Abstract: A magnetic field core and armature core are provided on a rotor in spaced-apart relation to each other. Windings for producing rotating magnetic poles are positioned on the magnetic field core, and armature windings are positioned on the armature core. The rotor includes a plurality of magnetic sections which are magnetically coupled with the magnetic field core and armature core, but the magnetic sections are magnetically separated from each other in a direction of rotation of the rotating magnetic poles. Magnetic poles produced on the rotor will be coupled together through a magnetic path formed by the rotor and armature core. Thus, by passing three-phase alternating currents, corresponding to the magnetic poles produced on the rotor, through the armature windings, torque is developed in accordance with the Fleming's rule, so that the rotor is caused to rotate as a motor at a synchronous speed.

Abstract: To prevent a ball-threaded shaft from slipping out of a linear actuator, a linear actuator 10 has an output shaft 18 threaded in a nut 16 for moving forward and backward linearly with respect to an outer tube 22 secured to a housing 20. Linear reciprocating movement of the nut 16 is effected by a ball-threaded shaft 14 rotated normally and reversely by a driving motor 12. The shaft is held against axial displacement by a bearing assembly 8 having an axial disk 32 secured to a proximal end 24 of the ball-threaded shaft 14. On the nut side of the disk within the assembly are disposed a first tension receiving rotational body 36, a thrust bearing 45 and a second tension receiving rotational body 58. The assembly 8 is retained by a tension stopper 62 spread and inserted into an annular central groove 60 in the tube 22.

Abstract: A contactor for a motor vehicle starter comprises a contactor coil, a movable contactor core actuated by a control rod, and a fixed contactor core. It also has an electromagnetic auxiliary control relay which includes a movable relay core carrying a movable contact ring which is arranged for cooperation with at least one pair of fixed relay contacts, carried by a fixed annular contact carrier plate. The relay coil, the contact carrier plate, and the movable contact ring are arranged in axial succession, in that order towards the front of the contactor, and are disposed between the movable contact of the contactor and the fixed core, so that the relay and the contactor are closed in the same, forward, direction.

Abstract: A vibration actuator for effecting paging is provided in which a vibrating section of an electroacoustic transducer is driven using low frequencies to collide it against a fixed section, and the vibration generated from the collision is transferred as external vibration. The vibrating section of a coil and the fixed section are bonded via an elastic member provided therebetween. The vibration generated at the time of collision can be effectively increased by flexibly supporting a magnetic circuit composed of a magnet, a yoke, etc. and by driving the magnetic circuit with alternating current which has a polarity. To permit easier assembly and to prevent damage or deterioration in characteristics, it is preferable to provide an annular molded member, which has hook-like projections, around the magnetic circuit and to support the magnetic circuit by a rubber member attached to the hook-like projections.

Abstract: A spring motor utilizes a series arrangement of alternately-wound coiled springs coupled to one another at common ends. The spring motor is coupled to a generator through a gear mechanism to provide a portable and reusable supply of electric power. In addition, the spring motor may be used in a vehicle to recapture wasted energy due to lost momentum during braking. The spring motor is coupled to a winding mechanism for driving the spring motor in response to application of the vehicle's brakes.

Abstract: A disk drive actuator assembly adapted for assembly in one of several configurations from a single line of modular components without a manually-supervised aligning step. The actuator improves manufacturability and inertia by introducing a common set of self-aligning modular piece parts. Each of several self-aligning modular components can be used to assemble any of several different actuator assembly designs. That is, a head-stack assembly (HSA) providing from one to six heads can be assembled using elements selected from single set of standardized modular components. The assembly process relies entirely on the self-aligning features of the standardized modular components, thereby eliminating the elaborate and error-prone manual assembly and alignment procedures known in the art.

