JP2009021325A - Winding type common mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a winding type common mode choke coil which can be improved in degree of balance between a plurality of windings. <P>SOLUTION: The winding type common mode choke coil 10 includes a magnetic core 11 having a core portion 11A and collar portions 11B at both ends thereof, first and second windings 12 and 13 wound around the core portion 11A vertically one over the other, and a plurality of electrodes (not shown) which are formed at the collar portions 11B and to which both end portions of the windings 12 and 13 are electrically connected, and the first and second windings 12 and 13 have conductor wires 12A and 13B, ferromagnetic coatings 12B and 13B covering the conductor wires 12A and 13A, and insulating resin coatings 12C and 13C covering the ferromagnetic coatings 12B and 13B. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a wire wound common mode choke coil having at least two windings,
More specifically, the present invention relates to a wound common mode choke coil that can increase the balance between at least two windings.

  A conventional wire wound common mode choke coil includes, for example, a magnetic core having a winding core and a pair of flanges formed at both ends thereof, two windings wound around the winding core, And a plurality of electrodes respectively provided on a pair of flanges, and inserted into a transmission line to be used for reducing a noise level of a transmission signal and preventing signal waveform deterioration. This type of wire wound common mode choke coil has been proposed in many patent documents.

  For example, Patent Document 1 proposes a wound common mode choke coil in which a winding is concentrically wound around a winding core portion and the diameter is expanded in a spiral shape. Thus, the winding type common mode choke coil can be reduced in height by winding the windings in a spiral shape.

  Further, Patent Document 2 proposes a coil component in which two windings are substantially uniformly wound in two layers on the entire core portion. This coil component is used as, for example, a common mode choke coil. The coil component winding structure itself is conventionally known, but this coil component has an improvement in the structure for fixing the winding to the terminal electrode.

  Patent Document 3 proposes a wound common mode choke coil using a winding in which a conductor wire such as copper is sequentially covered with a ferromagnetic layer and an insulating material layer. In this winding type common mode choke coil, the winding is a single layer winding, but the conductor wire and the ferromagnetic layer constituting the winding are limited to specific dimensions. The common mode impedance characteristic of the electronic device is improved, and it is effective as a countermeasure against common mode noise of electronic devices compatible with the interface IEEE1394, USB 2.0 and the like. As the winding, a single wire and a pair wire obtained by integrating a pair of parallel single wires are used. The same type of single-wire winding as used here has already been proposed in the coil device of Patent Document 4.

  As shown in Patent Documents 1 and 2, the wound common mode choke coil can achieve high common mode impedance by overlapping two windings, realizing low profile and miniaturization. can do. For example, when winding two windings in the coil component of Patent Document 2, as shown in FIG. 3, a pair of left and right ridges 3 (on the left side in the figure) with respect to the core portion 2 of the magnetic core 1. The first coil layer 4A is formed by winding the winding 4 between the first and second ribs), and then the second winding coil layer is wound on the coil layer 4A. 4B is formed.

JP 2004-179314 A JP2006-121013 JP2002-110428 JP 05-1212237 A

  However, since the conventional wound common mode choke coil has a two-layer structure in which two windings 4 are vertically stacked as shown in FIG. 3, the first coil layer 4A has a core portion. 2, the second coil layer 4 </ b> B is distant from the core 2. In this case, since the magnetic core 1 exhibits high permeability to air, the magnetic permeability around the coil layer 4A near the core 2 and the permeability around the coil layer 4B far from the core 2 are different. As a result, the normal mode inductances in the coil layers 4A and 4B are different. Therefore, the first coil layer 4A and the second coil layer 4B have different responses to input signals, and the balance of the coil layers 4A and 4B deteriorates. When this winding type common mode choke coil is used in, for example, a differential transmission circuit, the normal mode signal is converted into common mode noise due to the unbalance of the coil layers 4A and 4B, and the noise level increases. It will be.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wound common mode choke coil capable of improving the balance of upper and lower windings.

  According to a first aspect of the present invention, there is provided a wound common mode choke coil having a core part and a magnetic core having flanges at both ends thereof, and at least two wound around the core part one above the other. A winding-type common mode choke coil comprising a plurality of windings and a plurality of electrodes formed on the flange and electrically connected to both ends of each winding. It has a conductor wire serving as a core wire, a ferromagnetic layer covering the conductor wire, and an insulator layer covering the magnetic layer.

