JP2009267223A - Inductance element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inductance element for miniaturization, weight reduction and price-reduction by improving damping characteristic in a low frequency band by lowering self resonance frequency of the inductance element without changing material of a magnetic core, outside dimension and the number of turns of a coil, etc. <P>SOLUTION: In a structure of the inductance element, the whole magnetic core 15 is covered with an insulating case 16, conductors 19a and 19b are arranged at two points of an outer peripheral surface of the insulating case 16, respectively. While one dielectric material 21a is so arranged as to cover the upper surface of the periphery of both the conductors 19a and 19b, coils 17 and 18 are formed by winding coated wires symmetrically on a semicircle portion of the periphery on the outside of the dielectric material so as to surround the conductors 19a and 19b, respectively. The conductor 19a and the coil 17 are electrically connected at a connection part 20a, and the conductor 19b and the coil 18 are electrically connected at a connection part 20b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inductance element used in a noise filter that is inserted between an AC power supply line and various electronic devices and removes electromagnetic noise due to conduction or radiation.

FIG. 5 is a typical equivalent circuit diagram of a noise filter using an inductance element inserted between an AC power supply line and a switching power supply input unit of various electronic devices.
The noise filter 1 includes a pair of a capacitor element 13 and an inductance element 14 for removing common mode noise, and a capacitor element 11 and an inductance element 12 for removing differential mode noise. Each of these elements is used in combination with the arrangement, connection, etc. according to the noise level of the electronic device, and the number of each element used is increased or decreased depending on the noise level.
The differential mode noise is the noise that flows between the two AC power supply lines of the noise filter 1, and the common mode noise is the noise that flows between the two AC power supply lines of the noise filter 1 and the ground in the same phase. Say each.

  The inductance elements 12 and 14 are different in the number of coils formed on the outer periphery of the magnetic core. The inductance element 12 has one coil, whereas the inductance element 14 has two coils. Also, the inductance element 12 is different in characteristics in that it has the function of removing the differential mode noise, while the inductance element 14 is responsible for removing the common mode noise.

In general, an inductance element has a self-resonant frequency fr = 1 / 2π (LC) ^1/2 determined by the inductance L and the line-to-line capacitance C of the coil itself, and has an inductance in a frequency region lower than the self-resonant frequency fr. On the other hand, it has a property of acting as a capacitor element in a frequency region higher than the self-resonant frequency fr. Accordingly, in order to remove various frequency noises, the inductance L and the line capacitance C are appropriately adjusted while adjusting the material and outer dimensions of the magnetic core, the number of turns of the coil, the winding structure, and the like. Controls noise attenuation characteristics.

  6A and 6B are diagrams for explaining the structure of the inductance element in the case where there are two coils among the inductance elements constituting the noise filter 1 described above. FIG. 6A is a front view, and FIG. 6B is a cross-sectional view. Respectively. In the conventional inductance element 61, a dielectric 64 and a proximity conductor 65 are sequentially formed on a ground conductor 63 disposed so as to cover the entire surface of the toroidal magnetic core 62, and the circumference of the outer periphery thereof is further increased. In this structure, a coil 67 and a coil 68 are formed by winding a coated conductive wire 66 symmetrically so as to surround the proximity conductor 65 in a semicircular portion. The ground conductor 63 is grounded via the lead wire 69 to reduce the line capacitance generated between the coils 67 and 68.

  With this configuration, the attenuation characteristic in a higher frequency region than the self-resonant frequency of the inductance element 61 is improved, the attenuation characteristic is widened, and the magnetic core 62 and the coated conductor 66 are structurally separated. Therefore, their insulating properties are also improved. Such an inductance element is disclosed in Patent Document 1, for example.

JP 2004-235709 A

  However, the conventional inductance element 61 reduces the line capacitance of the coil by grounding the magnetic core 62 and the ground conductor 63 and improves the attenuation characteristics in a frequency band higher than the self-resonance frequency. It did not improve the attenuation characteristics in a frequency band lower than the resonance frequency. In order to improve the attenuation characteristics in such a low frequency band, there are only methods such as increasing the magnetic permeability μ and outer dimensions of the magnetic core or increasing the number of turns of the coil. As a result, the size of the inductance element is reduced. There is a problem that the coil loss (heat generation) increases due to the increase in the number of turns and the number of turns.

  The present invention improves the attenuation characteristics in the low frequency band by lowering the self-resonance frequency of the inductance element without changing the material, outer dimensions and the number of turns of the magnetic core. An object of the present invention is to provide an inductance element that can be reduced in price.

