| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotary electric machine with sufficient ventilation characteristics which do not depend on a sound absorption member without expanding a sound of a noise source. SOLUTION: The rotary electric machine includes a fan cover for sucking air from a suction port of the fan cover by rotating a plurality of blades in the fan cover and discharging the air from an outlet under the guidance of a guide cylinder of the fan cover. Since the rotary electric machine is rotated so that an outside of a range of f<SB>0</SB>±0.35f<SB>0</SB>to a resonance frequency f<SB>0</SB>of a space in the fan cover is set to an antiresonance frequency f<SB>r</SB>, and the frequency of a blade rotating sound generated by rotating the blade of the fan for the rotary electric machine having the plurality of the blades in the fan cover (f<SB>Z</SB>=rotating frequency F×number Z of blades of fan) becomes near the antiresonance frequency f<SB>r</SB>, the noise can be effectively reduced. And, since a silencer of the sound absorbing member or a double cover, etc. for reducing the noise is not required, the rotary electric machine can be constituted with a long lifetime and a low cost. COPYRIGHT: (C)2005,JPO&NCIPI
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