Abstract: An apparatus and method that tests an NMR system, including MRI scanners, by taking H-B measurements for the apparatus at any stage during the manufacture thereof, to thereby detect any defects of the NMR system at any point during the manufacture thereof.

Abstract: A powdered metal electromagnetic is provided that has much less variance between units, increased frictional drag, reduced wear of itself and the brake drum disk during use and an increased resistance to moisture due to the use of a donor material that increases performance and reliability. In addition it can withstand much higher surface speeds while producing higher frictional drag.

Abstract: An automotive emission control valve, an EGR valve in particular, has a solenoid as the actuator for a valve element. The solenoid has a stator and an armature. Various features in construction of the armature and stator pole pieces improve magnetic efficiency to provide increased armature force per unit of solenoid current.

Abstract: An electromagnetic adjusting device for automatic transmissions of motor vehicles has an electromagnet having a magnetic coil, a substantially cup-shaped housing which surrounds the magnetic coil and is composed of a ferromagnetic material, the housing having a housing bottom, a ferromagnetic central part which extends from the housing bottom and supports the magnetic coil, and a movable armature located before the central part and leaving a working air gap so as to form with the housing and the central part a magnetic circuit which has a magnetic resistance for a magnetic flux, and means for changing the magnetic resistance, the means for changing the magnetic resistance including an axial depression provided in the central part and an axially displaceable ferromagnetic filling member inserted in the depression and limiting with a bottom of the depression an auxiliary air gap.

Abstract: An electromagnetic actuator has a core combined with a coil, and a movable member disposed so as to be attractable to an end face of the core, the movable member having an abutting surface for abutment against the end face of the core. The coil is selectively energized and de-energized to attract the movable member to and release the movable member from the end face of the core. The end face of the core is greater in size than the abutting surface of the movable member.

Abstract: An electromagnetic drive device is proposed comprising an electromagnet (21) having a magnetizable core (22) with a plurality of limbs (23 and 24) and an energizable winding arrangement (35) surrounding at least one limb (23 and 24) of the core (22). Furthermore there is a magnetizable magnet armature (15) able to be moved in relation to the core ((22) by varying the winding arrangement current. The (22) core has at least one U arrangement and is formed essentially by a plurality of sheet metal elements (30) resting against each other and extending athwart the direction of the parallel limbs (23 and 24), the parallel limbs being respectively surrounded by one winding (33 and 34) of the winding arrangement (35).

Abstract: In a magnetic switch for a starter motor, a magnetic core member providing a magnetic flux path is composed of separate components: a first core, a cylindrical yoke and a second core, all contained in a cup-shaped frame in close contact to one another. The first core is forcibly inserted into the cup-shaped frame, and the cylindrical yoke formed by rounding a flat plate into a C-shaped body having a small opening is also forcibly inserted in the cup-shaped frame by squeezing the small opening. The separate components are firmly pressed to each other by an axial force generated by caulking an open end of the cup-shaped frame. A switch cover is connected to the magnetic core member not to loosen the axial force connecting the components. Thus, magnetic resistance increase in the magnetic flux path formed by separate components is effectively suppressed.

Abstract: An iron core comprising an outer yoke, side poles disposed on both end portions of the outer yoke, and a center pole disposed between the side poles, wherein a magnetic path of polar portions of the center pole is formed as an open-circuit. There can be restricted for short-circuiting of magnetic flux of permanent magnets and thrust of an oscillator disposed at an air gap formed between electromagnets can be improved.

Abstract: An automotive emission control valve, such as an EGR valve, has a solenoid for operating a valve element. The solenoid has a stator and an armature. A pole piece of the stator is cooperatively associated with a wall of the armature and comprises a channel that is annular about, and concentric with, a centerline of armature motion. In radial cross section the channel is defined by radially inner and outer walls that form an open throat for the channel, allowing an end portion of the armature wall to move within the channel as the armature is displaced along the centerline. Various constructions for the inner and outer walls are disclosed, including tapers for both walls.

Abstract: A spark ignition system for igniting fuel in an internal combustion engine is described. The spark ignition system includes a magnetic core-coil assembly having a ferromagnetic amorphous metal magnetic core and driver electronics. The core-coil assembly and driver electronics are capable of operating with a rapid charge and discharge cycle to produce a high spark pulse rate.

