JP7251279B2 - coil parts - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coil component, and more particularly to a coil component having a structure in which a lower coil and an upper coil are superimposed on a core having a mounting surface.

Common mode filters are generally used to remove common mode noise superimposed on differential signal lines, and common mode filters are sometimes inserted in power supply lines as well. A common mode filter for a power supply uses a coil wound with a rectangular wire having a large cross-sectional area because the amount of current flowing through the coil is large. For example, Patent Literature 1 discloses a common mode filter for a power supply having a structure in which two coils each formed by winding a rectangular wire are stacked on a core.

International publication WO2015/005129 pamphlet

However, in the coil component described in Patent Document 1, the winding start position and the winding end position of the lower coil are almost the same, whereas the winding start position and the winding end position of the upper coil are different. , resulting in a difference of less than one turn between the number of turns of the lower coil and the upper coil. Since such a difference in the number of turns causes a difference in inductance, there is a problem that the characteristic balance between lines is lost.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to reduce the difference in inductance between a lower coil and an upper coil in a coil component having a structure in which a lower coil and an upper coil are stacked on a core having a mounting surface.

A coil component according to the present invention comprises: a first core having a mounting surface and a coil mounting surface located on the opposite side of the mounting surface; A lower coil having one end drawn out to the first region of the mounting surface and the other end drawn out to the second region of the mounting surface is placed on the lower coil so as to be coaxial with the lower coil, and one end is mounted. An upper coil with the other end drawn out to a third region of the mounting surface and a second core disposed in an inner diameter portion of the lower coil and the upper coil; and the number of turns of one of the upper coils is less than 1 turn than the number of turns of the other of the lower coil and the upper coil, and the diameter of the second core is the portion located at the inner diameter of the one of the lower coil and the upper coil A portion of the inner diameter portion of the other of the lower coil and the upper coil is larger than the diameter of the coil.

According to the present invention, since the diameter of the second core is enlarged at the portion corresponding to the coil with the smaller number of turns, the inductance of the coil with the smaller number of turns is increased. This makes it possible to reduce the difference in inductance between the lower coil and the upper coil due to the difference in the number of turns.

In the present invention, the first and second regions are arranged in a first direction perpendicular to the coil axis, the third and fourth regions are arranged in the first direction, and the first and third regions are arranged in a second direction perpendicular to the coil axis and the first direction, and the second and fourth regions are arranged in the second direction from one end of the lower coil to the other end when viewed from the coil axis direction. and the winding direction from one end to the other end of the upper coil viewed from the coil axial direction may be the same. According to this, it becomes possible to preferably use the coil component according to the present invention as a common mode filter.

In the present invention, the number of turns of the lower coil may be greater than the number of turns of the upper coil by less than one turn. According to this, since the difference in line length between the lower coil and the upper coil caused by the difference in distance from the mounting surface is reduced, it is possible to reduce the difference in DC resistance between the lower coil and the upper coil. .

As described above, according to the present invention, it is possible to reduce the difference in inductance between the lower coil and the upper coil in a coil component having a structure in which the lower coil and the upper coil are stacked on a core having a mounting surface. becomes.

FIG. 1 is a schematic perspective view showing the external structure of a coil component 10 according to a preferred embodiment of the invention. FIG. 2 is a diagram for explaining the internal structure of the coil component 10. As shown in FIG. 3A is a plan view of the lower coil 20, and FIG. 3B is a plan view of the upper coil 30. FIG. FIG. 4 is a partial cross-sectional view of the coil component 10. FIG. FIG. 5 is a partial cross-sectional view of a coil component according to a modification. FIG. 6(a) is a plan view of a lower coil 20 according to a modification, and FIG. 6(b) is a plan view of an upper coil 30 according to a modification.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic perspective view showing the external structure of a coil component 10 according to a preferred embodiment of the invention. FIG. 2 is a diagram for explaining the internal structure of the coil component 10 according to this embodiment.

