METHOD FOR ADJUSTING THE CLEARANCE OF AN ELECTROMECHANICAL BRAKE, BRAKE, AND CONTROL DEVICE

Abstract

A method for adjusting the clearance of an electromechanical brake, in particular of a utility vehicle brake, involves the following steps: activating a clearance test cycle for the brake, applying at least one brake lining of the brake in the direction of a brake disc and determining a contact position in which the brake lining enters into contact with the brake disc when application occurs, determining the clearance as well the degree of wear of the lining on the basis of the determined contact position, calculating the clearance which is necessary for the brake and a necessary contact position of the brake lining and brake disc in accordance with the degree of wear of the lining using predefined parameters. The method is performed by a suitable brake and a control device.

Claims

1. A method (200) for adjusting a clearance (L) of an electromechanical brake (100) of a vehicle, comprising the steps of: activating (202) a clearance test cycle for the brake (100); applying (204) a brake pad (103) of the brake (100) toward a brake disc (105) and determining (204a) a contact position (K.sub.ist), at which the brake pad (103) comes into contact with the brake disc (105) during application (204); determining (206) the clearance (L.sub.ist) and a degree of pad wear (V.sub.B) based on the basis of the determined contact position (K.sub.ist); calculating (208) a required clearance (L.sub.Soll) for the brake (100) and a required contact position (K.sub.Soll) of the brake pad (103) and brake disc (105) as a function of the degree of pad wear (V.sub.B) using predefined parameters (P).

2. The method (200) as claimed in claim 1, further comprising the step of: comparing (210) the determined contact position (K.sub.ist) with the required contact position (K.sub.Soll) or comparing the determined clearance (L.sub.ist) with the required clearance (L.sub.Soll), and upon determining that the determined contact position (K.sub.ist) deviates from the required contact position (K.sub.Soll) or that the determined clearance (L.sub.ist) deviates from the required clearance (L.sub.Soll) by less than a tolerance value (T), generating a braking readiness signal (212).

3. The method (200) as claimed in claim 2, wherein, upon determining that the determined contact position (K.sub.ist) deviates from the required contact position (K.sub.Soll) or that the determined clearance (L.sub.ist) deviates from the required clearance (L.sub.Soll) by more than the tolerance value (T), a required clearance adjustment distance (216) is calculated.

4. The method (200) as claimed in claim 3, comprising the further steps of: adjusting (218) the clearance (L.sub.ist) according to the calculated required clearance adjustment distance (216); reactivating the clearance test cycle (202) for the brake (100).

5. The method (200) as claimed in claim 4, wherein, upon determining that no contact position (K.sub.ist) or no clearance (L.sub.ist) can be found for which the determined contact position (K.sub.ist) deviates from the required contact position (K.sub.soll) or for which the determined clearance (L.sub.ist) deviates from the required clearance (L.sub.soll) by less than a tolerance value (T), an error signal (220) is generated.

6. The method (200) as claimed in claim 1, wherein the predefined parameters (P) comprise at least one of the following: a brake characteristic curve; and a stiffness characteristic map, in which state-dependent stiffness values are stored.

7. The method (200) as claimed in claim 4, wherein the adjustment (218) of the clearance (L) is carried out by an electric clearance adjustment device (20).

8. The method (200) as claimed in in claim 7, wherein the calculation (216) of the required clearance adjustment distance (218) comprises determining operating parameters for the electric clearance adjustment device (20).

9. The method (200) as claimed in claim 1, wherein the activation (202) of the clearance test cycle takes place each time when the vehicle is put into operation.

10. The method as claimed in claim 1, wherein the method (200) is carried out for each of a plurality of brakes (1102, 1202, 1302, 1402) present on the vehicle.

11. The method (1000) as claimed in claim 1, wherein the clearance test cycle is performed only for fewer than all electromechanical brakes (1102, 1202, 1302, 1402) present on the vehicle.

