JP2020021902A - Coil and manufacturing method thereof - Google Patents

Abstract

To increase the inductance of a coil by adjusting the core.SOLUTION: A coil 2 includes a core including a conductor 4 on which a band-shaped conductor foil is wound and a magnetic body 6 on which a band-shaped magnetic foil is wound, and the conductor 4 and the magnetic body 6 are integrated in a contact state. The magnetic body 6 includes a first portion 6-1 arranged around the conductor 4, and a second portion 6-2 arranged inside the conductor 4. The first portion 6-1 of the magnetic body 6 is disposed around the conductor 4, and is linked to the conductor 4, such that the coil 2 functions as a coil. The length L11 of the conductor 4 is longer than the length L12 of the magnetic body 6, and both ends 5-1 and 5-2 of the conductor 4 protrude from the ends of the magnetic body 6. When the length L11 of the conductor 4, the length L12 of the magnetic body 6, and the magnetic path cross-sectional area and the magnetic path length of the first portion 6-1 of the magnetic body 6 are adjusted, the characteristics of the coil 2, such as inductance and resistance can be adjusted.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a coil used in an electronic circuit and a method for manufacturing the coil.

  Coils are used in electronic circuits along with resistors and capacitors. When a current flows, the coil generates a magnetic field (Ampere's law), and generates a magnetic flux corresponding to the magnetic field. When the magnetic flux changes, a voltage is generated (Faraday's law). The function of such a coil is expressed using the inductance L. The inductance L is related to, for example, the magnetic permeability μ of the core and the shape of the core.

  The higher the magnetic permeability μ, the higher the inductance L. Since the magnetic permeability μ is a ratio (B / H) of the magnetic field strength H to the magnetic flux density B, when the value of the magnetic flux density B with respect to the magnetic field strength H increases, the magnetic permeability μ and the inductance L increase.

  In a coil including a core having a hollow cylindrical shape, the impedance increases as the inductance L increases, and the impedance is determined by the ratio of the magnetic path cross-sectional area S to the magnetic path length l of the core having the hollow cylindrical shape (hereinafter, “S / l”). The ratio is known to change (for example, Patent Document 1).

JP-A-2006-225589

  When the magnetic permeability μ is increased and the inductance L is increased, the magnetic flux density B is saturated at a small magnetic field strength H. Therefore, it is necessary to suppress the current flowing through the coil and generate a small magnetic field strength H so that the magnetic flux density B is not saturated. Also, it is difficult to adjust the magnetic permeability.

Therefore, an object of the present disclosure is to increase the inductance of the coil by adjusting the core.

  To achieve the above object, according to one aspect of the present disclosure, a coil has a core including a conductor in which a strip-shaped conductor foil is wound and a magnetic body in which a strip-shaped magnetic foil is wound, The conductor and the magnetic body are integrated in a contact state.

  In the coil, the magnetic body may be arranged outside the conductor.

  In the above-described coil, the core may include a composite portion of the conductor and the magnetic body, in which a part of the band-shaped magnetic foil is overlapped on an inner surface of the band-shaped conductor foil.

  In the above coil, the band-shaped magnetic foil may include an insulating layer.

  In the above-mentioned coil, a part of the magnetic body may be disposed between the foils of the conductor over the entirety or almost the entirety of the conductor.

  In the above coil, a diameter of a cavity formed in the conductor may be smaller than a thickness of the conductor.

  In the above coil, the magnetic body may include silicon steel, a soft magnetic crystalline material, a microcrystalline material, an amorphous metal, or an amorphous alloy.

  In the above coil, the magnetic material may include an iron-based amorphous metal or an iron-based amorphous alloy.

  In order to achieve the above object, according to another aspect of the present disclosure, a method of manufacturing a coil includes a step of winding a strip-shaped conductor foil in a length direction to obtain a conductor, and a step of continuously winding the strip-shaped conductor foil. Winding a strip-shaped magnetic foil in the length direction, and contacting the conductor to obtain an integrated magnetic body.

  In the step of obtaining the conductor, a part of the band-shaped magnetic foil may be overlapped with the band-shaped conductor foil, and the band-shaped conductor foil may be wound together with the band-shaped magnetic foil.

  In the method of manufacturing a coil, a part of the strip-shaped magnetic foil may be overlapped on an inner surface of the strip-shaped conductor foil to form a composite portion of the conductor and the magnetic body.

  The coil manufacturing method may further include a step of forming an insulating layer on the strip-shaped magnetic foil.

  In the above-described method for manufacturing a coil, the strip-shaped conductor foil may be wound together with the strip-shaped magnetic foil entirely or almost entirely.

In the step of obtaining the conductor, the strip-shaped conductor foil may be wound such that a diameter of a cavity formed in the conductor is smaller than a thickness of the conductor.

According to the present disclosure, since there is no gap or a small gap between the conductor and the magnetic body, the size of the coil can be reduced. Further, since there is no gap or the gap is small, the S / l ratio of the coil can be increased, and the inductance can be increased. Further, since the conductor and the magnetic body can be integrally manufactured, the manufacturing efficiency can be improved.

