Abstract: A rotary idle-speed actuator for controlling a throttle cross-section in a line carrying combustion air for an internal combustion engine has an actuating motor with a stator and a rotor. The rotor is mounted on a shaft of a throttle member which more or less opens a control opening. The rotor has a cup-shaped form with a bottom and a cylinder-jacket-shaped wall. The stator has field windings and is arranged together with the field windings inside the rotor, and the stator is mounted only at its end which is opposite to the bottom of the rotor.

Abstract: A compact electromagnetic actuator having at least one stable position in the absence of current and an area of constant torque or force under a constant current. The actuator includes a movable member having at least one thin portion magnetized normal to the displacement direction thereof, as well as a stator structure defining an air gap therebetween. The stator structure includes first and second magnetic circuits separated by an air gap. The first magnetic circuit includes at least one energization electric coil and polar portions. At least one of the polar portions has a side bevelled strip inducing an adjustment for displacements near limit-stop of the movable member.

Abstract: The invention contemplates a rotary valve which uses a brushless DC-motor to directly drive the flow control member of the valve. The motor is of toroidal-torque variety, with a wound stator that is fixed to the valve body, and a rotor which is fixed to the valve member. In a first embodiment, one polarity of transient stator excitation drives the rotor in one direction, from one to the other magnetically latched end of a limited angular excursion, and the opposite polarity of transient stator excitation drives the rotor in the opposite direction, to reverse the magnetically latched condition of the rotor and, therefore, of the valve member. In a second embodiment, a torsion spring is connected to apply torque in opposition to rotor displacement from one of the limits of its angular excursion, and the extent to which the valve member is operated is a function of the instantaneous magnitude of stator excitation.

Abstract: In a cross-coil rotary magnet device, a rotor (32) which is mounted rotatably together with a shaft (35) is formed of a permanent magnet (33) with diametrically opposite permanent magnet poles and a coil arrangement (10, 11) with coils which are arranged at an angular distance apart of, in particular, 90.degree.. For receiving the coils there is provided a coil body (14) which is divided into two parts (15, 16) and in which bearings (36, 37) of the shaft (35) of the rotor (32) are shaped in such a manner that the shaft protrudes out of the coil body at least one front outer end (12). One of the two parts (15, 16) of the coil body (14) has on this outer end tab-shaped clips (24-27) for the clamping attachment of an intermediate body (2). Bores (38-43) for connecting pins (4-7) are provided in the coil body parallel to the shaft (35). The cross-coil rotary magnet device can thus be adapted to numerous applications.

Abstract: A limited angle torque actuator produces a substantially constant torque over an excursion angle of 90 degrees or more. The actuator uses a core made from a highly permeable magnetic material such as soft iron. In a preferred embodiment, one or more permanent magnets are attached to the outer surface of the cylindrical core. In another embodiment, the permanent magnets are spaced apart from a stationary core to create an air gap therebetween. When current flows through a coil wound on the stator, first and second stator poles are created which interact with the permanent magnets to rotate the rotor assembly.

Abstract: An electromagnetic coupling device is proposed to obviate drawbacks in the conventional coupling devices, namely, expensive production cost brought about by such step as caulking with rivet or by screw setting in making armature and spring assembly. The proposed electromagnetic coupling devices uses an armature and spring assembly which composed of a ring shaped flat spring formed with a plurality of axially extending protrusions instead of a leaf spring, and an armature having a radially extending projections for effecting spring action to the armature. The ring shaped flat spring in the modified armature/spring assembly can be fabricated with less procuction cost and can be readily fitted to to the armature with less man hours, thereby the production cost can be remarkably reduced.

Abstract: To reduce noise, impact forces and bouncing, the shaft of a rotary solenoid is provided with a dampening mechanism which generally includes a resilient dampening element and a cooperating collar which are axially disposed about the rotating shaft of the solenoid. Following activation of the rotary solenoid, the resilient element is drawn into contact with the housing, developing friction between the rotating resilient element and the housing of the rotary solenoid which operates to bring rotation of the shaft to a controlled stop.