Abstract: The invention relates to a magnetic switch having a yoke which has the shape of a rotationally symmetrical cup on the base of which is arranged a permanent magnet. The flux of the permanent magnet is conducted via a core, which has a radial core flange, to the plate-shaped armature. For the operational air gap effective between the armature and the core and the yoke and the magnetic resistance WA thereof, the following relation applies in relation to the marginal air gap formed between the core flange and the yoke: WA<WR. As a result of the rotational symmetry with a yoke having the shape of a cup, it is possible to generate a high holding force for the armature with a small structural volume.

Abstract: An electromagnetic actuator for an automotive internal combustion engine is provided which has a stator, the weight of which is reduced. The electromagnetic actuator has a pair of electromagnets each made up of a stator and a coil, an armature disposed between the pair of electromagnets so as to be reciprocable therebetween, and a first stem provided on one side of the armature for transmitting the movement of the armature to external. The stator is formed by powder molding.

Abstract: A core of a solenoid actuator is provided which is improved in durability and at the same time ensures high energy efficiency of the solenoid actuator. The core of the solenoid actuator attracts an armature during operation of the solenoid actuator. A plurality of core plates are formed of a magnetically soft material and laminated in a predetermined direction orthogonal to a direction of attracting the armature to form a laminated stack. The core plates form magnetic circuits between the armature and the core plates themselves during the operation of the solenoid actuator. Two core holders formed of a non-magnetic material sandwiches the laminated stack of the plurality of core plates from opposite sides along the predetermined direction. The plurality of core plates are each coated with insulating film, which insulate adjacent two core plates from each other.

Abstract: A bulk amorphous metal magnetic component has a plurality of layers of ferromagnetic amorphous metal strips laminated together to form a generally three-dimensional part having the shape of a polyhedron. The bulk amorphous metal magnetic component may include an arcuate surface, and preferably includes two arcuate surfaces that are disposed opposite each other. The magnetic component is operable at frequencies ranging from between approximately 50 Hz and 20,000 Hz. When the component is excited at an excitation frequency “f” to a peak induction level Bmax, it exhibits a core-loss less than “L” wherein L is given by the formula L=0.0074 f (Bmax)1.3+0.000282 f1.5(Bmax)2.4, said core loss, said excitation frequency and said peak induction level being measured in watts per kilogram, hertz, and teslas, respectively.

Abstract: A bulk amorphous metal magnetic component has a plurality of layers of amorphous metal strips laminated together to form a generally three-dimensional part having the shape of a polyhedron. The bulk amorphous metal magnetic component may include an arcuate surface, and preferably includes two arcuate surfaces that are disposed opposite each other. The magnetic component is operable at frequencies ranging from between approximately 50 Hz and 20,000 Hz. When the component is excited at an excitation frequency “f” to a peak induction level Bmax, it exhibits a core-loss less than “L” wherein L is given by the formula L=0.0074 f (Bmax)1.3+0.000282 f1.5 (Bmax)2.4, said core loss, said excitation frequency and said peak induction level being measured in watts per kilogram, hertz, and teslas, respectively.

Abstract: A magnet valve, especially for tank venting in motor vehicles, having at least one valve opening and having a valve member, which for opening and closing cooperates with the at least one valve opening and which, forming a magnet armature of an electromagnet, is disposed opposite a magnet core of the electromagnet, an exciter coil being disposed on a coil carrier that is disposed in a magnet housing and surrounds the magnet core, and a thread being provided in the magnet housing, which thread is screwed to a first male-threaded portion of the magnet core, wherein a second male-threaded portion is disposed on the magnet core, which male-threaded portion, as the magnet core is screwed into the magnet housing, forms a thread course in the coil carrier.

Abstract: A bulk amorphous metal magnetic component has a plurality of layers of amorphous metal strips laminated together to form a generally three-dimensional part having the shape of a polyhedron. The bulk amorphous metal magnetic component may include an arcuate surface, and preferably includes two arcuate surfaces that are disposed opposite each other. The magnetic component is operable at frequencies ranging from between approximately 60 Hz and 20,000 Hz and exhibits a core-loss of between less than or equal to approximately 1 watt-per-kilogram of amorphous metal material for a flux density of 1.4 T and when operated at a frequency of approximately 60 Hz, and a core-loss of less than or approximately equal to 70 watts-per-kilogram of amorphous metal material for a flux density of 0.30T and when operated at a frequency of approximately 20,000 Hz.

Abstract: The present invention relates to an actuator for electromagnetic valve control in which the yokes of the electromagnets have a slotted design by means of the yokes consisting of a plurality of solid parts joined to one another.

