Patent ID: 6690099
Filing Date: 2004-02-10
Classification: H02K

Abstract:
An automotive alternator comprising:a shaft rotatably supported by a case; a rotor fixed to said shaft, said rotor being provided with: a field winding for generating a magnetic flux on passage of an electric current therethrough; and a plurality of claw-shaped magnetic poles disposed circumferentially on an outer circumferential side of said field winding, said claw-shaped magnetic poles being magnetized by said magnetic flux generated by said field winding; and a stator provided with: a cylindrical stator core supported by said case so as to envelop said rotor, a plurality of slots extending axially being formed in said stator core so as to line up circumferentially; and a stator winding installed in said stator core, wherein said stator core is constructed by laminating a magnetic steel plate, said stator core being provided with: a cylindrical base portion; a plurality of tooth portions disposed so as to extend from said base portion toward an axial center; and said plurality of slots, each of said slots being defined by said base portion and an adjacent pair of said tooth portions; ventilation channels are formed by a coil end group of said stator winding and said tooth portions of said stator core, a cooling airflow generated by rotation of said rotor flowing through each of said ventilation channels in a radial direction from an inner circumferential side; and each of said tooth portions is formed such that a radial length ht and a width bt thereof satisfy an expression 0.15