Abstract
Disclosed is a brake component assembly for a vehicle wheel brake, comprising a first component and a second component, wherein the first and second component are movable relative to one another for engaging and releasing the vehicle wheel brake, wherein a self-lubricating material is provided that is configured to lubricate at least one pair of surfaces that contact one another and that are movable relative to one another when moving the first and second component relative to one another, wherein the self-lubricating material is elastically deformable.
Claims
1. Brake component assembly for a vehicle wheel brake, comprising a first component and a second component, wherein the first and second component are movable relative to one another when engaging and releasing the vehicle wheel brake, wherein a self-lubricating material is provided that is configured to lubricate at least one pair of surfaces that contact one another and that are movable relative to one another when moving the first and second component relative to one another, wherein the self-lubricating material is elastically deformable.
2. Brake component assembly according to claim 1, wherein the self-lubricating material is comprised by a coating arranged at at least one of the surfaces of the pair of surfaces.
3. Brake component assembly according to claim 1, wherein the self-lubricating material is comprised by at least one clip that comprises one of the surfaces of the pair of surfaces and that is held at one of the first component and second component.
4. Brake component assembly according to claim 3, wherein one of the first component and second component is a brake pad and the clip is arranged at the brake pad and is jointly displaceable therewith.
5. Brake component assembly according to claim 3, wherein one of the first component and second component is a brake pad carrier and the clip is arranged at the brake pad carrier.
6. Brake component assembly according to claim 1, wherein the self-lubricating material is provided at both of the surfaces of the pair of surfaces.
7. Brake component assembly according to claim 1, wherein the self-lubricating material is arranged at at least one perforated member that is stiffer than the self-lubricating material, the perforated member comprising or contacting at least one of the surfaces of the pair of surfaces.
8. Brake component assembly according to claim 3, wherein the clip comprises the perforated member and the perforated member comprises a plastic material or a metal material.
9. Brake component assembly according to claim 7, wherein the self-lubricating material is arranged in between a first perforated member and a second perforated member.
10. Brake component assembly according to claim 1, wherein the first component is a brake piston and the second component is a backplate of a brake pad.
11. Brake component assembly according to claim 1, wherein the first component is a finger portion of a brake caliper housing and the second component is a back plate of a brake pad.
12. Brake component assembly according to claim 1, wherein the first component is a guide pin and the second component is a brake pad carrier.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0040] Embodiments of the present disclosure are discussed in the following with reference to the attached schematic drawings. Throughout the figures, same or corresponding features may be marked with same reference signs.
[0041] FIG. 1 shows a vehicle wheel brake according to a prior art example.
[0042] FIG. 2-4 show states of brake component assemblies when activating the vehicle wheel brake according to FIG. 1.
[0043] FIG. 5 shows a brake component assembly according to a first embodiment.
[0044] FIG. 6 shows a brake component assembly according to a second embodiment.
[0045] FIG. 7 shows a brake component assembly according to a third embodiment.
[0046] FIG. 8 shows a clip for a brake component assembly according to a fourth embodiment.
[0047] FIG. 9 shows part of an outer surface of a perforated member of the clip according to FIG. 8.
[0048] FIG. 10 shows a brake component assembly comprising a clip according to a fifth embodiment.
[0049] FIG. 11 shows a brake component assembly comprising a clip according to a sixth embodiment.
[0050] FIG. 12 shows a brake component assembly comprising a clip according to a seventh embodiment.
[0051] FIG. 13 shows a brake component assembly comprising a clip according to an eighth embodiment.
DETAILED DESCRIPTION
[0052] FIG. 1 shows a wheel brake assembly 10 in form of a vehicle disc brake 11, the wheel brake assembly 10 being configured according to generally known floating caliper principles. It comprises a brake caliper housing 12 that is slidingly supported by a stationary brake pad carrier 14.