Abstract: The present invention relates to an electromagnetic valve which includes a valve housing with a valve seat member and a valve closure member controlled by a magnet armature, a valve coil arranged close to the magnet armature and delimited by a yoke ring, and a housing portion which closes the valve housing and on which the magnet armature is supported. The valve housing, the housing portion closing the valve housing, the yoke ring and the magnet armature are made of a magnetic-flux conductive material, and the magnetic circuit between the yoke ring and the valve housing is closed by way of a ferromagnetic annular piece fitted to the valve housing and/or by way of a ferromagnetic accommodating member which carries the valve housing.

Abstract: To provide an electromagnetic actuator, having a large stroke and capable of producing the maximum thrust at a retreated stroke end, which is simple in structure and easy to manufacture. The electromagnetic actuator comprises an electromagnetic coil 1, a magnetic frame 3 arranged on the periphery thereof, a movable iron core 5 slidable in a central hole 4 of the coil 1, a first sleeve 6 coupled with the magnetic frame 3 at one end side of the central hole 4 of the coil, and a second sleeve 7 coupled with the magnetic frame 3 at the other end side of the central hole 4. The second sleeve 7 is spaced from the first sleeve 6 with a space (A+C) in the axial direction, and has an end thereof opposing the first sleeve 6 extended to a position in close proximity to the movable iron core 5 when the movable iron core 5 is at the retreated stroke end, but without being substantially fitted thereon, and extended to a position apart therefrom by a micro-distance A.

Abstract: A permanent magnet latching solenoid with a central passage carrying a reciprocative armature has a magnetically permeable bushing press-fit in each end of the bobbin. The outer ends of the bushings define the outer ends of the bore. A separate preformed magnetically permeable frame surrounds the bobbin and includes end wall portions that abut the outer ends of the bushings. The bobbin assembly is inserted laterally into the frame, with the ends of the bushings against the ends of the frame. Openings in the end walls of the frame accommodate free passage of an operator rod element which is affixed to the armature.

Abstract: Electromagnetic actuator for moving a contact into a switched-on or switched-off state, comprising a contact-actuating rod which is displaceable in the longitudinal direction between a first position, corresponding to the switched-off state, and a second position, corresponding to the switched-on state. A core which is made of magnetizable material and interacts with a switch-on coil is attached to the contact-actuating rod. Also present is a pole piece which is made of magnetizable material and of which that face which is directed towards the core, in the first position of the contact-actuating rod, is arranged at an air-gap distance from that surface of the core which is directed perpendicular to the direction of displacement, and in the second position bears as closely as possible against the said core surface. The actuator furthermore comprises a yoke made of magnetizable material for closing the magnetic flux circuit of the switch-on coil through the pole piece and the core.

Abstract: An electromagnetic relay has an iron core, an armature, a coil wound around the iron core, a yoke, a hinge spring, and a joining structure. The yoke is fastened rigidly to the iron core and has an engaging hole and a fitting portion. The hinge spring is used to support the armature rotatably on the yoke, and the joining structure is used to join the hinge spring to the yoke in the electromagnetic relay. The hinge spring has a tongue and a dish-shaped portion, and the yoke has an engaging hole and a fitting portion for engaging with the tongue and the dish-shaped portion. The hinge spring is joined to the yoke by inserting and fitting the hinge spring into the yoke. This structure serves to simplify the process of assembling the hinge spring to the yoke and drastically reduce the number of assembling steps required.

Abstract: A solenoid valve of a type wherein a yoke is provided thereon with a coil, a plunger arranged in the yoke coaxial therewith so as to be brought into a linear movement upon excitation of the coil and characterized in that a coating, such as Teflon®, is provided on at least one of an outer surface of the plunger and an inner surface of the yoke.

Abstract: An electromagnetic assembly includes a casing, a solenoid disposed inside the casing, a stationary magnetic core, and a movable magnetic core. The stationary magnetic core is disposed at least partially inside the solenoid and is fixed relative to the solenoid and the casing, while the movable magnetic core is disposed for reciprocation partially inside the solenoid along an axis. The stationary magnetic core, the movable magnetic core, the solenoid, and the casing have rectangular or square cross-sections in planes oriented essentially perpendicularly to the axis.

