PURPOSE: To improve the cooling performance of rotary electric machine by disposing a second housing in the form of concentric circle with a first housing and by disposing several ribs between the outer perimeter of the first housing and the inner perimeter of the second housing.
CONSTITUTION: A second housing 21b is formed to a cylindrical shape with both the ends open in axial direction and a plurality of inner ribs 21c are provided at the inner perimeter; a first housing 21 having a concentric circle shape is provided in such a manner that this housing touches the inner perimeter of the inner ribs and also touches the outer perimeter of a stator 3; and an air vent passage 22 is formed with the inner perimeter of the second housing 21b, an inner ribs 21c and the first housing 21a. Since the stator 3 is covered and enveloped with the first housing 21a made of an aluminum alloy having good thermal conductivity, heat generated in the stator 3 is immediately transmitted to the first housing 21a. As a result, the first housing 21a comes into contact with the stator 3 within a large area, so that heat transfer to the first housing 21a becomes extremely good and this heat is cooled with an air flow passing through the air vent passage 22 thereby cooling very effectively.
IMAI AKIO
NARUGE YOSHINORI
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