Self-Adjusting Brake Pad Return Spring With Assembly Preload

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Solution Overview

Problem

Existing brake pad return springs are not active from their first use, requiring several applications to activate their return function, which can lead to residual braking issues due to plastic deformation over wear.

Innovation Solution

A brake pad return spring design with a V-shaped portion connecting fixing portions, where the branch on the disc brake attachment side is initially straight and deforms to form a fold during assembly, ensuring immediate activation by preload, allowing the spring to perform its return function from the first braking application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the return spring is designed with a V-shaped joint and folds formed during manufacturing, then the spring structure is simple and easy to manufacture, but the spring is not active from the first use and requires several applications to activate

Engineering Contradiction:
Improvespring manufacturing simplicityVSAvoidimmediate activation reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The spring is pre-assembled on the brake pad plate before installation, and the second branch is pre-positioned in a substantially flat configuration. During assembly, when the second fixing portion is attached to the fixed point, the second branch automatically deforms plastically to form the fold and activate the spring preload, ensuring immediate functionality from first use

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the spring deforms plastically during operation to compensate for wear, then the spring adapts to pad wear and maintains constant distance, but the spring is not active during initial applications

Engineering Contradiction:
Improvewear compensation capabilityVSAvoidinitial activation reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The spring is pre-loaded during the assembly process itself. The second branch is designed to be substantially flat before assembly, and the act of fixing the second fixing portion to the fixed point causes automatic plastic deformation and fold formation, activating the spring's return function immediately from the first braking application

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the second branch is substantially flat before assembly, then the spring can be easily assembled and installed, but the spring requires deformation during assembly to become active

Engineering Contradiction:
Improveassembly easeVSAvoidassembly deformation process
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The spring performs its own activation during the assembly process. When the second fixing portion is attached to the fixed point, the second branch automatically deforms plastically to form the fold and create the preload, without requiring separate activation steps or additional tools. The assembly process itself activates the spring function

Inventive Principle:
Principle #25Self-service

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 spring is preloaded during assembly, ensuring immediate activation and consistent performance by compensating for wear, maintaining the distance between the brake pad lining and disc, thus preventing residual braking from the first use.

Implementation Method 1

it deforms elastically to return the brake pad to a position rearward relative to the brake disc after a braking phase

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

to deform plastically to compensate for the wear of an assembly formed by the brake disc and a brake pad lining

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

said second branch deforms plastically along a third fold so that the second branch after assembly has two parts in two different planes

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3864317B1Self-adjusting brake pad return spring and method for manufacturing a disc brake comprising such springs
Publication Date: 2022.12.28 HITACHI ASTEMO FRANCE
  • EP3864317B1 patent drawingFigure 1~2
  • EP3864317B1 patent drawingFigure 3~4A
  • EP3864317B1 patent drawingFigure 4B~4C

AI summary

The invention relates to a return spring of a disc brake pad intended to be mounted between the pad and a clevis, intended to compensate for the wear of an assembly formed by the brake disc and a lining of the brake pad, the spring comprising a first attachment portion (12) to the brake pad, a second attachment portion (14) to the clevis, and a third portion (16) connecting the first (12) and second (14) attachment portions, said V-shaped third portion (16) comprising a first branch (24) and a second branch (26) connected by a first fold (P1), in which, prior to assembly, the second branch (26) is planar and such that, when the second attachment portion (14) is attached to the clevis, said second branch (26) plastically deforms along a third fold such that the second branch (26) is no longer planar.