Patent ID: 8198777
Filing Date: 2012-06-12
Classification: H02K

Abstract:
1. An automotive alternator comprising: a rotor that creates a rotating magnetic field, the rotor including a rotating shaft, a pair of first and second pole cores, a plurality of permanent magnets, and a magnet holder, each of the first and second pole cores being fixed on the rotating shaft and including a plurality of claw poles extending in an axial direction of the rotating shaft, the claw poles of the first pole core being alternately arranged with the claw poles of the second pole core in a circumferential direction of the rotating shaft, each of the permanent magnets being interposed between a circumferentially-adjacent pair of the claw poles of the first and second pole cores to reduce leakage of magnetic flux therebetween, the magnet holder holding all the permanent magnets; and a stator that generates AC power in the rotating magnetic field created by the rotor, wherein the magnet holder is composed of first and second magnet holder pieces, each of the first and second magnet holder pieces is made of a nonmagnetic metal plate to have a one-piece structure, each of the first and second magnet holder pieces includes a plurality of receiving portions and a plurality of connecting portions, all the receiving portions of the first magnet holder piece have the same orientation and each receive therein a corresponding one of the permanent magnets, each of the connecting portions of the first magnet holder piece extends in the circumferential direction of the rotating shaft to connect a circumferentially-adjacent pair of the receiving portions of the first magnet holder piece, all the receiving portions of the second magnet holder piece have the same orientation and each receive therein a corresponding one of the permanent magnets, and each of the connecting portions of the second magnet holder piece extends in the circumferential direction of the rotating shaft to connect a circumferentially-adjacent pair of the receiving portions of the second magnet holder piece.