| 摘要 |
PURPOSE:To reduce oscillation and noise and to make a device small-sized by supporting a journal load with two fluid dynamic pressure bearings and supporting a thrust load with a point contact thrust bearing. CONSTITUTION:The lower end face of a revolving shaft 1 is brought into contact with a pole 22 of a thrust bearing 21 provided in the center part of a stator structure 13, and the thrust load which acts in the axial direction of the revolving shaft 1 by the weight of a rotary drum 5 is supported. Fluid dynamic pressure bearings 20 and 20' consist of a bearing structure 18 fitted into a bearing housing 12 and many narrow and shallow grooves 19 and 19' which are provided in a part of the revolving shaft 1 to face the bearing structure 18. When the revolving shaft 1 is rotated, a fluid is drawn into the space between the bearing structure 18 and the revolving shaft 1 along grooves 19 and 19', and a fluid dynamic pressure is generated there to give a centripetal force to the revolving shaft 1, and the revolving shaft 1 is supported without contacting. The journal load acting upon the revolving shaft 1 is supported by this centripetal force. Air, grease, or the like is desirable as the fluid. Thus, the solid contacting part of the bearing part is reduced, and oscillation and noise for rotation are reduced considerably. |
