1. Field of the Invention
The present invention relates to a noise reduction structure of an ac generator for a vehicle.
2. Description of the Related Art
A rotor of an conventional ac generator has a pair of pole cores having a base portion and a plurality of claw pole pieces extending axially from the base portion disposed at opposite ends of the rotor. A stator core of a conventional ac generator has a plurality of coil ends extending from opposite ends thereof to surround the circumference of the claw poles. A centrifugal cooling fan is fixed to an end of the rotor to cool the plurality of coil ends.
It has been found that fan noise is caused when circulating air C1, as shown in FIG. 2, driven by such a centrifugal cooling fan is interrupted by inner peripheral surfaces C2 of the coil ends surrounding the centrifugal fan.