Patent ID: 8430343

Claim:
A fuel injection valve comprising: a body having an injection hole to inject fuel and a seat portion located upstream of the injection hole in a fuel flowing direction; a needle valve to be linearly reciprocated in an axis direction of the body, fuel injection from the injection hole being prohibited when the needle valve is seated on the seat portion in a seating direction and being allowed when the needle valve is separated from the seat portion in a separating direction; a cylindrical movable core to be moved relative to the needle valve, the needle valve being moved in the seating direction when the movable core is moved in the seating direction, the needle valve being moved in the separating direction when the movable core is moved in the separating direction; an electromagnetic driving portion to generate magnetic attraction force to attract the movable core in the separating direction by being supplied with electricity; and a biasing portion to contact and bias the movable core in the seating direction, wherein the needle valve has a first engagement part and a second engagement part to be engaged with the movable core, the movable core has a first engagement part to be engaged with the first engagement part of the needle valve, and a second engagement part to be engaged with the second engagement part of the needle valve, one of a set of the first engagement part and the second engagement part of the needle valve and a set of the first engagement part and the second engagement part of the movable core is defined by two inner faces of a recess opposing to each other in the axis direction, and the other set is defined by two outer faces of a projection opposing to the inner faces, respectively, the projection being movable between the inner faces in the axis direction in a state that the projection is located in the recess, the movable core is restricted from being moved in the seating direction relative to the needle valve when the first engagement part of the needle valve and the first engagement part of the movable core are engaged with each other, the movable core is restricted from being moved in the separating direction relative to the needle valve when the second engagement part of the needle valve and the second engagement part of the movable core are engaged with each other; a first distance defined between the first engagement part of the needle valve and the second engagement part of the needle valve is larger than a second distance defined between the first engagement part of the movable core and the second engagement part of the movable core, The electromagnetic driving portion has an attracting part to attract and contact the movable core when the electromagnetic driving portion is activated, a third distance being defined between the attracting part and a part of the movable core to contact with the attracting part, and the third distance is longer than the difference between the first distance and the second distance.