Patent ID: 7091637

Claim:
An ac generator for a vehicle, comprising: a housing including a drive frame, a rear frame and a rear cover; a rotor, supported by said housing, for providing a magnetic field; a cooling fan fixed to said rotor for taking cooling air from outside of the rear cover; a stator, supported by said housing and disposed around said rotor, said stator having a stator core in which a plurality of phase-windings is mounted to generate multi-phase electromotive forces when the magnetic field is supplied; and a multi-phase full-wave rectifying unit disposed in the rear cover and formed by a bridge circuit which includes a plurality of input terminals respectively connected to the plurality of phase-windings, a positive output terminal, a negative output terminal, positive electrode side rectifying elements having one ends respectively connected to the input terminals and the other ends connected to the positive output terminal, negative electrode side rectifying elements having one ends respectively connected to the input terminals and the other ends connected to the negative output terminal, a semicircular positive electrode side heat sink to which the positive electrode side rectifying elements are fixed and a semicircular negative electrode side heat sink to which the negative electrode side rectifying elements are fixed, said positive electrode side heat sink and said negative electrode side heat sink being respectively disposed in two planes that are perpendicular to a rotation axis of said rotor, wherein said negative electrode side heat sink comprises a pair of separate semicircular plates that have a larger outside diameter than the positive electrode side heat sink to utilize cooling air taken by said cooling fan from outside of the rear cover, and wherein one of the negative electrode side rectifying elements is constituted of parallelly connected two elements that are respectively fixed to the semicircular plates to equally divide current flowing through one of the input terminals.