PURPOSE: To reduce residual flux in the colliding face between a flat movable core and a magnetic ring, while to shorten the valve-close operating time of flat movable core and to improve the durability by securing a non-magnetic thin plate and hardening the surface more than the basic material.
CONSTITUTION: Upon supply of exciting current, the upper face of flat movable core 20 will contact tightly against a non-magnetic thin plate 30 of a magnetic ring 13. Upon interruption of exciting current, magnetic adhering force is reduced because of said plate 30 to eliminate the residual flux abruptly. Consequently, said core 20 will move quickly in the valve-close direction to seat a ball valve body 23 in a valve seat 26 thus to close the fuel injection hole 27 instantaneously. Since said plate 30 is harder than the basic material, abrasion due to collision of the upper face of said core 20 against the lower face of said ring 13 is reduced resulting in improvement of the durability.
AIKI MASANORI
KOJIMA FUMIO
SAKAI TATSUO