[0053] The wheel brake assembly 10 is configured to press brake pads 26 (one of which is partially visible in FIG. 1) against a brake disc 16. The brake pads 26 are received in and guided by the brake pad carrier 14. Only part of an outer circumferential edge of the brake disc 16 is indicated by a dashed line in FIG. 1, the brake disc 16 generally being configured according to known examples. Further, a rotation axis R about which the brake disc 16 rotates is schematically indicated by a dotted line in FIG. 1.
[0054] The brake caliper housing 12 comprises a receiving section 15. Only an outer wall of said receiving section 15 is visible in FIG. 1 and the receiving section 15 is formed as an (non-visible) open cylindrical cavity. In said receiving section 15, a non-illustrated brake piston is received.
[0055] The brake caliper housing 12 comprises a piston side 18 located at a first side face of the brake disc 16 and specifically at the same side face as the receiving section 15. Further, the brake caliper housing 12 comprises a finger side 20 located at the respective opposite side face of the brake disc 16 compared to the piston side 18. The finger side 20 comprises (merely as an example) two finger portions 21 according to known configurations.
[0056] The finger side 20 and the piston side 18 are connected to one another by a bridge section 22. The bridge section 22 overlaps with the outer circumferential surface of brake disc 16 or, put differently, axially spans across the brake disc 16 and/or extends from one of the side faces of said brake disc 16 to the other.
[0057] In a generally known manner, the brake piston received in the receiving section 15 and the inside of the finger portions 21 that face away from the viewer in FIG. 2 are configured to rest against the brake pads 26 and to press them against the brake disc 16.
[0058] Just like the brake caliper housing 12, the brake pad carrier 14 comprises a piston side 18, a finger side 20 and a bridge section 22. Guiding grooves 24 of the brake pad carrier 14 are provided at an inner side of the bridge section 22 for slidingly receiving the two brake pads 26, one of said guiding grooves 24 being partially visible in FIG. 1. The brake pads 26 are located on opposite side faces of the brake disc 16. The brake pads 26 are generally identical to one another, but are oriented differently to face the different side faces of the brake disc 16.
[0059] Each brake pad 26 comprises guiding projections 23, one of which is visible in FIG. 1. Each guiding projection 23 is received in one of the guiding grooves 24. Pad springs 25 that are configured as bent sheet metal parts are arranged in between each guiding groove 24 and each guiding projection 23, so that the guiding projections 23 do not directly contact the guiding grooves 24, but the pad spring 25 instead.
[0060] FIG. 1 also illustrates that the movable brake caliper housing 12 is slidingly supported by and guided relative to the brake pad carrier 14 by means of guide pins 28. These are provided at both of a trailing side and leading side of the wheel brake assembly 10.
[0061] According to the configuration of FIG. 1, the guide pins 28 are each received in a non-illustrated cylindrical blind hole in the brake pad carrier 14. An axial length of said blind holes exceeds that of the guide pins 28, so that the latter may axially slide back and forth within the blind holes.
[0062] The guide pins 28 are secured to the brake caliper housing 12 by means of a screw connection. Specifically, fixing projections 31 are provided at each of a trailing side and a leading side of the brake caliper housing 12, said fixing projections 31 each comprising a non-visible through-hole. A guide pin 28 is aligned with each of said through holes to engage with a locknut 33 provided at an opposite side of the fixing projections 31. This way, the guide pins 28 are mechanically fixed to the fixing projections 31 and thus to the brake caliper housing 12.
[0063] FIGS. 2-4 show different states of relative orientations of a guiding projection 23 of one of the brake pads and a guiding groove 24 formed in the brake pad carrier 14 during different stages of a braking operation. These figures are highly schematic and only part of the guiding projection 23 and brake pad carrier 14 are depicted (as indicated by dashed lines). The guiding projection 23 is mirror symmetric with respect to a plane of symmetry S, so as to have a rectangular shape. This is more clearly visible from the below FIGS. 10-13 showing a guiding projection 23 in full. Similarly, the recess 24 actually has a rectangular outline that is open to one side for receiving the guiding projection 23. This is also more clearly visible from the below FIGS. 10-13.
