JPH10305770A - Pressure accumulation control method of accumulator of brake fluid circuit for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce pressure accumulating noise by driving a pump by making a second switching valve 2 arranged between the side of a master cylinder of a main hydraulic pressure circuit and the suction side of a pump device of a return hydraulic pressure circuit a closing state, making the second switching valve after the driving is stopped a closing state and performing pressure accumulation for brake fluid by inertia force of the pump device. SOLUTION: When a pressure accumulation is performed for brake fluid in an accumulator 40, a second switching valve 53 is made a closing state at first and brake fluid is not supplied from a master cylinder 12 to the suction side of a pump. Because a motor 17 is turned on, a pump 16 is driven and brake fluid is not supplied to the suction side, load of the pump 16 and the motor 17 does not exist and generation of noise can be reduced. Next, when the second switching valve 53 is made an opening state and brake fluid is supplied from the master cylinder 12 to the suction side of the pump 16, the pump 16 continues the operation and brake fluid supplied to the suction side of the pump 16 is pumped up to a discharge side by inertia force of the motor 17 and the pump 16, even if the power of the motor 17 is turned off. Namely, pressure accumulating noise can be reduced by utilizing inertia force of the pump device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake hydraulic circuit for a vehicle.

[0002]

2. Description of the Related Art Conventionally, a pressure accumulator has been provided and accumulated in a pressure accumulator in order to secure a rising speed of a brake fluid pressure of a wheel cylinder when a traction control control (TCS) or a vehicle behavior control is operated. Supply brake fluid to wheel cylinders quickly. Therefore, before these control operations, it is necessary to drive the pump in advance and accumulate the brake fluid in the accumulator.

However, the conventional method has the following problems. <B> When the motor is driven to operate the pump and the brake fluid is stored in the pressure accumulator, the motor generates pressure accumulation noise.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to reduce accumulation noise.

[0005]

SUMMARY OF THE INVENTION The present invention provides a main hydraulic circuit for supplying brake fluid from a master cylinder to a wheel cylinder through an inlet valve, and a main hydraulic circuit from the wheel cylinder via an outlet valve and a pump device. Return hydraulic circuit to return to,
An accumulator connected to the discharge side of the pump device of the return hydraulic circuit via the first switching valve, and disposed between the master cylinder side of the main hydraulic circuit and the suction side of the pump device of the return hydraulic circuit. A second switching valve, wherein the brake fluid discharged from the pump device is supplied to the pressure accumulator through the first switching valve, and the accumulated brake fluid is supplied to the wheel cylinder. (2) The pump device is driven by closing the switching valve, the driving of the pump device is stopped, the second switching valve is opened, and the brake fluid is accumulated in the accumulator by the inertia force of the pump device. A method for controlling the accumulation of pressure in an accumulator of a vehicle brake hydraulic circuit, or a main hydraulic circuit for supplying brake fluid to a wheel cylinder through an inlet valve from a master cylinder, and an outlet valve and a pump device from a wheel cylinder. Main liquid A return hydraulic circuit returning to the circuit, an accumulator connected to a discharge side of a pump device of the return hydraulic circuit via a first switching valve, a pump device of a master cylinder side of the main hydraulic circuit and a return hydraulic circuit The second disposed between the suction side of
A switching valve, wherein the brake fluid discharged from the pump device is supplied to the pressure accumulator via the first switching valve, and the stored brake fluid is supplied to the wheel cylinder. , The motor is turned on, the motor is turned off, and then the second switching valve is opened to accumulate the brake fluid in the accumulator. In the control method.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

<A> Outline of Vehicle Brake Hydraulic Circuit In a vehicle brake hydraulic circuit, hydraulic pressure generated by a hydraulic unit 20 is applied to each wheel cylinder 14 of a front wheel and a rear wheel as shown in FIG. The braking is applied to each of the wheels (the front left wheel 102, the front right wheel 103, the rear left wheel 104, and the rear right wheel 101). For example, in a brake control such as a traction control system (TCS), a vehicle behavior control system, or an anti-lock brake control system (ABS), when a wheel slips or the vehicle behaves abnormally, the wheel speed sensor 31 and various other sensors (for example, fluid) Pressure sensor 32, G sensor 3
3, yaw rate sensor 34, steering angle sensor 3
5. The electronic control unit 30 controls the hydraulic unit 20 based on signals from the engine sensor 38) and various switches (for example, the fluid amount switch 36, the hydraulic switch 37, and the stroke switch 41) to control the wheels. Optimal brake control is performed. At the same time, optimal torque control is also performed on the engine unit 39. The electronic control unit 30
May have the configuration of a dedicated hardware device or a general computer device such as a microcomputer.

