JP7042391B2 - Inductor - Google Patents

Description

The present invention relates to an inductor used in various electronic devices.

As the processing speed of microprocessors such as personal computers has increased in recent years, the voltage and current of drive power supplies have been increasing.

In a power supply device such as a DC / DC converter that supplies this drive power supply, the switching frequency is significantly increased for the purpose of downsizing the power supply device, and the power inductor used in these power supply devices has a switching frequency. As the frequency of the high frequency increases, the inductance value thereof is becoming lower.

As a conventional inductor with such a low inductance, a meandering flat conductor is placed in a square columnar magnetic core made of a molded body obtained by pressure-molding magnetic powder whose particle surface is insulated, and the meandering width thereof. It is known that the terminal of the flat conductor is embedded so as to be along the surface direction of the bottom surface of the magnetic core, and the terminal of the flat conductor is pulled out from the side surface of the molded body to form an electrode.

As the prior art document information related to the invention of this application, for example, Patent Document 1 is known.

Japanese Unexamined Patent Publication No. 2004-197218

When miniaturizing a power supply device such as a DC / DC converter having a high switching frequency, the inductor may be required to have a smaller mounting area than the height dimension of the inductor.

This is due to the fact that some of the various electronic components used in power supplies are taller than the inductor.

Then, when trying to reduce the mounting area of the inductor, that is, the area of the bottom surface of the magnetic core, in the above-mentioned conventional inductor, the distance between the widthwise end portion of the meandering portion of the flat conductor and the side surface of the adjacent magnetic core. Has become smaller, and there has been a problem that the magnetic core tends to be saturated when a large current is applied to the inductor.

An object of the present invention is to provide an inductor in which the magnetic core is suppressed from being saturated even if the mounting area is reduced.

In order to solve the above problems, the present invention extends from both a square columnar magnetic core containing a magnetic material, a meandering portion embedded in the magnetic core and a meandering conductor, and both terminal portions of the meandering portion to the opposite side surfaces of the magnetic core. A coil portion having a drawn-out portion and a terminal extending from the drawn-out portion and protruding from the opposite side surface of the magnetic core are provided. It was done.

With the above configuration, since at least both ends of the coil portion in the width direction of the meandering portion are inclined with respect to the bottom surface of the magnetic core, the distance between the widthwise edge portion of the meandering portion and the side surface of the adjacent magnetic core is increased. Therefore, it is possible to suppress the saturation of the magnetic core even if the mounting area of the inductor is reduced.

Perspective view of the inductor according to the embodiment of the present invention. Perspective view through the magnetic core in FIG. Sectional drawing of line AA in FIG. The figure explaining the manufacturing process of the inductor in one Embodiment of this invention. The figure explaining the manufacturing process of the inductor in one Embodiment of this invention. The figure explaining the manufacturing process of the inductor in one Embodiment of this invention. A transmission perspective view showing another example of the inductor in one embodiment of the present invention. Sectional drawing of line BB in FIG. A transmission perspective view showing another example of the inductor in one embodiment of the present invention. Sectional drawing of line CC in FIG. A transmission perspective view showing another example of the inductor in one embodiment of the present invention. Sectional drawing of GG line in FIG.

Hereinafter, the inductor according to the embodiment of the present invention will be described with reference to the drawings.

1 is a perspective view of an inductor according to an embodiment of the present invention, FIG. 2 is a perspective view through which the magnetic core is transmitted in FIG. 1, and FIG. 2 shows the outline of the magnetic core by a broken line. FIG. 3 is a cross-sectional view taken along the line AA in FIG.

As shown in FIGS. 1 and 2, the inductor 11 of the present embodiment has a square columnar magnetic core 12 containing a magnetic material, a meandering portion 14 embedded in the magnetic core 12, and a meandering portion 14 in which the conductor 13 is meandered. A coil portion 17 having a drawing portion 16 extending from both terminal portions 15 of the meandering portion 14 to the facing side surfaces of the magnetic core 12, and a pair of terminals extending from the drawing portion 16 and protruding from the facing side surfaces of the magnetic core 12. Equipped with 18.

Of these, the magnetic core 12 is a compact formed by compression molding a magnetic material granulated by mixing a metallic magnetic material powder and a binder, and is a molded body containing the magnetic material and also functions as an exterior body of the inductor 11. ..

