Patent ID: 6076550
Filing Date: 2000-06-20
Classification: F16K,H01F,Y10T

Abstract:
A solenoid for driving a plunger, comprising:an electromagnetic coil having a region-defining member made of a nonmagnetic material for defining a moving region in which said plunger is moving, and a coil winding portion wound around said region-defining member to generate a magnetic field of a first magnetic flux path penetrating said moving region along a direction of moving of said plunger, said electromagnetic coil exerting a magnetic force of said first magnetic flux path on said plunger;an irregular magnetic field forming member made of a magnetic material and arranged at an external side of a partitioning face formed to partition said moving region and on an end side of said region-defining member opposed to said plunger, said irregular magnetic field forming member forming a second magnetic flux path of the magnetic field formed by said electromagnetic coil at the external side of said partitioning face from said end side of said region-defining member, said irregular magnetic field forming member exerting a magnetic force of said second magnetic path from a top end of said irregular magnetic field forming member on said plunger via said partitioning face; andan encapsulating member having an encapsulating portion formed to be able to arrange one of said irregular magnetic field forming members on said end side of said region-defining member opposed to said plunger, said irregular magnetic field forming members having different lengths from said end side of said region-defining member to said encapsulating member at the external side of said partitioning face.