Patent ID: 7428887

Claim:
An electromagnetically driven valve that is operated by an electromagnetic force, comprising: a valve element which includes a valve shaft, and which is reciprocated in a direction in which the valve shaft extends; an oscillating member which extends from a driving end, that is moved in conjunction with the valve shaft, to a pivoting end, and which is oscillated around a central axis that extends at the pivoting end; a support member that supports the oscillating member; and an electromagnet that is disposed so as to face the oscillating member, wherein the electromagnet includes a core made of magnetic material, and a coil wound in the core, wherein the central axis is surrounded by a cylindrical portion of the oscillating member, which is made of magnetic material, wherein the core has a cylindrical portion that faces the cylindrical portion of the oscillating member; and wherein the electromagnet includes an upper electromagnet that is positioned above the oscillating member and a lower electromagnet that is positioned below the oscillating member; a protrusion made of magnetic material, which extends toward the oscillating member, is provided in each of the cores of the upper electromagnet and the lower electromagnet at a portion on a driving end side; and when the oscillating member is placed at a neutral position, a distance between the cylindrical portion of the oscillating member and the cylindrical portion of the core of the upper electromagnet is different from a distance between the cylindrical portion of the oscillating member and the cylindrical portion of the core of the lower electromagnet, and a distance between the protrusion provided in the core of the upper electromagnet at the portion on the driving end side and the oscillating member is different from a distance between the protrusion provided in the core of the lower electromagnet at the portion on the driving end side and the oscillating member.