Rotor assembly for an exhaust gas turbocharger

Abstract

In a rotor assembly for an exhaust gas turbocharger including a turbine wheel and a compressor wheel mounted on a common shaft for joint rotation wherein the turbine wheel consist of a metal aluminide or of a high-temperature resistant titanium alloy, the turbine wheel and the compressor wheel are disposed on the shaft in spaced relationship by way of a bearing sleeve via which the turbien wheel and the compressor wheel are axially firmly engaged by axial clamping structures associated with the common shaft.

1 . A rotor assembly for an exhaust gas turbocharger, comprising a shaft ( 4 ) rotatable about an axis of rotation ( 5 ), a turbine wheel ( 3 ) mounted on the shaft ( 11 ) for the expansion of a first gaseous medium, and a compressor wheel ( 2 ) mounted on the shaft ( 4 ) for the compression of a second gaseous medium, and the turbine wheel ( 3 ) consisting of a metal aluminide, or of a high-temperature resistant titanium alloy and being rotationally fixed with respect to the compressor wheel ( 2 ) by means of the shaft ( 4 ), and the turbine wheel ( 3 ) having an axial opening ( 6 ) at least partially extending through the turbine wheel ( 3 ) and receiving the shaft ( 4 ) with a rotationally fixed connection between the turbine wheel ( 3 ) and the shaft ( 4 ) and a sleeve ( 10 ) disposed around the shaft ( 4 ) and arranged between the turbine wheel ( 3 ) and the compressor wheel ( 2 ) in firm axial engagement with the turbine wheel ( 3 ) and the compressor wheel ( 2 ). 
   
   
       2 . The rotor assembly according to  claim 1 , wherein the shaft ( 4 ) has a first end ( 7 ) firmly engaged with the turbine wheel ( 3 ) and a second end ( 8 ) provided with tensioning means ( 9 ) for axially engaging the compressor wheel ( 2 ) with the turbine wheel ( 3 ) via the intermediate sleeve ( 10 ). 
   
   
       3 . Rotor assembly according to  claim 2 , wherein the shaft ( 4 ) extends fully through the compressor wheel ( 3 ) and the tensioning means is a nut ( 9 ) threaded onto the shaft ( 4 ) for axially engaging the turbine wheel ( 3 ) and the compressor wheel ( 2 ) via the bearing sleeve ( 10 ). 
   
   
       4 . The rotor assembly according to  claim 1 , wherein the turbine wheel ( 3 ) comprises a collar ( 13 ) at an end face ( 12 ) of the wheel ( 12 ), provided with an annular first groove ( 11 ) for receiving sealing elements. 
   
   
       5 . The rotor assembly according to  claim 4 , wherein an annular carrier ( 14 ) is disposed in the annular groove ( 11 ). 
   
   
       6 . The rotor assembly according to  claim 1 , wherein a centering collar ( 15 ) is provided at an end face ( 12 ) of the turbine wheel ( 3 ) for engaging the sleeve ( 10 ). 
   
   
       7 . The rotor assembly according to  claim 6 , wherein the centering collar ( 15 ) and the sleeve ( 10 ) are firmly connected to each another. 
   
   
       8 . The rotor assembly according to  claim 6 , wherein an air gap is provided between a first surface ( 17 ) of the centering collar ( 15 ) facing away from the end face ( 12 ) of the turbine wheel ( 3 ) and a second surface ( 18 ) of the sleeve ( 10 ) facing the end face ( 12 ) of the turbine wheel ( 3 ). 
   
   
       9 . The rotor assembly according to  claim 6 , wherein an insulation sleeve ( 20 ) is arranged in the axial opening ( 6 ) between the turbine wheel ( 3 ) and the shaft ( 4 ). 
   
   
       10 . The rotor assembly according to  claim 6 , wherein an insulating disk ( 21 ) is provided between a collar ( 13 ) of the turbine wheel ( 3 ) and the sleeve ( 10 ). 
   
   
       11 . The rotor assembly according to  claim 6 , wherein the compressor wheel ( 2 ) is provided with a bearing collar ( 25 ) which is positively connected to an end of the sleeve ( 10 ) facing the bearing collar ( 25 ) for engagement with the compressor wheel ( 2 ).