Alternating current generator for vehicles

An alternating current generator for vehicles comprising:

• a stator about which an armature winding is wound;
• a rotor including a Lundell type core disposed facing the inner periphery of the stator and a magnetic field winding wound about the Lundell type core;
• first and second cooling fans which are fixed to an axial end surface of the Lundell type core and generate cooling air along with rotation of the rotor;
• and
• a fan base which is formed separately from the first and second cooling fans, and is disposed between the second cooling fan and the Lundell type core and regulates the cooling air, wherein:
• the Lundell type core includes a plurality of U-shaped clearances formed in an outer periphery of the axial end surface, being spaced apart from each other in the circumferential direction;
• and
• the fan base includes a plurality of large-diameter portions and small-diameter portions alternately disposed in the circumferential direction, with at least one small-diameter portion being disposed confronting the U-shaped clearance in the axial direction.