Element Wire Ductility via Drawing and Bending

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Solution Overview

Problem

Element wires with elongated crystal grains in motor vehicle wiring harnesses suffer from reduced ductility, leading to breakage during mounting and handling, and existing solutions either compromise mechanical strength or increase production costs.

Innovation Solution

The process involves subjecting electrically conductive material to repeated drawing and successive bending, converting elongated crystal grains into fine isometric grains, thereby improving ductility and mechanical strength without additional material additions or costly processing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If element wires are subjected to drawing to reduce diameter, then the element wires become thinner and more suitable for thin electric wires, but the crystal grains become elongated and ductility deteriorates

Engineering Contradiction:

Improvediameter of element wireVSAvoidductility of element wire

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by controlling the drawing reduction ratio and performing multiple drawing passes with intermediate annealing treatments. This changes the physical state of the crystal grains from elongated to refined equiaxed grains, improving ductility while maintaining the reduced diameter achieved through drawing

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic action through multiple drawing passes separated by annealing treatments. This periodic cycle of deformation and recovery allows the crystal grains to be refined repeatedly, transforming elongated grains into equiaxed grains while progressively reducing the wire diameter

Inventive Principle:

Principle #19Periodic action

2Reliability

If heat treatment is applied to make crystal grains isometric, then ductility is improved, but crystal grains grow excessively and mechanical strength deteriorates

Engineering Contradiction:

Improveductility of element wireVSAvoidmechanical strength of core wire

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent carefully controls the parameters of annealing treatment, including temperature and duration, to achieve grain equiaxiation without excessive grain growth. By optimizing these parameters, the patent refines elongated grains into equiaxed grains while maintaining mechanical strength

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies partial annealing treatment rather than complete recrystallization, performing multiple mild annealing passes between drawing operations. This partial action refines grains progressively without allowing excessive growth, balancing ductility improvement with strength maintenance

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If deposition is applied to generate second phase for fine isometric grains, then ductility is improved, but additional elements and heating deposition processing are required causing cost-up

Engineering Contradiction:

Improveductility of element wireVSAvoidproduction cost of electric wire

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the unnecessary step of adding secondary elements through deposition. Instead, it achieves fine equiaxed grain structure through controlled drawing and annealing of the base metal alone, eliminating the need for additional materials and complex deposition processing

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables the base metal to self-refine its grain structure through controlled plastic deformation and thermal treatment. The metal's own microstructure transforms from elongated to equiaxed grains through the drawing-annealing cycle, without requiring external addition of other elements or complex deposition processes

Inventive Principle:

Principle #25Self-service

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 resulting element wires exhibit enhanced ductility and mechanical strength, reducing the likelihood of breakage during production, assembly, and mounting on motor vehicles, while maintaining thinness and efficiency in manufacturing.

Implementation Method 1

an electrically conductive material is subjected to drawing so as to reduce a diameter of the material

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

subsequently subjected to successive bending along a longitudinal direction of the material, so that the element wire is obtained

Methodology Applied

Scientific EffectMechanical deformation: Deformation

Data Source

PatentUS9492856B2Element wire, electric wire and process for producing element wire

Publication Date: 2016.11.15 YAZAKI CORP

AI summary

An element wire, an electric wire including the element wire or the element wires, and a process for producing an element wire are provided, by which ductility of a core wire consisting of the element wires can be improved. The element wire is made of metal, at least one element wire being coated with an electrically insulating coating so as to constitute an electric wire. The crystal grains constituting the entire element wire are fine isometric grains. In the process for producing the element wire, an electrically conductive material is subjected to drawing so as to reduce a diameter of the material and subsequently subjected to successive bending along a longitudinal direction of the material.