BRAKE ASSEMBLY AND METHOD FOR OPERATING A BRAKE ASSEMBLY FOR A VEHICLE WHEEL

Abstract

A brake assembly includes a braked member that is coupable or coupled to the vehicle wheel for a joint rotation therewith about a rotational axis, the braked member having contact surfaces that are arranged at an axial distance from one another and a braking unit that comprises a brake force generator and at least two brake pads, the brake pads being positioned in between the contact surfaces, wherein the brake force generator is configured move the brake pads axially apart from one another, thereby bringing each brake pad into contact with one of the contact surfaces of the braked member.

Claims

1. A brake assembly for a vehicle wheel, the brake assembly comprising: a braked member that is coupable or coupled to the vehicle wheel for a joint rotation therewith about a rotational axis, the braked member having contact surfaces that are arranged at an axial distance from one another; and a braking unit that comprises a brake force generator and at least two brake pads, the brake pads being positioned in between the contact surfaces, wherein the brake force generator is configured move the brake pads axially apart from one another, thereby bringing each brake pad into contact with one of the contact surfaces of the braked member.

2. The brake assembly according to claim 1, wherein the contact surfaces face each other.

3. The brake assembly according to claim 1, wherein the contact surfaces form at least part of opposite side faces of a space in which the brake pads are at least partially received.

4. The brake assembly according to claim 3, wherein a brake dust collector is arranged within said space, in particular at a bottom face that extends in between the contact surfaces.

5. The brake assembly according to claim 1, wherein the brake pads are movable apart from one another along an axis extending in parallel to the rotational axis (R).

6. The brake assembly according to claim 1, wherein the contact surfaces are each comprised by brake disc portions of the braked member.

7. The brake assembly according to claim 6, wherein the brake disc portions extend in parallel to one another, in particular wherein the brake disc portions each extend orthogonally to the rotational axis (R) of the braked member.

8. The brake assembly according to claim 1, wherein at least one of the brake disc portions comprises a stiffening structure at a side thereof that is opposite to the side comprising the contact surface of the at least one brake disc portion.

9. The brake assembly according to claim 1, wherein each of the brake pads is displaceable relative to a housing of the braking unit and relative to one another.

10. The brake assembly according to claim 1, wherein the brake force generator comprises one of an electric actuator and a hydraulic chamber, each of which being configured to generate the force for moving both of the brake pads.

11. The brake assembly according to claim 10, wherein at least part of the electric actuator or hydraulic chamber are received in the space.

12. The brake assembly according to claim 1, comprising at least one further brake pad that can be brought into contact with a further contact surface facing away from at least one of the other contact surfaces.

13. A method of operating a brake pad assembly, the brake pad assembly comprising: a braked member that is coupable or coupled to the vehicle wheel for a joint rotation therewith about a rotational axis (R), the braked member having contact surfaces that are arranged at an axial distance from one another; and a braking unit that comprises at least two brake pads, the brake pads being positioned in between the contact surfaces, wherein the method comprises: moving the brake pads axially apart from one another, thereby bringing each brake pad into contact with one of the contact surfaces of the braked member.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0053] FIG. 1 is a cross-sectional view of a brake disc assembly according to a first embodiment of the invention.

[0054] FIG. 2 is a cross-sectional view of a brake disc assembly according to a second embodiment of the invention.

[0055] FIG. 3 is a cross-sectional view of a brake disc assembly according to a third embodiment of the invention.

[0056] FIG. 4 is a cross-sectional view of a brake disc assembly according to a fourth embodiment of the invention.

DETAILED DESCRIPTION

[0057] In FIG. 1, a cross-sectional view of a brake assembly 10 according to an embodiment of the invention is shown. The brake assembly 10 is provided for braking a vehicle wheel whose position is indicated by reference sign 1. Accordingly, the vehicle wheel is positioned axially next to the brake assembly 10. The vehicle wheel rotates about an axis R. The cross-sectional plane of FIG. 1 extends vertically and includes the rotational axis R.

