JP2012109351A - Coil component and power supply circuit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil component having a novel structure capable of reducing loss.SOLUTION: The coil component 10 comprises a magnetic core 100, a magnet member 200 for applying a magnetic bias, an insulating isolation member 300, two coils 410 and 420, a holding member, and a metal case 600. The magnetic core 100 includes a corrugating medium 102 having a gap 130, and forms a closed magnetic path. A magnet member 200 is provided in the gap 130. The coils 410 and 420 are arranged with a space between one another in a Z direction so as not to cover the center of the gap 130 in the Z direction in a plane parallel with an XY plane. With such an arrangement, generation of an eddy current on the coils 410 and 420 due to magnetic flux that leaked from the gap 130 can be reduced.

Description

  The present invention relates to a coil component having a gap in the middle core constituting a part of a closed magnetic circuit and a power supply circuit using the same.

  Examples of the coil component in which the magnetic biasing means such as a magnet is provided in the closed magnetic circuit include those disclosed in Patent Document 1 and Patent Document 2.

  In the coil component of Patent Document 1, a gap is formed in the outer peripheral portion of the magnetic core, and a ring-shaped magnet is provided in the gap. If a magnet is incorporated in the gap at the outer periphery of the magnetic core as in the coil component of Patent Document 1, the volume of the magnet must be increased. However, when the volume of the magnet is increased, it becomes difficult to manufacture the entire coil component at a low cost, and there is a risk that the amount of heat generated in the magnet increases during use.

  On the other hand, in the coil component of Patent Document 2, a gap is provided in the core of the magnetic core, and a magnet is disposed at a portion including the gap. In the case of the coil component of Patent Document 2, the size of the magnet can be reduced as compared with the case of Patent Document 1, and therefore, it is predicted that the problems in Patent Document 1 can be solved.

JP 2005-159027 A JP-A-7-176431

  As a general demand, coil parts are required to further reduce loss. This request is independent of the presence or absence of a reverse bias magnet.

  Therefore, an object of the present invention is to provide a coil component having a new structure capable of further reducing loss.

  The inventor of the present application finds that eddy current loss occurs on the coil surface when leakage magnetic flux from the gap passes through the coil, and suppresses generation of eddy current loss on the coil due to leakage magnetic flux from the gap. Accordingly, the coil is divided into two or more parts (coil parts), and the coil parts are arranged so as not to cover at least the center of the gap, preferably the entire gap. Specifically, the inventor of the present invention provides the following solutions.

That is, the present invention provides the first coil component as
A coil component comprising a magnetic core including a core having a gap and forming a closed magnetic circuit, and two coil parts connected to or connected to each other,
The center core extends in a predetermined direction and is inserted into the two coil portions,
Each of the coil portions provides a coil component that is spaced apart from each other in the predetermined direction so as not to cover the center of the gap in the predetermined direction.

Further, the present invention is a first coil component as the second coil component,
Each of the coil portions provides a coil component arranged so as not to cover the gap.

The present invention is the first or second coil component as the third coil component,
A coil component further provided with a magnet member magnetized along the predetermined direction and provided in the gap is provided.

Moreover, this invention is a 3rd coil component as a 4th coil component,
The magnet member provides a coil component comprising a block obtained by injection molding a mixture of heat-resistant plastic and magnet powder.

Further, the present invention is any one of the first to fourth coil components as the fifth coil component,
The coil unit provides coil components that are connected in parallel or connected in parallel.

Moreover, this invention is a coil component in any one of 1st thru | or 5 as a 6th coil component,
The magnetic core is formed by opposingly arranging two E-type cores each having a central magnetic leg,
The central core is constituted by the central magnetic legs of the two E-type cores,
The gap provides a coil component provided between the central magnetic legs.

Moreover, this invention is a 6th coil component as a 7th coil component,
The two coil portions provide coil components respectively disposed around the central magnetic legs of the two E-shaped cores.

Further, the present invention is any one of the first to fifth coil components as the eighth coil component,
The magnetic core is configured by combining two pod cores each having a central magnetic leg,
The core is composed of the central magnetic legs of the two pod cores,
The gap provides a coil component provided between the central magnetic legs.