Abstract: An encoder wheel (60) is provided for monitoring a peristaltic pump (20). The encoder wheel (60) provides a plurality of equispaced sectors (62) and a reference sector (66) provided at the outer radius of the encoder wheel (60). A vane slit (68) is provide radially offset from the sectors (62,66). A pair of optical couplers (72,74) are provided to read the sectors (62,66) and the vane slit (68).

Abstract: A motor-compressor unit comprising a vibration motor (1) having a single-part magnetizable stator (2) in the form of a W, arcuate air gaps (9, 10) being formed between the peripheral surface (6) of the central limb 3 of the W and each of the outer limbs (4, 5) of the W, and an armature (11) which is reciprocatingly pivotable about a motor shaft (12). The armature comprises at least one permanent magnet pole element (13), at least one coil (16, 17) arranged on the stator, an alternating current through the coil producing an oscillating movement of the armature (11), a compressor (21) having a linearly reciprocating piston (24) which is coupled to the armature (11), the coupling (25) being arranged diametrically opposite the pole element (13) relative to the motor shaft (12).

Abstract: A high torque rotary solenoid is disclosed employing attracting and repelling forces of permanent magnets to induce rotary motion is disclosed. Four arrays of magnets are located on a stator and rotor and are arranged along the axis of rotation of a shaft. Two magnet arrays are located on the stator, and two magnet arrays are located on the rotor. Each of the magnet arrays on the stator is arranged to come in close proximity to one of the magnet arrays on the rotor when the rotary shaft is positioned to the clockwise or counterclockwise rotary motion limits. The rotary solenoid has two rotational positions, each position corresponding to the mechanical limits of rotational movement.

Abstract: An actuator is disclosed, in which an movable armature and a permanent magnet mounted on a stationary yoke are disposed to face each other with a small gap. The armature has at least one pair of protruding poles which are movable along a predetermined path. The permanent magnet comprises plural pairs of juxtaposed magnetic pieces whose polarities are opposite to each other. The plural pairs of magnetic pieces are arranged in juxtaposition with each other at positions adjacent to the path of the corresponding protruding pole so that adjacent two magnetic pieces of adjacent two pairs have the same polarity with each other. The permanent magnet generates such a magnetic pattern that the amount thereof gradually decreases from both ends of the path of each protruding pole towards the boundary of the magnet pieces of the corresponding pair to avoid the influences due to the reluctance torque and the drive torque.

Abstract: The present invention relates to a 3-position rotational actuator which obtains three stable points by two pairs of field poles, in which the magnetic flux to a rotor due to one pair of field poles of a stator for maintaining the rotor at the first stable point is substantially equal to the magnetic flux to the rotor due to the other pair of field poles of the stator for rotating the rotor from the first stable point. The magnetic flux density of the other pair of field poles of the stator applied to the rotor is set to be smaller than the magnetic flux density of the one pair of field poles of the stator. Therefore, the detention torque can be maintained to the same degree and the drive torque can be improved.

Abstract: A solenoid has a coil with an outer core and an inner core. The cores provide the magnetic circuit around the coil. The inner core includes a rotor which has radially extending armatures. The armatures are positioned in gaps between radially extending poles of the outer core so as to form air gaps between the poles and the armatures. When the coil is energized, the armatures are attracted to the poles and cause the rotor to rotate, thereby closing the air gaps. The shaft is coupled to the rotor through a drive mechanism so as to rotate with the rotor. The shaft is made of a material with a relatively high magnetic permeability, as are the inner and outer cores, so that the shaft is magnetically coupled to the inner core rotor. When the rotor stops rotating, the shaft also stops. A return spring returns the rotor to its deenergized position when the coil is deenergized, recreating the air gaps. The drive mechanism allows the shaft to remain stationary while the rotors return to the deenergized position.

