Patent ID: 6102668
Filing Date: 2000-08-15
Classification: F04B,F16K

Abstract:
An electromagnetic control valve comprising:a valve member disposed in a valve chamber formed in an upper main body and a valve main body;a valve seat with which said valve member sealingly contacts, said valve seat being formed in a valve opening in a passage between the valve chamber and a discharge pressure supply port which is formed on a first side of the valve chamber and which communicates with a discharge duct of a compressor;a crankcase pressure port which communicates with a crank chamber of the compressor;a valve guide extending from said crankcase pressure port to said discharge pressure supply port;a valve rod reciprocally disposed in said valve guide;a plunger for displacing said valve member in a valve closing direction via an axially movable connecting rod which is disposed through an opening formed in the upper body, said plunger being disposed on a second side of the upper main body and axially displaceable by force selectively produced by an electromagnetic coil;a pressure equalizing passage which is formed through the valve main body and which communicates the valve chamber with said crankcase pressure port, said valve member selectively opening and closing said passage between the valve chamber and the discharge pressure port to control communication between the discharge pressure port and the crankcase pressure port via the pressure equalizing passage;a suction pressure port communicating with a suction side of the compressor;a pressure sensitive control mechanism disposed in a space leading to the suction side of the compressor, said pressure sensitive control mechanism comprises:a piston spring; anda piston which is operatively disposed between said piston spring and said valve rod to fluidly separate said crankcase pressure port and said suction pressure port and to have one side exposed to pressure in said crankcase pressure port and a second side exposed to pressure in said suction pressure port so as to be responsive to a pressure differential between the pressure in said crankcase pressure port and the pressure in said suction pressure port, and to apply a force indicative of the pressure differential to the valve member through the valve rod.