Rotating electric machine with a cooling structure

A rotating electric machine comprising:

• a housing;
• a pair of bearings that is fixed by the housing;
• a shaft that is supported at opposite ends thereof by the respective bearings;
• a rotor that is mounted on the shaft for rotation therewith;
• and
• a stator that is fixed by the housing and disposed in such a manner as to surround the rotor, wherein
• a rotational speed detection gear is mounted on the shaft for rotation therewith at a position between the rotor and one of the bearings and in a vicinity of the bearing, and the rotational speed detection gear has a plurality of gear teeth at an outer circumference thereof,
• a rotational speed detector is provided at a position in the housing so as to face the gear teeth of the rotational speed detection gear,
• a rotating member for generating a flow of air is disposed in the housing,
• the housing includes a cylindrical peripheral wall and opposite end walls,
• one of the end walls is a gear-side end wall that is adjacent to the rotational speed detection gear, and the gear-side end wall has at a position adjacent to the shaft an air intake port that provides communication between inside and outside of the housing,
• a recess is formed in the gear-side end wall, the recess extending radially outward to an outer periphery of the end wall from the air intake port to form an air intake passage,
• an air outlet port is provided in the cylindrical peripheral wall of the housing between the gear-side end wall and the stator to provide communication between the inside and the outside of the housing,
• the rotational speed detection gear is disposed on the way of an air path extending from the air intake port to the rotating member along an axis of the shaft, and
• an air passage hole is formed through the rotational speed detection gear along the axis of the shaft, and
• an air flow generator is provided in the vicinity of the air passage hole of the rotational speed detection gear so that when the rotational speed detection gear is rotated in a predetermined direction, air flows from the bearing side of the rotational speed detection gear to the side thereof opposite to the bearing.