JPH11102817A - Inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductor capable of lowering the development of leakage flux and which has a good characteristic. SOLUTION: This inductor 21 comprises one to a plural ceramic sheets 23, consisting of a nonmagnetic ceramic material forming a ring-shaped magnetic material pattern 22, ceramic sheets 26 and 27 consisting of a non-magnetic ceramic material respectively forming coil conductors 24a and 24b, and 25a and 25b, a protective ceramic sheet 28, and the like. Each conductors of the coil conductor pattern 24a and each conductor of the coil conductor pattern 25a are alternately connected successively through a via hole 29 and forms a coil La. Each conductor of the coil conductor pattern 24b and each conductor of the coil conductor pattern 25b are connected alternately successively through the via hole 29 and forms a coil Lb. The magnetic material pattern 22 forms a toroidal core. Then the coils La and Lb are wound around the toroidal core.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor, and more particularly to an inductor such as a laminated transformer or a common mode choke coil.

[0002]

2. Description of the Related Art Conventionally, as this kind of inductor, for example, an inductor shown in FIG. 8 is known. This inductor is called a common mode choke coil having a function of blocking the passage of in-phase noise having the same phase. The inductor is a coil conductor 11a, 1
The magnetic ceramic sheet 12 having the surface printed with 1b, the magnetic ceramic sheet 14 having the coil conductors 13a and 13b printed on the surface, the magnetic ceramic sheet 16 having the coil conductors 15a and 15b printed on the surface, and the protective magnetic ceramic sheet 17 to form a laminate.
Coil conductors 11a, 13a, 15a and coil conductor 11
The b, 13b, and 15b are sequentially electrically connected via via holes 18 provided in the sheets 12, 14, and form solenoid-shaped coils La and Lb, respectively.

[0003]

However, in the conventional inductor, the coils La and L are formed in a laminate made of a magnetic material.
Since b is built in, the magnetic flux generated around the coils La and Lb spreads over the entire laminated body which is the magnetic path. For this reason, there is a problem that a large amount of magnetic flux leaks out of the laminated body, and when a conventional inductor is mounted on a printed circuit board or the like, the magnetic flux leaks undesirably affects other electronic components.

[0004] Also, a conventional laminated type transformer is generally known to have a configuration similar to that of the common mode choke coil. However, in a conventional transformer having such a configuration, the primary coil is connected to the primary coil by the leakage magnetic flux. There was a problem that the coupling coefficient with the secondary coil was small.
Then, when the primary coil and the secondary coil are brought closer to increase the coupling coefficient, there is a problem that the withstand voltage between them decreases, and the reliability of the transformer decreases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inductor which generates less leakage magnetic flux, has good characteristics, and is highly reliable and easy to manufacture.

[0006]

In order to achieve the above object, an inductor according to the present invention comprises a magnetic material having a predetermined shape, a plurality of coil conductors, and a ceramic layer made of a plurality of non-magnetic materials. A plurality of coils formed by stacking and forming a laminate, and electrically connecting the coil conductors, are incorporated in the laminate in a state wound around the magnetic body.

[0007]

According to the above construction, the magnetic material functions as a core of the coil and forms a magnetic path through which a magnetic flux generated around each coil passes. Since the magnetic material is locally disposed in the non-magnetic material of the laminate, the magnetic flux generated around each coil does not spread over the entire laminate, and the magnetic flux leaking out of the laminate is reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an inductor according to the present invention will be described below with reference to the accompanying drawings.

[First Embodiment, FIGS. 1 to 3] As shown in FIG. 1, an inductor 21 is made of a non-magnetic ceramic material having a ring-shaped magnetic pattern 22 made of a magnetic material on the surface. Multiple ceramic sheets 23
And coil conductor patterns 24a, 24b and 25 on the surface.
a and 25b are formed of ceramic sheets 26 and 27 made of a non-magnetic ceramic material, and a protection ceramic sheet 28 made of a non-magnetic ceramic material. Ceramic sheets 23, 26-28
As the material, a nonmagnetic insulator material or the like is used.
The magnetic pattern 22 is made of, for example, a Ni—Zn-based or Ni—C
It is formed from a u-Zn-based magnetic material.

