Compressor having a suction throttle valve

Abstract

A compressor has a compression chamber formed in a cylinder block, a suction passage formed upstream of the compression chamber and a suction throttle valve formed in the suction passage for adjusting opening of the suction passage. The suction throttle valve has a valve hole and a valve seat formed around the valve hole, a valve body for opening and closing the valve hole and an urging member for urging the valve body in the direction which causes the valve hole to be closed. The urging member is a disk spring. The spring characteristics of the disk spring includes a range where the increasing rate of the load required for displacement of the disk spring is reduced with an increase of displacement of the disk spring. The displacement range of the valve body includes a range where the increasing rate of the load of the disk spring is reduced with an increase of the displacement of the disk spring.

1 . A compressor comprising: 
 a compression chamber formed in a cylinder block;    a suction passage formed upstream of the compression chamber; and    a suction throttle valve formed in the suction passage for adjusting opening of the suction passage,    wherein the suction throttle valve has a valve hole and a valve seat formed around the valve hole, a valve body for opening and closing the valve hole and an urging member for urging the valve body in the direction which causes the valve hole to be closed,    wherein the urging member is a disk spring,    wherein the spring characteristics of the disk spring includes a range where the increasing rate of the load required for displacement of the disk spring is reduced with an increase of displacement of the disk spring, and    wherein the displacement range of the valve body includes a range where the increasing rate of the load of the disk spring is reduced with an increase of the displacement of the disk spring.    
   
   
       2 . The compressor according to  claim 1 , wherein the urging member is a plurality of disk springs arranged in series in the direction in which the disk springs are displaced.  
   
   
       3 . The compressor according to  claim 1 , the total displacement of the disk spring is set 1.4 times or greater as large as the thickness of the disk spring.  
   
   
       4 . The compressor according to  claim 1 , wherein where the valve hole is kept closed by the valve body, the initial urging force of the disk spring is set in such a way that the load of the disk spring is decreased with an increase of the displacement of the disk spring due to the displacement of the valve body.  
   
   
       5 . The compressor according to  claim 1 , wherein the valve body has a guide rod extending downwardly from the bottom thereof and the guide rod is inserted through a rod hole of the disk spring.  
   
   
       6 . The compressor according to the  claim 1 , wherein a communication passage is formed through the valve body, and upstream and downstream of the suction throttle valve in the communication passage is in communication with each other through the communication passage when the valve hole is closed.