| 摘要 |
PROBLEM TO BE SOLVED: To prevent the leakage of the lubricant outside due to the impact of a fall and the adhesion thereof to a disc by coating a top surface of a thrust receiver plate and a lower surface of a thrust cover with the oil repellent agent, and specifying the relation between a boss, the thrust receiver plate and the thrust cover. SOLUTION: A top surface of a thrust receiver plate 18 and a lower surface of a thrust cover 18 abutting on the top surface of the thrust receiver plate 16 are coated with an oil repellent agent 19. A boss 12 is provided with a stepped shape having inner diametersϕd1,ϕd2 downward from an upper end surface at an upper end surface side outer diameter part of the boss 12, and a thrust cover 18 is provided with a recessed part at a lower surface side thereof, and in the case where the most inside diameter of the thrust cover 18 is expressed withϕd3, the inner diameter of the recessed part of the thrust cover 18 is expressed withϕd4, and the inner diameter of the thrust receiver plate 16 is expressed withϕd5, the inner diameters are set so as to satisfy the relation thatϕd1<ϕd3<ϕd2<ϕd5<ϕd4. With this structure, even in the case where the lubricant is leaked out of the bearing by the impact of a fall, the lubricant is stored in a space 23 without leaking outside. Adhesion of the leaked lubricant to the plural discs provided in the periphery of a hub 14 is prevented, and the normal recording and replaying operation can be performed.
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