Silver-Graphite Grounding Brush for Stable Axle Noise Suppression
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Solution Overview
Problem
Existing grounding brushes for electric and hybrid vehicles are ineffective in reducing electro-magnetic noise from the driving axle, particularly affecting car radios, due to high resistance and unstable contact resistance, and do not efficiently ground the inverter.
Innovation Solution
A metal graphite grounding brush with a composition of 30-90% silver, 10-70% carbonaceous components, and 2-15% volatile components, configured for slide contact with the axle, reduces electro-magnetic noise by maintaining low resistivity and stable contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver content is increased to reduce resistance, then electro-magnetic noise grounding improves, but manufacturing cost increases
Solution Approach 1:
The patent optimizes the silver content parameter to a specific range (30-90 mass%) rather than using pure silver or low silver content materials. This parameter optimization achieves the dual benefit of sufficient grounding effectiveness (low resistance) and cost control, resolving the contradiction between reliability and manufacturing cost
Solution Approach 2:
The patent creates a composite grounding brush material combining silver particles with carbonaceous components (graphite and volatile components). This composite structure leverages the high conductivity of silver and the lubricating properties of carbon, achieving effective grounding while reducing material cost compared to pure silver
2Duration of action of stationary object
If silver content is increased to maintain low resistivity, then service life improves, but manufacturing cost increases
Solution Approach 1:
The composite structure of silver and carbonaceous components provides both electrical conductivity and mechanical durability. The carbonaceous components contribute to brush strength and wear resistance, extending service life while keeping manufacturing costs manageable through optimized silver content (30-90 mass%)
Solution Approach 2:
The patent specifies optimal ranges for silver content (30-90 mass%), carbonaceous components (10-70 mass%), and volatile components (2-15 mass%) to achieve the best balance between service life and manufacturing cost. These parameter optimizations ensure long service life without requiring excessive silver content
3Ease of manufacture
If carbonaceous components are increased to reduce cost, then manufacturing cost decreases, but contact resistance becomes unstable
Solution Approach 1:
The patent defines a specific range for carbonaceous components (10-70 mass%) to maintain stable contact resistance. Within this range, the carbonaceous components provide adequate lubrication and structural support without compromising electrical contact stability, achieving cost reduction while maintaining reliability
Solution Approach 2:
The composite of silver and carbonaceous components creates a material where silver ensures low and stable contact resistance while carbonaceous components provide structural integrity and lubrication. This synergistic combination allows cost-effective manufacturing without sacrificing contact resistance stability
4Strength
If volatile component content is optimized, then brush strength improves, but manufacturing complexity increases
Solution Approach 1:
The patent specifies an optimal range for volatile components (2-15 mass%) that enhances brush strength through controlled binding and structural formation. This parameter specification achieves improved strength without requiring complex manufacturing processes, as the volatile components are incorporated during standard brush fabrication
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 brush effectively reduces electro-magnetic noise, extending service life and maintaining low noise levels in vehicle audio equipment by optimizing silver and carbonaceous content and volatile component ratios.
Implementation Method 1
a mass composition in the brush main body between silver and carbonaceous components including graphite and a volatile component is silver more than 30 mass% and not more than 90 mass% and the carbonaceous components less than 70 mass% and not less than 10 mass%
Data Source
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AI summary
The metal graphite grounding brush including silver is made in slide contact with a peripheral surface of an axle and grounds the axle. The mass ratio between silver and carbonaceous components including a volatile component in the brush is silver above 30 % and up to 90 % and carbonaceous components less than 70 % and down to 10 %. When the total of silver and carbonaceous components is made 100 %, the volatile component is down to 2.0 % and up to 15 %. The brush grounds the axle reliably so that noise from a car radio is reduced and has a long service life and mechanical strength.