Abstract: The invention relates to an electromagnetic actuating apparatus with an armature unit, which is guided axially in a housing and is capable of being moved by means of energizing a coil apparatus, contact plug means, which are held in an insulator unit, being associated with the coil apparatus, and an elongated ground contact of the contact plug means being electrically conductively connected to the housing, and the ground contact interacting electrically conductively at an engagement end which is opposite its free end with a yoke section, which is associated with the housing preferably at the front end, in such a way that, in a fitted state, a cutout formed in the engagement end in the ground contact engages over a projection of the yoke section and/or at least partially surrounds it.

Abstract: Electromagnetic actuator having an armature unit which is axially guided in a housing and movable by passing current through a coil device and in particular against a return force of a return spring out of a first stop position defined by means for limiting the stroke, the means for limiting the stroke having a stop element which is mounted terminally in the housing and manufactured by a shaping, stamping, sintering and/or injection moulding method, and which is designed to cooperate with a plunger unit which can be actuated outside the housing and is designed for mechanically moving the armature out of the first stop position.

Abstract: A solenoid plunger for use in solenoid driven multi-line embossing systems is constructed of magnetic steel laminations that are attached to a center block which is machined to mount a solenoid shaft and anti-rotate pins. The laminations are attached to the center block with screws and vacuum epoxy glued for a very high cycle life. The laminated steel construction dramatically reduces eddy currents, which allows the magnetic field to rise and fall much more quickly than a conventional steel plunger. It also increases the magnetic force in the solenoid. This reduction in solenoid plunger eddy currents and increase of magnetic force in the solenoid structure itself operates to increase embosser throughput. The laminated steel construction further reduces embosser solenoid heating which also contributes to improved embossing control.

Abstract: A linear actuating device contains a top magnet and a bottom magnet. The bottom magnet is axially aligned with the top magnet. The top magnet and the bottom magnet have opposing magnetization. A washer is sandwiched between the top magnet and the bottom magnet. A top coil is positioned within the top magnet. A bottom coil is positioned within the bottom magnet. A slug is slidably positioned within the top coil and bottom coil. An actuating member is integral with the slug.

Abstract: An electromagnetic drive system contains an armature that can be displaced along an axis. The armature contains a piston-shaped section. The piston-shaped section is guided in a cylindrical section of the stator. A recess extends through the piston-shaped section substantially in the direction of the axis. The incorporation of the recess results in that a fluid cushion that builds up in front of the piston-shaped section during rapid movement can be relieved through the piston-shaped section.

Abstract: Embodiments of the present invention provide solenoid plungers, solenoid actuators, and solenoid-actuated mechanisms, that provide for an adjustable stroke, adjustable rated force, and adjustable plunger extension that overcome the problems and issues associated with non-adjustable solenoid actuators. In accordance with an embodiment of the present invention, an adjustable solenoid plunger is provided that comprises a stem, a stem tail retention element adjustably coupled to the stem tail, and an armature having an armature bore, the armature adjustably coupled to the stem. The stem engages the armature bore and is adapted for advancement of the armature along at least a portion of the stem. The stem tail retention element is adapted to be advanced along the stem tail so as to adjust the extent of the plunger extending from the solenoid so as to adjust stroke, force, and plunger extension.

Abstract: A plunger for use with a solenoid having a winding defining a bore is provided in an embodiment in accordance with the present invention, comprising a plunger first end, a plunger second end opposite the plunger first end, and a plurality of through-holes defining eyelets disposed in the plunger second end. The plunger first end is adapted to extend within the bore and the plunger second end adapted to extend from the bore. The eyelets are adapted to accept a cable therethrough. In another embodiment, the eyelets are substantially the same size, substantially equally spaced and substantially collinear. In another embodiment, the eyelets are in a staggered arrangement. In another embodiment, the plunger first end comprises a retention portion adapted to couple with a suitable coupler adapted to retain the plunger first end within a bore of a solenoid.

Abstract: An electromagnetic actuator includes a coil, which is formed in an annular shape, a plunger, and a stator, which receives the coil inside the stator and forms a magnetic circuit along inner and outer circumferences of the coil through the plunger. The stator includes first and second stators. The first stator includes a magnetic attraction portion that attracts the plunger in an axial direction of the plunger by magnetic force generated by the coil, and a first yoke portion that covers the outer circumference of the coil. The second stator includes a radial direction magnetism delivery-receipt portion that delivers magnetism in a radial direction of the plunger to and receives magnetism in the radial direction from the plunger, and a second yoke portion that covers the outer circumference of the coil. The first yoke portion and the second yoke portion overlap in the axial direction and are magnetically joined.

