Patent ID: 6994313

Claim:
A pressure control valve including a body to which a valve element is assembled so as to be movable and which is provided with a pressure detecting chamber, wherein the valve element opens a valve port when pressure of a fluid provided in the pressure detecting chamber is lower than a predetermined reference pressure, and the valve element closes the valve port when the fluid pressure in the pressure detecting chamber is higher than the predetermined reference pressure, the pressure control valve comprising: a shaft hole formed through a wall surrounding the pressure detecting chamber of the body, the shaft hole being provided with the valve port located at a side away from the pressure detecting chamber; a communication shaft inserted through the shaft hole and having an end protruding from the valve port and provided with the valve element; biasing means for biasing the valve element so that the valve element is pressed against an opening edge of the valve port thereby to close the valve port; a branch hole branched from a middle portion of the shaft hole and communicating with the valve port; a sealing member sealing a gap between the communication shaft and an inner wall of the shaft hole, said inner wall being located nearer to the pressure detecting chamber than the branch hole; a pressure sensing cylindrical member having a closed end fixed to the communication shaft in the pressure detecting chamber and an open end directed opposite the valve element; a diaphragm provided on the open end of the pressure sensing cylindrical member; a terminal wall provided on the body so as to be opposed to the diaphragm; and a stretching member stretched between the diaphragm and the terminal wall, the stretching member being subjected to a spring force the diaphragm receives when the fluid pressure in the pressure detecting chamber is lower than the predetermined reference pressure, thereby moving the valve element to the opening side.