JP2558051Y2 - Hydraulic braking system for vehicles - Google Patents

Description

The present invention relates to a hydraulic brake system for a vehicle.

2. Description of the Related Art A brake fluid pressure of the wheel brake device is provided in a brake line connecting a master cylinder and a wheel brake device, and receives a command from a control unit that evaluates a braking slip and / or a drive slip of a wheel. A hydraulic pressure control valve for controlling, a reservoir for storing brake fluid discharged from the wheel brake device through the hydraulic pressure control valve when the brake fluid pressure is reduced by controlling the hydraulic pressure control valve; and A hydraulic pump that pressurizes brake fluid and supplies it to the wheel brake device side via a supply line; and a liquid pump disposed in the supply line that can shut off fluid communication from the hydraulic pump side to the wheel brake device side. In a vehicle hydraulic brake braking device having a first valve device, the reservoir comprises: a first reservoir that stores brake fluid in advance; A second valve device configured to include a storable second reservoir, a second valve device capable of shutting off liquid communication in a pipe connecting the two reservoirs, and connecting the second reservoir to the hydraulic pressure control valve; One in which the suction side of the hydraulic pump is connected to a reservoir has already been developed and disclosed in Japanese Patent Laid-Open No. 18153/1990.

In the conventional device as described above, when a drive slip occurs, a check valve device disposed in a pipe from the master cylinder to the hydraulic pressure control valve functions as a check valve. At the position B, the hydraulic pump is driven, whereby the brake fluid is sucked from the first reservoir on the master cylinder side to the hydraulic pump via the second valve device which is in a communicating state because the brake pedal is not depressed. In rare cases, it is supplied to the wheel cylinder of the front wheel, which is the driving wheel, through the hydraulic pressure control valve to apply braking force and reduce drive slip,
There is a problem that a response delay occurs from the detection of the driving slip to the application of the braking force to the driving wheels.

The present invention addresses such a problem.

Means for Solving the Problems The present invention provides a hydraulic brake system for a vehicle, which is provided with a hydraulic pipe of a two-diagonal system, and individually controls a brake hydraulic pressure supplied to each wheel brake device. A valve, a reservoir for each hydraulic piping system for storing brake fluid discharged from the wheel brake device when the brake hydraulic pressure is reduced by operation of the hydraulic pressure control valve, and a brake fluid in the reservoir for each hydraulic piping system A hydraulic pump that pressurizes and supplies a hydraulic pump to the upstream side of the hydraulic pressure control valve, and an actuator for braking slip control that shuts off a gap between the master cylinder and the hydraulic pressure control valve when the wheels are idling. A switching control valve for switching the downstream side of the hydraulic pressure control valve to a communication path for communicating two hydraulic pressure pipes; and a drive slip control actuator including an accumulator for accumulating hydraulic pressure provided in the communication path. Provided,
The hydraulic pressure supplied from the hydraulic pump for each hydraulic piping system during the drive slip control is stored together in the accumulator, and the hydraulic pressure stored in the accumulator is supplied to the wheel brake device during the next drive slip control. It is a feature.

Operation As described above, the rising characteristic of the brake hydraulic pressure due to the operation of the hydraulic pump can be improved in the next drive slip control.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the figure, 1 is a tandem type master cylinder, 2 is a master cylinder side reservoir for supplying brake fluid to the master cylinder 1, and 3 is a brake pedal connected to the master cylinder 1 via a booster such as a master back. Then, when the brake pedal 3 is depressed, the master cylinder 1 operates via the booster, and the left front wheel brake device 4a and the right rear wheel brake device
The hydraulic pressure is supplied to the wheel cylinder 5a and the hydraulic pressure is supplied from the other cross pipe B to the wheel cylinders of the right front wheel brake device 6a and the left rear wheel brake device 7a to apply the brake.

A brake slip control actuator 8 for controlling the brake fluid pressure for each wheel is interposed in both cross pipes A and B. The brake slip control actuator 8 detects a wheel speed of each wheel (not shown). The control unit (not shown) which generates a hydraulic pressure increase, hold, and pressure reduction signal based on each wheel speed signal described above is controlled by the pressure increase, hold, pressure decrease signal.

The brake slip control actuator 8 is interposed in a hydraulic pipe from the master cylinder 1 to the wheel brake device of each wheel for each wheel. When the amount of electricity to the solenoid is zero, the position becomes the a position, and the master cylinder moves to the wheel brake device. When the amount of current supplied to the solenoid is 1/2 of the rated current, the hydraulic pressure pipe from the master cylinder to the wheel brake device is shut off, and the amount of current supplied to the solenoid is equal to the rated current. At time c, the hydraulic pressure line from the master cylinder to the wheel brake device is cut off, and at the same time, four bypass pipes communicating with the cross piping system from the wheel brake device to the master cylinder side are connected.
The position type hydraulic pressure control valves 8a, 8a, 8a, 8a and the four three-position type hydraulic pressure control valves 8a, 8a, 8a, 8a are provided in parallel with each other, and the brake hydraulic pressure on the wheel brake device side is set in the master cylinder. The four check valves 8b, 8b, 8b, 8b, which pass when the brake fluid pressure is higher than the brake fluid pressure on the side, and the brake fluid pressure on the wheel brake device side, which is interposed in the bypass Two cross-pipe systems for each of the four cross-check systems, which are connected when the brake fluid pressure is higher than the brake fluid pressure, and a bypass pipe between the two check valves 8c, 8c of the cross-pipe A hydraulic pump 8d that returns the brake fluid stored in each wheel brake device to the master cylinder side when the three-position hydraulic pressure control valve 8a is switched to the side c that communicates the bypass pipe; 2 is installed in a bypass pipe extending from the hydraulic pump 8d to the wheel brake device side.
Reservoirs 8e, 8e and damper accumulators 8f, 8f interposed in series in a bypass pipe from the hydraulic pump 8d to the master cylinder side to prevent pulsation of brake hydraulic pressure. Have been.

