Vakuumpumpe

摘要

The present invention provides a vacuum pump in which a damaging torque produced when a rotating rotor (6) crashes into the inner wall of a pump case (1), is prevented to transfer to a vacuum chamber (200) so as to protect the vacuum chamber. Bolt-holes of flange portions (1a), through which the vacuum pump (100) and the vacuum chamber and also the pump case and a base member (4) disposed below the pump case are fastened, respectively, are formed so as to have larger diameters than the shank diameters of corresponding bolts by 20% or more. With this arrangement, when the entire vacuum turns moved by the damaging torque, the pump case slips relative to the vacuum chamber and the base member by the gaps between the pump case-base member fastening bolt-holes and the pump case-base member fastening bolts. As a result, the damaging torque is absorbed and is prevented to transfer to the vacuum chamber.