KR102582072B1 - Magnetic coupling apparatus - Google Patents

Abstract

An inductor according to an embodiment of the present invention has a toroidal shape and includes a first magnetic material including ferrite and a second magnetic material disposed on the outer peripheral surface or inner peripheral surface of the first magnetic material, and the second magnetic material is located on the circumference of the first magnetic material. It includes a plurality of layers of metal ribbon and a resin material wound along a direction, wherein the resin material includes a first resin material disposed to cover the outer surface of the plurality of layers of metal ribbon and a second resin material disposed in at least a portion of the interlayer space of the plurality of layers. 2 Contains resinous substances.

Description

MAGNETIC COUPLING APPARATUS}

The present invention relates to a magnetic core, an inductor, and an EMI filter including the same.

An inductor is one of the electronic components applied to printed circuit boards, and can be applied to resonance circuits, filter circuits, power circuits, etc. due to its electromagnetic characteristics.

Meanwhile, the EMI (Electro Magnetic Interference) filter applied within the power board passes signals necessary for circuit operation and removes noise.

Figure 1 shows a block diagram of a typical power board with an EMI filter applied to a power source and a load.

The types of noise transmitted from the power board of the EMI filter shown in Figure 1 can be largely divided into radiated noise of 30 MHz to 1 GHz radiated from the power board and conducted noise of 150 kHz to 30 MHz transmitted through the power line. .

The transmission method of conducted noise can be divided into differential mode and common mode. Among these, common mode noise, even if it is a small amount, returns in a large loop, so it can affect electronic devices that are far away. This common mode noise may be caused by impedance imbalance in the wiring system, and becomes more noticeable in a high-frequency environment.

In order to remove common mode noise, the inductor applied to the EMI filter shown in FIG. 1 generally uses a toroidal magnetic core containing a Mn-Zn ferrite material. Mn-Zn-based ferrite has high permeability between 100 kHz and 1 MHz, so it can effectively remove common mode noise.

Figure 2 shows a perspective view of a general inductor 100.

Referring to FIG. 2, the inductor 100 may include a magnetic core 110 and a coil 120 wound on the magnetic core 110.

The magnetic core 110 may have a toroidal shape, and the coil 120 includes a first coil 122 wound on the magnetic core 110 and a second coil wound to face the first coil 122. It may include a coil 124. Each of the first coil 122 and the second coil 124 may be wound on the top surface (S1), the side surface (S2), and the bottom surface (S3) of the toroidal-shaped magnetic core 110.

The magnetic core 110 may further include a bobbin (not shown) to insulate the coil 120, and the coil 120 may be made of a conductor whose surface is covered with an insulating material.

Figure 3 shows an exploded perspective view when the magnetic core shown in Figure 2 further includes a bobbin, and Figures 4 (a) and 4 (b) show a process perspective view of the magnetic core shown in Figure 3.

Referring to FIG. 3, the magnetic core 110 may be accommodated in the bobbin 130. The bobbin 130 may include an upper bobbin 132 and a lower bobbin 134.

Next, referring to FIG. 4 (a), in a state where the upper bobbin 132, the magnetic core 110, and the lower bobbin 132 are provided as shown in FIG. 3, the magnetic core 110 is placed on the bottom surface of the lower bobbin 132. ) can be placed. Thereafter, the upper bobbin 131 may be coupled to the result shown in FIG. 4 (a) as shown in FIG. 4 (b). At this time, each component may be bonded to each other through an adhesive material.

In order to improve the performance of the above-described inductor, various efforts have been made, such as constructing the magnetic core 110 from different materials. For example, an Fe-Si-based metal ribbon may be disposed on at least a portion of the surface of a toroidal-shaped magnetic core containing the Mn-Zn-based ferrite material as described above. However, metal ribbons usually undergo heat treatment at high temperatures (eg, 500°C to 600°C) to obtain high magnetic properties (i.e., high magnetic permeability). However, metal ribbons that have undergone high-temperature heat treatment improve their magnetic properties, but their strength becomes too weak and they become brittle even with a small impact, making transportation and handling during the manufacturing process very difficult, which reduces workability and reduces the yield of finished products. There is a problem that causes degradation.

The technical problem to be achieved by the present invention is to provide a magnetic core component with excellent magnetic properties and strength, an inductor containing the same, and an EMI filter.

