JPH1178850A - Brake fluid pressure controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wheel cylinder pressure corresponding to a master cylinder by detecting the generation of a failure to actuate an antilock control pump, and simultaneously adjusting a fluid pressure in the wheel cylinder and a master cylinder fluid pressure by a balance valve in a circuit. SOLUTION: An accumulator pressure state in a brake booster 2 as a booster is inputted as a brake booster failure signal to an electronic controller(ECU), the operation state of a brake pedal 1 is inputted as a brake switch signal to the same, and based on these inputted signals, the motor 10 of an antilock control pump 9 is driven, a cut valve 25 is simultaneously closed and a power supply valve 24 is opened. Thus, brake fluid from a master cylinder 3 and the pressure increase ratio of a wheel cylinder with respect to an inputted pressure from the master cylinder 3 are adjusted by a balance valve 11.

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 hydraulic booster described above, for example, when an engine trouble occurs during running and the engine stops, or when the accumulator for the booster fails, the hydraulic booster is doubled. The power function will not work properly. 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 provides a conventional brake device having an anti-lock control modulator, which activates a pump in the anti-lock control modulator when an engine trouble or a failure occurs in a brake booster or the like. Accordingly, it is an 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 activates an anti-lock control pump in an anti-lock control modulator upon detecting the occurrence of the above-mentioned fault, and simultaneously operates the hydraulic pressure in the wheel cylinder and the master cylinder fluid when the pump operates. By adjusting the pressure with a balance valve newly provided in the circuit, an extremely safe brake fluid pressure control device can be obtained. Further, since the pump in the antilock control modulator is effectively used, it is advantageous in terms of cost.

[0007]

The technical solution adopted by the present invention is a control valve device for selectively connecting a wheel cylinder to either a master cylinder or a suction port of a pump, and a discharge port of the pump. A brake fluid pressure control device having a fluid recirculation type antilock control device having a recirculation path connecting the master cylinder and a master cylinder, wherein a normally open cut valve is provided between the master cylinder and the fluid pressure control valve device, A power supply valve for supplying the brake fluid of the master cylinder to the pump by being opened, and a discharge pressure of the pump with respect to the pressure of the master cylinder provided in the recirculation path. A balance valve that adjusts to a predetermined relationship, and a discharge port of the pump is connected to a cut valve and a control valve device. A brake fluid pressure control apparatus having a supply passage that connects the passage.

[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 block diagram of one system side of a brake fluid pressure control device according to a first embodiment. In FIG. 1, reference numeral 1 denotes a brake pedal as a brake operating member;
Is a brake booster (first booster), 3 is a tandem master cylinder, and two pipe routes 4, 5 for the front and rear wheels are provided from the tandem master cylinder,
Wheel cylinders 7 are connected to the ends of the pipe paths 4 and 5, respectively. In a piping path 4 between the tandem master cylinder 3 and the wheel cylinder 7, a hold valve 21, a decay valve 22, an antilock control reservoir 23, a hydraulic pump 9, a motor 10, a pulsation absorbing A conventionally known liquid circulation type antilock modulator (A) comprising a damper 8 and an orifice 8a
BS apparatus) B, and a second booster A, which is a feature of the present invention, is arranged between the ABS apparatus B and the master cylinder 3. The second booster A shares the hydraulic pump 9 and the pulsation preventing damper 8 in the ABS device B as shown in the figure, and is provided with a power supply valve 24, a cut valve 25, and a balance valve 11 separately from these. I have.

The first booster (brake booster)
2, the master cylinder 3, and the wheel cylinder 4 have the same configuration as the conventionally known ones. Further, in this example, the ABS device B is provided for each system, but the ABS device B is common to the front wheels, rear wheel independent, or Various forms, such as one side front and rear wheels, can be adopted. An electronic control unit (ECU) for controlling the second booster A is common to the ABS unit B. The electronic control unit (ECU) includes various sensors including a speed sensor used for conventional antilock control. In addition to the above signal, a signal from a sensor for detecting a failure of the brake booster (for example, detecting an accumulator pressure), an L terminal for detecting an engine stop (the voltage drops due to the engine stop), and a depression of a brake pedal are detected. Brake switch signal to be input.

