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US-12618445-B2 - Method and device for determining the wear of a brake

US12618445B2US 12618445 B2US12618445 B2US 12618445B2US-12618445-B2

Abstract

The disclosure relates to a method for determining the wear of a brake of a motor vehicle having a brake piston, an actuator, a first brake lining, a second brake lining, a friction partner and a mounting, where the brake piston is held on a spindle of the brake and can be moved axially along the spindle between the actuator and the friction partner.

Inventors

  • Andreas Marx
  • Nicholas Alford

Assignees

  • ZF ACTIVE SAFETY GMBH

Dates

Publication Date
20260505
Application Date
20230801
Priority Date
20220812

Claims (10)

  1. 1 . A method for determining a wear of a brake of a motor vehicle having a brake piston, an actuator, a first brake lining, a second brake lining, a friction partner and a mounting, wherein the brake piston is held on a spindle of the brake and can be moved axially along the spindle between the actuator and the friction partner, the method comprising: removing the first brake lining and the second brake lining from the brake; moving the brake piston in the direction of the actuator until the brake piston comes into contact with the actuator; determining a minimum spacing S0 of the brake piston from the actuator in a state in which the actuator is acted upon by the brake piston with the first brake lining and the second brake lining removed; moving the brake piston in the direction of the friction partner until the friction partner is in contact with the brake piston and the mounting; determining a maximum spacing S3 of the brake piston from the actuator in a further state in which the friction partner is acted upon by the brake piston and the mounting with the first brake lining and the second brake lining removed; and establishing a thickness of the friction partner from the maximum spacing S3 and the minimum spacing S0.
  2. 2 . The method according to claim 1 , moreover comprising removal of the first brake lining and the second brake lining from the brake before the brake piston moves in the direction of the friction partner.
  3. 3 . The method according to claim 1 , moreover comprising moving the brake piston in order to bring the first brake lining and the second brake lining each into contact with the friction partner; determining a first average spacing S1 of the brake piston from the actuator in the state in which the brake piston is acted upon by the brake linings; and establishing a thickness of the first brake lining and the second brake lining from the first average spacing S1 and the minimum spacing S0.
  4. 4 . The method according to claim 3 , moreover comprising: moving the brake piston again in order to bring the first brake lining and the second brake lining in each case into contact with the friction partner; determining a second average spacing S2 of the brake piston from the actuator in the state in which the brake piston is acted upon again by the brake linings; determining the wear of the first brake lining and the second brake lining based on the minimum spacing S0, the first average spacing S1, and the second average spacing S2.
  5. 5 . The method according to claim 4 , wherein the steps of moving again, determining a second average spacing S2, and determining the wear are performed when the motor vehicle is stationary.
  6. 6 . The method according to claim 4 , moreover comprising providing a warning signal when the thickness of the first brake lining and the second brake lining falls below a predetermined threshold value.
  7. 7 . The method according to claim 4 , moreover comprising setting a predetermined spacing between the first brake lining and the friction partner, preferably after the thickness of the first brake lining and the second brake lining has been established.
  8. 8 . A device for determining a wear of a brake of a motor vehicle having a brake piston, an actuator, a first brake lining, a second brake lining, a friction partner and a mounting, wherein the brake piston is held on a spindle of the brake and can be moved axially along the spindle between the actuator and the friction partner, the device comprising: a sensor which is adapted to determine a minimum spacing S0, a maximum spacing S3, a first average spacing S1 and a second average spacing S2, wherein the actuator is acted upon by the brake piston at the minimum spacing S0 with the first brake lining and the second brake lining removed, wherein the friction partner is acted upon by the brake piston and the mounting at the maximum spacing S3 with the first brake lining and the second brake lining removed, wherein the brake piston is acted upon by the brake linings at the first average spacing S1 and the second average spacing S2 with the first brake lining and the second brake lining installed, wherein the device is adapted to establish a thickness of the friction partner from the maximum spacing S3 and the minimum spacing S0, and to determine the wear of the first brake lining and the second brake lining based on the minimum spacing S0, the first average spacing S1, and the second average spacing S2.
  9. 9 . The device according to claim 8 , wherein the actuator comprises an electric motor with a transmission and a control unit, wherein the control unit is adapted to determine the minimum spacing S0, the first average spacing S1, the second average spacing S2 and the maximum spacing S3 and optionally communicate them to vehicle electronics.
  10. 10 . A motor vehicle with a plurality of brakes, wherein each of the plurality of brakes is provided with the device according to claim 8 .

