DEVICE FOR RESTORING BRAKE PADS, AND DISC BRAKE

Abstract

A device for supporting and guiding a brake pad backplate and a brake pad arranged thereon in a pad slot of a disc brake, including a restoring device formed by two separately acting restoring elements. One restoring element is formed by a wire spring which serves to restore the lower portion of the brake pad backplate, while the other restoring element is formed by a pad hold-down spring which is capable of restoring the upper portion of the brake pad backplate.

Claims

1. A device for supporting and guiding a brake pad backplate and a brake pad arranged thereon in a pad slot of a disc brake, having a restoring device which interacts with the brake pad backplate and is designed to generate a restoring force when the brake pad moves in an axial direction as a result of the a braking stroke, wherein the restoring device comprises a first restoring element, which is designed and arranged to restore a lower region of the brake pad backplate, and a second restoring element, which is separate therefrom and is designed and arranged to restore the an upper region of the brake pad backplate opposite the lower region; characterized in that the first restoring element is designed as a wire spring which is arranged on a rear side of the brake pad backplate between its both sides by means of at least one fastening element to prevent loss in such a way that free ends of which, abutting against the two sides of the brake pad backplate, extend in the axial direction, and act between lateral guide surfaces of the pad slot and the brake pad backplate in such a way that the brake pad backplate is slidingly supported on the lateral guide surfaces of the pad slot, and that the wire spring is only able to absorb axial forces; and that the second restoring element is designed as a pad hold-down spring which is arranged on the brake pad backplate and supported against an abutment plate of a brake caliper, wherein the pad hold-down spring transversely with respect to its longitudinal extent comprises a defined sequence of differently inclined contact surfaces, curvatures of which being selected in such a way that the pad hold-down spring can be tilted between the abutment plate and the brake pad backplate during the braking stroke and which are configured such to produce a restoring torque acting in a direction opposite to a direction of tilt as a result of the tilting movement.

2. The device according to claim 1, in which the first restoring element and/or the second restoring element is/are under a defined pretension.

3-4. (canceled)

5. The device according to claim 1, in which the at least one fastening element is adapted to adjust the restoring force.

6. The device according to claim 5, in which the wire spring is movably arranged relative to the at least one fastening element.

7. The device according to claim 6, in which a degree of mobility of the wire spring relative to the at least one fastening element co-determines the restoring force at least in part.

8-13. (canceled)

14. The device according to claim 1, in which an angle of inclination of the inclined contact surfaces is selected such that a radius with respect to a tilting movement corresponds to at least half of a distance between a top surface of the brake pad backplate and a bottom surface of the abutment plate.

15. The device according to claim 1, in which the wire spring and the pad hold-down spring are tuned with respect to each another in terms of arrangement and resulting elastic deformation, taking into account dimensions and weight of a unit consisting of brake pad and brake pad backplate, in such a way that the respective resulting restoring forces and/or restoring torques are essentially equal in magnitude.

16. A disc brake comprising the device according to claim 1.

17. A brake pad backplate with a brake pad for arrangement and guidance in a brake slot of a disc brake, having a restoring element which is designed and arranged on the brake pad backplate in such a way that a lower region of the brake pad backplate can be restored; characterized in that the restoring element is designed as a wire spring which is arranged on a rear side of the brake pad backplate between its both sides by means of at least one fastening element to prevent loss in such a way that free ends of which, abutting against the two sides of the brake pad backplate, extend in an axial direction, and act between lateral guide surfaces of the pad slot and the brake pad backplate in such a way that the brake pad backplate is slidingly supported on the lateral guide surfaces of the pad slot, and that the wire spring is only able to absorb axial forces.

18. The brake pad backplate according to claim 17, in which the wire spring is under a defined pretension.

19-20. (canceled)

21. The brake pad backplate according to claim 17, in which the wire spring is movably arranged relative to the at least one fastening element.

22-23. (canceled)

24. A brake pad backplate with a brake pad for arrangement and guidance in a brake slot of a disc brake, having a restoring element which is designed and arranged on the brake pad backplate in such a way that an upper region of the brake pad backplate can be restored; characterized in that the restoring element is designed as a pad hold-down spring which is arranged on the brake pad backplate and supported against an abutment plate of a brake caliper, wherein the pad hold-down spring transversely with respect to its longitudinal extent comprises a defined sequence of differently inclined contact surfaces, curvatures of which being selected in such a way that the pad hold-down spring can be tilted between the abutment plate and the brake pad backplate during a braking stroke and which are configured such to produce a restoring torque acting in a direction opposite to a direction of tilt as a result of the tilting movement.