  According to claim 2 of the present invention, in the wire wound common mode choke coil according to claim 1, the magnetic layer is made of iron or an iron-nickel alloy. .

  A winding type common mode choke coil according to claim 3 of the present invention is used in a transmission line of an automobile control system in the invention according to claim 1 or claim 2.

  ADVANTAGE OF THE INVENTION According to this invention, the winding type common mode choke coil which can improve the balance between windings can be provided.

  Hereinafter, the present invention will be described based on the embodiment shown in FIGS. In each figure, FIGS. 1A and 1B are views showing the main part of one embodiment of the wound common mode choke coil of the present invention, and FIG. ) Is a cross-sectional view showing an enlarged cross-sectional structure of the winding, and FIG. 2 is a graph showing a comparison of the balance between the winding-type common mode choke coil shown in FIG. 1 and the conventional winding-type common mode choke coil.

  As shown in FIG. 1A, for example, the winding type common mode choke coil 10 of the present embodiment includes a winding core portion 11A and a pair of flange portions 11B formed at both ends thereof (only the left flange portion is illustrated. And a magnetic core 11 (for example, a ferrite core) having two and first and second insulating coatings that are wound so as to form a coil layer above and below the core portion 11A. A plurality of terminal electrodes (not shown) formed on the pair of left and right flanges 11B and electrically connected to both ends of each of the windings 12 and 13; Both ends of the first and second windings 12 and 13 wound around 11A are connected to the electrodes of the pair of flange portions 11B and 11B, respectively, and are configured as, for example, a common mode choke coil for differential signals. .

  A plate-like core 14 made of a magnetic material or a non-magnetic material is joined to the upper surfaces of the pair of flange portions 11B and 11B. By joining the plate-like core 14 between the pair of flanges 11B, 11B, a closed magnetic circuit is formed in the magnetic core 11, the common mode inductance can be increased, and the noise removal performance and the signal waveform shaping effect are enhanced. Can do. Furthermore, since the upper surface is flattened by the plate-like core 14, for example, the winding type common mode choke coil 10 can be easily picked up, and its mounting workability can be improved.

  The first winding 12 is directly wound around the winding core portion 11A to form a first coil layer, and the second winding 13 is wound around the surface of the first coil layer to form a second coil layer. It is formed as. Since the first coil layer is close to the core portion 11A made of ferrite with high magnetic permeability and the second coil layer is farther from the core portion 11A than the first coil layer, the first winding The degree of balance between 12 and the second winding 13 is degraded.

  However, in the present embodiment, the first and second windings 12 and 13 use a wire having a ferromagnetic layer as shown in FIG. 1B, and the magnetic flux concentrates on the ferromagnetic layer. The normal mode inductances of the lines 12 and 13 are made substantially equal. Since the first and second windings 12 and 13 are formed of the same wire material, the first winding 12 will be described below.

  As shown in FIG. 1B, the first winding 12 includes a conductor wire 12A, a ferromagnetic layer 12B covering the conductor wire 12A, and an insulator layer covering the ferromagnetic layer 12B. 12C. The conductor wire 12A is preferably formed of, for example, copper or a copper alloy, and the ferromagnetic layer 12B is preferably formed of, for example, a plating layer of iron or an iron-nickel alloy. The insulator layer 12C is preferably formed of a thermosetting resin such as a polyurethane resin, a polyester resin, or a polyimide resin. A metal layer may be formed between the ferromagnetic layer 12B and the insulator layer 12C.

  In the first and second windings 12 and 13 of this embodiment, the surface of the conductor wire 12A is covered with the ferromagnetic layer 12B as described above, and magnetic flux is applied to each of the ferromagnetic layers 12B and 14B. Concentrated, the normal mode inductances of the windings 12 and 13 become substantially equal, and as a result, the balance between the first and second windings 12 and 13 is improved.

