Capacity control valve for variable displacement compressor

Abstract

To provide a capacity control valve for a variable displacement compressor, which is capable of returning lubricating oil contained in refrigerant into a crank chamber efficiently by a simple construction. A valve element is disposed in a refrigerant passage communicating between a discharge chamber and a crank chamber in a variable displacement compressor, such that the valve element can be seated from a crank chamber side, and opens and closes the refrigerant passage. A valve seat-forming member is so formed as to contain a valve seat and a valve hole on which the valve element is seated, and a through hole as a communication passage communicating between a discharge chamber side and the crank chamber side. When a solenoid section is energized, and the valve element is urged by a piston rod to close the valve, refrigerant from the discharge chamber side flows into the crank chamber side through the through hole. Thus, even when the valve element is seated, lubricating oil can be circulated within the variable displacement compressor.

What is claimed is:  
     
         1 . A capacity control valve for a variable displacement compressor, for controlling an amount of refrigerant to be introduced from a discharge chamber into a crank chamber, to thereby change an capacity of refrigerant discharged from the variable displacement compressor, 
 characterized in that a communication passage is formed in a valve seat-forming member disposed in a refrigerant passage communicating between the discharge chamber and the crank chamber for constantly communicating between a discharge chamber side and a crank chamber side.    
     
     
         2 . The capacity control valve for a variable displacement compressor according to  claim 1 , wherein the communication passage is a through hole formed through the valve seat-forming member in parallel with a valve hole.  
     
     
         3 . The capacity control valve for a variable displacement compressor according to  claim 1 , wherein the communication passage is a nick formed on one portion of a valve seat such that a gap is formed when the valve is closed.  
     
     
         4 . The capacity control valve for a variable displacement compressor according to  claim 1 , further comprising a holding member having a press-fitting opening communicating between the discharge chamber side and the crank chamber side, and holding the valve seat-forming member press-fitted in the press-fitting opening, and 
 wherein the communication passage is a groove formed on an outer peripheral surface of the valve seat-forming member in a manner extending from the discharge chamber side to the crank chamber side.    
     
     
         5 . The capacity control valve for a variable displacement compressor according to  claim 1 , further comprising a valve element disposed for opening and closing the refrigerant passage, such that the valve element can be seated on a valve seat formed on the valve seat-forming member, from the crank chamber side, and 
 a solenoid section for applying a solenoid force to the valve element in an axial direction of the valve element.    
     
     
         6 . The capacity control valve for a variable displacement compressor according to  claim 5 , further comprising a piston rod disposed coaxially with the valve element, and having one end adjacent to the valve element and the other end having a pressure-receiving area as large as an effective pressure-receiving area of the valve element, the piston rod receiving suction pressure from a suction chamber on the other end thereof.