Swash plate type compressor

Abstract

A shaft and a rotary valve, which are formed integrally, are made of an iron-based metal while a cylinder block is made of an aluminum-based metal. A sleeve forms a slide surface between the cylinder block and the rotary valve when the shaft and the rotary valve rotate together. The sleeve has a coefficient of thermal expansion closer to those of the shaft and the rotary valve than that of the cylinder block. This structure prevents an increase in the clearance between the housing and the rotary valve due to the increased temperature at the time the shaft rotates at a high speed, and prevents gas leakage and a reduction in sealability.

What is claimed is:  
     
         1 . A swash plate type compressor including a housing having a cylinder block, the cylinder block having a plurality of cylinder bores around a shaft, the shaft being rotatably supported in the housing, an suction pressure area being formed in the housing, wherein a plurality of pistons are respectively inserted into the cylinder bores and reciprocate in the respective cylinder bores via a swash plate in accordance with rotation of the shaft to thereby perform a suction stroke for taking a refrigerant gas in the suction pressure area into a compression chamber formed in each cylinder bore, the swash plate type compressor comprising: 
 communication passages formed in the cylinder block in such a way as to communicate with the cylinder bores, respectively;    a rotary valve formed integral with the shaft, wherein the rotary valve has a suction passage for connecting the communication passage of each cylinder bore in the suction stroke to the suction pressure area; and    a sleeve provided on the rotary valve in the cylinder block, wherein the sleeve has a coefficient of thermal expansion closer to that of the shaft than that of the cylinder block.    
     
     
         2 . The swash plate type compressor according to  claim 1 , wherein the sleeve forms a slide surface to the rotary valve.  
     
     
         3 . The swash plate type compressor according to  claim 1 , wherein the shaft and the rotary valve are made of an iron-based metal and the cylinder block is made of an aluminum-based metal.  
     
     
         4 . The swash plate type compressor according to  claim 1 , wherein the sleeve is made of an iron-based metal.  
     
     
         5 . The swash plate type compressor according to  claim 4 , wherein the coefficient of thermal expansion of the sleeve ranges about 7 to 15×10 −6 /° C.  
     
     
         6 . The swash plate type compressor according to  claim 1 , wherein the sleeve is made of a resin or ceramics.  
     
     
         7 . The swash plate type compressor according to  claim 1 , wherein the shaft, the rotary valve and the sleeve are made of an iron-based metal.  
     
     
         8 . The swash plate type compressor according to  claim 7 , wherein the coefficient of thermal expansion of the sleeve ranges about 7 to 15×10 −6 /° C.  
     
     
         9 . The swash plate type compressor according to  claim 1 , wherein the sleeve is cast or press-fitted in the cylinder block.  
     
     
         10 . A swash plate type compressor including a housing having a cylinder block, the cylinder block having a plurality of cylinder bores around a shaft, the shaft is rotatably supported in the housing having a suction chamber and a discharge chamber, and wherein a plurality of pistons are respectively inserted into the cylinder bores and reciprocate in the respective cylinder bores via a swash plate in accordance with rotation of the shaft to thereby perform a suction stroke for taking a refrigerant gas in the suction chamber into a compression chamber formed in each cylinder bore, a compression stroke for compressing the refrigerant gas and a discharge stroke for discharging the refrigerant gas, sucked into the compression chamber, into the discharge chamber, the swash plate type compressor comprising: 
 communication passages formed in the cylinder block in such a way as to communicate with the cylinder bores, respectively;    a rotary valve formed integral with the shaft, wherein the rotary valve has a suction passage for connecting the communication passage of each cylinder bore in the suction stroke to the suction chamber; and    a sleeve provided on the rotary valve in the cylinder block, wherein the sleeve has a coefficient of thermal expansion closer to that of the shaft than that of the cylinder block.    
     
     
         11 . The swash plate type compressor according to  claim 10 , wherein the sleeve forms a slide surface to the rotary valve.  
     
     
         12 . The swash plate type compressor according to  claim 10 , wherein the shaft and the rotary valve are made of an iron-based metal and the cylinder block is made of an aluminum-based metal.  
     
     
         13 . The swash plate type compressor according to  claim 10 , wherein the sleeve is made of an iron-based metal.  
     
     
         14 . The swash plate type compressor according to  claim 13 , wherein the coefficient of thermal expansion of the sleeve ranges about 7 to 15×10 −6 /° C.  
     
     
         15 . The swash plate type compressor according to  claim 10 , wherein the sleeve is made of a resin or ceramics.  
     
     
         16 . The swash plate type compressor according to  claim 10 , wherein the shaft, the rotary valve and the sleeve are made of an iron-based metal.  
     
     
         17 . The swash plate type compressor according to  claim 16 , wherein the coefficient of thermal expansion of the sleeve ranges about 7 to 15×10 −6 /° C.  
     
     
         18 . The swash plate type compressor according to  claim 10 , wherein the sleeve is cast or press-fitted in the cylinder block.