<B> Outline of Hydraulic Unit The hydraulic unit 20 is shown in FIG.
An example of all the wheels is shown in FIG. 3 and functions as a hydraulic circuit such as a traction control system (TCS), a vehicle behavior control system, or an antilock brake control system (ABS). FIG. 3 shows an example of the X pipe. One main hydraulic circuit 21 has a left front wheel 102 and a right rear wheel 1.
The right front wheel 103 and the left rear wheel 104 are connected to the other independent main hydraulic circuit 21.

The hydraulic unit 20 includes a master cylinder 12
A main hydraulic circuit 21 for connecting the brake fluid to the wheel cylinder 14, a return hydraulic circuit 22 for returning the brake fluid to the main hydraulic circuit 21 by the pump 16, an auxiliary hydraulic circuit 23 for supplying the brake fluid directly from the master cylinder 12 to the pump 16, A pressure accumulator hydraulic circuit 24 for supplying brake fluid to the accumulator 40 is provided. A valve (valve) is disposed in each hydraulic circuit, and the opening and closing of the circuit is controlled so that a predetermined brake is applied to each wheel 10. Control. A check valve 19 is provided in the hydraulic circuit to prevent backflow and ensure safety.

<C> Main Hydraulic Circuit The main hydraulic circuit 21 is a flow path for brake fluid between the master cylinder 12 and the wheel cylinder 14, and a third switching valve 50 and an inlet valve 51 are arranged in this flow path. And the third switching valve 50
A main hydraulic pressure limit valve 55 is arranged in parallel with the main hydraulic pressure limit valve 55. The third switching valve 50 is a valve that switches between opening and closing the passage of the brake fluid.

<D> Return hydraulic circuit The return hydraulic circuit 22 is a flow connecting the main hydraulic circuit 21 between the wheel cylinder 14 side (point C), the third switching valve 50 and the inlet valve 51 (point B). And an outlet valve 52 in this flow path.
An auxiliary reservoir 15, a pump 16, and a damping chamber 18 are arranged. The pump 16 is driven by a motor 17. The hydraulic pressure is applied to the brake fluid by the action of the pump 16 and the brake fluid is discharged to the damping chamber 18 side. The damping chamber 18 absorbs fluctuations in the brake fluid pressure and is arranged as necessary. Return hydraulic circuit 2
2 is, for example, opening the outlet valve 52 to open the wheel cylinder 14
The brake fluid can be taken into the auxiliary reservoir 15 and returned to the main hydraulic circuit 21 by the action of the pump 16.
A device having the functions of the pump 16 and the motor 17 is referred to as a pump device.

<E> Auxiliary Hydraulic Circuit The auxiliary hydraulic circuit 23 connects the main hydraulic circuit 21 to the master cylinder 12 (point A) and the return hydraulic circuit 22 to the suction side (point D) of the pump 16. The second switching valve 53 is disposed on the way. The second switching valve 53 is a valve that switches between opening and closing of the passage for the brake fluid. The auxiliary hydraulic circuit 23 can supply the brake fluid from the master cylinder 12 to the suction side of the pump 16 by opening the second switching valve 53.

<F> Accumulator hydraulic circuit The accumulator hydraulic circuit 24 is a passage connecting the discharge side of the pump 16 in the return hydraulic passage, for example, the damping chamber 18 and the accumulator 40, and a first switching valve 54 in the middle. Is arranged.

