Three-Layer Insulated Wire for High Voltage Resistance
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Solution Overview
Problem
Insulated wires with rectangular cross sections face challenges in maintaining high voltage resistance, processing resistance, and flexibility, especially when miniaturized and exposed to severe environments such as high humidity and oil contact, due to insufficient environmental atmosphere resistance and processing stress during coil winding.
Innovation Solution
A three-layer insulating film structure is applied to the conductor, comprising a first layer of highly-adhesive polyamideimide, a second layer of highly-flexible polyamideimide obtained by reacting isocyanate components like 2,4′-diphenylmethane diisocyanate and dimer acid diisocyanate, and a third layer of polyimide formed by reacting 3,3′,4,4′-biphenyl tetracarboxylic dianhydride and pyromellitic anhydride with 4,4′-diaminodiphenyl ether, enhancing adhesion, flexibility, and environmental resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer insulating film is used, then the structure is simple, but the environmental atmosphere resistance and processing resistance are insufficient
Solution Approach 1:
The insulating film is divided into three distinct layers, each with specific thickness and material composition. The first layer (20-40 μm) provides adhesion, the second layer (40-80 μm) provides flexibility and processing resistance, and the third layer (20-40 μm) provides environmental atmosphere resistance. This segmentation allows each layer to specialize in one function, achieving superior overall performance compared to a single-layer structure.
Solution Approach 2:
The patent uses composite material composition across the three layers, with each layer containing specific ratios of polyamideimide, polyesterimide, and polyamide components. The composite structure combines the advantages of different materials: polyamideimide for adhesion and flexibility, polyesterimide for heat resistance, and polyamide for environmental resistance, creating a synergistic effect that exceeds the sum of individual layer performances.
2Productivity
If the diameter of the enameled wire is made smaller for miniaturization, then the space factor is improved, but the processing resistance becomes insufficient due to severe processing stress
Solution Approach 1:
The patent optimizes the thickness parameters of each layer relative to the wire diameter. For smaller diameter wires, the absolute thickness of each layer is reduced proportionally, but the relative thickness ratios are maintained. Additionally, the chemical composition parameters are adjusted within specified ranges to enhance flexibility and adhesion, allowing the insulating film to withstand the severe processing stress encountered during coil winding of miniaturized wires.
Solution Approach 2:
The insulating film is designed with enhanced flexibility through the second layer containing 60-80 mass% polyamideimide, which provides excellent flexibility and elongation properties. This flexible thin film structure can accommodate the severe deformation and bending stresses that occur during the coil winding process, preventing cracking and peeling even in miniaturized wires with small diameters.
3Reliability
If highly-adhesive polyesterimide or polyamideimide is used to improve heat resistance, then heat deterioration resistance is improved, but flexibility and processing resistance become insufficient
Solution Approach 1:
The insulating film is segmented into three layers with different material compositions optimized for specific functions. The first layer contains polyesterimide and polyamideimide for adhesion and heat resistance. The second layer is dominated by polyamideimide (60-80 mass%) to provide flexibility and processing resistance. The third layer contains polyamide for environmental atmosphere resistance. This segmentation allows heat resistance and flexibility to be optimized in different layers simultaneously, resolving the contradiction.
Solution Approach 2:
The patent employs composite materials across the three layers, combining polyesterimide, polyamideimide, and polyamide in specific ratios. The polyamideimide component provides both heat deterioration resistance and flexibility, while the polyesterimide contributes to adhesion and heat resistance. The polyamide layer adds environmental atmosphere resistance. This composite material approach allows the insulating film to simultaneously achieve heat resistance, flexibility, and environmental resistance that would be impossible with a single material.
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 solution provides superior environmental atmosphere resistance, processing resistance, flexibility, heat resistance, and heat deterioration resistance, ensuring higher voltage resistance and improved performance under severe conditions without compromising miniaturization or mechanical strength.
Implementation Method 1
a second layer of a second polyamideimide disposed on the first layer, the second polyamideimide being obtained by reacting an isocyanate component containing 10 to 70 mol % in total of 2,4′-diphenylmethane diisocyanate and dimer acid diisocyanate with an acid component
Implementation Method 2
a third layer of a polyimide disposed on the second layer, the polyimide being obtained by reacting an acid component containing 50 to 80 mol % of 3,3′,4,4′-biphenyl tetracarboxylic dianhydride and 20 to 50 mol % of pyromellitic anhydride with a diamine component containing 4,4′-diaminodiphenyl ether
Data Source
AI summary
According to one embodiment, an insulated wire is disclosed. The wire includes a conductor and an insulating film formed on the conductor, the insulating film including a first layer of a first polyamideimide containing an adhesion improver; a second layer of a second polyamideimide obtained by reacting an isocyanate component containing 10 to 70 mol % in total of 2,4′-diphenylmethane diisocyanate and dimer acid diisocyanate with an acid component; and a third layer of a polyimide obtained by reacting an acid component containing 50 to 80 mol % of 3,3′,4,4′-biphenyl tetracarboxylic dianhydride and 20 to 50 mol % of pyromellitic anhydride with a diamine component containing 4,4′-diaminodiphenyl ether.