[0058] The brake assembly 10 comprises a braked member 14 that jointly rotates with the vehicle wheel about the rotational axis R. The connection between the braked member 14 and the vehicle wheel may be formed according to configurations of known disc brakes, e.g. by connecting both to a wheel hub and/or to a common axle component.

[0059] The brake assembly 10 also comprises a braking unit 16. The braking unit 16 has two brake pads 18 that are displaceable to contact the braked member 14, thereby slowing down or stopping its rotation. The braking unit 16 also has a hydraulic brake force generator 12.

[0060] The braked member 14 has two brake disc portions 20. In the shown example, these are provided and comprised by distinct brake disc members. The brake disc members are fixed to an axially extending connecting portion 22. Merely as an example, the connecting portion 22 is hollow and preferably has a tube-like hollow configuration to e.g. receive an axle component therein.

[0061] The brake disc portions 20 each extend orthogonally and concentrically to the rotational axis R. They have a round shape and may generally be configured similar to known brake disc, e.g. in terms of material and structure.

[0062] Each brake disc portion 20 has an axially outer contact surface 24 and an axially inner contact surface 26. The contact surfaces 24, 26 are each smooth and preferably metallic surfaces. The inner contact surfaces 26 of the brake disc portions 20 face inwards and face one another. The other contact surfaces 24 face outwards and away from the respective inner contact surface 26 of each brake disc portion 20.

[0063] In the example of FIG. 1, the outer contact surfaces 24 are not used for generating braking forces, i.e. are not contacted by any brake pad 18. An embodiment where the outer contact surfaces 24 are also used for generating great forces is described below with respect to FIG. 3.

[0064] The inner contact surfaces 26 confine a space 28 in between them. Said space 28 forms a circumferentially extending slot or ring within the braked member 14. Its axial side faces are formed by the inner contact surfaces 26. A bottom face 30 of the space 28 is provided by the connecting portion 22. In the shown example, a brake dust collector 32 is arranged at and/or forms at least a section of the bottom face 30. The brake dust collector 32 is a ring-shaped member or layer that is arranged at an outer circumferential surface of the connecting portion 22. It comprises an adhesive to which brake dust sticks instead of being emitted into the environment.

[0065] The braking unit 16 at least partially extends into the space 28. In particular, its brake pads 18 are preferably fully received within the space 28. The brake pads 18 extend substantially parallel to the inner contact surfaces 26 and/or the brake disc portions 20. The brake pads 18 each comprise a brake lining 19 formed by a friction material at a face thereof facing the respectively adjacent inner contact surface 26. More precisely, the brake lining 19 of the left brake pad 18 in FIG. 1 is directly adjacent and opposite to the left inner contact surface 26, whereas the brake lining 19 of the right brake pad in FIG. 1 is directly adjacent and opposite to the right inner contact surface 26.

[0066] The brake pads 18 are arranged at opposite sides of a housing 34 of the braking unit 16. The housing 34 may form or be formed by a brake caliper. Specifically, the brake pads 18 are arranged so that their brake linings 19 face away from one another and face a respectively adjacent inner contact surface 26. Also, the brake pads 18 are axially spaced apart from one another when viewed along the rotational axis R.

[0067] FIG. 1 shows a non-activated state of the brake assembly 10. Therefore, a small gap remains between the brake linings 19 and each contact surfaces 26 to prevent drag torque. When activated, the brake pads 18 move axially apart from one another as indicated by arrows in FIG. 1. An axial distance between the brake pads 18 is thus increased and each brake lining 19 is brought into contact with the respectively opposite inner contact surface 26. This generates frictional forces between the brake linings 19 and inner contact surfaces 26 which brake a rotation of the braked member 14.

[0068] In the shown example, the braking unit 16 and specifically its housing 34 comprises a hydraulic chamber 36. The hydraulic chamber 36 is part of or resembles the brake force generator 12.

[0069] According to a generally known configurations, a hydraulic pressure can be built up in said hydraulic chamber 36 for moving the brake pads 18, thus activating the brake. In more detail, each brake pad 18 is connected to a piston 38 that is slidingly received in the housing 34 and reaches into the hydraulic chamber 34. By increasing the pressure inside the hydraulic chamber 34, the pistons 38 are axially moved apart from one another and pushed outward. When releasing the pressure in the hydraulic chamber, the pistons 38 and thus the brake pads 18 can retract, so that the brake linings 19 are lifted off and away from the respectively opposite inner contact surfaces 26. This retraction movement may be supported by known elastic seals which act on the pistons 38.

