JPH1032129A - Thin coil part and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient thin coil part on which the connection space of the inner end part for a coil pattern can be narrowed, the magnetic coupling between a coil pattern and a core can be improved, the area of the coil pattern can be increased, and to provide the manufacturing method of the device. SOLUTION: A laminated coil is formed of a laminate of a plurality of sheets of insulating material, having conductive coil patterns 2 and 3 on one surface or both surfaces. A magnetic core insulating through-hole 7 is provided in the center part of the laminated coil. A recessed part 11 is provided on the inner wall of the through-hole 7. A conductor 12, with which the inner end parts of the coil patterns 2 and 3, located between different layers, are fixed to the inner wall of the recessed part 11. The recessed part 11 and the conductor 12 are formed by providing a through-hole on the laminated coil, and after the conductor 12 has been fixed to the inner wall of the through-hole 7, the through-hole 7 is provided so that a part of the through-hole is scraped off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin coil component configured as a transformer or a choke coil used in an electronic device or a power supply device and a method of manufacturing the same, and more particularly to a device used in a converter circuit for a switching power supply.

[0002]

2. Description of the Related Art With the recent miniaturization of switching power supplies, power supply transformers and choke coils are also required to be thinner and have higher frequencies. In order to meet such a demand, as shown in FIG. 9A, a laminated coil a is formed by laminating printed wiring-provided insulating materials, a terminal c is provided on the laminated coil a, and the laminated coil a is provided. Various laminated coil components configured by assembling a magnetic core b with a have been used in place of coil components using a winding wire.

[0003] This type of laminated coil is formed by laminating an insulating layer of a required thickness between coil patterns and connecting the terminals of each coil pattern to form a winding.
Such a laminated coil component has a high current density and is easy to be thin, and particularly when used as a transformer,
It is known that a transformer having a high degree of magnetic coupling between primary and secondary can be obtained by increasing the number of layers.

The ends of each coil pattern in the laminated coil a are generally connected by through-hole plating on the inner and outer peripheral sides of the pattern. Conventional means of connecting coil pattern terminals on the inner circumference side of the pattern include:
There are the following two types.

[0005] The first type of connecting means is shown in FIG.
(C) and FIG. 10 and FIG.
As shown in (B) and (C), a primary coil pattern 2 (or a secondary coil pattern 3) is formed on both sides of an insulating material 1 made of an insulating sheet or an insulating plate, and these coil patterns 2 or 3 are formed. A conductor 5 is fixed to the inner wall of the through hole 4 by plating, and a conductor pattern 5 is fixed to the inner wall of the through hole 4 by plating.
Two or three or three inner ends are connected to each other. Reference numeral 6 denotes a pad formed on the front and back edges of the insulating material 1.

[0008] The coil pattern 2 or 3 formed on the front and back surfaces of the insulating material 1 as described above is regarded as one coil unit. As shown in a perspective view of FIG. An insulating material 8 made of an insulating sheet or an insulating plate is interposed between the coil units, and is integrally bonded and laminated, for example, via an adhesive provided on the insulating material 8, and laminated.
Thereafter, a through hole 7 for inserting the magnetic core b is opened, and a through hole 15 for passing the terminal c is formed in the pad 6.
Are provided, and the through holes 15 corresponding to the laminating direction are plated and connected. In this case, the through hole 4 at the inner end of the coil pattern becomes an interstitial via hole after connection of the coil unit. An example of this first type of connection means is described in Japanese Patent Application Laid-Open No. 6-21592.

The second type of connecting means is described in FIG. 11. In the example of FIG. 11, a coil unit is not formed, and a primary coil pattern 2 and a secondary coil pattern 3 are formed, respectively. Alternately laminated and adhered insulating material 1
Thereafter, through-holes 10 are provided on the inner and outer peripheral sides of the coil patterns 2 and 3 and a conductor is plated on the inner walls thereof, so that the inner ends of the pair of primary coil patterns 2 and 2 are The inner end portions of the side coil patterns 3 and 3 are connected to each other, and a through hole 15 is provided in the pad 6 on the outer peripheral side to provide a connection portion for the terminal c. An example of the second connection means is disclosed in Japanese Patent Application Laid-Open No. Hei 7-99123.

