Turbomolecular pump

Abstract

A turbomolecular pump ( 10 ) includes a rotor ( 18 ) which is mounted on a housing ( 12 ) by at least one roller bearing ( 16 ). The roller bearing ( 16 ) comprises a non-rotating bearing shell ( 20 ) and a rotating bearing shell ( 22 ). The non-rotating bearing shell ( 20 ) is mounted on the housing ( 12 ) by an elastic vibration ring ( 14 ). The vibration ring ( 14 ) is of an anisotropic form, such that the spring stiffness is inhomogeneous over the circumference.

1 . A turbomolecular pump comprising a rotor supported on a housing by means of a roller bearing,
 said roller bearing comprising a non-rotating bearing shell and a rotating bearing shell, and   said non-rotating bearing shell being supported on the housing by an elastic vibration ring, wherein   said vibration ring is of an anisotropic form such that its spring stiffness is inhomogeneous over its circumference.   
     
     
         2 . The turbomolecular pump according to  claim 1 , wherein the vibration ring is one-pieced and its form is anisotropic along the circumference. 
     
     
         3 . The turbomolecular pump according to  claim 1 , wherein the vibration ring comprises a plurality of support sites distributed in a non-uniform manner along the circumference. 
     
     
         4 . The turbomolecular pump according to  claim 3 , wherein the distance from one of the support sites to a first neighboring support site towards one side is unequal to the distance to a second neighboring support site on the other side. 
     
     
         5 . The turbomolecular pump according to  claim 1 , wherein the vibration ring is formed by a one-pieced elastic body which on the housing side is continuously closed and on the bearing side is interrupted by axial grooves separating the support sites from each other. 
     
     
         6 . The turbomolecular pump according to  claim 1 , wherein the vibration ring is made of different materials distributed along the circumference. 
     
     
         7 . The turbomolecular pump according to  claim 1 , wherein the vibration ring includes a helical coil made of a uniform spring wire. 
     
     
         8 . A turbomolecular pump comprising:
 a housing;   a roller bearing which supports a rotor in the housing, the roller bearing including a non-rotating bearing race and a rotating bearing race; and   an elastic ring supporting the non-rotating bearing race in the housing, the elastic ring having anisotropic vibration damping properties with an inhomogeneous spring stiffness over its circumference.