Abstract: A magnetic circuit structure in a disk unit which can be manufactured at low costs. The magnetic circuit includes a main yoke manufactured by stacking a plurality of rolled steel plates and connecting them together by caulking. The magnetic circuit further includes an inner magnet, an outer magnet, and a side yoke all of which are mounted on the main yoke. Both ends of the inner magnet abut against a pair of shoulders formed on the main yoke, and both ends of the outer magnet abut against a pair of shoulders formed on the main yoke. Vertical movement of the inner magnet is prevented by a pair of presser plates and fixed to the main yoke, and vertical movement of the outer magnet is also prevented by a pair of presser plates and fixed to the main yoke.

Abstract: An improved cylindrical linear motor is capable of being more easily assembled by changing the constructions of a primary iron core and a primary coil and significantly preventing an over-heating of the primary coil. The motor includes primary toothed sections formed of stacked steel plates, with the primary toothed sections being spaced-apart from one another, a supporting member formed to support the primary toothed sections, coils wound onto the supporting member and between the primary toothed sections, a yoke formed of stacked steel plates and engaged to the primary toothed sections between which the coils are wound, and a secondary iron core inserted within the primary iron cores.

Abstract: A modular planar motor having (a) a mounting plate which has (i) a plurality of openings therein each having an interior surface, (ii) a housing, (iii) a surrounding ridge, and (iv) an undersurface, (b) a superstructure over the mounting plate, and (c) a plurality of modular components each disposed within the openings and having a covering hood for the components, and (d) an aligning and gluing gap between the modular components and the mounting plate and being filled with an adhesive composition for bonding the modular components to the mounting plate.

Abstract: In the linear motor including (a) a plurality of permanent magnet members 1 fixed to a pair of ferromagnetic yokes 3 such that longitudinally adjacent magnetic poles have different polarities and that the magnetic poles of different polarities face each other via a magnetic gap 7, (b) a polyphase coil 2 disposed in the magnetic gap 7, either one of the polyphase coil 2 and the permanent magnet members 1 being caused to move relative to each other when the polyphase coil 2 is energized; and (c) a coil-supporting member 4 to which the polyphase coil 2 is fixed, the coil-supporting member 4 is made of non-magnetic ceramics having excellent heat conductivity and insulation.

Abstract: A linear motor device includes a primary linear motor member and a secondary linear motor member shaped of teeth of a comb with a plurality of projecting portions arranged at predetermined intervals. Recesses defined between the projecting portions are filled up with filler members for flattening a surface of the secondary linear motor member facing the primary linear motor member. Therefore, it is possible to remove chips from the surface easily. Since the filler members are made of low magnetical permeability material, the magnetic shielding between the neighboring projecting portion can be maintained. A linear motor device for a machine tool includes a bar type secondary linear motor member having both ends supported by an immovable member of the machine tool and a cylindrical primary linear motor member attached to a movable member of the machine tool.

Abstract: An electromagnetic linear drive has a stationary unit, a mobile unit centered and coaxially placed with respect to the stationary unit and an enclosing assembly made of diamagnetic material to support and protect the stationary unit and the mobile unit. The stationary unit contains a coil, wound around a bobbin made of non-conductive and diamagnetic material including a stationary magnet coaxially attached to the lateral face of the bobbin. The mobile unit includes a mobile magnet fastened to a shaft made of diamagnetic material which holds, positions and further transfer the linear motion of the mobile magnet to the driven device. Two stationary units are used to obtain controlled movement in both direction. The permanent magnets are magnetized in the direction of their thickness, coaxially positioned and arranged to repulse each other. The coils are connected in series with the magnetic fields opposed.

Abstract: A linear voice coil actuator using a removable electromagnetic coil includes an electrically conductive wire wound on a plastic bobbin. The wire which is wrapped around the bobbin is connected to an external power source as the electromagnetic coil is attached to the linear voice coil actuator. Current applied from the external power source causes the electromagnetic coil to selectively generate a magnetic field and, in response to generation of the magnetic field, to move translationally within a fixed magnetic field. The translational movement of the coil moves a grip which is mounted on the coil to allow the grip to selectively position and manipulate objects and things.

