Patent ID: 7619336

Claim:
A vehicle-use generator driven by a vehicle engine at a rotating shaft thereof, comprising: a rotor rotatably mounted to the rotating shaft; a stator fixedly located radially outward of the rotor; a cooling fan fixed to the rotor to rotate together with the rotating shaft in order to generate cooling air for cooling said stator; and a housing that houses the rotor and the stator and rotatable supports said rotating shaft, the housing being provided with a plurality of ribs arranged in a circumferential direction of the rotating shaft so as to form a plurality of cooling air outlet windows; wherein the plurality of ribs are inclined with respect to a radial direction of the rotating shaft in a plane perpendicular to an axial direction of the rotating shaft, wherein the radial direction is a line extending from a center of the rotating shaft to a center of one rib of the plurality of ribs, and shaped such that widths of the ribs of the plurality of ribs are gradually changed cyclically in the circumferential direction, and wherein a ratio of a width of the narrowest one of the plurality of the ribs to a width of a widest one of the plurality of ribs is between 0.8 and 0.5.