Core Sheet Insulation Removal for Directional Magnetization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing core sheets in rotating electric machines fail to optimize magnetic properties in both the tooth portions and core back portions, leading to difficulties in magnetization and reduced performance due to mismatched easy directions of magnetization.
Innovation Solution
A method involving grain-oriented magnetic steel sheets with insulation coatings, where the core back portion is partially or completely stripped of insulation coatings to align the easy direction of magnetization with the circumferential direction, while maintaining insulation coatings on tooth portions to keep magnetization ease in radial directions high.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation coating is applied on the entire surface including core back portion, then insulation performance is improved, but magnetic properties in core back portion deteriorate due to tension-induced misalignment of easy magnetization direction
Solution Approach 1:
The insulation coating is segmented into two regions: tooth portions retain insulation coating for electrical insulation, while core back portion has insulation coating removed to preserve magnetic properties. This spatial segmentation resolves the contradiction by applying insulation only where electrically necessary.
Solution Approach 2:
Different surface treatments are applied to different regions: tooth portions maintain insulation coating for electrical isolation, while core back portion has insulation removed to allow proper magnetization alignment. This local differentiation optimizes both insulation performance and magnetic properties in their respective regions.
2Ease of manufacture
If insulation coating is removed from core back portion, then magnetic properties are improved, but insulation performance deteriorates
Solution Approach 1:
The core sheet is divided into tooth portions and core back portion, with insulation coating selectively retained on tooth portions and removed from core back portion. This segmentation maintains insulation performance in critical areas while improving magnetic properties where insulation would be detrimental.
Solution Approach 2:
The surface treatment varies by location: insulation coating is removed from core back portion to enable proper magnetization, while tooth portions retain insulation for electrical isolation. This local quality differentiation resolves the contradiction between magnetic performance and insulation requirements.
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 enhances magnetic properties in both the core back and tooth portions, improving the overall performance and reducing magnetic reluctance, thus enabling smaller and more efficient rotating electric machines.
Implementation Method 1
an insulation coating formed on its surface to apply tension in the easy direction of magnetization
Implementation Method 2
the grain-oriented magnetic steel sheet having an easy direction of magnetization in one in-plane direction
Data Source
AI summary
Disclosed is a method of manufacturing a core sheet. The core sheet has an annular core back portion and a plurality of tooth portions extending from the core back portion toward a radial center thereof. The method includes a blanking step, a rolling step and a removing step. In the removing step, an insulation coating, which is on a region of a grain-oriented magnetic steel sheet for forming a band-shaped core back portion, on a band-shaped core back portion of a sheet piece or on the core back portion of the core sheet, is at least partially removed.