Patent ID: 6499942
Filing Date: 2002-12-31
Classification: F04D,F05D

Abstract:
A turbomolecular pump comprising: an inlet port into which a gas is introduced; an outlet port from which the gas is expelled; a motor; a rotor having plural rotor blades and being rotatably driven by the motor for pumping the gas from the inlet port to the outlet port; a plurality of stator blades confronting the rotor blades with a small gap between confronting stator and rotor blades; a bearing for rotatably supporting the rotor; and a casing for housing the motor and the stator blades; wherein the rotor blades and the stator blades are oriented at a given angle with respect to the direction of rotation of the rotor blades, and respective ones of at least one of the rotor blades and the stator blades are formed so that the angles of orientation of the blades on a first surface of the blades facing the direction of rotation of the blades differ between the inlet port side of the blades and the outlet port side of the blades, and on a first side of the first surface of the blades closer to the inlet port the blades have a larger angle of orientation than on a second side of the first surface closer to the outlet port; wherein at least one side of respective ones of the blades facing the direction of rotation of the rotor blades has a plurality of surfaces each having different angles with respect to the direction of rotation of the rotor blades; and wherein the angles of orientation of the respective surfaces are in the range of 20Â° to 50Â° on the inlet port side of the blades, in a range of 10Â° to 40Â° on an intermediate portion of the blades, and in a range of 10Â° to 90Â° on the outlet port side of the blades.