When accumulating pressure in the accumulator 40, the third switching valve 5
0, the inlet valve 51 is closed, the second switching valve 53 is opened,
The brake fluid is supplied to the pump 16, and the brake fluid is accumulated in the pressure accumulator 40 from the discharge side of the return hydraulic circuit 22 through the opened first switching valve 54 by the action of the pump 16.

A stroke switch 41 is attached to the pressure accumulator 40. When a prescribed amount of brake fluid is accumulated, the switch 41 operates to stop accumulating the pressure in the pressure accumulator 40. Acts to accumulate pressure.

The brake fluid accumulated in the accumulator 40 is supplied to the wheel cylinder 14 by opening the first switching valve 54.

With regard to the pressure accumulation of the pressure accumulator 40, the brake fluid pressure of the wheel cylinder 14 is increased at a high speed by accumulating the pressure so that the brake fluid pressure can always be sufficiently supplied to the wheel cylinder 14 even during times other than the discharge stroke of the pump 16. Can be realized.

The operation of the brake hydraulic circuit will be described below.

<A> Accumulation of Brake Fluid in Accumulator In a normal state, that is, a state where the brake is not depressed, a state where traction control is not performed, and a state where the vehicle does not behave abnormally, The specified amount of liquid is stored. Accumulation of the brake fluid in the accumulator 40 is performed in the normal state. For example, the pump device is driven, that is, the motor is switched on, the pump is driven, and after a short time drive, the switch is turned off. The operation of the pump device is maintained by the inertia force, the third switching valve 50 is closed and the second switching valve 53 is opened, and the brake fluid stored in the main reservoir 13 is supplied from the master cylinder 12 to the suction side of the pump 16. Supplied to The brake fluid is pumped into the damping chamber 18 by the inertial force of the pump device. At this time, the third switching valve 50
And the inlet valve 51 are closed.
4, the brake fluid is stored in the pressure accumulator 40. When the pressure accumulator 40 accumulates a predetermined amount of brake fluid, the stroke switch 41 operates to end the pressure accumulating operation and close the first switching valve 54.

<B> Method of controlling the accumulation of brake fluid in the accumulator When the pump device is driven, the second switching valve 53 is closed, and the brake fluid is not supplied from the master cylinder 12 to the suction side of the pump device. As a result, since almost no load is applied to the pump device, noise generated from the pump device can be reduced. When pumping the brake fluid with the pump device, the driving of the pump device is stopped, the second switching valve 53 is opened, the brake fluid is supplied to the pump device, and the pumping device performs the inertial force. As a result, noise does not occur even when the pump device operates to pump up the brake fluid.

FIG. 4 shows this flowchart. When accumulating the brake fluid in the accumulator 40, first, the second switching valve 53 is closed (S1). Therefore, the brake fluid is not supplied from the master cylinder 12 to the suction side of the pump. next,
Turn on the motor 17, drive the pump 16 (S2),
Thereafter, the motor 17 is turned off after a predetermined time, for example, 35 ms (S3). During the operation of the pump 16, no brake fluid is supplied to the suction side of the pump 16, so that almost no load is applied to the pump 16 and the motor 17, and the generation of noise can be reduced. Next, the second switching valve 53 is opened (S4), and the brake fluid is supplied from the master cylinder 12 to the suction side of the pump 16. Even if the power of the motor 16 is turned off, the pump 16 continues to operate by the inertia of the motor 17 and the pump 16, and pumps the brake fluid supplied to the suction side of the pump 16 to the discharge side. The off time of the motor 17 is
It is determined by various conditions such as the capacity of the motor 17, the pump 16, and the accumulator 40, and is set to, for example, 400 ms. If pressure accumulation is still necessary, the process returns to step S1, and the same processing is performed (S5).

FIG. 5 shows the driving and output states of the motor 17. At time t1, the second switching valve 53 is closed, and at time t2
To turn on the power switch of the motor 17. Motor 17
Is 100% and the pump 16 is sufficiently driven. For example, at time t3 after 35 ms, the motor 17
Is turned off, and the driving of the motor 17 is stopped. Motor 17
And the pump 16 are operated by inertial force, and in this state, t4
At the time, the second switching valve 53 is opened. If the accumulation in the accumulator 40 is still necessary, this control pattern is repeated.

