US Patent 7854055 Method for producing a commutator

A commutator includes a conductive part that has a cylindrical body and a plurality of coil latching portions at intervals circumferentially on one axial end; and an insulating part formed inside the conductive part. The conductive part includes segments that are insulated for each latching portion by cutting axially the conductive part, and latching claws that are provided in a projecting state on an inner peripheral surface of the segments and embedded in the insulating part, wherein the latching claws include axial latching claws that are long in an axial direction and project inward, and circumferential latching claws that project circumferentially.