Control valve for variable capacity compressors

Abstract

There is provided a control valve for a variable capacity compressor, which is applicable to a compressor of large capacity. This control valve comprises a valve main body ( 20 ) equipped with a valve rod ( 15 ) having a valve body ( 15 a ), with a valve chamber ( 21 ) having a guide hole ( 19 ) in which the valve rod is enabled to slide and a valve aperture ( 22 ) for the valve body, with a cooling medium inlet port ( 25 ) disposed on an upstream side of the valve aperture for introducing a cooling medium from the compressor, and with a cooling medium outlet port ( 26 ) disposed on a downstream side of the valve aperture and communicated with a crank chamber; an electromagnetic actuator ( 30 ) for driving the valve rod to move in the direction of opening or closing the valve aperture; and a pressure sensitive moving member ( 40 ) for driving the valve rod to move in response to a sucking pressure of the compressor; which is characterized in that a contracted hole portion is formed at an upper portion of the guide hole, that a diametrally reduced rod portion ( 15 b ) to be inserted into the contracted hole portion ( 19 b ) is formed at an upper portion of the valve rod, and that the valve rod is provided with an equalizing hole ( 51 ) for introducing a cooling medium pressure of the cooling medium outlet port into an equalizing pressure introducing chamber ( 52 ).

1 . A control valve for a variable capacity compressor, comprising: 
 a valve main body including 
 a valve rod having a valve body, the valve rod having a diametrally reduced rod portion formed at a first portion thereof and a diametrally enlarged rod portion formed at a second portion thereof,  
 a valve chamber having a guide hole for receiving the valve rod and a valve aperture with which the valve body is capable of being contacted, the guide hole having a contracted hole portion formed at a first portion thereof and an enlarged hole portion formed at a second portion thereof,  
 a cooling medium inlet port disposed on an upstream side of the valve aperture for introducing a cooling medium of discharge pressure from the compressor, and  
 a cooling medium outlet port disposed on a downstream side of the valve aperture and capable of communicating with a crank chamber of the compressor;  
   an electromagnetic actuator for moving the valve rod in a direction of opening or closing the valve aperture; and    a pressure sensitive moving member for moving the valve rod in the direction of opening or closing the valve aperture in response to a sucking pressure of the compressor;    wherein the diametrally reduced rod portion is adapted to be slidingly inserted into the contracted hole portion, and the valve rod includes an equalizing hole for introducing a cooling medium pressure of the cooling medium outlet port into an equalizing pressure introducing chamber within the valve main body.    
   
   
       2 . A control valve for a variable capacity compressor, which comprises: 
 a valve main body including 
 a valve rod having a valve body, the valve rod having a diametrally reduced rod portion formed at a first portion thereof and a diametrally enlarged rod portion formed at a second portion thereof,  
 a valve chamber having a guide hole for receiving the valve rod and a valve aperture with which the valve body is capable of being contacted, the guide hole having a contracted hole portion formed at a first portion thereof and an enlarged hole portion formed at a second portion thereof  
 a cooling medium inlet port disposed on an upstream side of the valve aperture for introducing a cooling medium of discharge pressure from the compressor, and  
 a cooling medium outlet port disposed on a downstream side of the valve aperture and capable of communicating with a crank chamber of the compressor;  
   an electromagnetic actuator including 
 a coil,  
 a cylindrical stator disposed on the inner peripheral side of the coil,  
 a sucking member secured to the stator, and  
 a plunger capable of cooperating with the coil and moving the valve rod in a direction of opening or closing the valve aperture;  
   a pressure sensitive chamber which is formed on the inner peripheral side of the stator and over the sucking member and to which an inlet pressure is introduced therein from the compressor;    a pressure sensitive driving member disposed in the pressure-sensitive chamber; and    an operating rod interposed between a pressure sensitive driving member and the plunger;    wherein 
 the valve body is designed to be moved in the valve-closing direction as the plunger is moved in a first direction and  
 the valve body is designed to be moved in the valve-opening direction as the operating rod is pushed in a direction opposite the first direction by the actuation of the pressure sensitive driving member;  
   wherein 
 the diametrally reduced rod portion is adapted to be slidingly inserted into the contracted hole portion, and  
 the valve rod includes an equalizing hole for introducing a cooling medium pressure of the cooling medium outlet port into an equalizing pressure introducing chamber within the valve main body.  
   
   
   
       3 . The control valve of  claim 1  wherein the equalizing pressure introducing chamber comprises an area between the contracted hole portion and the enlarged rod portion.  
   
   
       4 . The control valve of  claim 2  wherein the equalizing pressure introducing chamber comprises an area between the contracted hole portion and the enlarged rod portion.  
   
   
       5 . The control valve of  claim 1 , wherein the valve rod includes an annular groove on an outer circumferential portion thereof designed to slidingly contact the enlarged hole portion of guide hole.  
   
   
       6 . The control valve of  claim 2 , wherein the valve rod includes an annular groove on an outer circumferential portion thereof designed to slidingly contact the enlarged hole portion of guide hole.  
   
   
       7 . The control valve of  claim 3 , wherein the valve rod includes an annular groove on an outer circumferential portion thereof designed to slidingly contact the enlarged hole portion of guide hole  
   
   
       8 . The control valve of  claim 4 , wherein the valve rod includes an annular groove on an outer circumferential portion thereof designed to slidingly contact the enlarged hole portion of guide hole.