An inductor according to an embodiment has a toroidal shape and includes a first magnetic material including ferrite and a second magnetic material disposed on the outer peripheral surface or inner peripheral surface of the first magnetic material, and the second magnetic material is disposed along the circumferential direction of the first magnetic material. It includes a wound multiple-layer metal ribbon and a resin material, wherein the resin material includes a first resin material disposed to cover the outer surface of the multiple-layer metal ribbon and a second resin material disposed in at least a portion of the interlayer space of the multiple layers. Includes.

For example, the first magnetic material includes Mn-Zn-based ferrite, the second magnetic material includes a Fe-Si-based metal ribbon, and the second resin material has 0% of the total height of the second magnetic material from the bottom to the top. It can be arranged between 5% and 95% and 100%.

For example, the radial thickness of the first magnetic material may be thicker than the radial thickness of the second magnetic material, and the radial thickness of the second magnetic material may be thicker than the radial thickness of the first resin material.

For example, the thickness of the first resin material may be 20 mm to 30 mm.

For example, the height of the first resin material layer may be higher than the height of the second magnetic material.

For example, the second resin material may be disposed in an amount of 15% to 30% of the interlayer space of the plurality of layers.

For example, the second resin material may be disposed in an amount of 20% to 25% of the interlayer space of the plurality of layers.

An EMI filter according to an embodiment includes an inductor and a capacitor, the inductor has a toroidal shape, a first magnetic material including ferrite, and a second magnetic material disposed on the outer peripheral surface or inner peripheral surface of the first magnetic material, and a second magnetic material. The magnetic material may include a plurality of layers of metal ribbon and a resin material wound along the circumferential direction of the first magnetic material. Here, the resin material may include a first resin material disposed to cover the outer surface of the multiple layers of metal ribbon and a second resin material disposed in at least a portion of the interlayer space of the multiple layers.

For example, the first magnetic material includes Mn-Zn-based ferrite, the second magnetic material includes a Fe-Si-based metal ribbon, and the second resin material has 0% of the total height of the second magnetic material from the bottom to the top. It can be arranged between 5% and 95% and 100%.

For example, a portion of the second resin material may be disposed in an amount of 15% to 30% of the interlayer space of the plurality of layers.

The inductor according to the embodiment and the EMI filter including the same have improved strength and excellent magnetic properties because the magnetic core in the shape of a wound metal ribbon of multiple layers is coated with a resin material.

Figure 1 shows a block diagram of a typical power board with an EMI filter applied to a power source and a load.
Figure 2 shows a perspective view of a general inductor.
FIG. 3 shows an exploded perspective view when the magnetic core shown in FIG. 2 further includes a bobbin.
Figures 4 (a) and 4 (b) show a process perspective view of the magnetic core shown in Figure 3.
Figure 5 is a perspective view and cross-sectional view of a magnetic core according to an embodiment of the present invention.
Figure 6 is a process diagram of the magnetic core of Figure 5.
7 to 9 are perspective and cross-sectional views of a magnetic core according to another embodiment of the present invention.
Figure 10 is a graph showing the permeability and inductance of a ferrite material and a metal ribbon material.
Figure 11 is a cross-sectional image showing the epoxy ratio of the interlayer space according to the dilution ratio of the epoxy coating solution according to an embodiment.
FIG. 12 is a diagram for explaining a sample measurement area according to an embodiment, and FIG. 13 shows measurement results according to the area of FIG. 12.
Figure 14 is an example of an EMI filter including an inductor according to an embodiment.

Since the present invention can be subject to various changes and can have various embodiments, specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms containing ordinal numbers, such as second, first, etc., may be used to describe various components, but the components are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, the second component may be referred to as the first component without departing from the scope of the present invention, and similarly, the first component may also be referred to as the second component. The term and/or includes any of a plurality of related stated items or a combination of a plurality of related stated items.

When a component is said to be "connected" or "connected" to another component, it is understood that it may be directly connected to or connected to the other component, but that other components may exist in between. It should be. On the other hand, when it is mentioned that a component is “directly connected” or “directly connected” to another component, it should be understood that there are no other components in between.

