JP2000177552A - Brake noise preventing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent brake noise by reducing the brake fluid pressure of a wheel from which brake noise is detected by a designated amount, and increasing the brake fluid pressure of the corresponding opposite wheel according to the pressure reducing amount by a designated fluid pressure amount. SOLUTION: Brake noise generated during brake operation is detected by microphones 8FLM, 8FRM, 8RLM, 8RRM provided on the respective wheels. A brake noise generating wheel is detected by a brake noise generating portion specifying means in an electronic control device 14. The brake fluid pressure of the brake noise generating wheel or a front or rear brake system is reduced by a designated amount, and the brake fluid pressure of the opposite wheel corresponding to the pressure reduced wheel or the brake fluid pressure of the opposite brake system corresponding to the reduced brake system is increased by a designated amount. Thus, the generation of brake noise can be prevented without changing the total braking force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing a brake noise generated when a brake is operated.
More specifically, by providing a means for detecting brake noise on each wheel and a means for controlling brake fluid pressure distribution for each wheel, when brake noise is detected, the four-wheel brake fluid pressure is adjusted to the most efficient hydraulic pressure. The present invention relates to a brake noise prevention device that can prevent brake noise by changing the distribution.

[0002]

2. Description of the Related Art Conventionally, in a vehicle brake device provided with means for controlling wheel brake fluid pressure, a rubber material is attached to a plate as a disk brake shim to prevent brake noise (brake noise). Things are well known. However, such a shim using rubber has a problem that the effect of preventing brake squeak for a long time is poor due to fatigue of the shim itself.

[0003]

In order to solve such inconvenience, Japanese Patent Laid-Open No. 9-221013 discloses that when brake squeal is detected by brake squeal detecting means, the distribution of front and rear brake fluid pressures is changed. Discloses a technique for suppressing brake noise. According to the above publication, when brake squeal is detected, the front and rear wheels are depressurized and the rear wheel brake fluid pressure is increased without reducing the front wheel brake fluid pressure without changing the total braking force of the front and rear wheels. The distribution of the brake fluid pressure is changed.
For example, when a brake squeal is generated from one side of the front wheel, the hydraulic pressure of the front wheel system is reduced, and the hydraulic pressure of the rear wheel system is increased so as not to change the total braking force of the front and rear wheels. For this reason, when such a brake distribution is used, the distribution before and after the brake of the normal vehicle is as follows: front wheel: rear wheel = 7:
Since it is about 3, for example, when ΔP is reduced in the front wheel system or the like, ΔP × 7/3 must be pressurized in the rear wheel system or the like, resulting in a large energy loss and a tendency to lock the rear wheel. There is a problem.

Therefore, the present invention provides a means for detecting brake noise on each wheel, and a four-wheel hydraulic pressure distribution function for the left, right, front and rear wheels of the brake. An object of the present invention is to solve the above problem by providing a noise prevention device capable of preventing brake noise by changing the distribution to the most efficient hydraulic pressure distribution. According to the present invention, the brake noise detection means provided on each wheel constantly monitors the brake squeal state of all four wheels, and if brake noise is detected on one of the left and right wheels of the vehicle (for example, the right front wheel), the brake noise is detected. Finely distributing brake fluid pressure by reducing the brake fluid pressure of the wheel by a predetermined amount and increasing the brake fluid pressure of the corresponding opposite wheel (left front wheel) by a predetermined fluid pressure according to the reduced pressure amount. Thus, the brake noise is prevented without changing the total braking force, and further reliably avoiding the tendency of the rear wheel system to lock.

