BRAKE PAD ASSEMBLY FOR A DISK BRAKE SYSTEM AND DISK BRAKE SYSTEM

Abstract

The application relates to a brake pad assembly (2) for a disk brake system. Further, the application relates to a disk brake system. The proposed brake pad assembly (2) comprises a back plate (4) having a front side for facing a brake disk (1) of the disk brake system and a back side (6). The brake pad assembly (2) further comprises a friction layer (3) arranged at the front side of the back plate (4) for contacting a friction surface the brake disk (1). In addition, the brake pad assembly (2) comprises a shim (5, 8, 12). The shim (5, 8, 12) comprises a copper layer (7, 11, 13, 17) for reducing squeal noises. The shim (5, 8, 12) is arranged on the back side (6) of the back plate (4).

Claims

1. A brake pad assembly for a disk brake system, comprising a back plate having a front side for facing a brake disk of the disk brake system and a back side, a friction layer arranged at the front side of the back plate for contacting a friction surface the brake disk, characterized by a shim comprising a copper layer for reducing squeal noises, wherein the shim is arranged on the back side of the back plate

2. The brake pad assembly of claim 1, characterized in that the copper layer contains at least 50% copper by weight.

3. The brake pad assembly of claim 1, wherein a thickness of the copper layer is less than 0.6 mm, in particular less than 0.3 mm.

4. The brake pad assembly of claim 1, wherein the shim comprises a metal layer glued to the copper layer.

5. The brake pad assembly of claim 1, characterized in that the shim is glued to the back side of the back plate.

6. The brake pad assembly of claim 1, characterized in that the shim comprises at least one clip for securing the shim to the back plate.

7. The brake pad assembly of claim 6, comprising an inner shim that is arranged between the shim and the back side of the back plate, wherein the inner shim comprises an inner shim metal layer, which is made of copper.

8. The brake pad assembly of claim 1, characterized in that the shim comprises a plurality of through holes.

9. The brake pad assembly of claim 1, characterized in that the copper layer has an in homogeneous thickness.

10. The brake pad assembly of claim 1, characterized in that the copper layer comprises one or more slots.

11. A disk brake system, comprising the brake pad assembly of claim 1 and further comprising a piston and a caliper finger movably coupled to the piston, wherein the brake pad assembly is mounted to one of the caliper finger and to the piston.

12. The disk brake system of claim 11, characterized in that the other one of the caliper finger and piston does not have a brake pad assembly having a shim with a copper layer mounted to it.

Description

[0021] Exemplary embodiments will be described in conjunction with the following figures.

[0022] FIG. 1 shows a schematic cross sectional illustration of a brake pad assembly and a brake disk,

[0023] FIG. 2 shows a schematic view of the brake pad assembly,

[0024] FIG. 3 shows a schematic cross sectional view of the brake pad assembly according to another embodiment, and

[0025] FIG. 4 shows a schematic cross sectional view of a copper layer.

[0026] 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 piston (not shown). The disk brake system further comprises a brake pad assembly 2, which may be attached to the caliper finger and/or to the piston. The brake pad assembly 2 has a friction layer 3, which is pushed against a friction surface of the brake disk 1 upon hydraulic or electric actuation of the disk brake system. 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 of a back plate 4, which provides structural stability to the brake pad assembly 2. The back plate 4 is typically held by the piston or the caliper finger such that the brake pad assembly 2 is mounted to the piston or caliper finger via the back plate 4.

[0027] A first shim 5 is mounted to a back side 6 of the back plate 4. The first shim 5 is glued to the back side 6 of the back plate 4 using a glue layer (not shown). The first shim 5 comprises a copper layer 7, which may in some embodiments be formed by a metal layer having a copper content of more than 90 percent by weight. The copper layer 7 of the first shim 5 may have a thickness of, e.g., 0.18 mm. The copper layer 7 of the first shim 5 ensures reliable suppression of squeal noises.

[0028] For further suppression of the squeal noises a second shim 8 is provided. The second shim 8 is a clip-on shim having resilient clips or tabs 9 that are configured to contact and engage with an edge surface 10 of the back plate 4 to attach the second shim 8 to the back plate 4, when the second shim 8 is installed. The second shim 8 comprises a copper layer 11, which like the copper layer 7 of the first shim 5 may in some embodiments be formed by a metal layer having a copper content of more than 90 percent by weight. Also, the copper layer 11 of the second shim 8 may have a thickness of, e.g., 0.18 mm. The resilient clips or tabs 9 are formed by folded protrusions in an edge portion of the copper layer 11 of the second shim 8.

