Abstract: There is provided a long-proportional-stroke force motor whose force vs. stroke characteristic provides a long stroke in which a constant force is output proportional to the exciting current in magnitude without involvement of problems in actual use, and which does not impose any limitations on the stroke so as to effectively use the stroke. A long-proportional-stroke force motor 1 includes a magnetic circuit configured such that a spacer 12 made of a non-magnetic material intervenes between a guide 11 made of a magnetic material and a sleeve 13 made of a magnetic material, and an armature 3 provided movably within the magnetic circuit.

Abstract: A servo valve has a miniature force motor embedded in a main fluid chamber to directly operate between two nozzles to generate a differential pressure in two ports. The miniature force motor includes two disc ring-shaped magnets in opposing magnetic orientation, an armature base and poppet ends of magnetic material coupled to an armature shaft having pilot ends that interface to form the pilot stage valves at each armature shaft end. The armature shaft extends through a center hole in the magnets, armature base, and the poppet ends and engages bearing elements at each end allowing lateral armature motion. Two elastic members provide restoring forces to the armature assembly. Guide/stops have shaped magnetic surfaces to control the magnetic path and to linearize the force versus stroke and to increase the proportional stroke of the armature.

Abstract: A rotary actuator has a stator having plural permanent magnets 1a and 1b; a rotor having a rotor core 3 which plural salient poles 3a and 3b are formed at, and one or more rotor coils 5 are wound around; an electromagnetic torque generating portion A comprising the stator and the rotor which, by supplying an electric current to the rotor coils 5, generates an electromagnetic torque which displaces a relative angle position of the rotor and the stator in approximate proportion to the magnitude of the electric current; and a coil spring 36 biased in approximate proportion to the magnitude of the relative angle displacement of the rotor and the stator, and thereby generating a torque in the direction opposite to the direction of the electromagnetic torque.

Abstract: The present invention provides an electromagnetic clutch that can restrict output torque to a predetermined range against the variation of the voltage of the power supply and the environmental temperature. The electromagnetic clutch comprises: an armature; a rotor that attracts the armature; a plurality of slits that are formed in the armature and the rotor around circumferential directions thereof; and a plurality of annular attraction surfaces that are formed on the armature and the rotor which face each other. At least one of the circumferential sections cut in the circumferential direction at the position in the armature and the rotor where respectively face an inner slit wall of the other party, and at least one of the attraction surfaces are substantially equal to each other in area.

Abstract: An electromagnetic clutch comprising a stator yoke, a rotor and an electromagnetic coil, the stator yoke comprising a thick-walled cylindrical portion and an annular large-outside-diameter portion contiguous at an end thereof perpendicularly to the thick-walled cylindrical portion, a radial section cut from the central axis of the cylindrical portion being L-shaped, a stepped portion being formed at a radially intermediate position of the annular large-outside-diameter plate portion, the stepped portion having an annular vertical surface perpendicular to the radial direction, the rotor comprising an annular small-outside-diameter plate portion, an inner cylindrical portion contiguous at an end thereof perpendicularly to an inner end of the annular small-outside-diameter plate portion, and an outer cylindrical portion contiguous at an end thereof perpendicularly to an outer end of the annular small-outside-diameter portion, the rotor covering an upper end side of the thick-walled cylindrical portion of the sta

Abstract: An electromagnetic clutch comprising a stator yoke, the stator yoke comprising a cylindrical portion with a slant inner surface and an annular base plate portion contiguous at an end thereof perpendicularly to one end of the cylindrical portion with the slant inner surface, a radial section cut from the central axis of said cylindrical portion with the slant inner surface being L-shaped, and a rotor, the rotor comprising an annular plate portion, a truncated inverse circular cone portion contiguous at an end thereof perpendicularly to an inner end of the annular plate portion and having a central circular through hole, and an outer cylindrical portion contiguous at an end thereof perpendicularly to an outer end of the annular plate portion, the rotor covering an upper end side of the cylindrical portion with the slant inner surface of the stator yoke and also covering an electromagnetic coil, the truncated inverse circular cone portion being disposed so as to be loosely fitted inside the cylindrical portion w

Abstract: Salient poles 3a formed at a rotor core 3 are structured such that their facing surfaces facing permanent magnets 1a and 1b are formed in the shapes of circular arcs of which the radii at the circumferential center portion and at the circumferential end portions are different from each other. The angle between the line connecting one of the circumferential outlines of one of the salient poles 3a and the rotation center of the rotor core 3 and the line connecting the other circumferential outline of the same salient pole 3a and the rotation center of the rotor core 3 is not less than 100 degrees. Permanent magnets 1a and 1b are structured such that the radial thickness B of each circumferential end portion is from 90% to 95% of the radial thickness A of each circumferential center portion, so as to have circular arc surfaces of which center positions are different from each other.

Abstract: A rotary actuator has a stator having plural permanent magnets 1a and 1b; a rotor having a rotor core 3 which plural salient poles 3a and 3b are formed at, and one or more rotor coils 5 are wound around; an electromagnetic torque generating portion A comprising the stator and the rotor which, by supplying an electric current to the rotor coils 5, generates an electromagnetic torque which displaces a relative angle position of the rotor and the stator in approximate proportion to the magnitude of the electric current; and a coil spring 36 biased in approximate proportion to the magnitude of the relative angle displacement of the rotor and the stator, and thereby generating a torque in the direction opposite to the direction of the electromagnetic torque.

Abstract: A servo valve has a miniature force motor embedded in a main fluid chamber to directly operate between two nozzles to generate a differential pressure in two ports. The miniature force motor includes two disc ring-shaped magnets in opposing magnetic orientation, an armature base and poppet ends of magnetic material coupled to an armature shaft having pilot ends that interface to form the pilot stage valves at each armature shaft end. The armature shaft extends through a center hole in the magnets, armature base, and the poppet ends and engages bearing elements at each end allowing lateral armature motion. Two elastic members provide restoring forces to the armature assembly. Guide/stops have shaped magnetic surfaces to control the magnetic path and to linearize the force versus stroke and to increase the proportional stroke of the armature.