Reference numeral 9 denotes a driving slip control actuator interposed in each of the cross pipes A and B. The driving slip control actuator 9 indicates a rotation state of a wheel generated by a wheel speed sensor installed on the wheel. The signal from the control unit which evaluates the idling state of the wheel by a signal and issues a signal cuts off both cross pipes A and B, and the cutoff causes the reservoirs 8e, 8e of the braking slip control actuator 8 to be controlled by pressure control described later. It is configured to communicate with the reservoir 2 on the master cylinder side via the valve 9b.

The drive slip control actuator 9 is interposed in both of the cross pipes A and B, and when the control unit evaluates that the accelerator pedal is not depressed and the wheels are not idling, the solenoid is not energized and the d position is When the control unit evaluates that the accelerator pedal is depressed and the wheels are idling, the solenoid is energized to the position e, and the master cylinder 1 moves to the position e. The hydraulic pipe to the wheel brake device is shut off, and the above-mentioned wheel brake devices are mastered via the pressure control valve 9b and the return pipe C which are opened when the hydraulic pressure from the wheel brake device becomes a predetermined value or more. Switching control valves 9a, 9a communicating with the cylinder side reservoir 2, the switching control valves 9a, 9a and the pressure control valve 9b. And an accumulator 9c for storing together the hydraulic pressure supplied from the hydraulic pump 8d for each piping system, and one of the reservoirs 8e, 8e of the braking slip control actuator 8, for example, the cross piping A The reservoir 8e from the reservoir 8e is interposed in the return pipe C extending to the master cylinder-side reservoir 2 and operates with the brake fluid pressure applied to the cross pipe A. When the brake fluid pressure is not applied, the reservoir 8e becomes the position f. And a switching valve 9d that communicates with the fluid passage of the return pipe C extending from the oil reservoir to the master cylinder side reservoir 2 and that is brought to a position g when the brake fluid pressure is applied to shut off the fluid passage.

In the above, at the time of braking when the brake pedal 3 is depressed, the hydraulic pressure generated in the master cylinder 1 is changed to the switching control valve 9a at the d position because the cross pipes A and B and the accelerator pedal are not depressed and the wheels are not running idle. It is introduced into the wheel brake devices of all the left, right, front and rear wheels via 9a to generate a braking force. At this time, the switching valve 9d is in the g position and shuts off the liquid passage communicating from the reservoir 8e to the master cylinder side reservoir 2. Therefore, the brake fluid does not flow into the reservoir 8e from the master cylinder side reservoir 2, and the hydraulic pressure is not disabled during the anti-skid operation. Locking during braking on a road surface having a low coefficient of road surface friction is controlled by a pressure reduction, hold, and pressure signal of a control unit that issues a pressure reduction, hold, and pressure signal of the brake fluid pressure based on a wheel speed signal of a wheel speed sensor. This is prevented by the operation of the braking slip control actuator 8.

When the accelerator pedal (not shown) is depressed, the switching control valves 9a and 9a are respectively set to the e position by the signal from the control unit which evaluates the idling state of the driving wheel by the driving force and outputs a signal.
The hydraulic piping to all the wheel brake devices is cut off for each cross piping system, and the pressure control valves are used for all the wheel brake devices.
9b, the switching valve 9d is set to the f position, and the reservoir 8e on the cross pipe A side of the braking slip control actuator 8 is communicated with the reservoir 2 on the master cylinder side. Of the return pipe C,
The brake fluid sucked into the hydraulic pump 8d via the switching valve 9d, the reservoir 8e on the side of the cross pipe A, and the check valve 8c is pressurized by the hydraulic pump 8d, and the check valve 8c, the accumulator for the damper. 8f, and a cross pipe A through a three-position hydraulic pressure control valve 8a, 8a at a position a by a signal issued from the control unit based on a wheel speed signal of a wheel speed sensor that detects that the drive wheel is over-rotating. In addition to the wheel braking devices 4a and 5a for the front left wheel 4 and the right rear wheel 5,
Wheel brake devices 6a for the right front wheel 6 and the left rear wheel 7 of the cross piping B system via the communication passage of the switching control valves 9a, 9a at the e position and the three-position hydraulic pressure control valves 8a, 8a at the a position. , 7a
In addition, a braking force is generated to prevent a drive slip. When the wheel speed decreases due to the braking force, various controls such as holding, depressurization, and pressurization of the brake fluid pressure are performed by a signal issued from the control unit based on the reduced wheel speed signal, and the maximum is within a limit that does not cause a drive slip. A three-position hydraulic pressure control valve which is at a position c from the wheel brake device belonging to each cross piping system by the operation of the hydraulic pressure pump 8d while the pressure reduction control is being performed.
8a, 8a, each cross piping system reservoir 8e, 8e, one check valve 8c,
The brake fluid sucked into the hydraulic pump 8d through 8c is provided with hydraulic pressure, and is transmitted through the other check valves 8c, 8c and the switching control valves 9a, 9a at the damper accumulators 8f, 8f, e. The hydraulic pressure stored in the accumulator 9c is supplied to the wheel brake device belonging to each cross piping system at the next drive slip control, so that the hydraulic pressure pump
The rising characteristic of the brake fluid pressure by the operation of 8d can be improved.

