Variable displacement compressor

Abstract

A variable displacement compressor for forming a refrigerant circuit with an external refrigerant circuit includes a housing, a drive shaft, a swash plate, a shaft seal member, a supply passage, a control valve and a gas passage. The housing has a suction chamber, a crank chamber, a discharge chamber and a shaft seal chamber formed therein. The discharge chamber is in communication with the crank chamber through the supply passage. The supply passage has the shaft seal chamber. The discharge chamber is in communication with the external refrigerant circuit through the gas passage. The supply passage is formed differently from the gas passage. A part of the supply passage is located adjacent to the suction chamber and nearer to the suction chamber than the discharge chamber.

1 . A variable displacement compressor for forming a refrigerant circuit with an external refrigerant circuit, comprising: 
 a housing having a suction chamber, a crank chamber, a discharge chamber and a shaft seal chamber formed therein;    a drive shaft rotataby supported by the housing;    a swash plate connected to the drive shaft so that angle of inclination of the swash plate relative to the drive shaft is variable, the swash plate being accommodated in the crank chamber;    a shaft seal member accommodated in the shaft seal chamber;    a supply passage through which the discharge chamber is in communication with the crank chamber, the supply passage including the shaft seal chamber;    a control valve disposed in the supply passage, flow rate of refrigerant gas supplied from the discharge chamber to the crank chamber through the supply passage being adjusted by adjusting an opening degree of the control valve; and    a gas passage through which the discharge chamber is in communication with the external refrigerant circuit;    wherein the supply passage is formed differently from the gas passage, a part of the supply passage being located adjacent to the suction chamber and nearer to the suction chamber than the discharge chamber.    
   
   
       2 . The variable displacement compressor according to  claim 1 , wherein the suction chamber is formed radially outward of the discharge chamber, the part of the supply passage being located radially outward of a partition wall which separates the discharge chamber and the suction chamber.  
   
   
       3 . The variable displacement compressor according to  claim 2 , wherein the part of the supply passage is located radially outward of the suction chamber.  
   
   
       4 . The variable displacement compressor according to  claim 2 , wherein the part of the supply passage is located so as to traverse the suction chamber.  
   
   
       5 . The variable displacement compressor according to  claim 1 , wherein the suction chamber is formed radially inward of the discharge chamber, the part of the supply passage being located radially inward of a partition wall which separates the discharge chamber and the suction chamber.  
   
   
       6 . The variable displacement compressor according to  claim 5 , wherein the part of the supply passage is located so as to traverse the suction chamber.  
   
   
       7 . The variable displacement compressor according to  claim 1 , wherein the suction chamber is formed radially outward of the discharge chamber, the part of the supply passage being located in an outer wall surface of a partition wall which separates the discharge chamber and the suction chamber.  
   
   
       8 . The variable displacement compressor according to  claim 1 , wherein the suction chamber is formed radially inward of the discharge chamber, the part of the supply passage being located in an inner wall surface of a partition wall which separates the discharge chamber and the suction chamber.  
   
   
       9 . The variable displacement compressor according to  claim 1 , wherein the part of the supply passage is located downstream from the control valve in the supply passage.  
   
   
       10 . The variable displacement compressor according to  claim 1 , wherein another part of the supply passage is formed in the drive shaft.  
   
   
       11 . The variable displacement compressor according to  claim 1 , wherein a bleed passage through which the refrigerant gas in the crank chamber is drawn to the suction chamber is disposed in the housing, and wherein at least parts of the supply passage and the bleed passage are formed in the drive shaft, the part of the supply passage which is formed in the drive shaft being in communication with the shaft seal chamber, the part of the bleed passage which is formed in the drive shaft being formed between the part of the supply passage in the drive shaft and an outer circumferential surface of the drive shaft.  
   
   
       12 . The variable displacement compressor according to  claim 11 , wherein the drive shaft includes a cylindrical hollow first shaft portion and a cylindrical hollow second shaft portion inserted in the first shaft portion, the part of the bleed passage formed in the drive shaft being defined by an inner circumferential surface of the first shaft portion and an outer circumferential surface of the second shaft portion, the part of the supply passage formed in the drive shaft being defined by an inner circumferential surface of the second shaft portion.  
   
   
       13 . The variable displacement compressor according to  claim 12 , wherein an accommodation space is defined in the housing for accommodating a rear end of the drive shaft therein, parts of the supply passage and the bleed passage being defined in the accommodation space by a seal member disposed on the second shaft portion.  
   
   
       14 . The variable displacement compressor according to  claim 13 , wherein the part of the supply passage is in communication with the accommodation space through a valve plate assembly.  
   
   
       15 . The variable displacement compressor according to  claim 1 , wherein the supply passage and the gas passage are partially shared and then are separated from each other.  
   
   
       16 . The variable displacement compressor according to  claim 1 , wherein the supply passage and the gas passage are separately formed.