| 摘要 |
PROBLEM TO BE SOLVED: To improve rotational characteristics of a motor and the service life of an oil-retaining bearing. SOLUTION: A fitting part 52 of a boss type which faces downward is formed integrally with the lower surface inner periphery of a rotor yoke 39. An annular oil retaining bearing 51 is fitted in the fitting part 52 and supported by a rotor yoke 39 in such a manner that when a shaft 35 rotates, the oil retaining bearing 51 rotates together with an inner ring 36a of a ball bearing 36, a rotor hub 38, and a rotor yoke 39, interlocked with the shaft 35, and slides on an outer ring 36b of the ball bearing 36. Since the oil-retaining bearing 51 slides on the outer peripheral surface of the outer ring 36b of the ball bearing 36, a part member such as the bearing holder turning to a factor causing rotating vibration of a motor as in the conventional case is not interposed between the ball bearing 36 and the oil retaining bearing 51, stable motor rotation is obtained, and the service life of the oil retaining bearing can be improved.
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