Patent ID: 7246632

Claim:
A manufacturing method for a normally-closed electromagnetic valve, the electromagnetic valve including: a body member having a receiving space and communication holes communicating with the receiving space; a moving core disposed within the receiving space so as to move in an axial direction of the receiving space; a valve seat which has a flow hole constituting a part of a flow passage of a fluid circuit, and is accommodated within the receiving space of the body member so as to be fixed to the body member; a valve element fixed to an end portion of the moving core, and located in the flow passage for closing the flow hole; a resilient member urging the valve element toward the valve seat; and a fixed core fixed to an end portion of the body, wherein the moving core to which the valve element is fixed and the resilient member are disposed in the receiving space of the body member so that the valve element is sandwiched between the valve seat and the resilient member, the manufacturing method comprising the steps of: press-fitting the fixed core into the receiving space of the body member so as to oppose to the moving core and the resilient member; locating the moving core and the fixed core within a magnetic circuit; applying a magnetic field by the magnetic circuit to generate electromagnetic attracting force so that the moving core together with the valve element are attracted toward the fixed core and separating the valve element from the valve seat; detecting a physical quantity of the fluid and controlling an inserting length of the fixed core while applying fluid to the flow passage so as to flow pass through the communicating hole and the flow hole in such a manner that: inserting the fixed core further toward the valve element against the urging force of the resilient member when the detected physical quantity still surpasses or under runs a predetermined value; and stopping to insert the fixed core when the detected physical quantity reaches the predetermined value.