Hereinafter, the second booster A will be described in more detail with reference to FIG.
A cut valve 25 is provided between the hold valve 21 in the BS device B and the cut valve 25,
A power supply valve 24 and first and second checks are provided in a pipe parallel to the hold valve 21 and the decay valve 22 (in other words, a pipe between the master cylinder 3 and an input port of the hydraulic pump 9 in the ABS device). Valve 26,
27 is provided as shown. ABS device B
A balance valve 11 is provided in an annular flow path connecting the discharge port of the pump 9 and the master cylinder 3 as shown in FIG. Further, a supply path 31 is connected between the pulsation preventing damper 8 and the balance valve 11, and the supply path 31 communicates with a pipe between the cut valve 25 and the hold valve 21.

The cut valve 25 is configured as a normally-open two-position switching valve. The cut valve 25 is provided with a fail-safe check valve 25a. It is configured to switch to the closed state according to a command from an electronic control unit (ECU). The power supply valve 24 is a normally closed type 2
The power supply valve 24 is configured as a position switching valve.
Is configured to be switched to a closed state by a command from an electronic control unit (ECU) in the same manner as the switching of the cut valve 25 described above. The first check valve 26 has a function of permitting the flow of fluid from the master cylinder to the hydraulic pump 9 side, and the second check valve 27 has a function of controlling the hydraulic pressure from the antilock control reservoir 23 in the ABS device B. It has a function of allowing the flow of fluid toward the input port of the pump 9.

The balance valve 11 is provided with a stepped piston 13 slidably in a two-stage cylinder 12 having different inner diameters, and a large diameter portion 12a of the cylinder 12 has a large diameter portion ( The first hydraulic chamber 14 and the second hydraulic chamber 15 are partitioned by the pressure receiving area A1). The first hydraulic chamber 14 communicates with the master cylinder, and the second hydraulic chamber communicates with the discharge port of the hydraulic pump. Further, inside the small diameter 12b of the cylinder 12, an atmosphere chamber 16 is defined by a small diameter portion (pressure receiving area A2) of the stepped piston 13. A spring 17 for urging the stepped piston 13 upward in the drawing is provided in the atmosphere chamber 16. A valve storage chamber 13 a is formed at the center of the stepped piston 13, and the valve storage chamber 13 a communicates with the first hydraulic chamber 14 and the second hydraulic chamber 15 by a flow path 13 b formed in the stepped piston 13. Further, a valve 19 that can maintain the flow path 13b in an open state by abutting on an engaging rod 18 provided on the cylinder side is disposed in the valve storage chamber 13a. This valve 19 is a valve spring 20
The valve 13 is biased toward the valve seat 13c formed in the flow path 13b by the contact. When moving leftward from the state of FIG. 1 against the urging force, the flow path 13b can be closed by the valve 19.

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 hydraulic cylinder 2, and the hydraulic pressure passes through the cut valve 25 of the second booster A disposed in the pipe 4 and the hold valve in the ABS apparatus B. 21 through the wheel cylinder 7
Is transmitted to the brakes. When the brake pedal 1 is released, the hydraulic pressure in the wheel cylinder 7 flows back 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. Since the mode of this antilock control is the same as that of the conventional one, detailed description is omitted here.

At the time of a fault When an engine trouble or a fault occurs in an accumulator or the like during running, and the brake pedal is depressed in that state, the engine status changes via an L terminal signal, and the accumulator pressure in the first booster is increased. If the condition is a brake booster failure signal,
Further, the brake pedal operation state is input to the electronic control unit (ECU) as a brake switch signal. Based on these signals, the motor M of the hydraulic pump is driven by a command from the electronic control unit, and at the same time, the cut valve 25 is closed. Then, the power supply valve 24 is opened. When the failure pump 9 is driven, the brake fluid from the master cylinder 3 is pumped up through the open power supply valve 24 → the first check valve 26 → the input port of the hydraulic pump 9 to increase the pressure, thereby preventing pulsation. The pulsation is absorbed by the damper 8, and is further supplied to the wheel cylinder 7 through the hold valve 21 opened through the supply path 31 to operate the brake. At this time, the pressure increase ratio of the wheel cylinder 7 to the input pressure from the master cylinder 3 is controlled by the balance valve 11 as follows.