[0008]

According to the prior art shown in FIGS. 9 and 10, the distance between the inner ends of the coil patterns 2 and 2 or between the inner ends of the coils 3 and 3 on the front and back surfaces of the insulating material 1 is reduced. After the coil units are formed by connecting the through holes 4 with the conductors 5 provided by plating, the coil units are laminated with the insulating material 8 interposed therebetween, and the through holes 15 are formed at the outer ends of the coil patterns 2 or 3. Therefore, it is necessary to perform plating twice, so that connection by plating is required twice.

Further, when used as a transformer, the magnetic coupling improves as the number of opposing surfaces of the primary coil pattern 2 and the secondary coil pattern 3 increases.
Since each of the secondary coils is constituted by two coil patterns 2, 2 or 3, each sandwiching the insulating material 1, the primary coil units and the secondary coil units are alternately stacked. However, there is a problem that the primary coil pattern 2 and the secondary coil pattern 3 have few surfaces facing each other, and the magnetic coupling of the transformer is weakened.

On the other hand, according to the prior art shown in FIG.
After laminating the insulating material 1 on which the coil patterns 2 and 3 are formed, the inner and outer ends of the coil patterns 2 and 3 can be simultaneously connected by through-hole plating, and only one plating connection is required. There is an advantage, and the lamination position of the coil patterns 2 and 3 can be freely selected, and the primary coil pattern 2 and the secondary coil pattern 3 can be alternately laminated, so that magnetic coupling can be strengthened. There is an advantage.

However, according to the configuration of FIG. 11, as shown in FIG. 1C, a space for connecting the pattern indicated by a hatched portion E is required inside each of the coil patterns 2 and 3, and As the pattern width decreases due to the decrease in space, the length of the patterns 2 and 3 increases,
As a result, there arises a problem of coil heating due to an increase in DC resistance.

Also, since the distance from the leg of the core inserted into the through hole 7 to the coil pattern is long, the coil and the core b
The degree of coupling with the primary coil and the secondary coil is large, and the magnetic coupling is not improved despite the large number of opposing surfaces of the primary coil and the secondary coil.

In view of the above-mentioned problems, the present invention can reduce the connection space between the inner ends of the coil pattern, thereby improving the magnetic coupling between the coil pattern and the core, and reducing the area of the coil pattern. It is an object of the present invention to provide an efficient thin coil component that can be made larger and a method for manufacturing the same.

[0014]

In order to achieve this object, a thin coil component according to the present invention comprises a laminated coil formed by laminating a plurality of insulating materials provided with a conductor coil pattern on one or both surfaces, In a thin coil component in which terminals of coil patterns of each layer are connected by a conductor provided through a laminated coil and a through hole for inserting a magnetic core is provided at the center of the laminated coil, a concave portion is formed on an inner wall of the through hole. And a conductor connecting the inner ends of the coil patterns between different layers is fixed to the inner wall of the recess (claim 1).

In the present invention, when the coil component constitutes a transformer, a structure in which a primary coil pattern and a secondary coil pattern are alternately laminated (claim 2).
Or a structure in which the coil pattern is formed in a rectangular shape, and the concave portion of the through hole is provided in a portion corresponding to a corner portion inside the coil pattern (Claim 3), or an insulating material provided with the coil pattern Is formed in a rectangular shape, and the outer periphery of the outermost coil pattern is formed along the vicinity of the outer periphery of the insulating base material, so that the outer periphery of the coil pattern is formed wider than other coil pattern portions. A structure in which an insulating material is provided between the leg of the magnetic core inserted into the hole and the conductor and the inner end of the coil provided in the concave portion, or the unevenness of the leg of the magnetic core inserted into the through hole. And a gap is formed between the conductor provided in the concave portion and the leg portion by contacting the convex portion with a conductor-free surface other than the concave portion to which the conductor for connecting the inner end portion of the coil pattern is fixed ( Claim 6) is adopted.

Further, in the method of manufacturing a thin coil component according to the present invention, an insulating material having a conductor coil pattern provided on one or both sides is laminated to produce a laminated coil, and the laminated coil is connected to each other in the laminated coil. A through-hole penetrating the inner end of the coil pattern set connected to the conductor, a conductor connecting between the inner ends is fixed to the inner wall of the through-hole, and the through-hole is provided inside the coil pattern of the laminated coil. A through hole for inserting a leg of the magnetic core is provided so that a part of the hole is deleted (claim 7).