[0064] For the purpose of illustration, the pad spring 25 is not shown in FIGS. 2-4 but may be provided in between and separate the brake pad carrier 14 and guiding projection 23.
[0065] FIG. 2 illustrates a state in which the brake is not active and the brake pad 26 is not actively displaced by a brake piston provided in the receiving section 15. Thus, there may be a significant clearance between the guiding projection 23 and brake pad carrier 14 that e.g. accommodates the non-illustrated the pad spring 25.
[0066] FIG. 3 illustrates a state in which the brake pad 26 is pressed by the brake piston against the brake disc 16. In this case, the clearance between the guiding projection 23 and the brake pad carrier 14 is at least locally reduced. In particular, these members are forced towards one another in at least one defined direction. Accordingly, the non-depicted pad spring 25 is clamped in between these members 23, 14 in substantially one defined area.
[0067] FIG. 4 shows a state in which the brake force is released. The guiding projection 23 may thus abruptly change its orientation due to the released tension. Therefore, undefined contacts to surrounding surfaces (e.g. of the non-illustrated pad spring 25) and/or undefined areas of compression of the pad spring 25 may occur. This may result in flutter vibrations discussed above.
[0068] FIGS. 5-7 show embodiments of a brake component assembly 34 according to embodiments of this disclosure. The brake component assembly 34 may generally be provided in a wheel brake assembly 10 similar to FIG. 1, but with the additional specifics according to the presently disclosed invention as discussed in the following. Again, a pad spring 25 as in FIG. 1 may optionally be provided, but is not illustrated in FIG. 5.
[0069] The brake component assembly 34 comprises as a first component 36 the brake pad 26 and as a second component 38 of the brake pad carrier 14 and especially a guiding projection 23 comprised thereby. Similar to FIGS. 2-4, only parts of these components are shown. A plane of symmetry S is indicated, similar to FIG. 2.
[0070] FIG. 5 shows that the brake component assembly 34 also comprises a self-lubricating material 40. This self-lubricating material 40 may be configured according to any of the examples disclosed herein, in particular as a self-lubricating elastomer, such as a silicone material. The self-lubricating material 40 is provided in form of a coating. This coating is applied to outer surfaces of the guiding projection 23 which face surfaces of the guiding recess 24. An extension of the coating (i.e. of the self-lubricating material 40) beyond the plane of symmetry is illustrated by dashed lines in FIG. 5.
[0071] Accordingly, the self-lubricating material 40 comprises a first surface 42 that is configured to contact a second surface 44 comprised by the guiding recess 24, the first surface 42 and the second surface 44 forming a pair of surfaces 46 that may contact one another. Another respective pair of surfaces 46 may be formed by the (in FIG. 5) upper and lower horizontal surfaces of the self-lubricating material 40 and a respectively opposite surface of the guiding recess 24. In these cases, however, no dedicated reference signs are included in FIG. 5.
[0072] The self-lubricating material 40 is elastically deformable by contact forces occurring during normal brake operation, e.g. during normal brake activation or brake release. In particular, the self-lubricating material 40 may be elastically deformable under the weight of any of the components 36, 38 of the brake component assembly 34. For example, the elastic deformation during brake operation may include a compressibility in at least one dimension of the self-lubricating material 40 (e.g. a thickness dimension) of at least 5%.
[0073] By coating those surfaces of the guiding projection 23 that may potentially contact the guiding recess 24 (or a non-illustrated optional pad spring 25) with the self-lubricating material 40, contact forces between these members may at least partially be dampened by an elastic deformation of the self-lubricating material 40. Also, these surfaces are self-lubricated to limit friction and thereby uncontrolled relative movements of the components 36, 38. As a result, the elastic deformation in combination with the self-lubrication help to limit vibrations and acoustic noises, especially during the above-discussed releasing stage according to FIG. 4.
