DE102007039614A1 - Electric brake with noise reducing measures - Google Patents

Abstract

The invention relates to a method for driving the actuator (4) of a brake (1), in particular an electromotive brake. The generation of brake noise can be significantly reduced if the actuator (4) of the brake is controlled such that the macroscopic adjusting movement (13) of the actuator (4) is superimposed on a second movement (14), which leads to a reduction of brake noise.

Description

The The invention relates to a method for driving the actuator of a Brake according to the preamble of the claim 1, and a control device according to the preamble of patent claim 11.

Known Vehicle brakes, such. B. disc brakes, can during Brakes develop strong sounds from the occupants the vehicle are distracting. In the professional world one speaks of "Muhen", "chirping", "squeaking" until to "howling" and "creaking" to the brake noise to mark. These noises are created in particular due to vibrations of caliper, brake pads or other Brake or vehicle components that resonate when braking become.

to Avoiding brake noise it is known the caliper detuned by local mass accumulations. To this Purpose, the caliper is formed thicker at certain points and has z. For example, a bead on, while in other places is formed thinner. In addition, it is known, so-called provide phase-shifting plates between the brake pad and brake caliper to To prevent vibrations of the saddle. Furthermore Active systems are also known that work in conjunction with noise sensors create a "counter noise", the brake noise partially or completely extinguished.

Other known approaches, for. In DE 199 31 081 , Overlay the braking force high-frequency vibrations, preferably in the ultrasonic range with actuators, which are arranged between the brake pads and their back plates.

The Known measures usually require the use additional components and are relatively expensive too realize.

It is therefore the object of the present invention, the noise to prevent braking with simple means.

Solved This object is achieved according to the invention by the specified in claim 1, 11 and 12 features. Further embodiments The inventions are the subject of dependent claims.

One essential aspect of the invention is the actuator of the Brake (which serves to tighten or release the brake) so to control that the actuator in addition to a macroscopic adjustment movement performs a second, microscopic motion that the Stellbewegung is superimposed. The actuators of the brake are preferably controlled by means of a control signal, the a basic signal, such as. B. a PWM signal (PWM: pulse width modulation) having a second signal superimposed thereto the microscopic movement of the actuator leads. This has the significant advantage that the emergence of brake noise alone through the use of existing resources, without the use of additional resources mechanical components or actuators can be prevented.

in the In the case of a PWM control signal, the PWM signal is preferably on superimposed second signal, which z. B. the duty cycle or the frequency of the PWM signal varies.

According to one preferred embodiment of the invention is the amplitude the superimposed second movement much smaller than the amplitude of the macroscopic adjusting movement, which is the application or releasing the brake is used. The frequency of the superimposed second movement is preferably substantially higher than her the frequency of the actuating movement of the actuator in a control the brake.

Of the temporal course of the superimposed second movement can z. B. amplitude, frequency, phase or otherwise modulated be.

Of the temporal course of the superimposed second movement can also basically sinusoidal, rectangular, triangular or be polygonal or may have any other shape.

The superimposed second movement can be, for example, a harmonic movement. According to a preferred embodiment however, the superimposed movement is not harmonic and varies, for example, in frequency and / or amplitude and / or shape.

Of the temporal course of the superimposed second movement can for example, follow a stochastic pattern.

Of the temporal course of the superimposed second movement is furthermore preferably a (continuous or unsteady) function the application force of the brake. As a result, especially during heavy braking used a higher amplitude overlay become.

to Noise reduction can either be a pure control or regulation. In case of a Control is a controller provided, for example, deposited in a control unit and one or more noise sensors for measurement the brake noise.

The actuator is preferred wise to an electric motor.

The Invention will be described below with reference to the accompanying drawings exemplified in more detail. Show it:

1 a schematic side view of a wedge brake;

2a the time course of an actuating movement of the brake of 1 ;

2 B the time course of an actuating movement of the brake of 1 with a superimposed second movement;

3 a PWM signal for controlling the electric motor of the wedge brake 1 ,

1 shows a side view of an electromechanical wedge brake 1 , which is realized here as a disc brake. The brake 1 includes an actuator 4 that with a movable wedge plate 3 is connected and operated in the direction of arrow C. The wedge plate 3 has on its front side (in the picture below) a lining carrier 7 on which a brake pad 8th is attached. At the back there are several wedge surfaces 11 that run in a zigzag shape.

A fixed wedge plate 2 that are on the caliper 16 supports, serves as an abutment of the brake, which takes the braking business. The fixed wedge plate 2 also has zigzag-shaped wedge surfaces at its front 11 , Between the two wedge plates 2 . 3 There are several rolling elements 10 , which essentially serve to improve the sliding friction.

