Abstract: A magnetically variable differential transformer, comprising: a primary winding; a first secondary winding; a second secondary winding; a non-movable permeable core disposed within the primary winding, the first secondary winding and the second secondary winding; and a movable magnet configured for movement about the primary winding, the first secondary winding and the second secondary winding, wherein movement of the movable magnet causes magnetic saturation of portions of the non-movable permeable core.

Abstract: The present invention provides an electrical steel sheet core for a low-noise transformer capable of effectively lowering noise by suppressing vibration perpendicular to the surfaces of the steel sheets and reducing vibration, and relates to an electrical steel sheet for a low-noise transformer characterized by randomly inserting viscoelastic layers with both viscosity and elasticity into the gaps of the steel sheet lamination layers, and a low-noise transformer formed by using said electrical steel sheet.

Abstract: An inductance component includes a magnetic core (11, 12) forming a magnetic circuit having a magnetic gap, an exciting coil (14) wound around the magnetic core, and a permanent magnet (13) disposed in the magnetic gap. The permanent magnet is greater in sectional area than the magnetic core.

Abstract: An inductance component comprises a magnetic core having at least one magnetic gap, means for generating a direct-current biased magnetic field produced by mounting a permanent magnet in the vicinity of a generally closed magnetic circuit which passes through the magnetic gap in the magnetic core or on the outside thereof, and a coil wound around the magnetic core, wherein the permanent magnet is mounted near the magnetic gap at one or more legs of the magnetic core which sandwich the magnetic gap.

Abstract: Non-linear inductor(s) are used to reduce the percent total harmonic distortion of the harmonics in the line currents in the input side rectifier system of an ac drive system. Several constructions for the non-linear inductor(s) are described. The non-linear inductor(s) may be constructed from E and I laminations. The gap depends on the construction of the middle leg of the E laminations and may have a step with a constant spacing or a variable spacing which depends on the stacking of the laminations. Alternatively the non-linear inductor(s) may be constructed from a toriodal core that either has a step gap or a variable type gap.

Abstract: An inductor component is provided. The inductor component includes a core composed of a hollow core piece and a rod core piece, a bobbin, and bonded magnets. Regarding the hollow core piece and rod core piece, the rod core piece is arranged across the hollow core piece, and joining is performed between the bottom surfaces of both end portions of the rod core piece and the hollow core piece with bonded magnets therebetween.

Abstract: An inductor component according to the present invention includes a magnetic core including at least one magnetic gap having a gap length of about 50 to 10,000 &mgr;m in a magnetic path, a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap, and a coil having at least one turn applied to the magnetic core. The aforementioned magnet for magnetic bias is a bonded magnet containing a resin and a magnet powder dispersed in the resin and having a resistivity of 1 &OHgr;·cm or more. The magnet powder includes a rare-earth magnet powder having an intrinsic coercive force of 5 KOe or more, a Curie point of 300° C. or more, the maximum particle diameter of 150 &mgr;m or less, and an average particle diameter of 2.

Abstract: An inductor component is provided which includes a magnetic core having at least one gap, an excitation coil disposed on the magnetic core so as to form a magnetic path on the magnetic core, at least one permanent magnet disposed near the at least one gap, and at least one first soft magnetic material piece disposed between the at least one permanent magnet and the magnetic core, wherein the first soft magnetic material piece is formed of a soft magnetic material which has a smaller permeability and less eddy current loss than the magnetic core.

Abstract: A method of making a permanent magnet body is provided. The method includes providing a first precursor body comprising a plurality of blocks and magnetizing the first precursor body to form a first permanent magnet body. A recoil magnetization pulse may be applied to the permanent magnet body after the magnetization. The precursor body may be heated during magnetization. A power supply containing a battery may be used to energize a pulsed magnet used to magnetize the precursor body.

Abstract: A magnetic head apparatus with which a magneto-optical recording and reproducing apparatus can be made thin is provided. The magnetic head apparatus includes: a supporting material having an elastic portion; a magnetic head hoisting and lowering member capable of being brought into contact with and separating from the supporting material; a magnetic head pressing member capable of being brought into contact with and separating from the supporting material of a pressing portion. The head main body is capable of moving between a first position in which the head main body approaches or is brought into contact with the information recording medium and a second position in which the head main body is far away from the information recording medium.