FIG. 3 is a front view, a plan view, and a partial enlarged view of a plane of an example of the coil according to the first embodiment. It is a figure for explaining the magnetic path length and magnetic path cross-sectional area of a coil. It is a figure showing an equivalent circuit of a coil. It is a figure which shows the manufacturing method of a coil. It is the front view, top view, and partial enlarged view of an example of a coil concerning a 2nd embodiment. It is a figure which shows the state of the winding initial stage of a strip-shaped conductor foil and a strip-shaped magnetic foil. It is a figure which shows the direct-current superposition characteristic of the dimension and mass of a core, and the inductance of the coil which concerns on an Example and a comparative example. It is a graph which shows a DC superposition characteristic. It is a figure showing the example of mounting of a coil. It is a figure showing an example of a coil concerning a modification.

Hereinafter, embodiments and examples will be described with reference to the drawings.

First embodiment

  A first embodiment will be described with reference to FIG. 1A is a front view of an example of a coil according to the first embodiment, FIG. 1B is a plan view of an example of the coil, and FIG. 1C is a partially enlarged view of a plane of an example of the coil. . 1C is an enlarged view of a partial IC surrounded by a broken line in FIG. 1B. The coil illustrated in FIG. 1 is an example, and the technology of the present disclosure is not limited to such a coil.

  The coil 2 has a core including a conductor 4 and a magnetic body 6. The magnetic body 6 includes a first portion 6-1 arranged around the conductor 4 and a second portion 6-2 arranged inside the conductor 4. That is, at least a part (first part 6-1) of the magnetic body 6 is arranged around the conductor 4. The first portion 6-1 of the magnetic body 6 links with the conductor 4, and the coil 2 functions as a coil. The length L11 of the conductor 4 is longer than the length L12 of the magnetic body 6, and both ends 5-1 and 5-2 of the conductor 4 protrude from the ends of the magnetic body 6. When a current flows through both ends 5-1 and 5-2 of the conductor 4, the coil 2 generates a magnetic field, and a magnetic flux is generated corresponding to the magnetic field. A voltage is generated by the change in the magnetic flux. However, when the AC voltage is applied to the conductor 4, the flow of the AC current is suppressed in accordance with the frequency of the AC current due to the fluctuation of the magnetic flux. The coil 2 suppresses the flow of the high-frequency current more than the flow of the low-frequency current. The conductor 4 penetrates through the magnetic body 6, and the coil 2 forms a coil having a one-turn structure, for example. The coil 2 has, for example, a maximum current value of several tens of amperes and an inductance of several microhenries, and is suitable for a circuit of a high current system such as a drive system, a brake system, a steering system, an oil system, and a water pump system of an automobile. .

  The first portion 6-1 of the magnetic body 6 and the conductor 4 have, for example, a hollow cylindrical shape, and the coil 2 has a hollow cylindrical shape or a substantially hollow cylindrical shape as a whole. In a plan view, the coil 2 has a circular shape or a substantially circular shape.

  When the length L11 of the conductor 4, the length L12 of the magnetic body 6, the magnetic path cross-sectional area S (FIG. 2) and the magnetic path length l (FIG. 2) of the first portion 6-1 of the magnetic body 6 are adjusted, the coil 2 , Such as inductance and resistance, can be adjusted. The coil 2 has a high characteristic adjusting function.

  The conductor 4 is arranged at the center of the coil 2 in a plan view. The conductor 4 is a conductive foil and includes a conductive material such as a copper foil or an aluminum foil. The conductor 4 is made, for example, by winding a strip-shaped conductor foil 14 (A in FIG. 4) in the length direction of the strip, and the conductor 4 has a structure in which foils are laminated. The foil of the conductor 4 (hereinafter, referred to as “conductor foil portion”) is the portion of the conductor 4.

  A hollow portion 7 is formed inside the conductor 4. The cavity 7 is, for example, circular or substantially circular, and the diameter HD of the cavity 7 is smaller than the thickness T1 of the conductor 4, for example. When the diameter HD of the cavity 7 is reduced, the diameter D11 of the conductor 4 and the diameter D12 of the coil 2 are reduced, and the size of the coil 2 is reduced. When the cavity 7 is substantially circular, the diameter HD of the cavity 7 is, for example, the minimum diameter of the cavity 7.

  In the outer peripheral portion 8 of the conductor 4, a part (the second portion 6-2) of the magnetic body 6 is arranged between the conductor foil portions, and the conductor 4 is connected to the magnetic body 6. Therefore, the conductor 4 and the magnetic body 6 are integrated in contact with each other, and form a core of the coil 2. The second portion 6-2 of the magnetic body 6 is overlaid on the inner surface of the conductor foil of the conductor 4, and the second portion 6-2 of the magnetic body 6 and the conductor foil form a composite portion of the conductor and the magnetic body. I have. The connection between the conductor 4 and the magnetic body 6 suppresses a gap between the conductor 4 and the first portion 6-1 of the magnetic body 6, and the size of the coil 2 is reduced. Further, as the gap between the conductor 4 and the magnetic body 6 is suppressed, the arrangement position of the first portion 6-1 of the magnetic body 6 becomes closer to the central part of the coil 2. When the arrangement position of the first portion 6-1 approaches the central portion of the coil 2, the number of stacked magnetic foil portions of the first portion 6-1 increases, and the magnetic path cross-sectional area S increases. Further, the inner diameter and the outer diameter of the first portion 6-1 are reduced, and the magnetic path length l of the first portion 6-1 is reduced. Therefore, the S / l ratio can be increased, and the impedance and inductance can be increased. In the coil 2, the inner surface of the first portion 6-1 of the magnetic body 6 entirely contacts the outer surface of the conductor 4.

