Piston type variable displacement compressor

Abstract

In the piston type variable displacement compressor of the present invention, in the crank chamber 5 in which the crank mechanism is arranged, the outlet 28 A of the gas supply passage 28 , for supplying refrigerant from the discharge chamber 22 , is open at an upper position of the crank mechanism in the peripheral wall section of the housing. The control valve 29 is arranged in the middle of the gas supply passage 28 , so that a flow rate of the refrigerant supplied into the crank chamber 5 via the gas supply passage 28 can be adjusted. Mist-like lubricant is mixed with the refrigerant. Therefore, even when the flow rate of the refrigerant is low, the crank chamber 5 can be excellently lubricated.

1 . A piston type variable displacement compressor comprising: 
 a crank chamber defined in a housing; and    a crank mechanism, arranged in the crank chamber, for transforming a rotational motion of a drive shaft into a reciprocating motion of a piston which sucks, compresses and discharges refrigerant and also for changing a stroke of the piston according to inner pressure in the crank chamber, wherein    an outlet of a gas supply passage for supplying the refrigerant from a high pressure region into the crank chamber is open at an upper position of the crank mechanism in the crank chamber.    
     
     
         2 . A piston type variable displacement compressor according to    claim 1   , wherein a control valve for controlling a quantity of the refrigerant supplied from the gas supply passage into the crank chamber is arranged in the gas supply passage.  
     
     
         3 . A piston type variable displacement compressor according to    claim 1   , wherein the piston type variable displacement compressor is of the type in which a swash plate and the drive shaft are integrated and rotated with each other.  
     
     
         4 . A piston type variable displacement compressor according to    claim 1   , wherein the piston type variable displacement compressor is of the type in which a swash plate and the drive shaft are rotated, but not integrated, with each other.  
     
     
         5 . A piston type variable displacement compressor according to    claim 1   , wherein the outlet is formed toward a thrust bearing for supporting the crank mechanism in the direction of the drive shaft and/or a hinge mechanism for changing the stroke of the piston.  
     
     
         6 . A piston type variable displacement compressor according to    claim 1   , wherein a gas extraction passage for introducing the refrigerant from the crank chamber into a low pressure region is provided, and a control valve for controlling a quantity of the refrigerant introduced from the crank chamber into the low pressure region is arranged in the gas extraction passage.