[0005]

For this reason, the technical solution adopted by the present invention is a hydraulic brake system for a vehicle, comprising: brake noise detecting means for detecting brake noise provided on each of the left, right and front and rear wheels; A noise generation location specifying unit; and a hydraulic pressure distribution control unit that adjusts a hydraulic pressure distribution between the left and right front and rear wheels. The brake noise generating wheel is specified by an output signal from the brake noise detection unit. To reduce the pressure by a predetermined amount and to increase the brake hydraulic pressure of the wheel on the opposite side of the wheel corresponding to the left and right of the vehicle by a predetermined hydraulic pressure according to the reduced amount,
Further, when the brake noise detecting means detects brake noise of the front wheel system or the rear wheel system, the brake fluid pressure of the system generating the noise is reduced by a predetermined amount, and the brake fluid pressure of the remaining system is reduced by the reduced pressure amount. The brake noise prevention device is configured to increase the pressure by a predetermined hydraulic pressure according to the following.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an embodiment of the present brake pressure control device, and FIG. 2 is a block diagram of a brake noise control means. 3 is a configuration diagram of the hydraulic pressure adjusting device.

In FIG. 1, 1 is a brake pedal, 2 is a hydro booster, 3 is a tandem master cylinder,
4F is a front wheel switching valve, 4R is a rear wheel switching valve, 5FL
Is a hydraulic pressure adjusting device for the left front wheel, 5FR is a hydraulic pressure adjusting device for the right front wheel, 5RL is a hydraulic pressure adjusting device for the left rear wheel, 5R
R is the hydraulic pressure adjusting device for the right rear wheel, 6FLC is the wheel cylinder for the left front wheel, 6FRC is the wheel cylinder for the right front wheel, 6RLC is the wheel cylinder for the left rear wheel, 6RRC is the wheel cylinder for the right rear wheel, 7FLS, 7FRS, 7R
LS, 7RRS are hydraulic pressure sensors provided independently for each wheel, 8F
LM, 8FRM, 8RLM, 8RRM are noise sensors as brake noise occurrence detecting means provided independently for each wheel, 9 is a deceleration sensor, 10 is a pump, 11 is a check valve,
Reference numeral 12 denotes an accumulator, reference numeral 13 denotes a reservoir, and reference numeral 14 denotes an electronic control unit, which are connected to each other by a hydraulic circuit shown by a thick solid line, and connected to the electronic control unit by an electric circuit shown by a dotted line. Note that the English symbols after the numbers (for example, F, FL, FLC, FLS, FLM, etc.) correspond to the left and right sides of the vehicle, and those having the same numbers are parts having the same structure, and are necessary in the following description. These alphabetic symbols are omitted according to.

The switching valve 4, the fluid pressure adjusting device 5, the fluid pressure sensor 7, the noise sensor 8 and the like have the same structure. The switching valve 4 is configured as a normally open two-position switching valve, and brake noise prevention control is performed. Take A position when not done,
When the brake noise control is started, it is switched to the position B by a signal from the electronic control circuit. Further, in the electronic control unit 14, when the brake noise generation detecting means (microphone) detects the noise, the brake noise generating wheel specifying means in the electronic control unit 14 detects the brake noise generating wheel, and distributes the brake fluid pressure in a manner described later. The control means executes the brake fluid pressure distribution and executes the brake noise prevention control. FIG. 2 shows a control block diagram in the electronic control unit.

The hydraulic pressure adjusting device 5 has a configuration shown in FIG. 3, and is a known proportional valve capable of increasing the hydraulic pressure P in proportion to the current I as shown in FIG. The fluid pressure adjusting device 5
The housing 50 has an input port 51 communicating with the switching valve 4, an output port 52 communicating with the wheel cylinder, and a drain port 53 communicating with the reservoir 13, and a spool valve 54 is disposed in the housing 50.
The spool valve 54 includes a land portion 55 that communicates and shuts off the input port 51 and the output port 52, and a land portion 56 that communicates and shuts off the output port and the drain port. A second liquid chamber 58 is defined, and the first liquid chamber 57 and the second liquid chamber 58 are
Are communicated with each other by a flow path 59 provided in the first section. The spool valve 54 is slidably supported on the housing 50 by a bearing 60 and has a housing 50.
The housing 50 and the land 5
A seal member for liquid-tight sealing between the first and second housings 56 and 56 is provided, and an electromagnetic coil 61 is provided on the outer periphery of one end of the housing 50. In the figure, reference numeral 62 denotes a return spring.

