KR20060136389A - Laminated coil - Google Patents

Abstract

The laminated body 9 formed on both main surfaces of the nonmagnetic body part 2 which the magnetic body part 1 which laminated | stacked the several magnetic body layers which consists of one or more nonmagnetic body layers, and the coil conductor 3 formed in the laminated body 9 ) And laminated coil provided with coil (L) which connected (4) in spiral form. At least one of coil conductors 3 formed on the laminate 9 and coil conductors 4 formed on both main surfaces of the nonmagnetic body 2 and the coil conductors formed inside the nonmagnetic body 2. The conductor width of the coil conductor is wider than the conductor width of the other coil conductor 3.

Laminated coil

Description

Laminated Coils {LAMINATED COIL}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to laminated coils, and in particular to open-loop laminated coils having excellent direct current superimposition characteristics.

Background Art Conventionally, in order to prevent magnetic saturation from occurring in a magnetic body and the inductance value drops rapidly in a laminated coil, an individual-type laminated coil has been proposed. As described in Patent Literature (1), an individual-type laminated coil forms a nonmagnetic layer inside a laminated coil formed of a magnetic layer. In the structure of the self-opening laminated coil, magnetic flux leaks from the portion of the nonmagnetic layer to the outside of the laminated coil, making it difficult to generate magnetic saturation in the magnetic body. As a result, the fall of inductance by DC current becomes small, and DC superimposition characteristic improves.

However, in the open-air type laminated coil of patent document (1), although the DC superposition characteristic was excellent, there existed a problem that the inductance characteristic was bad. That is, since the nonmagnetic layer is formed at a position through which the magnetic flux passes, the magnetic flux is blocked and the inductance is reduced. It is considered to increase the inductance by increasing the number of turns of the coil in order to obtain a desired inductance, but increasing the number of turns of the coil greatly increases the DC resistance.

Patent Document 1: Japanese Patent Application Laid-open No. Hei 1-35483

It is therefore an object of the present invention to provide a laminated coil having excellent direct current superimposition characteristics, suppressing the reduction of inductance and reducing the direct current resistance.

In order to solve the above problems, the laminated coil according to the present invention comprises: (a) a laminated body formed on both main surfaces of a nonmagnetic material portion in which a magnetic body portion in which a plurality of magnetic body layers are laminated is formed of at least one nonmagnetic layer, and (b) A coil having spirally connected coil conductors formed in the laminate, and (c) a coil conductor formed inside the nonmagnetic portion of the coil conductors formed in the laminate and coil conductors formed on both main surfaces of the nonmagnetic portion. A conductor width of at least one coil conductor is wider than that of other coil conductors.

DC resistance can be reduced by making the conductor width of one or more coil conductors of the coil conductors formed on both the inner surface of the nonmagnetic portion and the main surface of the nonmagnetic portion larger than that of the other coil conductors. In addition, by forming a coil conductor having a wide conductor width inside and / or on both main surfaces of the nonmagnetic portion, the reduction in inductance can be reduced even if the conductor width of the coil conductor is widened.

That is, in general, when the conductor width of the coil conductor is widened, the magnetic flux of the coil is blocked by the coil conductor having a wider conductor width, and the inner diameter of the coil is narrowed, so that the amount of magnetic flux passing through the coil decreases, thereby reducing the inductance. However, even if the conductor width of the coil conductor of the nonmagnetic portion is widened, the magnetic flux of the coil was originally blocked by the nonmagnetic portion, so that the magnetic flux of the coil further blocked by increasing the conductor width of the coil conductor is very small. In addition, even if the conductor width of the coil conductor is widened, the inner diameter of the coil in the nonmagnetic portion that blocks the magnetic flux becomes small, so that the decrease in the amount of the magnetic flux passes is small compared to that of the coil of the magnetic portion that allows the magnetic flux to pass. Lose. Therefore, the fall of the inductance of the whole coil can be made small.

In the laminated coil according to the present invention, the conductor width of the coil conductor formed inside the nonmagnetic portion and the coil conductor formed on both main surfaces of the nonmagnetic portion may be wider than the conductor width of the other coil conductor. By widening the conductor widths of the coil conductors formed on both the inner surface of the nonmagnetic portion and on both main surfaces of the nonmagnetic portion, a plurality of coil conductors having a wide conductor width can be formed, thereby greatly reducing the DC resistance.

