JP2004303776A - Stacked common mode choke coil and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-manufacture stacked common mode choke coil having a simple structure and exhibiting good noise removing characteristics. <P>SOLUTION: On the upper surface 12 and lower surface 13 of a magnetic body layer 11 formed by laying two magnetic body sheets 20 and 30 in layer, a first coil 15 and a second coil 16 being connected electrically through a through hole 14 are formed by lateral bifilar winding orthogonal to the thickness of the magnetic body layer 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laminated common mode choke coil for removing common mode noise that enters an electronic device and a method of manufacturing the same.
[0002]
[Prior art]
Conventionally, a USB (Universal Serial Bus), an IEEE 1394 (Institute of Electrical and Electronics Engineers 1394), and an LDVS (Low Voltage Differential) digital signal transmission such as an LDVS (Low Voltage Differential) are used in personal computers and their peripheral devices. Common mode choke coils are used to remove common mode noise.
[0003]
This common mode choke coil is a coil in which two or more coils are magnetically combined, and removes only the common mode component without affecting the normal mode component in the current conduction direction. It is configured as follows. That is, it is necessary to minimize the impedance of the normal mode and increase the impedance of the common mode as much as possible.
[0004]
As a conventional common mode choke coil, there is a coil in which first and second coil electrodes (vertical winding) are formed on layers different from each other in a thickness direction of a laminated body so as to overlap in a plan view. (For example, see Patent Document 1)
[0005]
Further, as another conventional technique, a magnetic sheet laminate in which a plurality of magnetic sheets each having a conductor line formed on the surface is laminated, and one horizontal winding coil in a predetermined pattern is formed by connecting the conductor lines. Are bonded via an insulator sheet. With such a configuration, a pair (two) of coils having the same number of turns and the same winding direction are formed on both sides of the insulator sheet with the insulator sheet interposed therebetween, so that most of the magnetic field generated by one of the coils is formed. Coupling with the other coil increases the coupling coefficient between the two coils. (For example, see Patent Document 2)
[0006]
[Patent Document 1]
JP-A-8-335517 (paragraph number 0017-0029, FIGS. 1 to 3)
[Patent Document 2]
JP-A-5-347215 (Paragraph No. 0013-0034, FIGS. 1-4)
[0007]
[Problems to be solved by the invention]
By the way, in the prior art described in Patent Document 1 described above, two coils are formed so as to overlap in the thickness direction of the laminate in a plan view. Need to be laminated so as not to cause the problem. For this reason, since it is necessary to laminate with high precision at the time of manufacturing, there is a disadvantage that the manufacturing process becomes complicated and labor and manufacturing costs are increased.
[0008]
Further, in the related art described in Patent Document 2, a plurality of magnetic sheets are stacked and a predetermined coil pattern is formed on a pair of magnetic sheet laminates, and an insulating sheet is interposed between the laminated sheets. . For this reason, it is necessary to form a plurality of magnetic sheets having different conductor line patterns, and there is a problem that a plurality of pattern forming apparatuses (steps) are required, which complicates the manufacturing process.
[0009]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated common mode choke coil having good noise removal characteristics, a simple structure, and easy manufacture, and a method of manufacturing the same.
[0010]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
The multilayer common mode choke coil according to claim 1, wherein the first and second magnetic layers are formed by laminating one or a plurality of magnetic sheets, and the first and second magnetic layers are electrically connected to each other through through holes. The second coiled conductor line is formed in a bifilar winding in a horizontal winding direction perpendicular to the thickness of the magnetic layer.
[0011]
According to the laminated common mode choke coil of the first aspect, the first and second coiled conductor lines electrically connected to the upper surface and the lower surface of the magnetic layer via the through holes are formed of the magnetic material layer. Since it is formed in a bifilar winding in the horizontal winding direction orthogonal to the thickness of the layer, the ratio of the coil-shaped conductor line on the winding surface can be small, and the number of windings can be easily increased while keeping the size small.
[0012]
In the multilayer common mode choke coil according to the second aspect, in the multilayer common mode choke coil according to the first aspect, the first and second coil-shaped conductor lines are alternately arranged such that their ends are aligned on one surface. A pair of magnetic sheets or layers provided with the same length of electrode line segments that are disposed in parallel at the same interval and that are to be through-hole connecting portions except for the positions where the ends are connected to external electrodes. The through holes are aligned so that the positions of the through holes are aligned and the back surfaces of the through holes are attached to each other.
[0013]
According to the laminated common mode choke coil of claim 2, the ends are arranged in parallel at the same interval alternately with the ends aligned on one surface, and the ends excluding the positions connected to the external electrodes are through holes. A pair of magnetic layers having the same length of electrode line serving as a connecting portion are laminated so that the through holes are aligned and the back surfaces of the magnetic layers are attached to each other to form a first and a second coil. Since the conductor line is formed, only one type of pattern is required for the electrode line segments (part of the coil-shaped conductor line) formed on the magnetic layer. In addition, since the two coiled conductor lines are stacked so that the back surfaces of the same coil members are aligned with each other and aligned with through holes, the overlapping accuracy is high.