Abstract: Embodiments of the present invention provide solenoid plungers, solenoid actuators, and solenoid-actuated mechanisms, that provide for an adjustable stroke, adjustable rated force, and adjustable plunger extension that overcome the problems and issues associated with non-adjustable solenoid actuators. In accordance with an embodiment of the present invention, an adjustable solenoid plunger is provided that comprises a stem and an armature including an axial armature bore. The stem engages the armature bore and is adapted for advancement of the armature along at least a portion of the stem.

Abstract: Electromagnetic actuator for operating at least one movable contact of a switch into a switched-on position or a switched-off position. The electromagnetic actuator (1) has a first magnetic circuit for making a movable (3) and a fixed (4) pole body move towards one another and a second magnetic circuit, separate from the first magnetic circuit, with a permanent magnet (9) and a retaining plate (10). A switching-off coil (15) operates to counteract the magnetic field in the second magnetic circuit so that the actuator (1) can return to a switched-off position. In the axial direction of the actuator (1), the switching-off coil (15) is positioned Gloser to the retaining plate (10) than the permanent magnet (9), as a result of which more effective operation of the actuator is possible. Furthermore, the actuator is constructed from cylindrical elements that are easy to produce and to assemble.

Abstract: A fuel injector 10 may comprise a valve body 14 having a fuel path, a valve seat 23 fixed to a downstream end of the valve body, and a valve 25 that opens and closes a fuel injection hole of the valve seat 23. The valve may be housed within the valve body in a manner allowing sliding. An armature 31 may be attached to an upstream end of the valve 25, and a valve closing element 32 may be attached to a downstream end of the valve 25. A core 21 may be disposed at an upstream side of the armature 31. A downstream end surface of the core 21 faces an upstream end surface of the armature 31. When the valve 25 opens the fuel injection hole, the downstream end surface of the core 21 makes contact with the upstream end surface of the armature 31. A non-magnetic ring 20 may be disposed at an outer circumference side of the armature 31 and the core 21.

Abstract: A linear solenoid is provided which works to pull a plunger to a stator magnetically. The plunger and the stator are aligned to have ends opposed to each other. The end of the stator has formed therein a recess into which the end of the plunger is insertable. The recess has an inward magnetic attraction surface formed on a peripheral edge. The plunger has an outward magnetic attraction surface formed on an outer peripheral edge of the end thereof which faces the inward magnetic attraction surface through a magnetic gap. The inward and outward magnetic attraction surfaces have greater areas defining the magnetic gap, thereby ensuring a greater amount of magnetic attraction pulling the plunger to the stator upon energization of a coil. The recess may alternatively be formed in the end of the plunger.

Abstract: With variable airgap reluctance actuators problems arise due to the relationship between actuator mass and displacement range. By providing opposed surfaces in the actuator stator core and armature which have undulations typically in the form of grooves, slots and projections, a greater displacement range can be achieved whilst maintaining performance above a rated displacement force characteristic. In such circumstances by establishing a necessary rated displacement force characteristic, an actuator can be tailored and designed to meet that characteristic over a desired displacement range which has significantly less mass in comparison with a prior actuator arrangement having flat surfaces.

Abstract: A valve actuator for an internal combustion engine is described having a core having a wound coil located therein, said core further having at least one permanent magnet located at least partially inside or outside said coil and positioned at an angle relative to a direction of movement of an armature. Further, various recesses, indentations, chamfers, bevels, and/or depressions may be included to affect flux leakage, and/or force generation.

Abstract: An electromagnetic actuator comprises an driven member and magnetostrictive elements which change the dimensions thereof when activated or deactivated by selectively applying magnetic flux therein. The driven member is moved in a selected direction when the appropriate elements are activated and deactivated in a controlled manner.

Abstract: A variable force solenoid is described, wherein the solenoid has a relatively long stroke and a relatively low profile. The solenoid includes an armature with at least one tapered surface and a pole piece with at least one tapered surface. The armature and the pole piece may each be provided with multiple tapers on more than one surface thereof.

