| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent a rotor cylindrical body and a stator cylindrical body from being approached abnormally or brought into contact with each other in a vacuum pump equipped with a screw groove pump part. SOLUTION: In a composite type turbomolecular pump equipped with a screw groove pump part, formed out of a rotor cylindrical body 12, and of a stator cylindrical body 22 in such a way that a screw is formed in the inner circumferential surface 22a of the stator cylindrical body 22 to be formed into the screw groove pump part, an air gap sensor detecting an air gap formed between the outer circumferential surface 12a of the rotor cylindrical body 12 and the inner circumferential surface 22a of a stator cylindrical body 22 is fitted to the inner circumferential surface 22a adjacent to the lower end of the stator cylindrical body 22. |