Further, the present invention is any one of the first to eighth coil components as the ninth coil component,
A coil component further comprising a holding member that aligns and holds the end portions of the two coil portions is provided.

Further, the present invention is any one of the first to ninth coil components as the tenth coil component,
A coil component further comprising a metal case for accommodating the two coil portions and the magnetic core is provided.

Further, the present invention is any one of the first to tenth coil components as the eleventh coil component,
There is provided a coil component further comprising an isolation member made of an insulator enclosing the core and for securing a distance between the core and the coil portion.

  Furthermore, the present invention provides a power supply circuit including any one of the first to eleventh coil components as the twelfth coil component.

  The coil is divided into two or more parts (coil parts), provided apart from each other, and the center of the gap is provided between the coil parts, so that the insulating coating layer of the coil is removed by the magnetic flux leaking from the gap. The occurrence of eddy current loss in the conductor can be suppressed.

  In addition, in the case where a magnet member is provided in the gap, the number of magnetic fluxes that pass through the magnet member out of the magnetic flux generated by passing current through the coil can be reduced, so that eddy current loss occurs on the magnet member. Therefore, it is possible to use a material having a relatively high conductivity as the magnet member.

  Furthermore, in the case of the coil component of Patent Document 2, there is a problem that the reverse bias effect is difficult to stabilize due to variations in the shape of the magnet due to the magnet manufacturing method. A stable reverse bias effect can be obtained.

It is a figure which shows the power supply circuit by the 1st Embodiment of this invention. It is a perspective view which shows the coil components by the 1st Embodiment of this invention. It is sectional drawing which shows the coil components of FIG. 2 along the III-III line. It is a graph which shows the relationship (DC current superimposition characteristic) of a direct current and an inductance. It is a graph which shows the relationship between an effective value electric current and an inductance. It is a disassembled perspective view which shows the coil components by the 2nd Embodiment of this invention. It is sectional drawing which shows the coil components of FIG.

(First embodiment)
Referring to FIG. 1, a power supply circuit 1 according to a first embodiment of the present invention is of a current control type, and includes a converter 2 incorporating a coil component 10, a switching element 3, and a control circuit for controlling the switching element 3. 4 is used by being connected to a load 5 such as a motor. In the power supply circuit 1, the coil component 10 is used to store energy as magnetic energy E = (1/2) × L × (I ² ) to smooth current and change voltage.

  As shown in FIGS. 2 and 3, the coil component 10 according to the present embodiment includes a magnetic core 100, a magnet member 200 for applying a magnetic bias, an insulating isolation member 300, and two coil portions 410. 420, a holding member 500, and a metal case 600.

  As shown in FIG. 3, the magnetic core 100 includes a core 102 having a gap 130 and forms a closed magnetic circuit. In particular, the magnetic core 100 according to the present embodiment forms a closed magnetic circuit such that the digital number 8 is placed on the YZ cross section passing through the center core 102.

  Specifically, the magnetic core 100 is formed by arranging two E-type cores 110 and 120 to face each other. The core 102 of the magnetic core 100 is composed of a central magnetic leg 112 of the E-type core 110 and a central magnetic leg 122 of the E-type core 120. The core 102 according to the present embodiment, that is, the center magnetic legs 112 and 122 extend along the Z direction (predetermined direction). The central magnetic leg 112 and the central magnetic leg 122 are provided to be separated from each other in the Z direction, and the gap 130 is located between the central magnetic legs 112 and 122. The magnetic core 100 according to the present embodiment is formed of a material having a relatively high saturation magnetic flux such as MnZn ferrite, for example.

