Displacement control valve of clutchless variable displacement inclined plate-type compressor

Abstract

A displacement control valve of a clutchless variable displacement inclined plate-type compressor for controlling the discharge displacement of the compressor by opening and closing a communication path between a discharge chamber and a crank chamber. The displacement control valve has a valve hole ( 106 ) formed in the communication path and always communicating with the discharge chamber, an inside control valve ( 100 ) for opening and closing the valve hole ( 106 ) by a valve body ( 112 ) operated in response to expansion and contraction of a pressure sensing member ( 109 ) for sensing a suction pressure, and an operation switching device ( 120 ) connected to the inside control valve for switching the inside control valve between an operating condition where the valve body opens and closes the valve hole in response to the expansion and contraction of the pressure sensing member and a non-operating condition where the valve body opens the valve hole independently of the expansion and contraction of the pressure sensing member. In this displacement control valve, because a discharge pressure Pd acts on both the valve body ( 112 ) and a pressure sensing rod ( 110 ), the force of the discharge pressure Pd for urging the valve body ( 112 ) in a valve opening direction is (Sr−Sv)Pd. The displacement control valve can be made smaller than conventional displacement control valves because (Sr−Sv) is very small.

1 . A displacement control valve of a clutchless variable displacement inclined plate-type compressor for controlling a discharge displacement of said compressor by opening and closing a communication path between a discharge chamber and a crank chamber of said compressor, said displacement control valve comprising: 
 a valve hole formed in said communication path and communicating with said discharge chamber;    an inside control valve for opening and closing said valve hole by a valve body operated in response to expansion and contraction of a pressure sensing member for sensing a suction pressure; and    an operation switching device connected to said inside control valve for switching said inside control valve between an operating condition where said valve body opens and closes said valve hole in response to said expansion and contraction of said pressure sensing member and a non-operating condition where said valve body opens said valve hole independently of said expansion and contraction of said pressure sensing member.    
   
   
       2 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 1 , wherein said operation switching device has an electromagnetic solenoid, when said electromagnetic solenoid is excited, said inside control valve switches to said operating condition, and when said electromagnetic solenoid is degaussed, said inside control valve switches to said non-operating condition.  
   
   
       3 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 2 , wherein said electromagnetic solenoid includes a movable core connected to said inside control valve and a positioning member for positioning said inside control valve at an operating position when said electromagnetic solenoid is excited.  
   
   
       4 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 3 , wherein said positioning member is formed by one end of said pressure sensing member and an end surface of a case of said electromagnetic solenoid.  
   
   
       5 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 2 , wherein said electromagnetic solenoid includes a releasing spring for urging a movable core in a direction apart from a fixed core, and when said electromagnetic solenoid is degaussed, said inside control valve switches to said non-operating condition by said releasing spring.  
   
   
       6 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 1 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       7 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 1 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.  
   
   
       8 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 3 , wherein said electromagnetic solenoid includes a releasing spring for urging a movable core in a direction apart from a fixed core, and when said electromagnetic solenoid is degaussed, said inside control valve switches to said non-operating condition by said releasing spring.  
   
   
       9 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 4 , wherein said electromagnetic solenoid includes a releasing spring for urging a movable core in a direction apart from a fixed core, and when said electromagnetic solenoid is degaussed, said inside control valve switches to said non-operating condition by said releasing spring.  
   
   
       10 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 2 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       11 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 3 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       12 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 4 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       13 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 5 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       14 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 8 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       15 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 9 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is greater than a cross-sectional area of said valve hole.  
   
   
       16 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 2 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.  
   
   
       17 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 3 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.  
   
   
       18 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 4 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.  
   
   
       19 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 5 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.  
   
   
       20 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 8 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.  
   
   
       21 . The displacement control valve of a clutchless variable displacement inclined plate-type compressor according to  claim 9 , wherein said inside control valve includes a pressure sensing rod which is slidably inserted into a hole formed in a valve housing and communicating with said valve hole and which is connected to said valve body, and a cross-sectional area of said pressure sensing rod is smaller than a cross-sectional area of said valve hole.