Abstract: A solenoid is provided which, in the preferred embodiment, has a bobbin having an axial opening in it. A divider is mounted within the opening. Respective ones of a first pole piece and a second pole piece are located on opposite sides of the divider. A permanent magnet is moveably mounted from the axial opening and is moveable independently of the second pole piece between at least a first position adjacent to the divider, and a second position adjacent the second pole piece. The construction provides a fast acting, low cost latching solenoid construction.

Abstract: The invention relates to an electromagnet for actuating a valve. To this end, the electromagnet (28) comprises an armature (58), which can be axially displaced in an armature space (57, 77) and whose axial motion displaces a tappet (29) to the valve. The electromagnet is provided with reflux channel (71.1), which is connected to the armature space (57, 77) and via which the armature space (57, 77) is connected to a tank volume (25) in order to lead away a pressure medium leakage flow that is flowing out of the valve and into the armature space (57, 77).

Abstract: According to a solenoid air valve, a flange portion of a moving core and a flange portion area of a bobbin implement a stop area defining a distance of travel of the moving core in a direction away from a fixed core. An end portion of a shaft portion of the moving core can project outward through an opening of a frame cover, so that a gap between a surface of the frame cover facing the shaft portion and a side surface of the shaft portion (distance: L2) can be minimized. Consequently, a solenoid air valve having a structure allowing improvement in magnetic efficiency by making smaller the gap between the frame and the moving core is provided.

Abstract: A solenoid that has a small body and increased propulsion in a controlled range is provided. The solenoid is characterized by being provided with a bearing 40 formed of a nonmagnetic body, n (where n is a positive integer of zero or above) grooves 56 and n+1 tooth parts 58 that are adjacent to the grooves 56 and function as magnetic poles being provided in a facing surface 52 of a first upper yoke 54a, m (where m is a positive integer of zero or above) grooves 70 and m+1 tooth parts 72, 74 that are adjacent to the grooves 70 and function as magnetic poles being provided in a facing surface 55 of a second upper yoke 54b, n+1 grooves 56 and n+1 tooth parts 58, 59 that are adjacent to the grooves 56 and function as magnetic poles being provided in a surface 52 of the slider 36 that faces the first upper yoke 54a, and m grooves 76 and m tooth parts 78 that are adjacent to the grooves 76 and function as magnetic poles being provided in a surface 55 of the slider 36 that faces the second upper yoke 54b.

Abstract: In a starter, an electromagnetic switch is mounted to a seating. A lead wire of an exciting coil is led to an outside of a switch case by a coil-leading portion and is connected to a male terminal, which is fixed to the coil-leading portion by welding. The coil-leading portion is integrally provided with an end plate portion of a bobbin around which the exciting coil is wound. The coil-leading portion passes through and projects from a bottom surface of the switch case to the outside. A metal member, in a form of a plate, is insert-molded in the seating. A 50 terminal is provided on an end of the metal member and a female terminal is provided on an opposite end of the metal member. When the electromagnetic switch is mounted to a predetermined position of the seating, the female terminal engages with the male terminal.

Abstract: A moving core of a solenoid air valve has a flange portion arranged on a side of a fixed core, provided in a radially projecting manner and having a first diameter, and a shaft portion having a second diameter smaller than the first diameter. Therefore, a sufficient area of magnetic pole is ensured around a rubber packing in the flange portion of the moving core. Consequently, the solenoid air valve structured such that an area of magnetic pole is sufficiently ensured even if the moving core is made thinner in order to ensure a volume of a coil body in reducing the solenoid air valve in size can be provided.

Abstract: A soleniod operated valve has an operating rod attached to the armature with one end of the rod contacting the end of a valve member for effecting movement thereof upon coil energization. A lower bearing is disposed in a lower flux collector adjacent one end of the rod. An upper bearing surface is disposed on an adjustment member threadedly engaging an upper flux collector with the armature return spring between the armature and upper bearing for maximizing bearing separation and improving armature alignment and reducing hysteresis.

