Vehicle Starter Brush Holder Elastic Retention Tabs

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Solution Overview

Problem

The existing brush holder configurations for vehicle starters tend to break at their fasteners due to severe vibrations and thermal expansion, leading to connector failure.

Innovation Solution

The brush holder design incorporates cages with axial tabs to retain the inter-brush connector through elastic deformation, providing additional fulcrums for improved locking and using an insulating element to prevent short-circuits, while optimizing material usage and mechanical retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the inter-brush connector is fixed by soldering or crimping to brush cages, then the connector is mechanically retained, but the connector breaks at its fasteners due to severe vibrations and thermal expansion

Engineering Contradiction:

Improvemechanical retention of connectorVSAvoidconnector fastener durability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the retention mechanism from rigid soldering or crimping to elastic deformation. The inter-brush connector is designed to be retained by elastic deformation against the brush cage legs, allowing the connector to flex and absorb vibrations and thermal expansion without breaking at the fasteners.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The inter-brush connector is designed with flexible properties, allowing it to deform elastically under vibration and thermal expansion. This flexibility enables the connector to maintain mechanical retention while accommodating dynamic environmental conditions without fastener failure.

Inventive Principle:

Principle #30Flexible shells and thin films

2Stability of the object's composition

If the connector is rigidly fixed to the brush cages, then the connector is stable, but the connector cannot absorb thermal expansion variations

Engineering Contradiction:

Improveconnector position stabilityVSAvoidthermal expansion accommodation

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a rigid fixed connection to a dynamic elastic retention system. The connector is held by elastic deformation against the brush cage legs, allowing it to dynamically adapt to thermal expansion and contraction while maintaining stable positioning through the elastic restoring force.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent converts the harmful effect of thermal expansion into a beneficial elastic deformation. Instead of rigidly resisting thermal expansion (which causes stress and failure), the connector is designed to elastically deform under thermal loads, absorbing the expansion variations while maintaining stable connection.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If soldering or crimping is used to fix the connector, then the connection is strong, but the connection fails under vibratory environment

Engineering Contradiction:

Improveconnection strengthVSAvoidvibration-induced failure

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the connection method from rigid soldering or crimping to elastic deformation retention. This parameter change allows the connection to maintain strength while accommodating vibratory movements through elastic flexibility, preventing vibration-induced fastener failure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The elastic deformation acts as an intermediary mechanism between the connector and the brush cages. Instead of direct rigid bonding (soldering/crimping), the elastic retention allows relative movement and energy absorption, mediating the vibratory forces and preventing their transmission to the fasteners.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration effectively resists vibrations, absorbs thermal expansion, and maintains connector position, preventing breakage and ensuring reliable electrical contact.

Implementation Method 1

said inter-brush connector is held by elastic deformation against the brush cages tabs

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

an insulating element positioned around a part of said inter-brush connector so as to provide insulation between the cage housing the third brush and said inter-brush connector

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP3066750B1Brush holder of an electric machine for a vehicle and corresponding starter

Publication Date: 2020.09.09 VALEO EQUIP ELECTRIC MOTEUR

Figure 1~3
Figure 4~5b

AI summary

The invention relates mainly to a brush holder (1) of a rotary electric machine comprising at least two boxes (3.1, 3.3) which are each used respectively as a housing for a brush (5.1, 5.3), and an inter-brush connector (20) to which braids (17.1, 17.3) of said brushes (5.1, 5.3) with the same polarity are intended to be welded, the brush holder being characterised in that said boxes (3.1, 3.3) are each provided with at least one tab (25) extending axially relative to an axis of the brush holder (1), and in that said inter-brush connector (20) is held by resilient deformation against the tabs (25) of the brush boxes (3.1, 3.3). The invention also relates to the corresponding starter.