| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydrodynamic bearing device which can achieve a stable thrust floating-up characteristic even when the temperature in a working environment changes. SOLUTION: The clearance A at a thrust dynamic pressure generating groove surface, the clearance B at the oil sump portion on the outer circumferential surface of a flange 3, the clearance C between the surface of the flange 3 on the side of a sleeve 1 and the sleeve 1, the clearance G at radial dynamic pressure generating groove portions, the clearance D at the oil sump portion between the G portion and the C portion, and the clearance H at the oil sump portion neighboring with the G portion on the open side of the bearing satisfies the following relations, G<H, A<B, A<D, C<B, C<D, B<H, D<H, and the viscosity of the base oil of lubricating oil or grease at 40°C is 4 cSt or higher, The stable thrust floating-up characteristic can be achieved by fixing one of the outer periphery of the sleeve 1 and the outer periphery of a shaft 2 to a base 6, and by fixing the other of them to a rotatable hub rotor 7. COPYRIGHT: (C)2009,JPO&INPIT
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