| 摘要 |
PROBLEM TO BE SOLVED: To provide a dynamic pressure bearing of a simple structure capable of eliminating the half whirl, having a shaft which has no directionality, and positively communicating the fluid to a radial bearing part. SOLUTION: A bearing opposite face of one of a shaft 1 and a sleeve 11 forming a bearing part, is formed into the multirobe shape having one or more expanded deformation parts when observed from its cross section, and the deformation parts are spirally formed to be circumferentially moved following the movement along the axial direction of the shaft 1 or the sleeve 11. The deformation parts are formed by the expanding force by a projecting part 3 of a core 2 inserted into a shaft hollow inner peripheral part, or the pressing force by a projecting part 13 of a hub 12 fitted to an outer peripheral part of the sleeve 11. One deformation part, or plural deformation parts having the predetermined phase difference are formed on the bearing opposite face, and circularity of the bearing cross section including the deformation parts is set approximately 2μm or less, preferably 1μm or less.
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