<C> Operation of the Brake Fluid Circuit During Normal Braking In a normal braking operation, the third switching valve 50 and the inlet valve 51
Are open, and the second switching valve 53 and the outlet valve 52 are closed. Therefore, the hydraulic pressure generated in the master cylinder 12 when the brake pedal 11 is depressed passes through the main hydraulic circuit 21 and is applied to the wheel cylinder 14 so that the wheel 10 is braked. When you release the brake pedal,
Since the hydraulic pressure generated in the master cylinder 12 decreases, the brake pressure of the wheel cylinder 14 also decreases.

<D> Operation of brake hydraulic circuit during brake control For example, in brake control such as traction control, vehicle behavior control and antilock brake control, the pressure accumulator 40
Is supplied to the wheel cylinder 14. In particular, in the traction control and the vehicle behavior control, the brake fluid may not be sufficiently supplied to the suction side of the pump 16 of the return hydraulic circuit 22 and the pressure of the wheel cylinder 14 may be increased slowly. 14 to increase the pressure. Therefore, when the first switching valve 54 is opened, the brake fluid accumulated in the accumulator 40 can be rapidly supplied to the wheel cylinder 14.

This brake fluid pressure is used for traction control,
The opening / closing control of the inlet valve 51 and the outlet valve 52 according to the brake control such as the vehicle behavior control and the antilock brake control is applied to the wheel cylinder 14 and the optimum brake control is performed.

[0026]

According to the present invention, the following effects can be obtained. <B> By using the inertial force of the pump device, it is possible to reduce the accumulated noise generated when accumulating the brake fluid in the accumulator.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a brake control.

FIG. 2 is a brake hydraulic circuit diagram for one wheel.

FIG. 3 is a brake hydraulic circuit diagram for four wheels.

FIG. 4 is a flowchart of a pressure accumulation control.

FIG. 5 is a time chart of the pressure accumulation control.

[Explanation of symbols]

 12, master cylinder 14, wheel cylinder 16, pump 19, check valve 20, hydraulic unit 21, main hydraulic circuit 22, return hydraulic circuit 23, auxiliary hydraulic circuit 24, accumulator Hydraulic circuit 30 Electronic control unit 40 Accumulator 41 Stroke switch 50 Third switching valve 51 Inlet valve 52 Outlet valve 53 Second switching valve 54 First switching valve 55 ・ ・ Main hydraulic pressure limit valve

Claims (2)

[Claims] A main hydraulic circuit for supplying brake fluid from the master cylinder to the wheel cylinder via an inlet valve; a return hydraulic circuit for returning from the wheel cylinder to the main hydraulic circuit via an outlet valve and a pump device; An accumulator connected to the discharge side of the pump device of the return hydraulic circuit via the first switching valve, and disposed between the master cylinder side of the main hydraulic circuit and the suction side of the pump device of the return hydraulic circuit. A brake fluid circuit for supplying the brake fluid discharged from the pump device to the pressure accumulator via the first switch valve and supplying the accumulated brake fluid to the wheel cylinder. (2) The pump device is driven by closing the switching valve, the driving of the pump device is stopped, the second switching valve is opened, and the brake fluid is accumulated in the accumulator by the inertia force of the pump device. , Vehicle shake Accumulator accumulator control method of key hydraulic circuit. A main hydraulic circuit for supplying brake fluid from the master cylinder to the wheel cylinder via an inlet valve; a return hydraulic circuit for returning from the wheel cylinder to the main hydraulic circuit via an outlet valve and a pump device; An accumulator connected to the discharge side of the pump device of the return hydraulic circuit via the first switching valve, and disposed between the master cylinder side of the main hydraulic circuit and the suction side of the pump device of the return hydraulic circuit. A brake fluid circuit for supplying the brake fluid discharged from the pump device to the pressure accumulator via the first switch valve and supplying the accumulated brake fluid to the wheel cylinder. (2) accumulating brake fluid in a pressure accumulator by closing a switching valve to turn on a motor, turning off the motor, and then opening a second switching valve to accumulate brake fluid in an accumulator; Pressure control of vessel Law.