  The magnetic body 6 is a foil having magnetism, and includes a magnetic material such as silicon steel, a soft magnetic crystalline material, a microcrystalline material, an amorphous metal or an amorphous alloy. The magnetic body 6 includes a magnetic material such as an iron-based amorphous material, a cobalt-based amorphous material, an iron-based nanocrystal material, an iron-nickel-based alloy, and an iron-silicon alloy.

  An iron-based amorphous material is an example of an iron-based amorphous metal or an iron-based amorphous alloy, and is a material that is hardly magnetically saturated. Since the coil 2 including the iron-based amorphous material has an inductance even when a current is superimposed, the coil 2 can have an inductance while outputting a current. The maximum current of the coil 2 including the iron-based amorphous material is, for example, 100 to 200 amperes, the frequency of the coil 2 is, for example, 0 to 100 MHz, and the coil 2 is suitable for, for example, a line filter or a normal mode choke coil. I have.

  The thickness of the magnetic foil including the iron-based amorphous material is, for example, 20 μm or about 20 μm, which is thin. Therefore, the magnetic foil including the iron-based amorphous material may be formed by winding the magnetic foil alone, or by using the magnetic foil and the conductor foil. It is suitable for winding a laminated foil having. The magnetic permeability of the magnetic foil containing the iron-based amorphous material can be controlled by heat treatment in a wide range of, for example, 150 to 5000 [H / m]. Magnetic foils containing iron-based amorphous materials have excellent availability and cost performance.

  The cobalt-based amorphous material is an example of an amorphous metal or an amorphous alloy, and has a square BH curve (magnetic hysteresis curve) at high frequencies. The maximum current of the coil 2 containing a cobalt-based amorphous material is, for example, 100 to 200 amperes, and the coil 2 is suitable for, for example, a saturable coil and is suitable for suppressing spike noise generated at the time of switching of a semiconductor element. Further, the coil 2 including a cobalt-based amorphous material has a high impedance in a wide frequency range, for example, 0.01 to 30 MHz, and the coil 2 is suitable for, for example, a line filter or a normal mode choke coil.

  A magnetic foil containing a cobalt-based amorphous material is suitable for winding only a magnetic foil or winding a laminated foil. With a magnetic foil containing a cobalt-based amorphous material, a square BH curve is easily obtained by heat treatment, and a flat BH curve is easily obtained by magnetic field heat treatment in a direction perpendicular to the magnetic path. That is, the magnetic foil containing the cobalt-based amorphous material has a high ability to adjust the BH curve.

  An iron-based nanocrystal material is an example of a microcrystalline material, has a square BH curve at high frequencies, has a high saturation magnetic flux density, and can absorb high-energy pulses. The maximum current of the coil 2 including the iron-based nanocrystal material is, for example, 100 to 200 amperes. The coil 2 is suitable for, for example, a saturable coil and is suitable for suppressing spike noise generated at the time of switching of a semiconductor element. Further, the coil 2 including the iron-based nanocrystal material has a high impedance at a wide frequency, for example, 0.01 to 30 MHz, and the coil 2 is suitable for, for example, a line filter or a normal mode choke coil.

  A magnetic foil containing an iron-based nanocrystal material is suitable for winding only a magnetic foil or winding a laminated foil. In a magnetic foil containing an iron-based nanocrystal material, a square BH curve is easily obtained by magnetic field heat treatment, and a flat BH curve is easily obtained by magnetic field heat treatment in a direction perpendicular to the magnetic path. That is, the magnetic foil containing the iron-based nanocrystal material has a high ability to adjust the BH curve. Magnetic foils containing iron-based nanocrystal materials have good availability and cost performance.

  An iron-nickel alloy is an example of a soft magnetic crystal material, has a square BH curve, has a high saturation magnetic flux density, and can absorb high-energy pulses. The maximum current of the coil 2 containing an iron-nickel alloy is, for example, 100 to 200 amperes. The coil 2 is suitable for, for example, a saturable coil and is suitable for suppressing spike noise generated at the time of switching of a semiconductor element. The coil 2 containing an iron-nickel alloy has a high impedance, for example, a frequency of 0.1 to 1 MHz, and the coil 2 is suitable for, for example, a line filter or a normal mode choke coil.

  In a magnetic foil containing an iron-nickel alloy, a square BH curve is easily obtained by magnetic field heat treatment, and a flat BH curve is easily obtained by magnetic field heat treatment in a direction perpendicular to the magnetic path. That is, the magnetic foil containing the iron-nickel alloy has a high ability to adjust the BH curve.

  Iron-silicon alloys are an example of silicon steel, and magnetic foils containing iron-silicon alloys are widely distributed in the market and have excellent availability and cost performance. The coil 2 comprising an iron-silicon alloy is suitable for a line filter or a normal mode choke coil, for example, at low frequencies.