Moreover, it is preferable that the laminated coil by this invention is 1.05-2.14 times the conductor width of the coil conductor from which the conductor width of the said coil conductor with wide conductor width differs. Thereby, the laminated coil which suppressed the fall of an inductance as much as possible and greatly reduced the DC resistance can be obtained.

In the multilayer coil according to the present invention, a plurality of nonmagnetic portions may be formed inside the laminate. By forming a plurality of nonmagnetic parts inside the laminate, the amount of magnetic flux leaking from the nonmagnetic parts to the outside of the laminated coil can be further increased, and the direct current superimposition characteristic can be improved.

As described above, according to the present invention, since the conductor width of one or more coil conductors among the coil conductors formed inside the non-magnetic portion and the coil conductors formed on both main surfaces of the non-magnetic portion is wider than that of the other coil conductors, it has excellent DC superposition characteristics. The laminated coil which suppressed the fall of inductance and reduced DC resistance can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the laminated coil in Example 1 of this invention.

Fig. 2 is an exploded perspective view of the laminated coil in the first embodiment of the present invention.

3 is a schematic cross-sectional view of a laminated coil of a conventional example.

4 is a schematic cross-sectional view of a laminated coil of Comparative Example 1. FIG.

5 is a schematic cross-sectional view of a laminated coil in a third embodiment of the present invention.

6 is a schematic cross-sectional view of a laminated coil in a fourth embodiment of the present invention.

7 is a schematic cross-sectional view of a laminated coil in a fifth embodiment of the present invention.

8 is a schematic cross-sectional view of a laminated coil of Comparative Example 2. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the Example of the laminated coil by this invention is described with reference to drawings.

(Example 1)

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the laminated coil in Example 1 of this invention. The laminated coil includes a laminated body 9 composed of the magnetic body part 1 and the nonmagnetic body part 2, a coil L having spirally connected the coil conductors 3 and 4 formed on the laminated body 9, and the outside. It is formed by the electrode 5. The magnetic body parts 1 are formed on both main surfaces of the nonmagnetic body parts 2. In addition, the magnetic body part 1 is comprised by the several magnetic body layer, and the nonmagnetic body part 2 is comprised by the one layer nonmagnetic body layer.

As shown in Fig. 1, the coil conductor 4 is formed on both main surfaces of the nonmagnetic portion 2, and the conductor width is wider than that of the coil conductor 3 having another predetermined conductor width. Since the conductor width of the coil conductor 4 is wide, the direct current resistance of a laminated coil falls.

Moreover, since the coil conductor 4 with a wide conductor width is formed in the both main surfaces of the nonmagnetic body part 2, the fall of inductance can be made small. That is, in general, when the conductor width of the coil conductor is widened, the magnetic flux of the coil is blocked by the coil conductor having a wider conductor width, and the inner diameter of the coil is narrowed, so that the amount of magnetic flux passing through the coil decreases, thereby reducing the inductance. However, even if the conductor widths of the coil conductors 4 on both main surfaces of the nonmagnetic part 2 are widened as in Example 1, since the magnetic flux of the coil L was originally blocked by the nonmagnetic part 2, the coil By increasing the conductor width of the conductor 4, the magnetic flux of the coil L which is further interrupted becomes very small. Further, even if the conductor width of the coil conductor 4 is widened, the inner diameter of the coil L in the nonmagnetic portion 2 which blocks the magnetic flux decreases, so that the coil L of the magnetic portion 1 passing the magnetic flux is small. The decrease in the amount of magnetic flux passing through is smaller, whereas the inner diameter of is smaller. Therefore, the fall of the inductance of the whole coil L can be made very small.

Next, the manufacturing method of a laminated coil is demonstrated using the exploded perspective view of the laminated coil shown in FIG.

In the manufacturing method of a laminated coil, the green sheet 6 using a magnetic body material and the green sheet 7 using a nonmagnetic material are produced initially. In addition, after forming a laminated coil, a magnetic green sheet becomes a magnetic layer, and a nonmagnetic green sheet becomes a nonmagnetic layer.