Abstract: An inverter transformer is provided which can turn on a plurality of cold cathode fluorescent lamps (CFLs) with a minimized increase in the number of components, thereby reducing costs. The inverter transformer comprises a plurality of bobbins for windings. The plurality of bobbins each having a secondary winding wound thereon and having a bar-shaped inner core inserted therein are connected to one another for integration, and a primary winding is wound in common on the bobbins connected together. A plurality of inner cores and a rectangular frame-shaped outer core are magnetically coupled with each other with non-magnetic sheets interposed therebetween to provide a predetermined leakage inductance. A plurality of CFLs can be turned on with only one outer core, thereby reducing the number of components, downsizing the device, and reducing the cost.

Abstract: An inductor component contains a drum magnetic core made of a magnetic material having a structure including integrated flanges at both ends of a columnar material, a coil wound around the columnar material in the drum magnetic core and placed between the flanges, and a permanent magnet placed in the neighborhood of the drum magnetic core with the coil wound around. This inductor component contains a sleeve core fitted to the outside of the drum magnetic core. The permanent magnet is placed in at least one gap in a closed magnetic circuit formed with the drum magnetic core and the sleeve core in order to apply a direct-current magnetic field in the direction opposite to the direction of a magnetic field generated by a magnetomotive force due to the coil.

Abstract: In an inductive sensor a ferrous core is provided and has generally opposed first and second ends. A winding assembly surrounds the core. First and second magnets are coupled to the first and second ends of the core and are oriented relative to one another so that like magnetic poles are opposing one another along a length defined by the core.

Abstract: In an inductance component in which a cylindrical excitation coil (26) is fitted around a predetermined portion of a magnetic core (21) forming a magnetic path, a permanent magnet (25) is inserted into the magnetic path to apply a magnetic bias to the magnetic core. The permanent magnet is arranged outside the cylindrical excitation coil. It is preferable that the permanent magnet is spaced from the predetermined portion of the magnetic core along the magnetic path at least by a distance which corresponds to ½ of an average of inner diameters of the cylindrical excitation coil.

Abstract: A magnetic core has an open magnetic path and includes a magnetic body forming the open magnetic path and having a soft magnetic property, and a permanent magnet at least at one end of the magnetic path of the magnetic body. A coil assembly includes the magnetic core having the open magnetic path. The magnetic core includes the magnetic body forming the open magnetic path and having the soft magnetic property. The coil assembly also includes the permanent magnet at least at one end of the magnetic path of the magnetic body, and at least one coil having at least one turn wound around the magnetic core. A power supply circuit includes the coil assembly. The coil assembly includes the magnetic core having the open magnetic path. The magnetic core includes the magnetic body forming the open magnetic path and having the soft magnetic property.

Abstract: The present utility model belongs to domestic appliances, especially to devices for fixing the magnetic coil of drive unit in tape recorders, video players or cameras. Two coil bobbin brackets (2) having at least one bobbin hook (2-1) on each of them are mounted on the chassis (50) in their corresponding locking slots. A magnetic coil (3) is mounted between the two coil bobbin brackets (2). A planger (1) is mounted adjacent to one end of the magnetic coil (3), and close to the other end, a magnet (6) is mounted. Moreover at least one coil positioning pin (4) is mounted on that bobbin bracket (2), close to which the magnet 6 is mounted on the magnet bracket (5). The present utility model is simple in structure, costs low, and has a high productivity. The pushing force for the planger (1) is increased, and the utility of the products is improved.

Abstract: A magnetic core having excellent DC superposition characteristics and core-loss characteristics is provided. The magnetic core comprises a magnetically biasing magnet disposed in a magnetic gap thereof to provide a magnetic bias from opposite ends of the magnetic gap to the core. The said magnetically biasing magnet comprises a bond magnet which comprises rare-earth magnetic powder and a binder resin. The rare-earth magnetic powder has an intrinsic coercive force of 5 kOe or more, a Curie temperature Tc of 300° C. or more, specific resistance of 0.1 &OHgr;·cm or more, residual magnetization Br of 1000 to 4000 G and coercive force bHc of a B-H curve of 0.9 kOe or more.