Abstract: The improved solenoid actuator assembly of the present invention includes a solenoid stator assembly positioned in an actuator housing and a flux dissipation reducing feature which minimizes flux leakage into the housing thereby maximizing the attractive force and minimizing the response time. The flux dissipation reducing feature includes a slot formed in the housing adjacent each outer face of the solenoid stator pole pieces thereby avoiding a metallic housing wall into which leakage may occur. The slots also permit the cross sectional area of the pole pieces to be maximized thereby increasing the available attractive force. The solenoid stator assembly requires only a single housing which functions to directly support the laminate stack assembly without an intermediate housing while also functioning as an injector body component subject to the compressive assembly load of the injector and including high pressure fuel passages.

Abstract: A molding machine includes a drive unit for linearly moving a movable body, such as a movable platen of a clamping apparatus. The drive unit includes a linear motor. The linear motor includes a linear movement body having moving-side magnetic-pole portions and supported in an axially movable manner, and a stationary body having stationary-side magnetic-pole portions adapted to linearly move the linear movement body. The linear movement body is connected to the movable body (movable platen). The linear movement body has moving-side inclined surfaces on which part of the moving-side magnetic-pole portions are disposed. The stationary body has stationary-side inclined surfaces which face the moving-side inclined surfaces and on which part of the stationary-side magnetic-pole portions are disposed.

Abstract: An electromagnet having one or more coils wrapped around a plate-shaped core produces a uniaxial magnetic filed in the vicinity of a substrate surface for orienting a magnetic film deposited onto the substrate surface. Variations in the magnetic mass of the plate-shaped core or in the magnetic permeability of the core mass are made to reduce angular skew and to improve uniformity of the uniaxial magnetic field. The variations generally involve a reduction in magnetic mass or permeability near a center of the core with respect to a periphery of the core. Cavities of various sizes and shapes but having symmetry with a magnetic axis can be formed in the core for this purpose.

Abstract: A rotary solenoid is disclosed which comprises a support member, a U-shaped core secured to the support member such that a limb of the core extends through an opening provided in the support member, a coil encircling part of the core, the coil being carried by the support member, and an armature rotatably mounted upon the support member.

Abstract: A solenoid comprising a solenoid coil having a longitudinal hole at the center of a bobbin made of a non-magnetic material and a coil winding wound around the peripheral wall of the bobbin. A yoke comprising a peripheral side plate, an upper end plate and a lower end plate all for the covering the outer peripheral surface and both end surfaces of solenoid coil, a pole core disposed at one end of the longitudinal hole and a plunger fitted slidably into the other end of the longitudinal hole. The solenoid further comprises a protrusion member for forming an irregular magnetic field, formed integrally at the center of the yoke, and a recess for fitting the protrusion member from the end surface of the peripheral wall of the bobbin formed in the peripheral wall.

Abstract: A molding machine includes a drive unit for rotating and linearly moving a movable body. The drive unit includes a linear motor and a rotary motor. The linear motor includes a linear movement body having moving-side magnetic-pole portions and supported in an axially movable manner and a stationary body having stationary-side magnetic-pole portions adapted to linearly move the linear movement body. The linear movement body has moving-side inclined surfaces on which part of the moving-side magnetic-pole portions are disposed. The stationary body has stationary-side inclined surfaces which face the moving-side inclined surfaces and on which part of the stationary-side magnetic-pole portions are disposed. The rotary motor is incorporated into the linear movement body and is adapted to rotate an output shaft connected to the movable body.

Abstract: A monophase electromagnetic actuator including at least a ferromagnetic part integral with a member movable along a direction Y, a fixed stator part made of soft magnetic material and including at least on electrical coil, and a thin transversely magnetized permanent magnet. The fixed stator part and the ferromagnetic part define between each other at least two air gaps arranged symmetrically with respect to the medial plane perpendicular to the axis of displacement of the movable member and passing through the middle of the permanent magnet. The length of the ferromagnetic part is approximately equal to the length of the permanent magnet.

Abstract: A gas flow control valve for quietly regulating the flow of a gas. The valve includes first and second coaxially oriented elongate tubes of magnetic material and an elongate sleeve of nonmagnetic material coaxially connecting the tubes. An electric coil assembly is disposed around the sleeve. A cover of magnetic material is provided around the coil and is in contact with the tubes. A nozzle opening is disposed within the first tube and has a valve seat encircling the nozzle opening. An elongate armature is axially slidably disposed within the sleeve and the first and second tubes and is moveable between first and second positions. The armature has a first end with an elastomeric seal member which abuts the valve seat when the armature is in the first position thereof to block the flow of gas. The armature further includes a gas flow passageway extending axially to a second end thereof. An elastically yieldable member is provided for continually urging the armature toward the first position thereof.

