Patent ID: 7755249

Claim:
An alternator, comprising: a stator; and a rotor, disposed in a center hole of the stator, which is rotated on its own axis to generate electric power in the stator, the rotor comprising: a pole core having a plurality of claw portions disposed along a circumferential direction of the rotor; a field coil disposed on an inner side of the claw portions in a radial direction of the rotor; a plurality of holder units each of which is disposed between two claw portions adjacent to each other such that the holder units and the claw portions are alternately arranged along the circumferential direction; and a plurality of magnets, respectively, disposed in the holder units, each holder unit comprising: a magnet accommodating holder, formed substantially in a box shape so as to have a bottom wall, four side walls extending from the bottom wall and an opening on respective six faces, which accommodates the corresponding magnet; and a magnet covering holder, formed substantially in a box shape so as to have a bottom wall, four side walls extending from the bottom wall and an opening on respective six faces, which accommodates the magnet accommodating holder so as to cover the magnet exposed to the opening of the magnet accommodating holder and is disposed between the corresponding claw portions such that the opening of the magnet covering holder faces toward a side in the radial direction, each of the side walls of the magnet accommodating holder having a first convexity which is in elastic contact with the magnet, the bottom wall of at least one of the magnet accommodating holder and the magnet covering holder having a second convexity which is in elastic contact with the magnet.