BRAKE PAD FOR A DISK BRAKE SYSTEM AND DISK BRAKE SYSTEM

Abstract

The application relates to a brake pad (2) for a disk brake system and to a disk brake system. The proposed brake pad (2) comprises a back plate (5) having a front side (4) for facing a brake disk (1) of the disk brake system and a friction layer (3) arranged on the front side (4) of the back plate (5) for contacting a friction surface of the brake disk (1). The back plate (5) comprises a guiding protrusion (9) configured to be slidably received within a guiding recess (14) of a carrier (13) of the disk brake system. The guiding protrusion (9) of the back plate (5) comprises a bulging portion (10). The bulging portion (10) is configured to extend toward a guiding surface (15) of the guiding recess (14) of the carrier (13) to reduce a gap width between the guiding protrusion (9) of the back plate (5) in the region of the bulging portion (10) and an adjacent part of the disk brake system.

Claims

1. A brake pad (2) for a disk brake system, comprising a back plate (5) having a front side (4) for facing a brake disk (1) of the disk brake system and a friction layer (3) arranged on the front side (4) of the back plate (5) for contacting a friction surface of the brake disk (1), wherein the back plate (5) comprises a guiding protrusion (9) configured to be slidably received within a guiding recess (14) of a carrier (13) of the disk brake system, characterized in that the guiding protrusion (9) of the back plate (5) comprises a bulging portion (10) configured to extend toward a guiding surface (15) of the guiding recess (14) of the carrier (13) to reduce a gap width between the guiding protrusion (9) of the back plate (5) in the region of the bulging portion (10) and an adjacent part of the disk brake system.

2. The brake pad (2) of claim 1, characterized in that the back plate (5) comprises a back plate body, wherein the guiding protrusion (9) of the back plate (5) protrudes in a tangential direction from the back plate body.

3. The brake pad (2) of claim 2, characterized in that the bulging portion (10) has, at least in part, essentially the shape of a spherical cap.

4. The brake pad (2) of claim 3, characterized in that the bulging portion (10) defines a tip portion that has a radius of curvature of at most 5 mm.

5. The brake pad (2) of claim 2, characterized in that the bulging portion (10) extends in a tangential direction.

6. The brake pad (2) of claim 5, characterized in that the bulging portion (10) extends in a radial direction.

7. The brake pad (2) of claim 6, characterized in that the guiding protrusion (9) of the back plate (5) comprises a second bulging portion (10″) configured to extend toward the guiding surface (15) of the guiding recess (14) of the carrier (13) to reduce a gap width between the guiding protrusion (9) of the back plate (5) and the adjacent part in the region of the second bulging portion (10″).

8. The brake pad (2) of claim 7, characterized in that the bulging portion (10) and the second bulging portion (10″) both extend in the tangential direction and/or in that the bulging portion (10) and the second bulging (10″) portion both extend in the radial direction.

9. The brake pad (2) of claim 2, characterized in that the guiding protrusion (9) is essentially spherical.

10. The brake pad (2) of claim 1, characterized in that at least a part of a surface area of the bulging portion (10) is formed by or covered with a non-stick material.

11. The brake pad (2) of claim 1, characterized in that the guiding protrusion (9) comprises a guiding protrusion body (11), wherein the bulging portion (10) is attached to the guiding protrusion body (11), and the guiding protrusion body (11) as well as the bulging portion (10) are formed by a one-piece part.

12. The brake pad (2) of claim 1, characterized in that the back plate (5) comprises a back plate body (8), wherein the guiding protrusion (9) and the back plate body (8) are formed as joined parts.

13. A disk brake system comprising a brake pad (2) according to claim 1 and the carrier (13), wherein the brake pad (2) is configured to slide with respect to the carrier (13) in an axial direction upon brake application.

14. The disk brake system of claim 13, characterized in that the gap width between the guiding protrusion (9) of the back plate (5) in the region of the bulging portion (10) and the adjacent part of the disk brake system is at most 0.8 mm.

Description

[0028] Exemplary embodiments will be described in conjunction with the following figures.

[0029] FIG. 1 shows a schematic cross sectional illustration of a brake pad and a brake disk,

[0030] FIG. 2 shows a perspective view of a brake pad,

[0031] FIGS. 3 and 4 show schematic cross-sectional views of portions of a carrier and the brake pad according to different embodiments,

[0032] FIGS. 5 to 7 show schematic cross-sectional views of portions of a carrier and the brake pad according to further embodiments,

[0033] FIGS. 8 and 9 show schematic cross-sectional views of a portion of a back plate according to other embodiments, and

[0034] FIGS. 10 to 12 show cross-sectional views according to further embodiments.

