Abstract
A fastener for fixing a brake disk to a wheel hub includes a shaft, a head formed on an end of the shaft, or a counterpart configured for being coupled to the shaft, and at least one damping member integrated into the shaft and/or disposed on a surface of the head or the counterpart.
Claims
1. A fastener for fixing a brake disk to a wheel hub, comprising: a shaft; a head formed on an end of the shaft or a counterpart configured for being coupled to the shaft; and at least one damping member integrated into the shaft and/or disposed on a surface of the head or the counterpart.
2. The fastener of claim 1, wherein the shaft comprises a central recess extending along a central axis of the shaft, wherein the damping member is disposed in the central recess.
3. The fastener of claim 2, wherein an inner diameter of the central recess lies in a range of 10% to 70% of an outer diameter of the shaft.
4. The fastener of claim 1, wherein the shaft comprises an annular recess surrounding and extending along a central axis of the shaft, wherein the damping member is disposed in the annular recess.
5. The fastener of claim 1, wherein the shaft comprises plural recesses extending along a central axis of the shaft, wherein one damping member is disposed in each of the plural recesses.
6. The fastener of claim 1, wherein the head or the counterpart comprises a contact surface at least partially surrounding the shaft and being oriented along a central axis of the shaft, wherein the damping member is disposed on the contact surface.
7. The fastener of claim 6, wherein the damping member has a thickness in a range between 0.5 mm and 5 mm.
8. The fastener of claim 1, wherein the damping member is made of a material having a dissipation factor greater or equal than 0.5%, preferably greater or equal than 1%, particularly preferably greater or equal than 3%.
9. The fastener of claim 1, wherein the damping member is made of an elastomer material, a thermoplastic or a duroplast material, or cast iron.
10. The fastener of claim 1, wherein the shaft and the head or the counterpart are made of a metal material.
11. The fastener of claim 1, wherein the shaft comprises an external thread.
12. The fastener of claim 1, wherein the counterpart is a nut or a sleeve.
13. An axle assembly for a vehicle, comprising: a wheel hub comprising plural attachment openings; a brake disk comprising plural through holes positioned aligned with the attachment openings of the wheel hub; and plural fasteners according to claim 1 fastening the brake disk to the wheel hub, wherein each fastener extends with its shaft through one of the attachment openings of the brake disk and into one of the attachment openings of the wheel hub, and with its head or counterpart abuts against the brake disk.
14. The axle assembly of claim 13, further comprising: a knuckle; and a brake caliper mounted to the knuckle, the brake caliper comprising a friction pad movable into contact with the brake disk to apply a friction braking force to the brake disk.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] For a more complete understanding of the present invention and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings. The invention is explained in more detail below using exemplary embodiments, which are specified in the schematic figures of the drawings, in which:
[0036] FIG. 1 schematically illustrates a plan view of an axle assembly according to an embodiment of the invention.
[0037] FIG. 2 schematically illustrates cross-sectional partial view of an axle assembly according to an embodiment of the invention.
[0038] FIG. 3 schematically illustrates a further cross-sectional partial view of an axle assembly according to an embodiment of the invention.
[0039] FIG. 4 schematically illustrates a cross-sectional view of a fastener according to an embodiment of the invention.
[0040] FIG. 5 schematically illustrates a cross-sectional view of a fastener according to a further embodiment of the invention.
[0041] FIG. 6(A) schematically illustrates a cross-sectional view of a fastener according to a further embodiment of the invention.
[0042] FIG. 6(B) schematically illustrates a plan view to the second end of the shaft of the fastener according to a further embodiment of the invention.
[0043] FIG. 7(A) schematically illustrates a cross-sectional view of a fastener according to a further embodiment of the invention.
[0044] FIG. 7(B) schematically illustrates a plan view to the second end of the shaft of the fastener according to a further embodiment of the invention.
[0045] FIG. 8 schematically illustrates a cross-sectional view of a fastener according to a further embodiment of the invention.
[0046] FIG. 9 schematically illustrates a cross-sectional view of a fastener according to a further embodiment of the invention.