In the description of the embodiments, each layer (film), region, pattern or structure is “on” or “under” the substrate, each layer (film), region, pad or pattern. The description of being formed includes all being formed directly or through another layer. The standards for top/top or bottom/bottom of each floor are explained based on the drawing. Additionally, the thickness or size of each layer (film), region, pattern, or structure in the drawings may be modified for clarity and convenience of explanation, and therefore does not entirely reflect the actual size.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Hereinafter, embodiments will be described in detail with reference to the attached drawings, but identical or corresponding components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted.

According to one embodiment of the present invention, the magnetic core may include a first magnetic material and a second magnetic material made of different materials. Here, the second magnetic material may be disposed on at least a portion of the surface of the first magnetic material and may include a wound metal ribbon of multiple layers. The second magnetic material according to this embodiment may contain a resin material to solve the problem of weakening the strength of the wound multi-layer metal ribbon after heat treatment. The resin material may include a resin material that covers the outer surface of the wound multiple-layer metal ribbon and a resin material disposed in at least a portion of the interlayer space of the multiple layers. Here, the interlayer space may mean a space formed between the outer peripheral surface of a layer relatively close to the centrifugal and the inner peripheral surface of a layer relatively far from the centrifugal direction in two ribbon layers adjacent to each other in the centrifugal direction as the metal ribbon is wound. The formation method and characteristics of the resin material will be described in more detail later, and first, various forms of different types of magnetic materials forming a magnetic core according to embodiments of the present invention will be described with reference to FIGS. 5 to 8. For convenience of explanation, illustration of the resin material is omitted in FIGS. 5 to 7.

Figure 5 is a perspective view and cross-sectional view of a magnetic core according to an embodiment of the present invention, Figure 6 is a process diagram of the magnetic core of Figure 5, and Figures 7 to 9 are a perspective view and cross-sectional view of a magnetic core according to another embodiment of the present invention. am.

Referring to FIG. 5, the magnetic core 800 includes a first magnetic material 810 and a second magnetic material 820, the first magnetic material 810 and the second magnetic material 820 are of different species, and the second magnetic material ( 820 may be disposed on at least a portion of the surface of the first magnetic material 810. At this time, the second magnetic material 820 may have a higher saturation magnetic flux density than the first magnetic material 810.

Here, the first magnetic material 810 may include ferrite, and the second magnetic material 820 may include a metal ribbon. Here, the permeability (μ) of the ferrite may be 2,000 to 15,000, and the permeability (μ) of the metal ribbon may be 100,000 to 150,000. For example, the ferrite may be Mn-Zn-based ferrite, and the metal ribbon may be an Fe-based nanocrystalline metal ribbon. The Fe-based nanocrystalline metal ribbon may be a nanocrystalline metal ribbon containing Fe and Si. The thickness of the metal ribbon may be 15 mm to 20 mm, but is not necessarily limited thereto.

At this time, the first magnetic material 810 and the second magnetic material 820 each have a toroidal shape, and the second magnetic material 820 is a second outer magnetic material 822 disposed on the outer peripheral surface (S2) of the first magnetic material 810. And it may include a second inner magnetic material 824 disposed on the inner peripheral surface (S4) of the first magnetic material 810.

At this time, the thickness of the second outer magnetic body 822 and the second inner magnetic body 824 are each thinner than the thickness of the first magnetic body 810. By adjusting at least one of the ratio between the thickness of the second outer magnetic material 822 and the thickness of the first magnetic material 810 and the ratio between the thickness of the second inner magnetic material 824 and the thickness of the first magnetic material 810, the magnetic core The permeability of (800) can be adjusted.

In order to manufacture such a magnetic core, two second magnetic materials 822 and 824 are prepared, respectively, as shown in FIG. 6. Each of the second magnetic materials 822 and 824 may be formed of a resin material formed on a metal ribbon wound in multiple layers. Among the prepared second magnetic materials 822 and 824, the second inner magnetic material 824 corresponding to the inner peripheral surface S4 of the toroidal-shaped first magnetic material 810 may be inserted into the hollow of the first magnetic material 810, The first magnetic material 810 may be inserted into the hollow of the second outer magnetic material 822 corresponding to the outer peripheral surface S2. Of course, the relative coupling order between the second magnetic materials with respect to the first magnetic material 810 may be changed.

