Three-Layer Insulated Wire for Coil Winding
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Solution Overview
Problem
Insulated wires with small diameters face challenges in maintaining high voltage resistance, processing resistance, and flexibility, especially under severe environmental conditions such as high humidity and high temperature, and when subjected to severe 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, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, and pyromellitic anhydride with 4,4′-diaminodiphenyl ether, enhancing environmental atmosphere resistance, processing resistance, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the enameled wire is reduced to further miniaturize the coil, then the space factor of the enameled wire is improved, but the processing resistance deteriorates due to more severe processing stress during coiling
Solution Approach 1:
The patent applies a composite insulating film structure consisting of multiple layers with different material compositions and properties. The first layer uses a polyamideimide resin with specific flexibility characteristics, the second layer uses a different polyamideimide resin with enhanced processing resistance, and the third layer uses a polyimide resin with superior environmental atmosphere resistance. This composite structure allows each layer to contribute its specific strengths, enabling the wire to maintain high processing resistance even when miniaturized, while the overall structure remains flexible enough for coil winding.
2Temperature
If an insulating varnish containing highly-adhesive polyesterimide or highly-adhesive polyamideimide is applied and an aromatic polyamide film is formed, then heat resistance and heat deterioration resistance are improved, but flexibility and processing resistance become insufficient
Solution Approach 1:
The patent segments the insulating film into three distinct layers, each with specific functional assignments. The first layer (polyamideimide resin) provides flexibility and basic adhesion. The second layer (different polyamideimide resin) provides enhanced processing resistance and intermediate bonding. The third layer (polyimide resin) provides superior heat resistance and environmental atmosphere resistance. This segmentation allows each layer to optimize its specific function without compromising the overall performance, resolving the contradiction between heat resistance and flexibility.
3Device complexity
If a single-layer insulating film is used, then the device complexity is reduced, but the environmental atmosphere resistance deteriorates under severe conditions such as high humidity and high temperature
Solution Approach 1:
The patent employs a composite three-layer insulating film structure where each layer is made of specifically formulated resins with complementary properties. The first layer provides adhesion and flexibility, the second layer enhances processing resistance and intermediate bonding, and the third layer provides superior environmental atmosphere resistance including resistance to high humidity, high temperature, and oil contact. This composite structure achieves high environmental atmosphere resistance that would be difficult to obtain with a single-layer film, while the layered design remains manageable in the manufacturing process.
4Productivity
If the insulating film is made thinner to reduce coil size, then the productivity is improved, but the voltage resistance deteriorates
Solution Approach 1:
The patent uses a composite three-layer insulating film structure that achieves high voltage resistance even when the total film thickness is reduced. The first layer (polyamideimide resin) provides good adhesion and flexibility with adequate dielectric properties. The second layer (different polyamideimide resin) provides enhanced processing resistance and intermediate dielectric strength. The third layer (polyimide resin) provides superior environmental atmosphere resistance and excellent dielectric strength. The synergistic combination of these three layers maintains high voltage resistance while allowing for thinner overall film thickness, enabling coil miniaturization without compromising electrical safety.
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 voltage resistance, processing resistance, flexibility, and heat resistance, preventing deterioration of insulating characteristics even under severe conditions, and ensuring the wire remains intact during coil winding.
Implementation Method 1
a first layer of a first polyamideimide containing an adhesion improver
Implementation Method 2
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 3
a third layer of a polyimide disposed on the second layer, the polyimide being obtained by reacting an acid component containing 50 to 90 mol % of 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, 5 to 20 mol % of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 5 to 40 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 90 mol % of 3,3′,4,4′-biphenyl tetracarboxylic dianhydride, 5 to 20 mol % of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride and 5 to 40 mol % of pyromellitic anhydride with a diamine component containing 4,4′-diaminodiphenyl ether.