Fuel injection device having stationary core and movable core

A fuel injection device comprising:

• a tubular member;
• a stationary core that is press fitted into the tubular member and has a tapered annular outer surface section, which is arranged in an outer peripheral wall of a downstream end portion of the stationary core and is tapered toward a downstream end of the stationary core at a taper angle of 2 to 60 degrees to have a reduced outer diameter in the tapered annular outer surface section;
• a movable core that is arranged on a downstream side of the stationary core and is magnetically attractable to the stationary core;
• a coil that is arranged around the tubular member and forms a magnetic circuit in the tubular member, the stationary core and the movable core;
• a valve body that is coaxial with the tubular member, wherein the valve body includes:
• a fuel injection hole that is located at a downstream end of the valve body;
• and
• a valve seat that is located upstream of the fuel injection hole;
• and
• a valve member that moves together with the movable core and is seatable against the valve seat, wherein:
• the valve member closes the fuel injection hole when the valve member is seated against the valve seat;
• and
• the valve member opens the fuel injection hole when the valve member is lifted away from the valve seat.

A fuel injection device comprising:

• a tubular member;
• a stationary core that is press fitted into the tubular member and has a reduced diameter portion in a downstream end portion of the stationary core, wherein an annular space is defined between an inner peripheral wall surface of the tubular member and an outer peripheral wall surface of the reduced diameter portion of the stationary core, and an axial length of the annular space is in a range of 1.0 to 10 mm;
• a movable core that is arranged on a downstream side of the stationary core and is magnetically attractable to the stationary core;
• a coil that is arranged around the tubular member and forms a magnetic circuit in the tubular member, the stationary core and the movable core;
• a valve body that is coaxial with the tubular member, wherein the valve body includes:
• a fuel injection hole that is located at a downstream end of the valve body;
• and
• a valve seat that is located upstream of the fuel injection hole;
• and
• a valve member that moves together with the movable core and is seatable against the valve seat, wherein:
• the valve member closes the fuel injection hole when the valve member is seated against the valve seat;
• and
• the valve member opens the fuel injection hole when the valve member is lifted away from the valve seat.