Variable geometry turbocharger

Abstract

An exhaust nozzle 9 has nozzle vanes 15 interposed between front and rear exhaust introduction walls 10 and 51. A space 19 is between the wall 51 and a turbine housing 1. A sealing device 25 is arranged upstream, in a direction of exhaust gas, of each through hole 24 provided in the wall 51 for penetration of a vane shaft 16 a to prevent exhaust gas in a scroll passage 8 from leaking through the space 19 to a turbine impeller 4. Each of the walls 10 and 51 is disk-shaped, the turbine housing 1 being formed with a shoulder 50 to which the wall 51 is fitted with the space 19.

1 . A variable geometry turbocharger with an exhaust nozzle having nozzle vanes interposed between front and rear exhaust introduction walls, a space being between said rear exhaust introduction wall and a turbine housing, a sealing device being arranged upstream, in a direction of exhaust gas, of each through hole provided in said rear exhaust introduction wall for penetration of a vane shaft to prevent exhaust gas in a scroll passage from leaking through said space to a turbine impeller, wherein each of said front and rear exhaust introduction walls is disk-shaped, said turbine housing being formed with a shoulder to which the disk-shaped rear exhaust introduction wall is fitted with said space. 
     
     
         2 . The variable geometry turbocharger as claimed in  claim 1 , wherein said front and rear exhaust introduction walls are equivalent in linear expansion coefficient. 
     
     
         3 . The variable geometry turbocharger as claimed in  claim 1 , wherein said sealing device comprises sealing piston rings. 
     
     
         4 . The variable geometry turbocharger as claimed in  claim 1 , wherein said sealing device comprises a disk spring seal.