Patent ID: 8089193

Claim:
An alternator for use in an automotive vehicle comprising: a housing composed of a front frame and a rear frame; a stator fixed in the housing; a rotor rotatably disposed in the stator, the rotor including slip-rings; a brush device supporting brushes slidably contacting the slip-rings, the brush device including a slip ring cover covering the slip-rings; and a rear cover covering the brush device and other electric components mounted on a rear surface of the rear frame, the rear cover being connected to the rear frame, wherein: the rear cover includes a surrounding wall surrounding the brush device, the surrounding wall including a plurality of partial walls having respective radiuses from a rotational axis of the rotor; and some of the plurality of partial walls are positioned downward of the rotational axis of the rotor when the alternator is mounted on the automotive vehicle, wherein the rear cover includes a plurality of windows for introducing cooling air, the windows being positioned radial outside of the surrounding wall, the rear cover and the rear frame provide a space for the brush device, and the plurality of windows are provided to introduce the cooling air into the space.