Laminated Iron Core Steel Sheets Surface Roughness Control
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Solution Overview
Problem
Conventional methods for manufacturing laminated iron cores face issues such as insufficient adhesion between steel sheets, shape deviations, and reduced productivity due to increased thickness of adhesion layers, leading to decreased magnetic properties and increased energy loss.
Innovation Solution
The use of steel sheets with a surface roughness of 0.40 μm or less and sheet thickness deviation of 3 μm or less per 500 mm, combined with a cold rolling and surface treatment process to reduce air gaps between overlapped sheets, allowing for improved punching accuracy and high space factor without the need for adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sheet thickness of electrical steel sheets is thinned down to reduce eddy current loss, then energy loss is reduced, but the number of laminated sheets increases leading to reduced productivity and increased warping
Solution Approach 1:
The invention changes the surface roughness parameter of the steel sheets to Ra 0.40 μm or less, which enables adequate adhesion without requiring excessive sheet thickness or numerous laminations, thus maintaining productivity while achieving energy efficiency
Solution Approach 2:
The invention creates a composite structure by adhering multiple steel sheets together through controlled surface roughness, forming a laminated iron core that combines the benefits of thin sheets (low eddy current loss) with adequate adhesion (maintained productivity)
2Loss of energy
If sheet thickness of electrical steel sheets is thinned down, then eddy current loss is reduced, but stiffness decreases causing warping and bending in punched out bodies
Solution Approach 1:
The invention changes the surface roughness parameter to Ra 0.40 μm or less, which provides adequate friction and adhesion between thin steel sheets, preventing warping and bending while maintaining the thin sheet configuration for low eddy current loss
3Strength
If adhesion layer thickness is increased to improve adhesion between steel sheets, then adhesion strength is improved, but space factor decreases and manufacturing complexity increases
Solution Approach 1:
The invention changes the surface roughness parameter to Ra 0.40 μm or less, which achieves adequate adhesion strength through optimized surface characteristics rather than increased layer thickness, thereby maintaining space factor and reducing manufacturing complexity
Solution Approach 2:
The invention extracts the adhesion function from a separate thick adhesion layer and integrates it into the steel sheet surface structure itself through controlled roughness, eliminating the need for complex additional adhesion layers
Data Source
AI summary
A material for laminated iron cores is used as plural steel sheets to be overlapped with one another and punched when a laminated iron core is manufactured. A surface roughness of the steel sheets forming the material for laminated iron cores is at an arithmetic mean roughness Ra of 0.40 [μm] or less, and a sheet thickness deviation in a sheet width direction of at least a portion used as the laminated iron core is 3 [μm] or less per 500 [mm], the portion being of the steel sheets forming the material for laminated iron cores.