The magnetic core 12 has a bottom surface 19, a top surface 20 located above the bottom surface 19, a first side surface 21 connecting the bottom surface 19 and the top surface 20, and a second side surface opposite the first side surface 21. It has two side surfaces 22, a third side surface 23 connected to the second side surface 22, and a fourth side surface 24 located on the opposite side of the third side surface 23, and has a square columnar shape.

Here, the shape of the magnetic core 12 having a quadrangular prism is not limited to the angle formed by the two adjacent surfaces being limited to 90 °, and may include the angle of the punching taper of the molding die for forming the magnetic core 12. Well, and each of the six surfaces is not limited to a perfect plane, but the corners are used to indicate the directionality of the recesses, protrusions, curved surfaces, and the inductor 11 within the range where the outer shell of the magnetic core 12 does not deviate from the square pillar. It may include a tapered portion that has been shaved.

Next, the coil portion 17 is made of a flat plate-shaped conductor 13, and the thickness of pure copper having a large conductivity is 0.
A flat plate of 2 to 2.0 mm is pressed, and in this embodiment, a copper plate having a thickness of 0.5 mm is used.

The coil portion 17 is stretched in a direction connecting the first side surface 21 and the second side surface 22 of the magnetic core 12, and is meandered from the meandering portion 14 and the end portions 15 in the stretching direction of the meandering portion 14. It has a drawer portion 16 extended to a first side surface 21 and a second side surface 22.

The surface of the coil portion 17 is covered with an insulating layer such as polyurethane or polyamide-imide, if necessary, and is embedded in the magnetic core 12.

Next, the pair of terminals 18 have a drawer portion 16 extended and protrude from the first side surface 21 and the second side surface 22, respectively, from the first side surface 21 to the bottom surface 19 and from the second side surface 22 to the bottom surface 19. It is constructed by being bent toward it.

Then, among the coil portions 17 described above, both terminal portions 15 in the extending direction of the meandering portion 14 are on a straight line along the direction connecting the first side surface 21 and the second side surface 22, which are facing side surfaces on which the terminals 18 project. (Indicated by virtual lines DD in FIG. 2), the coil portions 17 are bent in opposite directions, and the meandering portion 14 of the coil portion 17 has the entire meandering width direction with respect to the bottom surface 19 of the magnetic core 12. It has a slanted configuration.

In the present embodiment configured as described above, as shown in FIG. 3, the meandering width direction dimension (WMH) when the meandering portion 14 is not tilted, and the third side surface 23 and the fourth side surface are present. Even if the dimensions between the meandering portion 14 and the meandering portion 14 are the same, the meandering portion 14 is tilted with respect to the bottom surface 19 of the magnetic core 12, so that the meandering widthwise edge portion 25 of the meandering portion 14 and the adjacent magnetic core 12 The distance from the third side surface 23 and the fourth side surface 24 can be increased.

As described above, when the coil portion 17 is viewed from the stretching direction of the meandering portion 14, the entire width direction of the meandering portion 14 is inclined with respect to the bottom surface 19 of the magnetic core 12, so that the top surface of the magnetic core 12 is inclined. In the plan view seen from 20, the meandering widthwise dimension (WMI) of the meandering portion 14 of the coil portion 17 can be reduced, and the widthwise edge 25 of the meandering portion 14 and the adjacent magnetic core 12th. Since the distance between the three side surfaces 23 and the fourth side surface 24 can be increased, the dimension between the third side surface 23 and the fourth side surface 24 of the magnetic core 12 is reduced in order to reduce the mounting area of the inductor 11. However, it is possible to suppress the saturation of the magnetic core.

In this case, when viewed from the stretching direction of the meandering portion 14, the inclination angle θMB of the meandering portion 14 formed by the bottom surface 19 of the magnetic core 12 and the meandering portion 14 is often 15 ° to 60 °, and is 15 °. If it is smaller than that, the effect of reducing the mounting area of the inductor 11 becomes small, which is not preferable. If it is larger than 60 °, the center of gravity of the inductor 11 becomes high and becomes unstable, which is not preferable. More preferably, it is 30 ° to 45 °.

Next, the manufacturing method of the inductor 11 of the present embodiment described above will be described with reference to FIGS. 4 to 6. 4 to 6 are diagrams illustrating a manufacturing process of an inductor according to an embodiment of the present invention.

First, as shown in FIG. 4, the flat plate-shaped conductor 13 is press-processed to integrally form a coil portion 17 having a meandering portion 14 and a drawing portion 16 and a pair of terminals 18.

