Turbocharger

Abstract

A sealing structure includes a labyrinth seal provided between a housing and an outer periphery of an end portion of a turbine shaft on a turbine wheel side, and a piston ring seal disposed on a side toward a center of the turbine shaft in an axial direction thereof from a position on the turbine shaft at which the labyrinth seal is provided, and a ring groove is formed along a circumferential direction of the housing in a middle portion of the labyrinth seal to reverse a flow direction of exhaust gas entering from the exhaust passage.

1 . A turbocharger comprising:
 a turbine shaft;   a turbine wheel disposed on a first end portion of the turbine shaft in an exhaust passage of an internal combustion engine;   a compressor wheel disposed on a second end portion of the turbine shaft in an admission passage of the internal combustion engine;   a rolling bearing rotatably supporting the turbine shaft within a shaft hole of a housing; and   a sealing structure performing a sealing between the shaft hole and the exhaust passage,   wherein the sealing structure includes a labyrinth seal provided between an outer periphery of the first end portion of the turbine shaft and the housing, and a piston ring seal disposed on a side toward a center of the turbine shaft in an axial direction thereof from a position on the turbine shaft at which the labyrinth seal is provided, and   wherein a ring groove is formed along a circumferential direction of the housing in a middle portion of the labyrinth seal to reverse a flow direction of exhaust gas entering from the exhaust passage.   
   
   
       2 . A turbocharger according to  claim 1 , wherein a coolant water jacket in which coolant water for cooling the turbine shaft is circulated is provided on a radial outer side of the turbine shaft from the position of the housing at which the labyrinth seal is provided.