| 摘要 |
A blower includes a durable and quiet bearing structure which eliminates or reduces rotational run out, and a bearing wherein the number of essential components and cost for manufacturing is reduced, and the diameter of the shaft can be increased. The blower has an impeller adapted to be rotated upon energizing the blower. The blower has a bearing apparatus which supports the rotational center portion of the impeller, in which the bearing apparatus has a sleeve, and a stepped shaft including a larger diameter portion and a reduced diameter portion provided at one end thereof. A first rolling contact groove is formed at an appropriate position on the outer peripheral surface of the larger diameter portion. A second rolling contact groove is formed on an inner peripheral surface of the sleeve so as to correspond with the first rolling contact groove. Balls of a first row are interposed between the first and second grooves, and an inner race fits over the reduced diameter portion and is secured thereto with an appropriate preloading force. A third rolling contact groove is formed around an outer peripheral surface of the inner race. A fourth rolling contact groove is formed on the inner peripheral surface of the sleeve so as to correspond with the third rolling contact groove. Balls of a second row are interposed between the third and forth grooves.
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