Abstract: A passive magnetic bearing structure for radially supporting a rotor with respect to a stator is provided, in which a magnetic circuit is mounted on the rotor or stator for generating two strongly different axial magnetic fields in two concentric angular gaps coaxial to the rotation axis and radially spaced from one another. At least three shortened superconducting turns are mounted on the stator circumferentially around the rotation axis so that under any tolerable shift of the rotor, one edge of every turn will be placed in one annular gap comprising magnetic field, and the radially opposite edge will be placed in the other gap.

Abstract: A voice coil motor has a flux return housing with at least one magnet and a soft iron cantilevered core. A coil holder, including an electrical coil spaced from magnet, is telescoped over the core with an air gap between the sides of the coil holder and the sides of core. The coil holder has an open end and a closed end forming with the distal end of the core a pressurized air bellows, which can vertically support a payload such as a Z-axis motion stage. The coil holder is telescopically movable with respect to the core along the air gap supplied with pressurized air through longitudinal air ducts in the core and through transverse orifices extending from the ducts to the air gap. A regulator is connected to a core central bore for adjusting pressure in a bellows chamber between the coil holder closed end and the distal end of the core for supporting the payload.

Abstract: An X-Y positioning machine has a forcer, with armature coils, that moves around on a platen, supported by an air bearing. Magnets embedded in the motor platen generate a fixed magnetic field with which the armature coils interact. Perpendicular elongated coils interact with the fields of magnets in columns and rows. When a traditional rectangular pattern of the magnets is provided, a packing density and average peak magnetic flux intercepted by the coils are limited to 50%. The present invention provides magnet configurations that provide greater than 50% maximum peak flux density and up to 100% packing density. Several magnet arrangements are provided: a first in which round magnets are used instead of square, and a second in which diamond-shaped magnets are used. The latter can be used at 100% packing density arrangement. In addition to high peak flux density for a narrow coil, these embodiments exhibit low cogging forces. A method of making the magnet is also provided.

Abstract: The precision table has at least one linear drive for the displacement of a cover plate relative to a baseplate for motion in at least one coordinate axis, wherein the linear drive has at least one magnet and at least one coil. The resultant displacement force acts in the center of the plate that is to be moved.

Abstract: A structure for a compression driver motor assembly which utilizes a pot with an integral top plate and a pole cap, thereby reducing magnetic losses and permitting manufacture of a driver structure with fewer parts and reduced weight. A more efficient process for manufacture of the motor assembly is also disclosed. The pot is manufactured with an integral top plate which is adapted for use with a large pole cap. The pole cap is affixed to the top of a permanent magnet and forms the magnetic gap with the top of the pot. The magnetic circuit of the driver thus includes a permanent magnet, a pot, a magnetic gap and the pole cap. The motor assembly is assembled in a process requiring fewer steps and less elaborate tooling than the motor assembly of the prior art.

Abstract: A ferromagnetic member (21) of a movable part (2) is disposed on a side of a stationary part (1) such that the ferromagnetic member (21) faces a high temperature superconductor (11) of the stationary part (1). The high temperature superconductor (11) is brought into a superconductive state by cooling it to a temperature below a critical temperature in a magnetic field. The magnetic flux pinned to the high temperature superconductor (11) is caused to pass through the ferromagnetic member (21) so that an attractive force is generated between the high temperature superconductor (11) and the ferromagnetic member (21) to hold the movable part (2). When the ferromagnetic member (21) has a shape such that when the gap becomes lower than a predetermined value, the attractive force decreases, the movable part (2) can be stably suspended in a non-contacting manner, without the necessity of control, by the combination of the high temperature superconductor (11) and the ferromagnetic member (21).