In order to solve the above problems, the present invention forms a capacitor between coils formed on the outer periphery of the magnetic core of the inductance element. In other words, a conductor and a dielectric are arranged, and the conductor is electrically connected to the coil instead of being grounded to the earth, thereby increasing the line capacitance generated between the coils and the inductance element. Thus, it is possible to improve the noise attenuation characteristic in the low frequency region by lowering the self-resonance frequency of the low frequency band. As a result, the attenuation characteristic in the low frequency band can be improved.
Further, the number of coils may be one or more. In that case, the conductor is arranged independently in each coil. In addition, the same effect can be obtained by using a capacitor element containing a conductor and a dielectric. However, in this case, the attenuation characteristics in the low frequency band are improved by connecting the both ends of the coil in parallel. It becomes possible to do.

  According to the present invention, a magnetic core, a coil formed by winding a coated conductive wire around the magnetic core, a conductor electrically insulated from the magnetic core, and a dielectric, the coil and the conductor are provided. An inductance element is obtained in which the dielectric is disposed between the conductors, and the conductor is electrically connected to the coil.

  According to the present invention, it is possible to obtain an inductance element including one or more of the coil and the conductor, wherein one or more of the conductors are independently arranged in each of the coils.

  According to the present invention, an inductance comprising: a magnetic core; a coil formed by winding a coated conductor around the magnetic core; and a capacitor element, wherein the capacitor element is connected in parallel to both ends of the coil. An element is obtained.

  According to the present invention, it is possible to obtain an inductance element having one or more coils and having capacitor elements connected in parallel at both ends of each of the coils.

  According to the present invention, an inductance element is obtained in which the magnetic core is annular.

  As described above, according to the present invention, a conductor that forms a capacitor through a dielectric is provided between a coil in which a coated conductor is wound around a magnetic core, and a part of the conductor is connected to the coil. A new self-resonant frequency can be achieved by reducing the self-resonance frequency while maintaining the rising characteristics of the impedance by using an inductance element or an inductance element with a capacitor element connected in parallel to both ends of a coil with a coated conductor wound around a magnetic core. In the nearby band, it is possible to improve the performance by increasing the impedance.

  In addition, since the attenuation characteristic in the low frequency region can be improved by lowering the self-resonance frequency of the inductance element while keeping the material and the number of turns of the magnetic core as it is, conventionally, for example, an inductance element for a low frequency and an element for a high frequency are used. Although two capacitor elements are required, the same noise suppression effect can be obtained with one inductance element, and it is possible to reduce the size, weight, and cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The inductance element in the embodiment described below has a structure in which two coils for winding a coated conductor are symmetrically formed on two semicircular portions of a common core, that is, a toroidal magnetic core. Applicable to normal mode in which only one coil is formed by winding a coated conductor around the circumference, or in the case of an inductance element in which three or more coils are formed.

  FIG. 1 is a front view illustrating an inductance element according to Example 1 of the invention.

The inductance element 14a covers the entire toroidal magnetic core 15 with a toroidal insulating case 16, and conductors 19a and 19b are arranged at two locations on the outer peripheral surface of the insulating case 16, respectively. In a state where one dielectric 21a is arranged so as to cover both the upper surfaces in a row, the coated conductors are symmetrically provided so as to surround the conductors 19a and 19b in a semicircular portion of the circumference of the outer periphery thereof. A coil 17 and a coil 18 are formed. Moreover, the conductor 19a and the coil 17 are electrically connected by the connection part 20a, and the conductor 19b and the coil 18 are electrically connected by the connection part 20b, respectively.
Here, one dielectric 21a is disposed so as to cover the entire conductors 19a, 19b arranged separately, but two dielectrics 21a may be disposed so as to individually cover each of the conductors 19a, 19b. . The conductors 19a, 19b and the dielectric 21a are disposed inside the coils 17, 18, but may be disposed outside the coils 17, 18, that is, after the coils 17, 18 are formed. In that case, it is preferable to dispose a dielectric 21a on the upper surface of the coils 17 and 18 and arrange conductors 19a and 19b on the upper surface of the dielectric 21a.

  FIG. 2 is a front view for explaining an inductance element according to the second embodiment of the present invention.

