| 摘要 |
PURPOSE:To realize a bearing stable against variation of temperature and attitude by employing high viscosity fluid as the lubricant for dynamic thrust bearings provided at the opposite ends of rotary member while employing low viscosity fluid as the lubricant for other thrust bearing. CONSTITUTION:A seat 8' is fixed above a shaft member 2' secured to a lower cylinder 1 while radial bearings 16R, 17R employing high viscosity fluid such as oil or grease as lubricant are provided on the shaft member 2'. While a dynamic pressure thrust bearing 16S employing high viscosity fluid as lubricant and a dynamic pressure thrust bearing 17S employing low viscosity fluid such as air are provided at the opposite ends of the shaft member 2'. The thrust shaft 16S is constructed with a seat 8', a shallow spiral groove 19 etched in at least one surface facing against an auxiliary rotary member 3 and lubricant of high viscosity fluid filled between the facing surfaces. |
