Sliding Caliper Brake Return Spring Wear Compensation

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Solution Overview

Problem

In motor vehicle disc brakes with sliding calipers, the existing elastic return springs often fail to adequately separate the brake pads from the disc after braking, leading to premature wear and overheating due to residual friction, which causes torque and reduces vehicle performance.

Innovation Solution

A new design for the outer brake pad's elastic return spring, featuring a plastically deformable section that compensates for wear clearance by forming an accordion fold, is integrated with the fixed support, ensuring proper separation and maintaining a constant operating clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastic return springs are used to push brake pads back to inactive position, then brake pads are returned to inactive position, but the springs may not provide sufficient force to ensure adequate separation distance

Engineering Contradiction:
Improvebrake pad return functionVSAvoidseparation force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent changes the mechanical parameters of the return spring system by using two paired springs instead of one, and designs them with specific load and stiffness characteristics. The springs are configured to provide sufficient cumulative force to ensure adequate separation distance while maintaining reliable return function.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If brake pads are not adequately separated from the disc, then the structure is simpler, but premature wear and overheating occur due to permanent friction

Engineering Contradiction:
Improvereturn spring configurationVSAvoidfriction lining service life
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent optimizes the mechanical parameters of the return springs (load, stiffness) to provide sufficient separation force, ensuring the brake pads are pushed back to a position with adequate clearance from the disc. This prevents permanent friction contact during non-braking operation, eliminating premature wear and overheating issues.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If different mechanical characteristics are used for inner and outer brake pad springs, then proper function is achieved, but device complexity increases

Engineering Contradiction:
Improvebrake pad functionVSAvoidspring specification variety
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by designing the inner and outer return springs with different mechanical characteristics suited to their specific functional requirements. The inner spring (cooperating with piston front face) and outer spring are optimized independently for their respective positions and load conditions, improving overall system reliability.

Inventive Principle:
Principle #3Local quality

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

This design effectively prevents residual torque and maintains consistent brake performance by ensuring the brake pads return to their inactive position, reducing wear and overheating, and allowing for balanced caliper operation.

Implementation Method 1

the spring comprising at least one plastically deformable section, under the effect of an axial tensile force, forming said means for compensating for the wear clearance, this plastically deformable section being shaped to be plastically elongated when the travel of the braking shoe up to its active position is greater than the determined operating clearance

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

an elastic return spring comprises at least one section of axial orientation which is elastically deformable by traction between a state of rest and a state of maximum elongation, the value of which is equal to the determined operating play

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

each of the annular tracks of the latter nevertheless rubs permanently against the friction lining carried by the associated brake pad. The friction linings thus undergo premature non-functional wear

Methodology Applied
Scientific EffectFriction wear: Friction

Data Source

PatentEP3020996B1Sliding caliper disk brake including a central return spring of an exterior brake shoe including wear play compensation means, spring and replacement kit
Publication Date: 2020.04.22 CHASSIS BRAKES INT BV
  • EP3020996B1 patent drawingFigure 1
  • EP3020996B1 patent drawingFigure 2~3
  • EP3020996B1 patent drawingFigure 4~5

AI summary

The invention relates to a sliding caliper disc brake (10) comprising an outer brake pad (18E) mounted to slide within the fixed brake support, characterized in that the disc brake comprises an outer central spring (48E) for elastically returning the outer brake pad (18E) to its inactive position, which is fixed to an associated central portion (63) of the outer brake pad (18E) and whose front portion (50) is axially fixed to an associated central portion (58) of the fixed support (14). For its return to its inactive position, the inner brake pad is axially fixed to the brake piston.