Adjusting device for a disc brake

1. A readjustment device for compensating wear of one or more brake pads and/or a brake disc of a pneumatically actuable disc brake for a vehicle, the readjustment device comprising:

a mechanical actuator is configured to convert a rotational movement of a brake lever into a rotational movement of a shaft, wherein the shaft rotates at least one threaded spindle, which acts on one of the brake pads, into a rotatory movement, the at least one threaded spindle being arranged concentric with the shaft, wherein

the readjustment device is configured to carry out during brake application an advancing stroke of a first threaded spindle of the at least one threaded spindle when an air clearance between the brake disc and one of the one or more brake pads is greater than a predetermined air clearance and a reverse rotary stroke of the first threaded spindle when an air clearance between the brake disc and one of the one or more brake pads is smaller than a predetermined air clearance, the advancing stroke and the reverse rotary stroke of the first threaded spindle being terminable by one or more ball ramp couplings of the readjustment device of the first threaded spindle switching between a torque-transmitting mode and a non-torque-transmitting mode.

2. The readjustment device as claimed in claim 1 , wherein

a magnitude of the reverse rotary stroke of the readjustment device is defined by a defined spacing h between two geometry formations of the readjustment device, and

the spacing h is defined in a defined operating state of the readjustment device.

3. The readjustment device as claimed in claim 2 , wherein

the defined operating state is defined by virtue of the brake pad being caused by the readjustment device to just make contact with the brake disc of the disc brake.

4. The readjustment device as claimed in claim 2 , wherein

the geometry formations which define the spacing h are a ramp starting point and a ramp end point or ramp switching point of a switching coupling.

5. The readjustment device as claimed in claim 4 , wherein

the mechanical actuator has a transmission.

6. The readjustment device as claimed in claim 5 , wherein

the transmission is a spur gear transmission.

7. The readjustment device as claimed in claim 5 , wherein

the transmission is a two-stage transmission.

8. The readjustment device as claimed in claim 5 , wherein

the transmission has a crown wheel toothed segment and a stepped gearwheel.

9. The readjustment device as claimed in claim 8 , wherein

the crown wheel toothed segment can be brought out of engagement with a pinion section of the stepped gearwheel.

10. The readjustment device as claimed in claim 8 , wherein

the shaft has a pinion section, wherein the pinion section is operatively connected to the wheel section of the stepped gearwheel.

11. The readjustment device as claimed in claim 8 , wherein

the shaft has a spline toothing section, wherein the spline toothing section is operatively connected to a spline toothing hub.

12. The readjustment device as claimed in claim 11 , wherein

the shaft has a bearing section by which the shaft is mounted rotatably in a housing via a bearing.

13. The readjustment device as claimed in claim 12 , wherein

the bearing is a deep groove ball bearing.

14. The readjustment device as claimed in claim 13 , wherein

the brake caliper has an opening or bore in which the housing is inserted and fixed in an axial direction.

15. The readjustment device as claimed in claim 14 , wherein

the bearing is fixed in an axial direction by a shoulder of the housing.

16. The readjustment device as claimed in claim 12 , wherein

the shaft has a freewheel section, and the freewheel section of the shaft extends through the hub of a freewheel.

17. The readjustment device as claimed in claim 16 , wherein

an end of the shaft facing away from the bearing section has an axially central internal threaded blind hole into which a hexagon screw is inserted, by which a center sleeve is fastened to the shaft.

18. The readjustment device as claimed in claim 17 , wherein

the center sleeve coaxially adjoins the shaft.

19. The readjustment device as claimed in claim 18 , wherein

the first threaded spindle protrudes, with its end facing toward the shaft, at least partially into the center sleeve.

20. The readjustment device as claimed in claim 11 , wherein

the readjustment device has a drive disc.

21. The readjustment device as claimed in claim 20 , wherein

the drive disc has the spline toothing hub.

22. The readjustment device as claimed in claim 20 , wherein

an upper bearing ring forms, with the drive disc and rolling bodies, a first rolling bearing, by which the drive disc is rotatably mounted.

23. The readjustment device as claimed in claim 22 , wherein

the drive disc has, on its upper face side, a channel in which the rolling bodies of the first rolling bearing of the drive disc roll.

