Patent ID: 6476701
Filing Date: 2002-11-05
Classification: H02K

Abstract:
An electromagnetic actuator comprising:a rotatable rotor comprising a magnet having at least one magnet member magnetized so as to have a north pole and a south pole and disposed on part of a peripheral portion of said rotor, said north pole and said south pole being circumferentially spaced on said rotatable rotor, and said magnet being rotatable with said rotatable rotor; at least one magnetomotive force source assembled with said rotatable rotor; and at least one magnetic path forming member assembled with said rotatable rotor and said at least one magnetomotive force source so as to form three pole pieces on a peripheral edge of an opening receiving said rotatable rotor, including a center pole piece and two end pole pieces, such that when said at least one magnetomotive force source is not energized, two magnetized surfaces of said magnet corresponding to said north pole and said south pole face said center pole piece; wherein said two end pole pieces are each in contact with said center pole piece or are adjacent to said center pole piece with a gap therebetween; wherein said three pole pieces include at least one adjacent pair of pole pieces that are connected by a magnetic path of said at least one magnetic path forming member; and wherein one of said end pole pieces has an outwardly projecting space that is provided asymmetrically in said opening such that lengths of portions of said two end pole pieces that face said rotor are different from each other.