[0017]

According to the first aspect, the inner ends of the coil patterns are connected to each other by a conductor fixed to a concave portion provided in the inner wall of the through hole for inserting the core, instead of a conductor having a through hole having a circular cross section as in the prior art. Therefore, the inner peripheral side of the coil pattern can be provided closer to the through hole (core) as compared with the case of the through hole, and the connection space between the inner ends of the coil pattern becomes narrower, and the coil The width of the pattern can be widened, the electric resistance can be reduced, and the magnetic coupling can be improved.

In the second aspect, the primary coil pattern and the secondary coil pattern are alternately arranged, so that the magnetic coupling is further improved.

In the third aspect, the coil pattern is formed in a rectangular shape, and the recess of the through hole is provided in a portion corresponding to a corner inside the coil pattern, so that the space of the corner is effective as a connection space. And the connection space can be further narrowed.

In the fourth aspect, the outer peripheral side of the coil pattern is formed wider than the other coil pattern portions, so that the electric resistance can be further reduced and the magnetic coupling is strengthened.

According to a fifth aspect of the present invention, an insulating material is provided between the leg of the magnetic core inserted into the through hole, the conductor provided in the concave portion, and the inner end of the coil, thereby providing insulation between the core and the concave conductor. Is secured.

According to the present invention, electrical insulation from the recessed conductor is ensured by the unevenness provided on the leg portion of the magnetic core inserted into the through hole, and an insulating material is not required.

In the manufacturing method according to the seventh aspect, the concave portion is formed at the same time as the formation of the through hole, so that another step for forming the concave portion becomes unnecessary.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view showing an example of a printed coil of the present invention, and FIG. 1B is a partially enlarged view thereof.
1A and 1B, reference numeral 7 denotes the magnetic core b.
Are usually formed by combining two E-shaped cores or a combined structure of an E-shaped core and an I-shaped core. Is inserted into. Reference numeral 11 denotes a concave portion provided on the inner wall of the through hole 7, and reference numeral 12 denotes a conductor provided on the inner wall of the concave portion 11. Each of the conductors 12 connects the inner ends of the coil patterns of different layers of the laminated coil. . These recesses 11 and conductors 12 are provided in the same number as the number of sets of coil patterns to be connected.

FIGS. 2 to 5 are views showing the steps of manufacturing the thin coil component of this embodiment. FIG. 2A is a plan view of the laminated body, and FIG. 2B is a cross-sectional view thereof. In this example, the primary coil patterns 2A to 2D and the pads 6,
60 respectively, and the secondary side coil pattern 3
The four insulating materials 1 for which A to 3D are manufactured are integrally bonded and laminated via an insulating material 8 having an adhesive.

Next, a plan view of FIG.
As shown in the cross-sectional view of FIG.
A and 2B, two sets of 2C and 2D, and through-holes 11A for connecting the respective inner ends of the two sets of secondary coil patterns 3A and 3B, 3C and 3D, to the inner ends of each coil pattern And the pad 6
Then, a through hole 15 is opened.

Next, as shown in the sectional view of FIG. 4A, a conductor 12 is fixed to the inner walls of the through holes 11A and 15 by plating. Thereby, the coil pattern 2
The inner ends of A and 2B, 2C and 2D, 3A and 3B, and 3C and 3D are electrically connected to each other.

Next, as shown in the cross-sectional views of FIG. 4B and FIG. 5, the through-hole 7 is formed so as to lack a part of the arc of the cross-section of each through-hole 11A. As shown in FIG. 5, the leg b1 of the magnetic core b is inserted into the through hole 7. In this case, in order to electrically insulate the conductor patterns on the front and back surfaces of the laminated coil and the magnetic core b, an insulating material 16 is provided in a portion facing the magnetic core b around the opening of the through hole 7.

As described above, by providing the conductor 12 for connecting the inner end of the coil pattern to the concave portion 11 provided on the inner wall of the through hole 7, as can be seen from the comparison between FIGS. The connection space E between the inner ends of the coil patterns can be reduced as compared with the case of using the conventional through holes 5, and the inner peripheral sides of the coil patterns 2 and 3 are formed through the through holes 7.
That is, it can be provided close to the core leg b1, and the magnetic coupling is improved. Further, since the inner peripheral sides of the coil patterns 2 and 3 can be provided close to the through holes 7, the lengths and widths of the coil patterns 2 and 3 can be shortened and the electric resistance can be reduced. Becomes possible.
In the case of configuring a transformer, the primary coil pattern 2 and the secondary coil pattern 3 can be alternately arranged, so that magnetic coupling is further improved.