  As shown in FIG. 3, the magnet member 200 is provided in the gap 130. The magnet member 200 is magnetized along the Z direction, and continues to supply a static magnetic field in a direction opposite to the reverse bias effect (the magnetic field generated by the effective current value flowing through the coil portions 410 and 420), that is, the reverse bias. Is arranged so that you can get). The magnet member 200 can have various shapes as long as it is interposed in the gap 130. For example, the magnet member 200 may have a larger cross-sectional area than the center core 102 in a plane parallel to the XY plane. The magnet member 200 according to the present embodiment is obtained by injection molding a mixture of heat-resistant plastic, PPS, nylon 12, heat-resistant nylon and the like and magnet powder. As the magnet powder, for example, a ferrite magnet, an NdFe-based magnet, an SmCo-based magnet powder, or the like can be used. Thus, if the magnet member 200 is configured by injection molding of a mixture of magnet powder and heat-resistant plastic, the magnet member 200 having a highly accurate shape and size can be manufactured at low cost. Therefore, a stable reverse bias effect can be obtained when it is arranged in the gap 130.

  As shown in FIG. 3, the isolation member 300 is a so-called insulating bobbin, and two coil portions 410 and 420 are provided around the cylindrical bobbin main body. Specifically, the coil portions 410 and 420 are located in the vicinity of the flanges of the insulating bobbin. The magnet member 200 is held in the bobbin main body of the separating member 300 while being sandwiched between the center magnetic legs 112 and 122. The isolation member 300, particularly the bobbin main body, is for ensuring a creepage distance between the coil portions 410 and 420 and the core 102. Insulating tape (not shown) is wound around the outer sides of the coil portions 410 and 420 in the present embodiment, whereby the outer portions of the coil portions 410 and 420 and the magnetic core 100 (the outer sides of the E-type cores 110 and 120). The creepage distance to the magnetic leg) is also secured.

  Coil portions 410 and 420 according to the present embodiment are configured by winding a circular cross-section wire formed by insulatingly covering a copper wire having a circular cross section.

  As shown in FIG. 3, the coil portion 410 and the coil portion 420 are disposed so as to surround the core 102 in a plane parallel to the XY plane and to be separated from each other in the Z direction. Specifically, the coil part 410 and the coil part 420 are respectively arranged around the central magnetic leg 112 of the E-type core 110 and the central magnetic leg 122 of the E-type core 120 constituting the magnetic core 100. Moreover, the coil part 410 and the coil part 420 are spaced apart from each other in the Z direction so as not to cover the center of the gap 130 in the Z direction in a plane parallel to the XY plane. That is, the coil part 410 and the coil part 420 do not exist in a plane that passes through the center of the gap 130 in the Z direction and is parallel to the XY plane. With this arrangement, it is possible to reduce the occurrence of eddy currents in the conductor except the coil portion 410 and the insulating coating layer of the coil portion 420 due to the magnetic flux leaking from the gap 130.

  In particular, the coil portions 410 and 420 according to the present embodiment are arranged apart from each other in the Z direction so as not to cover the gap 130 in a plane parallel to the XY plane. That is, the gap 130 is located between the coil parts 410 and 420 in the Z direction, and the coil part 410 and the coil part 420 are present in a plane including the gap 130 and parallel to the XY plane. Absent. By arranging in this way, the above-described effect of reducing eddy current loss can be further enhanced.

  The holding member 500 shown in FIG. 2 is for aligning and holding the end portion 412 of the coil portion 410 and the end portion 422 of the coil portion 420. Since the end portions 412 and 422 of the coil portions 410 and 420 are aligned and held by the holding member 500, the end portions of the coil portions 410 and 420 are mounted when the coil component 10 is mounted on a circuit board (not shown). 412 and 422 can be appropriately connected to a circuit pattern on a circuit board (not shown).

  In particular, in the present embodiment, the coil part 410 and the coil part 420 are connected in parallel on the holding member 500. However, the present invention is not limited to this, and the coil part 410 and the coil part 420 may be connected in parallel on a circuit board (not shown) on which the coil component 10 is mounted. Moreover, the coil part 410 and the coil part 420 may be connected in series depending on a use, when satisfy | filling the relationship with the gap 130. FIG.

  As understood from FIGS. 2 and 3, the metal case 600 accommodates the components such as the magnetic core 100 described above in consideration of the influence of vibration shock when the coil component 10 is mounted on a vehicle or the like. Is for. When this influence is not taken into consideration, the metal case 600 may not be used. The metal case 600 is provided with a fixing portion 610 for fixing the coil component 10 to a circuit board (not shown). The coil component 10 can be fixed to the circuit board (not shown) by inserting the fixing portion 610 into the circuit board (not shown).

