JP2017195263A - Coil component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil component using a composite magnetic material, which can obtain high heat dissipation properties even when applied to a power source with high heat generation.SOLUTION: The coil component includes: a magnetic core 20 including a magnetic material and a binder; a coil conductor embedded in the magnetic core 20; and terminal electrodes 41, 42 provided on a mounting surface 23 of the magnetic core 20 and connected to the coil conductor. On the mounting surface 23 of the magnetic core 20, a plurality of projections 24 are provided, and a surface area of the mounting surface 23 is enlarged. In addition, since a space between the projections 24 and the projections 24 serves as a flow path for air, it is also possible to improve the heat radiation performance of the magnetic core 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coil component, and more particularly to a coil component using a composite magnetic material.

  As a power supply coil component, one in which a coil conductor is embedded in a magnetic core made of a composite magnetic material is known (see Patent Document 1). In the coil component described in Patent Document 1, the terminal portion is bent along the bottom surface from the side surface of the magnetic core, so that the heat of the magnetic core whose temperature has risen can be radiated from the terminal portion along the bottom surface. Therefore, it is said that the temperature rise of the magnetic core can be suppressed.

JP 2010-219182 A

  However, the coil component described in Patent Document 1 has a problem in that the heat dissipation of the portion of the bottom surface of the magnetic core that is not covered with the terminal portion is not sufficient. That is, the coil component described in Patent Document 1 has a structure in which the terminal portion is accommodated in the concave portion provided on the bottom surface of the magnetic core, so that an air flow path necessary for heat dissipation is not secured. As a result, there is a problem that heat dissipation becomes insufficient.

  Therefore, an object of the present invention is to improve heat dissipation of a coil component using a composite magnetic material.

  A coil component according to the present invention includes a magnetic core including a magnetic material and a binding material, a coil conductor embedded in the magnetic core, and a terminal electrode provided on a mounting surface of the magnetic core and connected to the coil conductor. A plurality of protrusions are provided on the mounting surface of the magnetic core.

  According to the present invention, since the plurality of protrusions are provided on the mounting surface of the magnetic core, the surface area of the mounting surface is increased. In addition, since the air flow path is formed between the protrusions, the heat dissipation of the magnetic core can be improved. Therefore, the coil component according to the present invention is preferably applied to a coil component for a power source that generates a large amount of heat.

  In the present invention, the terminal electrode includes a first terminal electrode connected to one end of the coil conductor, and a second terminal electrode connected to the other end of the coil conductor, and the plurality of protrusions are The first terminal electrode and the second terminal electrode are preferably disposed between the first terminal electrode and the second terminal electrode. According to this, the space formed between the first terminal electrode and the second terminal electrode can be effectively utilized.

  In the present invention, it is preferable that the height of the protrusion is not more than the height of the terminal electrode. According to this, since it is possible to prevent interference between the protruding portion and the printed board during mounting, mounting reliability is improved.

  In the present invention, the first and second terminal electrodes are arranged in a first direction, and at least two of the plurality of protrusions are arranged in the first direction. It is preferable that a heat dissipation path extending in a second direction orthogonal to the first direction is formed between the two protrusions. According to this, since the heat dissipation path serving as the air flow path is not blocked by the terminal electrode, it is possible to obtain high heat dissipation efficiency.

  In the present invention, it is preferable that the protruding portion has a cross-sectional shape whose area is reduced continuously or stepwise as the distance from the mounting surface increases. According to this, at the time of molding using a mold, there is an advantage that the protruding portion is easily removed from the mold.

  In the present invention, the planar shape of the bottom surface of the protrusion is preferably a circle, an ellipse, or a rectangle with chamfered corners. According to this, since it becomes difficult to produce the damage of a projection part etc., it becomes possible to improve the reliability of a product.

  In the present invention, the magnetic material is preferably made of a metal. According to this, since high magnetic characteristics can be obtained, it is particularly advantageous when used as a coil component for a power supply.

  Thus, according to the present invention, it is possible to improve the heat dissipation of the coil component using the composite magnetic material without adding a special heat dissipation member or the like.

FIG. 1 is a schematic perspective view showing an appearance of a coil component 10 according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view of the coil component 10. FIG. 3 is a schematic perspective view for explaining the shape of the first terminal electrode 41. FIG. 4 is a schematic perspective view for explaining the internal structure of the coil component 10. FIG. 5 is a schematic perspective view showing the appearance of the coil component 10A according to the first modification. FIG. 6 is a schematic perspective view showing the appearance of the coil component 10B according to the second modification. FIG. 7 is a schematic perspective view showing the appearance of the coil component 10C according to the third modification. FIG. 8 is a plan view showing a modification of the planar shape of the protrusion 24. FIG. 9 is a plan view showing a modification of the planar shape of the protrusion 24. FIG. 10 is a plan view showing a modification of the planar shape of the protrusion 24. FIG. 11 is a plan view showing a modification of the cross-sectional shape of the protrusion 24. FIG. 12 is a plan view showing a modification of the cross-sectional shape of the protrusion 24. FIG. 13 is a plan view showing a modification of the cross-sectional shape of the protrusion 24.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing an appearance of a coil component 10 according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view of the coil component 10.