[0047] FIG. 10 schematically illustrates a cross-sectional view of a fastener according to a further embodiment of the invention.
[0048] In the figures like reference signs denote like elements unless stated otherwise.
DETAILED DESCRIPTION OF EMBODIMENTS
[0049] FIG. 1 schematically shows a plan view of an axle assembly 100 for a vehicle. FIG. 2 shows a partial cross-sectional view of the axle assembly 100 in the region of a wheel hub 110, and FIG. 3 shows a further partial cross-sectional view of the axle assembly 100 in the region of a brake caliper 140. The axle assembly 100 may be employed, for example, in an automobile, a bus, a lorry, a motorcycle or similar.
[0050] As schematically shown in FIGS. 1 to 3, the axle assembly 100 comprises a wheel hub 110, a brake disk 120, a knuckle 130, and a brake caliper 140. The brake disk 120 and the brake caliper 140, together, form a friction brake, in particular, a disk brake. The wheel hub 110 and the knuckle 130 form an axle.
[0051] The wheel hub 110 is only schematically shown in FIG. 2 and may include a central body 114, which may, for example, by a cylindrical or polygonal shaft, and a collar 116 protruding from a circumferential surface 114c of the rim 116. The collar 116 may include a contact surface 116a.
[0052] The wheel hub 110 may be rotatably mounted to the knuckle 130, e.g., by means of a bearing 135, as schematically shown in FIG. 2. Generally, the wheel hub 110 may be mounted to be rotatable about a rotational axis A100. The rotational axis A100 may be defined by the bearing 135. The contact surface 116a of the rim 116a may be oriented along the rotational axis A100.
[0053] The wheel hub 110 comprises a plurality of attachment holes 112. In FIG. 2, for the sake of clarity, only one single attachment hole 112 is shown. The attachment holes 112, for example, may be formed in the central body 114 of the wheel hub 110, as exemplarily shown in FIG. 2. However, the invention is not limited to this configuration.
[0054] The brake disk 120, generally, may be a disk shaped part and comprises oppositely oriented friction surfaces 121a, 121b. As exemplarily and only schematically shown in FIGS. 1 and 2, the disk 120 may comprise a disk body 121 and a disk cup 123. The disk body 121 may comprise the friction surfaces 121a, 121b and being formed as ring. The disk cup 123 may be arranged in a central opening of the ring shaped disk body 121 and being connected to the disk body 121, as schematically shown in FIG. 2. For example, the disk body 121 and the disk cup 123 may be material joined, e.g., by welding or similar. As exemplarily shown in FIG. 2, the cup 123 may comprise a plate shaped base member 124, and a centering wall 125 protruding from the base member 125 and defining a closed frame or circumferential wall. The centering wall 125 and the base member 124, together, define a receiving cavity.
[0055] The brake disk 120 further comprises a plurality of through holes 122. As exemplarily shown in FIGS. 1 and 2, the through holes 122 may be formed in the disk cup 123, in particular, in the base member 124 of the disk cup 123. However, the invention is not limited to this configuration.
[0056] As schematically shown in FIG. 2, the disk 120 is attached to the wheel hub 110 by means of fasteners 1 which will be described in more detail below. The disk 120 is positioned on the wheel hub 110 such that the through holes 122 of the disk 120 are aligned with the attachment openings 112 of the wheel hub 110. As exemplarily and schematically shown in FIG. 2, the central body 114 of the wheel hub 110 may protrude into the receiving opening of the disk cup 123, wherein an end face 114a of the central body 114 may contact the base member 124 of the cup 123. Additionally or alternatively, the circumferential surface 114c of the central body 114 of the wheel hub 110 may be in contact with an inner circumferential surface of the circumferential wall 125 of the cup 123. Further optionally, the brake disk 120 may abut against the contact surface 116a of the optional collar 116.
