Disk Brake Provided With an Improved Device for Measuring the Normal Applied Force

• US 20090133971A1
• Filed: 07/11/2006
• Published: 05/28/2009
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Baier-Welt, Christian
• Granted Patent: US 8,146,715 B2
• Time in Patent Office: Days
• US Class Current: 188/1.11E
• CPC Class Codes: F16D 2055/0016 Brake calipers
• CPC Class Codes: F16D 2066/005 Force, torque, stress or strain
• CPC Class Codes: F16D 66/00 Arrangements for monitoring working conditions, e.g. wear, temperature

Abstract

A disk brake, in particular for a motor vehicle, is provided. The disk includes a rotatable brake disk, a brake caliper covering the brake disk, an actuator for applying an actuation force and a friction lining applicable to the brake disk by means of the actuation force, and a device for measuring the actual braking force. In order to obtain the more reliable and accurate actual braking force measurement, the device for measuring the actual braking force uses the elastic enlargement of the brake caliper in the form of a measuring parameter and comprises an element having a first end secured to the brake caliper and a second free end, wherein a gap is formed in the extension direction between the brake caliper and the element. The device for measuring the actual braking force produces a signal according to the actual measure gap width.

Claims

1-18. -18. (canceled)

19. A disk brake for motor vehicles, comprising:

a rotatable brake disk;

a brake caliper covering the brake disk;

an actuator for applying an actuation force and friction linings applicable to the brake disk via the actuation force; and

a device for measuring the actual braking force, the device uses the elastic expansion of the brake caliper as a measured variable, and the device comprises an element having a first end secured to the brake caliper and a second free end,

wherein a gap is formed between the brake caliper and the element along its extension from the first to the second end, and

wherein the device measures the actual width of said gap, and emits a signal as a function of the actually measured gap width.

20. The disk brake as claimed in claim 19, wherein the element is formed in one piece with the brake caliper.

21. The disk brake as claimed in claim 19, wherein the device includes a sensor device that measures the actual gap width in the area of the free end of the element.

22. The disk brake as claimed in claim 21, wherein the sensor device operates according to an electromagnetic measurement principle.

23. The disk brake as claimed in claim 22, wherein the sensor device operates according to the inductance measurement principle.

24. The disk brake as claimed in claim 23, wherein the sensor device comprises a coil having a moving ferromagnetic core.

25. The disk brake as claimed in claim 23, wherein the sensor device operates according to the eddy-current principle.

26. The disk brake as claimed in claim 21, wherein the sensor device operates according to the reflex light barrier principle.

27. The disk brake as claimed in claim 21, wherein the sensor device measures the ovality and/or size and/or position of an optical light cone projecting from one side of the gap to the other side thereof.

28. The disk brake as claimed in claim 19, wherein the device for measuring the actual braking force determines a starting gap width in order to carry out a zero-point calibration, and in that the starting gap width is measured with the friction linings in the released state.

29. The disk brake as claimed in claim 28, wherein during a prolonged braking the friction linings are again shifted to the released state and a further zero-point calibration then carried out by measuring the starting gap width in order to compensate for any thermally induced zero-point drift of the sensor device.

30. The disk brake as claimed in claim 28, wherein the device for measuring the actual braking force records the temperature of the brake caliper at one or more points, determines on the basis of this temperature information the thermally induced expansion of the brake caliper and then corrects accordingly an actually measured value of the gap width, which due to the determined expansion of the brake caliper is affected by a zero-point drift attributable to thermal influences.

31. The disk brake as claimed in claim 28, wherein the device for measuring the actual braking force calculates the temperature of the brake caliper based on an energy and temperature model of the brake caliper, determines with the aid of the calculated brake caliper temperature the thermally induced expansion of the brake caliper and then corrects accordingly an actually measured value of the gap width, which due to the determined expansion of the brake caliper is affected by a zero-point drift attributable to thermal influences.

32. The disk brake as claimed in claim 30, wherein the thermally induced expansion of the brake caliper is determined computationally on the basis of the material-dependent thermal expansion coefficients.

33. The disk brake as claimed in claim 30, wherein the thermally induced expansion of the brake caliper is determined with the aid of a table which contains values for the expansion of the brake caliper as a function of the temperature.

34. The disk brake as claimed in claim 21, wherein the actual temperature of a sensor of the sensor device is measured, and a thermally induced deviation of the sensor from linearity is compensated for by means of an individual temperature coefficient.

35. The disk brake as claimed in claim 19, wherein the device for measuring the actual braking force is calibrated by means of a table of measured values containing brake-caliper-expansion values recorded as a function of the braking force by a calibration reference sensor.

36. The disk brake as claimed in claim 19, wherein the actuator is an electromechanical actuator