For example, FIG. 2 shows that the winding type common mode choke coil 10 of the present embodiment and a conventional winding type common mode choke coil having no ferromagnetic layer are inserted into the differential transmission lines, and the respective S parameters are measured. It is a graph which shows the result of having investigated the transmission characteristic. In the figure, the solid line shows the wound common mode choke coil of this embodiment, and the broken line shows the conventional one. The following was used as the winding type common mode choke coil 10 of the present embodiment. The conventional one is substantially the same as that of the present embodiment except that there is no ferromagnetic layer.
Coil dimensions: Length 4.5mm x width 3.2mm x height 2.6mm
Winding diameter: 90 μm
Winding conductor wire: copper having a diameter of 64 μm Winding ferromagnetic layer: iron having a thickness of 3 μm Winding insulator layer: polyurethane resin having a thickness of 10 μm Number of windings: 29

  According to the results shown in FIG. 2, the winding type common mode choke coil of this embodiment has improved balance as compared with the conventional one, and the common mode noise with respect to the normal mode signal in the high frequency band of 1 to 100 MHz. It can be seen that the output can be greatly reduced. Since the wound common mode choke coil 10 of the present embodiment exhibits such characteristics, it can be suitably used for FlexRay, which is a LAN interface standard used for driving control of automobiles, for example, and improves the control characteristics of automobiles. Can be made.

  As described above, according to the present embodiment, the wound common mode choke coil 10 includes the core portion 11A and the magnetic core 11 having the flange portions 11B at both ends thereof, and the top and bottom layers of the core portion 11A. And a plurality of terminals formed on the flange portion 11B and electrically connected to both ends of the first and second windings 12 and 13, respectively. Electrodes (not shown), and the first and second windings 12 and 13 are conductor wires 12A and 13A serving as core wires, and ferromagnetic layers 12B and 13B covering the conductor wires 12A and 13A. And the insulator layers 12C and 13C covering the ferromagnetic layers 12B and 13B, the distance between the first and second windings 12 and 13 and the high magnetic permeability core portion 11A Even if there is a magnetic field, the magnetic layers 12B and 13B of the windings 12 and 13 are magnetized. There concentrate, each of the normal mode inductance becomes substantially equal, first, the degree of balance between the second winding 12, 13 is improved. As a result, the winding type common mode choke coil 10 of the present embodiment can suppress the conversion of the normal mode signal into common mode noise when used in a differential transmission circuit.

  Further, according to the present embodiment, the first and second windings 12 are formed by forming the ferromagnetic layers 12B and 13B of the first and second windings 12 and 13 from iron or iron-nickel alloy. , 13 can be reliably improved. Further, by using the wire wound common mode choke coil 10 of the present embodiment for FlexRay, which is a LAN interface standard used for driving control of an automobile, for example, the control characteristics of the automobile can be improved.

  In addition, this invention is not restrict | limited to the said embodiment at all. For example, in each of the above embodiments, the winding structure of the winding is a two-layer structure, but may be a three-layer structure or more if necessary. In the above embodiment, the windings 12 and 13 have been described as having conductor wires 12A and 13A as core wires, ferromagnetic layers 12B and 13B, and insulator layers 12C and 13C. These layers may be interposed. Further, the magnetic core is not limited to the ferrite core. The point is that it is a wound common mode choke coil in which at least two windings are vertically wound around the core of the magnetic core, and the winding has a conductor wire, a magnetic layer and an insulator layer. Are encompassed by the present invention.

  The present invention can be suitably used for a wound common mode choke coil used in electronic equipment such as automobiles and communication equipment.

(A), (b) is a figure which shows the principal part of one Embodiment of the winding type common mode choke coil of this invention, respectively, (a) is sectional drawing of a right half, and the figure which expands and shows the cross section of a coil | winding It is. It is a graph which shows the balance of the winding type common mode choke coil shown in FIG. 1 in comparison with a conventional winding type common mode choke coil. It is sectional drawing equivalent to FIG. 1 which shows an example of the conventional winding type common mode choke coil.

Explanation of symbols

10 Wound-type common mode choke coil 11 Ferrite core (magnetic core)
11A winding core part 11B collar part 12, 13 winding 12A, 13A conductor wire 12B, 13B ferromagnetic layer 12C, 13C insulator layer

Claims (3)

  A magnetic core having a winding core portion and flange portions at both ends thereof, at least two windings wound vertically on the winding core portion, and formed on the flange portion and each of the windings A winding-type common mode choke coil having a plurality of electrodes electrically connected at both ends, wherein the winding includes a conductor wire serving as a core wire and a ferromagnetic layer covering the conductor wire And a wire-wound common mode choke coil comprising: an insulating layer covering the magnetic layer.   2. The wound common mode choke coil according to claim 1, wherein the magnetic layer is made of iron or an iron-nickel alloy.   The wound common mode choke coil according to claim 1 or 2, wherein the wound common mode choke coil is used for a transmission line of an automobile control system.

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