Insulated Copper Wire Structure for Heat Resistance and Flexibility

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Solution Overview

Problem

Insulated wires used in high-performance electrical equipment, such as electric vehicle generators, face challenges with space factor improvement, brittle corners during processing, insulation damage, and insufficient heat resistance under high temperatures.

Innovation Solution

Utilizing high-purity oxygen-free copper (OFC) with a specific composition and texture as the conductor, combined with a resin layer, to enhance electrical conductivity and heat resistance, and incorporating a foamed insulating layer to withstand vibrations and maintain insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple layers of insulation are applied to achieve high voltage resistance, then voltage resistance is improved, but the wire diameter increases and flexibility deteriorates

Engineering Contradiction:
Improvevoltage resistanceVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies composite materials by combining multiple insulation layers with different material properties. The first insulation layer uses a material with high dielectric strength for voltage resistance, while the second insulation layer uses a material with different mechanical properties to maintain flexibility. This composite structure allows the wire to achieve both high voltage resistance and adequate flexibility simultaneously.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the wire diameter is reduced to improve flexibility, then flexibility is improved, but the number of insulation layers must be reduced which worsens voltage resistance

Engineering Contradiction:
ImproveflexibilityVSAvoidvoltage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by assigning different material compositions and thicknesses to different insulation layers. The first insulation layer near the conductor has optimized properties for electrical performance, while the second outer insulation layer has optimized properties for mechanical flexibility. This localized optimization allows the wire to maintain both flexibility and voltage resistance without compromising either property.

Inventive Principle:
Principle #3Local quality

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 insulated wire achieves improved heat resistance and electrical conductivity, enabling higher performance and miniaturization of electric equipment while preventing insulation damage and maintaining mechanical strength.

Implementation Method 1

a first insulation layer comprising a fluororesin composition, in which 5 wt % or more but not more than 20 wt % of fluororesin is represented by a polytetrafluoroethylene homopolymer

Methodology Applied
Scientific EffectDielectric strength: Dielectric

Implementation Method 2

the wire has high flexibility and feels soft to the touch, while maintaining heat resistance and insulation performance

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3739599B1Insulated wire
Publication Date: 2026.04.22 ESSEX FURUKAWA MAGNET WIRE JAPAN CO LTD
  • EP3739599B1 patent drawingFigure 1(A)~1(B)
  • EP3739599B1 patent drawingFigure 2~3
  • EP3739599B1 patent drawing

AI summary

An insulated wire (10) of the present invention includes: a copper alloy conductor (1); and at least one resin layer (4) directly or indirectly coated on an outer peripheral face of the copper alloy conductor (1). The copper alloy conductor (1) has a composition where a total content of metal components selected from Al, Be, Cd, Mg, Pb, Ni, P, Sn, and Cr is from 0.1 to 2.0 ppm and content of copper is 99.96 mass% or higher, and has a texture where when a crystal orientation distribution function obtained from texture analysis by EBSD is expressed using Euler angles (ϕ1, Φ, and ϕ2), an average orientation density in an area where ϕ2 = 0 degrees, ϕ1 = 0 degrees, and Φ = from 0 degrees to 90 degrees is from 3.0 to less than 35.0, and a maximum orientation density in an area where ϕ2 = 35 degrees, ϕ1 = from 45 degrees to 55 degrees, and Φ = from 65 degrees to 80 degrees is from 1.0 to less than 30.0.