JPH0454325A - Brake for vehicle - Google Patents

Abstract

PURPOSE:To prevent brake noise phenomenon by detecting vibration of a friction member of a brake unit having a rotary member and the friction member by piezoelectric effect, and giving vibration to the friction member by an excitation means to damp the detected vibration. CONSTITUTION:A piston 14 and a caliper 13 are provided to press a disc 10 for a rotary member to rotate integrally with a wheel by an inner pad 11 and an outer pad 12. A vibration senser 15 laminated with a piezoelectric element 15a is inserted into a hole 13d of the caliper 13, and an excitation actuator 16 laminated with a piezoelectric element 16a is inserted into a hole 13e. The vibration senser 15 generates a voltage by the piezoelectric effect of the piezoelectric element 15a by vibration of the outer pad 12 and inputs it to a controller 17. and the outer pad 12 is vibrated by the excitation actuator 16 by a vibration frequency having an inverse phase. Vibration of the outer pad 12 is thus prevented, and brake noise phenomenon is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a braking device for a vehicle that applies braking force to wheels.

(Prior Art and Problems to be Solved by the Invention) A braking device for a vehicle in which a friction member is pressed by a pressing means against a rotating member that rotates integrally with the wheel to apply a braking force to the wheel by frictional force. For example, JP-A-56-1
It has been widely known as disclosed in Japanese Patent No. 0836.

In this type of vehicle braking device, the friction member vibrates during braking due to various causes, producing a harsh noise. A so-called brake squeal phenomenon may occur, and various countermeasures have been proposed to eliminate this phenomenon.

However, even up to the present time, no effective measures have been taken to completely eliminate the brake squeal phenomenon, and various research and development efforts are currently underway.

Therefore, the technical object of the present invention is to completely eliminate the above-mentioned brake squeal phenomenon in the vehicle braking device.

[Structure of the invention]

(Means for Solving the Problems) The measures taken to solve the above-mentioned technical problems include, in the vehicle braking device, a vibration detection means that detects vibrations of the friction member by the piezoelectric effect of a piezoelectric element; A vibrating means is provided for vibrating the friction member by an inverse piezoelectric effect of a piezoelectric element so that the vibration is attenuated in the friction member in response to the vibration detected by the vibration detection means.

In the vehicle braking device configured as described above, it is preferable that the vibration excitation means apply vibration to the friction member having a phase difference of 180° with respect to the vibration detected by the vibration detection means.

Furthermore, in the vehicle braking device, the piezoelectric element constituting the vibration detecting means and the piezoelectric element constituting the vibrating means may be used in common.

(Function) According to the above means, when the friction member vibrates during braking, the piezoelectric element constituting the vibration detection means generates a voltage due to its piezoelectric effect, and the vibration of the friction member is detected from the voltage. Ru. When vibration of the friction member is detected, the friction member is vibrated so as to attenuate the detected vibration by applying a voltage to a piezoelectric element constituting the vibration excitation means. This eliminates the brake squeal phenomenon in which a harsh noise is generated due to vibration of the friction member.

(Example) Hereinafter, an example of a vehicle braking device according to the present invention will be described based on the drawings.

FIG. 1 shows an example in which the present invention is applied to a disc brake for a vehicle. In FIG. 1, reference numeral 10 denotes a disk that rotates integrally with the wheel, and the disk IO corresponds to the rotating member according to the present invention. An inner pad 11 and an outer pad 12 are supported on both sides of the disk 10 so as to be able to pinch the disk 10 and to be slidable in the axial direction of the disk 10 on mountings (not shown).

A caliper 13 is disposed on a mounting (not shown) so as to be slidable in the axial direction of the disk 10 so as to straddle the outer periphery of the disk 10 . The caliper 13 includes a piston portion 13b containing a piston 14 that presses the inner pad 1 against the inner surface of the disk 10, and a reaction force of the pressing force of the piston 14 that causes the caliper 13 to slide toward the inside of the vehicle. It includes a reaction part 13b that presses the other side of the disk 10, and a bridge part 13C that connects the reaction part 13b and the piston part 13a.