The flat conductor 13 is preferably made of a material having a high conductivity, and in the present embodiment, a pure copper copper plate having a thickness of 0.5 mm is used.

The meandering portion 14 is formed in a shape that is stretched while meandering in the stretching direction, and the terminal portions 15 at both ends of the meandering portion 14 are formed in the central portion in the meandering width direction.

The pull-out portion 16 is connected to the terminal portions 15 at both ends in the stretching direction of the meandering portion 14, and is formed in opposite directions in the stretching direction of the meandering portion 14.

The terminal 18 is formed by being connected to the drawer portion 16. It is preferable that the portion forming the terminal 18 is formed larger than the required size, and the through port 26 used for positioning in the subsequent manufacturing process is formed.

Next, as shown in FIG. 5, both terminal portions 15 in the extending direction of the meandering portion 14 are placed on a straight line along the extending direction of the meandering portion 14 (a portion corresponding to the virtual lines DD in FIG. 2). Bend in the opposite direction at the desired angle. The bending angle is set by the angle θMB of the inclination of the meandering portion 14 formed by the bottom surface 19 of the inductor 11 and the meandering portion 14.

As shown in FIG. 4, it is preferable to provide a notch 27 on the valley folding side of the bent portion at the bent portion of both end portions 15 at both ends of the meandering portion 14 in the extending direction, so that the bending is facilitated. preferable. In this case, the positions of the notches 27 of both terminal portions 15 of the meandering portion 14 are not provided on a straight line (the portion corresponding to the virtual lines DD in FIG. 2), but are shifted in consideration of the thickness of the conductor 13. It is possible to prevent the meandering portion 14 from being distorted and the terminals 18 from being misaligned.

Next, as shown in FIG. 6, a magnetic material granulated by mixing a coil portion 17 and a binder made of a metal magnetic material powder and a thermosetting resin is placed in a molding die (not shown). , Compression molding is performed to form the magnetic core 12.

Then, the magnetic core 12 is thermoset by heat-treating the obtained molded product. After that, the terminal 18 may be solder-plated by dipping it in molten solder.

In FIG. 6, the outline of the magnetic core 12 is shown by a broken line.

Finally, the terminal 18 is cut into a predetermined shape, and one terminal 18 is bent from the first side surface 21 to the bottom surface 19, and the other terminal 18 is bent from the second side surface 22 to the bottom surface 19.

By doing so, the inductor 11 shown in FIG. 1 can be obtained.

In the present embodiment described above, the meandering portion 14 is stretched in a direction connecting the opposite side surfaces of the magnetic core 12 having the terminal 18 projected, and both terminal portions 15 of the meandering portion 14 are straight lines in the stretching direction of the meandering portion 14. Although the example of bending in opposite directions has been described above, the meandering portion 14 is not limited to this, and the meandering portion 14 is obliquely crossed in the horizontal direction with the direction connecting the opposite side surfaces of the magnetic core 12 projecting from the terminal 18. It may be stretched in the direction of the meandering.

Another example of such an embodiment of the present invention will be described with reference to the transparent perspective view of FIG. 7 and the cross-sectional view taken along the line BB in FIG. 7 of FIG. In FIG. 7, the outline of the magnetic core 12 is shown by a broken line.

In FIGS. 7 and 8, the same configurations as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The difference in another example of the embodiment of the present invention is that the terminal portions 15 at both ends of the meandering portion 14 in the extending direction connect the first side surface 21 and the second side surface 22 which are facing side surfaces on which the terminal 18 protrudes. On a straight line along the direction (depicted by virtual lines DD in FIG. 7) and a straight line diagonally intersecting in the horizontal direction (depicted by virtual lines FF in FIG. 7), in opposite directions to each other. It was folded.

By doing so, the position where the lead-out portion 16 extends to the first side surface 21 and the second side surface 22 can be adjusted, and the position where the terminal 18 is drawn out can be adjusted. As a result, the terminal 18 can be adjusted. It becomes easy to pull out from the center of the first side surface 21 and the second side surface 22 in the width direction, and the stability when the inductor 11 is mounted on the mounting board (not shown) and the strength of the terminal 18 are improved. Can be done.

In this case, the oblique angle θES formed by the straight line (virtual line DD) along the direction connecting the first side surface 21 and the second side surface 22 and the straight line (virtual line FF) diagonally intersecting in the horizontal direction is determined. It is preferably set to 15 ° to 60 °, and if it is smaller than 15 ° or larger than 60 °, the effect of adjusting the position of the terminal 18 is reduced, which is not preferable. More preferably, it is 20 ° to 40 °.

