DRUM BRAKE ASSEMBLY WITH BRAKE LINER INTEGRATED INTO BRAKE DRUM

Abstract

The disclosure concerns a Drum brake assembly (10) for a motor vehicle,

the drum brake assembly (10) having: a brake drum housing (16); at least one brake shoe (26); a brake lining (18);
wherein the brake lining (18) is arranged at an inner circumferential face (24) of the brake drum housing (16) and the brake shoe (26) is displaceable relative to the brake lining (18), so as to contact the brake lining (18) during braking. Also disclosed is a drake drum assembly (14) for a motor vehicle Method a for producing such a brake drum assembly (14).

Claims

1. A drum brake assembly (10) for a motor vehicle, the drum brake assembly (10) having: a brake drum housing (16); at least one brake shoe (26); a brake lining (18); wherein the brake lining (18) is arranged at an inner circumferential face (24) of the brake drum housing (16) and the brake shoe (26) is displaceable relative to the brake lining (18), so as to contact the brake lining (18) during braking.

2. The drum brake assembly (10) according to claim 1, wherein the brake lining (18) comprises a friction material.

3. The drum brake assembly (10) according to claim 1; wherein at least a contact surface (28) of the brake shoe (26) that is configured to contact the brake lining (28) during braking is made from a material that is different from the material of the brake lining (28).

4. The drum brake assembly (10) according to claim 3, wherein at least the contact surface (28) of the brake shoe (26) comprises a material that is harder than a material of the brake lining (28).

5. The drum brake assembly (10) according to claim 1, wherein the brake shoe (26) comprises a metallic material and in particular cast iron.

6. The drum brake assembly (10) according to claim 1, wherein the brake drum housing (16) comprises a material that is different from a material of the brake lining (18) and that is in particular lighter than a material of the brake lining (18).

7. The drum brake assembly (10) according to claim 1, wherein the material of the brake shoe (26) has a larger coefficient of thermal expansion than a material of the brake lining (18) and/or of the brake drum housing (16).

8. The drum brake assembly (10) according to claim 1, wherein the brake lining (18) forms a preferably continuous ring extending along the inner circumferential face (24) of the brake drum housing (18).

9. The drum brake assembly (10) according to claim 1, wherein the brake lining (18) comprises a number of brake lining segments that are arranged in a ring-like manner along the inner circumferential surface (24).

10. Brake drum assembly (14) for a motor vehicle, the brake drum assembly (14) having a brake drum housing (16) and a brake lining (18), wherein the brake lining (18) is arranged at an inner circumferential face (24) of the brake drum housing (18).

11. Method a for producing a brake drum assembly (14) for a motor vehicle, the method comprising arranging a brake lining (18) at an inner circumferential surface (24) of a brake drum housing (16), in particular so that the brake lining (18) forms a ring extending along an inner circumferential face (24) of the brake drum housing (16).

Description

[0043] Embodiments of the invention are described in further detail below with respect to the attached schematic figures. Same features may be marked with the same reference signs throughout the figures.

[0044] FIG. 1 is sectional view of a drum brake assembly according to a first embodiment, the sectional plane including a rotational axis of the brake drum housing.

[0045] FIG. 2 is a front view of the drum brake assembly of the first embodiment.

[0046] FIG. 3 is front view of a drum brake assembly according to a second embodiment.

[0047] FIG. 1 shows a drum brake assembly 10 according to a first embodiment of the invention. The drum brake assembly 10 is depicted in a sectional view with the sectional plane including a rotational axis R.

[0048] The drum brake assembly 10 is mounted to an axle stub 12 which also carries a wheel hub 13. The drum brake assembly 10 comprises a brake drum assembly 14 having a brake drum housing 16 and a brake lining 18. Both of the brake drum housing 16 and brake lining 18 are rotationally symmetric with respect to the rotational axis R.