The reaction portion 13b of the caliper 13 is provided with holes 13d and 13e in this embodiment. Hole 1
3d, a vibration sensor 5 formed by laminating a plurality of piezoelectric elements 15a has both ends connected to the bottom wall of the hole 13d and the outer pad 12.
It is inserted so that it is in contact with the back plate of. Also, hole 13
A vibrating actuator 16 similarly formed by stacking a plurality of piezoelectric elements 16a is fitted into the hole 13e so that both ends thereof come into contact with the bottom wall of the hole 13e and the back plate of the outer pad 12. The vibration sensor 15 and the vibration actuator 6 constitute vibration detection means and vibration excitation means according to the present invention, respectively.

The vibration sensor 15 is configured to generate a voltage corresponding to the vibration of the outer pad 12 through the piezoelectric effect of the piezoelectric element 15a, and is connected to the control device 17. As shown in the block diagram in FIG. 2, the control device 17 determines whether or not the outer pad 12 has a vibration based on the correspondence between the applied voltage from the vibration sensor 15 and the vibration of the outer pad 12, which is preset according to the characteristics of the piezoelectric element. an oscillation circuit 19 that generates a pulse voltage according to the vibration detected by the vibration detection circuit 18, and a pulse voltage generated by the oscillation circuit 19 and applied from the vibration sensor 15. A tuning circuit 20 that tunes the voltage to be tuned, and a tuning circuit 20 that excites by inverting the phase of the pulse voltage tuned by the tuning circuit 20 with respect to the phase of the frequency detected by the vibration detection circuit 19 (may be shifted by a predetermined time). The delay circuit 21 is provided to the actuator 17.

Further, the vibration actuator 16 is configured to vibrate at a vibration frequency corresponding to the pulse voltage due to the piezoelectric effect of the piezoelectric element 16a in response to a pulse voltage applied by the delay circuit 21, and vibrate the outer pad 12. In addition, in FIG. 1, 22 is a mask cylinder, and the mask cylinder 2
The hydraulic pressure in one of the two pressure chambers is applied to the piston 14.

Based on the above configuration, in this embodiment, the brake pedal 2
3 is depressed and hydraulic pressure is applied to the piston 14, the piston 14 presses the inner pad 11 against the disc 10, and the reaction force causes the caliper 13 to slide in the axial direction of the disc 10, and the reaction part 13b Outer pad 1
2 is pressed against the other side of the disc 10 to perform a braking action.

At this time, the vibration of the disc 10 and the disc 1 of both pads may be affected.
When the outer pad 12 vibrates due to uneven surface pressure relative to 0, the vibration sensor 15 activates the piezoelectric element 15 in response to the vibration.
A voltage is generated by the piezoelectric effect of a, and the voltage is input to the vibration detection circuit 18 of the control device 17. Vibration detection circuit 1
8 detects the vibration frequency of the outer pad 12 based on the input voltage, and inputs the signal to an oscillation circuit 19, which generates a pulse voltage according to the vibration frequency. After this pulse voltage is tuned by the tuning circuit 20 to the voltage applied from the vibration sensor 15, its phase is inverted by the delay circuit 21 with respect to the phase of the frequency detected by the vibration detection circuit 19, and the pulse voltage is applied to the vibration actuator 1.
6 is given. As a result, the vibration actuator 16
Due to the inverse piezoelectric effect of the piezoelectric element 16a, the outer pad 1
The outer pad 12 is vibrated with a vibration frequency having an opposite phase so as to attenuate the vibration frequency of the outer pad 12.
vibration is prevented.

As described above, in this embodiment, the vibration of the outer pad 2 during braking is transmitted to the vibration sensor 15 and the control device 17.
When detected, the outer pad 12 is vibrated by the vibrating actuator 16 at a vibration frequency with an opposite phase so as to cancel out this vibration, thereby preventing the outer pad 12 from vibrating and causing brake squeal due to this vibration. is prevented. Moreover, in this embodiment, since the vibration of the pad can be prevented, it is also possible to prevent the brake vibration transmitted to the brake pedal via the brake fluid due to the vibration of the pad.

3 to 6 show modified embodiments of the present invention,
In this embodiment, the same components as those in the above-described embodiment are given the same reference numerals, and the explanation thereof will be omitted, and the differences will be explained below.

As shown in FIG. 4, a hole 24a is formed in the surface of the torque receiver on the disk 100 rotation direction side of the mounting 24 that slidably supports both pads, and one end is always kept in the hole 24a. A vibrating piston 25 in contact with the outer pad 12 is slidably fitted in a liquid-tight manner. As a result, a liquid chamber 26 is formed within the hole 24a.

