Patent ID: 7183677

Claim:
An alternator for use in an automotive vehicle, the alternator comprising: a housing including a front frame and a rear frame; a cylindrical stator including an armature coil, the cylindrical stator being contained in the housing; a rotor rotatably disposed inside the cylindrical stator and supported in the housing; a rectifier mounted on and contained in the housing; a separating wall separating the rectifier from the rotor in the axial direction; and a cooling fan for sucking cooling air through air inlets formed on the separating wall after cooling the rectifier, the cooling fan being connected to the rotor, wherein: the rectifier includes an outer heatsink plate on which rectifier elements are mounted and an inner heatsink plate on which other rectifier elements are mounted, the outer heatsink plate being disposed to face the separating wall forming an air passage therebetween, the inner heatsink plate being disposed to face the rear frame; the outer heatsink plate includes cooling fins extending toward the rear frame in the axial direction and forming radial air passages between the cooling fins; and the rear frame includes radial openings that are open in a radial direction of the rotor, so that the cooling air is introduced from the radial openings upon rotation of the cooling fan and flows through the radial air passages between the cooling fins and through the air passage between the outer heatsink plate and the separating wall.