Patent ID: 7341423

Claim:
A molecular pump attached to a vacuum vessel for exhausting gas from the vacuum vessel, comprising: a casing having a stator and provided with an inlet and an outlet; a rotor rotatably supported in the casing and cooperating with the stator for transferring gas from the inlet to the outlet; a motor for rotating the rotor; a flange attachment portion connected to an end portion of the casing and having a fastening hole extending through the flange attachment portion in the thickness direction and an elongated hole extending from the fastening hole in a direction opposite to the rotation direction of the rotor; a buffering member having a buffering portion that transforms and absorbs shock energy due to abnormal torque generated during malfunction of the molecular pump, a first fixing portion provided at one end of the buffering portion and having a fastening hole, and a second fixing portion provided at the other end of the buffering portion; fastening means for fastening the buffering member to the vacuum vessel via the fastening hole in the flange attachment portion and the fastening hole in the buffering member; and fixing means for fixing the second fixing portion of the buffering member to the flange attachment portion but not to the vacuum vessel.