Patent ID: 7775463

Claim:
An electromagnetic fuel injection valve, comprising a valve seat, moving element having a valve body at a tip end thereof, a fixed core, and a magnetic passage, magnetic flux being supplyable to the magnetic passage including an anchor of the moving element and the fixed core by an energized ring-shaped coil such that a magnetic attraction force is generated in a magnetic attraction gap between an end surface of the anchor and an end surface of the fixed core to cause the moving element to be attracted to a fixed core side and the valve body mounted at the tip end of the moving element is separated from a valve seat to open a fuel passage, wherein the fixed core is fixed to an inside of a pipe made of a magnetic metal material, the pipe having an annular magnetism restriction portion formed on an outer circumference of the pipe at a position defined by a circumference of the magnetic attraction gap, the anchor is disposed to face the fixed core with the magnetic attraction gap therebetween, and the moving element is disposed in the pipe to be reciprocatingly movable between the valve seat and the fixed core, and wherein the annular magnetism restriction portion is a ring shaped groove; the ring-shaped coil and a yoke which envelops upper and lower portions and a circumference of the ring-shaped coil are fitted to an outer side of the pipe, and a total inner circumference length of the magnetic passage except the magnetism restriction portion of the pipe is smaller than an outside diameter of the yoke.