MOLECULAR PUMP

摘要

PROBLEM TO BE SOLVED: To provide a molecular pump with less magnetic field leaking out of a turbo molecular pump along a shaft. SOLUTION: The shaft is formed by bonding a non-magnetic part 31 constituted of a non-magnetic member with a magnetic part 32 formed of highly permeable material such as iron. The magnetic part 32 comprises a rotor motor unit 34 for a DC brushless motor and electromagnetic targets 33 and 34 for a magnetic bearing. Since the rotor motor unit 34 is formed on the magnetic part 32, the power of the DC brushless is not degraded. A non-magnetic part 36 is formed on an inlet side of the turbo molecular pump to reduce the leakage of the magnetic force formed in the magnetic body 32 into a vacuum device via the inlet.