When the hydraulic pressure adjusting device 5 is not operated, the spool valve 54 moves to the left from the state shown in the drawing to connect the input port 51 and the output port 52 and shut off the output port 52 and the drain port 53. Therefore, when not operating, the hydraulic pressure from the master cylinder 3 can be supplied to each wheel cylinder 6 via the switching valve 4 → the hydraulic pressure adjusting device 5. When a current flows through the electromagnetic coil 61,
The spool valve 54 outputs a predetermined hydraulic pressure while vibrating little by little to the left and right in the drawing so as to output a hydraulic pressure proportional to the current flowing through the electromagnetic coil 61. That is, when the pressure is reduced by the predetermined hydraulic pressure by the hydraulic pressure adjusting device 5, the spool valve 54 is moved in small increments as shown in the drawing to shut off the input port 51 and the output port 52, and communicate the output port 52 with the drain port 53. Then, the brake fluid pressure in the wheel cylinder is returned to the reservoir by a predetermined amount, and the predetermined hydraulic pressure is reduced. When the pressure is increased by the predetermined hydraulic pressure by the hydraulic pressure adjusting device 5, the spool valve 54 moves from the illustrated state to the left by a small amount, and communicates between the input port 51 and the output port 52 to adjust the hydraulic pressure from the accumulator 4 to a wheel. It is supplied into the cylinder 6 to increase the brake fluid pressure by a predetermined fluid pressure.

The microphone 8 is small and lightweight.
Various microphones available on the market can be used as long as they can detect the brake noise and can satisfy such requirements. Further, instead of the microphone 8, a vibration sensor that detects vibration that causes brake noise can be used.

In the above brake pressure control device, when the brake pedal 1 is operated, a predetermined hydraulic pressure is generated in the master cylinder 3 via the hydro booster 2, and this hydraulic pressure is applied to the normally open switching valve 4, the hydraulic pressure adjusting device. The brake is supplied to the wheel cylinder 6 via the brake 5. When the brake pedal 1 is released, the hydraulic pressure of the wheel cylinder 6 flows back to the master cylinder through the above-mentioned flow path to release the brake. The brake noise generated during the operation of the brake is detected by a microphone 8 provided for each wheel, and the brake noise generating wheel identifying means in the electronic control unit detects the brake noise generating wheel. To prevent the occurrence of Hereinafter, the mode of the brake noise prevention corresponding to each wheel will be described with reference to the drawings.

FIG. 5A shows the case where noise occurs in the left front wheel. When noise is detected by the microphone 8 and it is specified that the noise is generated from the left front wheel by the brake noise generation point specifying means in the electronic control unit, the brake fluid pressure of the left front wheel generating the noise is reduced. ΔP
And increase the brake fluid pressure of the right front wheel by ΔP.
The brake fluid pressures of the left and right rear wheel systems remain unchanged. Specifically, when the microphone 8 detects the noise of the front left wheel, and the electronic control unit specifies the location of the noise as the front left wheel, the switching valve 4F is switched to the position B by the brake fluid pressure distribution control means, and the noise of the front left wheel is detected. A predetermined current is caused to flow through the fluid pressure adjusting device 5FL to connect the output port 52 and the drain port 53, and the wheel cylinder 6FL has a fluid pressure proportional to the current.
Decrease the brake fluid pressure of C. At the same time, a predetermined current is supplied to the hydraulic pressure adjusting device 5FR of the right front wheel to connect the input port 51 and the output port 52, and a predetermined hydraulic pressure is supplied from the accumulator 12 into the wheel cylinder to reduce the brake hydraulic pressure by ΔP Increase pressure.

The brake noise is caused by the brake fluid pressure as a trigger factor of the noise generation. It has been confirmed that the noise generation disappears when the fluid pressure is reduced during the noise generation. Noise reduction can be eliminated by reducing the brake fluid pressure of the wheel that is present by ΔP. The total braking force is not changed by increasing the brake fluid pressure of the opposite wheel by ΔP. FIG. 5B shows a case where noises are simultaneously generated in the left and right front wheels at the same time. At this time, the brake fluid pressures of the left and right front wheels that are generating the noise are simultaneously reduced by ΔP, and the brake fluid pressures of the left and right rear wheels are reduced. For example, the pressure is increased by + 7 / 3ΔP corresponding to the distribution before and after the brake so that the total braking force is not changed. By setting the coefficient (+7/3) for the pressure increase in accordance with the distribution before and after the brake, the total braking force does not change.