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: A brake-transmission shift interlock device 10 for an automatic transmission system includes a solenoid 14 secured to a support member 12 that positions the solenoid 14 so as to block movement of a transmission member 176 to prevent a transmission shifter from being moved from a park position. The solenoid 14 includes a plunger 50 having first and second portions 76 and 78. The second plunger portion 78 engages the transmission member 176 laterally on a side wall 94 if the brake pedal is not depressed and the shifter is in the park position. To prevent the plunger 50 from binding, the second plunger portion 78 is allowed to axially offset from the first plunger portion 76 thereby reducing the required lineal force to move the plunger 50 from a first to a second position when the solenoid 14 is energized.

Abstract: An electric actuated control valve, such as an EGR valve, has a solenoid that can deliver useful force over a longer stroke for operating a valve element.

Abstract: An apparatus for use in components such as servo-valves, regulators and injectors for stabilizing system oscillations. The apparatus includes an armature having at least one groove formed on an exterior surface thereof; a sleeve, the armature being movably disposed in the sleeve; and a spring member disposed in the at least one groove in the armature and in sliding contact with the sleeve wherein the spring member exerts a radially outwardly directed spring force against the sleeve. A method of stabilizing an electromagnetically operated actuator comprises providing an armature having at least one groove formed on an exterior surface thereof; providing a sleeve wherein the armature is movably disposed in the sleeve; and disposing a spring member in the at least one groove in the armature and in sliding contact with the sleeve whereby the spring member exerts a radially outwardly directed spring force against the sleeve.

Abstract: An emission control valve is operated by an electric actuator that has an electric coil, stator structure, and a positioning mechanism, including an armature that is selectively positionable along an axis, for selectively positioning a valve element. The stator structure is separated from the armature by an air gap that includes a non-ferromagnetic guide sleeve that is in surface-to-surface contact with the armature for guiding armature motion along the axis. The guide sleeve and the stator structure are in surface-to-surface contact for mutually concentricity with the axis. Along a region of mutual overlapping a minimum air gap is provided between the guide sleeve and the stator structure by radial spacing between the stator structure and the guide sleeve. Various embodiments are disclosed.

Abstract: A proportionally-controllable solenoid including primary and secondary pole pieces that surround an armature axially movable along an axial channel within the pole pieces. The pole pieces are separated axially by an air gap and are conically tapered toward the gap. The leading and trailing faces of the armature are substantially orthogonal to its direction of travel to minimize radial parasitic forces on these faces. Further, the armature is also lengthened such that the trailing face is always outside the axial channel in the secondary pole piece at all points of axial travel to minimize the pull-back effect of axial flux vectors on the trailing face.

Abstract: The invention relates to a switchgear, especially for actuating valves, comprising a housing (18) and a coil body (10) disposed therein in which a switch element is guided and which is provided with a winding (14) of a conductor (16) that is connected to a plug connector (22) via contact elements (20). At least some sections of the housing (18) and of the plug connector (22) are enclosed by a plastic compound (24), and sealing devices (40) seal off the interior (42) of the switchgear from the surroundings (44). At least one of the sealing devices (40) is configured as a sealing web (48), said sealing web (48) consisting of a meltable material. The sealing web (48) is disposed on the bottom face (50) of a plug plate (26) of the plug connector (22) which faces the housing (18).

Abstract: A DC electromagnet system used in an electrical switchgear, for example in a contactor having a driving coil, includes a fixed, C-shaped magnet yoke and a movable, rod-shaped armature. The yoke has a central web and two legs. The armature is guided in its displacement stroke by guide devices, the free end of the armature being directed toward the central web of the magnet yoke. There is a single working air gap between the free end of the armature and the center of the central web, perpendicular to the longitudinal axis of the armature. The ends of the yoke legs extend to the proximity of the armature and are separated from the armature, each forming a parasitic air gap.

Abstract: An electrically operated solenoid for controlling a valve mechanism, including a coil assembly, a magnetic armature defining a passage extending therethrough, a pole piece defining a passage extending therethrough generally aligned with the passage in the armature, and an actuator pin having a first portion disposed within the passage in the armature and a second portion extending through the passage in the pole piece for engagement with the valve mechanism. The actuator pin is engaged with the armature such that reciprocating movement of the armature correspondingly displaces the actuator pin to control operation of the valve mechanism. An adjustment screw is threadingly engaged within a threaded portion of the armature passage such that displacement of the adjustment screw correspondingly adjusts a position of the actuator pin relative to the armature along an actuation axis.

