Patent ID: 6888275

Claim:
An alternator for use in an automotive vehicle, the alternator comprising: a housing formed in a substantially cylindrical shape having an axial end wall; a stator fixedly disposed in the housing; a rotor rotatably supported inside the stator, the rotor including a cooling fan fixed to its axial end surface, wherein: a plurality of spokes are formed on the axial end wall of the housing; air inlet ports facing the cooling fan are formed between neighboring spokes, so that cooling air is introduced into the housing through the inlet ports according to rotation of the cooling fan fixed to the rotor; a plurality of ribs are formed between the neighboring spokes, the spokes being larger in both the height and the width than the ribs and having a larger mechanical strength than the ribs; and the spokes are tilted in a direction opposite to a rotational direction of the rotor with respect to a radial line extending from a rotational center of the rotor.