Patent ID: 8104698

Claim:
An electro-magnetic fuel injection valve, comprising: a movable part, including a cylinder-shaped anchor, a plunger, located in the center of said anchor, and a valving element, placed in the apex of said plunger, a fixed core having a fuel introduction hole in the center to introduce fuel to the central area, and a magnetic coil to supply magnetic flux to the magnetic flux lines including the magnetic gap provided between the end face of said anchor and the end face of said fixed core; and allowing magnetic attraction force generated between the end face of said anchor and the end face of said fixed core by the magnetic flux penetrating through said magnetic gap to attract said anchor to the side of said fixed core, thus driving said movable part to pull the valving element off the valve seat permitting the fuel passage in the valve seat to be opened, wherein: said anchor includes: a concave part foamed in the location facing the end part of the fuel introduction hole of the fixed core in the central portion of the anchor, convex areas formed at intervals in the circumferential direction at the end faces of the anchor in contact with the end faces of the fixed core, concave areas formed in the remaining portions in the convex area at the end faces of the anchor, and a plurality of through holes, one end of each of the through holes being open in said concave areas and the other end of each of the through holes being open around said plunger on the end face of the opposite side of the fixed core; the one end of the plurality of through holes is partly opened to the inner side of the concave part while a remaining part of the one end is opened to the concave areas opposed to an edge surface of the fixed core; the convex areas are formed to the outer circumferential side of the concave part and the concave areas are formed to the outer circumferential side of the convex areas; and the remaining part of one end opened to the concave areas intervenes between the convex areas adjoining to each other in a circumferential direction.