Abstract: A magnetic circuit structure in a rotary actuator which can reduce the inductance of a coil while negligibly reducing a magnetic flux density between gaps. The magnetic circuit structure includes an E-shaped main yoke formed by integrally connecting a curved inner yoke, a curved center yoke, and a curved outer yoke. The E-shaped main yoke is manufactured by stacking a plurality of rolled steel plates. An inner magnet is mounted on the outer circumferential surface of the inner yoke opposed to the center yoke, and an outer magnet is mounted on the inner circumferential surface of the outer yoke opposed to the center yoke. A side yoke is magnetically attached to the open end of the E-shaped main yoke. A through hole extending in parallel to the axis of rotation of the rotary actuator is formed at a circumferential central portion of the center yoke.

Abstract: A linear motor (220) suitable for use with a cryogenic cooler is described. The arrangement comprises first and second annular magnets (100 and 110), which in the preferred embodiment are nested and share a common axis. A circular bore (190) is defined about the common axis and is able to receive a drive shaft (220). The drive shaft (220) is connected to a base member (210) which has an annular peripheral region (200) in which a coil (200) is defined. Coil (200) has poles (150 and 160). The coil (200) when energised causes reciprocal motion of the drive shaft (220). The coil (200) per se is able to move into and out of an annular cavity (170) defined between the nested magnets (100 and 110).

Abstract: The arm assembly includes an arm member composed of a rotatable boss member; three or more arm plates each formed from a thin, non-magnetic metal sheet and extending in parallel from one side of the boss member; a coil member fixed to the other side of the boss member such that the coil member is swingable in a magnetic gap; and a suspension member having a front end equipped with a recording/reproducing head and a rear end fixed o a free end of each arm plate; wherein pins projecting from upper and lower surfaces of the boss member are fitted into through-holes of an uppermost arm plate and a lowermost arm plate so that the uppermost and lowermost arm plates are strongly fixed to the boss member, and wherein at least one arm plate disposed between the uppermost and lowermost arm plates is integrally fixed to the boss member with a thermoplastic resin.

Abstract: To improve a machine tool, comprising a machine frame, a workpiece holder arranged on the machine frame for a workpiece to be machined, a tool holder arranged on the machine frame for receiving a tool and at least one drive with a slide for executing a relative movement between the tool and the workpiece in the direction of at least one axis, such that it allows as high dynamics as possible, it is proposed that the drive comprise electric linear motors aligned parallel to the axis and spaced from one another in a transverse direction, that the slide extend between the two linear motors, and that a control be provided for simultaneously operating the linear motors for displacement of the slide.

Abstract: The door or doors on an elevator cab are driven during their opening and closing cycles by a linear induction motor drive system. The primary of the linear motor is fixed to the cab assembly, and the secondary is mounted on the door hanger panel and moves with the door. In order for the secondary to maintain a proper spacing relative to the primary, a flexible connection is provided between the secondary and the remainder of the door. In this way, shifting of the door during its opening and closing movements will not cause misalignment of the secondary with respect to the primary.

Abstract: An electromagnetic actuator includes an actuator rod having a plurality of magnetic assemblies disposed about a longitudinal axis of the actuator rod. Each plurality of magnetic assemblies develops alternating magnetic flux along the longitudinal axis. The electromagnetic actuator further includes a plurality of stator windings secured to a support structure and disposed about the longitudinal axis. Each stator winding has a pole facing a portion of one of the plurality of magnetic assemblies and the longitudinal axis.

Abstract: A voice coil motor (VCM) for a small form factor hard disk drive having a contoured flux field in the air gap wherein adjoining regions of oppositely directed magnetic flux form a transition zone. In the preferred embodiment, the magnetic structure assembly is contoured or shaped. The magnetic structure assembly comprises pole pieces and magnets. The shaping may be of either of the pole pieces or of either of the magnets. The shaping may be along the top edge only, along the bottom edge only, or along both edges. Alternatively, the shaping may be accomplished in the transverse plane, that is by shaping the profile in thickness. The shaping can be done so that when the flux is falling in one gap it is rising in the other gap. In this manner, the sum of the flux in the two gaps remains the same.

