Power element and expansion valve using same

Abstract

Provided are a power element and an expansion valve using same that are capable of suppressing local deformation of a diaphragm while ensuring the transfer efficiency of a refrigerant. A power element includes a diaphragm; an upper lid member that is overlapped on one surface in the vicinity of the outer circumference of the diaphragm and forms a pressure working chamber PO with the diaphragm; a receiving member that is overlapped on another surface in the vicinity of the outer circumference of the diaphragm and forms a refrigerant inflow chamber LS with the diaphragm; and a stopper member housed in the refrigerant inflow chamber LS and in contact with the diaphragm, wherein the diaphragm is displaced within a range from a neutral position to a position displaced from the neutral position toward the upper lid member side.

1 . A power element comprising:
 a diaphragm;   an upper lid member that comes into contact with an outer circumferential portion of the diaphragm and that forms a pressure working chamber with the diaphragm;   a receiving member that comes into contact with an outer circumferential portion of the diaphragm and that forms a refrigerant inflow chamber with the diaphragm; and   a stopper member housed in the refrigerant inflow chamber and in contact with the diaphragm,   wherein the diaphragm is displaced within a range from a neutral position to a position displaced from the neutral position toward the upper lid member side.   
     
     
         2 . The power element according to  claim 1 , wherein the diaphragm is restrained by the receiving member via the stopper member within a range from the neutral position to a position displaced from the neutral position toward the upper lid member side. 
     
     
         3 . The power element according to  claim 1 , wherein a support point on a receiving member side is closer to an outer circumference of the diaphragm than a support point on an upper lid member side. 
     
     
         4 . An expansion valve comprising:
 a power element;   a valve main body provided with a refrigerant flow path communicating with a refrigerant inflow chamber, having a valve chamber and a valve seat;   a valve element disposed in the valve chamber;   a coil spring that presses the valve element toward the valve seat; and   an operation rod having one end in contact with the valve element,   
       wherein:
 the power element includes a diaphragm, an upper lid member that comes into contact with an outer circumferential portion of the diaphragm and that forms a pressure working chamber with the diaphragm, and a receiving member that comes into contact with an outer circumferential portion of the diaphragm and that forms the refrigerant inflow chamber with the diaphragm, and 
 the diaphragm is displaced within a range from a neutral position to a position displaced from the neutral position toward the upper lid member side by a pressure difference between a pressure working chamber of the power element and the refrigerant inflow chamber, and drives the valve element against a biasing force of the coil spring. 
 
     
     
         5 . The expansion valve according to  claim 4 , wherein:
 the power element includes a stopper member housed in the refrigerant inflow chamber and in contact with the diaphragm; and   the diaphragm is restrained by the receiving member via the stopper member within a range from the neutral position to a position displaced from the neutral position toward the upper lid member side.