  As shown in FIGS. 1 and 2, the coil component 10 according to the present embodiment includes a magnetic core 20 having a substantially rectangular parallelepiped shape, a coil conductor 30 embedded in the magnetic core 20, and a mounting surface 23 of the magnetic core 20. Two terminal electrodes 41 and 42 connected to the conductor 30 are provided.

  The magnetic core 20 is made of a composite magnetic material including a magnetic material and a binder, and includes a lower magnetic core 21 and an upper magnetic core 22. As the magnetic material contained in the composite magnetic material, it is particularly preferable to use a soft magnetic metal powder having a high magnetic permeability. Specific examples include ferrites such as Ni—Zn, Mn—Zn, and Ni—Cu—Zn, permalloy (Fe—Ni alloy), super permalloy (Fe—Ni—Mo alloy), sendust (Fe—Si—Al). Alloy), Fe—Si alloy, Fe—Co alloy, Fe—Cr alloy, Fe—Cr—Si alloy, Fe, amorphous (Fe-based), nanocrystal (nanocrystal), and the like. In addition, as the binder, thermosetting resin materials such as epoxy resin, phenol resin, silicone resin, diallyl phthalate resin, polyimide resin, and urethane resin can be used.

  The lower magnetic core 21 has a flat plate portion 21 a and a convex portion 21 b, and the coil conductor 30 is placed on the flat plate portion 21 a so that the convex portion 21 b is inserted into the inner diameter portion of the coil conductor 30. The upper magnetic core 22 is a portion in which the coil conductor 30 placed on the lower magnetic core 21 is embedded. Although not particularly limited, in the present embodiment, the convex portion 21b has a tapered shape, and thus, when the lower magnetic core 21 is formed using a mold, the convex portion 21b is formed from the mold. It is easy to come off.

  The coil conductor 30 is a coated conductor in which a core material such as copper is coated with an insulating coating. In the present embodiment, one coil conductor 30 is wound around the convex portion 21b a plurality of times. One end of the coil conductor 30 is connected to the first terminal electrode 41, and the other end of the coil conductor 30 is connected to the second terminal electrode 42.

  As shown in FIG. 3, the first terminal electrode 41 has a mounting portion 43 located on the mounting surface 23 of the magnetic core 20 and a connection portion 44 connected to one end of the coil conductor 30. Passes through the flat plate portion 21 a of the lower magnetic core 21. The second terminal electrode 42 has a similar structure. As shown in FIG. 4, after the coil conductor 30 is placed on the lower magnetic core 21, one end and the other end of the coil conductor 30 are welded to the connection portions 44 of the terminal electrodes 41 and 42, and finally, the upper magnetic core 22. If the coil conductor 30 is embedded by the above, the coil component 10 according to the present embodiment is completed.

  As shown in FIG. 1, a plurality of protrusions 24 are provided on the mounting surface 23 of the magnetic core 20. The protrusion 24 is a part of the lower magnetic core 21, and refers to a rectangular parallelepiped portion that protrudes in the z direction from the reference surface P where the protrusion 24 is not provided, on the mounting surface 23. By providing a plurality of such protrusions 24, the surface area of the mounting surface 23 is increased, so that it is possible to efficiently dissipate the heat generated in the magnetic core 20 by passing a current through the coil conductor 30.

  Here, the height of the protrusion 24, that is, the height in the z direction from the reference plane P is preferably equal to or less than the height of the terminal electrodes 41 and 42 (the thickness of the mounting portion 43 in the z direction). This is because if the protrusion 24 is higher than the terminal electrodes 41 and 42, the protrusion 24 and the printed board may interfere when the coil component 10 is mounted on the printed board. However, if a land pattern having a predetermined thickness exists on the printed circuit board and solder is interposed between the land pattern and the terminal electrodes 41, 42, the projecting portion 24 has the terminal electrode 41. , 42 actually does not cause interference with the printed circuit board. However, considering the mounting reliability, as described above, it is preferable that the height of the protruding portion 24 be equal to or less than the height of the terminal electrodes 41 and 42.

  In the present embodiment, the number of protrusions 24 is six, and all of them are disposed between the first terminal electrode 41 and the second terminal electrode 42. More specifically, there are two rows of three protrusions 24 arranged in the y direction in the z direction. The longitudinal direction of each protrusion 24 is the y direction. As shown in FIG. 1, the y direction is the longitudinal direction of the terminal electrodes 41 and 42, and the x direction is the arrangement direction of the terminal electrodes 41 and 42. With this configuration, even after the coil component 10 is mounted on the printed board, a plurality of heat radiation paths extending in the y direction are formed between the mounting surface 23 of the magnetic core 20 and the printed board. The heat dissipation path is a flow path of air that is a refrigerant. In the present embodiment, three heat dissipation paths are formed.

  Thus, since the coil component 10 according to the present embodiment is provided with the plurality of protrusions 24 on the mounting surface 23 of the magnetic core 20, the surface area is increased, and a plurality of heat dissipation paths after being mounted on the printed circuit board. Is formed. As a result, it is possible to efficiently dissipate the heat generated in the magnetic core 20 by passing a current through the coil conductor 30.