Abstract: In the disclosed device, a pair of magnets supported in the ends of a C-shaped yoke bias an armature into one of the two rotary positions. A short pulse to a coil about the center of the yoke induces a short term magnetic field that supplements the polarity at one end of the yoke so as to either maintain the armature in its biased position or swing the armature to its other biased position. A subsequent pulse, producing a field in the opposite direction, returns the armature to its first position. In each case, the magnets retain the armature in its biased position even after the pulse stops. The armature pivots between portions of the yoke magnetized by the same magnet.

Abstract: A pressure regulator continuously actuates the relative axial position and the tangential position of an armature relative to a valve body into the desired position so as to deliver a fluid at a constant pressure. The tangential position of the armature is determined in response to an electrical excitation of a coil resulting in a change in the magnetic forces applied to the armature. The axial position of the armature is adjusted in response to changes in the control pressure. The armature has a plurality of ports which enable fluid to enter and leave therefrom. The valve body has a plurality of ports in fluid communication with the armature ports. The armature has two elongated prongs. A compression spring is generally centrally disposed within the electromagnetic compartment of the armature. One end of the spring is secured to the armature and the other end of the spring is secured to the regulator housing.

Abstract: A directional control device for use in a movable toy such as a radio control car, which has a cylindrical magnet, a magnetic yoke disposed rotatably within the magnet and having an electromagnetic coil, and steering arms attached to driven wheels of the toy. The direction of the movable toy in motion can readily be changed selectively by applying a DC current of one polarity to the coil so as to electromagnetically rotate the yoke, thereby to turn the steering arms in conjuction with the rotating yoke.

Abstract: Limited angle torque motor includes a rotor assembly having one or more permanent magnets which are magnetized in the diametrical direction and a stator assembly including a pair of circumferentially spaced stator magnetic pole pieces, each having a stator pole flange at the opposite end thereof. Each stator pole piece has a greater circumferential width in the region of the respective stator pole flanges to increase the amount of magnetic material in such region where the flux density is the highest. Surrounding the stator assembly is a magnetic housing which desirably effectively has no air gap therein.

Abstract: Disclosed is here a rotary encoder having a recording medium including positional information arranged in a circumferential direction, sensors disposed opposing the positional information, and a driving shaft linked with a central position of the recording medium for detecting, based on a change in outputs from the sensors, the positional information of the recording medium rotated by means of the driving shaft. A link body is formed by achieving a bending work on an elastic plate such that bent lines of the elastic plate form a rectangular shape and that there are formed two pairs of opposing bent leg pieces, one of the two pairs of the opposing bent leg pieces is fixedly secured on the recording medium and the other one thereof is fixedly secured on a coupling body disposed in the proximity of the recording medium, and the driving shaft is inserted into and fixed on a shaft inserting hole formed in the coupling body.

Abstract: An electromagnetic adjustment device for performing mechanical rotational movements has two electromagnetically excitable pole pieces arranged opposite each other to form an opening partially surrounded by concave circular surfaces of the pole pieces. A rotary anchor of permanent magnetic material is rotatably supported in the opening. The anchor has two opposite circular surface sections and two opposite flat surface sections. The flat surface sections face the concave circular surfaces of the pole pieces when the rotary anchor is in a position signifying a center of its operational range. The radius of the concave circular surfaces is slightly larger than the radius of the circular surface sections of the rotary anchor forming north and south poles so that four air gaps are formed between the concave circular surfaces of the pole pieces and the circular surface sections of the rotary anchor.

Abstract: A rotary actuator in which there is a freely rotatable permanent magnetic armature between two stators. At least one of the stators produces an asymmetrical magnetic flux field that acts upon the magnetic field of the armature to cause the same to rotate.

Abstract: The magnetic rotation apparatus of the present invention has first and second rotors rotatably supported and juxtaposed. The first and second rotors are connected so as to be rotatable in opposite directions in a cooperating manner. A number of permanent magnets are arranged on a circumferential portion of the first rotor at regular intervals, and just as many permanent magnets are arranged on a circumferential portion of the second rotor at regular intervals. Each permanent magnet has one magnetic polarity located radially outward from the rotors, and has the other magnetic polarity located radially inward toward the rotors. The polarity of each permanent magnet, which is located radially outward from the rotors, is identical. When the first and second rotors are rotated in a cooperating manner, the phase of rotation of the permanent magnets of one rotor is slightly advanced from that of the permanent magnets of the other rotor. One of the permanent magnets of one rotor is replaced with the electromagnet.

