Patent ID: 7610973

Claim:
An automotive electric motor-generator apparatus comprising: a battery; an engine; a rotary electric machine linked to said engine by means of a pulley and a belt, said rotary electric machine being driven by electric power from said battery to start said engine during starting of said engine, and being driven by said engine to generate alternating-current power after starting said engine; and an inverter unit for converting direct-current power from said battery into alternating-current power and supplying said alternating-current power to said rotary electric machine during said starting of said engine, and converting alternating-current power generated in said rotary electric machine into direct-current power and charging said battery after starting said engine, wherein said rotary electric machine comprises: a rotor including a field winding and a supported shaft, and being rotatably disposed inside a case formed by a front bracket and a rear bracket; a fan fixed to an axial end surface of said rotor; and an armature disposed between said front bracket and said rear bracket so as to cover said rotor; wherein said inverter unit comprises: a resin case made of electrically-insulating resin; a heat sink formed integrally with said resin case, said heat sink having a C shape and including fins extending radially disposed upright at a predetermined angular pitch in a circumferential direction on an inner wall surface of said heat sink; and a circuit board disposed on said heat sink in an electrically-insulated state and housed inside said resin case; and wherein said inverter unit is disposed outside the case so as to surround a bearing box of said rear bracket and directly mounted to an axial end surface of said rear bracket which is perpendicular to a center of said shaft, whereby said inverter unit is cooled by a cooling airflow formed by said fan and flowed along said fins.