25-27. (canceled)

28. A pad hold-down spring for a brake pad backplate for a disc brake, which comprises two openings into which lugs of the brake pad backplate can engage in order to secure the pad hold-down spring on the brake pad backplate in such a way that it cannot lose, a sequence of differently inclined contact surfaces extends between the two openings, by means of which the pad hold-down spring can be supported on an- stationary abutment of the disc brake, and curvatures of the contact surfaces being selected transversely with respect to longitudinal extent of the pad hold-down spring in such a way that the pad hold-down spring can be tilted between the abutment and the brake pad backplate during a braking stroke.

29. The pad hold-down spring according to claim 28, in which said spring is adapted to produce a torque acting in a direction opposite to a direction of tilt and in relation to the brake pad backplate as a result of a tilting movement.

30. The pad hold-down spring according to claim 28, in which an angle of inclination of the inclined contact surfaces is selected such that a radius with respect to a tilting movement corresponds to at least half of a distance between a top surface of the brake pad backplate and a bottom surface of the abutment.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further features and advantages of the invention will be apparent from the following description of the embodiments illustrated with reference to the accompanying drawings, in which:

[0035] FIG. 1 schematically is a rear view of a brake pad backplate with a mounted wire spring in a first embodiment and, in comparison, the wire spring in an unmounted state;

[0036] FIG. 2 schematically is a rear view of a brake pad backplate with a mounted wire spring in a second embodiment and, in comparison, the wire spring in an unmounted state;

[0037] FIG. 3 is a top view of the brake pad backplate and the wire spring from FIG. 2;

[0038] FIG. 4 is a perspective view with brake pads inserted in a brake carrier with the wire spring according to the second embodiment;

[0039] FIG. 5 is a partial view in cross-section along A-A from FIG. 2;

[0040] FIG. 6a is a perspective view of an upper restoring element;

[0041] FIG. 6b is another perspective view of the upper restoring element;

[0042] FIG. 6c is a view in the longitudinal direction of the restoring element; and

[0043] FIGS. 7a to 7c show a schematic sequence of different sectional views illustrating the tilting motion.

DETAILED DESCRIPTION OF THE INVENTION

[0044] FIG. 1 shows an exemplary rear view of a rear plate or brake pad backplate 1.

[0045] The brake pad backplate 1 comprises a first restoring element in the form of a wire spring 2 in a first embodiment and a second restoring element in the form of a pad hold-down spring 3. The restoring elements 2 and 3 are each independent components.

[0046] The wire spring 2 is bent accordingly and extends between both lateral ends of the brake pad backplate 1.

[0047] The wire spring 2 is arranged on the brake pad backplate 1 by means of two lateral fastening clips 4 and a central fastening clip 5, the fastening clips 4, 5 being riveted to the rear side, for example.

[0048] As can be seen in the two illustrations of FIG. 1, during assembly the wire spring 2 is forced inwards on both sides by the distance D, whereby the free ends 6 of the wire spring 2 then rest in a lateral recess 7 of the brake pad backplate 1 in each case, and in such a way that these free ends 6 extend exclusively in the axial direction, i.e. the direction of displaceability of the brake pad backplate 1 or the direction of application of the clamping force.

[0049] For stability reasons, the rear side of the brake pad backplate 1 may have a linear transverse guide 8 in which the transverse sections of the wire spring 2 are immovably enclosed.

[0050] FIGS. 2 to 5 show a second embodiment of a wire spring 9.

[0051] This is likewise fastened to the brake pad backplate 1 for a brake lining 14 by two lateral fastening clips 4 and a central fastening clip 5 in such a way that lateral compression by an offset D takes place on both sides, as a result of which a pretension is built up in the wire spring 9. The free ends 6 are received in the lateral recesses 7 of the brake pad backplate 1.

[0052] Just as in the first embodiment, this allows, as shown in FIG. 4, the brake pad backplate 1 together with the wire spring 9 to be inserted without difficulty into a pad slot 10 formed, inter alia, by the lateral horns 11 of a brake carrier 12 which slidably supports a sliding caliper not shown. For the purpose of easier insertion, the lateral surfaces or horns 11 may widen upwardly by inclined, chamfered or rounded surfaces, which is indicated schematically by the dashed lines.

[0053] Furthermore, as shown in FIG. 3, viewed from above, the wire spring 9 has such a shape that the lateral regions 13 thereof, which cooperate with the lateral fastening clips 4, are offset towards the center thereof by a distance d in the axial direction, as a result of which, when mounted on the backplate 1, namely by fastening via the central clip 5, a pretension can also be introduced into the wire spring 9.

[0054] Furthermore, the shape selected in this way with the offset d means that in the assembled state the wire spring 9 is not in contact with the inner surface of the clip 4, as shown in FIG. 5, but is spaced apart by a distance s which allows the wire spring 9 to move or be elastically deformed in the axial direction.

