Insulated Wire Pre-Heating for Anti-Corona Adhesion

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Solution Overview

Problem

Conventional methods for producing insulated electric wires with anti-corona characteristics face challenges in achieving high bonding strength and cost-effectiveness, particularly in maintaining bonding strength between coating layers and preventing corona discharge, especially when manufacturing conditions change.

Innovation Solution

A method involving pre-heating the primary coating layer of the insulated electric wire to specific temperatures below the glass transition point of the enamel-baking layer or adhesive layer, followed by extrusion of a secondary coating layer using polyphenylene sulfide resin, ensuring strong adhesion and preventing corona discharge, while maintaining cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the enamel-baking layer is increased to prevent corona discharge, then anti-corona discharge resistance is improved, but production cost increases due to higher material consumption

Engineering Contradiction:

Improveanti-corona discharge resistanceVSAvoidenamel varnish consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies composite materials by combining two different coating layers: an enamel-baking layer (B1) and a resin extrusion layer (C). The enamel-baking layer provides base insulation, while the resin extrusion layer (using materials like polyphenylene sulfide) provides enhanced anti-corona discharge resistance. This composite structure allows achieving the required corona discharge prevention performance without excessively thickening the expensive enamel-baking layer, thus resolving the contradiction between reliability and material consumption.

Inventive Principle:

Principle #40Composite materials

2Strength

If the bonding strength between primary coating layer and secondary coating layer is improved, then product quality is enhanced, but manufacturing complexity increases due to additional process steps

Engineering Contradiction:

Improvebonding strength between coating layersVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent employs preliminary action by implementing a pre-heating step before the resin extrusion process. The primary coating layer is pre-heated to a specific temperature range (50-150°C) before the resin is extruded onto it. This pre-heating prepares the surface of the primary coating layer to enhance adhesion, ensuring strong bonding between the layers without requiring complex chemical treatments or additional manufacturing steps, thus improving strength while keeping process complexity manageable.

Inventive Principle:

Principle #10Preliminary action

3Quantity of substance

If a less expensive extrusion resin is used to reduce production cost, then cost-effectiveness is improved, but bonding strength between coating layers deteriorates

Engineering Contradiction:

Improveproduction costVSAvoidbonding strength between coating layers

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the temperature parameter during the resin extrusion process. The resin is extruded at a controlled temperature, and the primary coating layer is pre-heated to a specific temperature range (50-150°C). These temperature parameter adjustments ensure that even less expensive extrusion resins can achieve adequate bonding strength with the primary coating layer, thus improving cost-effectiveness while maintaining acceptable bonding strength.

Inventive Principle:

Principle #35Parameter changes

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

This approach stabilizes the production of high-quality insulated electric wires with improved anti-corona discharge resistance and bonding strength, ensuring consistent quality and cost savings even when manufacturing conditions vary.

Implementation Method 1

pre-heating the primary coating layer of the insulated electric wire to specific temperatures below the glass transition point of the enamel-baking layer or adhesive layer

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

ensuring strong adhesion and preventing corona discharge

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 3

the insulated electric wire used in the motors tends to be exposed to environments where a corona discharge may occur (a discharge caused by a non-uniform electrical field occurring around a sharp electrode; also known as a local breakage discharge)

Methodology Applied

Scientific EffectCorona discharge: Corona Discharge

Data Source

PatentUS8790747B2Method and apparatus for producing insulated wire

Publication Date: 2014.07.29 ESSEX FURUKAWA MAGNET WIRE LLC

AI summary

Disclosed is a method of producing an insulated electric wire, in which a primary coating layer including at least an enamel-baking layer is formed on a metallic conductor to form a primary coated electric wire, and a secondary coating layer is extrusion-formed on the primary coating layer of the primary coated electric wire. The method includes an electric wire pre-heating process where a surface of the primary coating layer is pre-heated using an electric wire pre-heating unit, and a resin extrusion process where a secondary coating layer is extrusion-formed on the pre-heated primary coating layer using a resin extrusion unit. Further disclosed is an apparatus for producing an insulated electric wire.