24. The readjustment device as claimed in claim 23 , wherein

the upper bearing ring is fastened to the drive disc at the circumference of the latter and engages in a corresponding groove.

25. The readjustment device as claimed in claim 24 , wherein

a second rolling bearing, by which the drive disc is rotatably mounted, is formed by a plurality of rolling bodies and the switching coupling.

26. The readjustment device as claimed in claim 25 , wherein

the drive disc has, on its lower face side, a channel in which the rolling bodies of the second rolling bearing of the drive disc roll.

27. The readjustment device as claimed in claim 26 , wherein

the drive disc has, on its lower face side, a cylindrical depression, wherein a transition between the base of the depression and the side surface of the depression has a cylindrical depression radius.

28. The readjustment device as claimed in claim 27 , wherein

the cylindrical depression radius forms a running surface of the rolling bodies of a first of the one or more couplings, wherein the first coupling is a first ball ramp coupling of the one or more ball ramp couplings.

29. The readjustment device as claimed in claim 28 , wherein

the counterpart running surface of the first ball ramp coupling is formed by a conical projection of an output disc.

30. The readjustment device as claimed in claim 29 , wherein

the output disc has a bell-shaped cross section.

31. The readjustment device as claimed in claim 30 , wherein

the output disc furthermore has a central bore through which the shaft extends.

32. The readjustment device as claimed in claim 31 , wherein

the output disc has an output disc radius on its inner side.

33. The readjustment device as claimed in claim 32 , wherein

the output disc radius forms a running surface of the rolling bodies of a second ball ramp coupling of the one or more couplings.

34. The readjustment device as claimed in claim 33 , wherein

the counterpart running surface of the second ball ramp coupling is formed by a conical projection of a freewheel outer ring.

35. The readjustment device as claimed in claim 34 , wherein

the freewheel outer ring forms, together with the freewheel section of the shaft and the freewheel, a freewheel coupling which permits rotation of the shaft relative to the first threaded spindle in one direction of rotation and blocks rotation of the shaft relative to the first threaded spindle in an opposite direction of rotation.

36. The readjustment device as claimed in claim 35 , wherein

a preload spring is supported on a centering ring, wherein the preload spring is a helical torsion spring.

37. The readjustment device as claimed in claim 36 , wherein

the preload spring extends between the centering ring and a further centering ring which is arranged coaxially with respect to the shaft, wherein the centering ring is inserted in a spring sleeve.

38. The readjustment device as claimed in claim 37 , wherein

the spring sleeve has, on its circumference, a plurality of output elements which are each molded integrally onto the spring sleeve, wherein the output elements are each formed in the manner of a toothing profile.

39. The readjustment device as claimed in claim 38 , wherein

torque, introduced into the spring sleeve, of the shaft is transmitted by the output elements via transmission elements to an internal profile of an output wheel.

40. The readjustment device as claimed in claim 37 , wherein

the spring sleeve engages with a projection around a geometrically corresponding collar of the output disc and is connected rotationally conjointly to the output disc.

41. The readjustment device as claimed in claim 40 , wherein

the spring sleeve surrounds the preload spring and has an opening at its lower end, wherein the spring sleeve is connected rotationally conjointly to a center sleeve.

42. The readjustment device as claimed in claim 41 , wherein

the readjustment device has at least one output wheel.

43. The readjustment device as claimed in claim 42 , wherein

the output wheel is connected rotationally conjointly to the first threaded spindle.

44. The readjustment device as claimed in claim 42 , wherein

the output wheel has a synchronization device.

45. The readjustment device as claimed in claim 44 , wherein

the synchronization device is formed as a sprocket toothing or as an involute toothing.

46. The readjustment device as claimed in claim 45 , wherein

the output wheel has an internal profile, wherein the internal profile is a toothing profile.

47. The readjustment device as claimed in claim 46 , wherein

the output wheel has an internal thread which is operatively connected to an external thread of the first threaded spindle, and a spindle drive is thus formed.

48. The readjustment device as claimed in claim 47 , wherein

the spindle drive converts a torque of the threaded shaft into a translationally acting force which acts on the at least one brake pad or on the brake disc of the disc brake.