摘要 |
One end of a metallic wire having a rectangular cross-section is widened by upsetting the end of the wire in its axial direction. At the same time, a swollen portion is formed at a position where the widened end portion is to be bent from a straight portion of the wire. Then, the widened end portion is bent at the bending position having the swollen portion. Thus, a metallic wire segment having the widened end portion bent at the bending position is manufactured without wasting any part of wire material, while avoiding formation of cracks on the outer surface of the bending position. Plural wire segments thus manufactured are combined to form a rotor winding of a rotational electric machine, forming a commutator surface by the widened end portions at the same time.
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