Abstract: The present invention relates to an improvement in an electromagnetic actuator which is composed of a yoke, a stationary core fixed to the yoke, a movable core capable of reciprocally moving with respect to the stationary core, a coil wound around the movable core for applying the first magnetic flux thereto when the coil is energized, and a permanent magnet fixed to the yoke or the movable core so as to apply the second magnetic flux which dividingly flows to the first magnetic flux in parallel thereto. This improved electromagnetic actuator is characterized that it satisfies the condition (a);(a) 0.5>R.sub.1 /R.sub.0 >0wherein,R.sub.1 represents the magnetic reluctance of the magnetic pass of one divided magnetic flux generated by the permanent magnet, including the magnetic reluctance of the gap d.sub.1 between one pole face of the movable core and one pole face of the yoke;R.sub.

Abstract: A step motor comprising magnetic stationary members (1,11) containing a plurality of series of magnetic poles (1a, 1b, . . . 11a, 11b, . . . ) arranged at a predetermined regular pitch; a magnetic movable member (4) containing a plurality of series of magnetic poles (4a, 4b, . . . 41a, 41b . . . ) arranged at a predetermined regular pitch different from the magnetic poles series (1a, 1b, . . . 11a, 11b, . . . ), each magnetic pole series (4a, 4b, . . . , 41a, 41b,) having a magnetic surface opposing the magnetic surface of each of the pole series (1a, 1b, . . . , 11a, 11b, . . . ) through a gap; electric coils (2a, 2b . . .

Abstract: An electromagnetic actuator according to the present invention comprises(a) a casing mainly consisting of a stationary iron core (1) or a combination of a stationary iron core (1) and a yoke, (1b), the casing being formed with at least one of opening;(b) one or a pair of movable iron core (2) as an actuating member, capable of reciprocally moving through the opening of the casing;(c) an electric winding element (4) arranged in the casing for applying a first magnetomotive force to the movable iron core (2) when an electric current is flowed through the winding element (4);(d) a permanent magnet (5) being so arranged in the casing as to apply the second magnetomotive force to the movable iron core; and(e) a bias force generating means (3) for applying a mechanical force or the first magnetomotive force to the movable iron core (2), wherein the improvement is characterized that a permanent magnet (5) is so arranged in the casing as to apply the second magnetomotive force in parallel to the first magnetomotive f