Abstract: A magnetic core (10) is provided with a flange portion (12) protruding outward a winding core portion (11) in a radial direction perpendicular to a center axis (19) of the winding core portion. The winding core portion has an outer peripheral surface (11a) which surrounds the center axis to have a first distance (d1) therebetween. The flange portion is provided with a permanent magnet (15) apart from the center axis by a second distance (d2) greater than the first distance.

Abstract: A coil assembly for a solenoid valve includes a bobbin formed from an electrically insulative material. A bore extends axially through the bobbin. A first flux ring having a sleeve extending axially from an annular base is mounted upon a first end of the bobbin with the sleeve extending into the bobbin bore. Similarly, a second flux ring also having a sleeve extending from an annular base is mounted upon a second end of the bobbin that is opposite from the first flux ring with its sleeve extending into the bobbin bore. The flux rings are formed from a magnetically permeable material that has a high heat conductivity. Magnet wire is wound upon the assembled bobbin and flux rings to form the coil assembly.

Abstract: An inductance component includes a magnetic core (11, 12) forming a magnetic circuit having a magnetic gap, an exciting coil (14) wound around the magnetic core, and a permanent magnet (13) disposed in the magnetic gap. The permanent magnet is greater in sectional area than the magnetic core.

Abstract: A rotary position sensor featuring a robust and simply constructed magnetic field assembly which provides a uniform magnetic field in the working air gap for a conventional mangetosensitive device located thereinside. The magnetic field assembly includes a plastic casing having a blind hollow, magnet pocket located at the blind end of the hollow, and a pair of diametrically opposed pole piece pockets oriented in upstanding relation to the magnet pocket. A permanent magnet is snapped into the magnet pocket, and a pole piece is respectively snapped into each of the pole piece pockets. The pole pieces may be rectangular or arc shaped, wherein the space therebetween forms the working air gap into which the magentosensitive device is placed. The magnetic field established in the working air gap is transverse to the axis of the blind hollow, and is generally uniform.

Abstract: A method of making a permanent magnet body is provided. The method includes providing a first precursor body comprising a plurality of blocks and magnetizing the first precursor body to form a first permanent magnet body. A recoil magnetization pulse may be applied to the permanent magnet body after the magnetization. The precursor body may be heated during magnetization. A power supply containing a battery may be used to energize a pulsed magnet used to magnetize the precursor body.

Abstract: In order to provide an inductance part having excellent DC superposition characteristic and core-loss, a magnetically biasing magnet, which is disposed in a magnetic gap of a magnetic core, is a bond magnet comprising magnetic powder and plastic resin with the content of the resin being 20% or more on the base of volumetric ratio and which has a specific resistance of 0.1 &OHgr;·cm or more. The magnetic powder used is rare-earth magnetic powder having an intrinsic coercive force of 5 kOe or more, Curie point of 300° C. or more, and an average particle size of 2.0-50 &mgr;m. A magnetically biasing magnet used in an inductance part that is treated by the reflow soldering method has a resin content of 30% or more and the magnetic powder used therein is Sm—Co magnetic powder having an intrinsic coercive force of 10 kOe or more, Curie point of 500° C. or more, and an average particle size of 2.5-50 &mgr;m.

Abstract: A rotary position sensor featuring a robust and simply constructed magnetic field assembly which provides a uniform magnetic field in the working air gap for a conventional magnetosensitive device located thereinside. The magnetic field assembly includes a plastic casing having a blind hollow, magnet pocket located at the blind end of the hollow, and a pair of diametrically opposed pole piece pockets oriented in upstanding relation to the magnet pocket. A permanent magnet is snapped into the magnet pocket, and a pole piece is respectively snapped into each of the pole piece pockets. The pole pieces may be rectangular or arc shaped, wherein the space therebetween forms the working air gap into which the magnetosensitive device is placed. The magnetic field established in the working air gap is transverse to the axis of the blind hollow, and is generally uniform.