The piezoelectric piston mechanism 30 includes a body 31 having an inner hole;
A piston 32 is slidably fitted into the inner hole of the body 31 in a liquid-tight manner, and a plurality of piezoelectric elements are stacked and interposed in an air chamber 35 defined in the body 31 by the piston 32. It is composed of an element 33. Further, the liquid chamber 34 formed in the inner hole of the body 31 by the piston 32 is connected to the liquid chamber 2 formed in the mounting ring 24 via the piping 27.
6, and constitutes a closed space filled with hydraulic fluid.

Therefore, in this embodiment, when the disc 10 is pinched by both pads 1112 and a braking action is performed,
When the outer pad 12 vibrates, the vibrating piston 25 is vibrated, and the vibration of the vibrating piston 25 causes the liquid chamber 2 to vibrate.
6 and the liquid chamber 34, the piston 32 is vibrated. When the piston 32 vibrates, the piezoelectric element 33 is vibrated to generate a voltage due to the piezoelectric effect, and this voltage is transmitted to the control device 4.
Applied to 0. The magnitude of the voltage applied to the control device 40 is detected by a voltage detection circuit 41, and after this detected voltage is amplified by an amplifier circuit 42, its frequency is shifted in phase by 180 degrees by a delay circuit 43. And 1
Pulsed voltages with a phase shift of 80° are applied to the piezoelectric element 33 of the piezoelectric piston mechanism 30 via the drive circuit 44,
The vibration piston 25 is vibrated via the piston 32 to damp the vibration of the outer pad 12.

This prevents brake squeal and brake vibration from occurring due to pad vibration.

FIG. 6 shows a modification of the control device in the modified embodiment shown in FIG. Vibration detection is allowed by the vibration detection switch 52 according to the applied voltage from the
A switching circuit 57 switches signals having a phase shift of 180 degrees, and the piezoelectric element 33 is driven by this signal.

In FIG. 6, 53, 54, 55, and 56 are the oscillation circuit, tuning circuit, and delay circuit of the vibration detection circuit 1 shown in FIG. 2, respectively.

〔Effect of the invention〕

According to the present invention, when vibration of the pad during braking is detected by the vibration detecting means, the pad is vibrated by the vibrating means at a vibration frequency having an opposite phase so as to cancel out the vibration. The vibration of the brake pad is prevented, and the brake squeal phenomenon caused by this vibration is prevented, and the brake vibration transmitted to the brake pedal via the brake fluid due to the vibration of the pad can also be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a vehicle braking device according to the present invention, FIG. 2 is a block diagram of the control device in FIG. 1, and FIG. 3 is a sectional view showing a modified embodiment of the present invention. , FIG. 4 is a sectional view showing a part of the vibration excitation means in FIG. 3, FIG. 5 is a block diagram of the control device in FIG. 3, and FIG.
It is a block diagram which shows the modification of the control apparatus in the Example shown in a figure. 10... Disc (rotating member), 11.12... Pad (friction member), 13... Caliper (pressing means),
14... Piston (pressing means) 15... Vibration sensor (vibration detection means), 15a... Piezoelectric element (vibration detection means), 16... Vibration actuator (vibration means), 1
6a... Piezoelectric element, 17... Control device, (vibration detection means, vibration excitation means), 25... Vibration screw (vibration detection means, vibration excitation means), 30... Piezoelectric piston (vibration detection means) 40.50...control device (vibration detection means, vibration means).

Claims (3)

[Claims] (1) In a vehicle braking device that brakes a rotating member that rotates integrally with a wheel by pressing a friction member against the rotating member using a pressing means, the vibration of the friction member is detected by the piezoelectric effect of a piezoelectric element. A vibration detecting means, and a vibrating means for vibrating the friction member by an inverse piezoelectric effect of a piezoelectric element so that the vibration is attenuated in the friction member according to the vibration detected by the vibration detecting means. Characteristic vehicle braking device. (2) The vehicle braking device according to claim 1, wherein the vibration excitation means applies vibration to the friction member having a phase difference of 180 degrees with respect to the vibration detected by the vibration detection means. (3) The vehicle braking device according to any one of claims (1) and (2), wherein a piezoelectric element constituting the vibration detecting means and a piezoelectric element constituting the vibrating means are shared.