Patent ID: 7781923

Claim:
An AC generator for a vehicle comprising: a frame accommodating a rotor and a stator; and an end cover made of mold resin, which is fixed to the frame, accommodating electrical components including a rectifier device capable of rectifying an output voltage of a stator coil of the stator fixed to an outer end surface of the frame, the rectifier device comprising a flat plate part extending approximately in a radius direction, a rib part projecting from the plate part toward the end cover, and a cooling fin part facing the end cover, wherein the end cover has a first part which is close to the rib part of the rectifier device and a second part which is close to the flat plate part and away from the rib part, and the first part is stronger in anti-thermal stress than the second part, the first part which is close to the rib part of the rectifier device is thinner in thickness than the second part, and the inner surface of the first part in the end cover, which faces the rib part of the cooling fin in the rectifier device, is curved toward the outside of the end cover so that the first part of the end cover is a concave part which is thinner in thickness than the second part.