Abstract: A magnet assembly including spacers having chamfered posts insertable in post holes of opposed spaced backirons. For assembly, chamfered posts are inserted into post holes on a first backiron. A second backiron is supported above the first backiron by an assembly slide to retain the second backiron against the magnetic attraction between the first and second backirons for preassembly alignment of the post holes relative to spacer posts. The assembly slide is withdrawn from the second backiron so that the second backiron is attracted toward the first backiron and spacer posts are inserted into post holes on the second backiron. A method for assembling a magnet assembly using an assembly slide to support a second backiron above a first backiron and withdrawing the slide from the second backiron to assemble components.

Abstract: An inductor component according to the present invention includes a magnetic core including at least one magnetic gap having a gap length of about 50 to 10,000 &mgr;m in a magnetic path, a magnet for magnetic bias arranged in the neighborhood of the magnetic gap in order to supply magnetic bias from both sides of the magnetic gap, and a coil having at least one turn applied to the magnetic core. The aforementioned magnet for magnetic bias is a bonded magnet containing a resin and a magnet powder dispersed in the resin and having a resistivity of 1 &OHgr;·cm or more. The magnet powder includes a rare-earth magnet powder having an intrinsic coercive force of 5 KOe or more, a Curie point of 300° C. or more, the maximum particle diameter of 150 &mgr;m or less, and an average particle diameter of 2.0 to 50 &mgr;m and coated with inorganic glass, and the rare-earth magnet powder is selected from the group consisting of a Sm-Co magnet powder, Nd-Fe-B magnet powder, and Sm-Fe-N magnet powder.

Abstract: In an inverter transformer, since a plurality of secondary windings 2, 2 are wound around a plurality of bar-shaped magnetic cores 3, 3 which are formed independently of each other and electromagnetically coupled to a primary winding 1 with equivalent characteristics, there are obtained a plurality of secondary windings 2, 2 which function independently of each other and are electromagnetically equivalent to each other as well, and an open magnetic circuit structure. It does not happen that the numbers of both the primary and secondary winding increase in proportion to the increase in the number of cold cathode lamps, but only the number of the secondary winding increases while the primary winding is common and does not increase in number.

Abstract: In an inductance component in which a cylindrical excitation coil (26) is fitted around a predetermined portion of a magnetic core (21) forming a magnetic path, a permanent magnet (25) is inserted into the magnetic path to apply a magnetic bias to the magnetic core. The permanent magnet is arranged outside the cylindrical excitation coil. It is preferable that the permanent magnet is spaced from the predetermined portion of the magnetic core along the magnetic path at least by a distance which corresponds to ½ of an average of inner diameters of the cylindrical excitation coil.

Abstract: A starter module for a discharge lamp, especially for a motor vehicle, includes a high tension transformer which has a magnetic circuit component such as an annular core, on which a primary winding (1b) and a secondary winding are wound. The transformer further includes an arrangement for modifying its magnetic characteristics so as to reduce the saturation level of the secondary winding.

Abstract: A composite magnetic material comprises a ferrite powder and a resin, in which the ferrite powder comprises a cobalt substituted Y type hexagonal ferrite (2BaO.2CoO.6Fe2O3) or cobalt substituted Z type hexagonal ferrite (3BaO.2CoO.12Fe2O3), and the permeability at 2 GHz is 90% or more of that at 1 MHz.

Abstract: A magnetic core (10) is provided with a flange portion (12) protruding outward a winding core portion (11) in a radial direction perpendicular to a center axis (19) of the winding core portion. The winding core portion has an outer peripheral surface (11a) which surrounds the center axis to have a first distance (d1) therebetween. The flange portion is provided with a permanent magnet (15) apart from the center axis by a second distance (d2) greater than the first distance.

