| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem in conventional rotors of alternator that a fan is so formed to axially protrude from an end face of a rotor and the rotor is cooled thereby; however in this rotor, cost for the manufacturing the fan and cost for assembling thereof are required, and the fan is axially protruded and a space need be accordingly ensured in the axial direction, which prevents downsizing of alternators. SOLUTION: Through holes 8 are formed in a rotor 3 which through holes extend from one end face (face A) to the other end face (face B) in the direction of the axis of the rotor so that the holes are twisted. A plurality of the through holes 8 are symmetrically positioned about a rotating shaft 4. Since the through holes 8 are twisted in the axial direction, the condition of air in proximity to the openings 8A of the through holes on one side are made to differ from the conditions of air in proximity to the openings 8B on the other side when the rotor is rotated. On this account, a flow of air going from the openings on one side to the openings on the other side is formed, and the rotor is thereby cooled.
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