FIG. 6A is a plan view showing another embodiment of the present invention, in which the shape of the coil pattern 2 or 3 is square, and the concave portion 11 of the through hole 7 is formed inside the coil pattern 2 or 3. It is provided in a portion corresponding to a corner portion. According to the present embodiment, the space at the corners of the coil patterns 2 and 3 is effectively used as a connection space, and the connection space can be further narrowed. Therefore, the effects of reducing the electric resistance and strengthening the magnetic coupling are obtained. Will be encouraged.

FIG. 6B is a plan view showing another embodiment of the present invention. The insulating material 1 provided with the coil patterns 2 and 3 has a rectangular shape, and the width of the coil patterns 2 and 3 is not uniform. The outer circumference a of the outermost coil pattern is formed along the vicinity of the outer circumference of the insulating material 1 so as to be wider than other coil pattern portions. According to the present embodiment, the effect of reducing the electrical resistance of the coil patterns 2 and 3 can be more favorably achieved than in the above-described embodiment, and the magnetic coupling with the core b on the outer peripheral side of the coil patterns 2 and 3 becomes stronger. In terms of magnetic coupling, an effect superior to that of the above embodiment can be obtained.

FIG. 7A is a plan view showing another embodiment of the present invention. In this embodiment, the shape of the concave portion 11 is not a semicircular shape but an arcuate shape. The diameter of the through hole is made larger than that of the above-described embodiment, and the diameter of the through hole 7 is increased.
Can be realized by changing the cut position. According to this embodiment, a large area can be obtained as the conductor 12.

FIG. 7 (B) shows the formation of through holes for the outer pads 6 as well as the inner conductors 12.
The conductor 17 which is continuous over the entire width in the stacking direction is formed by plating and cutting the conductor 17. According to the present embodiment, there is no need to provide a terminal, and a surface-mounted thin coil component can be obtained.

When a conductive material is used as the magnetic core b, insulation may be required between the magnetic core b and the coil patterns 2 and 3 and the conductor 12. In this case, an insulating material is applied to the outer peripheral portion of the leg portion b1, or FIG.
As shown in the embodiments (A) and (B), an insulating material 13 is provided between the leg b1 of the magnetic core b inserted into the through hole 7 and the conductor 12 provided in the recess 11 and the inner end of the coil. By providing, insulation between the core b and the concave conductor 12 and the coil patterns 2 and 3 is ensured.

FIGS. 8C and 8D show an example in which the shape of the leg b1 of the core b is devised to insulate the core b from the coil patterns 2, 3 and the conductor 12. Irregularities are provided on the legs b1 of the magnetic core b inserted into the through holes 7, and the convex portions 18 are formed on the conductor non-formed surfaces other than the concave portions 11 to which the inner end connecting conductors 12 of the coil patterns 2, 3 are fixed. The conductor 12 and the leg b1 which are provided in the recess 11 in contact with each other.
And a gap G is formed between them to electrically insulate the core b and the conductor 12. This embodiment has an advantage that the insulating material 13 is not required.

In the above embodiment, the example in which the coil patterns 2 and 3 are formed on both surfaces of the insulating material 1 has been described.
One of the coil patterns 2 and 3 may be formed on one surface of each insulating material 1.

[0037]

According to the first aspect of the present invention, a recess is formed in the inner wall of the through hole for inserting the magnetic core, and the conductor for connecting the inner end of the coil pattern is provided in the recess. The connection space between the inner ends of the provided coil patterns is narrowed, the width of the coil patterns can be widened accordingly, the electric resistance can be reduced, and the magnetic coupling is also good. As a result, an efficient thin coil component can be provided.

According to the second aspect, when the thin coil component constitutes a transformer, the primary side coil pattern and the secondary side coil pattern are alternately arranged to further improve magnetic coupling. .

According to the third aspect, the coil pattern is formed in a square shape, and the concave portion of the through hole is provided in a portion corresponding to the inner corner portion of the coil pattern, so that the space of the corner portion serves as a connection space. It can be used effectively and the connection space can be narrowed,
The effect of reducing the electric resistance and strengthening the magnetic coupling can be better achieved.

According to the fourth aspect, since the outer peripheral side of the coil pattern is formed wider than the other coil pattern portions, the electric resistance can be further reduced, and the magnetic coupling with the core on the outer peripheral side of the coil pattern can be achieved. Also become stronger.

According to the fifth aspect, an insulating material is provided between the leg of the magnetic core inserted into the through hole, the conductor provided in the recess, and the inner end of the coil. Insulation is ensured.