The inductance element 14b covers the entire toroidal-shaped magnetic core 15 with a toroidal-shaped insulating case 16, and symmetrically arranges conductors 19c and 19d on the side surface of the insulating case 16 in a semicircular portion of the circumference. In a state where the dielectrics 21b and 21c are arranged so as to cover the entire upper surface of each of the conductors 19c and 19d, the conductors 19c and 19d are surrounded by the semicircular part of the circumference of the outer periphery. A coil 17 and a coil 18 are formed by winding the coated conductors symmetrically. Further, the conductor 19c and the coil 17 are electrically connected by the connecting portion 20c, and the conductor 19d and the coil 18 are electrically connected by the connecting portion 20d.
Here, the conductors 19c and 19d and the dielectrics 21b and 21c are arranged on one side surface of the insulating case 16, but may be arranged on the other side surface and other surfaces in the same manner. A conductor may be formed on the inner surface of the insulating case 16 as a dielectric. However, the positional relationship between the conductor and the dielectric is preferably such that the conductor is completely covered with the dielectric and not exposed to the surface.
The conductors 19c, 19d and the dielectrics 21b, 21c are disposed inside the coils 17, 18, but may be disposed outside the coils 17, 18, that is, after the coils 17, 18 are formed. In this case, it is preferable to dispose the dielectric 21a on the upper surface of the coils 17 and 18 and arrange the conductors 19a and 19b on the upper surface of the dielectric 21a.

  FIG. 3 is a front view for explaining an inductance element according to the third embodiment of the present invention.

  The inductance element 14c includes a coil 17 in which the entire toroidal magnetic core 15 is covered with a toroidal insulating case 16, and a coated conductor is wound symmetrically around a semicircular portion of the circumference of the outer peripheral portion of the insulating case 16, A coil 18 is formed, and capacitor elements 22a and 22b are connected in parallel to both ends of each coil.

  The magnetic core 15 may be any material as long as the material is a magnetic material having a high magnetic permeability, such as a Mn—Zn-based or Ni—Zn-based ferrite material, a metal-based material such as amorphous or permalloy, an iron-based or iron alloy-based material, In addition, a compacted material made of a conductive material such as metal powder may be used, and it is preferable to select appropriately according to required characteristics. Further, the outer shape may be any shape such as a circle, an ellipse, and a rectangle, and the cross-sectional shape may be any shape such as a circle, an ellipse, an oval, and a polygon.

  The insulating case 16 may be any material as long as it is a resin material that covers the magnetic core 15 in an insulating manner, such as an epoxy-based or phenol-based thermosetting resin, polypropylene (PP), polystyrene (PS), or polybutylene terephthalate (PBT). Any of nylon thermoplastic resins may be used. Further, the form is not limited to the above-mentioned resin molded body, and an insulating form in which insulating paper or the like is wound around the magnetic core 15 to a certain thickness may be used.

  The coils 17 and 18 may be made of any enamel-coated copper wire obtained by baking a natural resin or synthetic resin paint on a conductor, or any conductive wire such as a PVC-covered electric wire with improved insulation. It is preferable to design and adjust appropriately according to the required characteristics.

  The conductors 19a, 19b, 19c, and 19d may be any material as long as the material is conductive, such as a metal material such as copper, aluminum, and stainless steel, or an alloy thereof, or a metal resin obtained by mixing metal powder and resin. Good. Further, the shape is preferably a plate shape or a foil shape, and may be a lattice shape or a mesh shape. Further, the arrangement position may be a part or the whole of the outer peripheral portion of the magnetic core 15, inside the coils 17, 18, or outside the coils 17, 18. The arrangement state is arranged so as not to directly contact the coils 17, 18. It is sufficient that the entire surface is covered with a dielectric.

  The connecting portions 20a, 20b, 20c, and 20d are preferably any one portion of the coil, and any one of the ends such as the start of winding and the end of winding.

The dielectrics 21a, 21b, and 21c may be any resin as long as it has a dielectric constant, but a general-purpose thermoplastic resin such as polyethylene terephthalate (PET) that can be arbitrarily bent in operation may be used. It is more preferable to select one having a high dielectric constant in order to increase the inter capacitance.
Further, it is preferable to adjust the thickness as appropriate in consideration of the capacitance between the lines, but it is more preferable to use a thin film that can increase the capacitance between the lines and suppress the outer dimensions of the inductance element. .

  Capacitor elements 22a and 22b may be any type of capacitor such as electrolysis, film, or multilayer ceramic.

Hereinafter, it explains in full detail using an Example.