[0057] The brake caliper 140 is shown with some details in FIG. 3 in a simplified manner. As shown in FIG. 3, the brake caliper 140 comprises a carrier 142, a pair of friction pads 141, and at least one actuator 144. As further shown in FIG. 3, the carrier 142 defines a passage 143 through which the disk 120, in particular, the disk body 121 extends. The friction pads 141 are positioned on opposite sides of the passage 143 and are coupled to the carrier 142, for example, via respective clips (not shown). Generally, at least one of the friction pads 141 is coupled to the carrier 142 such that it is movable by the actuator 144 along an axial direction to come into contact with the friction surface 120a, 120b of the disk 120. The axial direction extends parallel to the rotational axis A100 of the wheel hub 110. The actuator 144, as exemplarily shown in FIG. 3, may be a hydraulic piston. For example, the actuator may be coupled to a hydraulic line which is connected to a main brake cylinder (not shown). The main brake cylinder may be actuated by a pedal or a lever, optionally, in concert with a brake force booster.
[0058] In the example of FIG. 3, the carrier 142 is mounted to the knuckle 130 so as to be movable along the axial direction. Thereby, if the actuator 144 moves the one friction pad 142 into contact with the friction surface 121b of the disk 120, an axial displacement of the carrier 142 takes place which moves the other friction pad 141 into contact with the opposite friction surface 121a of the disk 120. Consequently, a frictional force between the friction pads 141 and the disk 120 is generated which brakes the disk 120.
[0059] FIGS. 4 to 10 show in detail examples of fasteners 1 for the brake disk 120 to the wheel hub 110. As visible in FIGS. 4 to 10, a fastener 1 comprises a shaft 10, a head 13 or, alternatively, a counterpart 14 (FIG. 10), and at least one damping member 16.
[0060] The shaft 10, generally, extends between a first end 11 and a second end 12 and defines a central axis A10. For example, the shaft 10 may be a generally cylindrical part. As further schematically shown in FIGS. 4 to 10, the shaft 10, optionally, may comprise an external thread 18. The shaft 10 may have an outer diameter d10 that may be adapted to the braking moments applied to the disk 120 and the number of fasteners 1 used to fix the disk 120 to the hub 110. For example, the outer diameter d10 may lie in a range between 6 mm and 20 mm. The shaft 10 may be made of a metal material, e.g., steel.
[0061] FIGS. 4 to 9, exemplarily, show fasteners 1 having a head 13. The head 13 is formed on the first end 11 of the shaft 10. The head 13, generally, protrudes from the outer circumference of the shaft 10. For example, a diameter d13 may be greater than the outer diameter d10 of the shaft 10. The head 13 comprises a contact surface 13a which is oriented along the central axis A10 of the shaft 10. The contact surface 13a, thus, faces towards the second end 12 of the shaft 10. The head 13, for example, may be integrally formed with the shaft 10. Optionally, the head 13 may be made of a metal material, e.g., steel.
[0062] FIG. 10 exemplarily shows a fastener 1 comprising a counterpart 14 instead of a head 13. The counterpart 14, for example, may be nut or a sleeve. Generally, the counterpart 14 is configured for being coupled to the shaft 10. For example, the counterpart 14 may be provided with an inner thread (not shown) that is configured to be screwed to the external thread 18 of the shaft 10. However, also other types of connection between the counterpart 14 and the shaft 10 are possible. As visible in FIG. 10, when being coupled to the shaft 10, the counterpart 14 also protrudes from the circumference of the shaft 10. For example, the counterpart 14 may have an outer diameter d14 greater than the outer diameter d10 of the shaft 10. The counterpart 14, similar as the head 13, may comprise a contact surface 14a. As shown in FIG. 10, the contact surface 14a is oriented along the central axis A10 and, thus, may face towards the second end 12 of the shaft 10, when the counterpart 14 is coupled to the shaft 10. The counterpart 14 may be made of a metal material such as, e.g., steel.
[0063] The at least one damping member 16, generally, is configured to absorb or dampen vibrations. For example, the damping member 16 may be made of a material having a dissipation factor greater or equal than 0.5%, optionally greater or equal than 1%, further optionally greater or equal than 3%. For example, the damping member 16 may be made of elastomer material, a thermoplastic or a duroplast material, or cast iron.
[0064] As schematically shown in FIGS. 5 to 7, 9 and 10, one or more damping members 16 may be integrated into the shaft 10 of the fastener 1. In general, the damping member 16, in this case, is integrated into or disposed within the cross-section of the shaft 10 and, preferably, is not disposed to the outer circumferential surface of the shaft 10.