The magnetic material 6 has an insulating layer on the inner surface or outer surface of the foil, and the magnetic material is exposed on the other surface of the foil of the magnetic material 6. The insulating layer insulates between the laminated foils of the magnetic body 6 in the laminating direction. The insulating layer divides the eddy current generated by the noise current into each layer of the magnetic body 6 and efficiently converts the noise into heat. The insulating layer has an insulating property and is, for example, an aggregate of non-magnetic insulating powder. The insulating layer is, for example,
(1) natural inorganic compounds such as sodium silicate, alkali aluminosilicate, alkali phyllosilicate, silicon carbide, calcium sulfate hemihydrate, potassium carbonate, magnesium carbonate, calcium carbonate, barium sulfate;
(2) metal oxides such as aluminum oxide, boron oxide, magnesium oxide, silicon dioxide, tin dioxide, zinc oxide, zirconium dioxide, diantimony pentoxide, titanium oxide,
(3) Ceramics composed of multiple oxides such as perovskite, silicate glass, phosphate, titanate, niobium, tantalum, tungstate, aluminum nitride, sintered aluminum oxynitride, boron nitride, magnesium boron nitride , Boron nitride composites, nitrides such as silicon nitride, silicon nitride lanthanum, sialon, carbides such as boron carbide, silicon carbide, boron aluminum carbide, titanium carbide, titanium diboride, calcium hexaboride, lanthanum hexaboride, etc. Ceramics formed by a single or composite ceramic material exemplified by boride of
It is. The insulating layer may be a single material or a mixture of a plurality of materials. The insulating layer is preferably an aggregate of powders of, for example, silicon dioxide, aluminum oxide, zirconium dioxide, diantimony pentoxide, or titanium oxide. The insulating layer may have an air layer between the insulating powders. The air layer has insulating properties and can increase the insulating properties of the insulating layer.

  The magnetic body 6 is formed, for example, by winding a band-shaped magnetic foil 20 (C in FIG. 4) in the length direction of the band, and the magnetic body 6 has a structure in which foils are laminated. The foil of the magnetic material 6 (hereinafter, referred to as “magnetic foil portion”) is the portion of the magnetic material 6. Since the magnetic body 6 has an insulating layer on one surface, the magnetic foil portion is insulated in the laminating direction of the magnetic foil portion. The magnetic body 6 is electrically connected to the conductor 4 on another surface. Since the winding of the conductor 4 around the magnetic body 6 is one turn, that is, less than one turn, the conductor 4 itself does not short-circuit. Therefore, the conductor 4 may not be insulated and may be electrically connected to the magnetic body 6. In the outer peripheral portion 8 of the conductor 4, the conductor 4 is insulated by the magnetic material 6 in the laminating direction of the conductor foil portion.

  At the outer peripheral end 10 of the magnetic body 6, the laminated magnetic foil portions are connected by a fixing member 12 such as spot welding or other welding. The fixing member 12 prevents the shape of the magnetic body 6 from returning to its original shape such as a band shape due to springback.

  FIG. 3 shows an equivalent circuit of the coil 2. The conductor 4 having the electric resistance R1 is connected in parallel to the magnetic body 6 having the electric resistance R2. Since the first portion 6-1 of the magnetic body 6 links to the conductor 4, the coil 2 includes the inductor L. The inductor L is connected in series to the electric resistance R1 and the electric resistance R2. Since the electric resistance R1 of the conductor 4 is sufficiently smaller than the electric resistance R2 of the magnetic body 6, the current mainly flows through the conductor 4. Since the electric resistance R1 is connected in parallel with the electric resistance R2, the electric resistance of the coil 2 becomes smaller than the electric resistance R1. That is, in the coil 2, the other surface of the magnetic body 6 is electrically connected to the conductor 4, so that the electric resistance of the coil 2 is reduced, and the current loss due to the electric resistance is suppressed. Further, since the coil 2 has the inductor L, the coil 2 can suppress high-frequency current such as noise.

When a DC current or an AC current on which a high-frequency current such as noise is superimposed is input to the coil 2, the high-frequency current is attenuated by being converted into heat energy by the inductor L. DC or AC current flows through the inductor L and the electrical resistances R1, R2. Since the combined resistance of the electric resistances R1 and R2 is small, the loss of DC current or AC current is small. Since coil 2 has conductor 4, a current of, for example, 100 to 200 amperes can flow.

〔Production method〕

  FIG. 4 shows a method of manufacturing the coil. 4A, 4B, 4C, and 4D show the coil being manufactured from a planar direction.

  As shown in FIG. 4A, one end of the strip-shaped conductor foil 14 is arranged in the slit 18 of the winding shaft 16. The winding shaft 16 is an example of a foil winding device for winding a foil, and the diameter of the winding shaft 16 is set to be smaller than the thickness T1 of the conductor 4, for example. The winding shaft 16 is rotated counterclockwise, for example, and a part of the strip-shaped conductor foil 14 is wound around the winding shaft 16 to obtain the conductor 4 as shown in FIG. Before the entire strip-shaped conductor foil 14 is wound, one end of the strip-shaped magnetic foil 20 is disposed between the conductor 4 and the strip-shaped conductor foil 14, as shown in FIG. 4C. The winding shaft 16 is rotated, and the remaining strip-shaped conductor foil 14 is wound together with the strip-shaped magnetic foil 20. After the entire strip-shaped conductor foil 14 is wound, the remaining strip-shaped magnetic foil 20 is continuously wound around the conductor 4 by the rotation of the winding shaft 16, and as shown in FIG. Get 6.

After the winding shaft 16 is removed from the conductor 4, the conductor 4 and the magnetic body 6 are annealed by heat treatment, and the outer peripheral end 10 of the magnetic body 6 is welded, for example, to obtain the coil 2.

[Effects of the First Embodiment]

  (1) Since there is no gap or a small gap between the conductor and the magnetic body, the size of the coil can be reduced. Further, since there is no gap or the gap is small, the innermost circumference of the magnetic body can be set closer to the center of the coil. By starting to wind the band-shaped magnetic foil from the central portion having a small circumference, the number of windings of the band-shaped magnetic foil is increased, and the circumference of the inner surface of the magnetic body is reduced. Since the number of windings of the magnetic foil increases, the magnetic material has a large sectional area (magnetic path sectional area S). In addition, since the circumference of the inner surface of the magnetic body is small, the magnetic path length l can be reduced. Therefore, the S / l ratio of the coil can be increased, and the inductance of the coil can be increased.

