Insulated Wire Convex Film Thickness Prevents Delamination
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Solution Overview
Problem
Conventional insulated wires face challenges in balancing improved partial discharge inception voltage with adhesion properties, particularly during the manufacturing process where film delamination occurs due to high-speed wire interactions, leading to low abrasion resistance and adhesion issues.
Innovation Solution
The development of an insulated wire with a laminated resin-coated structure, featuring a thermosetting resin layer with convex portions and an extrusion-coated thermoplastic resin layer, where the a/b ratio of minimum to maximum film thickness is between 0.60 and 0.90, enhancing adhesion and preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating layer is thickened to increase partial discharge inception voltage, then the adhesion property between conductor and enamel-baked layer deteriorates, causing film delamination during high-speed wire interactions
Solution Approach 1:
The patent applies local quality by creating convex portions (protrusions) at specific locations on the enamel-baked layer surface. These localized thickened regions provide enhanced adhesion anchors without requiring uniform thickness increase across the entire insulating layer, thus maintaining high partial discharge inception voltage while preventing film delamination during high-speed wire interactions.
Solution Approach 2:
The patent employs composite materials by combining the enamel-baked layer with an extrusion-coated resin layer. This layered composite structure allows the enamel-baked layer to provide the base insulating properties and the extrusion-coated layer to provide enhanced adhesion and surge voltage resistance, resolving the contradiction between thickness requirements and adhesion properties.
2Object-affected harmful factors
If a uniform thick insulating layer is applied to resist inverter surge, then the working suitability deteriorates due to film delamination during coil manufacturing
Solution Approach 1:
The convex portions are strategically positioned on the enamel-baked layer to provide localized reinforcement exactly where wire interactions occur during coil manufacturing. This localized approach improves working suitability by preventing delamination at critical points without requiring excessive overall thickness that would compromise ease of operation.
Solution Approach 2:
The convex portions are formed on the enamel-baked layer surface before the extrusion-coating process. This preliminary action ensures that the adhesion-enhancing features are already in place to prevent delamination during subsequent high-speed wire interactions in coil manufacturing, improving working suitability before the harmful inverter surge even occurs.
3Reliability
If the insulating layer thickness is increased to prevent partial discharge deterioration, then the abrasion resistance decreases due to film delamination
Solution Approach 1:
The convex portions provide localized adhesion reinforcement at the interface between the enamel-baked layer and extrusion-coated resin layer. This localized reinforcement prevents film delamination during abrasive wire interactions, thereby improving abrasion resistance without requiring a uniform increase in insulating layer thickness that would compromise partial discharge resistance.
Solution Approach 2:
The composite structure of enamel-baked layer plus extrusion-coated resin layer creates a synergistic effect where the combined layers provide both the thickness needed for partial discharge resistance and the interfacial adhesion provided by the convex portions for abrasion resistance, resolving the contradiction between these two reliability aspects.
Data Source
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AI summary
An insulated wire comprising a laminated resin-coated insulated wire containing: a thermosetting resin layer (A) directly or via an insulating layer (D) on a conductor having a rectangular cross-section; and at least a thermoplastic resin layer (B) on the outer periphery of the thermosetting resin layer (A), in which the cross-sectional shape of the thermosetting resin layer (A) composed of two pairs of two sides facing each other, and has at least four convex portions each of which has a film thickness in maximum, at least one convex portion of the at least four convex portions is on each of the four sides, or at least two convex portions of the at least four convex portions are at least on each of the two sides facing each other, and in the each side having the convex portion, provided that a minimum film thickness is designated as "a" µm, and an average of maximum film thicknesses of the convex portions is designated as "b" µm, the a/b ratio is 0.60 or more and 0.90 or less; a coil, and electric/electronic equipments as well as a method of preventing a film delamination of an insulated wire.