| 摘要 |
PURPOSE:To maintain the rigidity of a dynamic-pressure pneumatic bearing so as to obtain a dynamic-pressure pneumatic bearing motor into which dirt and dust that cause insufficient rotation hardly enter by forming an air reservoir having a volume larger than the gap between a rotating body and bearing member on the inner peripheral surface of the bearing member or outer peripheral surface of the rotating body and allowing the air reservoir to communicate with the dynamic-pressure air bearing only. CONSTITUTION:An annular air reservoir 21 which supplies air to a dynamic-pressure pneumatic bearing 7 and has a volume larger than the gap between the outer peripheral surface 3 of a rotating body 1 and the inner peripheral surface 6 of a bearing member 4 is provided at the central part of the inner peripheral surface 6 of the member 4 constituting the bearing 7 between the body 1 and member 4. When the body 1 on which dynamic-pressure producing groups 23 are formed is rotated, the air in the member 4 is discharged to the outside along the groups 23 and a dynamic pressure is produced above and below the body 1. When the dynamic pressure is produced, counterflows are produced in the groups 23 due to a pressure drop in the reservoir 21 and the rigidity of the bearing 7 can be maintained, because the negative pressure in the reservoir 21 is reduced due to the saturation of the flowing out amount and counterflow amount. In addition, since dynamic-pressure producing air is supplied from the reservoir 21, insufficient rotation caused by dirt and dust entering from the outside can be prevented. |