  (2) As the frequency of the current increases, the current concentrates on the surface of the conductive material due to the skin effect. However, since the conductor 4 of the coil 2 has the laminated conductor foil portion, the conductor 4 is easily divided in the lamination direction of the foil, and the current is easily dispersed. When the magnetic foil portion is disposed between the conductor foil portions, the conductor foil portion is easily separated by the insulating layer of the magnetic body 6. The division of the conductor 4 can be increased by increasing the number of magnetic foil portions arranged between the conductor foil portions. By dispersing the current, the skin effect is reduced, and a large current can flow through the coil 2.

  (3) Since the second portion 6-2 of the magnetic body 6 is arranged in the conductor 4, the arrangement area of the conductor 4 is increased by the second portion 6-2. The area occupied by the second portion 6-2 may be large or small. The heat radiation effect of the coil 2 is improved in accordance with the enlargement of the area where the conductors 4 are arranged, and the temperature of the coil 2 during use can be reduced.

  (4) Since one end of the strip-shaped magnetic foil 20 is disposed between the conductor 4 and the strip-shaped conductor foil 14, the conductor 4 and the magnetic body 6 can be formed continuously and integrally. Therefore, the manufacturing burden of the coil 2 is small.

  (5) When a magnetic body having a hollow cylindrical shape is obtained by winding a magnetic foil attached to a winding shaft, an end of the magnetic foil may remain in the hollow of the magnetic body. When a linear conductor is inserted into this magnetic body to obtain a coil, the end of the magnetic foil inside the hollow may hinder insertion of the conductor, and the production efficiency may be reduced. However, the conductor 4 and the magnetic body 6 can be formed continuously and integrally, and such an inconvenience of insertion can be avoided.

  (6) Conductive foil has more flexibility than, for example, magnetic foil. Therefore, by winding at least one end of the band-shaped magnetic foil 20 together with the band-shaped conductor foil 14, the band-shaped magnetic foil 20 is easier to wind than when only the band-shaped magnetic foil 20 is wound. When winding only a magnetic foil having a higher hardness than the conductor foil, the inner diameter of the magnetic body 6 is relatively large. However, at least one end of the band-shaped magnetic foil 20 is wound together with the band-shaped conductor foil 14, so that the starting portion of the band-shaped magnetic foil 20 is protected and reinforced by the conductor foil. Even when the winding start portion has a large curvature, the winding start portion is hardly broken due to protection and reinforcement by the conductor foil. The inner diameter (diameter D11) of the first portion 6-1 and the inner diameter of the second portion 6-2 of the magnetic body 6 can be reduced, and the inductance of the coil 2 can be increased.

  (7) Characteristics such as inductance and electric resistance of the coil 2 can be adjusted by adjusting the width, thickness or length of one or both of the strip-shaped conductor foil 14 and the strip-shaped magnetic foil 20. The characteristics of the coil 2 can be adjusted by the magnetic path cross-sectional area S and the magnetic path length 1 of the first portion 6-1 of the magnetic body 6. Further, the characteristics of the coil 2 can be adjusted by the amount of the magnetic foil portion arranged between the conductor foil portions. Adjustment of the characteristics of the coil 2 is easy.

  (8) The strip-shaped conductor foil 14 and the strip-shaped magnetic foil 20 are wound in the longitudinal direction of the strip, and the current flows in the width direction of the conductor foil and the magnetic foil. it can. Therefore, a larger current can flow in the coil 2 than when a current flows in the longitudinal direction of the band.

(9) Since the magnetic material 6 is used as the core, the coil 2 has higher responsiveness than, for example, ferrite beads, and has, for example, high absorption for pulse noise.

Second embodiment

  A second embodiment will be described with reference to FIG. FIG. 5A is a front view of an example of the coil according to the second embodiment, FIG. 5B is a plan view, and FIG. 5C is a partial enlarged view of a plane. 5C is an enlarged view of a portion VC surrounded by a broken line in FIG. 5B. The coil illustrated in FIG. 5 is an example, and the technology of the present disclosure is not limited to such a coil. 5, the same parts as those in FIG. 1 are denoted by the same reference numerals.

  In the coil 2 according to the first embodiment, a part (the second part 6-2) of the magnetic body 6 is disposed between the conductor foil parts on the outer peripheral part 8 of the conductor 4. In the coil 32 according to the second embodiment, a part (the second part 6-2) of the magnetic body 6 is disposed between the conductor foil parts of the conductor 4 entirely or almost entirely. That is, in the central portion of the coil 32, the conductor foil and the magnetic foil which are superimposed on each other are wound to form the conductor 4 and the second portion 6-2 of the magnetic body 6. The conductor 4 and the second part 6-2 of the magnetic body 6 form the conductor part 34 of the coil 32, and the remaining part (first part 6-1) of the magnetic body 6 is arranged around the conductor 4. ing. Since the first portion 6-1 of the magnetic body 6 arranged around the conductor 4 links to the conductor 4, the coil 32 functions as a coil.

  The length L21 of the conductor 4 of the conductor portion 34 is longer than the length L22 of the magnetic body 6, and both ends 5-1 and 5-2 of the conductor 4 protrude from the ends of the magnetic body 6. The characteristics of the coil 32 can be adjusted by adjusting the length L21 of the conductor 4, the length L22 of the magnetic body 6, the magnetic path cross-sectional area S and the magnetic path length l of the first portion 6-1 of the magnetic body 6.