Abstract: A relay (10), in particular for a starter for an internal combustion engine, is proposed. The relay (10) includes a relay coil (13) and a solenoid armature (22) which can be moved when full battery current flows to the relay coil (13). A contact member (37) can be actuated by the solenoid armature (22), whereby an operating lever (31) is situated on the contact member (37). It is provided that a coupling element (46) connects the operating lever (31) and the solenoid armature (22) with each other in a manner that allows them to slide with limits.

Abstract: A magnetic body case in a solenoid for an electromagnetic valve has a cylindrical skirt portion which surrounds a side face of a bobbin and a cap portion which covers one end face of the bobbin in an axial direction thereof, these skirt portion and cap portion are respectively formed individually, and the magnetic body case is assembled by coupling the cap portion to one end of the skirt portion in the axial direction.

Abstract: A proportional activation magnet (1) for a hydraulic solenoid valve has a pole (3) with a valve cone receiving bore (17) for receiving a valve cone (20) and a pole tube (14) for receiving an armature (30). An armature tappet (33) extends between the armature (30) and valve cone (20). A retention area (35) with a tappet passage opening (36) is provided around the armature tappet (33) in a region between the valve cone receiving bore (17) and pole tube (14). An annular gap with a predefined gap width is formed between the inside of the tappet passage opening (36) and the outside of the armature tappet (33) which extends in the tappet passage opening (36).

Abstract: In a solenoid valve device, a housing has a stopper formed on an inner wall of a fluid passage around an axial end of an accommodation bore. A valve seat member fixed to an inner circumferential wall of the fluid passage has a through-hole causing an input port to communicate with a drain port, a communication bore causing the through-hole to communicate with an output port and first and second valve seats formed around both ends of the through-hole, respectively. A movable member has a contact portion accommodated in the fluid passage between the stopper and the second valve seat. A ball is arranged on an opposite side to the contact portion with respect to the valve seat member. When the movable member moves with a movable core, the contact portion resting at the stopper or the second valve seat defines reciprocating moving stroke of the movable member.

Abstract: An electromagnetic solenoid actuator comprising a cylindrical casing, an electromagnetic coil arranged in the casing, a fixed iron core arranged in the electromagnetic coil, a moving iron core arranged to come in contact with, and separate away from, the fixed iron core, and an operation rod mounted in the moving iron core, wherein provision is made of a position-limiting mechanism for limiting the operation rod to a plurality of operation positions according to a thrust produced by the operation rod in compliance with the amount of electric power fed to the electromagnetic coil.

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: A thrust producer of a moving-magnet type includes a rod supported for upward and downward movements by an apparatus main body through an air hydrostatic bearing and a thrust producer for moving the rod up and down, the thrust producer has a magnet mounted to the rod to be displaced with the rod and a coil provided to the apparatus main body to generate magnetic force when the coil is energized, and the thrust producer produces thrust by an interaction of the magnet and the magnetic force generated by the coil.

Abstract: An automatic player piano is equipped with a key actuating device for moving keys without fingering, and the key actuating device has a retainer embedded in the key bed for adapting plungers of solenoid-operated key actuators to the keys, respectively, wherein the retainer is formed with guide grooves defined between wall portions for permitting sliding portions of the yokes incorporated in the solenoid-operated key actuators therealong, and a worker simply presses the yoke against the wall portions by means of bolts so as to locate the plungers immediately under the associated keys.

Abstract: A solenoid for an electromagnetic valve is provided with a bobbin on which a coil has been wound, a movable iron core fitted into an iron core hole of the bobbin and a fixed magnetic pole member attracting the movable iron core, the movable iron core has a main body portion with an even section fitted into the iron core hole, and a flange portion with an even section formed on a portion extending from the iron core hole of the main body distal end, and the ring has a first portion which is positioned on a distal end side and which has a large diameter hole in which the flange portion is fitted and a second portion which is positioned on a proximal end side and which has a small diameter hole in which the main body portion is fitted.

Abstract: In a solenoid portion of a solenoid valve, a fixed core for axially attracting a plunger due to magnetic force generated by a magnetic coil is divided into two. One is a cylindrical yoke having an opening at an axial end and a bottom at the other axial end. The other one is a cylindrical stator core having a flange protruding radially outwardly at an axial end thereof. The bottom of the yoke is provided with a thick body portion having a center recess. The inner surface of the opening of the yoke is fitted to an outer surface of the flange and the inner surface of the recess of the thick body portion is fitted to an outer surface of the stator core. Accordingly, constructions of molding dies for manufacturing the yoke and the stator core are simple. Further, only limited surfaces of the yoke and the stator core, which are fitted to each other, need accurate dimensions so that magnetic gap is minimized.