In Example 1, a Ni—Cu—Zn-based material was used as the magnetic material. First, the material was composed of 48.0 mol% of ferric oxide (Fe ₂ O ₃ ), 20.0 mol% of zinc oxide (ZnO), 23.0 mol% of nickel oxide (NiO), and 9.0 mol% of copper oxide (CuO). Wet combination is performed using a ball mill. The obtained mixture is dried and then ground, and the powder is calcined at 750 ° C. for 1 hour. Binder resin, a plasticizer, a wetting agent, and a dispersing agent are added to this powder, it mixes by a ball mill, and it defoases after that, and obtains a slurry. And this slurry is apply | coated on a peelable film and dried, and the magnetic green sheet 6 of desired film thickness is produced.

Moreover, Cu-Zn type material was used as a nonmagnetic material. A nonmagnetic green sheet was prepared by the same method as the above magnetic material using a ratio of 48.0 mol% of ferric oxide (Fe ₂ O ₃ ), 43.0 mol% of zinc oxide (ZnO), and 9.0 mol% of copper oxide (CuO). 7) to produce. On the other hand, the specific magnetic permeability of each green sheet is 130 for the magnetic green sheet 6 and 1 for the nonmagnetic green sheet 7.

Subsequently, each green sheet 6 and 7 obtained as mentioned above is cut | disconnected to predetermined | prescribed dimension, and a laser etc. are located in a predetermined position so that the spiral coil L may be formed after lamination | stacking of each green sheet 6 and 7. Form a through hole by the method of. The coil conductors 3 and 4 are formed on the magnetic green sheet 6a and the nonmagnetic green sheet 7 by applying a conductor paste mainly composed of silver or silver alloy by screen printing or the like. On the other hand, the via hole conductor 8 for a connection can be easily formed by filling a electrically conductive paste in the inside of a through hole simultaneously with formation of the coil conductors 3 and 4.

Here, the wide coil conductor 4 is formed so that it may be located in both main surfaces of the nonmagnetic green sheet 7. In the present Example 1, the wide coil conductor 4 was formed so that 550 micrometers and the conductor width of the other coil conductor 3 might be 350 micrometers after baking. By forming the wide coil conductor 4 on both main surfaces of the nonmagnetic green sheet 7, it is possible to obtain a laminated coil in which the inductance is reduced and the DC resistance is reduced.

And the magnetic green sheet 6a which formed the coil conductor 3 was laminated | stacked on both main surfaces of the nonmagnetic green sheet 7, and the magnetic green sheet 6b for outer layer which does not form the coil conductor up and down is arrange | positioned. This forms a laminated body. At this time, by stacking the nonmagnetic green sheet 7 so as to be positioned approximately in the center of the axial direction of the spiral coil L, the magnetic flux leaking to the outside of the laminated coil increases, so that the DC superposition characteristic can be improved.

Thereafter, the laminated body was pressed at 45 ° C. at a pressure of 1.Ot / cm 2 and cut into dimensions of 3.2 × 2.5 × 0.8 mm by a dicer or guillotine cutter to unbaked the laminated coil. Get Then, this binder is debindered and fired. The binder removed is heated at 500 ° C. for 2 hours in a low oxygen atmosphere, and the main firing is fired at 890 ° C. for 150 minutes in an air atmosphere. Finally, the electrode paste whose main component is silver is apply | coated to the end surface to which an extraction electrode is exposed by dipping, etc., and after drying at 100 degreeC for 10 minutes, it bakes at 780 degreeC for 150 minutes. Thereby, the laminated coil of Example 1 can be obtained.

Rdc (mΩ) Inductance (μH) Conventional example 185 2.00 Example 1 166 1.91 Comparative Example 1 150 1.56

Table 1 shows the test results performed to confirm the effect of the laminated coil of Example 1 obtained above. As shown in Fig. 3, the conventional coil is a laminated coil in which the conductor widths of the coil conductors 13 formed on the magnetic body portion 11 and the nonmagnetic body portion 12 are all 350 mu m. In addition, the comparative example is a multilayer coil of 550 micrometers in which the conductor width of the coil conductor 24 formed in the magnetic body part 21 and the nonmagnetic body part 22 is wide as shown in FIG. In addition, in all the laminated coils, the number of turns of the spiral coil L is 5.5 turns, and the size of the laminated coils is 3.2 mm x 2.5 mm x 2.5 mm.