Abstract: A swing-type actuator (10) includes a coil (20), at least one arm (40) and a thermoplastic body (50) joining the coil (20) and arm (40). The arm (40) is preferably a planar stamping having an opening (43) to which the read/write head is mounted. A body (50) is molded around portions of the arm (40) and coil (20). A journal (52) is formed in the body (50) for receiving a shaft and bearing on which the actuator (10) pivots. A grounding pin (40B) extending through the arm (40) prevents static charge build-up. Alternatively, a portion of the arm (40) may extend into the journal (50) to contact the a bearing. In another embodiment, the arm (140) includes a plastic portion (70) and a metal mounting pad (80). The plastic portion (70) may be formed of electrically conductive material to prevent static charge buildup.

Abstract: An electric generator for generating an electrical current that comprises a continuous housing containing equally spaced-apart magnets that pass the continuous housing through the center of a plurality of individual coils in a concentric larger outer housing. To enhance the current generated, a plate is inserted between adjacent coils in the larger housing and the magnets are arranged so that opposite poles are adjacent each other. To further increase current generation, the coils may be cooled so as to reduce any resistance therein.

Abstract: A reciprocating magnetic body support structure for a linear motor or a linear alternator is claimed. The body comprises a cylindrical, metallic support sleeve having a plurality of longitudinal slots evenly spaced around the circumference of the sleeve. An equal number of magnet segments is mounted to the sleeve extending over at least a portion of the associated slot and attaching to the wall of the sleeve on both sides of the associated slot. The longitudinal slots preferably extend completely through the sleeve from near one longitudinal end of the sleeve to near an opposite longitudinal end of the sleeve. The sleeve is preferably stainless steel or titanium, but should, regardless of metal, have a high resistivity, i.e., above 50 micro ohms per centimeter.

Abstract: A moving coil linear actuator including an elongated permanent magnet having a cross-sectional width substantially greater than its edge height and having an elongated length of soft magnetic material disposed along one or both edges of the permanent magnet to enhance the magnetic field strength in the gap through which the moving coil translates.

Abstract: A device providing an accurate adjustment of the length of a reciprocating stroke of an actuating rod of a linear actuator. The stroke control device includes a cam-plate mounting shaft 9 horizontally disposed within a limit switch box so that a plurality of limit-switch actuating cam plates 11A-11C mounted on the mounting shaft 9 for actuation of a corresponding number of limit switches LA-LC to control the stroke length of the actuating rod can be observed in one view as a horizontal array of laterally spaced, vertically disposed cam plates.

Abstract: In one embodiment, a device for detecting the position of a head attached to a linear motor, the detection device comprises an extension member for guiding and directing flux therein. A moving coil disposed on the extension member which coil, when energized, moves along the extension for positioning the head. A magnet positioned in a spaced apart relationship with the coil for inducing a drive flux which assists in imparting the motion to the coil when the coil is energized. A first wall is positioned adjacent the linear motor. A second wall is positioned in a spaced apart relationship with the first wall.

Abstract: An electromagnetic actuator (1) comprises two actuator sections which are translatable relative to one another along an actuator axis (1a) and which are rotatable about the actuator axis, a first actuator section (1) comprising a coil system and a second actuator section (3) comprising a permanent magnet system for cooperation with the coil system via an air gap. The coil system is arranged on a magnetically conductive yoke (5) and comprises a cylindrical translation coil (9) and a toroidal rotation coil (7), which are coaxial with the actuator axis. The permanent magnet system comprises an annular magnet (11), which is coaxial with the actuator axis, for cooperation with both the translation coil and the rotation coil. The magnet has a radial magnetisation (B) which is interrupted by an annular segment (13). The magnetically conductive yoke has a central core (5b) around which the translation coil is arranged and a shell (5a) on which the rotation coil is disposed.

