US Patent 9502939 Method for manufacturing an armature core

A method for manufacturing a stator configured to ensure insulation properties between a conductor and an armature core while preventing a manufacturing cost from increasing and preventing a space factor from lowering. In an edge-removing step, a plurality of independent edge-removing punches, which correspond to one slot S or two or more slots S, press and chamfer a corner portion of an axial opening edge of the slot in an axial end core sheet of the armature core.