Stacked Motor Core Adhesion Layout for Lower Iron Loss
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Solution Overview
Problem
Conventional bonding and fixing methods for ultrathin electrical steel sheets in rotating electrical machines lead to increased iron loss due to elastic compressive stress from adhesive solidification, affecting magnetic characteristics.
Innovation Solution
A stacked core design with a plurality of electrical steel sheets and adhesion layers, where the area of the adhesion layer is varied depending on the direction of the main magnetic flux, with a smaller area in sections where the flux is generated in the easy-magnetization direction and a larger area in sections where the flux is generated in a direction intersecting with the easy-magnetization direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bonding and fixing method using adhesive is used to stack ultrathin electrical steel sheets, then the holding force for stacking and fixing is improved, but elastic compressive stress from adhesive solidification increases iron loss and deteriorates magnetic characteristics
Solution Approach 1:
The adhesion layer area is made non-uniform across different sections of the electrical steel sheet. Specifically, the adhesion layer area in the first section (where main magnetic flux is generated in the L-axis direction) is made smaller than in other sections, creating local quality differences that reduce compressive stress in critical magnetic flux paths while maintaining overall bonding strength
Solution Approach 2:
The electrical steel sheet is divided into multiple sections based on magnetic flux direction (L-axis and C-axis directions), and the adhesion layer area is differently configured in each section. This segmentation allows optimized adhesive distribution that reduces iron loss in critical areas while maintaining holding force overall
2Loss of energy
If adhesive area is reduced to suppress iron loss, then magnetic characteristics are improved, but holding force for stacking and fixing may be insufficient
Solution Approach 1:
Different sections of the electrical steel sheet have different adhesion layer areas tailored to their specific magnetic flux characteristics. Sections with L-axis flux have smaller adhesion areas to reduce iron loss, while other sections maintain larger adhesion areas to ensure sufficient holding force
Solution Approach 2:
The adhesion layer area is dynamically optimized based on the local magnetic flux direction and characteristics in each section, creating a non-uniform distribution that adapts to the magnetic field requirements of different regions
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 design effectively suppresses the increase in iron loss while maintaining a sufficient holding force for stacking and fixing, by optimizing the adhesion layer distribution based on the magnetic flux direction.
Implementation Method 1
a plurality of adhesion layers disposed between the electrical steel sheets adjacent to each other in a stacking direction
Implementation Method 2
an elastic compressive stress generated in the electrical steel sheet due to solidification shrinkage of the adhesive
Implementation Method 3
when an imaginary axis intersecting with a central axis of the annular body and extending in an easy-magnetization direction is defined as an L-axis, an imaginary axis intersecting with the central axis and intersecting with the L-axis is defined as a C-axis
Implementation Method 4
extending in an easy-magnetization direction
Implementation Method 5
an increase in iron loss due to high frequency excitation is an increase in eddy-current loss
Implementation Method 6
A main factor of an increase in iron loss due to high frequency excitation is an increase in eddy-current loss
Data Source
AI summary
An electrical steel sheet includes an annular body. At least one of a plurality of adhesion layers (41) is a first adhesion layer. In one of two electrical steel sheets sandwiching the first adhesion layer in a stacking direction, when an imaginary axis intersecting with a central axis of the annular body and extending in an easy-magnetization direction is defined as an L-axis, an imaginary axis intersecting with the central axis and intersecting with the L-axis is defined as a C-axis, and the electrical steel sheet is partitioned into a plurality of sections(S) in a circumferential direction of the annular body by the L-axis and the C-axis, at least one of the plurality of sections(S) is a first section. In the first section, an area of the first adhesion layer in a first portion (P1) of the electrical steel sheet where a main magnetic flux is generated in the L-axis direction is smaller than an area of the first adhesion layer in a second portion (P2) of the electrical steel sheet where the main magnetic flux is generated in the C-axis direction.