| 摘要 |
PROBLEM TO BE SOLVED: To prevent leaking of lubricating oil in a fluid dynamic-pressure bearing mechanism. SOLUTION: In the fluid dynamic-pressure bearing mechanism used in a small spindle motor, a shaft 22 is supported by a radial dynamic pressure generated by a radial gap 261 and a thrust dynamic pressure generated by a thrust gap. A tapered seal part 271 is formed between an outer side face 253 of an upper cap 25 covering a top part of a sleeve and an inner side face 2414 of the annular tapered part 2412 of a housing member 241, and the lubricating oil is held in a bearing mechanism interior by using capillary action. The upper cap 25 is formed by press working, and a plating layer is formed on the outer side face 253 contacting a boundary face of the lubricating oil. By this, a flaw caused on the outer side face 253 due to sliding contact during drawing from a die in the press working is covered by the plating layer, spread of the lubricating oil is prevented, and the leakage of the lubricating in the fluid dynamic-pressure bearing mechanism is prevented. COPYRIGHT: (C)2010,JPO&INPIT
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