[0014]
4. A method of manufacturing a laminated common mode choke coil according to claim 3, wherein a predetermined number of through holes are formed at predetermined positions of a magnetic layer formed by laminating one or more magnetic sheets. Forming a conductive line forming first and second coiled conductive lines on the surface of the magnetic layer and forming an external electrode connecting portion; and forming the through hole, the electrode line and the external electrode A pair of the magnetic material layers having the formed portions are prepared, the through holes are aligned, and the back surfaces of the magnetic material layers are laminated together, and a cover sheet made of a magnetic material is laminated on the upper and lower surfaces. A laminate forming step of integrally baking the laminate, and an external electrode forming step of forming an external electrode conducting to the external electrode connection portion. And it is characterized in and.
[0015]
According to such a method of manufacturing a laminated common mode choke coil, a through hole drilling step of drilling a predetermined number of through holes at predetermined positions of the magnetic layer, and the first and second through holes on the surface of the magnetic layer. A conductive line forming step of forming an electrode line segment and an external electrode connection portion that becomes a coiled conductive line, and a pair of magnetic layers on which a through hole, an electrode line segment, and an external electrode connection portion are formed are prepared. And a stacking step of stacking the cover sheets made of a magnetic material on both upper and lower surfaces to form a stacked body. In the process, only one type of pattern is required for the electrode line segment and the external electrode connection portion formed on the magnetic layer, and the manufacturing process can be simplified.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a multilayer common mode choke coil and a method of manufacturing the same according to the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the multilayer common mode choke coil of the present invention, FIG. 2 is an external perspective view of the multilayer common mode choke coil showing the completed state of FIG. 1, and FIG. It is explanatory drawing which shows a manufacturing process (method).
[0017]
In a laminated common mode choke coil (hereinafter, referred to as a “choke coil”) 10 shown in FIG. 1, through-holes are formed on an upper surface 12 and a lower surface 13 of a magnetic layer 11 formed by laminating two magnetic sheets 20 and 30. A first coiled conductor line (hereinafter, referred to as “first coil”) 15 and a second coiled conductor line (hereinafter, referred to as “second coil”) 16 electrically connected via the hole 14. Are formed by bifilar winding in a horizontal winding direction orthogonal to the thickness of the magnetic layer 11.
[0018]
As the magnetic sheet 20, for example, a magnetic green sheet is used. On the surface of the magnetic material sheet 20, that is, on one surface that becomes the upper surface 12 of the magnetic material layer 11, electrode segments 21, 22, 23, and 24 that are part of the first coil 15 and the second coil 16 are provided. It is formed by a known method such as printing a conductor. The electrode line segments 21 and 23 become a part of the first coil 15, and the electrode line segments 22 and 24 become a part of the second coil 16.
These electrode line segments have their ends aligned along one side of the rectangular magnetic material sheet 20 and are alternately arranged in parallel at the same interval. The lengths of the electrode segments 21, 22, 23, 24 are all the same, and external electrode connection portions 25, 26 are electrically connected to the electrode segments 21, 24 located at both ends arranged in parallel. It is formed by being electrically connected.
[0019]
In the illustrated example, a total of six through holes 14 are formed in the surface of the magnetic sheet 20. These through holes 14 are arranged in a zigzag pattern at three pitches on a pair of parallel virtual straight lines.
Then, the end portions are made to coincide with the above imaginary straight line, that is, the pair of through holes 14 are connected to each other, so that the electrode segments 21 of the same length which are part of the first coil 15 and the second coil 16 are formed. , 22, 23, and 24 are alternately formed two by two and in parallel at the same interval. However, each of the one electrode line segments 21 and 24 located at both ends of the parallel arrangement does not have the through hole 14 at one end, and is electrically connected to the external electrode connection portions 25 and 26 at the same position instead. It is connected to the.
[0020]
The magnetic material layer 11 is obtained by laminating the magnetic material sheet 30 on the back surface of the above-described magnetic material sheet 20, that is, on the surface on which the electrode segments are not formed.
Here, the magnetic sheet 30 will be described. The magnetic sheet 30 is the same as the above-described magnetic sheet 20 and has the same electrode line segments, external electrode connection portions, and through holes. Here, the electrode line segments 31 and 32 are used to classify both. , 33, 34 and external electrode connection portions 35, 36. However, the electrode segments 21 and 31, the electrode segments 22 and 32, the electrode segments 23 and 33, the electrode segments 24 and 34, the external electrode connection portions 25 and 35, and the external electrode connection portions 26 and 36 are substantially the same. The magnetic sheet 30 is a state where the magnetic sheet 20 is turned upside down.
