Patent ID: 7741739

Claim:
An automotive alternator comprising: a case; an axially extending shaft that is rotatably supported by said case; a rotor that is accommodated inside said case and that has: a pole core that is fixed to said shaft; a field winding that is mounted to said pole core; and at least one centrifugal fan that is fixed to an axial end of said pole core; a stator that is fixed to said case so as to surround said rotor; a voltage regulator that adjusts magnitude of an alternating voltage that is generated in said stator; a voltage regulator heatsink that has a base portion and a plurality of fins that are disposed upright on a first surface of the base portion of said voltage regulator so as to be arrayed circumferentially at a predetermined pitch; and a connector that is disposed on an outer circumferential side of said voltage regulator and to which an external plug can be mounted, a plurality of cooling air intake apertures being formed on a side of said case that faces said centrifugal fan, and said voltage regulator being disposed such that said plurality of fins faces said case, wherein a cooling airflow introducing guide portion is disposed on a portion of said connector, faces radially-outer side surfaces of said fins of said voltage regulator heatsink, and forms a clearance between said cooling airflow introducing guide portion and said voltage regulator heatsink, wherein said clearance between said cooling airflow introducing guide portion and said voltage regulator heatsink is greater than that between said fins, and an outermost radial position of said voltage regulator heatsink is positioned radially outside said cooling air intake apertures, whereby a portion of the cooling airflow flows radially inward through between said fins, and a remaining portion of the cooling airflow flows radially outward between said fins, and then flows circumferentially between said fins and said cooling airflow introducing guide portion.