Abstract: In an electromagnetic valve applicable to an evaporated fuel purge system of a vehicular internal combustion engine and a method for manufacturing the same, a magnetic core member is caulked to a housing at an accurate position thereof under a spinning process. The core member includes: a relatively large diameter portion; a relatively small diameter portion; and a whole peripherally caulked portion. With the relatively large diameter portion inserted into a core member inserting hole of a valve casing, the relatively small diameter portion is inserted into a core member attaching hole of the housing. The whole peripherally caulked portion is formed in an approximately truncated cone shape using a roll of a spinning process device.

Abstract: A tri-core solenoid includes first, second and third core segments. The first and second core segments mate to form a low reluctance mating interconnect. The low reluctance mating interconnect includes, in one example, overlapping regions of the first and second core segments that form a joint surface area substantially in the same plane as the flow of flux through the first and second core segments. The third core segment, such as a plunger or armature, is slideably received in an aperture defined by the first and second core segments. The first core segment includes an end portion preferably having a first pole face that mates with a second pole face on the third core segment. The second core segment has a receiving region, such as a journal or bushing, that slideably receives the third core segment and forms a journal air gap therebetween.

Abstract: A solenoid valve with a ferromagnetic flux frame which, in assembly, locates and retains the components of the solenoid valve without an exterior housing. Preferably, the solenoid valve has an electric coil disposed on a tubular coil bobbin, a plunger received within the bobbin and first and second bodies each having at least one passage with the passages selectively communicated with each other by the plunger. The flux frame preferably has two complementary halves which when mated together interconnect the first and second bodies at opposed ends of the flux frame to retain and locate the parts of the solenoid valve without an overmolded or exterior housing. Preferably, the halves of the flux frame are mated with a snap-fit to facilitate assembly of the solenoid valve.

Abstract: A permanent magnet D.C. torque motor has the stator mounted in cantilever from a base and nested in a cup-shaped rotor journalled for rotation on the base. The permanent magnets are disposed about the inner periphery of the rotor. The stator core has a plurality of radially outwardly directed webs with coils therearound and may be formed integrally as one-piece or laminated. The pole segments may be integrally formed with the web or attached as separate members. The pole segments have truncated cylindrical pole shoe surfaces forming radial air gaps with the rotor magnets. The pole segments extend axially and transversely beyond the webs. The axial pole segment extensions provide increased total flux for a given motor volume without an increase in ampere turns of electrical energization. The motor of the present invention is particularly suitable as an engine air throttle actuator.

Abstract: A solenoid includes a ferrofluid in gaps between the moving and stationary elements which ferrofluid reduces noise caused by activating a plunger positioned within the solenoid. A permanent magnet can be included as a solenoid element to increase magnetic field strength within the solenoid to retain the ferrofluid within the solenoid.

Abstract: A solenoid includes a ferrofluid in gaps between the moving and stationary elements which ferrofluid reduces noise caused by activating a plunger positioned within the solenoid. A permanent magnet can be included as a solenoid element to increase magnetic field strength within the solenoid to retain the ferrofluid within the solenoid. A cushion located between the plunger and a butt toward which it moves also reduces the noise, while the ferrofluid maintains a relatively high solenoid force relative to a solenoid with air gaps.

Abstract: An automotive emission control valve including a body having an internal main flow passage between a first port and a second port, a valve seat circumscribing a transverse cross-sectional area of the passage, a valve member with a stem and a head that seats on and unseats from the valve seat, an actuator that operates the valve member. The actuator provides a magnetic circuit path that includes respective pole pieces at respective opposite axial ends of the actuator. At least one of the pole pieces being a two-part pole piece including a central hub part joined to an outer rim part that is disposed circumferentially about the central hub part.

Abstract: The present solenoid stator assembly is adapted to be mounted upon a mounting seat of a fuel injector valve. The assembly includes a housing having an upper end, a lower end, and a base adapted to fit on the mounting seat of the fuel injector valve. A substantially E-shaped stator core is disposed within the housing. The stator core includes a top portion having a first end and a second end. A first outer pole piece depends substantially perpendicularly from the first end, and a second outer pole piece depends substantially perpendicularly from the second end. The central pole piece is located substantially central to the first and second outer pole pieces, and depends substantially perpendicularly from the top portion in a direction substantially parallel to that of the first and second outer pole pieces. The first and second outer pole pieces and the central pole piece each have a distal end forming a face, each face being substantially flush with the base of the housing.

