| 摘要 |
PURPOSE:To eliminate a spring and to save adjusting by providing mechanism for applying pre-pressure between the bottom wall of housing and a bearing while applying proper axial pre-pressure of atmosphere in an atmospheric chamber onto the bearing through a bearing stopper member having a pressure receiving face. CONSTITUTION:Mechanism 13 for applying proper axial pre-pressure of atmosphere in an atmospheric chamber 15 through a bearing stopper member 14 onto the bearings 7, 8 is provided between the bottom wall 1a' of housing and the bearing 8. Atmospheric air is fed continuously through a hole 18 into said chamber 15. Upon high speed rotation of rotor drive shaft 5 through a motor 9, the rotor blade 6a will rotate integrally with high speed thus to evacuate the vacuum chamber 2. Consequently, the differential pressure produced between the vacuum chamber 2 and the atmospheric chamber 15 will cause application of proper axial pre-pressure onto the bearings 7, 8 through a shaft stopper member 14 having a pressure receiving face 16. As a result, spring load regulation is not required to save manpower required for adjusting while the spring is not required to reduce the number of parts and the price.
|