[0021]
Therefore, all the through holes 14 are aligned, and the magnetic material layer 11 is formed by laminating the back surface of the magnetic material sheet 20 and the back surface of the magnetic material sheet 30 so as to be laminated. 14 is filled with a conductor by a known method such as vacuum deposition or metal plating.
As a result, the electrode line segments 21 to 24 and 31 to 34 formed on the magnetic material sheet 20 and the magnetic material sheet 30, respectively, are electrically connected via the conductor filled in the through-hole 14, and are each connected. The first coil 15 and the second coil 16 are independent. Therefore, the first coil 15 and the second coil 16 are a pair of coils formed in a bifilar winding in a horizontal winding direction orthogonal to the thickness (the laminating direction) of the magnetic layer 11.
[0022]
That is, the first coil 15 is electrically connected to the external electrode connecting portion 25, the electrode line segment 21, the electrode line segment 33, the electrode line segment 23, the electrode line segment 31, and the external electrode 35 via the through holes 14. In addition, the second coil 16 includes an external electrode connecting portion 36, an electrode line segment 34, an electrode line segment 22, an electrode line segment 32, an electrode line segment 24, and an external electrode 26, each of which passes through a through hole 14. And one electrically connected coil.
[0023]
The magnetic material layer 11 on which the magnetic material sheets 20 and 30 are laminated as described above is a laminate in which the cover sheet 17 is appropriately laminated on the upper surface 12 and the lower surface 13 as necessary, and this is integrally fired. After that, the external electrodes 18 and 19 are formed on the side surfaces to form the choke coil 10. One external electrode 18 is electrically connected to the external electrode connection portions 25 and 35 of the first coil 15, and the other external electrode 19 is electrically connected to the external electrodes 26 and 36 of the second coil 16. I have.
[0024]
Next, a method for manufacturing the above-described choke coil 10 will be described with reference to FIG.
FIG. 3A shows a magnetic sheet 20 such as a green sheet to be the magnetic layer 11, which is cut into a predetermined shape such as a rectangle. In the following description, it is assumed that one choke coil 10 is manufactured from one magnetic material sheet 20, 30. However, a plurality of pieces are simultaneously formed on one sheet, and then cut and divided. May be adopted.
[0025]
In the through hole drilling step shown in FIG. 3B, a predetermined number of through holes 14 are drilled at predetermined positions of the magnetic sheets 20 and 30. The through holes 14 penetrate the magnetic sheets 20 and 30, and may be formed by using a known method such as laser or punching.
[0026]
In the conductive line forming step shown in FIG. 3C, the electrode segments 21 to 24, 31 to 34 that become a part of the first coil 15 and the second coil 16 and the external electrode connection are formed on the surfaces of the magnetic sheets 20 and 30. The parts 25, 26, 35, 36 are formed. These conductive lines are formed in a predetermined shape and arrangement by a known method such as screen printing of a conductive paste.
[0027]
In the laminated body forming step shown in FIG. 3D, a pair of magnetic sheets 20, on which the through holes 14, the electrode segments 21 to 24, 31 to 34, and the external electrode connecting portions 25, 26, 35, 36 are formed, 30 are prepared, the through holes 14 are aligned, and the back surfaces of the through holes 14 are laminated to form the magnetic layer 11. After the magnetic layer 11 is formed, the through holes 14 are filled with a conductor, and the respective electrode lines are electrically connected.
[0028]
Thereafter, as shown in FIG. 3E, a cover sheet 17 made of a magnetic material is overlapped on the upper surface 12 and the lower surface 13 of the magnetic material layer 11 as necessary, respectively, and the four layers shown in FIG. This is referred to as a laminate S.
The laminate S is integrally fired in the next laminate firing step, for example, by being put in a firing furnace and exposed to an environment at a predetermined temperature for a predetermined time.
[0029]
In the fired body of the laminate S obtained in this manner, in the next external electrode forming step, the external electrodes 18 and 19 which are respectively connected to the external electrode connecting portions 25, 26, 35 and 36 are formed, and the choke coil 10 is obtained. The external electrodes 18 and 19 can be easily formed by employing a known method such as applying and baking a conductive paste or attaching a metal cap.
[0030]
In the choke coil 10 having the above-described configuration and manufactured by the above-described manufacturing method, a through hole 14 is formed on the upper surface 12 and the lower surface 13 of the magnetic layer 11 formed by laminating the two magnetic sheets 20 and 30. The first coil 15 and the second coil 16 electrically connected to each other are formed in a bifilar winding in a horizontal winding direction orthogonal to the thickness of the magnetic layer 11. For this reason, the area ratio of the coil-shaped conductor lines (electrode line segments) on the winding surfaces such as the upper surface 12 and the lower surface 13 can be small, that is, if the winding surfaces have the same size, the number of turns of the coil can be easily increased. Therefore, it is possible to easily increase the number of windings while keeping the size small.
