Vacuum pump comprising an axial magnetic bearing and a radial gas foil bearing

Abstract

A vacuum pump and method of mounting a shaft within a vacuum pump is disclosed. The vacuum pump comprises a rotor and a stator. The rotor comprises a shaft comprising pumping elements extending therefrom. The shaft is mounted to rotate and is supported by a plurality of bearings, the plurality of bearings comprising: an axial magnetic bearing and two radial bearings, at least one of the two radial bearings comprising a gas foil bearing.

1 . A vacuum pump comprising a rotor and a stator, said rotor comprising a shaft comprising pumping elements extending therefrom;
 said shaft being mounted to rotate and being supported by a plurality of bearings, said plurality of bearings comprising:   two radial bearings, at least one of said two radial bearings comprising a radial gas foil bearing; and   an axial bearing, said axial bearing consisting of an axial active magnetic bearing.   
     
     
         2 - 4 . (canceled) 
     
     
         5 . The vacuum pump according to  claim 1 , wherein said two radial bearings comprise said gas foil bearing and a radial magnetic bearing said radial magnetic bearing being located close to a portion of said shaft supporting said pumping elements and said radial gas foil bearing being located remotely from said portion of said shaft supporting said pumping elements. 
     
     
         6 . The vacuum pump according to  claim 5 , wherein said radial magnetic bearing comprises a radial passive magnetic bearing. 
     
     
         7 . (canceled) 
     
     
         8 . The vacuum pump according to  claim 1 , said vacuum pump further comprising a seal to seal a portion of said vacuum pump comprising said pumping elements from a portion of said vacuum pump comprising said at least one radial gas foil bearing. 
     
     
         9 . The vacuum pump according to  claim 8 , said vacuum pump comprising a sealing element to seal a portion of said vacuum pump comprising said pumping elements and said magnetic bearing from a portion of said vacuum pump comprising said radial gas-foil bearing. 
     
     
         10 . The vacuum pump according to  claim 1 , said vacuum pump, further comprising a motor for rotating said shaft, said motor being mounted between said two radial bearings. 
     
     
         11 . The vacuum pump according to  claim 1 , said vacuum pump being configured to operate in an orientation where said shaft extends vertically and said axial magnetic bearing is configured to support and levitate said shaft. 
     
     
         12 . The vacuum pump according to  claim 1 , wherein said vacuum pump comprises a turbomolecular pump. 
     
     
         13 . A method of mounting a shaft of a rotor of a vacuum pump, said method comprising:
 supporting said shaft with an axial active magnetic bearing and with two radial bearings, at least one of said two bearings comprising a radial gas foil bearing.   
     
     
         14 . The method according to  claim 13 , wherein said two radial bearings comprise said gas foil bearing and a radial magnetic bearing, said radial magnetic bearing being located close to a portion of said shaft supporting said pumping elements and said radial gas foil bearing being located remotely from said portion of said shaft supporting said pumping elements. 
     
     
         15 . The vacuum pump according to  claim 1 , wherein said two radial bearings comprise radial gas foil bearings.