At this time, the outer peripheral surface (S2) of the first magnetic material 810 and the second outer magnetic material 822, and the inner peripheral surface (S4) of the first magnetic material 810 and the second inner magnetic material 824 may be adhered to each other by an adhesive. At this time, the adhesive may be an adhesive containing at least one of epoxy resin, acrylic resin, silicone resin, and varnish. In this way, when dissimilar magnetic materials are joined using an adhesive, performance deterioration does not occur even during physical vibration.

Here, each of the second magnetic materials 822 and 824 may include a metal ribbon wound multiple times and stacked in multiple layers, as shown in FIG. 5 . Depending on the number of layers of the laminated metal ribbon, the thickness and permeability of the second magnetic materials 822 and 824 may vary, and the permeability of the magnetic core 800 may vary accordingly, and the EMI filter to which the magnetic core 800 is applied may vary. Noise removal performance may vary.

That is, the larger the thickness of the second magnetic materials 822 and 824, the higher the noise removal performance can be. Using this principle, metal is laminated so that the thickness of the second magnetic materials 822, 824 disposed in the area where the coil is wound is thicker than the thickness of the second magnetic materials 822, 824 disposed in the area where the coil is not wound. The number of layers of the ribbon can be adjusted.

The number of layers of the metal ribbon can be adjusted by the number of windings, the winding start point, and the winding end point. As shown in (a) of FIG. 5, the relationship between the start and end points of winding is described based on the second outer magnetic material 822 disposed on the outer peripheral surface S2 of the first magnetic material 810 as follows. Of course, as described above, the winding of the second outer magnetic material 822 and the formation of the resin material (not shown) are completed before being combined with the first magnetic material 810. However, for convenience of explanation, the first magnetic material 822 is It is assumed that winding starts based on a point on the outer surface of (810).

When winding the second outer magnetic material 822, which is a metal ribbon, when winding one turn from the winding start point, the second outer magnetic material 822 may include a one-layer metal ribbon, and can be wound two times from the winding start point. In this case, the second outer magnetic body 822 may include a two-layer metal ribbon. On the other hand, when the winding start point and the winding end point are different, for example, when winding one and a half turns from the winding start point, the second outer magnetic body 822 has an area where metal ribbons are laminated as the first layer and metal ribbons as the second layer. includes the area covered. Alternatively, when winding two and a half turns from the winding start point, the second outer magnetic body 822 includes an area where metal ribbons are stacked in two layers and an area in which metal ribbons are stacked in three layers. In this case, if the coil is placed in an area where the number of stacked layers is greater, the noise removal performance of the EMI filter to which the magnetic core 800 according to an embodiment of the present invention is applied can be further improved.

For example, when the magnetic core 800 has a toroidal shape and the first coil 122 and the second coil 124 are wound on the magnetic core 800 to be symmetrical to each other, the first magnetic material 810 The first coil 122 is disposed in an area where the number of stacked layers of the second outer magnetic material 822 disposed on the outer peripheral surface is large, and the second inner magnetic material 824 disposed on the inner peripheral surface of the first magnetic material 810 is stacked. The second coil 124 can be placed in an area with a large number of layers. Accordingly, both the first coil 122 and the second coil 124 may be disposed in an area where the number of stacked layers of the second magnetic materials 822 and 824 is large, and the first coil 122 may be placed in an area where the number of stacked layers is small. ) and the second coil 124 are not disposed, so high noise removal performance can be obtained.

The second outer magnetic body 822 and the second inner magnetic body 824 are illustrated as having the same material and thickness, but are not limited thereto. The second outer magnetic body 822 and the second inner magnetic body 824 may have different materials or different permeability, and may have different thicknesses. Accordingly, the magnetic permeability of the magnetic core 800 may have various ranges.

Meanwhile, as shown in FIG. 7, the height h1 of the first magnetic material 810 may be higher than the height h2 of the second magnetic material 820. To this end, during the manufacturing process of the second magnetic material 820, a metal ribbon whose width is shorter than the height h1 of the first magnetic material 810 may be wound. According to this, the second outer magnetic material 822 is disposed at the boundary between the upper surface (S1) and the outer peripheral surface (S2) of the first magnetic material 810 and the boundary between the lower surface (S3) and the outer peripheral surface (S2) of the first magnetic material 810. does not occur, and the second inner magnetic material 824 is disposed at the boundary between the upper surface (S1) and the inner peripheral surface (S4) of the first magnetic material 810 and the boundary between the lower surface (S3) and the inner peripheral surface (S4) of the first magnetic material 810. It may not work. Accordingly, the boundary between the upper surface (S1) and the outer peripheral surface (S2) of the first magnetic material 810, the boundary between the lower surface (S3) and the outer peripheral surface (S2) of the first magnetic material 810, the upper surface of the first magnetic material 810 ( Cracks in the second outer magnetic material 822 can be prevented at the boundary between the lower surface S1) and the inner peripheral surface S4 and the boundary between the lower surface S3 and the inner peripheral surface S4 of the first magnetic material 810.