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to German Priority Application No. 102022120404.9, filed Aug. 12, 2022, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD The disclosure relates to a method and a device for determining the wear of a brake, and to a motor vehicle with a plurality of brakes, wherein each of the plurality of brakes is provided with the device according to the disclosure. BACKGROUND It is known to subject the brake linings of conventional electrohydraulic brake systems of motor vehicles to a check in terms of the wear. The brake linings are thus provided with a plurality of electrical contacts embedded in different layers of the respective brake lining. The electrical contacts are gradually removed or destroyed with progressive abrasion of the brake linings. The driver of the motor vehicle is informed about the degree of wear of the brake disc by the absence of electrical signals, communicated to the bus system of the motor vehicle and detected, which occurs in this case. The generic document DE 10 2014 212 594 A1 relates to a method for identifying the wear of a brake system. First, an assembled brake lining and an adjustment mechanism for tensioning the brake linings against a friction partner are provided. The brake lining is moved towards a fixed point, its displaced position being established. The brake lining is then moved towards a measurement point of the associated friction partner at which the brake lining rests directly on the friction partner or has reached an end point. After the displaced position of the measurement point has been established, a current degree of brake lining wear is calculated which is derived from the established displaced positions of the fixed point and the measurement point. A brake system is furthermore provided which is designed to identify the wear of an assembled brake lining using the method. However, the method known from the prior art has the disadvantage that only the wear of the brake lining is established and other components of the brake are not taken into account. This can cause problems in accurately detecting the wear and in evenly decelerating the vehicle because the motor vehicle becomes destabilized and possibly out of control during a braking procedure, such as in an emergency braking procedure. SUMMARY The disclosure relates to a method for determining the wear of a brake of a motor vehicle having a brake piston, an actuator, a first brake lining, a second brake lining, a friction partner, and a mounting, wherein the brake piston is held on a spindle of the brake and can be moved axially along the spindle between the actuator and the friction partner, the method comprising: moving the brake piston in the direction of the actuator until the brake piston is in contact with the actuator; determining a minimum spacing S0 of the brake piston from the actuator in the state in which the actuator is acted upon by the brake piston; moving the brake piston in the direction of the friction partner until the friction partner is in contact with the brake piston and the mounting; determining a maximum spacing S3 of the brake piston from the actuator in the state in which the friction partner is acted upon by the brake piston and the mounting; and establishing a thickness of the friction partner from the maximum spacing S3 and the minimum spacing S0. The disclosure moreover relates to a device for determining the wear of a brake of a motor vehicle having a brake piston, an actuator, a first brake lining, a second brake lining, a friction partner, and a mounting, wherein the brake piston is held on a spindle of the brake and can be moved along the spindle between the actuator and the friction partner, the device comprising: a sensor which is adapted to determine a minimum spacing S0, a maximum spacing S3, a first average spacing S1 and a second average spacing S2, wherein the actuator is acted upon by the brake piston at the minimum spacing S0, wherein the friction partner is acted upon by the brake piston and the mounting at the maximum spacing S3, wherein the brake piston is acted upon by the brake linings at the first average spacing S1 and the second average spacing S2, wherein the device is adapted to establish a thickness of the friction partner from the maximum spacing S3 and the minimum spacing S0, and to determine the wear of the first brake lining and the second brake lining based on the minimum spacing S0, the first average spacing S1, and the second average spacing S2. The disclosure furthermore relates to a motor vehicle with a plurality of brakes, wherein each of the plurality of brakes is provided with the device according to the disclosure. The friction partner can be a brake disc or brake drum. For instance, the friction partner can be a brake disc of a disc brake, for example a floating-caliper brake, or a brake drum of a drum brake. The friction partner can