In the above embodiment, the example in which the drive slip control is applied to a four-wheel drive vehicle has been described. However, in a front wheel drive vehicle, the three-position type hydraulic pressure control valve 8a of the driven wheel is switched to the b position to thereby control the wheel brake device of the drive wheel. Needless to say, the brake fluid pressure can be supplied only to the front wheel drive vehicle.

In the above-described embodiment, an example in which the present invention is applied to a hydraulic braking device having a braking slip control actuator and a driving slip control actuator has been described. Needless to say, the present invention can be applied to an automatic braking device that is provided with a distance sensor that measures a distance therebetween and that automatically performs braking control so that the distance detected by the distance sensor has a certain set value.

Further, by setting a pressure accumulation mode in which the hydraulic pressure stored in the accumulator is further increased by the operation of the hydraulic pump, the pressurization responsiveness at the time of pressurization by the hydraulic pump may be improved by the above-described pressure accumulation. .

Advantageous Effects of the Invention As described above, according to the present invention, a hydraulic brake system for a vehicle includes a hydraulic pipe of a two-diagonal system and individually controls brake hydraulic pressure supplied to each wheel brake device. A pressure control valve, a reservoir for each hydraulic piping system storing brake fluid discharged from the wheel brake device when the brake hydraulic pressure is reduced by the operation of the hydraulic pressure control valve, and a reservoir for each hydraulic piping system. A brake slip control actuator having a hydraulic pump that pressurizes and supplies brake fluid to the upstream side of the hydraulic pressure control valve as a main element, and shuts off between the master cylinder and the hydraulic pressure control valve when the wheels are idling. A switching control valve for switching a downstream side of the hydraulic pressure control valve to a communication path for communicating two hydraulic pressure pipes; and a drive slip control actuator including an accumulator provided in the communication path for accumulating hydraulic pressure. The hydraulic pressure supplied from the hydraulic pump for each hydraulic piping system during drive slip control is stored together in the accumulator, and the stored hydraulic pressure is supplied to the wheel brake device during the next drive slip control. This makes it possible to improve the rising characteristic of the brake hydraulic pressure due to the operation of the hydraulic pump at the next drive slip control, that is, the pressurization response, and can bring a great effect in practical use in combination with the simplification of the configuration. It is.

[Brief description of the drawings]

FIG. 1 is a piping diagram of a hydraulic brake system for a vehicle, showing an embodiment of the present invention. 1 ... master cylinder, 2 ... master cylinder side reservoir, 3 ... brake pedal, 4, 6 ... front wheel, 5, 7 ... rear wheel, 8 ... brake slip control actuator, 9 ...
Actuator for drive slip control, 9a …… Switch control valve, 9b …… Pressure control valve, 9c …… Accumulator, 9d ……
Switching valve, A, B ... cross piping, C ... return piping.

Claims (1)

(57) [Scope of request for utility model registration] 1. A control unit, which is interposed in a diagonal two-system type hydraulic pipe from a master cylinder to a wheel brake device for each wheel and generates a signal based on a wheel speed signal from a wheel speed sensor, generates a signal based on the signal. A hydraulic pressure control valve for individually controlling a brake hydraulic pressure supplied to a wheel brake device for each wheel, and storing brake fluid discharged from the wheel brake device when the brake hydraulic pressure is reduced by operating the hydraulic pressure control valve A brake slip control actuator having a reservoir for each hydraulic piping system and a hydraulic pump for pressurizing the brake fluid in the reservoir for each hydraulic piping system and supplying it to the upstream side of the hydraulic pressure control valve as a main element; , Is interposed between the master cylinder of each hydraulic pipe of the diagonal two-system system and the brake slip control actuator, and receives a signal from a wheel speed sensor installed on the wheel. The signal of the control unit which detects and evaluates the idling state of the wheel and generates a signal cuts off the connection between the master cylinder and the hydraulic control valve of the brake slip control actuator, and the downstream side of the hydraulic control valve A hydraulic brake system for a vehicle, comprising: a switching control valve for switching to a communication passage for communicating a hydraulic pipe of a system; and a drive slip control actuator including an accumulator for accumulating hydraulic pressure provided in the communication passage.