Abstract: The limited angle rotary force motor includes an inner pole member having multiple permanent magnets disposed on the exterior thereof and a longitudinal bore in which a rotor shaft is journaled for rotation. An annular low inertia coil assembly is positioned in spaced relation around the permanent magnets by sets of spoke-like arms extending from the rotor shaft through transverse openings in the inner pole means. An annular ferritic stainless steel outer pole sleeve is located in spaced relation around the coil assembly to complete the magnetic circuit and withstand hydraulic system pressure to which the motor components are exposed. The outer pole piece is part of the casing or housing for the servovalve.

Abstract: A rotary solenoid providing opposite direction pivotal movement on opposite olarity d.c. energization. The solenoid has a pivoting shaft from which a permanent magnet armature having ends of opposite magnetic polarity extends transversely and oppositely. The armature is disposed between a pair of pole pieces each of which extends along the armature between its ends. The pole pieces are oppositely electromagnetically magnetized by a d.c. winding so that reversing the electrical polarity of the winding reverses the polarity of each pole piece and its attraction or repulsion of the armature ends. The pole pieces are opposite arms of a U-shaped ferromagnetic structure on which the winding is centrally wound, and the shaft is supported by a bearing in a nonferromagnetic bridge between the pole pieces.

Abstract: A set of magnetically responsive vanes are secured for rotation about their mass center of gravity in a given angular spacing. The vanes have corresponding magnetic field producing coils which are in a different angular spacing such that one coil and vane is aligned and a second coil and vane are misaligned. An electrical switch is coupled to the vanes for operation in response to rotation of the vanes. A current applied to one coil aligns its vane thereto and closes the switch. The closed switch applies a load current to a second coil whose vane is misaligned. When an overcurrent occurs, the corresponding resulting field aligns its vane and opens the switch. An off current applied to a coil can align a corresponding vane to also open the switch. The switch and actuator are dynamically balanced so that moments produced by shock and vibration do not operate the actuator vanes or switch.

Abstract: A pivoting armature which functions as part of an electric control motor is rotatably supported on a shaft in a housing of the electric control motor and has a pole carrier on which pole shoes are mounted, the pole shoes being joined to the pole carrier in a rotationally fixed manner. The pole shoes can be produced by sintering or welding on a pole shoe ring that is pressed onto the pole carrier, or by stacks of laminates.

Abstract: A disk-shaped and coreless type electric motor for controlling the tilt of a throttle valve. The motor includes a field magnet having at least one pair of N and S poles and a stator armature having at least one set of coils disposed in face-to-face confronting relation to the magnet. The shaft of the motor is coupled directly to the shaft carrying the throttle valve, the latter shaft being urged by a spring toward a position where the valve throttles off the passage of air. The coil is so positioned relatively to the N and S poles of the magnet that when the coil is excited, any conductor portions thereof can act effectively to develop torque to rotate the magnet.

Abstract: A rotary driving device includes a pair of stator magnetic poles having opposing end faces separated by gaps; a rotor of magnetic material rotatably supported inside the stator magnetic pole pair, having two pole surfaces between two planes parallel with the axis of rotation; and an excitation coil of the stator magnetic pole pair. The angular positions of the gaps between the end faces of the stator magnetic pole pair along the circumferential direction are changed along the axial direction, so that output and detent torques are obtained effectively and satisfactorily.

