Electromagnetic fuel injector

Claim 1

In an electromagnetic fuel injector including: a valve housing provided with a fuel injection nozzle and a valve seat at its front end and defining a guide hole extending along the axis of said valve housing, a valve body slidably inserted into said guide hole, a compression spring adapted to normally urge said valve body so as to close said fuel injection nozzle, an armature fixed to the rear end of said valve body, a fixed magnet core disposed opposite to the rear end of said armature and having a fuel passage extending through the central portion of said core, an exciting coil surrounding said fixed magnet core, and an electromagnetic housing combining said valve housing with said fixed magnet core, said electromagnetic fuel injector being adapted to discharge pressurized fuel when said exciting coil receives a control signal to open said valve body, the improvement wherein said valve body comprises a spherical valve member and a hollow cylindrical slide member integral with said valve member which is adapted to slide along said guide hole and the interior of which hollow slide member is a fuel passage, said slide member defining openings at its front and rear ends for passing liquid fuel therethrough, the outer diameter of said slide member being at all points less than the diameter of said hole and the outer diameter of said spherical valve member being less than the outer diameter of said slide member, and said armature being substantially of a hollow cylindrical cross-section of inner diameter greater than the diameter of said compression spring, whereby said compression spring applies force directly to said valve body.