ADAPTING A BRAKE CLEARANCE TO A TRAFFIC SITUATION

Abstract

The disclosure relates to a method for adapting a braking behaviour of a brake of a motor vehicle to a traffic situation, including: (i) adjusting a clearance of the brake to a value L.sub.K; (ii) determining the traffic situation; and (iii) adjusting the clearance to a value L.sub.A based on the determined traffic situation, wherein 0<L.sub.A<L.sub.K is satisfied.

Claims

1. A method for adapting the braking behaviour of a brake of a motor vehicle to a traffic situation, including: adjusting a clearance of the brake to a value L.sub.K; determining the traffic situation; and adjusting the clearance to a value L.sub.A based on the determined traffic situation, where 0<L.sub.A<L.sub.K is satisfied.

2. The method according to claim 1, wherein the adjustment of the clearance to a value L.sub.K is carried out when the motor vehicle is at a standstill, wherein the brake includes a brake lining with a contact surface and a friction surface, wherein adjusting the clearance to a value L.sub.K involves contacting the contact surface with the friction surface and adjusting the value L.sub.K between the contact surface and the friction surface.

3. The method according to claim 1, wherein the clearance is readjusted each time the motor vehicle is at a standstill.

4. The method according to claim 1, including determining a changed traffic situation; and adjusting the clearance to a value L.sub.B, where 0<L.sub.BL.sub.K is satisfied with L.sub.BL.sub.A.

5. The method according to claim 1, wherein the traffic situation includes a driving situation and/or a driver situation.

6. The method according to claim 1, including determining a changed traffic situation; and adjusting the clearance to a value L.sub.B, where 0<L.sub.B<L.sub.A is satisfied, wherein the traffic situation involves detection of a reduction in pressure exerted on an accelerator pedal of the motor vehicle, and the changed traffic situation involves detecting pressure exerted by touching or operating a brake pedal of the motor vehicle.

7. The method according to claim 1, wherein the brake is an electromechanical brake, wherein the motor vehicle has multiple brakes, wherein the clearance of each of the multiple brakes is adjusted individually or axle-by-axle.

8. The method according to claim 1, including the use of a control unit, of a driver assistance system to provide a first control signal for adjusting the clearance and a second control signal for adapting the clearance to the brake.

9. The method according to claim 8, including the use of a sensor adapted to determine the traffic situation and provide it to the driver assistance system, wherein the sensor is adapted to detect an operating state of the brake, an operating state of a wheel provided with the brake, an operating state of an engine, and/or an action of a driver of the motor vehicle, to determine a traffic situation concerning a brake pedal and/or accelerator pedal of the motor vehicle.

10. (canceled)

11. (canceled)

12. A system for adapting the braking behaviour of a brake of a motor vehicle to a traffic situation comprising: a brake; a control unit configured to: adjust a clearance of the brake to a value L.sub.K; determine the traffic situation; and adjust the clearance to a value L.sub.A based on the determined traffic situation, where 0<L.sub.A<L.sub.K is satisfied.

13. The system according to claim 12, wherein the adjustment of the clearance to a value L.sub.K is carried out when the motor vehicle is at a standstill, wherein the brake includes a brake lining with a contact surface and a friction surface, wherein adjusting the clearance to a value L.sub.K involves contacting the contact surface with the friction surface and adjusting the value L.sub.K between the contact surface and the friction surface.

14. The system according to claim 12, wherein the clearance is readjusted each time the motor vehicle is at a standstill.

15. The system according to claim 12, wherein the control unit is further configured to determine a changed traffic situation; and adjust the clearance to a value L.sub.B, where 0<L.sub.BL.sub.K is satisfied with L.sub.BL.sub.A.

16. The system according to claim 12, wherein the traffic situation includes a driving situation and/or a driver situation.

17. The system according to claim 12, wherein the control unit is further configured to determine a changed traffic situation; and adjust the clearance to a value L.sub.B, where 0<L.sub.B<L.sub.A is satisfied, wherein the traffic situation involves detection of a reduction in pressure exerted on an accelerator pedal of the motor vehicle, and the changed traffic situation involves detecting pressure exerted by touching or operating a brake pedal of the motor vehicle.

18. The system according to claim 12, wherein the brake is an electromechanical brake, wherein the motor vehicle has multiple brakes, wherein the clearance of each of the multiple brakes is adjusted individually or axle-by-axle.

19. The system according to claim 12, wherein the control unit comprises a driver assistance system control unit to provide a first control signal for adjusting the clearance and a second control signal for adapting the clearance to the brake.

20. The system according to claim 19, further comprising a sensor adapted to determine the traffic situation and provide it to the driver assistance system control unit, wherein the sensor is adapted to detect an operating state of the brake, an operating state of a wheel provided with the brake, an operating state of an engine, and/or an action of a driver of the motor vehicle, to determine a traffic situation concerning a brake pedal and/or accelerator pedal of the motor vehicle.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] The method is explained in detail below using multiple figures. In the figures:

[0029] FIG. 1 shows a schematic block circuit diagram of a method for adapting the braking behaviour of a brake to a traffic situation;

[0030] FIG. 2a shows a schematic view of a brake, the clearance of which is set to a value L.sub.K and FIG. 2b shows an enlargement of the schematic view of a brake from FIG. 2a;

[0031] FIG. 3 shows a schematic view of a brake, the clearance of which is reduced to zero as part of the adjustment;

[0032] FIG. 4 shows a schematic view of a brake with the clearance adjusted to a value L.sub.A.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a schematic view of a method 10 for adapting a braking behaviour of a brake 40 in the form of an electromechanical brake to a traffic situation. The brake 40, which is in the form, for example, of a wheel brake and which has a clearance 30 which is adjusted within the framework of the method 10 according to the disclosure, is a component of a brake system of a motor vehicle that is not shown. The brake system can be an integrated brake system, which is a unit in which a number of functions are combined in a compact design.