Abstract: A rotary actuator has a casing; a rotor rotatably provided in the casing; an exciting coil mounted on the rotor; a magnetic pole member provided in the casing which surrounds the rotor; first, second and third contact elements mounted on the rotor and electrically coupled to opposite end terminals and an intermediate terminal of the coil respectively; first and second stops provided in the casing and cooperating with the rotor to restrict the rotation thereof over a predetermined angular range; fourth, fifth and sixth contact elements mounted on the casing to cooperate respectively with the first, second and third contact elements such that the sixth contact element permanently contacts the third contact element, that the fourth contact element contacts the first contact element except when the rotor engages and is adjacent to the first stop and that the fifth contact element contacts the second contact element except when the rotor engages and is adjacent to the second stop; and a switch for applying electri

Abstract: A non-continuous brush and commutator segment torquer motor having a single radial air gap. The motor can be placed on the opposite side of the gimbal center line of a payload. This arrangement minimizes torquer mass, as well as providing greater clearance for the gimbal payload to travel through larger angular excursions. Hence, all payloads which are gimbal mounted, such as radar antennas, can be located closer to the gimbal center and can be driven through larger look angles.

Abstract: An electromagnetic rotary driving device including a rotor of a permanent magnet arranged in a hole formed in a bored stator core block of a stator core, made from magnetic material. The air gap formed between the bored block of the stator core and the rotor in the direction parallel with the magnetic path in the stator core is relatively long, while the air gap formed between the bored block of the stator core and the rotor in the direction perpendicular to the magnetic path in the stator core is relatively short. In this device, the angle of rotation of the rotor is continuously changed by the current flowing through the coil of the stator without requiring a spring for return motion.

Abstract: A rotary drive apparatus includes: a bar yoke, a coil mounted on the bar yoke, and a cylindrical case, having a magnetic property for receiving the coil and the bar yoke therein. The cylindrical case has at least one salient-pole portion formed on the inside thereof in the vicinity of a portion where the coil is received. The rotary drive apparatus also includes a rotary member facing the salient-pole portion and spaced from the bar yoke and the salient-pole portion by a predetermined gap, so that the rotary member rotates between the bar yoke and the salient-pole portion, and is provided with at least one magnet having opposite magnetic polarities and arranged along the circumference of the rotary member and facing the salient-pole portion. The salient-pole portion, the magnet, and an end-of-the-yoke member form a magnetic circuit. The rotary member is rotated in response to magnetic flux generated at the end of the bar yoke by applying an electric current to the coil.

Abstract: A noiseless rotary detent switch, wherein a ferromagnetic projection passes in close proximity to a magnetic pole, in combination with a first photoelectric detector for detecting the leading and trailing edges of said projection and a second photoelectric detector for detecting the presence or absence of said projection, the magnetic attraction between said projection and said pole providing the noiseless detent action and said first and said second photoelectric detectors providing electric signals for actuating switches in a sequence corresponding to that of the direction of rotation of said rotary switch.

Abstract: An electromagnetic position control apparatus including a rotary sphere having a permanent magnet. The rotary sphere is rotably supported within a spherical hole formed at a crossing portion of a cross-shaped yoke. Coils are used to create magnetic fields at the rotary sphere. The position of rotation of the rotary sphere is controlled in three dimensions by means of changing the intensity of the direct current supplied to the coils or the duty cycle of the pulse current supplied to the coils to change the intensity of the magnetic fields.

Abstract: Generally speaking, the present invention relates to an electromagnetic valve for subsea applications. It comprises a valve body, a rotatable core (with an aperture) located within the valve body (it may be shaped like a plug or a ball), a means for creating a magnetic field located between the valve body and the core and electrically conductive windings wrapped around the rotatable core. The windings are connected to a source of DC power and when energized they cause the core to rotate in one direction or the other depending on the polarity of the DC current.

Abstract: An electromagnetic positioner for positioning the drive arm of a servovalve or the like, comprising an armature extending between laterally spaced pairs of vertically disposed and vertically spaced coils for pivotal movement in a plane which includes the axes of said coils, a drive arm assembly comprising a flexure tube secured to the base or lower pole of the positioner, and extending upwardly to a position above the level of the armature, and an adapter secured at its lower end to the armature and its upper end to the upper ends of the flexure tube and drive arm so that the pivot point of the armature is adjacent but above the center of rotation of the drive arm. Also provided is a null adjusting arrangement in which the driven parts are located partly in the body of the positioner and partly in the body of the pilot valve, thereby freeing space in the positioner and reducing the height thereof.