Alternatively, as shown in FIG. 8, the second magnetic material 820 is disposed only on the outer peripheral surface (S2) of the first magnetic material 810, or as shown in FIG. 9, the second magnetic material 820 is disposed on the inner peripheral surface (S2) of the first magnetic material 810. It can also be placed only in S4).

In this way, if the magnetic core 800 includes different types of magnetic materials with different permeability, noise in a wide frequency band can be removed. In particular, compared to a toroidal-type magnetic core made only of Mn-Zn-based ferrite, the phenomenon of magnetic flux being concentrated on the surface is prevented, so the high-frequency noise removal effect is great, and the internal saturation is lowered, so it can be applied to high-power products. Additionally, by adjusting the magnetic permeability and volume ratio of the first magnetic material 810 and the second magnetic material 820, the performance of the magnetic core 800 can be adjusted.

Meanwhile, referring to FIG. 10, it can be seen that a magnetic core containing both a ferrite material and a metal ribbon material with different permeability for each frequency has a high inductance in a certain frequency range, and thus high noise removal performance can be obtained.

So far, the mutual arrangement relationship between the first magnetic material and the second magnetic material according to the embodiments has been described. Hereinafter, the resin material of the second magnetic material according to an embodiment of the present invention will be described in more detail.

According to one embodiment, the resin material may be formed by heat treating a metal ribbon wound in a plurality of layers, dipping the heat treatment result in a coating solution, and then drying it. Depending on the embodiment, the drying process may include a heat drying process in an environment of 60 degrees to 150 degrees.

As shown in (c) of FIG. 8, in the second magnetic material 820, the resin material R may be disposed on the outer surface (upper surface, lower surface, inner peripheral surface, outer peripheral surface) of the wound metal ribbon MR, It may also be placed between wound metal ribbons (not shown).

According to one embodiment, the coating solution may be a mixed solution in which an epoxy resin and a diluent are mixed at a predetermined ratio. The diluent is not limited to a specific ingredient as long as it can dissolve the epoxy resin. Tables 1 to 4 below show examples of the results of measuring the inductance reduction rate by varying the ratio of epoxy resin and diluent.

Epoxy:
diluent Sample Inductance (@16kHz) Decrease rate (%) ratio Before impregnation After impregnation 5:5 #One 65.52 45.16 -31.08 #2 60.43 42.78 -29.2 #3 59.42 41.72 -29.79 #4 65.25 46.03 -29.46 #5 64.23 47.08 -26.7 #6 55.08 41.16 -25.28 #7 62.06 41.94 -32.42 #8 64.57 43.49 -32.64 #9 63.11 43.49 -31.09 #10 72.68 50.88 -29.99 Avg. 63.23 44.37 -29.76

Epoxy:
diluent Sample Inductance (@16kHz) Decrease rate (%) ratio Before impregnation After impregnation 3:7 #One 60.96 58.96 -3.28 #2 76.36 66.32 -13.15 #3 75.26 64.16 -14.75 #4 64.41 49.25 -23.54 #5 58.02 50.02 -13.79 #6 61.46 45.99 -25.18 #7 51.35 44.05 -14.22 #8 52.56 45.64 -13.15 #9 53.93 46.08 -14.56 #10 49.89 42.64 -14.54 Avg. 60.42 51.31 -15.02

Epoxy:
diluent Sample Inductance (@16kHz) Decrease rate (%) ratio Before impregnation After impregnation 2:8 #One 60.92 53.93 -11.47 #2 55.4 53.68 -3.1 #3 49.27 44.4 -9.88 #4 45.79 48.19 5.24 #5 58.26 54.78 -5.97 #6 61.64 54.8 -11.1 #7 62.14 56.59 -8.93 #8 53.22 51.44 -3.34 #9 49.35 46.89 -4.98 #10 44.92 43.28 -3.65 Avg. 54.09 50.8 -5.72

