| 摘要 |
PROBLEM TO BE SOLVED: To prevent rubbing and seizure due to shortage of an oil film in particular on an upper part of a dynamic pressure generating groove as a lubricant becomes short of sealing force with centrifugal force by a taper part. SOLUTION: An axis of rotation 3 has a taper part 3A a diameter of which becomes smaller toward a disc 6 on the opening end side of a sleeve 2 and has a screw sealing groove 2D in the same depth as the dynamic pressure generating groove on a bearing hole 2A continuously from the dynamic pressure generating groove 2B, a space between the taper part 3A and the screw sealing groove 2D facing against each other constitutes an oil reservoir part 3B, accordingly, the lubricant 5A is firmly sealed against the sleeve opening end by pumping force of the screw sealing groove 2D generated by torque and is supplied downward from above along the axial direction of the axis of rotation 3, certainly held in the dynamic pressure generating groove 2B, oil film shortage is not caused, and it is possible to provide stable rotation for a long period of time. |