[0065] For example, as schematically shown in FIGS. 4 and 5, the shaft 10 may comprise a central recess 15 extending along the central axis A10 of the shaft 10, and the damping member 16 may be disposed in the central recess 15. As visible in FIGS. 4 and 5, the central recess 15 may be coaxial to the central axis A10. The central recess 15 may, for example, have circular or polygonal cross-section but the invention is not limited to these cross-sectional shapes. An inner diameter d15 of the central recess 15 may lie, for example, in a range of 10% to 70% of the outer diameter d10 of the shaft 10. FIG. 4 schematically shows a fastener 1 in which the central recess 15 has an inner diameter d15 which is about 10% of the outer diameter d10 of the shaft 10. FIG. 5 schematically shows a fastener 1 in which the central recess 15 has an inner diameter d15 which is about 70% of the outer diameter d10 of the shaft 10. The central recess 15 may extend over the complete length of the shaft 10 between the first and the second end 11, 12, as exemplarily shown in FIGS. 4 and 5. Alternatively, it is also possible that the central recess 15 only extends over a part of the length of the shaft 10 and ends distanced to the first end 11 of the shaft 10. Generally, it may be provided that the central recess 15 extends over at least 50% of the length of the shaft 10 measured between the first and second end 11, 12.
[0066] The damping member 16 may have a cross-section that corresponds to the cross-section of the central recess 15 and completely fills the central recess 15. The damping member 16 may, for example, be joined to the inner circumferential surface of the central recess 15. For example, the damping member 16 may be filled into the recess 15 in a liquid state and cured or solidified in the recess 15.
[0067] FIG. 6 exemplarily and schematically shows a fastener 1 in which the damping element 16 is integrated into the shaft 10 in an annular recess 17. In FIG. 6, view (A) shows a cross-sectional view of the fastener 1, and view (B) shows a plan view to the second end 12 of the shaft 10 of the fastener 1. As shown in FIG. 6, the shaft 10 may comprise an annular recess 17 surrounding and extending along the central axis A10 of the shaft 10. While FIG. 6 in view (B) shows that the annular recess 17 may have a circular shape, the invention is not limited to an annular recess 17 having circular shape but may also be in the form of a rectangle, a triangle, a hexagon or other closed annulus. The annular recess 17 may extend over the complete length of the shaft 10 between the first and the second end 11, 12, as exemplarily shown in FIG. 6. Alternatively, it is also possible that the annular recess 17 only extends over a part of the length of the shaft 10 and ends distanced to the first end 11 of the shaft 10. Generally, it may be provided that the annular recess 17 extends over at least 50% of the length of the shaft 10 measured between the first and second end 11, 12.
[0068] The damping member 16 may have a cross-section corresponding to the cross-section of the annular recess 17 and is disposed in the annular recess 17. The damping member 16, thus, completely fills the central recess 15. The damping member 16 may, for example, be joined to the inner and outer circumferential surfaces of the annular recess 17. For example, the damping member 16 may be filled into the recess 17 in a liquid state and cured or solidified in the recess 17.
[0069] FIG. 7 exemplarily and schematically shows a fastener 1 in which multiple damping element 16 are integrated into the shaft 10 in a plurality of recesses 15A. In FIG. 7, view (A) shows a cross-sectional view of the fastener 1, and view (B) shows a plan view to the second end 12 of the shaft 10 of the fastener 1. As shown in FIG. 7, the shaft 10 may comprise multiple recesses 15A extending along the central axis A10 of the shaft 10. As exemplarily shown in view (B) of FIG. 7, the recesses 15A, for example, may have circular cross-section. However, the invention is not limited to circular cross-sections. As further exemplarily shown in FIG. 7, the recesses 15A may be arranged around the central axis A10 of the shaft 10. Further optionally, the recesses 15A may be equally distanced to each other along the circumference of the shaft 10. As visible in view (A) of FIG. 7, the recesses 15A all may have the same length. However, it may also be provided that at least some of the recesses 15A have different lengths. The recesses 15A, optionally, may extend over the complete length of the shaft 10 between the first and the second end 11, 12, as exemplarily shown in FIG. 7. Alternatively, it is also possible that the recesses 15A only extend over a part of the length of the shaft 10 and end distanced to the first end 11 of the shaft 10. Generally, it may be provided that the recesses 15A extend over at least 50% of the length of the shaft 10 measured between the first and second end 11, 12.
