Shape Memory Winding Material for Electrical Coil Cooling

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Solution Overview

Problem

Existing methods for producing electrical windings with embedded cooling liquids face issues where insulation layers become loose, causing gaps between turns to clog and impairing long-term cooling efficiency.

Innovation Solution

Using a strip or strand-shaped winding material made of plastic with embossed shape memory that shortens when heated, ensuring a permanent gap for coolant passage by shrinking around the conductor after wrapping and heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If paper layers are wrapped around the conductor as insulation, then the conductor is adequately insulated, but the paper layers become loose and bunch up, causing gaps between turns to clog

Engineering Contradiction:
Improvecooling efficiencyVSAvoidinsulation layer stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the physical parameters of the winding material by using a plastic with shape memory that undergoes thermal contraction. The material is stretched during winding to achieve tight wrapping, then heated during operation to contract and lock the gaps open, preventing paper layers from becoming loose and bunching up.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by stretching the winding material before winding it around the conductor. This pre-stretching ensures that when the material is later heated, it contracts to the correct tension, permanently maintaining the gap structure before any loosening can occur.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the winding material is stretched during winding, then the wrapping strength is sufficient, but the material needs to be heated to maintain the gap structure

Engineering Contradiction:
Improvewrapping strengthVSAvoidprocessing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent utilizes phase transition by employing a plastic material that changes its physical state through thermal heating. The material transitions from a stretched, flexible state during winding to a contracted, rigid state when heated, automatically maintaining the gap structure without additional mechanical fastening.

Inventive Principle:
Principle #36Phase transitions

3Ease of operation

If conventional winding material is used, then the conductor has sufficient flexibility for processing, but the gaps between turns are not permanently maintained

Engineering Contradiction:
Improveconductor flexibilityVSAvoidgap maintenance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by using a winding material whose properties change over time and conditions. The material is flexible and stretchable during the winding process for ease of handling, then becomes rigid and contractile when heated during operation, dynamically adapting to maintain gap structure.

Inventive Principle:
Principle #15Dynamics

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

Maintains effective cooling by securely maintaining the gap between winding turns, ensuring consistent cooling performance over time.

Implementation Method 1

a strip or strand-shaped winding material made of a plastic with an embossed shape memory, which has a length produced by stretching that is greater than its original length and becomes shorter when heat is applied

Methodology Applied
Scientific EffectShape memory: Shape Memory Polymer

Implementation Method 2

the finished winding is heated to a temperature at which the winding material becomes shorter in the winding direction

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP2387047B1Electrical conductor and method for producing an electrical coil
Publication Date: 2012.06.06 ESSEX EURO
  • EP2387047B1 patent drawingFigure 1~2

AI summary

A method for manufacturing an electrical winding for an electrical device is described, in which the winding is embedded in a cooling liquid. First, a conductor is produced in which a plurality of insulated electrical conductors with a rectangular cross-section are arranged in at least one stack, with their flat sides touching each other. To create a common insulation, a winding material consisting of insulating material is wound around the stack, and then the conductor is formed into a single winding. For the winding, a ribbon or strand-shaped winding material made of a plastic with imprinted shape memory is used, which has a greater length than its original length due to stretching. The finished winding is heated to a temperature at which the winding material shortens in the winding direction.