Epoxy:
diluent Sample Inductance (@16kHz) Decrease rate (%) ratio Before impregnation After impregnation 1:9 #One 49.14 46.18 -6.02 #2 44.47 42.21 -5.09 #3 38.33 36.68 -4.3 #4 38.92 36.43 -6.39 #5 40.07 36.93 -7.85 #6 49.13 49.68 1.13 #7 57.5 55.41 -3.63 #8 44.08 42.13 -4.43 #9 41.62 41.4 -0.54 #10 44.62 40.23 -9.84 Avg. 44.79 42.73 -4.7

Referring to Tables 1 to 4, it can be seen that the higher the ratio of epoxy resin, the higher the inductance reduction rate, and the higher the diluent ratio, the lower the inductance reduction rate. Specifically, when the ratio of epoxy resin and diluent was 5:5, an inductance reduction rate of close to 30 percent was observed, and when the ratio of epoxy resin and diluent was 3:7, an inductance reduction rate of close to about 15 percent was observed. However, when the ratio of epoxy resin and diluent was 2:8 and 1:9, the inductance reduction rate was 5.72% and 4.7%, respectively, and although the difference was not large, the inductance reduction rate was relatively good.

Next, compare the strength of each diluent with reference to Table 5.

Sample Before impregnation Epoxy: thinner content ratio 5:5 3:7 2:8 1:9 #One 75 757 515 386 240 #2 56 806 494 511 297 #3 62 770 544 420 250 #4 68 774 580 583 213 #5 80 857 482 467 222 #6 61 821 543 520 236 #7 88 890 490 478 221 #8 69 874 340 478 234 #9 76 745 422 460 219 #10 63 717 499 425 174 Avg. 69.8 801.1 490.9 472.8 230.6

Table 5 shows the external force in g units that causes breakage when pressing a point on the outer peripheral surface in the radial direction after heat treatment of a metal ribbon wound in 15 layers (turns). Referring to Table 5, it can be seen that the metal ribbon before impregnation with the coating solution is broken when an external force of about 70 g is applied, but the strength is improved by about 3 to 10 times or more depending on the ratio of the epoxy resin and the diluent.

The difference in strength improvement by dilution ratio is due to the difference in viscosity of the epoxy resin depending on the dilution ratio of the coating solution (i.e., impregnation solution), which is why a larger amount of epoxy settles on the outer surface of the metal ribbon when the metal ribbon is lifted after impregnation. However, this is due to the fact that the amount of epoxy resin that penetrates into the interlayer space of the multiple layers of the metal ribbon wound in the impregnation solution also increases. In addition, the epoxy resin may expand in volume during the drying process in the interlayer space of the multiple layers of the wound metal ribbon, resulting in increased microcracks in the metal ribbon, resulting in an inductance reduction effect. This will be explained with reference to FIGS. 11 to 13. Although not shown, the position where the resin material is disposed in the interlayer space of the ribbon wound in FIGS. 11 to 13 is the total height from the bottom to the top when the total height of the second magnetic material 820 is defined as the bottom to the top. The contrast can be placed between 0% and 5% and between 95% and 100%. Preferably, it may be arranged between 0% and 15% and between 85% and 100% of the total height in the direction from the lower surface to the upper surface. More preferably, it may be arranged between 0% and 30% and between 70% and 100% of the total height in the direction from the lower surface to the upper surface. When placed between 31% and 69% of the total height from the bottom to the top, the strength improvement and inductance reduction rate may be minimal.

Figure 11 is a cross-sectional image showing the epoxy ratio of the interlayer space according to the dilution ratio of the epoxy coating solution according to an embodiment. Figure 11 shows an enlarged image of the cross-section after cutting the second magnetic material in the circumferential direction, in which a metal ribbon wound in 15 turns (turns) was impregnated with an epoxy coating solution of different dilution ratios. In addition, in FIG. 11, each image has a common bottom in a centrifugal direction, and for each dilution ratio, the top image is an image showing all 15 layers of metal ribbon, and the bottom image is an image further enlarged to show only 5 layers of metal ribbon. The circles in each bottom image indicate the area where the epoxy resin is located.

