Stranded Conductor With Ni-Plated Copper for High-Temperature Oil Corrosion

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Solution Overview

Problem

Conventional stranded wire conductors used in high-temperature oils, such as ATF and CVT fluids, face corrosion issues due to sulfur components, leading to deterioration in strength and electric conductivity, especially in small-diameter wires where Sn-plated layers melt during heat treatment, compromising corrosion resistance.

Innovation Solution

A stranded wire conductor with a Ni-based plated layer on copper-based element wires, combined with a tension member like stainless steel, is subjected to circular compression and heat treatment, ensuring the Ni-based layer maintains integrity and prevents corrosion in high-temperature oils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a Sn plated layer is formed on the surface of the bare copper element wire to prevent corrosion, then corrosion resistance is improved, but the plated layer melts during heat treatment and falls away, deteriorating reliability

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidintegrity of plated layer
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the material parameter of the plated layer from Sn to Ni-based material. Ni has a melting point of approximately 1455°C, which is significantly higher than the heat treatment temperature for softening copper (typically 200-400°C). This parameter change ensures the plated layer maintains its integrity during heat treatment while providing corrosion resistance in high-temperature oil environments.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure consisting of a Ni-based plated layer on the copper element wire surface. This composite material combines the excellent electrical conductivity of copper with the high melting point and corrosion resistance of Ni-based materials, achieving both electrical performance and environmental stability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If heat treatment is performed to soften copper after circular compression, then elongation is improved, but the plated layer may melt and fall away, deteriorating strength

Engineering Contradiction:
ImproveelongationVSAvoidstrength of plated layer
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The patent changes the material parameter of the plated layer from Sn to Ni-based material. Ni has a melting point of approximately 1455°C, which is significantly higher than the heat treatment temperature for softening copper (typically 200-400°C). This parameter change ensures the plated layer maintains its integrity during heat treatment while providing corrosion resistance in high-temperature oil environments.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If bare copper element wires are used to maintain electrical conductivity, then electric conductivity is improved, but corrosion by sulfur component in high-temperature oil deteriorates strength and conductivity

Engineering Contradiction:
Improveelectric conductivityVSAvoidcorrosion by sulfur component
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The Ni-based plated layer serves as an intermediary barrier between the copper element wire and the corrosive high-temperature oil environment containing sulfur components. This intermediate layer protects the copper from direct contact with corrosive agents while maintaining electrical conductivity through the composite structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure consisting of a Ni-based plated layer on the copper element wire surface. This composite material combines the excellent electrical conductivity of copper with the high melting point and corrosion resistance of Ni-based materials, achieving both electrical performance and environmental stability.

Inventive Principle:
Principle #40Composite materials

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 Ni-based plated layer provides superior corrosion resistance and maintains the strength and conductivity of the stranded wire conductor even in high-temperature oils, while the tension member enhances tensile resistance, effectively preventing disconnection and corrosion.

Implementation Method 1

the Ni-based plate has a higher melting point, compared to a Sn plate. Further, the melting point of the Ni-based plate is higher than the softening temperature of a copper material composing the copper-based element wire

Methodology Applied
Scientific EffectCorrosion resistance:

Implementation Method 2

the bare copper element wires were subjected to heat treatment so as to improve the elongation which was deteriorated by work-hardening after the bare copper element wires were twisted together and subjected to circular compression

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

a tension member like stainless steel, is subjected to circular compression and heat treatment, ensuring the Ni-based layer maintains integrity and prevents corrosion in high-temperature oils

Methodology Applied
Scientific EffectTensile resistance:

Data Source

PatentEP3113190B1Stranded conductor and insulated wire
Publication Date: 2020.04.22 AUTONETWORKS TECH LTD
  • EP3113190B1 patent drawingFigure 1~2

AI summary

A stranded wire conductor 1 includes a plurality of copper-based element wires 20 which are twisted together, and is subjected to circular compression and then heat treatment. The copper-based element wires 20 have a Ni-based plated layer on the surface. The stranded wire conductor 1 preferably has a conductor cross-sectional area of 0.25 mm2 or less. An insulated wire 5 includes the stranded wire conductor 1, and an insulator 4 that coats the outer circumference of the stranded wire conductor 1.