12. A control device (8) for determining a clearance (L) of an electromechanical brake (100), comprising: a first interface (10) for a signal-conducting connection (6) of the control device (8) to a brake actuator (2); a second interface (12) for a signal-conducting connection (18) of the control device (8) to an electric clearance adjustment device (20); a data memory (14) and a processor (16), wherein the control device (8) is configured to activate a clearance test cycle for the brake (100); to cause an application (204) of at least one brake pad (103) of the brake (100) toward a brake disc (105) via the brake actuator (2) and to determine a contact position (K.sub.ist), at which the brake pad (103) comes into contact with the brake disc (105) during application (204); to determine the clearance (L.sub.ist) and a degree of pad wear (V.sub.B) based on the determined contact position (K.sub.ist), and to calculate a required clearance (L.sub.Soll) for the brake (100) and a required contact position (K.sub.Soll) of the brake pad (103) and brake disc (105) as a function of the degree of pad wear (V.sub.B) using predefined parameters (P).

13. The control device (8) as claimed in claim 12, wherein the control device (8) is configured to compare the determined contact position (K.sub.ist) with the required contact position (K.sub.Soll) or the determined clearance (L.sub.ist) with the required clearance (L.sub.Soll), upon determining that the determined contact position (K.sub.ist) deviates from the required contact position (K.sub.Soll) or that the determined clearance (L.sub.ist) deviates from the required clearance (L.sub.Soll) by less than a tolerance value (T), to generate a braking readiness signal (212), and upon determining that the determined contact position (K.sub.ist) deviates from the required contact position (K.sub.Soll) or that the determined clearance (L.sub.ist) deviates from the required clearance (L.sub.soll) by more than a tolerance value (T), to calculate a required clearance adjustment distance (216).

14. The control device (8) as claimed in claim 13, wherein the control device (8) is configured to adjust the clearance (L) according to the calculated required clearance adjustment distance (216), and to reactivate the clearance test cycle (202) for the brake (100).

15. The control device (8) as claimed in claim 13, wherein the control device (8) is configured, upon determining that no contact position (K.sub.ist) or no clearance (L.sub.ist) can be found for which the determined contact position (K.sub.ist) deviates from the required contact position (K.sub.soll) or for which the determined clearance (L.sub.ist) deviates from the required clearance (L.sub.soll) by less than a tolerance value (T), to generate an error signal (220).

16. An electromechanical brake (100), having a brake disc (105), at least one brake pad (103) accommodated in a brake caliper (107), an electromechanical brake actuator (2) for applying the at least one brake pad (103) toward the brake disc (105), an electric clearance adjustment device (20) for adjusting a clearance (L) between the brake disc (105) and the brake pad (103), and a control device (8) as claimed in claim 12.

17. A non-volatile computer memory storing instructions causing a control device to perform the method (200, 1000) as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In the drawings,

[0044] FIG. 1 shows a first exemplary embodiment of an electromechanical brake according to the invention with a control device for adjusting the clearance in a perspective view;

[0045] FIG. 2 shows a block diagram of a method for adjusting a clearance of an electromechanical brake; and

[0046] FIG. 3 shows a block diagram of a method for adjusting a clearance of electromechanical brakes of a vehicle.

DETAILED DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 shows a vehicle system 10000 having an electromechanical brake 100. The electromechanical brake 100 has a brake carrier 111 and a brake caliper 107. Brake pads 103 are guided and mounted on the brake carrier 111. By means of an electromechanical brake actuator 2, the brake pads 103 can be moved in the direction of a receiving space 105 for a brake disc (not shown) and can be applied to such a disc. The brake pads 103 are held in position by hold-down brackets 109 and hold-down springs 101. After removal of the hold-down bracket 109 and the hold-down springs 101, the brake pads 103 can be removed from the brake carrier 111 and can be replaced. The brake carrier 111 also has a pad retention plate 102 for laterally guiding the brake pads 103.

[0048] If the electromechanical brake 100 is in a non-actuated state, that is to say if no application force is applied to the brake pads 103 by the brake actuator 2, there is a clearance L between the brake pad 103 and the brake disc 105. The position at which at least one brake pad 103 comes into contact with the brake disc 105 is referred to as the contact position K. The brake 100 is applied by the application of an actuating force by the brake actuator 2 to an interface for an application mechanism 3, which in turn brings about application of the brake pads 103 in the direction of the brake disc 105.

