Rectangular Insulated Wire Coating for Flex Crack and ATF Resistance
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Solution Overview
Problem
Existing insulated wires for electric generators in vehicles face challenges with flex resistance reliability, adhesion between insulating layers, and resistance to Automatic Transmission Fluid (ATF), leading to cracks and reduced electrical characteristics.
Innovation Solution
A rectangular insulated wire configuration with multiple thermoplastic resin layers on a thermosetting resin layer, controlling adhesion strength between 50 gf/mm to 100 gf/mm, and optimizing relative crystallinity to prevent cracks and enhance ATF resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an amorphous resin layer (PES) is formed on the enameled wire to improve insulating properties and long-term heat resistance, then insulating property and heat resistance are improved, but chemical resistance deteriorates causing cracks when immersed in impregnating varnish
Solution Approach 1:
The patent uses a composite resin layer combining amorphous resin (PES) and crystalline resin (PPS or PEEK) in specific weight ratios (PES: 30-95 wt%, crystalline resin: 5-70 wt%). This composite structure provides both the excellent insulating properties and long-term heat resistance of amorphous resin, while the crystalline resin component improves chemical resistance to impregnating varnish, preventing cracks during immersion and curing.
2Object-affected harmful factors
If a crystalline resin layer (PPS or PEEK) is added on the amorphous resin layer to improve chemical resistance, then chemical resistance is improved, but flexibility and resistance to thermal softening deteriorate
Solution Approach 1:
The patent creates a composite resin layer where amorphous resin (PES) and crystalline resin (PPS or PEEK) are combined in specific weight ratios. The amorphous resin component maintains flexibility and resistance to thermal softening, while the crystalline resin provides improved chemical resistance. This balanced composite structure prevents the deterioration of flexibility that would occur with pure crystalline resin coating.
Solution Approach 2:
The patent controls the weight ratio parameters of amorphous resin to crystalline resin (PES: 30-95 wt%, crystalline resin: 5-70 wt%) to optimize the balance between chemical resistance and flexibility. By adjusting these compositional parameters, the coating achieves sufficient chemical resistance while maintaining the flexibility and thermal softening resistance required for wire bending and assembly operations.
3Strength
If a polymer alloy of PES and PPS or PES and PEEK is used to improve adhesion between layers, then adhesion is improved, but flex resistance reliability deteriorates due to crack occurrence
Solution Approach 1:
The patent uses a composite resin layer with amorphous resin (PES) and crystalline resin (PPS or PEEK) in optimized weight ratios rather than a polymer alloy. This composite structure provides sufficient adhesion between the coating layers while maintaining flex resistance reliability, preventing cracks during bending operations that occur with polymer alloy formulations.
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 achieves improved flex resistance reliability, prevents cracks, and provides excellent chemical and scratch resistance, including ATF resistance, while maintaining flexibility and thermal softening properties.
Implementation Method 1
an adhesion strength between the thermosetting resin layer and the thermoplastic resin layer
Implementation Method 2
excellent chemical and scratch resistance, including ATF resistance
Data Source
Figure 1A~1B
AI summary
Provided is a rectangular insulated wire having an improved flex resistance property by achieving both an improvement in adhesion between insulating layers and prevention of occurrence of a crack reaching a conductor, while maintaining flexibility and resistance to thermal softening, and further having an excellent AFT-resistant property. A rectangular insulated wire (1) is provided with a rectangular conductor (2) having a generally rectangular cross section, a thermosetting resin layer (3) formed to cover the rectangular conductor, a thermoplastic resin layer (4) formed to cover the thermosetting resin layer, and a thermoplastic resin layer (5) formed to cover the thermoplastic resin layer (4). An adhesion strength between the thermosetting resin layer (3) and the thermoplastic resin layer (4) and an adhesion strength between the thermoplastic resin layers (4) and (5) are 50 gf/mm to 100 gf/mm, respectively. In the thermoplastic resin layer (4), a relative crystallinity calculated based on heat of fusion and heat of crystallization measured by differential scanning calorimetry is greater than or equal to 20% and less than or equal to 50%.