[0070] It is to be noted that the pistons 38 as well as at least part of the hydraulic chamber 36 as well as part of the housing 34 are received within the space 28.

[0071] Further, any of these members as well as the brake pads 18 (and generally the braking unit 16 as a whole) may have a defined extension in the circumferential direction and/or orthogonally to the image plane so that a sufficiently large areal contact between the brake pads and the inner contact surfaces 26 is formed. Preferably, this circumferential extension is limited to below of 180° or below of 135° to increase compactness and save weight.

[0072] FIG. 2 shows a brake assembly 10 according to a second embodiment. The only difference to the first embodiment are stiffening structures 40 that are provided at the outer contact surfaces 24 of each brake disc portion 20. The stiffening structures 40 are formed as radially extending ribs. They may be distributed circumferentially, e.g. in a star-like manner, to support the brake disc portions 20 against bending.

[0073] Compared to FIG. 2, the connecting portion 22 is axially elongated to support the stiffening structures 40 at its outer circumferential surface. In one example, the stiffening structures 40 and connecting portion 22 from a one-piece member. Additionally or alternatively, the stiffening structures 40 may be an integral part of the brake disc portions 20.

[0074] FIG. 3 shows a brake assembly 10 according to a third embodiment. In this case, the outer contact surfaces 24 of the brake disc portions 20 are each contacted by a brake pad 18 as well to generate additional brake forces. Accordingly, the braking unit 16 also comprises two outer brake pads 18 each being adjacent to one of the outer contact surfaces 24. In the shown example, these brake pads 18 are configured similarly to the inner brake pads 18 that are arranged in the circumferential space 28 of the braked member 14.

[0075] The housing 34 of the brake unit 16 has axially outer portions 35 that face the outer contact surfaces 24. The axially outer portions 35 are axially positioned further outwards compared to the outer contact surfaces 24. Each axially outer portion 35 receives a piston 38 so that a brake pad 18 arranged at the respective axially outer portion 35 can be displaced in a similar manner as described above with respect to the first embodiment. For doing so, the hydraulic chamber 36 also extends into the axially outer portions 35. The inner brake pads 18 are generally configured and displaced similar to the first embodiment.

[0076] In order to generate brake forces, a hydraulic pressure within the hydraulic chamber 36 is built up, upon which all four brake pads 18 are displaced simultaneously towards their respectively opposite inner or outer contact surface 24, 26. Thus, one single brake force generator 12 comprising said hydraulic chamber 36 suffices to activate the braking function.

[0077] FIG. 4 depicts a brake assembly 10 according to a fourth embodiment. In this example, the brake pads 18 and inner contact surfaces 26 do not extend orthogonally to the rotational axis R, but are tilted at a different angle thereto (i.e., are inclined with respect to the rotational axis R). Preferably, however, the brake pads 18 still extend in parallel to their respectively opposite contact surface 26.

[0078] Each brake pad 18 moves along an individual movement axis M. The movement axes M preferably intersect a respective brake lining 19 and/or the opposite contact surface 26 orthogonally. The movement axes M extend at an angle relative to one another as well as to the rotational axis R. The movement axes M thus define a V-shape that, in the shown example, opens to the radial outside.

[0079] The contact surfaces 26 (and preferably the complete brake disc portions 20 at which they are provided) are equally tilted relative to the rotational axis R, i.e. do not extend orthogonally thereto. Preferably, the contact surfaces 26 are tilted (axially) inwardly and/or towards each other. This limits bending to the axial outside when the brake pads 18 are pushed against them.

[0080] Other than that, the brake assembly 10 and in particular the brake force generator 12 operates similar to the first and second embodiment. Even though this is not depicted, further brake pads 18 acting on the outer contact surfaces 24 as in the third embodiment could equally be provided in case of FIG. 4.