  FIG. 5 is a schematic perspective view showing the appearance of the coil component 10A according to the first modification.

  The coil component 10A according to the first modification has two protrusions 24 and has a structure in which three protrusions 24 arranged in the y direction in FIG. 1 are integrated. Even with such a structure, a plurality of heat dissipation paths extending in the y direction are formed. Although the coil component 10A according to the first modification has a small number of protrusions 24, it is difficult to increase the surface area of the mounting surface 23. However, since the uneven shape of the mounting surface 23 is simpler, the lower magnetic core 21 is formed. It has the advantage of being easy. Thus, in this invention, it is not essential that the projection part 24 is an island shape, and it may be a line shape as shown in FIG.

  FIG. 6 is a schematic perspective view showing the appearance of the coil component 10B according to the second modification.

  The coil component 10B according to the second modified example has seven protrusions 24 and is arranged in a staggered manner. In the case of such a structure, the heat dissipation path is not linear, but there is an advantage that the surface area of the mounting surface 23 is further increased. Thus, in the present invention, it is not essential that the protrusions 24 are arranged in a matrix in the xy direction, and they may be arranged in a staggered manner as shown in FIG.

  FIG. 7 is a schematic perspective view showing the appearance of the coil component 10C according to the third modification.

  The coil component 10 </ b> C according to the third modification has eight protrusions 24, and four protrusions 24 arranged in the y direction exist in two rows in the x direction. Here, the longitudinal direction of each protrusion 24 is the x direction. In the case of such a structure, the width of the heat dissipation path in the x direction is narrower than that of the coil component 10 shown in FIG. 1, but there is an advantage that the surface area of the mounting surface 23 is further increased. As described above, in the present invention, it is not essential that the longitudinal direction of the protrusion 24 coincides with the extending direction of the heat dissipation path. As shown in FIG. It may be orthogonal to the current direction.

  8-10 is a top view which shows the some modification of the planar shape of the projection part 24. As shown in FIG. Here, the planar shape refers to an xy shape viewed from the z direction.

  The planar shape of the protrusion 24 shown in FIG. 8 is a rectangle with chamfered corners. According to such a shape, the protrusion 24 is less likely to be damaged, so that the reliability of the product is improved. Further, if the planar shape is an ellipse like the projection 24 shown in FIG. 9 or the planar shape is a circle like the projection 24 shown in FIG. 10, the projection 24 is less likely to be damaged. .

  FIGS. 11 to 13 are plan views showing some modified examples of the cross-sectional shape of the protrusion 24. Here, the cross-sectional shape refers to a cross-sectional shape orthogonal to the xy plane.

  The cross-sectional shape of the protrusion 24 shown in FIG. 11 is a tapered shape in which the area of the xy cross-section continuously decreases as the distance from the reference plane P increases. According to such a shape, when the lower magnetic core 21 is formed using a mold, there is an advantage that the protruding portion 24 is easily removed from the mold. Further, the cross-sectional shape of the protrusion 24 shown in FIG. 12 is a two-step tapered shape in which the area of the xy cross-section decreases continuously and stepwise as the distance from the reference plane P increases. According to such a shape, in addition to the above effect, an effect that the heat dissipation path is expanded can be obtained. Furthermore, the cross-sectional shape of the protrusion 24 shown in FIG. 13 is a shape in which the taper angle increases as the distance from the reference plane P increases. According to such a shape, the protrusion 24 is more easily removed from the mold.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

10, 10A to 10C Coil component 20 Magnetic core 21 Lower magnetic core 21a Flat plate portion 21b Protruding portion 22 Upper magnetic core 23 Mounting surface 24 Projection portion 30 Coil conductors 41 and 42 Terminal electrode 43 Mounting portion 44 Connection portion P Reference surface

Claims (7)

A magnetic core including a magnetic material and a binder;
A coil conductor embedded in the magnetic core;
A terminal electrode provided on the mounting surface of the magnetic core and connected to the coil conductor;
A coil component, wherein a plurality of protrusions are provided on the mounting surface of the magnetic core. The terminal electrode includes a first terminal electrode connected to one end of the coil conductor, and a second terminal electrode connected to the other end of the coil conductor,
The coil component according to claim 1, wherein the plurality of protrusions are disposed between the first terminal electrode and the second terminal electrode.   The coil component according to claim 2, wherein a height of the protrusion is equal to or less than a height of the terminal electrode. The first and second terminal electrodes are arranged in a first direction;
At least two of the plurality of protrusions are arranged in the first direction, whereby a heat dissipation path extends between the two protrusions in a second direction orthogonal to the first direction. The coil component according to claim 2, wherein the coil component is formed.   5. The coil component according to claim 1, wherein the protruding portion has a cross-sectional shape in which an area is reduced continuously or stepwise as the distance from the mounting surface increases.   6. The coil component according to claim 1, wherein a planar shape of the bottom surface of the protrusion is a circle, an ellipse, or a rectangle with chamfered corners.   The coil component according to any one of claims 1 to 6, wherein the magnetic material is made of metal.

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