1. Field of the Invention
The present invention is related to an electromagnetic valve apparatus for driving an open/close valve to open or close a high-pressure fuel passage in order to control fuel injection timing and fuel injection quantity used particularly in the fuel injection equipment of an internal combustion engine.
2. Description of the Related Art
Electromagnetic valve apparatus has been known for driving by utilizing electromagnetic force, an open/close valve to open or close a high-pressure fuel passage in order to control fuel injection timing and fuel injection quantity. The electromagnetic valve apparatus comprises a core with a coil embedded therein and an armature located adjacent to the core. The armature is attracted toward the core when magnetic flux generated by electric current in the coil passes through the armature, and thus a valve body connected to the armature is driven.
As the electromagnetic valve apparatus is composed such that the valve body sits on the valve seat in a state in which the armature is attracted toward the core to close the fuel passage, there must be a gap between the core and the armature in the state in which the armature is attracted toward the core. It is required that this gap is as small as possible for securing strong electromagnetic attraction.
However, heretofore, both the surfaces of the core and the armature facing each other have been shaped as flat surfaces (see FIGS. 1, 3, 4, and 5 of Japanese Laid-Open Patent Application No. 2003-193939, and FIGS. 1, 2, and 3 of Japanese Laid-Open Patent Application No. 2002-98024, for example). The valve apparatus has been composed to provide a sufficient initial gap between the surfaces of the core and the armature facing each other so that the end surface of the armature does not interfere with the surface of the core facing the end surface of the armature even when the armature is installed aslant. This is caused by insufficient accuracy of the component parts, since it is difficult from the standpoint of accuracy of the component parts to compose them so that the gap is even allover the surfaces.