  The first portion 6-1 and the conductor portion 34 of the magnetic body 6 have, for example, a hollow cylindrical shape, and the coil 32 has a hollow cylindrical shape or a substantially hollow cylindrical shape as a whole. In a plan view, the coil 32 has a circular shape or a substantially circular shape.

  The material of the conductor 4 is the same as the material of the conductor 4 of the first embodiment. The material of the magnetic body 6 is the same as the material of the magnetic body 6 of the first embodiment. Further, as in the first embodiment, the magnetic body 6 has an insulating layer on the inner surface or outer surface of the foil, and the magnetic material is exposed on other surfaces.

  In a plan view, the conductor portion 34 is arranged at the center of the coil 32. Since the conductor section 34 includes the conductor 4, the conductor section 34 has conductivity. In the conductor portion 34, a conductor foil portion and a magnetic foil portion are alternately laminated. As a result, the thickness T2 of the conductor portion 34 is larger than the thickness of the conductor 4 alone. When a voltage is applied to both ends 5-1 and 5-2 of the conductor 4, the conductor 4 generates heat. In the coil 32, the conductor foil portions and the magnetic foil portions are alternately laminated, so that the current passing through the coil 32 is distributed to each conductor foil portion. As a result, the heat-generating portions of the conductor 4 are dispersed, and local heating is suppressed. In addition, since the heat generated in the conductor 4 is conducted to the magnetic foil between the conductor foils, a rise in the temperature of the conductor portion 34 is suppressed.

  The diameter HD of the cavity 7 is, for example, smaller than the thickness T2 of the conductor 34, that is, the thickness of the conductor 4 thickened by the second portion 6-2 of the magnetic body 6. When the diameter HD of the hollow portion 7 is reduced, the diameter D21 of the conductor portion 34 and the diameter D22 of the coil 32 are reduced, and the size of the coil 32 is reduced.

  Since the magnetic body 6 is arranged from the center portion to the outer peripheral portion of the coil 32, the gap between the conductor 34 and the first portion 6-1 of the magnetic body 6 is suppressed, and the coil 32 is compact. State. Further, as the gap is suppressed, the arrangement position of the first portion 6-1 of the magnetic body 6 is closer to the central portion of the coil 32. Therefore, the magnetic path length l of the first portion 6-1 of the magnetic body 6 decreases, and the magnetic path cross-sectional area S increases, so that the S / l ratio can be increased.

Other configurations are the same as in the first embodiment, and a description thereof will be omitted. The equivalent circuit of the coil 32 is the same as that of the coil 2 of the first embodiment.

〔Production method〕

In the first embodiment, one end of the strip-shaped magnetic foil 20 is disposed between the conductor 4 and the strip-shaped conductor foil 14 before the entire strip-shaped conductor foil 14 is wound. In the second embodiment, one end of the strip-shaped conductor foil 14 and one end of the strip-shaped magnetic foil 20 are arranged in the slit 18 of the winding shaft 16 as shown in FIG. The band-shaped conductor foil 14 and the band-shaped magnetic foil 20 are wound around the winding shaft 16 in a state where the winding shaft 16 is rotated counterclockwise, for example, and overlapped with each other to obtain the conductor portion 34. After that, the remaining band-shaped magnetic foil 20 is continuously wound around the conductor portion 34 by the rotation of the winding shaft 16. Other steps are the same as those in the first embodiment, for example.

[Effects of the Second Embodiment]

  (1) The same effect as in the first embodiment can be obtained. In particular, since a part of the magnetic body is arranged between the laminations of the conductors arranged on the center side of the coil, the innermost circumference of the magnetic body can be set closer to the center side of the coil. The ratio can be increased, and the inductance of the coil can be further increased.

  (2) The magnetic foil portion is arranged between the conductive foil portions, and the insulating layer of the magnetic body 6 easily separates the conductive foil portion. Since the skin effect occurs for each divided conductor foil portion, a large current can flow through the coil 32.

  (3) Since the magnetic foil portion is disposed between the conductor foil portions, heat is dispersed to the magnetic body 6 and the temperature rise of the conductor portion 34 is suppressed. Further, since the length L21 of the conductor 4 is longer than the length L22 of the magnetic body 6, a gap is formed at both ends 5-1 and 5-2 of the conductor 4, and the heat dissipation of the conductor 34 is enhanced.

  (4) Since the strip-shaped conductor foil 14 and the strip-shaped magnetic foil 20 are wound in a state of being overlapped with each other to form the conductor 4 and the magnetic body 6, the conductor 4 and the magnetic body 6 are continuously and integrally formed. Can be formed. The manufacturing burden of the coil 32 is small.

(5) Since the strip-shaped conductor foil 14 and the strip-shaped magnetic foil 20 are wound in a state of being superposed on each other, the magnetic foil having a higher hardness than the conductor foil is easily wound around the winding shaft 16 by the conductor foil, and 32 can be manufactured at high speed.

