Disc Brake Pad Guide Spring Noise Reduction

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Solution Overview

Problem

Existing disc brake spring devices often produce high-pitched noise during light braking or reversing due to lateral force-induced noise from the elasticity of the spring, which is not adequately dampened.

Innovation Solution

A guide spring system with a lower blade and two leaf springs, where the radial force exerted by one spring on the yoke housing is equal to the radial force on the brake pad lug, decoupling lateral forces and minimizing noise by ensuring the blade remains stable and pressed against the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a single spring is used to guide the brake pad lug in the housing, then the spring can dampen impact during braking, but the elasticity of the spring induces high-pitched noise during light braking or reversing

Engineering Contradiction:
Improveimpact noise during brakingVSAvoidhigh-pitched noise during light braking
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The single spring is segmented into two separate springs: a first spring for dampening impact during heavy braking, and a second spring for preventing high-pitched noise during light braking. Each spring is optimized for its specific function, with the first spring having higher stiffness for impact damping and the second spring having lower stiffness for noise prevention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the guide spring system are assigned different stiffness properties. The first spring (lower blade region) has higher stiffness for impact damping, while the second spring (upper blade region) has lower stiffness for noise prevention. This local differentiation allows each part to perform its specific function optimally.

Inventive Principle:
Principle #3Local quality

2Strength

If the spring stiffness is increased to dampen impact during braking, then impact noise is reduced, but lateral force-induced noise increases during light braking

Engineering Contradiction:
Improveimpact damping capabilityVSAvoidlateral force-induced noise
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The spring system is divided into two segments with different stiffness values. The first spring has higher stiffness for impact damping, while the second spring has lower stiffness to minimize lateral forces during light braking operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stiffness parameter is varied across different parts of the spring system. The first spring uses a higher stiffness parameter for impact damping, while the second spring uses a lower stiffness parameter to reduce lateral force-induced noise during light braking.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the spring elasticity is increased to improve guidance, then lateral movement is better controlled, but noise during light braking increases

Engineering Contradiction:
Improveguidance qualityVSAvoidnoise during light braking
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The guidance function is differentiated by location: the first spring provides rigid guidance for heavy braking, while the second spring provides softer guidance for light braking operations, reducing noise while maintaining control.

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

The solution effectively reduces noise by maintaining a stable contact surface and minimizing lateral force-induced noise, providing improved damping and reduced high-pitched sounds during light braking and reversing.

Implementation Method 1

a first spring located between the lower blade and the lower face of the housing and tending to separate the lower blade from the lower face of the housing

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a second spring located between the lower blade and the underside of the shoe lug and tending to separate the underside of the shoe from the lower blade

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

To dampen the impact of the lugs in their housing and thus attenuate the noise, provision is made, in known manner, for a spring located between each lug and its housing. This damping effect is obtained by deformation of the spring.

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2088346B1Guide for a disc brake pad support
Publication Date: 2011.10.12 ROBERT BOSCH GMBH
  • EP2088346B1 patent drawingFigure 1
  • EP2088346B1 patent drawingFigure 2~3
  • EP2088346B1 patent drawingFigure 4~6c

AI summary

The spring (4) has a lower plate (43) arranged between a lower surface (56) of a housing (54) and a lower surface (12) of a lug (13) of a brake pad. A spring (42) e.g. steel tab, is situated between the lower plate and the lower surface of the housing for spacing the lower plate from the lower surface of the housing. A spring (44) e.g. steel tab, is situated between the lower plate and the lower surface of the lug of the brake pad for spacing the lower surface of the lug of the brake pad from the lower plate.