Starter-Generator Brush Lead Butterfly Routing

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Solution Overview

Problem

In starter-generator brushes, the bulky brush leads often become frayed and hang up on the brush box, inhibiting the movement of carbon blocks due to their location between the brush springs, leading to mechanical issues.

Innovation Solution

The design features a dual wafer carbon block configuration where brush leads converge towards a mirror image line, spreading them out to reduce bulkiness and prevent rubbing against the brush box, with outboard leads forming a butterfly shape to minimize friction and fraying.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If brush leads are located between the brush springs to connect carbon blocks to terminal lug, then electrical connection is achieved, but the leads become bulky and rub on the brush box causing fraying and mechanical inhibition

Engineering Contradiction:
Improvebrush lead durabilityVSAvoidbrush lead arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dimensionality change by transitioning the brush lead arrangement from a two-dimensional planar layout (between springs) to a three-dimensional spatial configuration (butterfly shape). The leads extend laterally outward from the carbon block and converge toward the terminal lug, utilizing the third dimension to achieve separation and reduced bulkiness while maintaining electrical connection reliability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If brush leads are bulky to ensure adequate current carrying capacity, then electrical connection is reliable, but they rub on the brush box and become frayed

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidfraying and rubbing
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the problematic interaction between brush leads and brush box by repositioning the leads into a butterfly configuration. This spatial separation removes the leads from the harmful rubbing environment while maintaining their current carrying capacity through optimized routing that minimizes contact with surrounding components

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If brush leads are positioned between brush springs for structural support, then mechanical stability is provided, but movement of carbon blocks is inhibited when leads fray

Engineering Contradiction:
Improvebrush structure stabilityVSAvoidcarbon block movement
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent applies dynamics by creating a flexible butterfly-shaped lead configuration that can adapt its position during carbon block movement. The leads maintain structural stability through their converged routing to the terminal lug while allowing dynamic adjustment during operation, preventing mechanical inhibition when carbon blocks move within the brush box

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3271976B1Starter-generator brush
Publication Date: 2020.01.29 SAFRAN ELECTRICAL & POWER
  • EP3271976B1 patent drawingFigure 1
  • EP3271976B1 patent drawingFigure 2~3
  • EP3271976B1 patent drawingFigure 4~5

AI summary

A brush for a starter-generator includes a first carbon block, a second carbon block, a terminal lug, and a plurality of brush leads. Each carbon block has an outboard edge and an inboard edge. Each carbon block includes a front carbon wafer and a rear carbon wafer. Front brush leads connect the terminal lug with the front carbon wafers of the respective carbon blocks adjacent the inboard edges of the respective carbon blocks. Rear brush leads connect the terminal lug with the rear carbon wafers of the respective carbon blocks adjacent the outboard edge of the respective carbon blocks.