JP6604917B2 - Common mode choke coil - Google Patents

Description

  The present invention relates to a common mode choke coil that is provided in a noise filter and removes noise.

  Conventionally, a noise filter composed of a common mode choke coil and a capacitor is a device that prevents an electronic device from malfunctioning due to noise entering the electronic device from the outside via a power line, a communication line, etc. Essential for equipment.

  7, the common mode choke coil 100 used for the noise filter has a toroidal core housed in a resin case 102, and a pair of windings 104a on the core resin case 102 covering the toroidal core. , 104b are wound so that the magnetic fluxes cancel each other with respect to the normal mode current, and the terminal 108 is attached to the pedestal 106 taken out.

  FIG. 8 shows a noise filter circuit using a common mode choke coil. A common mode choke coil 100 is interposed between the AC input terminals 110a and 110b and the AC output terminals 112a and 112b, and an interphase capacitor 114 is interposed between the lines. Each line is grounded by an FG terminal via a grounding capacitor 116. The common mode choke coil 100 is connected between the AC input terminals 110a and 110b and the AC output terminals 112a and 112b to attenuate low-frequency common mode noise.

  The interphase capacitor 114 is connected between the input side and output side lines of the common mode choke coil 100 and mainly attenuates low-frequency normal mode noise. The grounding capacitor 116 is connected between the line and the ground to mainly attenuate high-frequency common mode noise.

JP 2012-100002 A JP 2002-057047 A

  However, in such a conventional common mode choke coil, the directions of the windings 104a and 104b wound around the toroidal core are not in one direction but in many directions. Since the structure is easy to receive, there is a problem that the magnetic flux from the outside is converted into current by the windings 104a and 104b and flows to the AC power supply line as noise.

  FIG. 8A shows the case where the external magnetic flux 120 jumps evenly into the windings 104a and 104b of the common mode choke coil 100. The direction of the current generated in the windings 104a and 104b by the magnetic flux 120 is the normal mode current i1. And flows to the AC power line.

  FIG. 8B shows a case where the magnetic flux 120 from the outside jumps into one winding 104 a of the common mode choke coil 100 and the balance of the magnetic flux jumping into the windings 104 a and 104 b is lost. The direction of the generated current becomes a common mode current i2 and flows to the AC power supply line.

  Measures against this problem, such as covering the periphery with a ferromagnetic material so that magnetic flux does not enter the common mode choke coil, moving away from the source of magnetic flux, and increasing the capacitance of the interphase capacitor or grounding capacitor However, it has caused problems such as cost increase of parts materials and enlargement of product outer shape.

  Further, as a conventional technique, there is a technique in which a leakage magnetic flux generated by a common mode choke coil itself is absorbed by a strip-shaped magnetic shield member provided along the direction of the leakage magnetic flux (Patent Document 2).

  However, in the structure in which a part of the common mode choke coil is covered with the magnetic shield, when the magnetic flux from the outside jumps into the winding portion exposed from the magnetic shield, the conventional common mode shown in FIGS. 7 and 8 is used. Similar to the choke coil 100, there is a problem that the jumped magnetic flux is converted into a current and flows as a noise current in the AC power supply line.

  It is an object of the present invention to provide a common mode choke coil that can reduce the influence of magnetic flux jumping from the outside without increasing the cost and increasing the size of the product.

(Common mode choke coil)
The present invention provides a common mode choke coil in which a pair of windings arranged symmetrically so that magnetic fluxes cancel each other with respect to a normal mode current are wound on a resin case covering a toroidal core.
A conductor is arranged in a loop shape surrounding a toroidal core around which a pair of windings are wound.

(Disposition relationship between toroidal core and conductor)
In the conductor, the axis of the conductor loop is orthogonal to the axis of the toroidal core, and the axis of the conductor is symmetrical to the symmetry axis of the pair of windings orthogonal to the axis of the toroidal core. arranged substantially becomes parallel, and the winding by flowing an induced current in the conductor loop by an external magnetic field from the axial line in the same direction of the conductor loop to be shielded.

(Conductor material)
The conductor is made of a non-ferromagnetic metal.

(Copper foil tape)
The conductor is a copper foil tape, and is affixed to the outside of an insulating resin case including an insulating tape disposed around the toroidal core, and the tape ends are electrically joined.

(Copper plate or copper foil)
A conductor is a copper plate or copper foil, and is arrange | positioned on the outer side of the rectangular resin case arrange | positioned surrounding the toroidal core.

(Basic effect)
The present invention relates to a common mode choke coil in which a plurality of windings are wound around a resin case covering a toroidal core so that magnetic fluxes cancel each other out with respect to a normal mode current. Since the conductor is arranged in a loop around the toroidal, when a magnetic flux from the outside jumps into the conductor, it is converted into an induced current by the conductor, and a loop current flows, thereby the magnetic flux reaching the winding Is weakened, and the noise current flowing in the AC power supply line can be reduced. Further, since it is only necessary to arrange the conductor in a loop around the toroidal core, the structure is simple, and problems such as an increase in the cost of component materials and an increase in the size of the product can be suppressed.

