Shielded Wire Sheath Composition for High-Temperature Flexibility
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Solution Overview
Problem
Existing shielded electric wires do not adequately consider the flexibility of the sheath itself, which can lead to reduced overall flexibility and increased distortion when bent, especially when the sheath contracts at high temperatures.
Innovation Solution
A shielded electric wire design where the flexible value of the sheath is equal to or less than that of the electric wire assembly, using a sheath made of insulating resin with a specific occupancy rate to prevent sticking and maintain flexibility, and incorporating a braided conductive material with high-strength fibers for enhanced flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner diameter of the sheath is optimized to improve flexibility, then the overall flexibility of the shielded electric wire is improved, but the flexibility of the sheath itself is not considered, leading to potential hardening and sticking at high temperatures
Solution Approach 1:
The patent applies parameter changes by specifying that the flexible value of the sheath must be equal to or smaller than the flexible value of the electric wire assembly. This parameter constraint ensures the sheath maintains appropriate flexibility relative to the assembly while preventing excessive softness that could cause sticking at high temperatures. The flexible value is defined as a load required for bending an object for a predetermined extent, providing a quantitative measure to control sheath properties.
Solution Approach 2:
The sheath is constructed as a composite material comprising a thermoplastic elastomer and a thermoplastic resin. This composite structure combines the flexibility benefits of elastomers with the thermal stability of thermoplastic resins, resolving the contradiction between needing flexibility for ease of operation and thermal stability for reliability. The specific combination allows the sheath to remain flexible at operating temperatures while resisting hardening and sticking.
2Ease of operation
If the sheath is made softer to improve flexibility, then bending becomes easier, but the sheath may harden and stick to the electric wire assembly at high temperatures
Solution Approach 1:
The patent uses parameter changes by defining specific constraints on the flexible value of the sheath relative to the electric wire assembly. By setting the sheath's flexible value to be equal to or smaller than that of the assembly, the patent prevents the sheath from being excessively soft, which would cause sticking at high temperatures, while still ensuring adequate flexibility for bending operations.
Solution Approach 2:
The composite material structure of the sheath (thermoplastic elastomer + thermoplastic resin) resolves the contradiction between bending ease and preventing sticking. The thermoplastic elastomer component provides the necessary flexibility and softness for easy bending, while the thermoplastic resin component maintains thermal stability and prevents hardening-induced sticking at elevated temperatures.
3Reliability
If the sheath is made stiffer to prevent sticking, then thermal stability is improved, but overall flexibility of the shielded electric wire is reduced
Solution Approach 1:
The patent applies parameter changes by establishing a specific relationship between the flexible value of the sheath and the flexible value of the electric wire assembly. This parameter control ensures the sheath is not excessively stiff, maintaining adequate flexibility for the assembly while still providing sufficient thermal stability to prevent sticking.
Solution Approach 2:
The composite material composition (thermoplastic elastomer and thermoplastic resin in specific proportions) resolves the contradiction between thermal stability and flexibility. The material combination allows the sheath to maintain appropriate stiffness for thermal stability without becoming so rigid that it compromises the overall flexibility of the shielded electric wire assembly.
Data Source
AI summary
A shielded electric wire includes an electric wire including a conductor portion and a cover portion covering the conductor portion, a shielded braid formed of a conductive linear material, the shielded braid covering an outer periphery of the cover portion and a sheath formed of an insulating resin, the sheath being provided around the shielded braid. The electric wire and the shielded braid together form an electric wire assembly. A flexible value of the sheath is equal to or smaller than a flexible value of the electric wire assembly, the flexible value being a value of a load required for bending an object for a predetermined extent.