The coils of Examples 1 to 4 are manufactured by the same manufacturing method as in the second embodiment. Therefore, the coils of Examples 1 to 4 have the same configuration as the coil 32 of the second embodiment. The conductor 4 of the coil according to the first to fourth embodiments is a copper foil, and the magnetic body 6 is an iron-based amorphous material. The insulating layer of the magnetic body 6 is formed as follows.
・ Prepare an insulating powder of diantimony pentoxide. The diantimony pentoxide insulating powder has a particle size of 10 to 30 nanometers.
-Add polyvinyl alcohol to the aqueous dispersion solvent to obtain a solvent. The insulating powder is added to this solvent to obtain an insulating powder solution. In the insulating powder solution, the ratio of the insulating powder is adjusted to 20 to 30% by mass.
Apply an insulating powder solution to one surface of the band-shaped magnetic foil 20. The insulating powder solution is dried in an atmosphere at a temperature of 120 ° C. to obtain an insulating layer. In the drying of the insulating powder solution, water in the insulating powder solution evaporates.
-The thickness of the insulating layer after drying is 0.1-0.3 micrometers. In the dried insulating layer, the powders are gathered and stacked. The dried insulating layer includes at least one of the gap and the air layer.
The insulating layer after drying is heated at a temperature of 380 to 540 [° C.] for 1 to 5 hours to obtain an insulating layer. The heating at a temperature of 380 to 540 [° C.] is performed as a heat treatment for annealing after the formation of the conductor 4 and the magnetic body 6.

The coil of the comparative example is prepared as follows.
・ A core is created by winding a band-shaped iron-based amorphous material around a winding shaft.
・ Insert a copper wire into the center of the core to obtain a coil.

  The dimensions and mass of the cores of the coils of Examples 1 to 4 and Comparative Example are as shown in FIG. 7A. In the table shown in FIG. 7A, a magnetic body disposed around a conductor or an electric wire is treated as a “core” in order to make the comparison targets identical. The outer diameter, the inner diameter, and the ribbon width of the core of the coils of Examples 1 to 4 are respectively the diameter D22 of the coil 32, the diameter D21 of the conductor portion 34, and the length of the magnetic body 6 described in the second embodiment. L22.

  The outer diameters D22 of the coils of Examples 1 to 4 are 9.1 mm, 9.1 mm, 9.7 mm, and 10.1 mm, respectively, and the outer diameter (10. 2 mm) or less. Further, as shown in FIG. 7B and FIG. 8, the coils of Examples 1 to 4 have higher or substantially the same inductance as the coil of the comparative example at a current of at least 0 to 30 amperes. are doing. That is, the coils of Examples 1 to 4 can be miniaturized or have higher inductance than the coils of the comparative example. The DC superimposition characteristic is an index indicating a change in a characteristic value when a DC current is applied.

The inner diameter D21 of the core of each of the coils of Examples 1 to 4 is 1.9 mm, which is smaller than the inner diameter (3.8 mm) of the core of the coil of the comparative example. That is, the cores of the coils of Examples 1 to 4 are closer to the center of the coil than the coils of the comparative example. Such an arrangement of the cores has an effect of increasing the magnetic path cross-sectional area S and reducing the magnetic path length l. Therefore, the inductance of the coils of the first to fourth embodiments can be increased as compared with the coil of the comparative example.

Example of coil installation

  FIG. 9 shows an example of mounting a coil on a circuit. In the mounting example shown in FIG. 9, the coil 2 according to the first embodiment is mounted. However, the coil 32 according to the second embodiment may be mounted, or any one of the coils of Examples 1 to 4 may be mounted.

  In the circuit, a power supply 42 is connected to a load 44. The power supply 42 is an example of a noise generation source, and is, for example, a switching power supply. The load 44 is, for example, an electric motor of an automobile or a solenoid actuator. The coil 2 is arranged on the wiring between the power supply 42 and the load 44. The power supply 42 supplies the current to the load 44, and the coil 2 reduces the noise included in the current, and supplies the noise-suppressed current to the load 44. The noise may be removed only by the coil 2, or the noise may be removed by the coil 2 and other noise removing elements.

  In the mounting example shown in FIG. 9, the coil 2 is directly arranged in the circuit. However, the coil 2 may be housed in a protective case, or the coil 2 may be arranged in a circuit via the protective case.

  Modifications of the embodiments and examples described above are listed below.

  (1) The insulating layer may be formed on the inner surface and the outer surface of the foil of the magnetic body 6. When the insulating layers are formed on both sides, the insulating property of the magnetic body 6 is enhanced, and the eddy current generated by the noise current is easily divided into each layer of the magnetic body 6, and the noise is easily converted to heat efficiently. In the magnetic body 6, the insulating layer may be omitted. Even if the insulating layer is omitted, the first portion 6-1 of the magnetic body 6 approaches the central portion of the coil 2 or 32. Therefore, the size of the coil can be reduced, and the S / l ratio of the coil can be increased.

  (2) An insulating layer may be formed on one or both surfaces of the foil of the conductor 4 to insulate between the conductor foil portions of the conductor 4. When insulation is provided between the conductor foil portions, a skin effect is generated for each conductor foil portion, the current is dispersed, and the maximum current value of the coil can be increased.

  (3) In the first embodiment, a part of the magnetic body 6 is arranged between the conductor foil portions of the conductor 4, and the conductor 4 is connected to the magnetic body 6. However, as shown in FIG. 10, a part of the magnetic body 6 may be arranged between the conductor foil portion and the attaching member 46 attached to the conductor foil portion, and the conductor 4 may be connected to the magnetic body 6. The attaching member 46 is, for example, a conductor foil, a magnetic foil, or an insulating foil, and forms a foil of the conductor 4.

