| 摘要 |
The present invention provides a fluid dynamic bearing device having high durability and capable of being produced at low cost. In the fluid dynamic bearing device, a housing ( 7 ) and a disc hub ( 3 ) are resin molded parts, and a thrust bearing gap is formed between an upper end surface ( 7 d) of the housing ( 7 ) and a lower end surface ( 3 e) of the disc hub ( 3 ). In this case, the surfaces ( 7 d , 3 e) function as sliding portions (P) temporarily in sliding contact with each other during operation of the bearing. A diameter of PAN-based carbon fibers blended as reinforcement fibers in the resin housing ( 7 ) is 12 mum or less, and the blending amount is within a range of 5 to 20 vol %, thereby making it possible to prevent occurrence of flaws and wear in the sliding portions (P).
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