Patent ID: 8591204

Claim:
A turbo-molecular pump, comprising: a base; a rotor rotatably supported on the base; a stator disposed around the rotor; and a cylindrical outer casing configured to accommodate the stator, having a flange surface of the outer casing; wherein the stator comprises multiple stages of stator blades and spacers alternately stacked one upon another in an axial direction from a first stage of the stator to a last stage of the stator, the spacers being held between a flange surface of the base and the flange surface of the outer casing, and at least one of the spacers is integrately provided with a casing part that covers an outermost circumferential surface of at least one of other spacers inside the outer casing, the one the spacers and the casing part being formed as a monolithic piece; wherein the at least one of the spacers makes contact with the flange surface of the outer casing, and has a plane of contact with a first stage stator blade; and all portions of the at least one spacers between the flange surface of the outer casing and the plane of contact are homogeneous.