Abstract: A one-piece magnet return path assembly for a disk drive actuator comprises an upper plate, a lower plate and a plurality of standoffs extending between the upper and lower plates and establishing a pre-determined spacing between the plates. The upper and lower plates and the plurality of standoffs are stamped from a single sheet of magnetically permeable material that is then bent at predetermined locations to form the completed one-piece magnet return path assembly.

Abstract: A movable coil-type actuator including (a) a permanent magnet assembly constituted by a flat permanent magnet and a lower yoke element made of ferromagnetic material, the permanent magnet assembly including a recess in a central portion; (b) an upper yoke element made of a ferromagnetic material, the upper yoke element having such a shape that an edge of the permanent magnet does not extend from a periphery of the upper yoke element when viewed from above; (c) a unitary base member made of a thermoplastic resin and integrally including a hold portion for receiving the permanent magnet assembly and support portions for supporting the upper yoke element, a magnetic gap being defined by the permanent magnet and the upper yoke element; and (d) a movable coil fixed to an end of a swingable arm and movable in the magnetic gap.

Abstract: A swing-type actuator having: (a) an upper yoke made of a ferromagnetic material, (b) a permanent magnet assembly constituted by a lower yoke made of a ferromagnetic material and opposing the upper yoke and a flat permanent magnet attached to the lower yoke; (c) a base member made of a thermoplastic resin and having a hold portion projecting from an upper surface of the base member for defining a space into which the permanent magnet assembly is received and support portions projecting from an upper surface of the base member for fixing the upper yoke such that there is a magnetic gap between the permanent magnet assembly and the upper yoke, the base member being integrally molded together with the permanent magnet assembly such that the permanent magnet assembly is fixed to the base member inside the hold portion; and (d) a swingable arm having one end adapted to receive a movable coil and the other end to which a function member is fixable, the movable coil being swingable in the magnetic gap.

Abstract: According to the electromagnetic driving device of the present invention, since it has a fixed member having an outside yoke and an inside yoke, a magnet for generating the thrust being bonded on either side of the outside yoke or inside yoke, and a movable member having a driven holding body portion for holding a body to be driven, and a coil wound in more than two phases in an axial direction between said outside yoke and inside yoke, and is movable in an axial direction with respect to the fixed member, in which a body to be detected is provided in said movable member, and a position-detecting element is provided in the fixed member which detects the magnetic field of said magnet and detects the position of the movable member to generate a position-detecting signal for controlling the current supply to the coil, any restrictions of the moving range and any decrease in the moving speed due to wiring and the like of the movable member are not caused, and smooth movements according to the current supply to th

Abstract: A novel voice coil actuator is disclosed having a magnetic flux conductive material core, an axially focused, radially oriented magnet structure, and an electrical current conductive coil. The core has a first surface and a continuous channel disposed in the first surface. The channel has a first wall and a second opposing wall, the first wall defining a recess. The magnet structure is disposed in the recess of the first wall and spaced from the second wall so that a gap remains between the magnet structure and the second wall. The magnet structure includes a first radially polarized magnet having an axially extending surface defining an upper edge and a lower edge, a second axially polarized magnet having a second magnet radially extending surface extending radially inward from the first magnet upper edge, and a third axially polarized magnet having a third magnet radially extending surface extending radially inward from the first magnet lower edge.

Abstract: A voice coil actuator includes a magnetic flux conductive material core, a magnet and an electrical current conductive coil. The core has a first surface and a continuous channel disposed in said first surface. The channel has a pair of opposing walls. The magnet is disposed in intimate contact with a first one of said walls and spaced from a second one of said walls so that a gap remains between the magnet and the second one of the walls. The magnet has a first face of a first magnetic polarity facing the first one of the walls and a second face of a second, opposite magnetic polarity facing the gap. The magnet is further spaced from a bottom of the channel so that magnetic flux is substantially normal from the second face across said gap to the second one of the walls.

