US-12618444-B2 - Rotation asymmetric brake drum for a drum brake of a motor vehicle

US12618444B2US 12618444 B2US12618444 B2US 12618444B2US-12618444-B2

Abstract

A brake drum for a drum brake of a motor vehicle, the brake drum having: a ring section extending concentrically about a rotation axis; and a circular wall section extending at an angle to the rotation axis; wherein in the brake drum has at least one portion that deviates from at least one of: a) a rotation symmetric configuration of the brake drum with respect to the rotation axis; b) a material comprised by at least one other portion of the brake drum.

Inventors

Hatem Shahin
Kai Braun
Lothar Wagner

Assignees

HL MANDO CORPORATION

Dates

Publication Date: 20260505
Application Date: 20230517
Priority Date: 20220518

Claims (8)

1 . A brake drum for a drum brake of a motor vehicle, the brake drum having: a ring section extending concentrically about a rotation axis; and a circular wall section extending at an angle to the rotation axis; wherein the brake drum has at least one portion such that the brake drum itself is rotation asymmetric with respect to the rotation axis, and wherein the at least one portion deviates from a rotation symmetric configuration of the brake drum with respect to the rotation axis; wherein the at least one portion comprises at least one recess extending axially inward from an axial end face of the ring section, and wherein the at least one recess is positioned rotation asymmetric with respect to the rotation axis.
2 . The brake drum according to claim 1 , wherein the at least one portion is comprised by one of the ring section and the wall section, wherein the respective other one of the ring section and wall section is rotation symmetric.
3 . The brake drum according claim 1 , wherein both of the ring section and the wall section each have a portion, said portions being different from one another in terms of at least one dimension and/or in terms of their circumferential position.
4 . The brake drum according to claim 1 , wherein, by way of the rotation asymmetry, a difference in eigenfrequencies is defined and/or is increased between the ring section and wall section.
5 . The brake drum according to claim 1 , wherein the deviation from the rotation symmetry is defined by the at least one recess.
6 . The brake drum according to claim 5 , wherein at least three recesses are provided that are non-uniformly distributed in a circumferential direction.
7 . Method for producing brake drum for a drum brake of a motor vehicle, the brake drum having: a ring section extending concentrically about a rotation axis; and a circular wall section extending at an angle to the rotation axis; wherein the method includes producing at least one portion of the brake drum such that the brake drum itself is rotation asymmetric with respect to the rotation axis, and wherein the at least one portion deviates from a rotation symmetric configuration of the brake drum with respect to the rotation axis, wherein the at least one portion comprises at least one recess extending axially inward from an axial end face of the ring section, and wherein the at least one recess is positioned rotation asymmetric with respect to the rotation axis.
8 . Method according to claim 7 , including: producing the at least one recess by an additive manufacturing technology.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims priority under 35 U.S.C. § 119 to German Patent Application No. 102022204951.9, filed on May 18, 2022 in the German Patent and Trade Mark Office, the disclosures of which are incorporated herein by reference. TECHNICAL FIELD The invention concerns a brake drum for a drum brake of a motor vehicle, such as a car, a truck or a bus. BACKGROUND Drum brakes are an established braking technology for motor vehicles. They typically comprise a brake drum having a contact surface at an inner circumferential face and a backing plate carrying brake shoes which have a friction lining for contacting the contact surface. An example can be found in KR 2006 006 3092 A. There remains room for improvement with respect to noise generation of existing drum brakes. For example, it has been determined that brake drums can significantly contribute to generating and/or to spreading vibrations which are perceivable as acoustic noise. SUMMARY It is therefore an object of this invention to improve the brake drum for a drum brake of a motor vehicle with respect to its vibration characteristics and in particular its potential for noise generation. This is object is achieved by a brake drum and a method according to the independent claims. Accordingly, a brake drum for a drum brake of a motor vehicle is disclosed, the brake drum having: a ring section extending concentrically about a rotation axis; anda circular wall section extending at an angle to the rotation axis; wherein in the brake drum has at least one (e.g. first) portion that deviates from at least one of: a) a (e.g. otherwise or predominantly) rotation symmetric configuration of the brake drum with respect to the rotation axis;b) a material comprised by at least one other (e.g. second) portion of the brake drum, said other portion e.g. being the ring section or the wall section. Terms such as axial, radial and circumferential used herein may relate to the rotation axis. An axial direction may extend along said axis, a radial direction may extend orthogonally thereto and a circumferential direction may extend about said axis. With option a) and b) above, the disclosed brake drum has further design parameters compared to existing designs which may help to limit vibrations and thus the level of generated noise. According to option a), the brake drum is rotation symmetric apart from the at least one portion. Put differently, the brake drum would be completely rotation symmetric if the at least one portion was not provided (and the brake drum was instead configured at said portion similarly to its adjacent portions). Accordingly, the at least one portion may render the brake drum rotation asymmetric and/or define a rotation asymmetric portion thereof. The rotation asymmetry may in particular include that there is only one rotational angle (in particular a rotation angle of 360°, i.e. a full turn) at which the brake drum may resemble its pre-rotation shape and/or configuration. Accordingly, the rotation asymmetry may exclude designs having a number of distinct partial turns each marked by rotational angles of less than 360° and each resulting in the brake drum resembling its pre-rotation shape and/or configuration. Such partial turns could e.g. be defined by distributing local shape deviations at regular angular distances from one another along the brake drum's circumference. By providing the rotation asymmetry, the eigenfrequencies of the brake drum can be more clearly set apart from eigenfrequencies of components mechanically coupled thereto, e.g. from axle components or other brake components. Further and e.g. depending on a position of the at least one portion, this may allow for the eigenfrequencies of different sections of the brake drum (in particular of the ring section and wall section) to be clearly separated. Separating the eigenfrequencies limits the propagation of vibrations and thus the level of generated noise. Put differently, this way the extent to which the brake drum acts as a source of vibration can be limited. According to option b), the brake drum may comprise at least one portion having a first material and at least one other portion having a deviating second material. Said other portion may comprise the remainder of the brake drum or a majority thereof, e.g. in terms of volume or weight. This too helps to separate eigenfrequencies between different sections of the brake drum. Also, this may help to limit the brake drum acting as a responsive member with respect to vibrations, thus limiting the level of noise emitted by the brake drum into the surroundings. The latter concerns in particular embodiments in which the deviating material is arranged at or near a surface of the brake drum. The brake drum may be an integral member or, differently put, a one-piece member. Especially in case of option b), it may be a multi-piece member, wherein the at least one portio