(Effects of the arrangement relationship between the toroidal core and the conductor)
The conductor is arranged so that the axis of the conductor loop is orthogonal to the axis of the toroidal core, and an induced current is applied to the conductor loop by an external magnetic field from the same direction as the axis of the conductor. Since it is configured to shield the winding by flowing it, it effectively converts it into a loop current when an external magnetic field jumps in the same direction as the axis of the conductor, weakening the influence of the magnetic flux on the winding, and the AC power line The noise current flowing through the can be reduced.

(Effects of conductor material)
In addition, since the conductor is made of a highly conductive non-ferromagnetic material such as copper, the magnetic flux applied to the winding can be converted by efficiently converting the magnetic flux received from the outside into an induced current flowing in the conductor loop. It is possible to weaken the influence of.

(Effects of copper foil tape)
In addition, the conductor is a copper foil tape, and the end of the tape is electrically bonded by being attached to the outside of the insulator including the insulating tape arranged around the toroidal core. This can be realized by a simple structure in which a copper foil tape is wound around a resin case disposed outside the housing, and problems such as an increase in the cost of component materials and an increase in the size of the product outer shape can be suppressed.

(Effects of copper plate or copper foil)
In addition, the conductor is a copper plate or copper foil, and is arranged outside the rectangular resin case arranged around the toroidal core, so that the copper plate is placed outside the resin case arranged outside the toroidal core. As in the case of the copper foil tape, it is possible to suppress problems such as an increase in the cost of component materials and an increase in the outer shape of the product.

Explanatory drawing which showed 1st Embodiment of the common mode choke coil using the copper foil tape as a conductor from the front and the side Explanatory drawing which showed the example of the manufacture assembly of embodiment of FIG. Explanatory drawing which showed the 2nd embodiment of the common mode choke coil which used the copper plate as a conductor from the front and the side. Explanatory drawing which showed the assembly disassembly state of embodiment of FIG. Explanatory drawing which took out the resin case which has arrange | positioned the copper plate of FIG. Explanatory drawing which showed 3rd Embodiment of the common mode choke coil which has arrange | positioned the toroidal core sideways Explanatory drawing showing a conventional common mode choke coil from the front and side Circuit diagram showing noise filter circuit using common mode choke coil

[First embodiment of common mode choke coil]
FIG. 1 is an explanatory view showing a first embodiment of a common mode choke coil using a copper foil tape as a conductor from the front and side.

  As shown in FIG. 1A, in the common mode choke coil 10 of this embodiment, a pair of windings 18a and 18b are wound around a pedestal 12 having terminals 14, and a toroidal core is provided inside. The stored core resin case 16 is attached. The windings 18a and 18b of the core resin case 16 are wound so that the magnetic fluxes cancel each other with respect to the normal mode current.

  A box-shaped resin case 20 that is opened up and down is disposed around the core resin case 16 of a toroidal core around which the windings 18a and 18b are wound. A loop-shaped conductor is disposed outside the resin case 20. As shown in FIG. 1 (B), the copper foil tape 22 is attached to the end portion of the copper foil tape 22 by a joining portion 24, and a strip-shaped conductor rectangle is formed. A loop shape is formed.

  Here, the copper foil tape 22 arranged in a loop shape passes through the center of the core of the core resin case 16, that is, the center of the toroidal core in the longitudinal direction and the center of the loop of the copper foil tape 22 in the longitudinal direction. When the axial center wire 30 is arranged so as to be orthogonal and receives an external magnetic flux 26 from the same direction as the axial center wire 30 at the center of the loop of the copper foil tape 22, an induced current flows through the loop of the copper foil tape 22. It is configured.

  Further, the copper foil tape 22 is made of a non-ferromagnetic material, and when a magnetic flux is received from a direction orthogonal to the conductor loop, an induced current flows through the conductor loop orthogonal to the magnetic flux. The energy is converted into an induced current flowing through the loop of the copper foil tape 22 to be weakened, and the windings 18a and 18b wound around the core resin case 16 disposed therein can be shielded from the external magnetic flux 26. Noise current flowing in the power supply line can be suppressed.

  FIG. 2 is an explanatory view showing an example of manufacturing and assembly of the embodiment of FIG. As shown in FIG. 2, in the manufacturing and assembly of the common mode choke coil 10 according to the present embodiment, a pair of windings 18a and 18b are wound around a pedestal 12 provided with terminals 14 in the same manner as in the past. A coil assembly 10a having a core resin case 16 containing a toroidal core is prepared, and a copper foil tape 22 is attached to the outside of the resin case 20 opened up and down, and the tape ends are joined by soldering or the like. And prepare.

  Subsequently, the resin case 20 to which the copper foil tape 22 is attached is fitted to the outside of the core resin case 16 in the coil assembly 10a and fixed to the pedestal 12 side.

  As described above, the present embodiment requires a simple structure in which the resin case 20 with the copper foil tape 22 attached is disposed outside the coil assembly 10a having the same configuration as that of the conventional common mode choke coil. Therefore, the cost is small and the outer shape of the product does not increase.