Abstract: A device for locating terminal pins relative to a swing-type actuator coil includes a body, a pair of terminal pin sleeves and a bridge member joining the body and the sleeves. The body has an outer circumference less than the inner circumference of the coil, so as to allow the body to be press-fit within the coil. The body has a thickness less than the thickness of the coil. The body has an opening for locating the device in a mold while joining the body and coil to an actuator arm by injection molding a hold member about a portion of the coil, device and arm. The body further includes features for preventing the device from assuming a skewed orientation in the mold. The thickness of the projections is equal to the difference in thickness between the body and the coil. During the molding process, a portion of the hold member is formed adjacent the body on the interior of the coil and is flush with the projections. In this manner, the coil is secured to the body and the arm.

Abstract: An electromagnetic actuator for moving a focusing lens along an optical axis includes a lens barrel having two supporting rails, a set of cylindrical inner and outer yokes incorporating a pair of magnets, a lens holder which holds the lens and is supported slidably on the supporting rails by means of a bearing device and rail guide provided on two arms of the lens holder, a coil wound on a bobbin which is fixed on the lens holder and located so that the coil is exposed to the magnetic field of the magnets inside the yokes. The yokes have cut portions, allowing the arms of lens holder to cut into the yokes when the lens is moved.

Abstract: A linear accelerator has at least one longitudinal stator section that defines a linear path of movement and that comprises several stator coils as well as a rotor with several rotor coils that can be accelerated along the path of movement. The stator is designed as a tubular body from the inner wall of which project coil carriers with coil conductors that are mutually offset by 90 degrees. The cavities thus formed are engaged by the rotor coils that comprise each an electrically non-conductive carrier on the sides on which are arranged meandering coil conductors. The design and arrangement of the rotor coils and stator coils allow a circular magnetic field to be generated, with the result that the rotor is axially accelerated. The rotor is supplied with current by conductor rails by a cable entrained with the rotor an/or by charge accumulation in the coils before acceleration begins.

Abstract: A voice coil motor (VCM) for a small form factor hard disk drive having a contoured flux field in the air gap wherein adjoining regions of oppositely directed magnetic flux form a transition zone. In the preferred embodiment, the magnetic structure assembly is contoured or shaped. The magnetic structure assembly comprises pole pieces and magnets. The shaping may be of either of the pole pieces or of either of the magnets. The shaping may be along the top edge only, along the bottom edge only, or along both edges. Alternatively, the shaping may be accomplished in the transverse plane, that is by shaping the profile in thickness. The shaping can be done so that when the flux is falling in one gap it is rising in the other gap. In this manner, the sum of the flux in the two gaps remains the same.

Abstract: A swing-type actuator having: (a) an upper yoke made of a ferromagnetic material, (b) a permanent magnet assembly constituted by a lower yoke made of a ferromagnetic material and opposing the upper yoke and a flat permanent magnet attached to the lower yoke; (c) a base member made of a thermoplastic resin and having a hold portion projecting from an upper surface of the base member for defining a space into which the permanent magnet assembly is received and support portions projecting from an upper surface of the base member for fixing the upper yoke such that there is a magnetic gap between the permanent magnet assembly and the upper yoke, the base member being integrally molded together with the permanent magnet assembly such that the permanent magnet assembly is fixed to the base member inside the hold portion; and (d) a swingable arm having one end adapted to receive a movable coil and the other end to which a function member is fixable, the movable coil being swingable in the magnetic gap.

Abstract: A voice coil actuator includes a magnetic flux conductive material core, a magnet and an electrical current conductive coil. The core has a first surface and a continuous channel disposed in the first surface. The channel has a pair of opposing walls. The magnet is disposed in intimate contact with a first one of the walls and spaced from a second one of the walls so that a gap remains between the magnet and the second one of the walls. The magnet has a first face of a first magnetic polarity facing the first one of the walls and a second face of a second, opposite magnetic polarity facing the gap. The magnet is further spaced from a bottom of the channel so that magnetic flux is substantially normal from the second face across the gap to the second one of the walls.