As shown in FIGS. 1 and 2, the coil component 10 according to the present embodiment includes a plate-shaped core 11 having a mounting surface 11a, and a lower coil 20 and an upper coil 30 arranged on the coil mounting surface 11b of the core 11. a box-shaped core 12 covering the lower coil 20 and the upper coil 30; Note that FIG. 2 shows a state in which the sides (xz plane and yz plane) of the box-shaped core 12 are all omitted so that the lower coil 20 and the upper coil 30 can be seen. In the example shown in FIG. 1 , all of the side surfaces (xz plane and yz plane) are made up of the core 12 , but part or all of them may be made up of the core 11 . Further, the rod-shaped core 13 may be a separate member from the cores 11 and 12 or may be the same member as one of the cores 11 and 12 .

The mounting surface 11a forms an xy plane, and ends 21 and 22 of the lower coil 20 and ends 31 and 32 of the upper coil 30 are arranged in different regions (first to fourth regions) of the mounting surface 11a. ing. The mounting surface 11a is a surface facing the circuit board during mounting, and when the coil component 10 according to the present embodiment is mounted on the circuit board, the land patterns and the ends 21, 22, 31, 32 on the circuit board are aligned with each other. Connected via solder. Here, the ends 21 and 22 are arranged in the y direction, the ends 31 and 32 are arranged in the y direction, the ends 21 and 31 are arranged in the x direction, and the ends 22 and 31 are arranged in the x direction. The portions 32 are arranged in the x direction. In this embodiment, the ends 21 and 31 are provided along the same side extending in the x direction, and the ends 22 and 32 are provided along the same side extending in the x direction. This point is not essential in the invention. For example, the ends 21 and 22 may be arranged along the same side extending in the y direction, and the ends 31 and 32 may be arranged along the same side extending in the y direction.

As shown in FIG. 2, the coil axes of the lower coil 20 and the upper coil 30 are oriented in the z-direction, and the lower coil 20 and the upper coil 30 are stacked in this order on the coil mounting surface 11b so as to be coaxial with each other. ing. In this embodiment, the lower coil 20 and the upper coil 30 are made of rectangular wires, and by bending the respective ends, the four ends 21, 22, 31, 32 are formed in different regions of the mounting surface 11a. are placed.

3A is a plan view of the lower coil 20, and FIG. 3B is a plan view of the upper coil 30. FIG.

As shown in FIG. 3(a), the ends 21 and 22 of the lower coil 20 are bent toward the mounting surface 11a through notches 41 and 42 provided in the core 11. The winding direction toward portion 22 is counterclockwise (counterclockwise) when viewed from the z-direction. Similarly, as shown in FIG. 3B, the ends 31 and 32 of the upper coil 30 are bent toward the mounting surface 11a via notches 43 and 44 provided in the core 11, and the ends The winding direction from 31 to the end 32 is counterclockwise (counterclockwise) when viewed from the z direction. For this reason, for example, when the ends 21 and 31 are used as a pair of input terminals and the ends 22 and 32 are used as a pair of output terminals as a common mode filter, the differential signal line on the input side and the differential signal line on the output side polarities of the differential signal lines are not reversed.

Here, as shown in FIG. 3(a), in the lower coil 20, the winding start position 51 and the winding end position 52 with the end portion 21 as the starting point are substantially the same. As shown, for the upper coil 30, the winding start position 53 and the winding end position 54 with the end 31 as the starting point are shifted by about 0.5 turns. This means that it is difficult to completely match the number of turns of the lower coil 20 and the upper coil 30, resulting in a difference of less than one turn between the two.

For example, when the lower coil 20 is assigned to the side with the number of turns greater than one turn, the inductance of the upper coil 30 becomes smaller than the inductance of the lower coil 20 due to a slight difference in the number of turns. In order to reduce such an inductance difference, in the present embodiment, as shown in FIG. A diameter W2 of a portion located in the inner diameter portion of the upper coil 30 having a smaller number of turns is made larger than W1. As a result, the inductance per turn of the upper coil 30 is larger than that of the lower coil 20, so that the inductance difference caused by the difference in the number of turns can be reduced.

