Patent ID: 7059823

Claim:
A molecular pump comprising: a casing having a gas inlet port and a gas discharge port; a stator disposed within the casing; a shaft disposed in the casing concentrically with the stator; a bearing rotatably supporting the shaft for undergoing rotation relative to the stator in a preselected direction of rotation; a rotor mounted on the shaft for rotation therewith in the preselected direction of rotation; a motor for rotationally driving the shaft; and a flange connected to the casing at the gas inlet port, the flange having a plurality of mounting holes each for receiving a fastener and a buffering portion for undergoing deformation due to a shock resulting from a torque acting on the casing in the preselected direction of rotation, the buffering portion having a plurality of deformable thin-wall portions disposed adjacent to the respective mounting holes in a direction opposite to the preselected direction of rotation.