In this case, in order to increase the sectional area of the magnetic material pattern 22 and prevent the magnetic material pattern 22 from projecting from the surface of the ceramic sheet 23, the magnetic material pattern 22 is not simply formed on the surface of the ceramic sheet 23, A ring-shaped groove 23a (see FIG. 2) is formed on the surface with a laser or the like, and the inside of the groove 23a is filled with a magnetic material using a method such as printing to form a magnetic pattern 22 or a ceramic sheet 23. Alternatively, a ring-shaped through hole (not shown) may be formed, and a magnetic material may be filled in the through hole to form a magnetic pattern (the same applies hereinafter). By doing so, the electrical characteristics of the inductor 21 can be improved.

Each conductor of the coil conductor pattern 24a and each conductor of the coil conductor pattern 25a are connected to via holes 29 provided in the sheets 23 and 27 as shown by dotted lines in FIG.
Are sequentially and alternately connected to each other to form a coil La.
Similarly, the conductors of the coil conductor pattern 24b and the conductors of the coil conductor pattern 25b are sequentially and alternately connected via via holes 29 provided in the sheets 23 and 27 to form the coil Lb. The coil conductor patterns 24a, 24b and 25a, 25b are formed on the sheets 26, 27 by using a conductive paste such as Ag, Ag-Pd, or Cu by a printing method or the like.

Each of the ceramic sheets 23, 26 to 28 is
The sheets 26 and 27 are respectively stacked on the lower side and the upper side of the plurality of sheets 23, and the sheets 28 and 28 are further stacked on the lower side and the upper side of the sheets 26 and 27, respectively. This is a laminate 31 (see FIG. 2). Terminal electrodes 1a and 2a of the coil La are provided on the left end face of the laminated body 31, and terminal electrodes 1b and 2b of the coil Lb are provided on the right end face. Terminal electrodes 1a, 2a
Are electrically connected to the coil conductor patterns 24a and 25a, respectively, and the terminal electrodes 1b and 2b are electrically connected to the coil conductor patterns 24b and 25b, respectively. These electrodes 1a to 2b are formed by applying and baking a conductive paste such as Ag or Ag-Pd to the left and right end portions of the laminate 31.

The multilayer inductor 21 having the above configuration
As shown in FIG. 2, coils La and Lb having axes perpendicular to the laminating direction of the ceramic sheets 23 and 26 to 28 are formed inside a laminate 31. Sheet 23
The plurality of magnetic body patterns 22 stacked via
The toroidal core 22a is formed. The coil La is wound around the left portion of the toroidal core 22a, and the coil Lb is wound around the right portion. Therefore, the magnetic body pattern 22 is formed by the coils La and Lb.
Function as a core 22a that forms a closed magnetic path penetrating through.

As described above, the magnetic pattern 22 forms a closed magnetic path linking the two coils La and Lb, and serves as a magnetic path through which the magnetic flux generated around each of the coils La and Lb passes. The magnetic pattern 22 is locally disposed in the non-magnetic material formed by the sheets 23 and 26 to 28 of the laminate 31, and the magnetic flux generated around each of the coils La and Lb is Since it does not spread over the entirety of 31, the magnetic flux leaking out of the inductor 21 can be reduced. As a result, it is possible to prevent the leakage magnetic flux from adversely affecting other electronic components. FIG. 3 shows inductor 2
1 is an electrical equivalent circuit diagram of FIG.

Further, in the case of the transformer having the above-described configuration, since the coupling coefficient between the primary coil and the secondary coil increases, excellent transformer characteristics can be obtained. In addition, since the magnetic material pattern 22 constitutes the core 22a of the closed magnetic circuit to obtain a large coupling coefficient, the distance between the primary coil and the secondary coil can be increased, and a transformer having excellent withstand voltage characteristics can be obtained. Can also.

It is not always necessary to use a plurality of magnetic material patterns 22, but one (one layer) may be used. However, if a plurality of magnetic material patterns 22 are used, the sectional area of the core 22a can be easily increased. And the magnetic flux density at which the core 22a is saturated can be easily increased. As a result,
When the inductor 21 is a common mode choke coil, large common mode noise can be removed. When the inductor 21 is a transformer, a transformer having a large capacity can be obtained.

[Second Embodiment, FIG. 4] As shown in FIG. 4, the inductor of the second embodiment is made of a non-magnetic material, and has one or more ceramics on which a sun-shaped magnetic pattern 42 is formed. A sheet 43 (see FIG. 4C) forms a sun-shaped core 42a, and a ceramic sheet 45 (see FIG. 4D) on which a coil conductor pattern 44 is formed below the ceramic sheet 43. A protective ceramic sheet 46 (see FIG. 4E) and a ceramic sheet 48 on which a coil conductor pattern 47 is formed on the upper side.
(See FIG. 4B) and the protective ceramic sheet 46
(See FIG. 4 (A)) are laminated, pressed and fired. Around the middle leg of the sun-shaped core 42a, three coils La formed by electrically connecting coil conductor patterns 44 and 47 via via holes 49 formed in the sheets 43 and 48. , Lb and Lc are wound.