[0035] FIG. 1 shows a brake disk 1 of a of a disk brake system for a vehicle. The disk brake system may comprise a caliper housing, a caliper finger and a brake piston. The disk brake system further comprises a brake pad 2, which may be attached relative to the caliper finger or to the brake piston such that upon application of the brake the caliper finger or the brake piston pushes the brake pad 2 in an axial direction toward the brake disk 1. The brake pad 2 has a friction layer 3, which is pushed against a friction surface of the brake disk 1 upon actuation of the disk brake system, e.g., hydraulic or electric actuation. The friction layer 3 contains a material that shows a good stopping performance and heat transfer when engaging with the brake disk 1. The friction layer 3 is attached to a front side 4 of a back plate 5, which provides structural stability to the brake pad 2. The brake piston or the caliper finger is configured to push against a back side 6 of the back plate 5 to push the friction layer 3 against the brake disk 1. In most embodiments, the back plate 5 is made of a metal, in particular steel. A thickness of the back plate 5 may be, e.g., 5 mm. The friction layer 3 can have a thickness of at least 8 mm and/or at most 15 mm, for example. The material of the friction layer 3 can for instance comprise at least one of copper, iron sulphide, graphite, zinc powder, basalt, calcium carbonate, tin sulphide, zinc aluminium, phenolic resin, rubber dust and mineral fibre. These materials show good stopping performance and heat transfer when engaging with the brake disk.

[0036] FIG. 2 shows a perspective view of a brake pad 2. Corresponding and reoccurring features shown in the different figures are denoted using the same reference numerals. The friction layer 3 of the brake pad 2 is fixed to the front side 4 of the back plate 5. A clip-on-shim 7 is attached to the back side 6 of the back plate 5 for noise dampening. The back plate 5 comprises a back plate body 8 forming the main portion of the back plate 5 and carrying the friction layer 3. The back plate 5 further comprises a pair of guiding protrusions 9, 9′ formed at the two tangential sides of the back plate 5 and each configured to be received within a respective guiding recess of a carrier of the disk brake system. In the embodiment shown, the back plate body 5 and the guiding protrusions 9, 9′ are formed as a one-piece, non-joined part.

[0037] The guiding protrusions 9, 9′ each have a bulging portion 10, 10′ extending in a tangential direction from a guiding protrusion body 11, 11′. The bulging portions 10, 10′ reduce a width of a gap between the brake pad 2 and an adjacent part of the disk brake system, e.g., the carrier or a pad spring, and enable a well-defined contact, which was found to lead to a reduction of noise occurrence. The bulging portions 10, 10′ each have a rounded tip portion 12, 12′ facing the guiding recesses of the carrier. The tip portions 12, 12′ can be approximately circular in a cross-section. In the embodiment shown, the tip portions 12, 12′ have the shape of a segment of a cylinder having a cylinder axis in the axial direction. In other embodiments, the tip portions 12, 12′ of the bulging portions 10, 10′ can each have the shape of a spherical cap. The rounded tip portions may have a radius of curvature of, e.g., 2 mm or 3 mm to yield a defined contact area with the carrier. In some embodiments, the bulging portions 10, 10′ are formed together with the guiding protrusion bodies 11, 11′ as a single non-joined part. The bulging portions 10, 10′ may have a PTFE coating and/or may be formed by a material that is softer than the material of the guiding protrusion bodies 11, 11′ in some embodiments.

[0038] FIGS. 3 and show schematic cross-sectional views of portions of a carrier 13 and the brake pad 2 according to different embodiments. The brake pad 2 of FIG. 3 has a guiding protrusion 9 that is circular in cross-section. The guiding protrusion 9 may be essentially spherical or cylindrical with a cylinder axis in the axial direction, i.e., into the paper plane in the figure. Rounded sections of the guiding protrusion that extend from the guiding protrusion body 11 into a positive radial direction (upward), a tangential direction (to the right), and a negative direction (downward) form the bulging portion 10 with the tip portion 12, as well as a second bulging portion 10″ with a corresponding tip portion 12″ as well as a third bulging portion 10′″ with a corresponding tip portion 12″′, respectively. The bulging portions extending in the radial direction form undercut portions. In the embodiment shown, a radius or curvature of the bulging and tip portions tip portions can be, e.g., 8 mm or smaller. Particularly in this embodiment, the guiding protrusion 9 and the back plate body 8 may be formed as separate parts attached to one another, e.g., by screwing or welding.

