Method of manufacturing laminated core

Abstract

In a method of manufacturing a laminated magnetic core by laser welding successive core sheets, the core sheets are stacked one on another to form a stacked body of core sheets, and while the stacked body of core sheets is moved in a stepwise manner in a thickness direction perpendicular to a surface of the core sheet with respect to at least one optical fiber exit unit from which a laser beam is projected onto an outer surface of the stacked body of core sheets, the laser beam is intermittently projected onto the stacked body of core sheets such that at least successive three core sheets are welded together, and then the stacked body of core sheets is moved in the thickness direction over a distance substantially equal to at least a twice of the thickness of core sheets. When a plurality of optical fiber exit units are provided such that they are separated in a surface direction perpendicular to the thickness direction, a plurality of laser beams are projected simultaneously or alernately each time the stacked body of core sheets is moved in the thickness direction over a distance substantially equal to at least the thickness of core sheets. In this manner according to the invention, it is possible to obtain welded areas which are separated in the thickness direction and/or in the surface direction.