ELECTROMAGNETIC ACTUATOR WITH TORQUE-COMPENSATING POLES

摘要

of The Disclosure An electromagnetic actuator has a stator and an armature both made of magnetically permeable material and each having a plurality of projecting poles spaced apart from each other. The armature poles and stator poles cooperate with each other so that each pair of opposed pole faces of an armature pole and a stator pole form a narrow working air gap for passing magnetic flux between the opposed pole faces. An electrically energizable coil produces magnetic flux which passes through the poles of the armature and stator and across the working air gaps. Selected pairs of the opposed armature and stator poles form a substantially constant air gap so that the attracting magnetic force on the armature increases as the armature moves in a first direction relative to the stator and decreases as the armature moves in the opposite direction, and other pairs of the opposed armature and stator poles form a variable air gap so that the attracting magnetic force on the armature decreases as the armature moves in the first direction and increases as the armature moves in the opposite direction.