| 摘要 |
PROBLEM TO BE SOLVED: To reduce blade vibrations by forming either a dynamic blades or static blades, or both, provided on a rotor that is rotatably driven by a motor so that the blade angle with respect to a line in a circumferential direction becomes the greatest on an inner diameter section and it becomes continuously or intermittently smaller toward an outer diameter section. SOLUTION: When this turbo molecular pump is run, a motor 12 is driven by energizing each of magnetic bearings 9 through 11 and by lifting a pump rotation section consisting of a rotary shaft 7, a rotor 6 with dynamic blades 5, and other elements. During this time, dynamic blades 5 turn through static blades 4 and, at the same time, a thread groove pump stage 8 turns so that it faces an inner peripheral surface of a seal ring 14, as a result of the pump rotation section turning at high speeds. With dynamic blades 5, the blade angle in the blade length direction is set so that the exhaust velocity becomes the greatest in each part of the dynamic blade in the blade length direction. This maintains the maximum exhaust velocity in each part of the dynamic blade in the blade length direction to allow the blade surface to be effectively used for exhaust, thereby realizing highly efficient exhaust performance even in a large-sized pump with a large outer diameter of the rotor 6. |