Abstract: The invention relates to an electromagnetic actuator including at least one electromagnet which has a yoke body (1) provided with a coil winding (6), and an armature (10) which is connected with a setting means and which, against the force of a resetting means (11), assumes a contacting relationship with a pole face (12) of the yoke body (1) when the coil winding (6) is energized. The yoke body (1) has an essentially rectangular outline and has at least two parallel side faces (4). The pole face (12) of the yoke body (1) is formed as a circular surface and the armature (10) is formed as a circular disk.

Abstract: The electrical switching apparatus includes a housing (10), a coil (20) arranged in the housing (10), at least two switch terminals (35,50,60) arranged in the housing (10), a magnetic angle piece (30) in the housing (10) including a core (32) for the coil (20) and an armature (42) resiliently mounted on the magnetic angle piece (30) for making electrical contact between two switch terminals (35,50,60).

Abstract: In an electromagnet with sleeve-shaped magnet housing with integrated valve body, in particular for the actuating of valves, the pole core is developed as a separate part and is surrounded by the sleeve-shaped magnet housing. The magnet housing has inward-directed corrugations distributed uniformly over its circumference which serve as axial support for the pole core in the direction of the electric windings.

Abstract: An electromagnetic relay, having a core 3 fixed by press-fitting in a yoke 4, which is facilitated in attaching operation and eliminated of the possibility, during press-fitting, of being placed in poor contact by metal chips produced by cutting away the yoke 4 by the core 3. The core 3 is provided with a smaller diameter portion 3c at an end portion and is inserted into a center of a bobbin 1 having a coil 2 wound therearound. A cutout 5 is formed in the yoke 4 so as to receive by press-fitting the smaller diameter portion 3c of the core 3. First slant surfaces 6 are formed in the edge of an opening of the cutout 5 such that the wall thickness becomes thinner toward the opening. Second slant surfaces 7 are provided in the form of curved surfaces at the terminal ends of the first slant surfaces in a manner smoothly continuing to a general surface of the yoke 4 and also to the first slant surfaces 6.

Abstract: A functionally gradient permanent magnet is formed as a slab of alloy comprised of a rare earth-transition metal-boron, and areas of a diffused transition metal positioned at points along the length of at least one surface of the slab of alloy.

Abstract: An electromagnetic linear actuator having a stationary annular assembly with a magnetic outer shell and a magnetic inner core. Monostable or bistable control components may be mounted interchangeably between the outer shell and inner core. An assembly which is moveable in the axis of the annular assembly includes two magnetic plates which face the extremities of the annular assembly and a rod which is mounted so that it can slide inside the core. The first core is made of a material chosen for its frictional characteristics. The actuator may be used to control the valve of a regulator in the fuel supply circuit of a satellite engine.

Abstract: An electromechanically actuated fuel injector and a solenoid stator assembly for an electromechanically actuated fuel injector are disclosed. The solenoid stator assembly comprises a cup shaped stator core assembly comprised of a plurality of magneto-conductive wire members of a predetermined length arranged in parallel, adjacent and abutting relationship relative to an adjacent wire member. These wire members are bound at one end thereof for some length less than the entire length of the wire members to form a central pole piece, and splayed umbrella like about the central pole piece at the opposite end thereof to form a first pole piece in concentrically spaced relationship relative to said center pole piece. The stator core thereby has a circular top portion and an open end disposed opposite said top portion and facing an armature in the fuel injector.

Abstract: A latching electromagnet is provided. The electromagnet (300) includes a core (305) having a pole face, a coil of windings (325), and an armature (330). Advantageously, the core has a geometry that locally increases the magnetic flux density to saturation levels.

Abstract: An electromagnetically actuated friction clutch includes a rotatably driven input gear. A rotatable armature is connected to the input gear and includes a friction face and nitrocarburized outer surfaces. A pole piece has a pole face for engaging the friction face of the armature and nitrocarburized outer surfaces. An electromagnet generates an electromagnetic field to shift the armature from a disengaged position to an engaged position wherein the friction face of the armature and the pole face of the pole piece are frictionally engaged. An output shaft is driven by the input gear when the armature is in the engaged position. The nitrocarburized outer surfaces of the armature and the pole piece resist wear, while interior portions of the armature and pole piece direct magnetic flux flow along a desired path.