  (4) In the first embodiment, the magnetic body 6 is formed by winding one strip-shaped magnetic foil 20 in the length direction of the strip, but is wound after laminating a plurality of strip-shaped magnetic foils. May be formed. When a magnetic material is formed by winding a thick band-shaped magnetic foil, the number of windings can be reduced as compared with a case where a magnetic material having the same cross-sectional area is formed by winding a thin band-shaped magnetic foil. Therefore, when a magnetic material is formed by winding a thick band-shaped magnetic foil, productivity is improved. However, compared with a magnetic material formed using a thick band-shaped magnetic foil, a magnetic material formed using a thin band-shaped magnetic foil suppresses an eddy current that increases in a high-frequency region, so that the skin effect is reduced, and the permeability is reduced. It is possible to obtain a high impedance up to a high frequency region by suppressing a decrease in magnetic susceptibility. Therefore, a coil having a high impedance in a high-frequency region can be manufactured by improving productivity and forming a magnetic material by winding a thin band-shaped magnetic foil after laminating it. In this case, an insulating layer may be formed on at least one side of the strip-shaped magnetic foil.

  (5) Also, the embodiment in which the magnetic material is formed using one kind of magnetic material has been described, but the present invention is not limited to this, and the magnetic material may be formed using a plurality of band-shaped magnetic foils made of different magnetic materials. Good. By doing so, coils having the characteristics of the respective magnetic materials can be obtained. For example, if a magnetic body is formed using a band-shaped magnetic foil made of a magnetic material having a high magnetic permeability such as a cobalt-based amorphous material and a band-shaped magnetic foil made of a magnetic material such as an iron-based amorphous material, a large current It is possible to obtain a coil that can maintain the inductance even when any of the low currents flows. In other words, a magnetic material made of an iron-based amorphous material can secure inductance when a large current flows, and a coil made of a magnetic material made of a cobalt-based amorphous material using only an iron-based amorphous material when a low current flows. Higher inductance can be secured. A different magnetic material is formed by winding a band-shaped magnetic foil made of one magnetic material, and then forming a magnetic material around the outer periphery thereof, and then winding a band-shaped magnetic foil made of the other magnetic material. Alternatively, a magnetic body may be formed by laminating strip-shaped magnetic foils made of different magnetic materials and winding them together. In this case, an insulating layer may be formed on at least one side of the strip-shaped magnetic foil.

As described above, the most preferred embodiment of the technology of the present disclosure has been described, but the technology of the present disclosure is not limited to the above description, but is described in the claims or described in the specification. Of course, various modifications and changes can be made by those skilled in the art based on the gist of the disclosed technology of the present disclosure, and it goes without saying that such modifications and changes are included in the scope of the present disclosure.

The technology of the present disclosure can be used for removing noise of a noise source such as a switching power supply, and is useful.

2, 32 coil 4 conductor 5-1 5-2 end 6 magnetic body 6-1 first part 6-2 second part 7 cavity 8 outer peripheral part 10 outer peripheral end 12 fixing member 14 belt-shaped conductor foil 16 windings Shaft 18 Slit 20 Band-shaped magnetic foil 34 Conductor 46 Adhering part

Claims (14)

A core including a conductor in which a strip-shaped conductor foil is wound and a magnetic body in which a strip-shaped magnetic foil is wound,
The coil, wherein the conductor and the magnetic body are integrated in a contact state.
The coil according to claim 1, wherein the magnetic body is arranged outside the conductor.
3. The core according to claim 1, wherein the core has a composite portion of the conductor and the magnetic body in which a part of the band-shaped magnetic foil is overlapped on an inner surface of the band-shaped conductor foil. 4. Coil.
The coil according to claim 1, wherein the band-shaped magnetic foil includes an insulating layer.
The coil according to any one of claims 1 to 4, wherein a part of the magnetic body is disposed between or substantially all of the conductors between the foils of the conductors.
The coil according to any one of claims 1 to 5, wherein a diameter of a cavity formed in the conductor is smaller than a thickness of the conductor.
The coil according to any one of claims 1 to 6, wherein the magnetic material includes silicon steel, a soft magnetic crystalline material, a microcrystalline material, an amorphous metal, or an amorphous alloy.
The coil according to claim 7, wherein the magnetic material includes an iron-based amorphous metal or an iron-based amorphous alloy.
A step of winding a strip-shaped conductor foil in the length direction to obtain a conductor,
Continuing with the strip-shaped conductor foil, winding a strip-shaped magnetic foil in the length direction, contacting the conductor, and obtaining an integrated magnetic body,
A method for manufacturing a coil, comprising:
The method according to claim 9, wherein in the step of obtaining the conductor, a part of the band-shaped magnetic foil is overlapped with the band-shaped conductor foil, and the band-shaped conductor foil is wound together with the band-shaped magnetic foil. Manufacturing method of coil.
The method for manufacturing a coil according to claim 10, wherein a part of the strip-shaped magnetic foil is overlapped on an inner surface of the strip-shaped conductor foil to form a composite portion of the conductor and the magnetic body.
The method for manufacturing a coil according to claim 9, further comprising a step of forming an insulating layer on the strip-shaped magnetic foil.
The coil manufacturing method according to any one of claims 9 to 12, wherein the strip-shaped conductor foil is wound together or almost entirely with the strip-shaped magnetic foil.
In the step of obtaining the conductor, the strip-shaped conductor foil is wound so that a diameter of a cavity formed in the conductor is smaller than a thickness of the conductor. Item 14. The method for manufacturing a coil according to any one of items 13.

Images