It can be seen from Table 1 that the laminated coil of Example 1 has a reduced DC resistance and a small decrease in inductance. That is, while the DC resistance of the conventional example is 185 mΩ, the DC resistance of Example 1 is 166 mΩ, and the DC resistance is reduced by 10%. On the other hand, while the inductance of the conventional example is 2.0 µH, the inductance of Example 1 is 1.91 µH, which is reduced by only 4.5%. On the other hand, in the comparative example in which the conductor widths of all the coil conductors were widened, the DC resistance was reduced by 150 m? And 18%. However, the inductance was 1.56 µH and the decrease was as large as 22%. As described above, in Example 1, the conductor width of the coil conductor 4 was widened to reduce the direct current resistance, while reducing the inductance caused by widening the conductor width of the coil conductor 4 was wide. The coil conductor 4 is formed on both main surfaces of the nonmagnetic portion 2 which blocks the magnetic flux.

Conductor width of coil conductor located on both main surfaces of nonmagnetic material Conductor Width Ratio Rdc (mΩ) Inductance (μH) Conventional example 350㎛ 1.00 185 2.00 Sample 1 357 ㎛ 1.02 184 2.00 Sample 2 368 ㎛ 1.05 183 1.99 Sample 3 450㎛ 1.29 176 1.96 Sample 4 550㎛ 1.57 166 1.91 Sample 5 650㎛ 1.86 157 1.86 Sample 6 750㎛ 2.14 147 1.79 Sample 7 850 ㎛ 2.43 138 1.71

Next, Table 2 shows the evaluation results of Samples 1 to 7 in which the conductor widths of the coil conductors 4 formed on both main surfaces of the nonmagnetic portion 2 were changed. In Samples 1 to 7, the conductor widths of the coil conductors 4 formed on both main surfaces of the nonmagnetic portion 2 were changed to 357, 368, 450, 550, 650, 750, and 850 µm. On the other hand, the conventional example is a laminated coil in which the conductor widths shown in Fig. 3 are all the same 350 µm.

In Samples 2 to 6, the DC resistance decreases, and the inductance value is also preferable. On the other hand, in Sample 1 (conductor width ratio 1.02), the reduction rate of the DC resistance was very small, less than 1%. In addition, in Sample 7 (conductor width ratio 2.43), the reduction rate of the inductance value compared with the conventional example was greatly reduced to 14.5%.

(Example 2)

Although the structure of the laminated coil in Example 2 of this invention is the same as the structure of the laminated coil in Example 1 shown in FIG. 1, in this Example 2, it is located in the both main surfaces of the nonmagnetic body part 2. In FIG. The conductor width of the coil conductor 4 was 750 micrometers, and the conductor width 3 of the coil conductor 3 which is not located in the both main surfaces of the nonmagnetic body part 2 was 350 micrometers. On the other hand, the conventional example shown in the following Table 3 is a laminated coil in which the conductor width of the coil conductor 13 formed in the magnetic body part 11 and the nonmagnetic body part 12 is 350 micrometers as shown in FIG. In Comparative Example 2, as shown in Fig. 8, the coil conductors having different conductor widths of the coil conductors 34 (not formed on the inside of the magnetic body portion 31) which are not formed on both main surfaces of the nonmagnetic body portion 32 are shown. It is a laminated coil wider than (33), the conductor width of the coil conductor 34 with a wide conductor width is 750 micrometers, and the conductor width of the other coil conductor 33 is 350 micrometers.

Rdc (mΩ) Inductance (μH) Conventional example 185 2.00 Example 2 147 1.79 Comparative Example 2 147 1.53

As shown in Table (3), the laminated coil of Example 2 widens the conductor width of the coil conductors 4 located on both main surfaces of the nonmagnetic portion 2, so that the DC resistance is reduced in comparison with the conventional example. It is. And since the conductor width of the coil conductor 34 by the number of turns same as the laminated coil of Example 2 was made wide also in the laminated coil of the comparative example 2, DC resistance falls compared with the conventional example. However, the inductance of the laminated coil of Example 2 is 1.79 μH, and the inductance of the laminated coil of Comparative Example 2 is 1.53 μH, while the inductance of the laminated coil of Comparative Example 2 is reduced by only about 10%. % Decrease. Thus, the laminated coil of Example 2 was able to suppress the fall of inductance by forming the coil conductor 4 with a wide conductor width in the both main surfaces of the nonmagnetic body part 2 which interrupts a magnetic flux.

(Example 3)

In FIG. 5, schematic sectional drawing of the laminated coil in Example 3 of this invention is shown. 5, the same code | symbol is attached | subjected to the part common or corresponding to FIG. 1, and description is abbreviate | omitted suitably.