Abstract: A linear motor of the type used to control the radial position of a write/read transducer relative to a rotating data storage disk comprises an elongated tubular-shaped permanent magnet which concentrically surrounds and is spaced, by an air gap, from an elongated pole piece of highly permeable material (e.g. steel). A selectively energizable coil, concentrically arranged between the magnet and pole piece, is adapted to move axially in response to an applied current. According to the invention, the pole piece supports a plurality of "shorting rings" made of high conductivity, low permeability material. The shorting rings are embedded in the pole piece so as to be coextensive with the surface thereof. The spaced shorting rings function as a "shorted turn" which operates to reduce the rise time of current applied to the coil without significantly reducing the magnetic flux in the air gap through which the coil is linearly driven.

Abstract: A linear electrodynamic machine is disclosed having non-axisymmetric, interdigitating interfaces between moving and fixed magnetic circuit elements. The moving magnet elements may be of permanent magnet or electromagnetic construction, and in one embodiment constitute low reluctance elements moving relative to fixed energizing and output coils. Magnetic elements on a reciprocating plunger couple to fixed elements of a magnetic circuit in an interdigitating manner. Alternators and motors with non-axisymmetric, interdigitating interfaces are disclosed.

Abstract: A swing-type actuator includes a coil, at least one arm and a thermoplastic body joining the coil and the arm. In one embodiment, the arm is preferably a generally planar aluminum stamping having an opening to which the read/write head may be mounted at one end thereof. A feature is located in the opposite end of the arm to facilitate attachment to the thermoplastic body. The arm also includes at least one flat side perpendicular to its plane at the end including the notch. The body is molded around a portion of the arm and cooperates with the feature to secure the arm thereto. The body also overlaps part of the coil and surrounds the outer circumference thereof. A journal is formed in the body for receiving a shaft on which the actuator pivotally rotates. A grounding pin extending through the arm prevents static charge build-up. Alternatively, a portion of the arm may extend into the journal to contact the bearing.

Abstract: A cylindrically-symmetrical moving coil linear actuator utilizes axially-magnetized cylindrical magnets to provide flux-focused interleaved magnetic circuits. The moving coil linear actuator includes a cylindrical shell that has a closed end and open end. A magnetic core is disposed within the shell to define an annular air gap between the shell and the core. The core includes a first set of axially-magnetized cylindrical permanent magnets having a first direction of magnetization and disposed in proximity to the closed end of the shell. A second set of axially-magnetized cylindrically permanent magnets has a second direction of magnetization which is opposite of the first direction of magnetization and is disposed in proximity to the open end of the shell. A first ferro-magnetic pole piece is disposed between the first set of magnets and the second set of magnets. A second ferro-magnetic pole piece is disposed between the second set of magnets and the open end of the shell.

Abstract: A linear motor having a magnetic circuit and a moving coil, the magnetic circuit comprising a linear yoke provided at the center of the circuit and a pair of linear magnets, the linear yoke and the pair of linear magnets forming a pair of linear gaps with the linear yoke interposed therebetween, the magnetic circuit applying a magnetic field to the linear gaps, the movable coil mounted on the linear yoke of the magnetic circuit being moved along the linear yoke by an electromagnetic action to the magnetic circuit when the movable coil is powered, wherein the linear magnet has a larger magnetic force at opposite end portions in the longitudinal direction of the linear magnet than at an intermediate area, the magnetic reluctance of the magnetic circuit is made large to obtain a driving current of the movable coil corresponding to the magnetic reluctance when the moving coil moves at the intermediate area of the linear magnet, or the magnetic circuit is mounted on a plate made of material having the same magneti