Abstract: A rotary driving apparatus suitable for use for a flow control valve provided with a rotor valve rotatably mounted in a housing. The rotor valve is connected to a permanent magnet member. The permanent magnet member is arranged adjacent to a pair of diametrically spaced ends of a core on which a coil is wound so that the ends are oppositely magnetized to provide a two pole electric motor, stopper means is provided for allowing limited rotary motion of the rotor between a first position and a second position. The permanent magnet member is so arranged with respect to the ends of the core that a torque is, during the de-energization of the coil, generated in order to engage the stopper means. Thus, the first or second position of the rotor valve is maintained without energization of the coil.

Abstract: An electric control motor and a method of making the same are proposed for the driving of a control element. The electric control motor comprises a housing made from a ferromagnetic material, a housing enclosure and a cap, a shaft rotatably disposed therein on which an armature is disposed for association with arcuate poles provided in the housing. An electromagnetic coil comprising coil portions is mounted axially with respect to the armature in coil retainers encapsulating the armature and shaft as a unit for ease of assembly in the housing.

Abstract: A two pole stationary coil rotary magnet motor which provides for increased work and reduced rotary inertia. The motor consists of two main assemblies, a rotor assembly contained within a rotor casing and a stator and housing assembly surrounding the rotor casing. One end of the casing is closed, whereas the other end is open to eliminate the need for a dynamic shaft seal. Fluid enters the casing at the open end thereof to provide a lubricating fluid for the rotor bearings and a heat conductive path. The rotor casing isolates the critical movement of the rotor from the contaminated atmosphere of the stator environment and allows replacement of the stator assembly without disturbing the rotor assembly. A permanent magnet rotor may be formed using one or more rare earth magnets which may be suitably bonded to the rotor shaft. A protective cover surrounds the rotor magnets to eliminate potential rotor magnet breakage contamination.

Abstract: In an actuator having a stator assembly which defines a pair of stator pole faces, a permeable rotor assembly which is positioned to rotate relative to the stator assembly, and which defines a driving pole face separated from each of the stator pole faces by a flux permeable driving gap, the rotor assembly having an operational range of rotor angular positions over which drive flux passing across the driving gap drives the rotor assembly, the extent of the driving gap at one of the stator pole faces being reduced as the rotor assembly rotates toward the limit of the operational range, the improvement including a flux-permeable compensating gap between the driving pole face and each stator pole face which provides a secondary path for drive flux as the rotor assembly rotates toward the limit of the operational range, the compensating gap being less permeable than the driving gap.

Abstract: A driver for rotating a magnetic head affixed thereto having a housing, an armature rotably mounted within the housing, at least two field magnets within the housing and positioned around the axis of rotation for the armature, a driving coil and a concentrator for concentrating the magnetic flux from the field magnets so as to return the armature to a home position when no current is applied to the driving coil. The driver is affixed in the housing concentric with at least a portion of the armature such that a current passing through the driving coil develops a magnetic field polarizing the armature and causing a peripherential attraction of the armature toward an adjacent one of the field magnets and a corresponding repulsion of the armature from an adjacent other of the field magnets, thereby tending to rotate the armature a direction and distance proportional to the magnitude and polarity of the current.

Abstract: A bistable electromagnetic latch, particularly adapted for use with an electronic combination lock on a luggage case, comprises a magnetic member pivotally mounted for rotation between a pair of pole pieces, the magnetic member having first and second stable rotational positions at which each magnetic pole is adjacent to a different pole piece, and a pair of oppositely wound coils associated with the pole pieces and responsive to the momentary flow of electrical current therethrough for producing a magnetic flux that causes the magnetic member to rotate from one position to the other.

Abstract: An electrical force motor, suitable for use in electro-hydraulic servo valves, has a circular permanent magnet which is polarized across its diameter, which is disposed at least partly within one of the pole pieces of the motor and which is rotatable with respect to that pole piece to increase the effective strength of one pole of that pole piece and to decrease the effective strength of the other pole thereof.