[0031]
Further, since the two magnetic sheets 20 and 30 can use the same conductor line pattern, if they are laminated so that they are aligned with through holes and the back surfaces are attached to each other, the overlapping accuracy of the conductor lines can be improved. Can also be easily raised. For this reason, the coupling coefficient increases, and good noise removal characteristics can be obtained.
Also, in the above-described conductive line forming step, only one kind of pattern is required for the electrode line segments 21 to 24, 31 to 34 and the external electrode connection portions 25, 26, 35, 36 formed on the magnetic sheets 20, 30. Thus, the manufacturing process can be simplified and the manufacturing cost can be reduced.
[0032]
By the way, the above-described choke coil 10 forms the magnetic layer 11 by laminating the two magnetic sheets 20 and 30, but after forming conductive paths on both front and back surfaces of the magnetic layer 11, the through-hole is formed. It may be configured to be electrically connected via the hole 14. In this case, the magnetic layer 11 may be a single magnetic sheet having an appropriate thickness, or a laminate of a plurality of magnetic sheets.
The configuration of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.
[0033]
【The invention's effect】
According to the above-described laminated common mode choke coil of the present invention, the first and second coiled conductor lines are formed in a bifilar winding in the horizontal winding direction, and the ratio of the coiled conductor lines on the winding surface can be small. Therefore, it is possible to easily increase the number of windings while keeping the size small and improve the noise removal characteristics.
Further, since the two coils have high overlapping accuracy of the windings, the coupling coefficient can be increased to improve the noise removal characteristics.
[0034]
In addition, since the area ratio of the electrode on the winding surface is small, the effective area can be increased, and the effect of increasing the common mode impedance can be obtained.
Further, since the capacitance between the windings is reduced, resonance due to the L component and the C component is less likely to occur, and the resonance point can be shifted to the high frequency side, so that the decrease in the coupling coefficient at the high frequency can be reduced. The effect that can be obtained is obtained.
[0035]
Furthermore, according to the method for manufacturing a laminated common mode choke coil of the present invention, in the conductive line forming step, only one type of pattern is used as the electrode line segment and the external electrode connection portion formed on the magnetic layer, so that the manufacturing process can be simplified. Simplification is possible, which makes it easy to manufacture and suitable for low-cost mass production.
That is, according to the multilayer common mode choke coil and the method of manufacturing the same according to the present invention, it is possible to provide a low-cost product having good noise removal characteristics, a simple structure, and easy manufacture.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an embodiment of a laminated common mode choke coil according to the present invention.
FIG. 2 is a perspective view showing a completed state of FIG. 1;
FIG. 3 is an explanatory view showing a method of manufacturing the multilayer common mode choke coil shown in FIG.
[Explanation of symbols]
Reference Signs List 10 common mode choke coil 11 magnetic layer 14 through hole 15 first coiled conductor line (first coil)
16 Second coiled conductor line (second coil)
17 Cover Sheets 18, 19 External Electrodes 20, 30 Magnetic Sheets 21 to 24, 31 to 34 Electrode Lines 25, 26, 35, 36 External Electrode Connections

Claims (3)

First and second coiled conductor lines electrically connected through through holes to upper and lower surfaces of a magnetic layer formed by laminating one or more magnetic sheets are formed on the magnetic layer. A multilayer common mode choke coil characterized by being formed in a bifilar winding in a horizontal winding direction perpendicular to the thickness. The first and second coiled conductor lines are arranged alternately in parallel at the same interval with their ends aligned on one surface, and are connected to through-holes except at positions where the ends are connected to external electrodes. A pair of magnetic sheets or magnetic layers having electrode segments of the same length to be a part are formed by stacking such that the positions of the through holes are aligned and the back surfaces of each other are adhered to each other. The multilayer common mode choke coil according to claim 1, wherein A through-hole forming step of forming a predetermined number of through holes at predetermined positions of a magnetic layer formed by laminating one or more magnetic sheets;
A conductive line forming step of forming first and second coiled conductive lines as electrode line segments and external electrode connection portions on the surface of the magnetic layer;
A pair of the magnetic layers on which the through-holes, the electrode line segments and the external electrode connection portions are formed are prepared, and the through-holes are aligned and laminated so that the back surfaces thereof are attached to each other. A laminated body forming step of laminating a cover sheet made of a magnetic material into a laminated body,
A laminate firing step of integrally firing the laminate,
An external electrode forming step of forming an external electrode conducting to the external electrode connection portion,
A method for manufacturing a laminated common mode choke coil, comprising:

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