[0070] As shown in FIG. 7, one damping member 16 may be provided for each of the recesses 15A. The damping members 16 may have a cross-section that corresponds to the cross-section of the respective recess 15A and completely fill the respective recess 15. The damping members 16 may, for example, be joined to the inner circumferential surfaces of the recesses 15A. For example, the damping member 16 may be filled into the recesses 15A in a liquid state and cured or solidified in the recess 15.
[0071] It should be noted that multiple damping members 16 may be integrated into the shaft 10 by combining any one of the examples shown in FIGS. 4 to 7.
[0072] As exemplarily shown in FIG. 8, it is also possible to dispose a damping member 16 on a surface of the head 13. For example, a damping member 16 may be disposed on the contact surface 13a of the head 13. As schematically shown in FIG. 8, it may be provided that the damping member 16 is formed on the contact surface 13a so as to completely surround the circumference of the shaft 10. Alternatively, it would also be possible to arrange multiple damping members 16 on the contact surface 13a spaced to each other along the circumference of the shaft 10. A thickness t16 of the damping member 16, in this case, may lie in a range between 0.5 mm and 5 mm, for example. The damping member 16 may be joined to the contact surface 13a, e.g., by an adhesive, by welding, or by another material joining method.
[0073] FIG. 9, by way of example only, shows a fastener 1 in which a damping element 13 is disposed on the contact surface 13a of the head 13, and a further damping element 13 is disposed in a central recess 15 of the shaft 10. Of course, instead of a central recess 15, it would also be possible to provide any types of recesses 15, 15A, 17 as described above by reference to FIGS. 4 to 7 or any combinations thereof.
[0074] In the fastener 1 exemplarily shown in FIG. 10, the damping member 16 is disposed on the contact surface 14a of the counterpart 14. As schematically shown in FIG. 9, it may be provided that the damping member 16 is formed about entire circumference of the counterpart 14 so that, when the counterpart 14 is coupled to the shaft 10, the contact surface 14a completely surrounds the circumference of the shaft 10. Alternatively, it would also be possible to arrange multiple damping members 16 on the contact surface 14a spaced to each other along the circumference of the counterpart 14. A thickness t16 of the damping member 16, in this case, may lie in a range between 0.5 mm and 5 mm, for example. The damping member 16 may be joined to the contact surface 14a, e.g., by an adhesive, by welding, or by another material joining method.
[0075] Referring again to FIG. 2, to fix the brake disk 120 to the wheel hub 110, each fastener 1 with its shaft 1 extends through one of the attachment openings 122 of the brake disk 120 and into one of the attachment openings 112 of the wheel hub 110. For example, the shaft 10 may be fixed in the attachment opening 112, e.g., in that the external thread 18 is screwed to an internal thread (not shown) of the attachment opening 112. Further, each fastener 1 with its head 13 or counterpart 14 abuts against the brake disk 120, e.g., against the base member 124 of the disk cup 123. Thereby, the disk 120, i.e., the disk cup 123, is clamped between the head 13 or counterpart 14 and the hub 110, i.e., the end face 114a of the central body 114 of the hub 110.
[0076] Since the fasteners 1 include the damping member 16, vibrations occurring in the disk 120, e.g., due to relative motion between the friction pads 141 and the disk 120 during braking, or occurring in the axle are at least partially absorbed in the damping member 16 which is arranged in the force flow path between the hub 110 and the disk 120. Consequently, mutual excitation of the disk 120 and the hub 110 or, generally, the axle is inhibited Thereby, occurrence of acoustic noise can be reduced.
[0077] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of at least ordinary skill in the art that a variety of alternate and/or equivalent implementations exist. It should be appreciated that the exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.