Further, as another example of the embodiment of the present invention, when viewed from the stretching direction of the meandering portion 14, only the both end portions 29 in the width direction of the meandering portion 14 of the meandering portion 14 are the bottom surface 19 of the magnetic core 12. The one that is inclined with respect to the above is mentioned.

Another example of such an embodiment of the present invention will be described with reference to the transparent perspective view of FIG. 9 and the cross-sectional view taken along the line CC in FIG. 9 of FIG. In FIG. 9, the outline of the magnetic core 12 is shown by a broken line.

In FIGS. 9 and 10, the same configurations as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The difference in another example of the embodiment of the present invention is that when the meandering portion 14 is viewed from the extending direction of the meandering portion 14, the central portion 28 of the meandering portion 14 in the width direction of the meandering portion 14 is located. Both ends 29 of the meandering portion 14 in the width direction are bent in opposite directions, and the both end portions 29 of the meandering portion 14 are arranged with respect to the bottom surface 19 of the meandering portion 12. It is tilted.

By doing so, in addition to the same effect as that of the above-described embodiment of the present invention, the central portion 28 of the meandering portion 14 is arranged along the surface direction of the bottom surface 19 of the magnetic core 12, so that the inductor is used. The height of 11 can be lowered.

It should be noted that the same effect can be obtained when both end portions 29 in the width direction of the meandering portion 14 are bent in the same direction.

Further, as another example of the embodiment of the present invention, there is a case where a plurality of coil portions 17 are embedded in one magnetic core 12.

Another example of such an embodiment of the present invention will be described with reference to the transparent perspective view of FIG. 11 and the sectional view taken along line GG in FIG. 11 of FIG. In FIG. 11, the outline of the magnetic core 12 is shown by a broken line.

In FIGS. 11 and 12, the same configurations as those in the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. The difference in another example of the embodiment of the present invention is that three coil portions 17 are embedded in one magnetic core 12, and the three coil portions 17 have the extending direction of the meandering portion 14. All three coils are arranged in the same direction in the direction connecting the first side surface 21 and the second side surface 22 of the magnetic core 12, and the three coil portions 17 are arranged at the same height in the horizontal direction.

In the example shown in FIGS. 11 and 12, three coil portions 17 of the examples shown in FIGS. 1 to 3 are embedded in the magnetic core 12.

By doing so, the array coil type inductor 11 can be configured, and a plurality of choke coils used in the multi-phase type power supply circuit can be integrated and supported. Since the mounting area per coil portion 17 can be reduced, the inductor is compared with the example shown in FIGS. 1 to 3 in which a plurality of coils having one coil portion 17 embedded in one magnetic core 12 are arranged. The mounting area of 11 can be reduced.

The inductor according to the present invention is industrially useful because it can suppress the saturation of the magnetic core even if the mounting area is reduced.

11 Inductor 12 Magnetic core 13 Conductor 14 Meandering part 15 Terminal part 16 Drawer part 17 Coil part 18 Terminal 19 Bottom surface 20 Top surface 21 First side surface 22 Second side surface 23 Third side surface 24 Fourth side surface 25 Edge part 26 Throughout 27 Notch 28 Central part 29 Both ends

Claims (5)

A coil having a square columnar magnetic core containing a magnetic material, a meandering portion embedded in the magnetic core and a meandering conductor, and a drawing portion extending from both end portions of the meandering portion to opposite side surfaces of the magnetic core. The meandering portion of the coil portion extends between the facing side surfaces and the meandering portion of the coil portion includes a portion and a terminal extending from the drawer portion and projecting from the opposite side surface of the magnetic core. An inductor characterized in that when viewed from the direction connecting both terminal portions, the entire meandering width direction is inclined at an angle of 15 ° or more and 60 ° or less with respect to the bottom surface of the magnetic core. The inductor according to claim 1, wherein both end portions of the meandering portion are bent in opposite directions on a straight line in the extending direction of the meandering portion. The inductor according to claim 2, wherein the meandering portion extends in a direction in which the terminal extends in a direction connecting the protruding side surfaces thereof. The inductor according to claim 2, wherein the meandering portion extends in a direction diagonally intersecting with a direction connecting the facing side surfaces on which the terminals project. The inductor according to claim 1, wherein a plurality of the coil portions are embedded in one magnetic core, and the plurality of coil portions are arranged horizontally with the stretching direction of the meandering portion in the same direction.

Images