Abstract: An emission control valve is operated by an electric actuator that has an electric coil, stator structure, and a positioning mechanism, including an armature that is selectively positionable along an axis, for selectively positioning a valve element. The stator structure is separated from the armature by an air gap that includes a non-ferromagnetic guide sleeve that is in surface-to-surface contact with the armature for guiding armature motion along the axis. The guide sleeve and the stator structure are in surface-to-surface contact for mutually concentricity with the axis. Along a region of mutual overlapping a minimum air gap is provided between the guide sleeve and the stator structure by radial spacing between the stator structure and the guide sleeve. Various embodiments are disclosed.

Abstract: A solenoid includes a pole member of a magnetic material, the pole member including a pole end portion having a pole surface, an armature adapted for movement relative to the pole member between first and second positions and a coil assembly for positioning the armature relative to the pole member. A magnetic shunt structure, which is located adjacent to a pole surface of the pole member, includes at least one magnetic shunt member of a magnetically permeable material, bridging at least a portion of the air gap between the pole face and the armature face, when the armature is spaced apart from the pole member, to provide a low reluctance magnetic flux path between the pole member and the armature, increasing the attractive force between the armature and the pole member. The shunt member can be configured as a ring, as a washer, or as a combination of both a ring and a washer.

Abstract: An electromagnetic valve including a valve housing machine from free cutting steel wherein the housing and the valve's magnetic core are made from identical, high-alloyed chromium and molybdenum constituents, and wherein the valve housing is fabricated from a chromium-nickel alloy and a high-alloyed chromium-molybdenum compound.

Abstract: An electromagnetic actuator, especially for the closure member of a valve, contains a solenoid unit, which has a cylindrical cavity closed at one end and open at the other end. An axially introduced guide tube for a magnetically movable armature is arrestable in the cavity by means of a securing device engageable in a first recess under spring force. To simplify connection of the actuator with and separation of the actuator from the component to be adjusted, provision is made for the securing device to lie completely within the solenoid unit and to snap automatically into the first recess when the guide tube is moved into a desired position in the cavity of the solenoid unit.

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 valve control system for controlling an electromagnetic valve unit is arranged to detect a characteristic of a free vibration of a vibration system in the electromagnetic valve unit when a pair of electromagnets of the electromagnetic valve unit are de-energized and to estimate at least one of a friction quantity and a spring constant of the vibration system on the basis of the detected characteristic of the free vibration. The control system executes the control of the electromagnetic valve unit on the basis of a control parameter determined by one of the estimated friction quantity and the estimated spring constant. This arrangement improves a certainty of softly landing a movable member of the electromagnetic valve unit on the electromagnets.

Abstract: An electromagnet includes a cylindrically shaped electric coil made of magnetic material and wound around a bobbin made of resin material and made of magnetic material, a cylindrically shaped case made of magnetic material and housing the electric coil, a yoke made of magnetic material for forming a magnetic circuit in cooperation with the case, with both longitudinal ends of the yoke facing the bobbin, and a plunger made of magnetic material and disposed in the inner peripheral of the yoke for moving by electromagnetic force in the longitudinal direction when current is supplied to the electric coil. The bobbin and the yoke are integrated with each other by resin forming, with the outer peripheral portion of the yoke facing the inner peripheral portion of the bobbin being subjected to grooved treatment in the longitudinal direction to form at least one groove and/or knurling treatment to form a knurled outer peripheral portion of the yoke.

Abstract: DC electromagnet comprising a magnetic circuit equipped with a yoke and a magnetic core fixed at its ends with vanes and capable of axial displacement. The magnetic core 21 is smooth and the vanes 22,23 are shrink fitted and fixed to the ends of the smooth core. One of the vanes 22 is fixed to the core in a reference position and is then put into contact with the associated flange 25 of yoke 14, and the other vane 23 is shrink fitted and pushed into an adjustable position determined by bringing the yoke 14 into contact with the other flange 26.