Abstract: An ignition coil for an internal combustion engine is mainly made up of a transformer part and a control circuit part and a connecting part, and the transformer part is made up of a iron core which forms an open magnetic path, magnets, a secondary spool, a secondary coil, a primary spool and a primary coil. By respectively setting the cross-sectional area SC of the iron core between 39 to 54 mm2, the ratio of the cross-sectional area SM of the magnets with the cross-sectional area SC of the iron core in the 0.7 to 1.4 range, the ratio of the axial direction length Lc of the iron core with the winding width L of the primary and secondary coils in the 0.9 to 1.2 range, and the winding width L in the 50 to 90 mm range, the primary energy produced in the primary coil can be increased without increasing the external diameter A of the case.

Abstract: Guitar pickups are provided herein comprising an upper bobbin, a ferromagnetic steel plate and a lower bobbin, stacked on top of each other, oriented longitudinally and laterally substantially the same, and held together by ferromagnetic screws. An upper coil is wounded around a middle section of the upper bobbin, and a lower coil is wounded in an opposite manner around a middle section of the lower bobbin, whereby the upper and lower coils are connected in series. The upper and lower bobbins, and steel plate each include a plurality of coaxial apertures to receive corresponding permanent magnetic pole pieces that extend from the upper bobbin to the lower bobbin. The upper and lower bobbins include additional apertures to receive ferromagnetic cylinders to selectively change the tonal characteristics of the guitar. The pickups may include a pair of ferromagnetic plates attached to the longitudinal sides of the lower bobbin that extend upwards to about the middle of the upper coil.

Abstract: A pickup has an upper bobbin which is elongated along a longitudinal plane, a lower bobbin which is elongated along the longitudinal plane, permanent magnetic pole pieces situated within holes in the upper and lower bobbins, screws holding said bobbins together, a lower winding wound longitudinally around the lower bobbin, and a single, uniformally flat non-magnetized ferromagnetic plate having opposing ends. The ends are parallel to the longitudinal plane and terminate in a plane approximately below the upper winding. The plate is completely dispose beneath the bobbins and parallel thereto.

Abstract: A variable linearity coil has a coil which is wound around a magnetic core, a permanent magnet for charging a bias magnetic field to the magnetic core, and a magnetic field adjusting coil for adjusting the bias magnetic field. The coil and the magnetic field adjusting coil are respectively disposed horizontally such that an axial line of each of the coils lies perpendicular to lead terminals to which terminal ends of each of the coils are connected. The coil, the magnetic field adjusting coil, and the permanent magnet may be contained in a casing and the terminal ends of each of the coil and the magnetic field adjusting coil are connected to lead terminals which are embedded into the casing.

Abstract: To drastically increase output energy generated by means of an electromagnetic function in a small-sized ignition coil apparatus having a plurality of magnetic circuits arranged around and coaxially with a hole for passing therethrough a shaft.

Abstract: An ignition coil for a spark ignition engine includes a cylindrical magnetic core having opposite first and second ends. Preferably, the magnetic core has a circular cross section. Permanent magnets similarly shaped as the core are disposed at the ends of the magnetic core. The magnets are made from a microencapsulated magnetic material, resulting in increased resisitivity and decreased eddy current loss. By using the microencapsulated magnets, the voltage output of the ignition coil is increased while requiring no additional input energy. A primary winding is wound about the magnetic core between the first and second ends. A secondary winding assembly is disposed about the primary winding and the core. The secondary winding assembly includes a spool and secondary winding wound thereon. The secondary winding is inductively coupled to the primary winding. An outer case is disposed about said magnetic core, magnets and the primary and secondary windings.

Abstract: A soft magnetic core is substantially cylindrical and a linear-shaped coil conductor is inserted through a hole in the central portion of the soft magnetic core. A hard magnetic material sheet has areas which are magnetized in a thickness direction thereof and the areas are arranged in strips so that a magnetization direction of adjacent strips is mutually opposite. The hard magnetic material is wound on the outside surface of the soft magnetic core and is fixed to the soft magnetic core. The direction of the areas formed as strips of the hard magnetic material is substantially perpendicular to the axial direction of the coil conductor.

