Centrifugal compressor

Abstract

A centrifugal compressor is equipped with a resin housing, that is made in a manner such that compression efficiency is not lost and merits such as weight and cost reduction are not cancelled out. The turbo charger housing comprises a volute section, a channel formation section, and an impeller that is fixed in the center of the channel formation section to a rotating shaft. An annular shroud is disposed in a recess formed on the inner wall of the channel formation section. The annular shroud forms the outer walls of a channel and a diffuser for compressed gas. The edge of the annular shroud spaced from a partition wall, which forms a portion of a bearing housing. If the resin housing undergoes thermal deformation, the dimensions of a gap between the annular shroud and the curved profile of a blade is maintained.

1 . A centrifugal compressor comprising:
 an impeller which comprises a plurality of blades fixed radially to a rotating shaft; and   a resin housing which is arranged around the impeller and which is made of resin, wherein between the impeller and the resin housing, a flow path for a gas to be compressed is formed by an outer periphery of the impeller and an inner wall of a path forming section of the resin housing, the gas flowing in the flow path from an axial direction to a radial direction of the impeller,   wherein the inner wall of the path forming section of the resin housing is carved to form a depression in which an annular shroud is provided, the annular shroud being made of one of a metal and a ceramic material and forming an outer surface of the flow path where the impeller is arranged and an outer surface of a diffuser which is arranged on an outlet side of the flow path, and   wherein the annular shroud is fixed to a wall facing the annular shroud at the diffuser.   
     
     
         2 . The centrifugal compressor according to  claim 1 , further comprising:
 a seal ring housed in a groove which is disposed between a rear face of the annular shroud and the depression of the inner wall of the path forming section.   
     
     
         3 . The centrifugal compressor according to  claim 2 , wherein the path forming section of the resin housing is separable at a separating plane into an upstream portion and a downstream portion in a direction of flow of the gas, the separating plane being positioned at the groove for housing the seal ring. 
     
     
         4 . The centrifugal compressor according to  claim 1 , wherein the resin housing has a slit in one of the path forming section and a separated part of the path forming section, the split being formed in an axial direction of the rotating shaft and opening to outside. 
     
     
         5 . The centrifugal compressor according to  claim 1 , wherein between the annular shroud and the path forming section of the resin housing, a circulation space for the gas is formed, and at least two communication openings are formed along a flow direction of the gas such that the communication space and the flow path are in communication with each other through the communication openings to allow the gas to flow in the communication space. 
     
     
         6 . The centrifugal compressor according to  claim 1 , wherein the path forming section of the resin housing is reinforced by an annular reinforcement layer covering an outer wall of the path forming section, the reinforcement layer being made of glass fiber.