Patent ID: 7105960

Claim:
A generator comprising: a case including two end walls in an axial direction and a peripheral side wall connected to the two end walls, wherein the case has a plurality of first opening portions which are provided in at least one of the two end walls and open approximately in the axial direction, and a plurality of second opening portions which are provided in the peripheral side wall and open approximately in a radial direction that is perpendicular to the axial direction; a stator disposed in the case coaxially with the axial direction of the case, the stator having an armature coil wound thereon; a rotor rotatably supported at an inner peripheral side of the stator; a housing which accommodates the rotor; a commutator which converts AC electromagnetic force induced in the armature coil to DC electromagnetic force, wherein the commutator is located adjacent to the housing and is covered by the case; a fan disposed at one axial end portion of the rotor and rotating together with the rotor to draw outside air outside the case through the first opening portions and to discharge the drawn outside air through the second opening portions; and a cover member which covers at least part of the first opening portions from an outside of the case with clearances between the cover member and the case.