Patent ID: 7716810

Claim:
A manufacturing method of a commutator, comprising: arranging a plurality of segments in an outer circumference of a cylindrical insulating body; preparing a plurality of first short-circuit pieces and a plurality of second short-circuit pieces, each of the first short-circuit pieces having a first radially outer end, a first radially inner end arranged at a position which is circumferentially deviated from and radially inside of the first radially outer end, and a first coupling portion coupling the first radially outer end to the first radially inner end, and each of the second short-circuit pieces having a second radially outer end, a second radially inner end arranged at a position which is circumferentially deviated from and radially inside of the second radially outer end, and a second coupling portion coupling the second radially outer end to the second radially inner end; forming a first through hole and a second through hole respectively in the first radially outer end and the second radially outer end which are in a separated state from each other; forming a combined through hole by overlapping each first radially outer end with the corresponding second radially outer end so as to communicate the first through hole with the second through hole, the combined through hole having a first opening and a second opening in an opposite side to the first opening; forming a tabular insulating portion covering the first coupling portion and the second coupling portion; forming a restriction recess in one of the insulating body or the tabular insulating portion, and forming a restriction projection in the other; engaging the restriction projection with the restriction recess; closing the first opening by a layout surface corresponding to an end surface in an axial direction of the segment; and irradiating a laser beam onto at least a part of the circumference of the second opening, the laser beam passing through the combined through hole so as to be irradiated onto the layout surface, whereby the first radially outer end, the second radially outer end and the segment are welded.