| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a dynamic pressure fluid bearing device promoting miniaturization, and capable of preventing over lifting of a shaft due to deformation of the shaft during screwing of a clamp screw into a screw hole. <P>SOLUTION: The shaft 5 is rotatably inserted in a bearing hole of a sleeve 3, the screw hole 10 for fastening a clamp on the shaft 5 is formed from an upper end of the shaft 5 along a direction of an axis 17, operating oil 16 is filled in a gap 21 between an inner circumferential face of the sleeve 3 and an outer circumferential face of the shaft 5, and radial bearing parts 26 and 27 formed with grooves for dynamic pressure generation are provided on the inner circumferential face of the sleeve 3. In an inner diameter of the sleeve 3, an inner diameter D1 in a predetermined range A from an opening upper end 3a is formed larger for a deformation anticipated amount ΔD in a radial direction of the shaft 5 in comparison with an inner diameter D2 in a range B in a lower end side than the predetermined range A. The predetermined range A is equivalent to a range from the opening upper end 3a of the sleeve 3 and including the radial bearing part 26 positioned in an upper end side. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