[0049] The brake actuator 2 receives an actuator signal 22 for the actuation of the brake actuator 2. The brake actuator 2 is furthermore connected via a signal-conducting connection 6 to an interface 10 of a control device 8. The control device 8 determines with the actuator 2 a contact position K, in which the brake pads 103 come into contact with the brake disc 105. The control device 8 also has a data memory 14 and a processor 16. In addition, the control device 8 has a second interface 12, which is connected by means of a signal-conducting connection 18 to a clearance adjustment device 20, which is preferably configured as a stepping motor 20. The electric clearance adjustment device 20 is integrated into a wear sensor 4. The signal-conducting connections 6, 18 can be configured both as wired connections and as wireless connections.

[0050] A method 200 for adjusting a clearance of an electromechanical brake 100 according to FIG. 1 is illustrated in FIG. 2 using a block diagram. According to step 222, the method 200 is started by activating a vehicle ignition. With the activation of the vehicle ignition in method step 222, a clearance test cycle is activated in step 202. As part of this clearance test cycle, the brake actuator 2 applies the at least one brake pad 103 of the brake 100 in the direction of a brake disc 105 in accordance with step 204.

[0051] In step 204a, a contact position K.sub.ist is determined, at which the brake pad 103 comes into contact with the brake disc 105 during application. From the contact position K.sub.ist, the clearance L.sub.ist and a degree of pad wear V.sub.B are determined in accordance with step 206.

[0052] Furthermore, according to step 208, a clearance L.sub.soll required for the brake 100 and a required contact position K.sub.soll are calculated as a function of the degree of pad wear V.sub.B determined, wherein predefined parameters P are used according to step 208. According to step 210, the determined contact position K.sub.ist is compared with the required contact position K.sub.soll and the determined clearance L.sub.ist is compared with the required clearance L.sub.soll. In the case where the determined contact position K.sub.ist deviates from the required contact position K.sub.soll and/or the determined clearance L.sub.ist deviates from the required clearance L.sub.soll by less than a tolerance value T, a braking readiness signal 212 is generated.

[0053] In the case where the determined contact position K.sub.ist deviates from the required position K.sub.soll and/or the determined clearance L.sub.ist deviates from the required clearance L.sub.soll by more than the tolerance value T, a required clearance adjustment distance is calculated 216.

[0054] According to step 218, the clearance L.sub.ist is adjusted according to the calculated required clearance adjustment distance 216 and the clearance test cycle 202 is reactivated for the brake 100.

[0055] In the case where no contact position K.sub.ist or no clearance L.sub.ist can be found for which the determined contact position K.sub.ist deviates from the required contact position K.sub.soll and/or the determined clearance L.sub.ist deviates from the required clearance L.sub.soll by less than a tolerance value T, an error signal is generated according to step 220. The error signal according to step 220 can be output after a determinable number of unsuccessful cycle runs or on the basis of further parameters, for instance.

[0056] The calculation 216 of the required clearance adjustment distance 218 may furthermore comprise the determination of operating parameters for the electric clearance adjustment device 20, e.g. the specification of an adjustment step number or adjustment position for the electric drive (electric motor) of an electric clearance adjustment device 20.

[0057] FIG. 3 shows a method 1000 for adjusting a clearance L of electromechanical brakes 1102, 1202, 1302, 1402 of a vehicle 2000. Each of the brakes 1102, 1202, 1302, 1402 undergoes a method 200 for adjusting a clearance L of each electromechanical brake 1102, 1202, 1302, 1402.

[0058] According to step 1002, this involves coordination of the activation of the clearance test cycles of the brakes 1102, 1202, 1302, 1402. This coordination is preferably configured in such a way that only one of the brakes 1102, 1202, 1302, 1402 in each case undergoes the method 200 for adjusting a clearance of a brake. However, depending on the vehicle type, the operating mode, and other environmental conditions, it may furthermore be advantageous that two of the electromechanical brakes 1102, 1202, 1302, 1402, or even three of the relevant brakes 1102, 1202, 1302, 1402, respectively, simultaneously undergo the method 200 for adjusting a clearance.