[0034] In the method 10, which is shown schematically in FIG. 1, a clearance 30 of the brake 40 is set to a value L.sub.K in a first step 12. The clearance 30 can be set to the value L.sub.K every time the motor vehicle is at a standstill 20 or stops, for example when the motor vehicle stops at a traffic light, at a pedestrian crossing, when turning off or parking the motor vehicle.

[0035] As can be seen from FIGS. 2a, 2b and 3, the brake 40 is in the form of a floating calliper brake here by way of example. The brake 40 has a housing 42 with a brake cylinder 48, in which a brake piston 54 is coaxially connected via a spindle 52 to a drive unit 50 containing a motor and a gearbox. The brake piston 54 is sealed from the brake cylinder 48 by a bellows 58 and can be operated by a driver by a brake pedal via the drive unit 50 and spindle 52.

[0036] When the brake 40 is actuated, the brake piston 54 with a first brake lining 60a arranged on it is displaced along a first travel path 56 by the spindle 52 and the drive unit 50 towards a brake disc 70 until a contact surface 62 of the first brake lining 60a contacts the friction surface 72 of the brake disc 70.

[0037] The brake piston 54 is supported by a housing 42 supported in a floating manner on a fastening device 44 and moving along a first travel path 46. The housing 42 grips the brake disc 70 laterally and allows a contact surface 62 of a second brake lining 60b to press against the friction surface 72 of the brake disc 70 from the other side.

[0038] In the present case, a control unit (not shown) in the form of a driver assistance system by way of example in conjunction with the drive unit 50, provides actuation of the brakes 40 on the basis, inter alia, of signals provided by sensors that are not shown, and provides corresponding driving and braking assistance functions. These driving and braking assistance functions are used for the purpose of autonomous or semi-autonomous driving and braking with increased safety and reliability.

[0039] In step 12 for adjusting the clearance 30, the contact surfaces 62 of the brake disc 70 and the friction surfaces 72 of the brake linings 60a, 60b are first brought into contact. For example, the contact of the contact surfaces 62 with the friction surfaces 72 can be detected by a distance sensor (not shown) which determines a distance 74 between the brake piston 54 and the drive unit 50 and a corresponding detection signal can be transmitted to the control unit. The clearance 30 takes a value of zero, as shown in FIG. 3.

[0040] Also in step 12, as can be seen from FIGS. 2a and 2b, the value L.sub.K between the contact surface 62 and the friction surface 72 is set by retracting the brake piston 54. This can also be carried out with the distance sensor that is not shown. Signals generated by the distance sensor are transmitted to the control unit. After starting the vehicle, the housing 42 is moved along a second travel path 46 in such a way that the predetermined value L.sub.K, in the present case by way of example 0.3 mm, is obtained on average between the first brake lining 60a and the friction surface 72 and between the second brake lining 60a and the friction surface 72. The brake 40 can also be in the form of a fixed calliper brake or of a drum brake.

[0041] In a second step 14, a driver situation is determined as an example traffic situation. In the present exemplary case, the determination of the driver's situation is carried out by sensors (not shown) attached to the brake pedal and the accelerator pedal. A sensor attached to the brake pedal may be adapted to detect whether the driver's foot is touching the brake 40 without applying it. Furthermore, the sensor attached to the accelerator pedal can be adapted to determine whether and to what extent the accelerator pedal is actuated. Signals generated by the sensors are transmitted to the control unit. Instead of the driver's situation, one or more other traffic situations, such as a driving situation, can also be determined.

[0042] In a third step shown in FIG. 4, the clearance 16 is adjusted to a value L.sub.A on the basis of the determined traffic situation, for example removal of a driver's foot from the accelerator pedal, wherein the condition 0<L.sub.A<L.sub.K is satisfied. The value L.sub.A thus provides a clearance that is adapted or optimized to the respective traffic situation. This ensures that the clearance can be adapted to the current traffic situation in the best possible way. In addition, on the one hand too large a clearance which may involve a braking process that may take a long time or too long a time is avoided, and on the other hand too small a clearance which involves unnecessary wear and tear of the friction partners is avoided.

[0043] Once the clearance 30 has been adjusted to a value L.sub.A, it is determined by sensor whether the vehicle is at a standstill 20. If the result is positive, the clearance 30 is set again by repeating step 12. As a result it can be ensured that all wheel brakes of the motor vehicle have the same clearance 30. As a result, any braking of the motor vehicle that may be necessary at a later date can be carried out evenly and without the motor vehicle swerving.

[0044] For example, readjusting the clearance 30 in step 18 to a value L.sub.B can be carried out as soon as the driver's foot touches the brake 40 without applying it. In this case, it is assumed that the driver does indeed intend to apply the brake 40, so that the clearance 30 is further reduced to a value L.sub.K, where 0<L.sub.B<L.sub.A applies. As a result, the clearance, and thus the braking behaviour, of the motor vehicle can be adapted or optimized to the current traffic situation.

[0045] For example, the readjustment explained above and made in step 18 can also be done in response to the driver pressing the accelerator pedal again. In this case, it is assumed that the driver intends not to apply the brake 40, so that the clearance 30 is increased to a value L.sub.B, where L.sub.A<L.sub.BL.sub.K is satisfied. After adjusting the clearance 30 to the value L.sub.B, it is determined whether the motor vehicle is at a standstill 20. If the result is positive, the clearance 30 is set again according to step 12.