Patent ID: 8397759

Claim:
An electromagnetic spool valve comprising: a main body including a valve body having plural ports through which pressure fluid flows in and out and a housing which is connected to one end of the valve body; a linear solenoid section including a coil wound around a coil bobbin, a fixed core, and a movable core that is attracted toward the fixed core when electric current is supplied for the coil, each installed in the housing; and a valve operating mechanism comprising a first spool and a second spool coaxially provided in inner space of the valve body so as to switch a state of communication and discommunication among the plural ports, wherein the valve operation mechanism is provided with a first spring member between the first and second spools, and with a second spring member between one end of the valve body and the second spool such that a spring load of the second spring member is set to be greater than a spring load of the first spring member; wherein the switching of the state of communication and discommunication among the plural ports is carried out by a three-state switching control including: an off state with no electric current supplied for the linear solenoid section; a first lift state with electric current supplied for the linear solenoid section, so as to let the movable core positioned at an intermediate position; and a second lift state with electric current supplied for the linear solenoid section, so as to let the movable core positioned at a displacement terminal position; and wherein the plural ports comprise at least a first inlet port, a second inlet port, a first outlet port, a second outlet port and a third outlet port; in the off state of the linear solenoid section, the first inlet port and the first outlet port are in communication with each other, so as to lead pressure fluid out from the first outlet port; in the first lift state, the first inlet port and the second outlet port are in communication with each other, so as to lead the pressure fluid out from the second outlet port; and in the second lift state, the first inlet port and the first outlet port are in communication with each other, so as to lead the pressure fluid out from the first outlet port, and the second inlet port and the third outlet port are in communication with each other, so as to lead the pressure fluid out from the third outlet port.