[0029] The first shim 5 and the second shim 8 may be glued to one another in some embodiments. Also, the first shim 5 and/or the second shim 8 may additionally be fixed to the back plate 4 by using rivets or bolts. In addition, it is also possible in some embodiments, that only one of the first shim 5 and the second shim 8 comprises a copper layer 7, 11. The other one of the first shim 5 and the second shim 8 may, in some embodiments, comprise a layer made of a different metal, e.g., a steel layer, instead of the copper layer 7, 11.

[0030] The second shim 8 covers a back side of the first shim 5, the latter being arranged between the second shim 8 and the back plate 4. In this regard, the second shim 8 forms an outer shim and the first shim 5 forms an inner shim. The copper layer 7 of the first shim 5 may be referred to as an inner shim metal layer. An outer surface of the brake pad assembly 2 according to the depicted embodiment is formed by the copper layer 11 of the second shim 8. In other embodiments, an outer surface of the second shim 8 may be covered by a rubber or polytetrafluoroethylene coating.

[0031] FIG. 2 illustrates an illustration of the brake pad assembly 2 as viewed toward the brake disk 1 (not shown in this figure). Corresponding and reoccurring features shown in the different figures are denoted using the same reference numerals. As illustrated, the second shim 8 according to the exemplary embodiment comprises four resilient tabs 9 formed by different parts of the edge portion of the copper layer 11 of the second shim 8. As shown, the first shim 5 and the second shim 8 cover a substantial portion of an area of the back side 6 of the back plate 4, for example more than 50%. In other embodiments, the first shim 5 and the second shim 8 may cover more than 75% of the area of the back side 6 of the back plate 4.

[0032] FIG. 3 shows another aspect of the brake pad assembly 2. As shown, a multi-layer shim 12 is arranged on the back side 6 of the back plate 4. The multi-layer shim 12 comprises a copper layer 13 and another metal layer 14, which may in some embodiments be a steel layer or may be a copper layer in other embodiments that enable an improved noise reduction. The layers 13, 14 may have any or all of the characteristics described above or below with regard to the copper layers. In particular, the layers 13, 14 of the multi-layer shim 12 may each have a thickness of, e.g., 0.18 mm. The layers 13, 14 of the multi-layer shim 12 may be attached to one another by a glue layer 15 of the multi-layer shim 12. A thickness of the glue layer 15 may, e.g., be 0.1 mm.

[0033] The multi-layer 12 shim is attached to the back side 6 of the back plate 4 by another glue layer 16, which may also have a thickness of 0.1 mm, for example. Additionally or alternatively, the multi-layer shim 12 may be attached to the back plate 4 by other means, e.g., by resilient clips or tabs as described above. The resilient clips or tabs may in some embodiments be formed by folded edge portions of the copper layer 13 of the multi-layer shim 12 or by edge portions of the metal layer 14 of the multi-layer shim 12.

[0034] FIG. 4 illustrates means to adjust and optimize the noise damping properties of the shim. The figure illustrates a cross-sectional view of a copper layer 17, which may in some embodiments be the copper layer 7 of the first shim 5, the copper layer 11 of the second shim 8, the copper layer 13 of the multi-layer shim 12 or the metal layer 14 of the multi-layer shim 12 described above. The copper layer 17 has been processed in multiple ways to improve the noise damping characteristics of the shim. The copper layer 17 comprises regions with an increased thickness 18, 18′, which may, in some embodiments have a thickness which exceeds an average thickness of the copper layer 17 by more than 10%. In addition, the copper layer 17 comprises through holes 19, 19′ formed by punching to further improve the structural damping characteristics. The through holes 19, 19′ extend through the entirety of the shim. Further, the copper layer 17 comprises micro-slots 20, 20′, which have a width on a micrometer scale and which do not extend through the entire thickness of the copper layer 17. The slots 20, 20′ further improve the structural noise damping characteristics of the shim.

[0035] 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

[0036] 1 Brake disk [0037] 2 Brake pad assembly [0038] 3 Friction layer [0039] 4 Back plate [0040] 5 First shim [0041] 6 Back side of back plate [0042] 7 Copper layer of first shim [0043] 8 Second shim [0044] 9 Resilient tabs [0045] 10 Edge surface of back plate [0046] 11 Copper layer of second shim [0047] 12 Multi-layer shim [0048] 13 Copper layer of multi-layer shim [0049] 14 Metal layer of multi-layer shim [0050] 15 Glue layer of multi-layer shim [0051] 16 Glue layer [0052] 17 Copper layer [0053] 18, 18′ Regions with an increased thickness [0054] 19, 19′ Through holes [0055] 20, 20′ Slots