Patent ID: 7165574

Claim:
A valve device comprising: a valve chamber having an inlet port at one end and a valve seat at the other end; a valve housing containing the valve chamber; the valve chamber accommodating a spherical valve element which performs opening and closing operation to the valve seat, and a valve spring which urges the valve element in a closing direction; a push rod which penetrates a center hole of the valve seat and pushes the valve element in an opening direction; and an electromagnetic actuator which operates the push rod, the electromagnetic actuator including a coil housing which is made of a magnetic material and is coupled with the valve housing, a coil assembly which has a bobbin and a coil wound around the bobbin and is fit into the coil housing, a fixed core which is coupled with one end of the coil housing and is located in the bobbin, a movable core which is located movably in an axial direction in the bobbin while facing the fixed core, and is connected with the push rod, wherein a cylindrical valve guide member is fit into the valve chamber, the cylindrical valve guide member including a plurality of guide projections on an inner peripheral surface to guide opening and closing operation of the valve element, and wherein grooves between the plurality of guide projections serve as passages providing communication between the inlet port and the valve seat, wherein the movable core is constructed into a bottomed cylindrical shape, wherein the movable core is slidably fit to an outer peripheral surface of a guide core which is fixed to the other end of the coil housing and located in the bobbin, and wherein an axial attraction generated between the movable core and the guide core at the time of energizing the coil is smaller than an attraction generated between the movable core and the fixed core.