Polyimide Insulated Wire With Filler Aggregates for Surge Resistance
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Solution Overview
Problem
Conventional insulated wires experience dielectric breakdown due to surge resistance issues, with existing solutions not adequately addressing the need for improved surge resistance and resistance to hydrolysis when exposed to Automatic Transmission Fluid (ATF).
Innovation Solution
The insulated wire features a polyimide resin with silica or alumina primary and secondary particles, where the secondary particles have a specific diameter range and occupy a significant area percentage, enhancing surge resistance and incorporating a specific acid dianhydride and diamine compound composition for improved toughness and ATF resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulating materials are used, then manufacturing is simple, but surge resistance is insufficient leading to dielectric breakdown
Solution Approach 1:
The insulating layer uses a composite material consisting of polyimide resin combined with inorganic filler particles (silica or alumina) with specific particle diameter ranges. This composite structure provides both the required surge resistance through the inorganic particles' high dielectric strength and the flexibility of the polyimide matrix, while maintaining manufacturability through a single-layer application process.
Solution Approach 2:
The patent specifies precise parameter ranges for the inorganic filler particles, including particle diameter (0.01-10 μm) and content ratio (1-50 mass%). By optimizing these parameters, the insulating layer achieves maximum surge resistance while controlling manufacturing complexity. The particle size distribution and concentration are carefully controlled to prevent aggregation and ensure uniform electrical properties.
2Reliability
If standard insulating layers are used, then production is straightforward, but resistance to hydrolysis in ATF is insufficient
Solution Approach 1:
The inorganic filler particles (silica or alumina) act as intermediaries between the polyimide resin and the ATF environment. These particles form a barrier layer that prevents direct contact between the resin and hydrolytic agents in the ATF, thereby enhancing chemical resistance. The particles are dispersed throughout the resin matrix to create a tortuous path for hydrolytic attack.
Solution Approach 2:
The insulating layer exhibits local quality enhancement at the particle-resin interfaces, where the inorganic particles create zones of improved chemical stability. The particle distribution is optimized to provide localized protection against hydrolysis while maintaining overall coating integrity and ease of application through conventional dip-coating or spray-coating methods.
3Reliability
If inorganic filler particles are added to improve surge resistance, then dielectric breakdown is suppressed, but manufacturing complexity increases
Solution Approach 1:
The patent defines specific parameter ranges for the inorganic filler particles including particle diameter (0.01-10 μm), particle type (silica or alumina), and content ratio (1-50 mass%). By controlling these parameters, the patent achieves optimal dielectric breakdown resistance while maintaining manageable material composition complexity. The particle size distribution is optimized to balance electrical performance with ease of dispersion and processing.
Data Source
AI summary
An insulated wire comprising a conductor and an insulating layer covering the conductor, wherein: the insulating layer comprises a resin and a first filler; the resin comprises a polyimide; the first filler is present in the form of a primary particle or a secondary particle having a plurality of the primary particles aggregated; the primary particle is a silica or alumina particle; the secondary particle has a particle diameter of 0.03 μm or more and 5 μm or less; and the percentage of the total area of the secondary particles to the sum of the total area of the primary particles and the total area of the secondary particles in the cross section of the insulated wire is 50% or more.