Brake Pad Retaining Spring Design for Reduced Heat Load

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Solution Overview

Problem

The existing brake pad holders for disc brakes face issues with spring characteristic changes due to limited connection points, thermal loads, and leaf spring geometry, leading to reduced service life and functional reliability.

Innovation Solution

A brake pad holder design featuring a pad retaining spring with angled legs and a bulge, supported by recesses and humps on the pad carrier plate, which allows for controlled deflection and reduced heat load, along with a pad retaining clip that ensures compatibility with specific brake pads through coding features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the pad retaining spring is fastened to retaining tabs with limited connection points, then the attachment structure is simple, but the spring characteristics change due to strong deflection and the service life is reduced

Engineering Contradiction:
Improveattachment structureVSAvoidspring characteristic stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The pad retaining spring is divided into multiple connection points along its length, distributing the attachment locations rather than using only two distant tabs. This segmentation reduces the deflection moment at each connection point and prevents strong spring deflection that would alter spring characteristics, thereby maintaining reliability while keeping the attachment structure relatively simple.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring design incorporates dynamic considerations by optimizing the distribution of connection points to accommodate the dynamic loads and deflections experienced during brake operation. This ensures the spring maintains its characteristic behavior under varying operational conditions.

Inventive Principle:
Principle #15Dynamics

2Power

If the pad retaining spring is subjected to frictional heat during braking, then the braking function is achieved, but the thermal load changes the spring characteristics and reduces service life

Engineering Contradiction:
Improvebraking functionVSAvoidheat load on spring
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The critical connection points of the spring are positioned to be extracted or separated from the high-temperature friction zone. By strategically locating the attachment points away from the primary heat generation area, the spring material experiences reduced thermal exposure, minimizing thermal-induced characteristic changes and extending service life while maintaining effective braking power.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spring design incorporates thermal management considerations by using the brake caliper structure and surrounding components as thermal intermediaries or heat sinks. The spring is positioned to utilize these surrounding structures for heat dissipation, reducing the direct thermal load on the spring material during braking operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the pad retaining spring has a leaf shape resting on the pad retaining bracket, then the spring can be simply manufactured, but the frictional resistance is high when brake pads are displaced

Engineering Contradiction:
Improvespring manufacturingVSAvoidfrictional resistance
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The spring design incorporates curved or rounded contact surfaces instead of flat leaf-shaped surfaces that rest on the bracket. This curvature reduces the contact area and frictional resistance during brake pad displacement, while the spring can still be manufactured using standard forming processes, maintaining ease of manufacture with improved performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The spring geometry is optimized by changing parameters such as contact surface area, curvature radius, and material properties to reduce frictional resistance. These parameter adjustments allow the spring to maintain its manufacturability while significantly reducing the harmful frictional effects during operation.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If multiple connection points are provided for the pad retaining spring, then the spring characteristic stability is improved, but the production cost increases

Engineering Contradiction:
Improvespring characteristic stabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The spring is segmented into multiple connection points that can be integrated into the spring forming process itself, rather than requiring separate attachment operations. This segmentation approach maintains spring characteristic stability while avoiding additional manufacturing steps that would increase production cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The multiple connection points are merged into the spring's overall geometry and forming process, combining the spring creation and attachment point formation into a single manufacturing operation. This integration maintains reliability through multiple connection points while preventing production cost increases by eliminating separate manufacturing steps.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the service life and functional reliability of brake pad holders by minimizing spring fractures and ensuring only suitable brake pads are used, resulting in improved operational safety and cost-effective production.

Implementation Method 1

the pad retaining spring, which is designed as a leaf spring and is attached to the brake pad in the upper edge region facing a mounting opening of the brake caliper in such a way that they are prestressed by a pad retaining bracket

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

An influencing of the spring characteristics to an unforeseeable extent also results from a geometry-related thermal load on the pad retaining spring due to frictional heat generated during braking

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

the pad retaining springs rest with their broad side on the pad retaining bracket, which leads to a correspondingly high frictional resistance when the brake pads are displaced by braking

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2050980B1Brake cover holder on a disk brake and brake cover
Publication Date: 2017.05.24 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP2050980B1 patent drawingFigure 1
  • EP2050980B1 patent drawingFigure 2
  • EP2050980B1 patent drawingFigure 3

AI summary

The retainer supports two spring-loaded brake linings (2) in a lining groove (5) of a fixed brake carrier or brake caliper. A lining carrier plate (3) of each lining carries a friction lining (4). Each brake lining has a lining retaining spring (6) formed from a spring wire and formed as a flat spring. The spring has a camber (8) formed in a middle region transverse to a resilient moving direction. A lining retaining bracket (7) lies at the camber, and a bump corresponding to the camber is provided on an edge side of the lining carrier plate.