Insulated Wire Foamed Layer High Melting Point Outer Shell
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Solution Overview
Problem
Existing insulated wires for inverter-related equipment face challenges in achieving high partial discharge inception voltage and abrasion resistance while maintaining a low relative dielectric constant, which is essential for miniaturization and performance in electrical equipment.
Innovation Solution
The development of an insulated wire with a foamed thermosetting resin insulating layer and an outer thermoplastic resin layer having a melting point of 240°C or higher, or a glass transition temperature of 240°C or higher, along with a specific thickness ratio between the foamed and outer insulating layers, to enhance both partial discharge resistance and abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the insulating layer is increased to reduce partial discharge deterioration, then the partial discharge inception voltage is improved, but the insulated wire becomes thicker and the space factor decreases
Solution Approach 1:
The patent applies composite materials by combining a thermosetting resin base material with thermoplastic resin particles dispersed within it. This composite structure provides enhanced partial discharge resistance through the thermoplastic particles while maintaining a thin overall insulating layer thickness, thus resolving the contradiction between reliability and volume.
Solution Approach 2:
The insulating layer incorporates a foamed structure with controlled cell sizes (1 μm to 5 μm), creating a porous material that reduces the relative dielectric constant and improves partial discharge inception voltage without significantly increasing the overall thickness of the insulating layer.
2Reliability
If a resin with low relative dielectric constant is used to reduce partial discharge, then the partial discharge inception voltage is improved, but other required properties (heat resistance, solvent resistance, flexibility) cannot be satisfied
Solution Approach 1:
The patent creates a composite material system where the thermosetting resin provides heat resistance, solvent resistance, and flexibility, while the dispersed thermoplastic resin particles contribute to lowering the relative dielectric constant and improving partial discharge resistance. This composite approach allows simultaneous satisfaction of multiple conflicting requirements.
Solution Approach 2:
The patent applies local quality by dispersing thermoplastic resin particles specifically within the thermosetting resin matrix, creating regions with different properties. The thermoplastic particles locally reduce the dielectric constant where needed for partial discharge resistance, while the thermosetting resin maintains the required mechanical and thermal properties throughout the insulating layer.
3Object-affected harmful factors
If particles are incorporated into the insulating film to reduce corona discharge deterioration, then the resistance to corona discharge is improved, but the partial discharge inception voltage decreases and flexibility of the coated film decreases
Solution Approach 1:
The patent uses a foamed structure with controlled cell sizes instead of incorporating dense particles. The foam cells create a porous structure that reduces the relative dielectric constant and improves partial discharge inception voltage without the negative effects of particle incorporation on flexibility and discharge characteristics.
Solution Approach 2:
The patent changes the physical state and distribution of the resin material by creating a foamed structure with specific cell size parameters (1 μm to 5 μm). This parameter change in the insulating layer's physical structure achieves corona discharge resistance and improved partial discharge inception voltage without sacrificing film flexibility.
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 an insulated wire with improved partial discharge inception voltage and abrasion resistance, effectively addressing the limitations of existing technologies while maintaining a low relative dielectric constant, thus supporting the miniaturization and performance demands of electrical equipment.
Implementation Method 1
a foamed insulating layer containing a thermosetting resin having cells (air bubbles)
Implementation Method 2
by the insulating films containing particles. However, the insulated wires having insulating films containing these particles have problems that the effect is insufficient so that a partial discharge inception voltage is decreased
Implementation Method 3
an outer insulating layer containing a thermoplastic resin having a melting point of 240°C or higher in the case where the thermoplastic resin is a crystalline resin or a thermoplastic resin having a glass transition temperature of 240°C or higher
Implementation Method 4
the thermoplastic resin has a storage elastic modulus of 1 GPa or more at 25°C
Data Source
Figure 1(a)~2(b)
Figure 3(a)~3(b)
AI summary
An insulated wire having a conductor, a foamed insulating layer containing a thermosetting resin having cells, coated directly or indirectly onto the outer periphery of the conductor and an outer insulating layer containing a thermoplastic resin having a melting point of 240°C or higher when the thermoplastic resin is a crystalline resin or a thermoplastic resin having a glass transition temperature of 240°C or higher when the thermoplastic resin is a non-crystalline resin; electrical equipment using the insulated wire; and a method of producing the insulated wire, containing a step of forming a foamed insulating layer by applying a varnish for forming the foamed insulating layer on the outer periphery of a conductor, by generating foams during baking and a step of forming an outer insulating layer by extrusion-molding a thermoplastic resin composition for forming the outer insulating layer on the outer periphery of the foamed insulating layer.