[0039] The guiding protrusion 9 of the back plate 5 of the brake pad 2 is slidably received within a guiding recess 14 of the carrier 13. The guiding recess 14 defines guiding surfaces, one of which is marked using reference numeral 15 in the figure. As compared with a rectangular guiding protrusion, the presence of the bulging portions and tip portions as shown in the figures leads to a reduction of a width of a gap between the carrier 13 and the brake pad 2. In the region of the bulging portions 10, 10″, 10″′ the width of the gap is minimal and amounts to less than 0.8 mm, for example 0.4 mm, when the brake is not applied. Upon application of the brake, the bulging portions or at least some of the bulging portions may come in direct contact with the guiding recess 14 of the carrier 13 and form a point-like contact area on the bulging portion in the case of the spherical guiding protrusion 9 or a line-shaped contact area in the case of the cylindrical guiding protrusion 9.

[0040] FIG. 4 illustrates that a pad spring 16 (as known in the art) can be arranged between the brake pad 2 and the carrier 13. In this case, the gap width be-tween the pad spring and the guiding protrusion 9 in the region of the bulging portions 10, 10″, 10′″ is, e.g., 0.4 mm. A gap width between the guiding surface 15 of the guiding recess 14 of the carrier 13 and an outer surface of the pad spring 16 in the region of the bulging portions 10, 10″, 10′″ of the guiding protrusion 9 of the back plate 5 of the brake pad 2 is, e.g., 0.6 mm. The pad spring 16 is typically formed by a sheet metal part.

[0041] FIGS. 5 to 7 show schematic cross-sectional views of portions of a carrier 13 and the brake pad 2 according to further embodiments. These embodiments correspond to the embodiments discussed above, except that the guiding surface 15 of the guiding recess 14 of the carrier 13 is concave. The guiding recess 14 of the carrier 13 according to the embodiment of FIG. 5 is formed by a half cylindrical recess. The guiding recess 14 shown in FIG. 6 has a guiding recess 14 formed by a concave guiding surface 15 delimiting the guiding recess 14 in the tangential direction and flat guiding surfaces 15′, 15″ delimiting the guiding recess 14 in the positive and negative radial directions, respectively. FIG. 7 illustrates that the pad spring 16 can be provided, as explained above.

[0042] FIGS. 8 and 9 illustrate guiding protrusions 9 according to other embodiments. These guiding protrusions 9 have two bulging portions 10, 10′ extending from the guiding protrusion body 11 in the positive radial direction, two bulging portions 10″, 10″′ extending from the guiding protrusion body 11 in the tangential direction, and two bulging portions 10″″, 10″″′ extending from the guiding protrusion body 11 in the negative radial direction. Pairs of the bulging portions are arranged side-by-side. While the guiding protrusion body 11 of FIG. 8 has upper and lower surfaces 17, 18 that are essentially parallel, the upper and lower surfaces 17, 18 of the guiding protrusion body 11 according to the embodiment of FIG. 9 are tapered in the tangential direction.

[0043] FIGS. 10 to 12 illustrate cross-sectional views of the guiding protrusion 9 of the back plate 5 of the brake pad 2 according to further embodiments. Features of the different embodiments which are merely disclosed in the exemplary embodiments may be combined with one another and may also be claimed individually.

LIST OF REFERENCE NUMERALS

[0044] 1 Brake disk

[0045] 2 Brake pad

[0046] 3 Friction layer

[0047] 4 Front side of back plate

[0048] 5 Back plate

[0049] 6 Back side of back plate

[0050] 7 Clip-on-shim

[0051] 8 Back plate body

[0052] 9, 9′ Guiding protrusions

[0053] 10, 10′, 10″, 10′″, 10″″, 10″″′ Bulging portions

[0054] 11, 11′ Guiding protrusion bodies

[0055] 12, 12′ Tip portions

[0056] 13 Carrier

[0057] 14 Guiding recess

[0058] 15, 15′, 15″ Guiding surfaces

[0059] 16 Pad spring

[0060] 17 Upper surface of guiding protrusion body

[0061] 18 Lower surface of guiding protrusion body