Abstract: A variable linearity coil has a coil which is wound around a first core, a permanent magnet for charging a bias magnetic field to the first core, a bias magnetic field adjusting coil which is wound around a second core, and an electrically insulating base for mounting thereon the coil, the permanent magnet, and the magnetic field adjusting coil. The first core and the second core are placed one on top of the other with a non-magnetic and shock-absorbing spacer in between. Alternatively, the first core and the second core may be placed one on top of the other with a non-magnetic spacer in between, and a combination of the first core, the second core and the non-magnetic spacer is mounted on the base with a shock-absorbing spacer between the combination and the base.

Abstract: An ignition coil, particularly for use in connection with an internal combustion engine, wherein a toroidal permanent magnet is located at one end thereof between the magnetic core and the outer cylinder. This magnet provides a reverse bias magnetic field which interacts with the field generated by the primary coil to produce a composite magnetic field which increases the efficiency of the ignition coil. The reverse bias magnetic field acts in the opposite direction from the magnetic field generated by the primary coil. In another embodiment of the coil, a support is provided in which the toroidal magnet is placed. The support may have an open top or open sides. In the former case, the complete magnet is pressed into the support and retained by gripping portions. In the latter case, the magnet is composed of at least two members, each of which is pressed into the magnet holding chamber formed by the support. Gripping portions retain the members in position.

Abstract: An ignition coil having a transformer surrounding a cylindrical magnetic core. The transformer has a primary coil, to which a DC potential is applied in bursts and which generates a primary magnetic field, and a secondary coil, which retrieves induced electromotive force. An outer cylinder, surrounding the transformer, is also provided. At at least one end of the ignition coil at least one toroidal magnet is located. The inside and outside perimeters of the toroidal magnets have polarities which are opposite to each other. When a plurality of magnets is provided, they are nested inside one another between the magnetic core and the outer cylinder. The direction of the reverse biasing magnetic field generated by the magnet(s) is opposite to that of primary magnetic field generated by the primary coil. The foregoing construction provides a compact ignition coil which is efficient in operation and is capable of making effective use of the induced electromotive force generated.

Abstract: The invention is directed to an ignition coil for an internal combustion engine which includes a columnar member having a plurality of magnetic plates, e.g., silicon steel plates stacked one on the other with stacked portions formed on the magnetic plates. The magnetic columnar member includes a first portion having a plurality of magnetic plates stacked one on the other in accordance with increase of a width of each plate, a second portion connected to the first portion and having a plurality of magnetic plates with the same width stacked stacked one on the other, and a third portion connected to the second portion and having a plurality of magnetic plates stacked one on the other in accordance with decrease of a width of each plate, thereby to form the columnar member with a middle portion thereof having a substantially circular cross section.

Abstract: A static magnet dynamo including at least one permanent magnet having different poles; a first core comprising a soft magnetic material and which couples the different poles of the permanent magnet to form a closed magnetic path therein; a second core comprising a soft magnetic material which couples to the closed magnetic path via a paramagnetic material to form an open magnetic path; a magnetized coil wound around a portion of the first core where the closed magnetic path is formed; and an induction coil wound around a portion of the second core. A direction of a flux of the closed magnetic path is changed by applying an alternating voltage to the magnetized coil, generating an electromotive force in the induction coil by electromagnetic induction due changes in a flux of the open magnetic path induced by the change in direction of the flux of the closed magnetic path.

Abstract: A D.C. reactor has a core structure having two opposed cores separated by a magnetic gap, to form a closed magnetic circuit. A coil is wound on one or both of the cores. A pair of permanent magnets for biasing are disposed on the core structure. The bias flux generated by the permanent magnets and the flux generated by the coil to flow in opposite directions. Bypass means for causing the bias flux generated by the permanent magnets to bypass the magnetic gap are provided. In an embodiment the core structure comprises an E-shape core and an I-shaped core, the magnetic gap is defined between a center leg of the E-shaped core and the I-shaped core, the coil is wound on the center leg of the E-shaped core, and each permanent magnet is shaped as a rectangle and disposed on both side surfaces of the center leg of the E-shaped core.

