Patent ID: 11881341
Assignee: NIPPON STEEL CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of manufacturing a core sheet, the core sheet having an annular core back portion and a plurality of tooth portions extending from the annular core back portion toward a radial center thereof,
the method comprising steps of:
blanking out a sheet piece from a grain-oriented magnetic steel sheet, the grain-oriented magnetic steel sheet having an easy direction of magnetization in one in-plane direction and an insulation coating formed on its surface to apply tension in the easy direction of magnetization, the sheet piece having a band-shaped core back portion extending in a perpendicular direction to the easy direction of magnetization and a plurality of parallel tooth portions extending, from the band-shaped core back portion, parallel to the easy direction of magnetization;
rolling the sheet piece, with the parallel tooth portions being on an inner side, into an annular shape, thereby obtaining the core sheet having the core back portion and the tooth portions; and
partially removing the insulation coating on the band-shaped core back portion of the sheet piece or the insulation coating on the core back portion of the core sheet.