Drum brake system with two tension springs

Patent metadata

Field	Value
Publication number	US-12523265-B2
Application number	US-202217984515-A
Country	US
Kind code	B2
Filing date	Nov 10, 2022
Priority date	Nov 10, 2021
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

Abstract

The present invention relates drum brake system, comprising a back plate assembly and a brake drum ( 1 ) that is rotatable with respect to the back plate assembly, the back plate assembly comprising: a back plate ( 2 ); two brake shoes ( 3, 3 ′), the two brake shoes ( 3, 3 ′) being pivotably connected to the back plate ( 2 ), pivot axes ( 4, 4 ′) of the brake shoes ( 3, 3 ′) being disposed at or near first ends of the brake shoes ( 3, 3 ′); an actuator housing ( 5 ) with two pistons ( 6, 6 ′), the two pistons ( 6, 6 ′) being configured to move outwardly, to press each piston ( 6, 6 ′) against one of the brake shoes ( 3, 3 ′) to pivot the respective brake shoe ( 3, 3 ′) outwardly about its pivot axis ( 4, 4 ′), and to press the respective brake shoe ( 3, 3 ′) against the brake drum ( 1 ) for braking; a return spring ( 7 ) extending between the brake shoes ( 3, 3 ′) and being connected to both brake shoes ( 3, 3 ′), the return spring ( 7 ) being configured ( 7 ) to exert a retracting spring force that pulls both brake shoes ( 3, 3 ′) away from the brake drum; two tension springs ( 8, 8 ′) and a holder arrangement ( 9 ), inner ends of each of the two tension springs ( 8, 8 ′) being connected to the holder arrangement ( 9 ), an outer end of the first tension spring ( 8 ) of the two tension springs ( 8, 8 ′) being connected to a first brake shoe ( 3 ) of the two brake shoes ( 3, 3 ′) and an outer end of the second tension spring ( 8 ′) of the two tension springs ( 8, 8 ′) being connected to a second brake shoe ( 3 ′) of the two brake shoes ( 3, 3 ′).

First claim

The invention claimed is:

1 . A drum brake system, comprising a back plate assembly and a brake drum ( 1 ) that is rotatable with respect to the back plate assembly,
the back plate assembly comprising: a back plate ( 2 ); two brake shoes ( 3 , 3 ′), the two brake shoes ( 3 , 3 ′) being pivotably connected to the back plate ( 2 ), pivot axes ( 4 , 4 ′) of the brake shoes ( 3 , 3 ′) being disposed at positions adjacent to first ends of the brake shoes ( 3 , 3 ′); an actuator housing ( 5 ) with two pistons ( 6 , 6 ′), the two pistons ( 6 , 6 ′) being configured to move outwardly, to press each piston ( 6 , 6 ′) against one of the brake shoes ( 3 , 3 ′) to pivot the respective brake shoe ( 3 , 3 ′) outwardly about its respective pivot axis ( 4 , 4 ′), and to press the respective brake shoe ( 3 , 3 ′) against the brake drum ( 1 ) for braking; a return spring ( 7 ) extending between the brake shoes ( 3 , 3 ′) and being connected to both brake shoes ( 3 , 3 ′), the return spring ( 7 ) being configured to exert a retracting spring force that pulls both brake shoes ( 3 , 3 ′) away from the brake drum ( 1 ); a pair of tension springs ( 8 , 8 ′) comprising a first tension spring ( 8 ) and a second tension spring ( 8 ′), and a holder arrangement ( 9 ), inner ends of the first tension springs and the second tension spring ( 8 ′) being connected to the holder arrangement ( 9 ), an outer end of the first tension spring ( 8 ) being connected to a first brake shoe ( 3 ), and an outer end of the second tension spring ( 8 ′) being connected to a second brake shoe ( 3 ′), wherein the holder arrangement ( 9 ) is connected to the actuator housing ( 5 ) and, wherein the holder arrangement ( 9 ) comprises a movable holder for the first tension spring ( 8 ) and for the second tension spring ( 8 ′) for adjusting pre-tension conditions of the first tension spring ( 8 ) and the second tension spring ( 8 ′).

2 . The drum brake system according to claim 1 , wherein the return spring ( 7 ) extends between second ends of the brake shoes ( 3 , 3 ′) and is connected to both brake shoes ( 3 , 3 ′) at positions adjacent to the second ends of the brake shoes ( 3 , 3 ′), and wherein the outer ends of the tension springs ( 8 , 8 ′) are connected to the brake shoes ( 3 , 3 ′) between the return spring ( 7 ) and the respective pivot axis ( 4 , 4 ′) of each brake shoe ( 3 , 3 ′).

3 . The drum brake system according to claim 1 , wherein at least one of the tension springs ( 8 , 8 ′) is arranged at a non-vanishing angle (α, β) with respect to the return spring ( 7 ).

4 . The drum brake system according to claim 3 , wherein the non-vanishing angle (α, β) with respect to the return spring ( 7 ) is provided by having the inner end of the at least one of the tension springs ( 8 , 8 ′) closer to the return spring ( 7 ) than the outer end of the at least one of the tension springs ( 8 , 8 ′).

5 . The drum brake system according to claim 1 , wherein for each of the tension springs ( 8 , 8 ′), angles (α, β) between the tension springs ( 8 , 8 ′) and the return spring ( 7 ) is between 3 degrees and 30 degrees.

6 . The drum brake system according to claim 5 , wherein a first angle (α) between the first tension spring ( 8 ) and the return spring ( 7 ) differs from a second angle (β) between the second tension spring ( 8 ′) and the return spring ( 7 ), wherein a difference between the first angle (α) and the second angle (β) is between 2 degrees and 5 degrees.

7 . The drum brake system according to claim 1 , wherein the tension springs ( 8 , 8 ′) are arranged in a non-symmetric manner with respect to each other, in particular attachment of the inner ends of the tension springs ( 8 , 8 ′) at the holder arrangement ( 9 ) being provided at different heights and/or attachment of the outer ends of the tension springs ( 8 , 8 ′) at the brake shoes ( 3 , 3 ′) being provided at different heights.

8 . The drum brake system according to claim 1 , wherein the tension springs ( 8 , 8 ′) comprise or consist of steel and/or aluminium and/or plastic.

9 . The drum brake system according to claim 1 , wherein at least one of the tension springs ( 8 , 8 ′) has a spring property that varies over its length.

10 . The drum brake system according to claim 9 , wherein the at least one of the tension springs ( 8 , 8 ′) has, over its length, a varying winding diameter and/or a varying wire diameter and/or a varying winding height.

11 . The drum brake system according to claim 1 , wherein a spring characteristic of the first tension spring ( 8 ) is different from a spring characteristic of the second tension spring ( 8 ′).

12 . The drum brake system according to claim 11 , wherein at least one of the tension springs ( 8 , 8 ′) has a linear characteristic.

13 . The drum brake system according to claim 1 , further comprising a control circuit for adjusting pre-tensioning of the tension springs ( 8 , 8 ′) based on driving conditions and/or wear.

Assignees

• Hl Mando Corp

Inventors

• Shahin Hatem
• Wagner Lothar
• Braun Kai

Classifications

• F16D65/22 Primary

  adapted for pressing members apart {, e.g. for drum brakes} · CPC title

• F16D2127/02

  Release mechanisms · CPC title

• F16D2121/04

  acting on a piston-type actuator, e.g. for liquid pressure · CPC title

• F16D51/22 Primary

  mechanically actuated · CPC title

• F16D65/09 Primary

  Pivots or supporting members therefor · CPC title