According to the sixth aspect, the electrical insulation from the concave conductor is ensured by the unevenness provided on the leg of the magnetic core inserted into the through hole, and the insulating material is not required.

According to the manufacturing method of the seventh aspect, the concave portion is formed simultaneously with the formation of the through-hole, so that another step for forming the concave portion becomes unnecessary.

[Brief description of the drawings]

FIG. 1A is a plan view showing an example of a print coil of the present invention, FIG. 1B is a partially enlarged view thereof, and FIG. 1C is a plan view of a conventional print coil.

2A is a plan view showing a state before through-hole processing in the laminated print coil of FIG. 1A, and FIG. 2B is a cross-sectional view showing a laminated state of FIG.

3A is a plan view showing a state after through-hole processing in the laminated print coil of FIG. 1A, and FIG. 3B is a cross-sectional view showing the laminated state of FIG.

FIG. 4A is a partial cross-sectional view showing a state where a conductor is processed in a through hole provided in the laminated print coil of FIG. 3;
(B) is a partial cross-sectional view showing a state in which a through hole is further formed.

FIG. 5 is a cross-sectional view showing the entire laminated print coil of FIG. 4 (B).

FIGS. 6A and 6B are plan views each showing another example of the printed coil of the present invention.

FIGS. 7A and 7B are plan views each showing another example of the printed coil of the present invention.

8A is a plan view showing another example of the print coil of the present invention, FIG. 8B is a partially enlarged view thereof, FIG. 8C is a plan view showing another example of the print coil of the present invention, FIG. D) is a partially enlarged view thereof.

FIG. 9A is a perspective view showing a conventional thin coil component,
(B) is an exploded perspective view showing an example of the coil unit,
(C) is a sectional view of the coil unit.

FIG. 10 is an exploded perspective view showing an example of a conventional thin coil component.

FIG. 11 is an exploded perspective view showing another example of a conventional thin coil component.

[Description of Signs] 1: Insulating material, 2, 2A to 2D: Primary side coil pattern,
3, 3A to 3D: secondary coil pattern, 6, 6A: pad, 7: through hole, 8: insulating material, 11: recess, 11A:
Through hole, 12: conductor, 13: insulating material, 15: through hole

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Haruyoshi Noda 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation

Claims (7)

[Claims] 1. A laminated coil is formed by laminating a plurality of insulating materials provided with a coil pattern of a conductor on one or both sides, and the terminals of the coil patterns of each layer are connected by a conductor provided through the laminated coil. In the thin coil component having a through hole for inserting a magnetic core at the center of the laminated coil, a concave portion is provided on an inner wall of the through hole, and an inner end portion of a coil pattern between different layers is provided on an inner wall of the concave portion. A thin coil component in which a conductor connecting the components is fixed. 2. The thin coil component according to claim 1, wherein the coil component constitutes a transformer, and a primary coil pattern and a secondary coil pattern are alternately laminated. 3. The coil pattern according to claim 1, wherein the coil pattern is formed in a rectangular shape, and a concave portion provided in an inner wall of the through hole is provided in a portion corresponding to an inner corner of the coil pattern. Thin coil parts. 4. An insulating material provided with a coil pattern according to claim 1, wherein the outer periphery of the outermost coil pattern is formed along the vicinity of the outer periphery of the insulating base material. A thin coil component formed wider than other coil pattern portions. 5. The thin coil component according to claim 1, wherein an insulating material is provided between a leg portion of the magnetic core inserted into the through hole and a conductor provided in the concave portion. . 6. The magnetic core according to claim 1, wherein the legs of the magnetic core to be inserted into the through holes are provided with irregularities, and the convex portions are other than the concave portions to which the conductors for connecting the inner ends of the coil pattern are fixed. A thin coil component, wherein a gap is formed between a conductor provided in the recess and brought into contact with a conductor-free surface, and the leg. 7. A laminated coil is produced by laminating insulating materials provided with a coil pattern of a conductor on one or both sides, and connected to each other in the laminated coil on the inner peripheral side of the coil pattern of the laminated coil. A through hole penetrating an inner end of the coil pattern set; a conductor connecting the inner ends is fixed to an inner wall of the through hole; a part of the through hole is provided inside a coil pattern of the laminated coil; A method of manufacturing a thin coil component, comprising: providing a through hole for inserting a leg of a magnetic core so as to eliminate the above.