Turbomolecular pump

Abstract

A turbomolecular pump has a rotor element in a housing. The rotor element is arranged on a rotor shaft. The rotor shaft is supported by two bearing elements in the housing. The bearing element on the high-vacuum side is constructed as a roller bearing. In order to guarantee a pressure in the area of the bearing element that is acceptable for the bearing element constructed as a roller bearing, the bearing element is arranged in a chamber. The chamber is connected via a channel to the pre-vacuum area and sealed relative to the high-vacuum area by a gasket.

What is claimed is: 
     
         1 . A turbomolecular pump comprising
 at least one rotor element with a plurality of rotor blades, said element being supported in a housing by means of a rotor element,   at least one stator element comprising a plurality of stator blades projecting between the rotor blades, and   at least two bearing elements arranged in end areas of the rotor shaft, wherein at least the bearing element on the high-vacuum side is formed as a roller bearing and is arranged in a chamber that is connected via at least one channel to a pressure area in which a higher pressure prevails than in the high-vacuum area.   
     
     
         2 . The turbomolecular pump according to  claim 1 , wherein in the pressure area, in which a higher pressure prevails, the pressure prevailing is at least 1·10 −5  mbar, in particular 1·10 −3  mbar. 
     
     
         3 . The turbomolecular pump as defined according to  claim 1 , wherein in the high-vacuum area a pressure prevails that is lower than 1·10 −3  mbar, in particular lower than 1·10 −5  mbar, and particularly preferred lower than 1·10 −7  mbar. 
     
     
         4 . The turbomolecular pump according to  claim 1 , wherein the chamber is at least partly formed by a bearing receiving element connected directly or indirectly with the housing. 
     
     
         5 . The turbomolecular pump according to  claim 1 , wherein the chamber is closed on the high-vacuum side with a cover preferably connected with the bearing receiving element. 
     
     
         6 . The turbomolecular pump according to  claim 4 , wherein the bearing receiving element is connected with the housing through a support element which is in particular star-shaped. 
     
     
         7 . The turbomolecular pump according to  claim 4 , further comprising a gasket element arranged between the bearing receiving element and the rotor element. 
     
     
         8 . The turbomolecular pump efaccording to  claim 7 , wherein the gasket element is arranged in an annular gap formed by the bearing receiving element and the rotor element. 
     
     
         9 . The turbomolecular pump according to  claim 7 , wherein the gasket element comprises a labyrinth seal. 
     
     
         10 . The turbomolecular pump according to  claim 7 , further comprising a sealing gap of the gasket element has a cross-sectional area smaller than the cross-sectional area of the channel or the sum of the cross-sectional areas of a plurality of channels. 
     
     
         11 . The turbomolecular pump according to  claim 7 , wherein the gasket element comprises an active sealing element, the active sealing element in particular comprising the Holweck stage or being designed as a Holweck stage. 
     
     
         12 . The turbomolecular pump according to  claim 1 , wherein the at least one channel is connected with the pre-vacuum area.