Referring to Figure 11, when the ratio of epoxy and diluent is 1:9, the epoxy resin is located in the space between adjacent ribbon layers in the centrifugal direction, that is, at a ratio of about 10% of the total interlayer space, and the ratio of epoxy to diluent is In the case of 2:8, epoxy resin is located at a ratio of about 25%. In addition, when the ratio of epoxy and diluent is 3:7, the epoxy resin is located at a ratio of about 30% of the total interlayer space, and when the ratio of epoxy and diluent is 5:5, the epoxy resin is located at a ratio of about 50%.

As shown in Figure 11, it can be seen that the strength varies depending on the proportion of epoxy resin in the interlayer space.

Below, we comprehensively compare the inductance reduction in Tables 1 to 4 and the strength improvement in Table 5.

When the ratio of epoxy to diluent was 5:5, the strength was highest, but the inductance reduction rate was too high. When the epoxy to diluent ratio was 1:9, the inductance reduction rate was lowest, but the strength improvement was low.

In addition, similar excellence was shown in terms of inductance reduction rate when the ratios of epoxy and diluent were 2:8 and 1:9, respectively, and in terms of strength improvement, when the ratios of epoxy and diluent were 2:8 and 3:7, respectively. showed similar excellence.

In summary, when the ratio of epoxy to diluent was 2:8, the inductance reduction rate was similar to that of 1:9, and the strength was similar to that of 3:7. This can be said to be the most desirable ratio.

Therefore, hereinafter, when the ratio of epoxy to diluent is 2:8, the epoxy ratio in the interlayer space will be examined in more detail with reference to FIGS. 12 and 13.

FIG. 12 is a diagram for explaining a sample measurement area according to an embodiment, and FIG. 13 shows measurement results according to the area of FIG. 12.

Referring to FIG. 12, a top view of the second magnetic material 820 that is dried after being impregnated with a coating solution having a dilution ratio of 2:8 according to an embodiment is shown. In order to measure the epoxy ratio of the interlayer space, one second magnetic material 820 is divided into four regions, Area_1 to Area_4, and a cross-sectional image cut in the circumferential direction of each is captured. Therefore, for one second magnetic material sample, the epoxy ratio in the interlayer space was measured four times, and a total of 20 measurements were performed using five samples.

Figure 13 shows images of some samples taken during this measurement process. Figure 13 shows an enlarged image of the cross-section after cutting the second magnetic material in the circumferential direction by impregnating a metal ribbon wound in 15 layers (turns) with an epoxy coating solution having a dilution ratio of 2:8. In addition, in FIG. 13, each image has a common bottom in a centrifugal direction, each top image indicates which part of the cross section the bottom image corresponds to, and the bottom image is an image further enlarged to show only the 5-layer metal ribbon. The circles in each bottom image indicate the area where the epoxy resin is located.

In Figure 13 (a), epoxy resin accounts for 15% of the interlayer space, in Figure 13 (b), 20%, in Figure 13 (c), 25%, and in Figure 13 (d), 30%. It is shown that epoxy accounts for each proportion.

In summary, when the dilution ratio is 2:8, the epoxy ratio in the interlayer space is 15% to 30%, but this is a range including the maximum and minimum values, and the results of 20 measurements are shown in Table 6 below.

Sample classification Area_1 Area_2 Area_3 Area_4 Total #One 15 25 30 25 #2 25 20 25 20 #3 25 15 25 20 #4 30 30 25 30 #5 25 25 20 25 average 24 23 25 24 24

Referring to Table 6, in a total of 20 experiments, 15% was shown twice, 20% was shown four times, 25% was shown seven times, and 30% was shown three times. Therefore, when the dilution ratio is 2:8, the epoxy ratio in the interlayer space may be 15% to 30%, preferably 20% to 25%, and more preferably 23% to 25%. In addition, although not shown, the thickness of the outer coating layer of the second magnetic material may be 10 mm to 40 mm, and preferably 20 mm to 30 mm. If the thickness is less than 10mm, the strength may be lowered and the metal ribbon may be damaged, and if it is greater than 40mm, the inductance reduction rate may increase and performance may be reduced.

Meanwhile, the inductor according to the above-described embodiment may be included in the line filter. For example, the line filter may be a noise reduction line filter applied to an AC-to-DC converter. Figure 14 is an example of an EMI filter including an inductor according to an embodiment.

Referring to FIG. 14, the EMI filter 2000 may include a plurality of X-capacitors (Cx), a plurality of Y-capacitors (Cy), and an inductor (L).