Example 1
As the magnetic core 15, a Mn—Zn ferrite material was used, and the shape was a toroidal shape with an outer diameter of 25 mm, an inner diameter of 15 mm, and a height of 12 mm. As the insulating case 16, a molded body made of PBT resin and having an outer diameter of φ27 mm, an inner diameter of φ13 mm, a height of 14 mm, and a thickness of 0.5 mm was used to house the magnetic core 15. Conductors 19a and 19b made of copper foil and having a length of 20 mm and a width of 10 mm are arranged on the outer peripheral surface of the insulating case 16, and a polyethylene terephthalate (PET) having a thickness of 0.5 mm, a width of 12 mm, and a length of 70 mm is disposed on the outside. A dielectric 21a made of resin is arranged so as to cover both the conductors 19a and 19b.
As the coils 17 and 18, polyurethane-coated copper wires (UEW wires) having a wire diameter of φ0.8 mm are used, and symmetrical windings are performed on the semicircular portions of the outer peripheral portion of the insulating case 16 including the dielectric 21a, The number of turns was 38 turns. After forming the coil, the coil 17 and the conductor 19a are connected by soldering at the connecting portion 20a, and the coil 18 and the conductor 19b are connected by soldering at the connecting portion 20b, respectively, and the inductance according to the first embodiment of the present invention shown in FIG. Element 14a was obtained. Here, the conductors 19a and 19b other than the connecting portions 20a and 20b are not exposed from the surface of the dielectric 21a.

(Example 2)
In addition, when the arrangement positions of the conductors 19c and 19d are changed using the same members as in the first embodiment, that is, the conductors 19c and 19d are arranged on the side surfaces of the surface of the toroidal insulating case 16, and the entire conductors are arranged on the upper surface. The inductance element 14b according to the second embodiment of the present invention shown in FIG. 2 in which the dielectrics 21b and 21c are arranged so as to cover is obtained.

(Example 3)
Further, the same members as in Example 1 are used, the conductor and the dielectric are deleted, and capacitor elements 22a and 22b are provided at both ends of the coils 17 and 18, respectively, as a multilayer ceramic capacitor. An inductance element 14c according to Example 3 of the present invention shown in FIG. 3 was obtained, which had a size of 3 mm × 2 mm and a capacity of 10 pF, both connected in parallel.

  In any of the cases described above, the characteristics of the inductance element can be adjusted by adjusting the area where the conductor and the coil face each other, the thickness and material of the intervening dielectric, or the capacitance of the capacitor element.

  Inductors 14a, 14b, and 14c according to Examples 1 to 3 of the present invention shown in FIGS. 1, 2, and 3 manufactured in the above manner and the same member as a comparative example are used. For each of the conventional inductance elements 61 shown in FIG. 4, the respective attenuation characteristics were measured, and the comparison results are shown in FIG.

  As shown in FIG. 4, the inductance elements 14a, 14b, and 14c of the present invention lower the self-resonance frequency while maintaining the rise characteristic of the impedance as compared with the conventional inductance element 61, and impedance in a band near the new self-resonance frequency. A good damping characteristic due to the increase of the is obtained.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to these embodiments, and the present invention is not limited to the scope of the present invention. Included in the invention. That is, various changes and modifications that can be naturally made by those skilled in the art are also included in the present invention.

  The inductance element of the present invention can contribute not only to the high performance (broadband) of noise filters mounted on various electronic devices, but also to the construction of EMC and EMI markets that can be reduced in size and cost.

The front view explaining the inductance element by Example 1 of this invention. The front view explaining the inductance element by Example 2 of this invention. The front view explaining the inductance element by Example 3 of this invention. The attenuation characteristic comparison figure of the inductance element of this invention and the conventional inductance element. The equivalent circuit diagram of a noise filter. The figure explaining the structure of the conventional inductance element, Fig.6 (a) is a front view, FIG.6 (b) is sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Noise filter 11, 13 Capacitor element 12 Inductance element 14, 14a, 14b, 14c Inductance element 15 Magnetic core 16 Insulation case 17, 18 Coil 19a, 19b, 19c, 19d Conductor 20a, 20b, 20c, 20d Connection part 21a, 21b, 21c Dielectric 22a, 22b Capacitor element 61 Inductance element 62 Magnetic core 63 Ground conductor 64 Dielectric 65 Proximity conductor 66 Coated conductor 67, 68 Coil 69 Lead wire

Claims (5)

  A magnetic core; a coil formed by winding a coated conductive wire around the magnetic core; a conductor electrically insulated from the magnetic core; and a dielectric; and the dielectric between the coil and the conductor An inductance element, wherein the conductor is electrically connected to the coil.   The inductance element according to claim 1, comprising at least one of the coil and the conductor, wherein one or more of the conductors are independently arranged on each of the coils.   An inductance element comprising: a magnetic core; a coil formed by winding a coated conductor around the magnetic core; and a capacitor element, wherein the capacitor element is connected in parallel to both ends of the coil.   The inductance element according to claim 3, wherein the inductance element includes one or more coils, and capacitor elements are connected in parallel to both ends of each of the coils.   The inductance element according to claim 1, wherein the magnetic core is annular.

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