Terminal-Equipped Wire Resin Coating Stress Dispersion

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Solution Overview

Problem

Terminal-equipped wires with resin-coated portions face issues of peeling and cracking under bending stress, which can lead to corrosion due to the concentration of stress and reduced resin thickness at the end portions.

Innovation Solution

A terminal-equipped wire design featuring a resin-coated portion with a thin-walled section of reduced thickness, preferably in a polygonal shape with thicker corner portions, and a tapered structure that narrows towards the center, ensuring sufficient resin thickness and stress dispersion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the end portion of the resin-coated portion has a steeply rising shape, then the resin coating provides good protection at the end portion, but bending stress causes stress concentration leading to peeling of the coating resin from the wire

Engineering Contradiction:

Improveprotection against corrosionVSAvoidresistance to peeling under bending stress

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies curvature by replacing the steeply rising shape with a gradually rising curved shape at the end portion of the resin-coated region. This curved transition reduces stress concentration points while maintaining protective coverage, preventing peeling under bending stress while preserving corrosion protection.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the resin-coated portion by specifying a gradual rise angle between 5-45 degrees instead of a steep rise. This parameter modification optimizes the balance between protective coverage and stress distribution, preventing both peeling and maintaining corrosion resistance.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the resin thickness is reduced at the end portion, then flexibility and stress dispersion improve, but the strength and protection capability decrease

Engineering Contradiction:

Improveflexibility under bendingVSAvoidprotection against corrosion

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The curved gradual rise shape distributes bending stresses along a longer transition zone rather than concentrating them at a sharp corner. This curvature allows the resin coating to flex with the wire while maintaining protective thickness, achieving both flexibility and corrosion protection simultaneously.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS10290957B2Terminal-equipped wire and wire harness with resin coating on terminal fitting

Publication Date: 2019.05.14 AUTONETWORKS TECH LTD

AI summary

A terminal-equipped wire includes a wire with a core wire and an insulating coating with which the core wire is coated, and a terminal fitting that is attached to a leading end of the wire. The terminal fitting is electrically connected to the core wire in a core-wire crimp portion, and is fixed to the wire from an external side of the insulating coating in a coating crimp portion that is located rearward of the core-wire crimp portion in a longitudinal direction of the wire. The terminal-equipped wire also includes a resin-coated portion where a region containing the core-wire crimp portion and the coating crimp portion is coated with a resin. The resin-coated portion has a thin-walled portion with a reduced thickness, in a portion of the resin-coated portion that covers the insulating coating.