The X-capacitor (Cx) is between the first terminal (P1) of the live line (LIVE) and the third terminal (P3) of the neutral line (NEUTRAL) and between the second terminal (P2) of the live line (LIVE) and the neutral line ( NEUTRAL) are respectively disposed between the fourth terminals (P4).

A plurality of Y-capacitors (Cy) may be arranged in series between the second terminal (P2) of the live line (LIVE) and the fourth terminal (P4) of the neutral line (NEUTRAL).

The inductor (L) can be placed between the first terminal (P1) and the second terminal (P2) of the live line (LIVE) and between the third terminal (P3) and the fourth terminal (P4) of the neutral line (NEUTRAL). there is. Here, the inductor L may be the inductor 100 according to the above-described embodiment.

When common mode noise is introduced, the EMI filter 2000 removes the common mode noise using the composite impedance characteristics of the primary inductance and the Y-capacitor (Cy). Here, the primary inductance of the live line (LIVE) can be obtained by measuring the inductance between the first and second terminals (P1, P2) with the third and fourth terminals (P3, P4) open. The primary inductance of the neutral line (NEUTRAL) is obtained by measuring the inductance between the third and fourth terminals (P3, P4) with the first and second terminals (P1, P2) open. It can be.

When differential mode noise is introduced, the EMI filter 2000 removes the differential mode noise using leakage inductance and the composite impedance characteristics of the X-capacitor (Cx). Here, the leakage inductance of the live line (LIVE) can be obtained by measuring the inductance between the first and second terminals (P1 and P2) with the third and fourth terminals (P3 and P4) shorted. The leakage inductance of the neutral line (NEUTRAL) can be obtained by measuring the inductance between the third and fourth terminals (P3 and P4) with the first and second terminals (P1 and P2) short-circuited.

The inductor of the EMI filter 2000 according to the embodiment corresponds to the inductor according to the above-described embodiments.

The description of each of the above-described embodiments may also be applied to other embodiments as long as the contents do not conflict with each other.

Although the above description focuses on examples, this is only an example and does not limit the present invention, and those skilled in the art will understand that the examples are as follows without departing from the essential characteristics of the present example. You will see that various variations and applications are possible. For example, each component specifically shown in the examples can be modified and implemented. And these variations and differences in application should be construed as being included in the scope of the present invention as defined in the appended claims.

100: inductor
110: magnetic core
120: coil
800: Magnetic core
810: first magnetic body
820: Second magnetic body

Claims (7)

A ring-shaped first magnetic body including an outer peripheral surface and an inner peripheral surface;
It includes a second magnetic body disposed on at least a portion of the outer peripheral surface and the inner peripheral surface,
The second magnetic material is,
a metal ribbon arranged to form a plurality of layers along the centrifugal direction of the first magnetic material;
a first resin member arranged to cover the outer surface of the plurality of layers of metal ribbon; and
A second resin member disposed in at least a portion of the interlayer space of the plurality of layers,
A magnetic coupling device in which the radial thickness of the first magnetic material is thicker than the radial thickness of the second magnetic material. A ring-shaped first magnetic body including an outer peripheral surface and an inner peripheral surface;
It includes a second magnetic body disposed on at least a portion of the outer peripheral surface and the inner peripheral surface,
The second magnetic material is,
a metal ribbon arranged to form a plurality of layers along the centrifugal direction of the first magnetic material;
a resin portion surrounding the upper, lower, inner peripheral, and outer peripheral portions of the metal ribbon; and
It includes a first resin member and a second resin member disposed in different layers among the plurality of layers,
A magnetic coupling device in which the radial thickness of the first magnetic material is thicker than the radial thickness of the second magnetic material. According to claim 1 or 2,
A magnetic coupling device wherein the metal ribbon has a thickness of 15 mm to 20 mm. The magnetic coupling device of claim 1, wherein the radial thickness of the second magnetic material is thicker than the radial thickness of the first resin member. According to paragraph 4,
The first resin member is a magnetic coupling device having a thickness of 20 mm to 30 mm. The magnetic coupling device of claim 2, wherein the radial thickness of the second magnetic material is thicker than the radial thickness of the resin portion. According to clause 6,
A magnetic coupling device wherein the resin portion has a thickness of 20 mm to 30 mm.

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