Conversely, if the side with less than one turn is assigned to the upper coil 30, the inductance of the upper coil 30 becomes greater than the inductance of the lower coil 20 due to a slight difference in the number of turns. In this case, as shown in FIG. 5, which is a cross-sectional view, the upper coil 30 with more turns than the diameter W3 of the portion of the rod-shaped core 13 located inside the inner diameter portion of the lower coil 20 with less turns. The diameter W4 of the portion located in the inner diameter portion of is reduced. As a result, since the inductance per turn of the upper coil 30 is smaller than that of the lower coil 20, it is possible to reduce the inductance difference caused by the difference in the number of turns.

Also, by allocating the lower coil 20 to the side where the number of turns is less than one turn, it is possible to reduce the difference in line length between the lower coil 20 and the upper coil 30 . This is because the upper coil 30 has a longer line length than the lower coil 20 because the upper coil 30 is farther from the mounting surface 11a, and the number of turns increases by less than one turn. By assigning the side to the lower coil 20, it is possible to reduce the line length difference.

Furthermore, in the example shown in FIG. 3, the winding start position 51 and the winding end position 52 with the end 21 as the starting point of the lower coil 20 substantially match, and the winding start position with the end 31 as the starting point of the upper coil 30. 53 and the winding end position 54 are shifted by about 0.5 turns, but the relationship between the two may be reversed. That is, as shown in FIG. 6(a), in the lower coil 20, the winding start position 51 and the winding end position 52 starting from the end portion 21 are shifted by about 0.5 turns, whereas the winding end position 52 is shifted by about 0.5 turns. ), for the upper coil 30, the winding start position 53 and the winding end position 54 with the end portion 31 as the starting point may substantially coincide.

In any case, as long as the winding directions of the lower coil 20 and the upper coil 30 are the same and the layout of the ends 21, 22, 31, 32 is such that the polarities are not reversed, the lower coil 20 and the upper coil The number of turns of 30 results in a difference of less than one turn. Therefore, as shown in FIGS. 4 and 5, by increasing the diameter of the core 13 corresponding to the smaller number of turns (reducing the diameter of the core 13 corresponding to the larger number of turns), the difference in inductance is reduced. It becomes possible to

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. Needless to say, it is included within the scope.

10 Coil parts 11-13 Core 11a Mounting surface 11b Coil mounting surface 20 Lower coil 30 Upper coils 21, 22, 31, 32 Ends 41-44 Notches 51, 53 Winding start positions 52, 54 Winding end positions

Claims (3)

a first core having a mounting surface and a coil mounting surface located opposite to the mounting surface;
The coil is arranged on the coil mounting surface so that the coil axis is perpendicular to the coil mounting surface, one end is drawn out to the first region of the mounting surface, and the other end is drawn out to the second region of the mounting surface. a bottom coil;
an upper coil that is superimposed on the lower coil so as to be coaxial with the lower coil, and that has one end drawn out to a third region of the mounting surface and the other end drawn out to a fourth region of the mounting surface; ,
a second core disposed in the inner diameter portion of the lower coil and the upper coil;
the number of turns of one of the lower coil and the upper coil is less than one turn than the number of turns of the other of the lower coil and the upper coil;
The diameter of the second core is larger at the portion located at the inner diameter portion of the other of the lower coil and the upper coil than at the portion located at the inner diameter portion of the one of the lower coil and the upper coil. A coil component characterized by: The first and second regions are arranged in a first direction orthogonal to the coil axis,
the third and fourth regions are arranged in the first direction;
The first and third regions are arranged in a second direction orthogonal to the coil axis and the first direction,
the second and fourth regions are arranged in the second direction;
The winding direction from the one end to the other end of the lower coil viewed from the coil axial direction is the same as the winding direction from the one end to the other end of the upper coil viewed from the coil axial direction. The coil component according to claim 1, characterized by: 3. The coil component according to claim 1, wherein the number of turns of the lower coil is less than one turn than the number of turns of the upper coil.

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