Fretting-Resistant Connector With Organic Ether Coating

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Solution Overview

Problem

Current connectors, especially multi-way connectors for electrical signals in vehicles, face challenges with increased force requirements for insertion due to wear and oxidation of tin plating, leading to reduced fretting resistance and corrosion, and existing solutions do not effectively combine fretting and corrosion resistance simultaneously.

Innovation Solution

A fretting-resistant connector with an organic ether compound coating on electrically conductive metal terminals, specifically using dipropyl ether, allyl phenyl ether, or tetraphenyl ether, applied between 0.0001 µm and 0.1 µm thick, combined with a tin, tin-copper, or tin-silver alloy surface layer, and an intermediate nickel or copper layer, to reduce friction and prevent corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tin plating is applied on metal terminals to improve corrosion resistance, then corrosion resistance is improved, but the tin wears away easily due to vibration causing oxidation and worsening electrical conduction

Engineering Contradiction:
Improvecorrosion resistanceVSAvoiddurability of plating
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies a composite coating structure consisting of multiple layers: a base metal layer, a tin plating layer, and a fluorinated organic coating layer. This composite structure combines the corrosion resistance of tin plating with the wear and oxidation resistance of the fluorinated organic coating, solving the problem of tin wearing away due to vibration while maintaining electrical conduction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition of the organic coating by introducing fluorinated groups (such as CF3 and CF2 groups). This parameter change in the coating's chemical structure enhances its resistance to oxidation and wear, preventing the tin plating from wearing away easily under vibrational conditions while maintaining the desired corrosion protection.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple male and female terminals are designed to be inserted simultaneously in a multi-way connector, then connectivity is improved, but the insertion force becomes too large requiring special tools

Engineering Contradiction:
Improvemulti-way connectivityVSAvoidinsertion force
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The patent changes the friction characteristics of the terminal surfaces by applying a fluorinated organic coating with low surface energy. This parameter change in surface properties reduces the coefficient of friction between mating terminals, thereby reducing the insertion force required for simultaneous multi-way connection while maintaining reliable electrical contact.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If space is reduced between male and female terminals to maintain compact design, then size is reduced, but insertion force increases and fretting resistance decreases

Engineering Contradiction:
Improveconnector sizeVSAvoidfretting resistance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs a composite coating system that includes a fluorinated organic coating layer over the tin plating. This composite structure provides enhanced fretting resistance through the durable fluorinated outer layer, allowing reduced spacing between terminals while maintaining reliability even under compact dimensions.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The fluorinated organic coating changes the tribological parameters of the terminal surface, providing low friction and high wear resistance. This parameter change enables the connector to maintain fretting resistance with reduced terminal spacing, as the coating protects against wear and oxidation in the tighter configuration.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If surface active agents are applied to improve solder wettability, then wettability is improved, but the agents bind to moisture and acidic substances causing discoloration and corrosion

Engineering Contradiction:
Improvesolder wettabilityVSAvoiddiscoloration and corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite coating structure where the fluorinated organic coating layer is applied over the tin plating. This composite approach provides solder wettability through the fluorinated groups while the stable fluorocarbon backbone resists binding to moisture and acidic substances, preventing discoloration and corrosion that plague traditional surface active agents.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition of the organic coating by introducing fluorinated groups (CF3 and CF2) which provide both solder wettability and resistance to environmental degradation. This parameter change in chemical composition allows the coating to maintain wettability without the harmful side effects of conventional surface active agents.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces the force required for insertion while enhancing fretting and corrosion resistance, maintaining electrical conductivity and preventing oxidation, even under vibration and temperature variations.

Implementation Method 1

wherein the organic coating is provided into the tin, the tin-copper alloy, the tin-silver alloy, or the tin-silver-copper alloy with adsorption of the organic coating

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

there becomes easier for such the tin that is plated on a surface thereof to be worn away as easily and then to be oxidized due to a slight vibration thereon

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Data Source

PatentEP2173012B1Fretting-resistant connector and process for manufacturing the same
Publication Date: 2019.04.17 FURUKAWA ELECTRIC CO LTD
  • EP2173012B1 patent drawingFigure 1~3
  • EP2173012B1 patent drawingFigure 4~5

AI summary

A fretting-resistant connector, having an organic coating that is formed of an organic compound which has an ether linkage group at least a part on a surface of an electrically conductive metal material.