Radial Drum Brake Return Spring Layout for Residual Torque Release
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Solution Overview
Problem
Existing drum brakes in commercial vehicles experience undesirable residual grinding torque due to incomplete release of brake linings from the brake drum, leading to inefficiencies and increased fuel consumption.
Innovation Solution
Incorporation of return springs in the drum brake design, which are pre-tensioned to ensure brake linings return to a non-braking position, preventing residual torque by providing a defined response pressure and using various spring types like flat, wave, and coil springs to facilitate this movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If elastic deformations are used to return the service brake piston to its original position, then the brake can be released without additional components, but the brake linings may not return completely to the non-braking position, leaving residual friction torque
Solution Approach 1:
A return spring is introduced as an intermediary component between the brake lining and the anchor housing. This spring actively pushes the brake lining away from the brake drum inner surface after braking, ensuring complete separation and eliminating residual friction torque that elastic deformations alone cannot prevent.
Solution Approach 2:
The return spring is designed to automatically return the brake lining to its retracted position without requiring external intervention or additional active components. The spring stores energy during braking and releases it automatically to push the brake lining away, making the release process self-service and reliable.
2Object-generated harmful factors
If return springs are added to ensure complete brake lining retraction, then residual grinding torque is eliminated, but the device complexity increases
Solution Approach 1:
The return spring serves as a simple intermediary component that mediates between the brake lining and the anchor housing. By placing this single spring in the available space, the system achieves complete brake lining retraction and eliminates residual grinding torque without requiring complex mechanisms or multiple components.
Solution Approach 2:
The return spring is pre-tensioned during installation to provide the necessary force for complete brake lining retraction. By carefully selecting the spring parameters (pre-tension, stiffness, length), the system achieves reliable brake release without over-complicating the design, balancing performance improvement with design simplicity.
3Force
If pre-tensioned return springs are used to define response pressure, then a predetermined contact pressure is achieved for brake activation, but the manufacturing precision requirements increase
Solution Approach 1:
The return spring is designed with specific parameters (pre-tension, stiffness, free length) that define the response pressure for brake activation. By carefully selecting and pre-tensioning the spring during installation, the system achieves a predetermined contact pressure between the brake lining and drum, ensuring consistent braking performance while managing manufacturing precision requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces residual grinding torque, enhancing efficiency and extending the service life of brake components while improving fuel economy.
Implementation Method 1
it is moved back towards its original position due to elastic deformations in the system
Implementation Method 2
Since the return springs are always installed with preload, a predetermined contact pressure is necessary to move the brake linings of the drum brake in the closing direction
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A radially actuated drum brake (1) for a commercial vehicle comprises a brake drum (2) rotatably mounted about an axis of rotation (AR), an anchor housing (5) with bearing receptacles (51) for brake linings (3), at least two brake linings (3) mounted in a receiving space of the brake drum (2) in respective bearing receptacles (52) of the anchor housing (5), each of the brake linings (3) having a friction lining carrier (32), a friction lining (31) arranged thereon and a pressure piece (7) arranged on an underside of the lining carrier (32) facing away from the friction lining, which projects radially in the direction of the axis of rotation (AR) of the brake drum (2) through an opening (54) of the respective bearing receptacle (52) of the anchor housing (5), a clamping device (4) arranged on a cylindrical sleeve (51) of the anchor housing (5) with at least one pressure element,with which the brake linings (3) can be pressed against an inner surface of the brake drum (2) in a clamping direction (r) radially to the axis of rotation (AR) of the brake drum (2), wherein at least one return spring is provided in the receiving space of the brake drum (2) on each of the brake linings (3), the return spring bearing against a lower surface (53) of the bearing receptacle (52) of the armature housing (5) facing away from the brake lining (3), with which the respective brake lining (3) can be moved from a braking position in contact with the inner surface (21) of the brake drum (2) to a non-braking position away from the inner surface (21) of the brake drum (2).