Patent ID: 6515398
Filing Date: 2003-02-04
Classification: H02K

Abstract:
An alternator, comprising:a housing; a stator fixedly housed in the housing; a rotor having a rotor shaft rotatably supported in the housing and disposed inside of the stator with an air gap therebetween; slip-rings mounted on a rear end of the rotor shaft; a brush device disposed around the slip-rings, the brush device including brushes slidably contacting the slip-rings for supplying exciting current to the rotor, a brush holder for holding the brushes therein, and a substantially cylindrical slip-ring cover connected to the brush holder; and a rear cover for covering an axial rear end of the brush device, wherein: the brush device and the rear cover provide a circumferential space surrounding and enclosing the slip rings therein; the rear cover includes a ventilation passage, formed on its surface facing the brush device, for ventilating the circumferential space; the ventilating passage is labyrinth-shaped; one end of the ventilation passage is open to the circumferential space and the other end of the ventilation passage is open to an outside space of the brush device; and the rear cover further includes a fringe wall formed around the other end of the ventilation passage that opens to the outside space of the brush device, the fringe wall extending in the axial direction of the rotor shaft.