FIG. 5C shows a case where noise is generated in the left rear wheel. At this time, the brake fluid pressure of the left rear wheel generating the noise is reduced by ΔP, and the brake of the right rear wheel is reduced. The hydraulic pressure is increased by ΔP, and the brake hydraulic pressures of the left and right front wheel systems remain unchanged. FIG. 5D shows a case where noise is simultaneously generated in the left and right rear wheels. At this time, the brake fluid pressure of the left and right rear wheels that are generating the noise is simultaneously reduced by ΔP, and the brake fluid pressure of the left and right front wheels is reduced, for example. The pressure is increased by + 3 / 7ΔP in accordance with the distribution before and after the brake so that the total braking force does not change. FIG. 5E shows a case where noise is simultaneously generated in the left front wheel and the right rear wheel. At this time, the brake fluid pressure of the left front wheel and the right rear wheel that is generating the noise is simultaneously reduced by ΔP, and The brake fluid pressure of the wheels and the right front wheel is increased by ΔP so that the total braking force remains unchanged. As described above, the present invention reduces the brake fluid pressure of the wheel or the front and rear brake system that has generated the brake noise by a predetermined amount, and the opposite wheel corresponding to the reduced wheel or the opposite brake corresponding to the reduced brake system. By increasing the brake fluid pressure of the system by a predetermined amount, occurrence of brake noise can be prevented.

[0016]

As described in detail above, according to the present invention,
The brake noise detection means provided for each wheel constantly monitors all the brake squeal conditions of the four wheels. If brake noise is detected on one of the left and right wheels (for example, the right front wheel), the wheel (the right front wheel) is detected. ), The brake fluid pressure is reduced by a predetermined amount, and the brake fluid pressure of the corresponding wheel (left front wheel) is increased by a predetermined hydraulic pressure in accordance with the reduced pressure amount, so that fine brake fluid pressure distribution is performed. By doing so, it is possible to achieve an excellent operation and effect that the brake noise can be surely prevented without changing the total braking force, and furthermore, the locking tendency of the rear wheel system is reliably avoided.

[Brief description of the drawings]

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

FIG. 2 is a control block diagram of brake noise prevention control.

FIG. 3 is a configuration diagram of a hydraulic pressure adjusting device.

FIG. 4 is a graph of the current of the hydraulic pressure adjusting device and the generated hydraulic pressure.

FIG. 5 is a table showing an embodiment of a brake noise prevention corresponding to each wheel by the present device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 brake pedal 2 hydro booster 3 tandem master cylinder 4 switching valve 5 fluid pressure adjusting device 6 wheel cylinder 7 fluid pressure sensor 8 noise sensor 9 deceleration sensor 10 pump 11 check valve 12 accumulator 13 reservoir 14 electronic control device

Claims (1)

[Claims] In a hydraulic brake system for a vehicle, a brake noise detecting means for detecting brake noise provided on each of the left and right front and rear wheels, a brake noise occurrence location specifying means, and a hydraulic pressure distribution for the left and right front and rear wheels are adjusted. A hydraulic pressure distribution control means for identifying a wheel on which a brake noise is generated by an output signal from the brake noise detecting means, reducing the brake fluid pressure of the identified wheel by a predetermined amount, and at the opposite side of the wheel corresponding to the left and right of the vehicle A system in which the brake fluid pressure of the wheels can be increased by a predetermined fluid pressure according to the reduced pressure amount, and a system that generates noise when the brake noise detecting means detects front-wheel or rear-wheel brake noise. And a brake fluid pressure of the remaining system is increased by a predetermined fluid pressure in accordance with the reduced pressure amount. Brake noise preventing device according to claim.