Radial Drum Brake Lining Retraction With Preloaded Restoring Springs
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Solution Overview
Problem
Existing drum brakes in commercial vehicles experience undesirable residual grinding torque due to incomplete retraction of brake linings, leading to inefficiencies and potential wear on friction partners.
Innovation Solution
Incorporation of restoring springs that are preloaded to ensure complete retraction of brake linings, utilizing various spring types such as flat, corrugated, or helical springs to maintain a predefined contact pressure and prevent residual torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the service brake piston is vented to release the brakes, then the piston is displaced back to the original position, but the brake linings are not completely moved back into the non-braking position due to reduced elastic deformation
Solution Approach 1:
The restoring spring is preloaded in the non-braking position to exert a preliminary restoring force on the brake lining. This preloading ensures that when the service brake piston is vented, the brake lining is actively pushed back to the non-braking position without relying solely on elastic deformation, thereby preventing residual grinding torque.
Solution Approach 2:
The restoring spring provides a self-service mechanism by automatically exerting a restoring force on the brake lining during the brake release process. This eliminates the need for additional actuation mechanisms and ensures reliable retraction of the brake lining to the non-braking position.
2Reliability
If restoring springs are installed with preloading to define response pressure, then a predefined contact pressure is necessary to activate the drum brake, but the device complexity increases
Solution Approach 1:
The restoring spring is designed with specific preloading parameters to define the response pressure required for brake activation. By adjusting the preloading force and spring characteristics, the system achieves reliable brake activation control at predefined contact pressure points, transforming a quality parameter (response pressure) into a controllable design parameter.
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
Prevents residual grinding torque, reduces fuel consumption, and extends the service life of brake components by ensuring consistent retraction of brake linings.
Implementation Method 1
If the elastic deformation is reduced, it can happen that the service piston and thus also the pressing wedge and the brake lining are not or not completely moved back into the non-braking position
Implementation Method 2
Since the restoring springs are always installed with preloading, a predefined contact pressure is necessary to move the brake linings of the drum brake in the application direction
Data Source
AI summary
A radially actuated drum brake for a commercial vehicle has a brake drum, an anchor housing with bearing receptacles for brake linings, at least two brake linings, which are mounted in respective bearing receptacles in an accommodation space of the brake drum, each of the brake linings having a friction lining carrier, a friction lining arranged thereon, and a pressure piece, which is arranged on an underside of the lining carrier, the underside facing away from the friction lining, and protrudes radially in the direction of the rotational axis of the brake drum through an opening in the relevant bearing receptacle. An application device is arranged on a cylinder sleeve of the anchor housing and has at least one pressing part with which the brake linings can be pressed against an inner lateral face of the brake drum in an application direction radial to the rotational axis of the brake drum. In the accommodation space, there is provided on each of the brake linings at least one restoring spring, which is supported such that it bears against an underside of the bearing receptacle of the anchor housing, and with which the relevant brake lining can be moved from a braking position, bearing against the inner lateral face of the brake drum, into a non-braking position away from the inner lateral face of the brake drum.