Electromagnetic fuel injection valve

An electromagnetic fuel injection valve including:

• a valve housing (2) including a valve seat member (3), a fixed core (5) and a fuel intake cylinder (26) which are connected in a fore-and-aft direction, an inside of the valve housing (2) serving as a fuel passage, and the valve seat member (3) having a valve seat (8) and a valve hole (7) at a front end thereof;
• a coil (30) placed around an outer periphery of the valve housing (2), and electrified in order to excite the fixed core (5);
• and a valve assembly (V) which is housed in the valve housing (2), and opens and closes the valve hole (7) in cooperation with the valve seat (8) in conjunction with demagnetization and excitation of the fixed core (5), the valve assembly (V) including a valve body (14), a movable core (12) and a valve shaft (13), the valve body (14) being detached from and seated on the valve seat (8), having a spherical basic shape, and having a plurality of passage portions (18) in an outer periphery thereof, the movable core (12) being slidably fitted into the valve housing (2), and the valve shaft (13) being integrally projectingly provided to a front end of the movable core (12) and connected to the valve body, having a diameter smaller than that of the movable core (12),
• characterized in that the valve seat member (3) is provided with:
• a valve body guide hole (15) which continues to the valve seat (8) and slidably guides the valve body (14);
• and a large-diameter hole (17) which continues to a rear end of the valve body guide hole (15) via a taper hole (16), and whose diameter is larger than that of the valve body guide hole (15), the fixed core (5) is provided with a first longitudinal hole (19) which communicates with an inside of the fuel intake cylinder (26), a second longitudinal hole (20) communicating with the first longitudinal hole (19) is provided, stretching from the movable core (12) to the valve shaft (13), the valve shaft (13) is provided with a single traverse hole (21) which makes the second longitudinal hole (20) open to the large-diameter hole (17), and the valve shaft (13) includes a hollow shaft portion (13a) having the second longitudinal hole (20);
• and a solid shaft portion (13b) which is solid, has a diameter smaller than that of the hollow shaft portion (13a), and continues to a front end of the hollow shaft portion (13a), and a cylinder-shaped passage (25) is defined between the solid shaft portion (13b) and an inner peripheral surface of the valve body guide hole (15) by plunging a front-end portion of the solid shaft portion (13b) into the valve body guide hole (15), and the hollow shaft portion (13a) is provided with the traverse hole (21).