[0074] FIG. 6 illustrates another embodiment in which, contrary to the embodiment of FIG. 5, the self-lubricating material 40 is provided at the guiding recess 24. Specifically, it is provided at all surfaces of said guiding recess 24 that may potentially contact the guiding projection 23. This provides similar effect as in case of FIG. 5.
[0075] FIG. 7 illustrates another embodiment in which the embodiments of FIGS. 5 and 6 are combined. Specifically, in this case outer surfaces of both the guiding projection 23 and guiding recess 24 are coated with the self-lubricating material 40.
[0076] It is to be noted that the present disclosure is not limited to the brake component assembly 34 comprising the specific first and second components 36, 38 of FIGS. 5 to 7. Any other component combinations as disclosed herein may be provided. In these other component combinations, any or both of the components 36, 38 may equally be coated with a self-lubricating material 40.
[0077] Further, in case of FIGS. 5-7, the surfaces 42, 44 of the pair of surfaces 46 that contact and move relative to one another are directly comprised by the first and second components 36, 38.
[0078] FIGS. 8 to 13 contain further embodiments according to this disclosure in which, additionally or alternatively to the embodiments of FIGS. 5 to 7, the self-lubricating material 36 is comprised by a separate member. This separate member is a clip 48 that is arrangeable in between the first and second components 36, 38 of a brake component assembly 34. Specifically, this clip 48 is fixed to one of the components 36, 38 of a brake component assembly 10. It may comprise at least one surface 42, 44 of a pair of surfaces 46 that are movable relative to one another when activating or releasing the brake, similar to the pair of surfaces 46 in FIG. 5.
[0079] In FIG. 8, a cross-section through a clip 48 as e.g. comprised by a brake component assembly 10 of FIG. 10 is shown. The clip 48 has a C-shape with the depicted orientation resembling a reversed or mirrored orientation of said C-shape. The clip 48 comprises an inner perforated member 50 and an outer perforated member 54 that are each shaped according to the C-shaped. The inner and outer perforated members 50, 54 are both made of a rigid metallic material. They each comprise a number of through-holes 52 forming the perforations and extending through or across the respective thicknesses or, put differently, material strengths. Not all of the through-holes 52 are marked with an own reference sign in FIGS. 8 and 9. The through-holes 52 open towards outer external surfaces (see outer perforated member 54 in FIG. 8) and inner external surfaces (see inner perforated member 50 in FIG. 8).
[0080] A layer of self-lubricating material 40 is arranged in between and is thus sandwiched between the perforated members 50, 54. A lubricant that is exuded by said self-lubricating material 40 can thus be released through the through holes 52 towards the respective inner and outer external surfaces of the clip 48. This may e.g. occur when the self-lubricating material 40 is exposed to mechanical pressure and/or may occur steadily over time.
[0081] Merely as an example, the outer perforated member 54 may be thicker (i.e. have a larger material strength) than the inner perforated member 50.
[0082] Alternatively, these members may have a substantially similar thickness. A thickness of the self-lubricating material 40 may be lower than a thickness of any of the inner and outer perforated members 50, 54. For example, the outer perforated member 54 may have a thickness of 0.3 mm to 0.5 mm and/or the inner perforated member 50 may have a thickness of 0.2 mm to 0.3 mm. The layer of self-lubricating material 40 may have a thickness of 0.1 to 0.2 mm. Generally, any of the inner perforated member 50, outer perforated member 54 and self-lubricating material 40 may have a thickness of less than 1 mm and e.g. not more than 0.5 mm. A thickness dimension T is marked for the outer perforated member 54 in FIG. 8 and is correspondingly oriented for the inner perforated member 50 and self-lubricating material 40.
[0083] Due to being arranged in between the perforated members 50, 54, the self-lubricating material 40 provides an elastic deformability of the overall clip 48. Specifically, the self-lubricating material 40 acts as an elastically deformable spacer that is arranged in between the perforated members 50, 54.
[0084] FIG. 9 is a frontal view of an externally facing surface section of any of the perforated members 50, 54. In this Figure, the openings of the through holes 52 face the viewer. Again, only some of said through holes 52 are provided with an own reference sign.