The inductor of the second embodiment also has a core 4
2a forms a closed magnetic path linking the three coils La, Lb, Lc, and is a magnetic path through which magnetic flux generated around each of the coils La to Lc passes. This core 42a is made of
Since the magnetic flux generated around the coils La to Lc is locally disposed in the non-magnetic material formed by the sheets 43, 45, 46, and 48 and does not spread over the entire laminate, the first embodiment The same operation and effect as those of the inductor 21 having the form can be obtained.

[Third Embodiment, FIG. 5] As shown in FIG. 5, the inductor of the third embodiment is made of a non-magnetic material and has two open-ended magnetic patterns 52a and 52b. The two core-shaped cores 51a and 51 are formed by a plurality of ceramic sheets 53 (see FIG. 5C).
b, and a ceramic sheet 55 (see FIG. 5D) and a protective ceramic sheet 56 (see FIG. 5E) on which the coil conductor patterns 54a and 54b are formed below the ceramic sheet 53. On the upper side, a ceramic sheet 58 (see FIG. 5B) on which coil conductor patterns 57a and 57b are formed and a protective ceramic sheet 56 (see FIG. 5A) are laminated and fired. It was done.

Around each of the two legs of the two mouth-shaped cores 51a, 51b, coil conductor patterns 54a, 5b are provided.
Four coils La, Lb, Lc, Ld formed by electrically connecting 7a and 54b, 57b via via holes 59 formed in sheet 53 and sheet 58.
Is wound. Then, the core 51a and the coils La, L
b constitutes, for example, a common mode choke coil 60a, and the core 51b and the coils Lc, Ld constitute a common mode choke coil 60b.

In the inductor of the third embodiment, each of the two cores 51a and 51b has a coil La, Lb and a coil L
c, Ld to form a closed magnetic path, and each coil L
A magnetic path through which the magnetic flux generated around a to Ld passes. These cores 51a, 51b are made of sheets 53, 5 of a laminate.
Since the magnetic flux generated around the coils La to Ld is not locally spread in the entire laminated body, the inductor according to the first embodiment is locally disposed in the non-magnetic body formed by 5, 56, 58. The same operation and effect as those described above can be obtained, and a plurality of common mode choke coils 60a and 60b can be provided.
Can be obtained.

[Fourth Embodiment, FIG. 6] As shown in FIG. 6, an inductor according to a fourth embodiment is made of a non-magnetic material and has one or more ceramic sheets on which an I-shaped magnetic pattern 62 is formed. 63 (see FIG. 6C), an I-shaped core 61 is formed, and the ceramic sheet 6 is formed.
A ceramic sheet 65 (see FIG. 6D) and a protective ceramic sheet 66 (see FIG. 6E) on which a coil conductor pattern 64 is formed, and a coil conductor pattern 67 on the upper side. Formed ceramic sheet 68
(See FIG. 6B) and the protective ceramic sheet 66
(See FIG. 6A) are laminated and fired. The three coils La, Lb, and Lc formed by electrically connecting the coil conductor patterns 64 and 67 to the I-shaped core 61 via the via holes 69 formed in the sheets 63 and 68 are wound around the I-shaped core 61. ing.

Also in the inductor of the fourth embodiment, the core 61 forms a magnetic path penetrating the three coils La, Lb, Lc, and becomes a magnetic path through which the magnetic flux generated around each of the coils La to Lc passes. . The core 61 is made of a sheet 6 of a laminate.
Since the magnetic flux generated around the coils La to Lc is locally disposed in the non-magnetic body formed by the layers 3, 65, 66, and 68 and does not spread over the entire laminated body, the first embodiment The same operational effects as those of the inductor can be obtained.

[Other Embodiments] The inductor according to the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the gist.

For example, the magnetic pattern 2 of the first embodiment
Instead of having a ring shape as shown in FIG. 2, a magnetic pattern 72 in which a plurality of arc-shaped patterns 71, 71,... Are arranged in a ring shape can be used as shown in FIG.

Further, in the above-described embodiment, a plurality of coils are individually wound around the magnetic body. However, a so-called bifilar winding in which a plurality of coils are wound around the magnetic body collectively is also possible. Good.

