Turbo-molecular pump and stator

Abstract

A turbo-molecular pump comprises: multiple stages of rotor blades formed with multiple blades and provided in a pump axial direction; and multiple stages of stator blades provided with multiple blades, the multiple stages of the rotor blades and the multiple stages of the stator blades being alternately arranged in the pump axial direction. Each stage of the stator blade includes multiple divided stator blades, and a clearance is formed at a portion where the multiple divided stator blades face each other, and circumferential phases of the clearances of adjacent ones of the stages of the stator blades in the pump axial direction are shifted from each other.

What is claimed is: 
     
         1 . A turbo-molecular pump comprising:
 multiple stages of rotor blades formed with multiple blades and provided in a pump axial direction; and   multiple stages of stator blades provided with multiple blades, the multiple stages of the rotor blades and the multiple stages of the stator blades being alternately arranged in the pump axial direction,   wherein each stage of the stator blade includes multiple divided stator blades, and a clearance is formed at a portion where the multiple divided stator blades face each other, and   circumferential phases of the clearances of adjacent ones of the stages of the stator blades in the pump axial direction are shifted from each other.   
     
     
         2 . The turbo-molecular pump according to  claim 1 , wherein
 each rotor blade includes the multiple blades arranged at a predetermined interval in a circumferential direction, and   in a case where an angle between adjacent ones of the blades of each rotor blade in the circumferential direction is a single-pitch angle, an amount of shift between the circumferential phases of adjacent ones of the stages of the stator blades in the pump axial direction is set greater than the single-pitch angle.   
     
     
         3 . The turbo-molecular pump according to  claim 1 , wherein
 the amount of shift between the circumferential phases of adjacent ones of the stages of the stator blades is set to 90 deg.   
     
     
         4 . The turbo-molecular pump according to  claim 1 , further comprising:
 multiple spacer rings provided such that the multiple spacer rings and the multiple stages of the stator blades are alternately stacked on each other in the pump axial direction,   wherein each spacer ring includes a position adjustment member configured to adjust the circumferential phases of adjacent ones of the stator blades in the pump axial direction.   
     
     
         5 . A stator used in a turbo-molecular pump comprising a rotor and the stator, wherein the rotor includes multiple stages of rotor blades formed with multiple blades and provided in a pump axial direction, and the stator includes multiple stages of stator blades provided with multiple blades, the multiple stages of the rotor blades and the multiple stages of the stator blades being alternately arranged in the pump axial direction,
 wherein each stage of the stator blade includes multiple divided stator blades, and a clearance is formed at a portion where the multiple divided stator blades face each other, and   circumferential phases of the clearances of adjacent ones of the stages of the stator blades in the pump axial direction are shifted from each other.   
     
     
         6 . The stator according to  claim 5 , wherein
 each rotor blade includes the multiple blades arranged at a predetermined interval in a circumferential direction, and   in a case where an angle between adjacent ones of the blades of each rotor blade in the circumferential direction is a single-pitch angle, an amount of shift between the circumferential phases of adjacent ones of the stages of the stator blades in the pump axial direction is set greater than the single-pitch angle.   
     
     
         7 . The stator according to  claim 5 , wherein
 the amount of shift between the circumferential phases of adjacent ones of the stages of the stator blades is set to 90 deg.