In the laminated coil of the third embodiment, the coil conductor 4 is formed inside the nonmagnetic portion 2, and the conductor width of the coil conductor 4 is wider than the conductor width of the other coil conductor 3. In addition, similarly to Example 1, the laminated coil of Example 3 is also manufactured by the method of laminating | stacking and crimping | bonding the green sheet which formed the coil conductor, cutting it with each chip, and forming an external electrode.

The DC resistance can be reduced by forming the coil conductor 4 with a wide conductor width. In addition, by forming the coil conductor 4 having a wide conductor width inside the nonmagnetic portion 2, the reduction in inductance can be reduced.

(Example 4)

In FIG. 6, schematic sectional drawing of the laminated coil in Example 4 of this invention is shown. 6, the same code | symbol is attached | subjected to the part common or corresponding to FIG. 1, and the description is abbreviate | omitted.

In the laminated coil of the fourth embodiment, the coil conductors 4 are formed on both the inner surface of the nonmagnetic portion 2 and the main surfaces of the nonmagnetic portion 2, and the conductor widths of the coil conductors 4 are different from each other. It is wider than the conductor width of the conductor 3.

The DC resistance can be reduced by forming the coil conductor 4 with a wide conductor width. In particular, in the fourth embodiment, since the coil conductor 4 having a wide conductor width is formed over three layers, a large direct current resistance can be reduced. In addition, by forming the coil conductor 4 having a wide conductor width on both the inner surface of the nonmagnetic portion 2 and the main surface of the nonmagnetic portion 2, the reduction in inductance can be reduced.

(Example 5)

Fig. 7 shows a schematic cross-sectional view of the laminated coil in the fifth embodiment of the present invention. In addition, in FIG. 7, the same code | symbol is attached | subjected to the part common or corresponding to FIG. 1, and the description is abbreviate | omitted.

In the laminated coil of the fifth embodiment, two nonmagnetic portions 2 are formed inside the laminated body 9. And the coil conductor 4 is formed in the both main surfaces of the nonmagnetic body part 2, and the conductor width of the coil conductor 4 is wider than the conductor width of the other coil conductor 3. As shown in FIG.

Since the two nonmagnetic parts 2 are formed inside the laminated body 9, the amount of magnetic flux leaking out of the laminated coil can be increased, and the direct current superimposition characteristic can be improved. In addition, the DC resistance can be reduced by forming the wide coil conductor 4. In particular, in the fifth embodiment, since the coil conductor 4 having a wide conductor width is formed over four layers, a large direct current resistance can be reduced. Moreover, the fall of inductance can be made small by forming the coil conductor 4 with a wide conductor width on both main surfaces of the nonmagnetic body 2. As shown in FIG.

(Other Examples)

In addition, the laminated coil of this invention is not limited to the said Example, It can change variously within the range of the summary.

For example, the conductor width of one coil conductor of the coil conductor formed on both main surfaces of the nonmagnetic portion may be wide. In addition, the conductor width of one or more coil conductors of the coil conductor formed inside the nonmagnetic portion and the coil conductor formed on both main surfaces of the nonmagnetic portion may be wider than the conductor width of the coil conductor of the other main portion.

As described above, the present invention is useful for an individual-type laminated coil, and is particularly excellent in that it has excellent direct current superimposition characteristics, suppresses a decrease in inductance, and can also reduce direct current resistance.

Claims (4)

A laminated body formed on both main surfaces of a nonmagnetic body portion, in which a magnetic body portion in which a plurality of magnetic body layers are laminated is formed of at least one nonmagnetic layer; A coil having spirally connected coil conductors formed in the laminate; Among the coil conductors formed in the laminate, a conductor width of one or more coil conductors of a coil conductor formed inside the nonmagnetic portion and a coil conductor formed on both main surfaces of the nonmagnetic portion is wider than that of other coil conductors. Laminated coils. The method of claim 1, The coil width formed inside the nonmagnetic part and the coil width formed on both main surfaces of the nonmagnetic part are wider than the conductor widths of the other coil conductors. The method according to claim 1 or 2, The conductor width of the coil conductor having a wider conductor width is 1.05 to 2.14 times the conductor width of the other coil conductor. The method according to any one of claims 1 to 3, Laminated coil, characterized in that a plurality of the non-magnetic portion formed in the laminate.

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