To the brake 1 to tension or release, the movable wedge plate 3 from the actuator 4 , such as an electric motor, driven in the actuating direction C (to the left or right). The rolling elements migrate 10 along the wedge surfaces 11 upwards or downwards, resulting in the movable wedge plate 3 moved either in the direction of arrow A or in the direction of arrow B. The active wedge plate 3 with the brake pad can thus on the brake disc 9 be moved to or from this.

The actuator 4 is with a control unit 5 via a control line 6 connected and is driven by the latter according to the braking request. The control unit 5 generates a PWM signal here 15 with a given duty cycle, as in 3 is shown by way of example.

2a shows the time course of a positioning movement 13 as seen from the actuator 4 can be executed. The adjusting movement 13 is exemplified linearly here. The brake is in operation at an operating point AP (see 2 B ), which is circulated in the context of a force or braking torque control (see arrows).

2 B shows the time course of an actuating movement of the actuator 4 with a superimposed microscopic motion 14 , which serves to avoid brake noises. As can be seen, the amplitude of the superimposed second movement 14 much smaller than the amplitude of the actuating movement of the active wedge plate 3 at a regulation. The frequency of the superimposed second movement 14 is higher than the frequency of the control.

The superimposed movement 14 is shown here as a sinusoidal movement. The temporal course of the superimposed movement can also be rectangular, triangular or polygonal or have any other shape. The temporal course of the superimposed second movement 14 may also be amplitude, frequency or phase modulated or modulated in some other way.

Of the time course of the superimposed movement is preferred a function of the brake application force. The higher the Clamping force, the higher, for example, the amplitude to be the superimposed movement.

3 shows a typical PWM signal 15 for controlling the actuator 4 , The PWM basic signal 15 For example, a second signal may be superimposed on the duty cycle of the signal 15 varies (see arrow 17 ) or the frequency of the signal 15 modulated (see arrow 18 ).

1

brake

2

fixed wedge plate

3

portable wedge plate

4

actuator

5

control unit

6

control line

7

Brake lining carrier

8th

brake lining

9

brake disc

10

rolling elements

11

wedge surface

12

sound sensor

13

actuating movement

14

superimposed Move

15

PWM signal

16

caliper

17

modification the duty cycle

18

modification the frequency

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19931081 [0004]

Claims (13)

Method for actuating the actuator ( 4 ) a brake ( 1 ), in particular an electromotive vehicle brake, characterized in that the actuator ( 4 ) is controlled in such a way that, in addition to a macroscopic positioning movement ( 13 ) a microscopic second movement ( 14 ) performs the adjusting movement ( 13 ) is superimposed and leads to a reduction of the brake noise. Method according to claim 1, characterized in that the amplitude of the superimposed second movement ( 14 ) is substantially smaller than the actuating movement of the actuator ( 4 ) during braking. Method according to claim 1 or 2, characterized in that the superimposed second movement ( 14 ) is a periodic movement. A method according to claim 3, characterized in that the frequency of the periodic movement is substantially greater than the frequency of the actuator ( 4 ) executed adjusting movement. Method according to one of the preceding claims, characterized in that the time profile of the superimposed second movement ( 14 ) is amplitude, frequency, phase or otherwise modulated. Method according to one of the preceding claims, characterized in that the time profile of the superimposed second movement ( 14 ) is sinusoidal, rectangular, triangular or polygonal or may have any other shape. Method according to one of the preceding claims, characterized in that the time profile of the superimposed second movement ( 14 ) is harmonious. Method according to one of claims 1-6, characterized in that the time profile of the superimposed second movement ( 14 ) is not harmonic and varies in frequency and / or amplitude and / or shape. Method according to one of the preceding claims, characterized in that the time profile of the superimposed second movement ( 14 ) follows a stochastic pattern. Method according to one of the preceding claims, characterized in that the time profile of the superimposed second movement ( 14 ) a function of the application force of the brake ( 1 ). Control device, comprising means for actuating an actuator ( 4 ) a brake ( 1 ) by means of a control signal ( 15 ), due to which the actuator ( 4 ) in addition to a macroscopic adjusting movement a microscopic, second movement ( 14 ) performs the adjusting movement ( 13 ) is superimposed and leads to a reduction of the brake noise Vehicle brake with at least one actuator ( 4 ) and a brake control ( 5 ), which controls the actuator according to one of the preceding claims 1 to 10. Vehicle brake according to claim 12, characterized in that that the actuator is an electric motor.