In the above embodiment, the ceramic sheets on which the respective patterns are formed are stacked and then integrally fired, but the invention is not necessarily limited to this. A ceramic sheet that has been fired in advance may be used. Further, the inductor may be manufactured by a manufacturing method described below. For example, in the first embodiment,
The inductor 21 sequentially prints the lower ceramic layer 26 with a paste-like ceramic sheet material, and coats the coil conductor patterns 24 a and 2 on the surface of the ceramic layer 26.
4b, the ceramic layer 23, the magnetic pattern 22, the ceramic sheet 23, the magnetic pattern 22,..., The upper ceramic sheet 27, and the conductor patterns 25a and 25b. After the formation of the intermediate laminate, a hole is formed through the intermediate laminate, and the via hole 29 is formed by filling the hole with a paste-like conductive paste. Next, the inductor 21 having a laminated structure can be manufactured by printing the protective ceramic layers 28 on the upper and lower surfaces of the intermediate laminate.

[0028]

As is clear from the above description, according to the present invention, a magnetic body having a predetermined shape, a plurality of coil conductors, and a ceramic layer made of a plurality of non-magnetic materials are stacked. And a plurality of coils formed by electrically connecting coil conductors were wound around the magnetic body and built into the laminate, so that the magnetic body functions as a coil core, and A magnetic path through which the magnetic flux generated around passes. Since this magnetic material is locally disposed in the non-magnetic material of the laminate, the magnetic flux generated around each coil does not spread to the entire laminate, and the magnetic flux leaking out of the laminate can be reduced. it can. As a result, it is possible to prevent the leakage magnetic flux from adversely affecting other electronic components.
Further, in the transformer having such a configuration, since the coupling coefficient between the primary coil and the secondary coil increases, excellent transformer characteristics can be obtained. In addition, a toroidal coil having high reliability and performance can be easily manufactured by the laminated structure.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of an inductor according to the present invention.

FIG. 2 is a schematic configuration diagram of the inductor of FIG. 1;

FIG. 3 is an electrical equivalent circuit diagram of the inductor shown in FIG.

4A and 4B show a sheet constituting a second embodiment of the inductor according to the present invention, wherein FIG. 4A shows an upper protective ceramic sheet, and FIG. 4B shows a ceramic sheet provided with an upper coil conductor pattern; , (C) shows a ceramic sheet provided with a magnetic material pattern, (D) shows a ceramic sheet provided with a lower coil conductor pattern, and (E)
FIG. 4 is a plan view showing a lower protective ceramic sheet.

5A and 5B show a sheet constituting a third embodiment of the inductor according to the present invention, wherein FIG. 5A shows an upper protective ceramic sheet, and FIG. 5B shows a ceramic sheet provided with an upper coil conductor pattern. , (C) shows a ceramic sheet provided with a magnetic material pattern, (D) shows a ceramic sheet provided with a lower coil conductor pattern, and (E)
FIG. 4 is a plan view showing a lower protective ceramic sheet.

6A and 6B show a sheet constituting a fourth embodiment of the inductor according to the present invention, wherein FIG. 6A shows an upper protective ceramic sheet, and FIG. 6B shows a ceramic sheet provided with an upper coil conductor pattern; , (C) shows a ceramic sheet provided with a magnetic material pattern, (D) shows a ceramic sheet provided with a lower coil conductor pattern, and (E)
FIG. 4 is a plan view showing a lower protective ceramic sheet.

FIG. 7 is a plan view showing a modification of the magnetic material pattern.

FIG. 8 is an exploded perspective view showing a conventional inductor.

[Explanation of symbols]

21: Inductor 22, 42, 52a, 52b, 62 ... Magnetic pattern 22a, 42a, 51a, 51b, 61 ... Core 23, 26, 27, 28, 43, 45, 48, 53, 5
5, 58, 63, 65, 68 ... ceramic sheets 24a, 24b, 25a, 25b, 44, 47, 54
a, 54b, 57a, 57b, 64, 67 ... coil conductor pattern 29, 49, 59, 69 ... via hole

Claims (1)

[Claims] 1. A laminate comprising a magnetic body having a predetermined shape, a plurality of coil conductors, and a plurality of ceramic layers made of a non-magnetic material, which are stacked to form a laminate, and the coil conductors are electrically connected. An inductor characterized in that a plurality of coils described above are incorporated in the laminate in a state wound around the magnetic body.