| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing of ceramic capable of preventing linking or seizure to preclude damage of the ceramic material and accomplishing stable rotation. SOLUTION: The flatness of the end-face dynamic pressure generating parts 7a and 7b in vertical direction of an outer cylinder 7 is set to a range under 3μm. Also the flatnesses of an end-face dynamic pressure generating part 21a below the upper thrust plate 21 and an end-face dynamic pressure generating part 21b over the lower thrust plate 23 are set to a range under 3μm. In the parts 7a and 7b, the outer cylinder 7 is arranged so that the inside surface 7d is positioned higher in the range 0-2.5μm than the outermost peripheral part 7c. The two thrust plates 21 and 23 are made from flat plate, having no level difference between the inside surface and the outermost peripheral part.
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