Abstract: An electromagnetic actuator for performing an individual stepping, switch or impact movement consists of an electromagnetic actuator and a pivoted or rocking armature moving. The rotational design of the electromagnetic actuator enables only one excitation coil to serve a plurality of magnetic gaps.

Abstract: Motor includes an internal torsion spring which provides for null centering of the rotor assembly while minimizing bearing load reactions and related friction. Two such centering springs may be provided whereby in the event one spring should fail, the other spring will still be operative to perform the desired null centering function. Also, an internal leaf spring interiorly of the rotor casing absorbs the full stroke rotor inertia without part damage or deformation. The null position bias of a motor driven valve may be established by adjustment of a pair of set screws which adjust the rotor assembly off null without inducing undesirable friction. The stator electrical torque null of the motor may also be set by providing an adjustable eccentric pin in the stator housing which is engageable in a notch in the rotor casing.

Abstract: An adjusting device for precise rotary angle adjustment of final control elements in closed- or open-loop control devices. The adjusting device comprises a rotary magnet apparatus in which parallel air gaps are formed between the poles of the armature and the magnet poles of the armature counterpart. In order to attain constant torques over the angle of rotation of the armature, when the electric current applied to the coil is constant, the end faces of the armature poles are embodied as wedge-shaped.

Abstract: A rotary solenoid actuator for proportionally controlling the flow of fluid, such as air, in a pipe comprises a housing with a rotor rotatably mounted thereon. A stationary coreless coil for generating a magnetic field in response to a control current therethrough is mounted in the housing. A permanent magnet is affixed to a rotatably mounted shaft within the coil, and a return spring is attached to the rotating shaft. Due to low hysteresis in the coreless coil, there is a linear relationship between the control current and the fluid flow.

Abstract: A rotary actuator for driving a fluid control valve comprises a yoke which forms a closed magnetic path an excitation coil which produces a magnetic flux in the yoke, a permanent magnet which is rotatably arranged in a through hole or in a slit formed in the yoke, and a restoring spring which produces a force acting against a rotational torque generated in the magnet by a main magnetic flux which flows through the yoke and the permanent magnet when the excitation coils is energized. Shielding portions are formed on both sides of the ends of the yoke, which ends oppose the permanent magnet, so as to substantially shield the permanent magnet together with the ends of the yoke, whereby a magnetic reluctance of a path of the magnetic flux remains substantially constant irrespective of the rotating position of the permanent magnet with respect to the yoke when the excitation coil is de-energized.

Abstract: A rotor of a high-speed electric machine comprises a shaft 1, a magnetic ring 2 enclosing the shaft 1, a retaining ring 3, and permanent magnets 6 sisposed between the retaining ring 3 and the magnetic ring 2. The retaining ring 3 is secured to the shaft 1 by couplers, and a clearance 7 is provided between the permanent magnets 6 attached to the inside surface 5 of the retaining ring 3 and the magnetic ring 2.

Abstract: A limited-rotation actuator in which the rotor pole faces and corresponding stator pole faces are spaced apart along the axis of rotation, the rotor pole faces are permeably connected by a flux path having an axial component through the rotor, and the rotor and stator pole faces each subtend an angle of between about 90.degree. and about 180.degree. around the axis. The invention enables wide angle excursions of the rotor and inexpensive fabrication.

Abstract: An actuator has a rotor with permanently magnetized North and South poles. A housing supports three pole members having respective coils and pole pieces. The first pole piece is always a North pole but the coils on the second and third pole pieces are arranged such that each can be of either polarity with the other simultaneously being of the opposite polarity. The rotor therefore has two stable positions, one when the second pole piece is a North pole and the third pole piece is a South pole and the other being 120.degree. from this position in the clockwise direction (when the second pole piece is a South pole and the third pole piece is a North pole). The rotor movement may however be stopped 15.degree. short of each such position by mechanical detents, so as to limit the maximum angular movement to 90.degree.. The actuator may be used to drive a switchable microwave coupling arrangement.