| 摘要 |
PROBLEM TO BE SOLVED: To provide a turbo-molecular pump free of such an occurrence that Joule's heat is generated from the rotary shaft owing to its rotation to result in a temperature rise. SOLUTION: The inner ring IL of a touch-down bearing TB1 is made of a material having a low density of residual magnetic flux. Accordingly no magnetization of inner ring IL will take place even if magnets 5N and 5S of the rotary shaft 5 penetrate the touch-down bearing TB1 when pump is to be assembled, and no Joule's heat is generated from the rotary shaft despite its rotation, and it is possible to prevent the rotary shaft 5 and rotor blades 5B from getting a high temperature.
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