[0055] According to the invention, the wire springs 2 and 9 serve to ensure that, in particular, the lower edge of the brake pad is restored to an initial position when braking force is no longer applied. It can be seen that as a result of the assembly with the lateral fastening clips 4, a pretension is induced in the wire springs 2 and 9. The free ends 6 are bent towards the brake disc to increase the friction between the surfaces of the horns 11 of the carrier 12 and the wire springs 2, 9.

[0056] When the brake is applied and the brake pads are forced toward the brake disc, relative movement occurs between the brake pad backplate 1 and the horns 11 of the carrier 12. The resulting increased friction between the free ends 6 of the wire springs 2, 9 and the horns 11 of the carrier 12 causes an axial pretension in the wire springs 2, 9. After the brake is released, a return spring of the disc brake forces the brake piston back to its original retracted position in the caliper, allowing the caliper to move away from the brake disc. The energy stored in the wire springs 2, 9 as a result of both the predefined pretension and the counter- or pretension resulting from friction helps both the inner and outer brake pads to follow the brake piston and the brake caliper to their original positions, minus any wear generated and to be compensated for.

[0057] By introducing an axial pretension into the wire springs 2, 9, which acts against the holding clips 4, 5, it is possible to adjust the restoring force to a suitable level. Here, the dimension in relation to the lateral compression D, the axial bending d and the mobility s of the wire springs 2, 9 relative to the clips 4,5 can be set in such a way that the restoring force can be adjusted specifically, in particular also in comparison with the restoring force of the upper restoring element 3.

[0058] FIGS. 6a to 6c and 7a to 7c show an upper restoring element 3 according to the invention and its mode of operation, as it can be mounted or is mounted on a brake pad backplate 1.

[0059] The upper restoring element is formed by a specially designed pad hold-down spring 3, as used in a known manner between an abutment 15 of the brake caliper and the upper side of a brake pad backplate 1. The design and mode of operation of the pad hold-down spring 3 described below have an independent inventive significance.

[0060] The pad hold-down spring 3 has two openings 21 which serve to receive lugs 22 of the brake pad backplate 1. Typically, the pad hold-down spring 3 is clamped between the abutment 15 and the brake pad backplate 1 to exert a downward spring holding force so that the lugs 22 cannot move out of the openings 21.

[0061] In accordance with the invention, the pad hold-down spring 3 is tiltably mounted between the stationary abutment 15 of the brake caliper and a section 16 of the brake pad backplate 1. In the lower region, the spring 3 has a curvature 17 which supports the rotational mobility at this point, namely at the outer edges in the region of the openings 21 where the pad hold-down spring 3 actually rests on the surface 16 of the brake pad backplate 1.

[0062] Between the two openings 21, the pad hold-down spring 3 has a sequence of longitudinally extending, different contact surfaces with which it is supported on the abutment 15, a central, slightly curved contact surface 18 and lateral contact surfaces 19 and 20 which slope downwards at an angle thereto.

[0063] According to the invention, these contact surfaces 18, 19, 20, which, so to say, are curved outwards to form a curved tilting surface with respect to the abutment 15, are designed in such a way that a defined restoring behavior can be set, which comes into effect at the end of the braking stroke.

[0064] The restoring behavior resulting from this restoring element 3 with respect to the upper edge or the upper section is to be illustrated in more detail in FIGS. 7a to 7c by the sequence of schematic sectional views.

[0065] FIG. 7a shows the spring 3 in a rest position, in FIG. 7b in a slightly inclined intermediate position at the start of brake application with an initially slightly displaced brake lining and in FIG. 7c in a position with a fully achieved tilt angle.

[0066] Thereafter, further movement of the brake pad causes the spring 3 to slide or slip under the abutment plate 15.

[0067] As a result of the tilting movement along the abutment plate 15, there is also a compression of the spring element 3 in the direction towards the brake pad backplate 1. During tilting, a sequence of contact points or lines ultimately come into contact with the underside of the abutment plate 15 one after the other. Compression and rotation of the spring element 3 generate an axial pretension via a counteracting torque, which is shown as an example in FIG. 7c.

[0068] This torque then assists in the following, as soon as no more clamping force is applied and the brake pad does not move further, to bring the brake pad backplate 1 to its original position, in particular with respect to the upper section.

[0069] In a particular embodiment, such restoring behavior proves effective when a radius with respect to the contact points is more than half the distance with respect to the height between the upper contact surface to the abutment plate 15 and the lower support surface to the section 16.

[0070] Furthermore, the spring element 3 still has lateral flat end surfaces or edges 23 on both sides which limit the extent of tiltability to certain angles.