Patent ID: 7097151

Claim:
An electromagnetic fuel injection valve comprising a valve housing ( 2 ) having a valve seat ( 8 ) at one end thereof, a fixed core ( 5 ) connected to the other end of the valve housing ( 2 ), a valve body ( 18 ) that is housed within the valve housing ( 2 ) and that carries out opening and closing operations in cooperation with the valve seat ( 8 ), a movable core ( 12 ) integrally connected to the valve body ( 18 ) and disposed so as to oppose the fixed core ( 5 ), a valve spring ( 22 ) urging the valve body ( 18 ) in a valve-closing direction, and a coil ( 30 ) that is disposed so as to surround the fixed core ( 5 ) and that by energization makes the fixed core ( 5 ) attract the movable core ( 12 ), thereby opening the valve body ( 18 ), the fixed core ( 5 ) being made of a high hardness ferrite magnetic material; characterized in that a cylindrical stopper element ( 14 ) is press-fitted and fixed to the movable core ( 12 ) so that the stopper element ( 14 ) projects toward the fixed core ( 5 ) from an attracting face ( 12 a ) of the movable core ( 12 ), the stopper element ( 14 ) surrounding the valve spring ( 22 ) and being made of a stainless steel that is nonmagnetic or is more weakly magnetic than the movable core ( 12 ), and an end face of the stopper element ( 14 ) and the attracting face ( 12 a ) of the movable core ( 12 ) are simultaneously ground so that the stopper element ( 14 ) defines a valve-opening limit for the valve body ( 18 ) by the end face of the stopper element ( 14 ) abutting against the attracting face ( 5 a ) of the fixed core ( 5 ) when the coil ( 30 ) is energized while maintaining an air gap (g) between the attracting faces ( 5 a, 12 a ) of the two cores ( 5 , 12 ), thus securing the air gap (g).