| 摘要 |
PROBLEM TO BE SOLVED: To provide a molecular pump which solves such a problem that it is adversely affected when a rotary member 4 is fractured by corrosion and there occurs a torque in a casing 5 or a lower casing 9. SOLUTION: Notch portions 5K are provided near opposite sides of a through hole 5H for a bolt 11 bored in an inlet flange 5F, ideally near opposite sides in the circumferential direction of a pitch circle concentric with the through hole 5H. With such structure, thin portions T are formed near the through hole 5H, the thin portions T constituting deformable portions. Since the molecular pump has the above construction, when the torque which has occurred acts on the thin portions T through the bolt 11, the inlet flange 5F having the thin portions T at its central portion distorts, and the energy acting on the bolt 11 is absorbed by the deformation of the notch portions K. COPYRIGHT: (C)2005,JPO&NCIPI |
