| 摘要 |
<p>PROBLEM TO BE SOLVED: To decrease the viscosity change of a lubricant in long-term use by filling a bearing gap between a shaft and a sleeve freely rotatably fitted to each other with a lubricant prepared by using, as the base oil, an oil mixture comprising a plurality of components having the same or approximately the same vapor pressure. SOLUTION: This bearing apparatus has a shaft 2 rotating integrally with a rotatable polygon mirror 1 having a plurality of reflection planes 1a and has a sleeve 3 freely rotatably fitted to the shaft 2, the sleeve being united to a bearing housing 4. At the lower end of the sleeve 3, a thrust plate 6 having a spherical body 6a for supporting the lower end of the shaft 2 in the thrust direction is fixed, and a flange 7, which is a rotating member, is fixed to the upper part of the shaft 2. A bearing gap between the shaft 2 and the sleeve 3 is filled with a lubricant 11 prepared by using, as the base oil, an oil mixture comprising a plurality of components having the same or approximately the same vapor pressure. The difference in vapor pressure of the components is preferably 5×10-5 Torr or lower at 0-60 deg.C.</p> |