[0085] FIG. 10 illustrates and arrangement of the clip 48 of FIG. 8 within a brake component assembly 10 according to an embodiment of this disclosure. The clip 48 is schematically illustrated and does not show all details of the cross-section of FIG. 8.
[0086] The brake component assembly 10 of FIG. 10 again comprises a first component 36 in form of a brake pad 26 and a second component 38 in form of a brake pad carrier 14. The clip 48 is held at and is jointly movable with the brake pad 26, but could alternatively be held at the brake pad carrier 14.
[0087] It may be beneficial to provide self-lubrication in between the clip 48 and the respective one of the brake pad 26 and brake pad carrier 14 at which the clip 48 is held. This is because small relative movements and in particular vibrations may still occur between these members. In the shown example, the clip 48 is connected to the brake pad 26 by a force fit resulting from an elastic deformation when pushing the clip 48 onto the guiding projection 23.
[0088] In FIG. 10, a pair of surfaces 46 that are movable relative to one another by a substantial distance of several millimetres or centimetres when operating the vehicle wheel brake 11 comprise: a first surface 42 which is in outer surface of the clip 48 and a second surface 44 which is an inner surface of the guiding recess 42. These surfaces 42, 44 are lubricated by way of the self-lubricating material 40 of FIG. 8. This material releases a lubricant that reaches an outer surface of the outer perforated member 54 of FIG. 8.
[0089] For the sake of completeness, FIG. 10 shows a position of a horizontal plane of symmetry S mentioned earlier in connection with FIG. 5. Also, another vertical plane of symmetry S is shown and the brake pad 26 is mirror-symmetric with respect to this vertical plane of symmetry S. Accordingly, a second non-illustrated guiding projection 23 is provided comprising a similar clip 48.
[0090] FIG. 11 is a development of the embodiment of FIG. 10 and additionally indicates positions of fixing the clip 48 to the guiding projection 23 by locally deposited volumes of adhesive 56. In this case, the clip 48 may be configured according to FIG. 8 or may only comprise the outer perforated member 54 of FIG. 8, but not the inner perforated member 50.
[0091] FIG. 12 shows another example similar to FIG. 11, but with the adhesive 56 being provided as a larger and preferably continuous layer. Specifically, an inner surface of the clip 48 can be largely or even fully coated with the adhesive 56 to be secured at the guiding projection 23. Again, in this case the inner perforated member 50 of FIG. 8 may be omitted.
[0092] FIG. 13 as a configuration similar to FIG. 12 but with the clip 48 having a slightly different form. Specifically, instead of the C-shape of FIG. 12 having sharp edges and thus resembling a rectangular shape with one open side, the clip 48 has a more rounded C-shape. Optionally, its rounded section may be arranged at a distance to a respectively adjacent surface of the guiding projection 23. Thus, the rounded section may provide a spring-like deformable section. A direction of deformability may extend in a (in FIG. 13 horizontal) direction extending orthogonally to the depicted vertical plane of symmetry S. Again, the clip 48 may have no inner perforated member 50 as depicted in FIG. 8.
[0093] It is noted that a clip 48 as shown throughout the FIGS. 8 to 13 can be provided instead of a known pad spring 25 according to the prior art solution of FIG. 1. Specifically, the clip 48 may comprise a non-illustrated elastically deformable portion similar to known pad springs 25 to provide a restoring effect (i.e. for moving the brake pad 26 reliably into its inactive position when releasing the brake).
[0094] It is also noted that the use of perforated members 50, 54 of e.g. FIG. 8 is not limited to the embodiment comprising a clip 48. Rather, a perforated member 50, 54 at which a layer of self-lubricating material 40 is provided can also be used to replace known shims at back plate of a brake pad 26. Also, perforated members 50, 54 may be used in between any types of first and second components 36, 38 disclosed herein, wherein said types may be different from a brake pad 26 and brake pad carrier 14.
