Centrifugal compressor with scroll flow path

Abstract

An example centrifugal compressor includes a rotary shaft, a compressor impeller fixed to the rotary shaft; and a flow path wall forming a scroll flow path around the compressor impeller. The flow path wall includes an outer peripheral wall located on an outer side of the scroll flow path in a radial direction of the rotary shaft; and an inner peripheral wall located on an inner side of the scroll flow path closer to the rotary shaft than the outer peripheral wall in the radial direction. The outer peripheral wall includes a thickened portion having a wall thickness greater than a wall thickness of a portion of the inner peripheral wall that is opposite the thickened portion in the radial direction.

What is claimed is: 
     
         1 . A centrifugal compressor comprising:
 a rotary shaft;   a compressor impeller fixed to the rotary shaft; and   a flow path wall forming a scroll flow path around the compressor impeller,   wherein the flow path wall includes:
 an outer peripheral wall located on an outer side of the scroll flow path in a radial direction of the rotary shaft; and 
 an inner peripheral wall located on an inner side of the scroll flow path closer to the rotary shaft than the outer peripheral wall in the radial direction, and 
   wherein the outer peripheral wall includes a thickened portion having a wall thickness greater than a wall thickness of a portion of the inner peripheral wall that is opposite the thickened portion in the radial direction.   
     
     
         2 . The centrifugal compressor according to  claim 1 ,
 wherein the flow path wall further includes a connecting wall portion connecting the outer peripheral wall to the inner peripheral wall, and   wherein the connecting wall portion includes a transition portion whose thickness changes continuously from the thickened portion to the inner peripheral wall.   
     
     
         3 . The centrifugal compressor according to  claim 1 , further comprising a discharge pipe forming a discharge flow path fluidly coupled with the scroll flow path,
 wherein the thickened portion is located opposite to the discharge pipe with respect to the rotary shaft.   
     
     
         4 . The centrifugal compressor according to  claim 1 , further comprising a discharge pipe forming a discharge flow path fluidly coupled with the scroll flow path and having a pipe axis extending in a tangential direction of the scroll flow path,
 wherein the flow path wall includes, in a cross-section along a plane that includes a rotation axis of the compressor impeller and is parallel to the pipe axis, a first flow path wall portion located upstream in a flow direction of the scroll flow path, and a second flow path wall portion located downstream in the flow direction, and   wherein the thickened portion is located in a flow path region from the first flow path wall portion to the second flow path wall portion in the flow direction of the scroll flow path.   
     
     
         5 . The centrifugal compressor according to  claim 4 , wherein the thickened portion is provided over the entire flow path region. 
     
     
         6 . The centrifugal compressor according to  claim 5 , wherein a ratio of the wall thickness of the thickened portion to the wall thickness of the inner peripheral wall opposing the thickened portion in the radial direction in the flow path region is constant. 
     
     
         7 . The centrifugal compressor according to  claim 1 , further comprising:
 a compressor housing that houses the compressor impeller and includes the flow path wall; and   a diffuser plate fixed to the compressor housing to form a diffuser flow path, wherein   a thickness of the diffuser plate is thinner than the wall thickness of the thickened portion.   
     
     
         8 . The centrifugal compressor according to  claim 7 , wherein the thickness of the diffuser plate is greater than the wall thickness of the portion of the inner peripheral wall. 
     
     
         9 . The centrifugal compressor according to  claim 1 , further comprising:
 a compressor housing that houses the compressor impeller and includes the flow path wall; and   a diffuser plate fixed to the compressor housing to form a diffuser flow path,   wherein the flow path wall connects the outer peripheral wall to the inner peripheral wall and includes a connecting wall portion located to face the diffuser plate.   
     
     
         10 . The centrifugal compressor according to  claim 9 , wherein the connecting wall portion includes a thin-walled portion thinner than the diffuser plate. 
     
     
         11 . The centrifugal compressor according to  claim 1 , further comprising a compressor housing that houses the compressor impeller,
 wherein the compressor housing includes a scroll portion including the flow path wall, and a discharge pipe connected to the scroll portion to form a discharge flow path communicating with the scroll flow path, and   wherein the outer peripheral wall includes the thickened portion over an entire region along the scroll flow path.   
     
     
         12 . The centrifugal compressor according to  claim 1 , wherein the scroll flow path surrounds more than half of a circumference of the compressor impeller. 
     
     
         13 . A centrifugal compressor comprising:
 a compressor impeller;   a scroll flow path located around the compressor impeller;   an outer peripheral wall facing the scroll flow path; and   an inner peripheral wall facing the scroll flow path and located between the compressor impeller and the outer peripheral wall,   wherein the outer peripheral wall includes a thickened portion facing a portion of the inner peripheral wall in a radial direction of the compressor impeller, the thickened portion has a wall thickness greater than a wall thickness of the portion of the inner peripheral wall.   
     
     
         14 . The centrifugal compressor according to  claim 13 ,
 wherein the outer peripheral wall extends along the scroll flow path,   wherein the inner peripheral wall extends along the scroll flow path, and   wherein a wall thickness of the outer peripheral wall is greater than a wall thickness of the inner peripheral wall in an entire region along the scroll flow path.   
     
     
         15 . The centrifugal compressor according to  claim 14 , wherein a ratio of the wall thickness of the outer peripheral wall to the wall thickness of the inner peripheral wall in the entire region along the scroll flow path is constant. 
     
     
         16 . The centrifugal compressor according to  claim 13 , further comprises a connecting wall connecting the thickened portion and the portion of the inner peripheral wall, the connecting wall including a transition portion whose thickness changes continuously from the thickened portion to the portion of the inner peripheral wall. 
     
     
         17 . A centrifugal compressor comprising:
 a compressor impeller;   a scroll flow path located around the compressor impeller;   an outer peripheral wall facing the scroll flow path;   an inner peripheral wall facing the scroll flow path and located between the compressor impeller and the outer peripheral wall; and   a connecting wall connecting the outer peripheral wall and the inner peripheral wall, the connecting wall including a transition portion whose thickness changes continuously from the outer peripheral wall to the inner peripheral wall.   
     
     
         18 . The centrifugal compressor according to  claim 17 , wherein the scroll flow path partially surrounds a circumference of the compressor impeller. 
     
     
         19 . The centrifugal compressor according to  claim 17 , wherein a wall thickness of the outer peripheral wall is greater than a wall thickness of the inner peripheral wall. 
     
     
         20 . The centrifugal compressor according to  claim 17 , wherein a ratio of a thickness of the outer peripheral wall to a thickness of the inner peripheral wall opposing the outer peripheral wall in a radial direction of the compressor impeller is constant.