[0049] The brake drum housing 16 is a one-sided opened cylindrical member having a (in FIG. 1) left base portion 20 that extends at an angle and preferably orthogonally to the rotational axis R. Further, it comprises a cylinder mantle portion 22 that preferably extends in parallel to the rotational axis R. On the other hand, it lacks a right base portion opposite to the left base portion 20. This shape of the brake drum housing 16 may correspond to known shapes, but the brake drum housing 16 is not limited thereto it may e.g. be configured according to other known shapes known in the prior art.

[0050] The brake drum housing 16 is fixed to the axle stub 12 and/or wheel hub 13 so as to jointly rotate therewith. A non-depicted wheel is also connected to the wheel hub 13 for a joint rotation therewith and thus jointly rotates with the brake drum housing 16. According to known configurations, the wheel hub 13 may comprise non-depicted bolts that axially extend towards the right side of FIG. 1 and through the base portion 20 of the brake drum housing 16 for mounting the wheel thereto.

[0051] The brake lining 18 is configured as a continuous ring-shaped material layer of limited thickness (the thickness being measured in a radial direction). It is arranged at and preferably releasably fixed to an inner circumferential face 24 of the brake drum housing 16. In the shown example, the inner circumferential face 24 is comprised by the cylinder mantle portion 22. Therefore, the brake lining 18 forms an innermost surface of the drum brake assembly 14 that is contactable from a radial inside of the brake drum housing 16 and specifically from a radial inside of the cylinder mantle portion 22.

[0052] The brake lining 18 is made from a friction material according to known configurations and specifically from a friction material according to any of the examples disclosed herein.

[0053] The drum brake assembly 10 further comprises two brake shoes 26, this number being a mere example. The brake shoes 26 are made from a metallic material and preferably from cast iron. They do not comprise a brake lining material and are generally made from a different material compared to the brake lining 18. On their radial outside facing the brake lining 18, the brake shoes 26 each comprise a contact surface 28 that are correspondingly curved to the brake lining 18 (see also FIGS. 2 and 3 below).

[0054] The brake shoes 26 are radially displaceable towards and away from the brake lining 18, e.g. by making use of any of the existing technologies in the prior art. For example, non-depicted hydraulic cylinders may be used to provide said displacement. The displacement indicated by arrows in FIG. 1.

[0055] As a result of said displacement, each contact surface 28 can be brought into contact with a respectively opposite brake lining 18 to generate frictional forces, thereby reducing the speed of rotation of the non-depicted wheel.

[0056] At frequent brake activations, high thermal loads may occur as a result of the generated frictional forces. The metallic brake shoes 26 may in reaction thereto thermally expand. This thermal expansion takes place towards the brake lining 18, thereby reducing a radial distance thereto. In particular, the thermal radial expansion towards the brake lining 18 may be larger than a possibly occurring thermal radial expansion of a brake drum assembly 14 that radially moves the brake lining 18 outward and thus (theoretically) away from the brake shoes 26.

[0057] From the driver's perspective, this means that contrary to existing solutions, the brake pedal feel continues to show a satisfactory responsiveness even at high thermal loads due to a limited or even no increase in the brake pedal travel. That is, a problem known from the prior art according to which a radial distance of the (in the prior art) radially inner brake lining from a (in the prior art radially outer) contact surface increases at high thermal loads is prevented.

[0058] FIG. 2 is a front view of the embodiment of FIG. 1 with the rotational axis R extending orthogonally to the image plane. From this figure, the ring-shaped configuration of the brake lining 18 at a radial outside of and/or circumferentially surrounding the brake shoes 26 is particularly clear. Also, the curved shape of the contact surfaces 28 of the brake shoes 26 is shown. Again, arrows indicate the possibility of a linear displacement of the brake shoes 26 towards the brake lining 18 to produce a braking effect.

[0059] FIG. 3 is a front view similar to FIG. 2 but depicting a further embodiment with an increased number of brake shoes 26. Specifically, four brake shoes 26 are shown that are equally spaced apart from one another at angles of 90°.