Abstract: A plug cap incorporated type ignition coil is provided with a primary coil 20 and a secondary coil 30 inserted in a case 10. After a cushion member 80, a magnet 82, and then a core 40 are inserted in order in a primary coil bobbin 22 of a generally cylindrical bottomed shape, the case 10 is filled with potting resin 70. There is interposed a bottom wall portion of the primary coil bobbin 22 between one end 42 of the core 40 and the potting resin 70. Accordingly, even though stress resulting from the difference in thermal shrinkage between the core 40, the primary coil bobbin 22 and the potting resin 70 is caused, the stress is absorbed by elasticity of the primary coil bobbin 22 and as a result, the potting resin 70 is hard to cause a crack. Also, even though the core is affected by the thermal shrinkage, the magnet 82 is hard to destroy.

Abstract: The invention is directed to an ignition coil for an internal combustion engine which includes a housing having therein a first core, a second core which is received in the housing and magnetically connected to the first core for forming a magnetic path therewith, a bobbin having a cylindrical portion for receiving therein the second core with an end face thereof exposed to the outside of the cylindrical portion, a primary winding wound around the bobbin, a secondary winding wound around the primary winding in co-axial relationship therewith, and a permanent magnet which is disposed between the first core and the second core. The permanent magnet has a planar surface connected to the end face of the second core, and an extending end portion which extends out of the end face of the second core. The housing and the bobbin are arranged to enclose the extending end portion of the permanent magnet.

Abstract: An ignition apparatus for an internal-combustion engine comprises a first iron-core section around which a primary coil of an ignition coil is wound; a secondary coil which is wound around the outside of the primary coil; a second iron-core section disposed in the outside of the secondary coil, which forms a closed magnetic path together with the first iron-core section; a housing case which accommodates the primary and secondary coils; and an insulating resin layer composed of first and second resin sections arranged between the housing case and the secondary coil; wherein the first resin section between the second iron-core section and the secondary coil is made thicker than the second resin section which is the part of the insulating resin layer other than the one thereof.

Abstract: The invention is directed to an ignition coil for an internal combustion engine which includes a columnar member having a plurality of magnetic plates, e.g., silicon steel plates stacked one on the other, each of which is a flat plate with its opposite ends having a width greater than that of its middle portion. Each silicon steel plate has a middle portion whose width is gradually increased from the plates placed at the opposite sides of the columnar member to the plate placed in the center of the columnar member, to form a circular cross section. Whereas, the opposite end portions of the columnar member have a rectangular cross section which is greater in area than the circular cross section of the middle portion, respectively. A plurality of recesses are formed on one side of each steel plate, and a plurality of protrusions are formed on the other side of each steel plate.

Abstract: An inner core for an ignition coil is inserted into a bobbin, around which a primary winding and a secondary winding are disposed. An outer core is inserted into a housing to form a magnetic circuit with the inner core. A magnet member, which is made of a permanent magnet material such as Sm.sub.1 Co.sub.5, is connected to the inner core. The bobbin, which is assembled with the inner core, the magnet member, the primary and secondary windings, is inserted into the housing, with the magnet member positioned between the inner core and the outer core, and then the inside of the housing is molded by a synthetic resin. Thereafter, the magnet member is magnetized to provide a predetermined magnetic force. The magnet member may be molded by Sm.sub.1 Co.sub.5 to form a plate having a thickness of 1.5 mm and more.

Abstract: A rotary transformer includes a rotor core formed by stacking channel parts to form a required number of channels. Each channel part is formed by stacking two kinds of annular magnetic rings so that two rings having the same outside and inside diameters are placed at both sides of a ring having the same inside diameter as the two rings but a greater outside diameter than the two rings. A stator core is also formed by stacking channel parts to form the required number of channels. The channel part is formed by stacking two kinds of annular magnetic rings so that two rings having the same outside and inside diameters are placed on both sides of a ring having the same inside diameter with the two rings but smaller outside diameter than the two rings. A thin layer of glass can be used to bond the rings of the stator or rotor together.