In order to confirm the principle and effect of the coil component 10 according to the embodiment of the present invention, various coil components were prototyped and tested. The magnetic core 100 was formed by cutting the central magnetic leg of an FEER type core (FEER42-BH1, MnZn ferrite EE core) manufactured by NEC TOKIN Corporation by 1.75 + 0.4 mm. The gap 130 of the magnetic core 100 was 3.50 + 0.8 mm in the Z direction. The magnet member 200 was produced by injection molding a ferrite magnet powder dispersed in a heat resistant plastic. The magnet member 200 had a size of Φ15 × 3.5 mm. This magnet member 200 was magnetized in the Z direction by air-core coil magnetization. The result of measuring the magnitude of the magnetic flux density on the center surface of the magnetic member 200 after magnetization was 40.0 to 40.6 mmT. The separator member 300 was wound with a polyester enamel wire (PEW) having a diameter of 2.4 mm as a coil portion or a coil as described in Examples 1 to 4 below. The magnetic core 100 and the magnet member 200 were attached to the coil member or the separating member with the coil, the coil components of Examples 1 to 4 below were produced, and the DC superimposed current characteristics were measured. Note that when the coil components of Examples 1 and 2 were manufactured, the magnet member 200 was not inserted into the gap 130 of the magnetic core 100.
Example 1: Coil part is 3.5 turns x 2 pieces, no bias (no magnet member 200)
Example 2: 7 turns x 1 coil (no coil splitting, the coil covers the gap)
No bias (no magnet member 200)
Example 3: Coil part is 3.5 turns x 2 with bias (with magnet member 200)
Example 4: 7 turns x 1 coil (no coil splitting, the coil covers the gap)
With bias (with magnet member 200)
The measurement results at room temperature (25 ° C.) are shown in FIG.

  As understood from FIG. 4, the inductance values when the direct current I is 50 A are 4.72 μH in Example 1, 4.68 μH in Example 2, 5.10 μH in Example 3, and 4.90 μH in Example 4. there were. In other words, the configuration in which the coil does not cover the gap is superior to the configuration in which the coil is covered with the gap, and the bias is applied when the magnet member is provided in the gap and the bias is superior. Is understood.

Next, the relationship between the position of the gap and the presence or absence of bias will be described. The coil parts of Examples 5 to 10 below were produced in the same manner as described above. However, when the coil components of Examples 9 and 10 were manufactured, the external magnetic legs instead of the central magnetic legs of the E-type core were cut to form a gap in the outer core instead of the inner core of the magnetic core 100. Since gaps are formed in each outer core, when gaps are formed in the outer core, the number of gaps is two. The size of the gap was 3.5 mm regardless of whether the gap was formed on the middle core or the outer core.
Example 5: Center core gap (1 location), with bias Example 6: Center core gap (1 location), with bias Example 7: Center core gap (1 location), no bias Example 8: Center core gap (1 location), No bias Example 9: Outer core gap (2 places), with bias Example 10: Outer core gap (2 places), no bias Measurement results of coil parts of Examples 5 and 7 at 25 ° C. and Examples 6, 8 to FIG. 5 shows the measurement results of 10 coil components at 155 ° C.

  As understood from FIG. 5, the current value when the initial inductance is minus 20% is 95 A in Example 6, 59 A in Example 8, and 50 A in Example 9. In the case of Example 10, it was 45A. That is, the current value of the middle core gap was higher than that of the outer core gap, and the current value was higher with the bias than without the bias. From this, it is understood that the rated current value can be increased if a bias is applied by forming a gap in the core and inserting a magnet there.

(Second Embodiment)
Although the magnetic core 100 of the coil component 10 according to the first embodiment described above is formed by arranging the two E-type cores 110 and 120 to face each other, the present invention is not limited to this.

  As shown in FIGS. 6 and 7, the magnetic core of the coil component 10a according to the second embodiment of the present invention is a so-called pod core, which is formed by combining the upper core 110a and the lower core 120a.

