

[0016]

As described in detail above, according to the present invention,
When the brake booster fails or the brake pedal is operated with the engine stopped, the fail pump in the second booster is activated, and the master cylinder pressure signal P / S1 and the wheel cylinder pressure are output. Signal P / S2
The shut-off valve and the cut valve are opened and closed so that a predetermined value is obtained, and a wheel cylinder pressure corresponding to the master cylinder can be obtained, and a highly safe brake fluid pressure control device can be obtained. . Further, since the configuration is such that it can be retrofitted to the conventional brake fluid pressure control device, it is possible to cope with various types of vehicles and to achieve excellent effects such as being able to configure the entire system at low cost. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a brake fluid pressure control device according to the present embodiment.

FIG. 2 is a configuration diagram of an electronic control circuit according to the embodiment.

FIG. 3 is a configuration diagram in which the brake fluid pressure control device is in a pressurized state.

FIG. 4 is a configuration diagram in which the brake fluid pressure control device is in a holding state.

FIG. 5 is a configuration diagram in which the brake fluid pressure control device is in a reduced pressure state.

[Explanation of symbols]

 Reference Signs List 1 brake pedal 2 first booster (brake booster) 3 master cylinder 4 wheel cylinder 5 fail pump (hydraulic pressure source device) 6 shut valve (control valve device) 7 cut valve (control valve device) 8 first check valve 9 Second check valve 10 Third check valve A Second booster B ABS device

Claims (3)

[Claims] 1. A brake fluid pressure control device comprising a brake booster, wherein a brake fluid pressure is increased by a second booster when a function of the brake booster is abnormal. A hydraulic pressure control device for anti-lock control is provided therebetween, and the second booster includes:
A hydraulic pressure source device for pressurizing a wheel cylinder, and a first device for detecting a master cylinder pressure and a wheel cylinder pressure, respectively.
A brake fluid pressure control device comprising: a second pressure sensor; and a control valve device for controlling outputs of the first and second pressure sensors to have a predetermined relationship. 2. The brake fluid pressure control device according to claim 1, wherein the fluid pressure source device has a pump that sucks brake fluid from a master cylinder and discharges the brake fluid to a wheel cylinder. 3. A normally open shut valve provided in a passage connecting a master cylinder and a discharge port of a pump, and a normally closed shut valve provided in a passage connecting a wheel cylinder and a suction port of the pump. The brake fluid pressure control device according to claim 2, further comprising a mold-type cut valve.