Turbo machine

Abstract

A turbomachine has a shaft extending along and rotatable about an axis and having an outer surface, a first impeller wheel permanently mounted on the shaft and having a respective back face, a second impeller wheel detachably mounted on the shaft axially offset from the first impeller wheel and having a respective back faces axially confront the back face of the first impeller wheel, and respective first and second axial bearings each having a respective rotor bearing half fixed to the respective impeller wheel and a respective nonrotatable stator bearing half axially juxtaposed with the respective rotor bearing half. The rotor shaft is of increasingly smaller cross-sectional size from the first wheel to the second wheel.

1 . A turbomachine comprising:
 a support;   a shaft extending along and rotatable relative to the support about an axis and having an outer surface;   a first impeller wheel permanently mounted on the shaft and having a respective back face, the outer surface of the shaft being formed with steps of increasingly small diameter away from the first wheel;   a second impeller wheel detachably mounted on a respective one of the steps of the shaft axially offset from the first impeller wheel and having a respective back face axially confronting the back face of the first impeller wheel;   respective first and second axial magnetic bearings each having a respective annular rotor bearing half fixed to the respective impeller wheel and a respective one-piece nonrotatable annular stator bearing half axially juxtaposed with the respective rotor bearing half, axially spacedly traversed by the shaft, and carried on the support;   a radial bearing mounted on the rotor shaft between the axial bearings and having an inner rotor ring carried on a respective one of the steps and an outer stator ring carried on the support.   
     
     
         2 . The turbomachine defined in  claim 1 , wherein the first radial impeller wheel is shrunk onto the rotor shaft. 
     
     
         3 . The turbomachine defined in  claim 1 , wherein the stator bearing halves each have a one-piece support having an axially throughgoing hole through which the rotor shaft passes. 
     
     
         4 . The turbomachine defined in  claim 1 , wherein at least one of the radial impeller wheels is formed by an impeller wheel body including a blade system and a disk of a different material mounted on the rear side of the impeller wheel body, the disk forming the rotor bearing half of the respective axial bearing. 
     
     
         5 . The turbomachine defined in  claim 1 , wherein the first radial impeller wheel is fixedly mounted together with further machine components in a main housing, the rotor shaft extending out of the main housing, the second radial impeller wheel being mounted outside the main housing. 
     
     
         6 . The turbomachine defined in  claim 1 , wherein an electric machine is provided between the radial impeller wheels. 
     
     
         7 . The turbomachine defined in  claim 1 , wherein both radial impeller wheels are mounted overhung at respective ends of the rotor shaft.