Terminal-Equipped Wire Resin Cover Adhesion
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Solution Overview
Problem
Existing terminal-equipped electrical wires face corrosion issues due to dissimilar metal corrosion at the electrical connection portion, especially when aluminum or aluminum alloys come into contact with copper-based materials, and the corrosion prevention methods like resin covering fail to maintain adhesion over temperature cycles, leading to detachment and reduced corrosion resistance.
Innovation Solution
A terminal-equipped electrical wire with a resin cover portion that has a tensile shear adhesion strength of 1.0 MPa or higher with the terminal fitting and 0.5 MPa or higher with the insulation covering, utilizing a composite resin structure with a first cover layer made of polyester elastomer or polyurethane elastomer and a second cover layer made of polyester resin, polycarbonate resin, or polyphenylene sulfide resin, ensuring strong adhesion and corrosion resistance across temperature cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin material is used to cover the electrical connection portion for corrosion prevention, then corrosion resistance is improved, but adhesion strength deteriorates under temperature cycles causing detachment
Solution Approach 1:
The patent applies composite materials by combining a thermoplastic polyamide resin base material with a thermoplastic elastomer. This composite structure provides both corrosion resistance from the polyamide resin and flexible adhesion from the elastomer component, allowing the covering to maintain bond strength under temperature cycling conditions while preventing corrosion at the electrical connection portion.
Solution Approach 2:
The patent changes the physical and chemical parameters of the resin material by specifying a coefficient of elongation of 20% or more and a coefficient of water absorption of 6% or less. These parameter adjustments ensure the material can accommodate thermal expansion differences without detaching while maintaining corrosion barrier properties.
2Weight of moving object
If aluminum or aluminum alloy conductors are used for weight reduction, then vehicle weight is reduced, but dissimilar metal corrosion occurs when contacting copper-based terminal fittings
Solution Approach 1:
The patent uses a thermoplastic polyamide resin covering as an intermediary barrier material between the aluminum conductor and copper-based terminal fitting. This intermediate layer physically separates the dissimilar metals, preventing direct contact and the electrochemical reactions that cause dissimilar metal corrosion, while still allowing electrical connection through the crimping process.
3Device complexity
If a single-layer resin covering is used for simplicity, then manufacturing complexity is reduced, but adhesion insufficiently prevents detachment under temperature cycles
Solution Approach 1:
The patent employs a composite material system consisting of a thermoplastic polyamide resin combined with a thermoplastic elastomer in a specific ratio (5-50 parts elastomer per 100 parts polyamide resin). This composite approach enhances adhesion strength without requiring multiple separate layers, maintaining manufacturing simplicity while achieving the required adhesion performance under temperature cycling.
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 composite resin structure maintains high adhesion between the resin cover and both the terminal fitting and insulation covering, preventing detachment and ensuring long-term corrosion resistance even under temperature fluctuations, thus effectively addressing the corrosion issues in vehicle environments.
Implementation Method 1
a resin cover portion 7 made of a resin material 70 is formed so as to cover a portion 6 that includes the electrical connection portion
Implementation Method 2
a tensile shear adhesion strength between the resin cover and the terminal fitting is 1.0 MPa or higher, and a tensile shear adhesion strength between the resin cover and the insulation covering is 0.5 MPa or higher
Data Source
AI summary
A terminal-equipped electrical wire that includes a terminal fitting; an electrical wire that includes a conductor surrounded by an insulation covering and is electrically connected to the terminal fitting in an electrical connection; and a resin cover that is made of a resin material and covers the electrical connection, wherein the resin cover is in contact with the terminal fitting and the insulation covering, a tensile shear adhesion strength between the resin cover and the terminal fitting is 1.0 MPa or higher, and a tensile shear adhesion strength between the resin cover and the insulation covering is 0.5 MPa or higher.