That is, when the hydraulic pressure generated in the master cylinder 3 exceeds a predetermined value, the stepped piston 13 resists the urging force of the spring 17 due to the hydraulic pressure acting on the first hydraulic chamber 14 in the balance valve 3. The valve 19 contacts the valve seat 13c to close the flow path 13b. In this state, the valve 19 functions as a one-way valve that allows the flow of the brake fluid from the master cylinder 3 to the wheel cylinder 7 side.

Here, the relationship between the hydraulic pressure at the time when the balance valve 11 is closed and the force of the spring 17 will be described. The hydraulic pressure in the first hydraulic chamber 14 is P1, and the hydraulic pressure in the second hydraulic chamber 15 is P1. P
2. Assuming that the force of the spring 17 is F, the pressure receiving area of the large diameter portion of the stepped piston 13 is A1, and the pressure receiving area of the small diameter portion of the stepped piston is A2, P1 · A1 = P2 · (A1−A2) + F ( 1) Here, P1 = P2 when the valve is closed. Therefore, when the above equation (1) is arranged, the hydraulic pressure P1 when the valve is closed is obtained.
Is P1 = F / A2. Thereafter, when the discharge pressure from the hydraulic pump 9 (in other words, the hydraulic pressure on the wheel cylinder side) increases after the flow path 13b in the balance valve 11 is closed, the second hydraulic chamber 1
The hydraulic pressure P2 in 5 also increases. Hydraulic pressure P in that case
The relationship between P1 and P2 can be expressed by the following expression by rearranging expression (1). P2 = [(P1 · A1) −F] / (A1−A2) Thus, even when the hydraulic pump 9 is operated,
Since the balance valve 11 increases the pressure of the wheel cylinder 7 in a predetermined relationship with respect to the input pressure from the master cylinder 3, a brake pressure corresponding to the hydraulic pressure of the master cylinder 3 can be obtained. Also, at the time of booster pedal return, the wheel cylinder pressure corresponding to the master cylinder pressure can be obtained by the boost ratio determined by the area ratio of the balance valve 11 as in the case of pressurization.

As described above, in the present brake fluid pressure control device, the second booster does not operate in a normal state, but the brake booster may fail for some reason during running.
When the brake pedal 1 is operated with the engine stopped, the cut valve 25, power supply valve 2
4. By operating the hydraulic pump 9 in the ABS device B, a wheel cylinder pressure corresponding to the master cylinder can be obtained at a boost ratio determined by an area ratio of the balance valve 11,
When the brake pedal 1 is released, the hydraulic pump 9 stops, and the cut valve 25 and the power supply valve 24 return to the initial state. It returns to the cylinder 3 and the brake is released. If the wheels tend to lock during the normal or abnormal braking operation, a sensor (not shown) detects this as in the conventional device, and operates the ABS device in response to a command from the electronic control device to activate the brake fluid. Control pressure to avoid wheel locking tendency.

Next, a description will be given of a second embodiment. FIG. 2 is a configuration diagram of the second embodiment. The second embodiment is the first
The embodiment is characterized in that a slope start assist function is added, and as shown in FIG.
A normally-closed shut valve 30 is provided in a pipe between the second hydraulic chamber 15 and the branch point of the supply path 31. Although the electronic control unit is of a type that can newly input a gear engagement signal, a clutch connection signal, and the like for starting on a slope, the function of the electronic control unit is the same as that of the first embodiment. In the second embodiment, as in the first embodiment, when the brake booster 2 fails during driving or when the brake switch is turned on while the engine is stopped, as shown in FIG. 9 operates, at the same time, the cut valve 25 is closed, the power supply valve 24 is opened, and when the shut valve 30 is opened, the liquid discharged from the hydraulic pump 9 operates the hold valve 21 by the same operation as in the first embodiment. A wheel cylinder pressure corresponding to the master cylinder can be obtained at a boost ratio determined by the area ratio of the balance valve 11.

