Control valve for variable displacement compressor

Abstract

To prevent the movable parts of a solenoid of a control valve for a variable displacement compressor, in which a diaphragm is used as a pressure-sensing section, from being affected by metal dust contained in refrigerant. A core, a plunger, and a spring of a solenoid are accommodated in a bottomed sleeve. A diaphragm is welded to an open end of the bottomed sleeve under a vacuum ambience, whereby an assembly that makes the inside a vacuum is formed. As a result, suction pressure Ps can be sensed as an absolute pressure with reference to a vacuum. The movable parts of the solenoid are housed in the vacuum container, so that they are free from the influence of metal dust contained in refrigerant circulating through a refrigeration cycle.

1 . A control valve for a variable displacement compressor, which is mounted on the variable displacement compressor for control of pressure in a gastightly-formed crankcase by sensing suction pressure by a diaphragm, 
 wherein a core of a solenoid and a plunger urged in a direction away from the core are accommodated in a bottomed sleeve, and an open end of the bottomed sleeve is sealed by the diaphragm such that an inside of the bottomed sleeve is kept gastight.    
   
   
       2 . The control valve according to  claim 1 , wherein the core is press-fitted in the bottomed sleeve, and a magnetic gap between the core and the plunger is adjusted by an amount of press-fitting of the core into the bottomed sleeve.  
   
   
       3 . The control valve according to  claim 2 , wherein the bottomed sleeve has a bottom-side portion thereof formed as a part for press-fitting of the core by reducing a diameter of the bottom-side portion.  
   
   
       4 . The control valve according to  claim 1 , comprising a shaft axially extending through the core and having one end thereof fixed to the plunger, a bearing disposed in contact with a bottom of the bottomed sleeve and supporting the other end of the shaft, and a spring having one end thereof engaged with the shaft and the other end thereof held in abutment with the bearing and urging the plunger in the direction away from the core, and wherein a position of the bearing receiving the spring is changed by deforming the bottom of the bottomed sleeve from outside such that the bottom is dented, to thereby adjust load of the spring.  
   
   
       5 . The control valve according to  claim 1 , wherein the bottomed sleeve has a flange portion formed on an open end thereof, the diaphragm being circumferentially welded to the flange portion along an entire perimeter thereof to seal the bottomed sleeve, and a sealing member for sealing between a space from which the diaphragm receives the suction pressure and the atmosphere is disposed radially inward of a position where the diaphragm is welded.  
   
   
       6 . The control valve according to  claim 1 , wherein the diaphragm comprises a base part formed with a hole in a central portion thereof and welded to a flange portion formed on the open end of the bottomed sleeve, a funnel-shaped intermediate connecting part having an inner periphery welded to an inner periphery of the base part, and a disk having an outer periphery welded to an outer periphery of the intermediate connecting part.