| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise in an in-wheel motor 10 having a rotor of arranging and fixing a plurality of permanent magnets 56 in a row in the peripheral direction on a ring surface 54, and bipolar stator coils 63 and 72, by forming a central hole 52b for penetrating a wheel shaft 30 through the center of a bottom surface 52, with a bottomed cylindrical shape composed of the bottom surface 52 and the ring surface 54 erected on the bottom surface peripheral edge. SOLUTION: Four through-elongate holes 52d are formed at an equal angle interval in the bottom surface of a rotor body 51, or a perforated part or a weight part and an non-perforated part or a non-weight part dislocated by 45 degrees from this perforated part or the weight part, are formed in the rotor body 51 by installing a mass body 58. A primary resonance frequency is different between the perforated part or the weight part and the non-perforated part or the non-weight part. Since the primary resonance frequency of the perforated part or the weight part and the non-perforated part or the non-weight part separates, secondary resonance vibrational energy of the rotor 50 reduces, and the noise caused by primary resonance vibration of the rotor 50 can be reduced. COPYRIGHT: (C)2009,JPO&INPIT
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