When the vehicle is stopped and the brake pedal is kept depressed for a predetermined time (several seconds) when the vehicle starts on a slope, the state is detected by a sensor, and a cut valve as shown in FIG. 25, the power supply valve 24 is closed, and the shutoff valve 30 is further closed to confine the brake fluid pressure in the wheel cylinder. After this state, the braking force is maintained even when the brake pedal is released. When the vehicle is started from this state (for example, when a gear input signal and a clutch connection signal are input to the electronic control unit), the cut valve 25 is automatically opened by a command from the electronic control unit, and the brake fluid is opened. The pressure is released to the master cylinder, and the vehicle can easily start on a slope. Thus, an inexperienced driver can easily start on a slope without performing complicated clutch and brake operations. The hill start state can be detected from various states of the vehicle, and the valves can be controlled by the electronic control device by appropriately combining them. As described above, according to the present invention, even if a brake booster fails during traveling or the engine is stopped, the brake is applied by the second booster without changing the pedal feeling so much as before the failure. Can increase safety. In addition, even an inexperienced driver can easily start on a sloping road simply by adding a shut valve. Note that the slope start assist function can also be used for automatic braking when the vehicle is temporarily stopped, such as when a signal is stopped. In this case, a signal required for that purpose is input to the electronic control unit. In each of the above embodiments, the second booster is arranged in two brake piping systems using a tandem master cylinder, but it is needless to say that the second booster can be applied to a single brake system.

[0020]

As described in detail above, according to the present invention,
If the brake booster fails during driving or the engine stops, the hydraulic pump in the ABS device in the second booster operates, and the master pump is operated by the hydraulic pressure from this pump and the balance valve. A wheel cylinder pressure corresponding to the cylinder can be obtained, and a highly safe brake fluid pressure control device can be obtained. Further, by adding a shut valve, even an inexperienced driver can easily start on a slope. Further, by sharing the hydraulic pump in the ABS device, it is possible to achieve excellent effects such as the whole system can be configured at low cost.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a brake fluid pressure control device according to a second embodiment.

FIG. 3 is a configuration diagram showing a state in which a failure has occurred in a second embodiment and a hydraulic pump has been operated.

FIG. 4 is a configuration diagram showing a state at the time of starting on a slope in the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 brake pedal 2 brake booster 3 tandem master cylinder 4 piping 7 wheel cylinder 8 pulsation prevention damper 9 hydraulic pump 10 motor 11 balance valve 21 hold valve 22 decay valve 23 reservoir for antilock control 24 power supply valve 25 cut valve 26 , 27 Check valve 30 Shut valve 31 Supply path

Claims (2)

[Claims] A liquid recirculation type having control valve devices for selectively connecting a wheel cylinder to either a master cylinder or a suction port of a pump, and a recirculation path connecting the discharge port of the pump and the master cylinder. In a brake fluid pressure control device having an anti-lock control device, a normally-open cut valve 25 is provided between the master cylinder and the fluid pressure control valve device, and is provided between the master cylinder and a suction port of the pump. A power supply valve 24 for supplying the brake fluid of the master cylinder to the pump by being opened, a balance valve provided in the recirculation path for adjusting the discharge pressure of the pump with respect to the pressure of the master cylinder to a predetermined relationship, And a supply passage 31 connecting the discharge port of the cut valve 25 to a passage connecting the control valve device 21 to the cut valve 25. Equipped brake fluid pressure control device. 2. The brake fluid pressure control device according to claim 1, wherein a normally closed shut valve is provided between a discharge port of the pump and the balance valve.