[Second Embodiment of Common Mode Choke Coil]
FIG. 3 is an explanatory view showing a second embodiment of a common mode choke coil using a copper plate as a conductor from the front and side, FIG. 4 is an explanatory view showing an assembled and disassembled state of the embodiment of FIG. 3, and FIG. It is explanatory drawing which took out the resin case which has arrange | positioned the copper plate of FIG. 4 in the outer periphery, and showed it from the front, the plane, and the side surface.

  As shown in FIG. 3, the common mode choke coil 10 of the present embodiment has a rectangular shape on the outside of the resin case 20 as a conductor arranged in a loop surrounding the outside of the core resin case 16 containing the toroidal core. The formed thin copper plate 28 is fitted. Instead of the copper plate 28, a rectangular copper foil may be fitted. Other configurations are the same as those of the first embodiment shown in FIG.

  As shown in FIG. 4, in the manufacture and assembly of the common mode choke coil 10 of this embodiment, the resin case 20 in which the copper plate 28 is fitted to the outside of the coil assembly 10a having the same configuration as that of the conventional common mode choke coil is provided. The arrangement is simple and the increase in component materials is small, so there is little increase in cost and the size of the product does not increase.

  Further, as shown in FIG. 5, the resin case 20 is a box-shaped case opened up and down, and a copper plate 28 is fitted in a loop shape so as to surround the outside of the resin case 20, and the cost is low because of the simple structure. The product outline is not enlarged.

[Third embodiment of common mode choke coil]
FIG. 6 is an explanatory view showing a third embodiment of a common mode choke coil in which a toroidal core is disposed horizontally.

  As shown in FIG. 6, the common mode choke coil 10 according to the present embodiment includes a core in which a pair of windings 18 a and 18 b are wound around a pedestal 12 including a terminal 14 and a toroidal core is accommodated therein. A resin case 16 is mounted horizontally.

A U-shaped resin case 32 which is open on the lower side surrounding the side and the upper side is fitted into the core resin case 16 of a toroidal core wound around the windings 18a and 18b placed horizontally on the pedestal 12. The copper foil tape 22 is wound around and pasted from the outside of the resin case 32 to the lower side of the pedestal 12, and, for example, the tape end located under the pedestal 12 is electrically joined by soldering or the like. Yes.

  Here, the copper foil tape 22 vertically arranged in a loop shape is transverse to the loop center of the copper foil tape 22 with respect to the axial center line passing through the center of the core resin case 16, that is, the center of the toroidal core. When the external magnetic flux 26 from the same direction as the axial center line 30 at the center of the loop of the copper foil tape 22 is received, an induced current is generated in the loop of the copper foil tape 22. As a result, the energy of the magnetic flux from the outside is converted into an induced current flowing through the loop of the copper foil tape 22 and weakened, and the windings 18a and 18b wound around the core resin case 16 disposed therein are passed through the external magnetic flux. 26 can be shielded, and the noise current flowing in the AC power supply line can be suppressed.

[Modification of the present invention]
In the above embodiment, a single-phase common mode choke coil is taken as an example. However, the present invention is not limited to this, and an appropriate common mode choke coil corresponding to the number of AC phases and the number of windings to be used is included.

  In the above embodiment, copper is taken as an example of the material of the conductor. However, other than copper, a nonmagnetic conductive material such as a copper alloy or aluminum may be used.

  Further, instead of the resin case 20 in the first embodiment shown in FIGS. 1 and 2, an insulating tape may be used.

  The present invention includes appropriate modifications without impairing the object and advantages thereof, and is not limited by the numerical values shown in the above embodiments.

10: Common mode choke coil 10a: Coil assembly 12: Pedestal 14: Terminal 16: Core resin case 18a, 18b: Winding 20, 32 : Resin case 22: Copper foil tape 24: Joint portion 26: Magnetic flux direction

Claims (4)

In a common mode choke coil in which a pair of windings arranged symmetrically so that magnetic fluxes cancel each other out with respect to a normal mode current are wound on a resin case covering the toroidal core,
A conductor is arranged in a loop around the toroidal core around which the pair of windings are wound ,
The conductor has an axis of the conductor perpendicular to the axis of the toroidal core, and the conductor has an axis of symmetry of the pair of windings orthogonal to the axis of the toroidal core. The axial center line is arranged so as to be substantially parallel, and the winding is shielded by flowing an induced current through the conductor loop by an external magnetic field from the same direction as the axis of the conductor loop. A common mode choke coil.
2. The common mode choke coil according to claim 1, wherein the conductor is made of a nonferromagnetic metal.
2. The common mode choke coil according to claim 1, wherein the conductor is a copper foil tape, and is attached to the outside of an insulator including an insulating tape disposed so as to surround the toroidal core. Is a common mode choke coil characterized by being electrically joined.
The common mode choke coil according to claim 1, wherein the conductor is a copper plate or a copper foil, and is disposed outside a rectangular resin case disposed around the toroidal core. Common mode choke coil.

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