Laminated Motor Core Structure With Selective Tooth Adhesion

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Solution Overview

Problem

The magnetic properties of existing laminated cores are not optimized, leading to increased iron loss and potential strain due to adhesive application and fastening methods, which can affect the magnetic circuit and overall performance of electric motors.

Innovation Solution

A laminated core design featuring alternating tooth parts with and without adhesion, where the adhesion is applied only to some tooth parts and fastening is strategically placed in the core back part corresponding to specific tooth parts, minimizing strain and stress, thereby improving magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive is applied to all tooth parts for lamination, then lamination strength is improved, but strain occurs in all tooth parts causing increased iron loss

Engineering Contradiction:
Improvelamination strengthVSAvoidiron loss
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The tooth parts are segmented into two groups: first tooth parts with adhesion parts where adhesive is applied, and second tooth parts without adhesion parts where no adhesive is applied. This segmentation allows selective adhesion to reduce overall strain while maintaining necessary lamination strength in critical areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different adhesion qualities are applied to different tooth parts. The first tooth parts have full adhesion for strong bonding, while the second tooth parts have no adhesion to avoid strain. This local differentiation optimizes the balance between lamination strength and strain reduction.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If fastening part is provided in the core back part corresponding to tooth parts, then lamination stability is improved, but magnetic flux path may be obstructed

Engineering Contradiction:
Improvelamination stabilityVSAvoidiron loss
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The fastening part, which could potentially obstruct magnetic flux, is strategically positioned in the core back part corresponding to tooth parts. This converts a potential harmful effect into a beneficial one by utilizing the natural magnetic flux distribution pattern where flux branches at tooth parts, minimizing obstruction while maintaining lamination stability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If adhesive is applied to tooth parts, then adhesion between layers is improved, but compressive stress and strain occur during curing

Engineering Contradiction:
Improveadhesion between layersVSAvoidcompressive stress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The tooth parts are divided into first tooth parts with adhesion parts where adhesive is applied for strong layer bonding, and second tooth parts without adhesion parts where no adhesive is applied. This segmentation reduces the total area subject to compressive stress during curing while maintaining necessary adhesion in critical regions.

Inventive Principle:
Principle #1Segmentation

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 configuration reduces iron loss and enhances magnetic properties by balancing compressive stress and winding-induced stress, resulting in improved performance of electric motors.

Implementation Method 1

an adhesive shrinks during curing. Therefore, when the adhesive is provided on the electrical steel sheet, a compressive stress is applied to the electrical steel sheet as the adhesive cures

Methodology Applied
Scientific EffectAdhesive shrinkage: Adhesive

Implementation Method 2

a region of the core back part not corresponding to any of the tooth parts (a region between adjacent tooth parts) is a path of a magnetic flux

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentEP3902113B1Laminated core and electric motor
Publication Date: 2024.08.21 NIPPON STEEL CORPORATION
  • EP3902113B1 patent drawingFigure 1
  • EP3902113B1 patent drawingFigure 2
  • EP3902113B1 patent drawingFigure 3

AI summary

A laminated core includes a plurality of electrical steel sheets stacked in a thickness direction, the electrical steel sheet includes an annular core back part and a plurality of tooth parts that protrude from the core back part in a radial direction and are disposed at intervals in a circumferential direction of the core back part, a fastening part is provided in a portion of the core back part corresponding to the tooth part, and an adhesion part is provided in the tooth part.