Patent ID: 7057315

Claim:
An automotive alternator, comprising: a stator having an armature winding; a rotor having a field winding wound on a pole core and a rotor shaft to which the pole core is fixedly connected, the rotor being rotatably supported inside the stator; a cooling fan positioned at an axial end of the pole core; and a fan base for rectifying airflows generated by the cooling fan, the fan base being disposed between the axial end of the pole core and the cooling fan, wherein: the rotor shaft includes a non-circular flange, and either the cooling fan or the fan base is coupled to the non-circular flange so that the cooling fan is correctly positioned relative to the rotor shaft both in a radial direction and in a rotational direction of the cooling fair; the cooling fan includes a plurality of fan blades extending in the axial direction of the rotor and a supporting plate supporting the plurality of fan blades; a first opening to which the non-circular flange of the rotor shaft is inserted is formed at a center portion of the supporting plate; and first engaging edges engaging with the non-circular flange are formed at a fringe of the first opening.