  Specifically, the illustrated coil component 10a includes a magnetic core composed of an upper core 110a and a lower core 120a combined so that the central magnetic legs 112a and 122a face each other, and a magnet provided between the central magnetic legs 112a and 122a. By being accommodated in the member 200a, the separating member 310a and 320a made of an insulator that is also housed in the upper core 110a and the lower core 120a and also positions the magnet member 200a, and the separating member 310a and 320a, respectively. Coil parts 410a and 420a insulated from the upper core 110a and the lower core 120a, and holding members 500a provided with holding holes 510a and 520a for aligning and holding the end parts 412a and 422a of the coil parts 410a and 420a, Metal case 600 for housing them It is equipped with a. The coil portions 410a and 420a according to the present embodiment are configured by edgewise winding a rectangular copper wire with insulation coating, and are connected in parallel on the holding member 500a as in the first embodiment. Yes.

  Also in the case of the coil component 10a having such a structure, the coil portions 410a and 420a are provided so as not to cover the gap between the cores of the magnetic core, thereby reducing eddy current loss as occurs in the conventional configuration. can do.

  The magnetic core in the above-described embodiment is composed of two E-type cores (EE cores) arranged opposite to each other or a pod core, but the present invention is not limited to this. The magnetic core may have a shape with different division positions, such as an EI core (a combination of an E-type core and an I-type core) or a combination of an E-type core and a plate-type core.

  The coil component according to the present invention can be used for, for example, an in-vehicle power supply circuit, an inverter, and the like.

DESCRIPTION OF SYMBOLS 1 Power supply circuit 2 Converter 3 Switching element 4 Control circuit 5 Load 10,10a Coil component 100 Magnetic core 102 Middle core 110 E type core 110a Upper core 112,112a Central magnetic leg 120 E type core 120a Lower core 122,122a Central magnetism Leg 130 Gap 200, 200a Magnet member 300, 310a, 320a Isolation member 410, 410a Coil portion 412, 412a End portion 420, 420a Coil portion 422, 422a End portion 500, 500a Holding member 510a, 520a Holding hole 600 Metal case 610 Fixed Part

Claims (12)

A coil component comprising a magnetic core including a core having a gap and forming a closed magnetic circuit, and two coil parts connected to or connected to each other,
The center core extends in a predetermined direction and is inserted into the two coil portions,
Each of the coil portions is a coil component that is arranged apart from each other in the predetermined direction so as not to cover the center of the gap in the predetermined direction. The coil component according to claim 1,
Each of the coil parts is a coil component arranged so as not to cover the gap. The coil component according to claim 1 or 2,
A coil component further comprising a magnet member magnetized along the predetermined direction and provided in the gap. The coil component according to claim 3,
The magnet member is a coil component comprising a block obtained by injection molding a mixture of heat-resistant plastic and magnet powder. The coil component according to any one of claims 1 to 4,
The coil part is a coil component that is connected in parallel or connected in parallel. The coil component according to any one of claims 1 to 5,
The magnetic core is formed by opposingly arranging two E-type cores each having a central magnetic leg,
The central core is constituted by the central magnetic legs of the two E-type cores,
The gap is a coil component provided between the central magnetic legs. The coil component according to claim 6,
Two said coil parts are coil components respectively arrange | positioned around the said center magnetic leg of two said E type | mold cores. The coil component according to any one of claims 1 to 5,
The magnetic core is configured by combining two pod cores each having a central magnetic leg,
The core is composed of the central magnetic legs of the two pod cores,
The gap is a coil component provided between the central magnetic legs. The coil component according to any one of claims 1 to 8,
The coil component further comprising a holding member that aligns and holds the end portions of the two coil portions. The coil component according to any one of claims 1 to 9,
A coil component further comprising a metal case for accommodating the two coil portions and the magnetic core. The coil component according to any one of claims 1 to 10,
A coil component further comprising an isolation member made of an insulator surrounding the core and for securing a distance between the core and the coil portion.   A power supply circuit comprising the coil component according to any one of claims 1 to 11.

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