JP2019117823A - Inductor and method of manufacturing the same - Google Patents

Abstract

To provide an inductor with high magnetic efficiency in which a decrease in magnetic efficiency is suppressed even if it is an inductor using a flat plate-like conductor drawn linearly and a method of manufacturing the same.SOLUTION: The inductor includes: a conductor unit 10 made of a metal plate 11 and drawn linearly; an exterior body 20 made of a magnetic material and covering the conductor unit 10; and an external electrode 30 connected to the conductor unit 10 and exposed from the exterior body 20. The conductor unit 10 is bent in a width direction in a bellows manner.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an inductor used in various electronic devices and a method of manufacturing the same.

  2. Description of the Related Art Conventionally, inductors have been widely used in electronic devices such as DC-DC converter devices for the purpose of boosting and lowering power supply voltage, smoothing of direct current, and the like.

  And in recent years, the switching frequency in the drive circuit of a DC-DC converter has shifted to the high frequency side, and the inductance value of the inductor has become small by the high frequency of the switching frequency.

  As such an inductor having a low inductance value, it is provided on the core member, on the inside of the core member, on a flat plate-like conductor extending linearly, and on the outer surface of the core member, and electrically connected to the conductor In addition to this, there is known an inductor provided with a terminal electrode electrically connected to a mounting substrate to be mounted.

WO 2006/070544

  As described above, in the configuration of the conventional inductor, since the conductor provided inside the core member is a flat conductor, when the conductor is flat, the magnetic path length of the magnetic flux circulating around the conductor is long As a result, the magnetic efficiency tends to decrease.

  The present invention solves the above-mentioned conventional problems, and provides an inductor with good magnetic efficiency and a method of manufacturing the same in which the decrease in magnetic efficiency is suppressed even in the case of an inductor using a linearly drawn conductor The purpose is

  In order to achieve the above object, according to one aspect of the present invention, a conductor portion made of a metal plate and drawn linearly, an exterior body made of a magnetic material and covering the conductor portion, and a conductor portion are connected and exposed from the exterior body The conductor portion is bent in a bellows-like manner in the width direction.

  Further, another aspect of the present invention includes a conductor portion made of a metal plate and drawn in a straight line, an exterior body made of a magnetic material and covering the conductor portion, and an external electrode connected to the conductor portion and exposed from the exterior body. In the method of manufacturing the inductor, the step of forming the conductor portion includes a metal plate preparing step of preparing a metal plate drawn in a straight line shape, and a bending conductor portion forming step of bending the metal plate in a transverse direction into a bellows. It is possessed.

  According to one aspect of the present invention, since the conductor portion is bent in the width direction in a bellows manner, an effect of being able to improve the magnetic efficiency of the inductor can be obtained.

Further, according to another aspect of the present invention, the step of forming the conductor portion includes a metal plate preparing step of preparing a linearly-extending metal plate, and formation of a bent conductor portion which folds the metal plate in a transverse direction into a bellows. Since the process is included, the effect of being able to improve the magnetic efficiency of the inductor can be obtained.

A perspective view of an inductor according to an embodiment of the present invention Transparent perspective view of an inductor according to an embodiment of the present invention Sectional view along the line AA in FIG. 1 Sectional view of line B-B in FIG. 1 The figure which illustrates the manufacturing process of the inductor in one execution form of this invention The figure which illustrates the manufacturing process of the inductor in one execution form of this invention The figure which illustrates the manufacturing process of the inductor in one execution form of this invention The figure which illustrates the manufacturing process of the inductor in one execution form of this invention Sectional drawing which shows another example of the inductor in one embodiment of this invention The perspective view of the metal plate which shows the other another example of the inductor in one embodiment of this invention A transparent perspective view showing another example of the inductor in the embodiment of the present invention

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

  FIG. 1 is a perspective view of an inductor according to an embodiment of the present invention, FIG. 2 is a transparent perspective view of the same inductor, FIG. 3 is a cross-sectional view taken along line AA in FIG. It is a sectional view of the BB line.

  In addition, FIG. 2 is a transparent perspective view which permeate | transmitted the exterior body 20 mentioned later, and has shown the outline of the exterior body 20 with the broken line.

  As shown in FIGS. 1 to 4, the inductor 100 according to the present embodiment includes a conductor portion 10 made of a metal plate and linearly extended, an exterior body 20 made of a magnetic material and covering the conductor portion 10, and a conductor portion An external electrode 30 connected to the electrode 10 and exposed from the package 20 is provided.

  Here, in the present specification, as shown in FIG. 1, the direction in which the conductor portion 10 linearly extends is defined as a first direction 201, the tip direction of the arrow is the back side, and the side opposite to the tip of the arrow is It may be called the front side.

  Further, a direction perpendicular to the first direction 201 and along the width direction of the conductor portion 10 and the external electrode 30 is defined as a second direction 202, the tip direction of the arrow is the back side, and the side opposite to the tip of the arrow is the front side It may be called.

  Then, a direction perpendicular to the first direction 201 and the second direction 202 is defined as a third direction 203, the tip direction of the arrow may be referred to as the upper side, and the side opposite to the tip of the arrow may be referred to as the lower side.

  The first, second and third directions are the same in the drawings after FIG.

  Of the inductor 100 according to the present embodiment, the outer package 20 is made of a magnetic material in which magnetic powder and a binder are mixed, and the magnetic material is converted to granular powder and the conductor portion 10 is formed into granulated powder. It is embedded and pressure-molded.

  As described above, the exterior body 20 covers the conductor portion 10, and serves as the magnetic core of the closed magnetic path of the inductor 100 and the exterior body 20 serving as the main body of the inductor 100.

  Among the magnetic substance powder and the binder constituting the package 20, the magnetic substance powder is a soft magnetic material which is a metal magnetic substance mainly composed of iron or iron having a high saturation magnetic flux density, such as iron-nickel based alloy, iron- Metal magnetic materials of crystalline composition such as silicon-based alloy, iron-silicon-aluminum-based alloy, iron-silicon-chromium-based alloy, and amorphous composition such as iron-silicon-boron-based alloy are crushed or atomized And so on.

  The binder coats the particles of the magnetic powder and intervenes between the particles to bind the particles together and to insulate that the eddy current flows between the particles, thereby suppressing the eddy current loss of the outer package 20 from increasing. It is

  The bonding material is preferably made of an insulating thermosetting resin such as epoxy resin or silicone resin, mixed with the metal magnetic powder to insulate the particles, and bonded by heat treatment after pressure molding. It is preferable because the material can be thermally cured to bond the particles.

  And this exterior body 20 is the first side which connected the bottom 21 and the top 22 in the first direction 201 near side in the bottom 21 below the 3rd direction 203, the top 22 opposite to the bottom 21, and the 1st direction 201 side. 23, a second side 24 opposite to the first side 23, a third side 25 connecting the first side 23 and the second side 24 on the far side of the second direction 202, and an opposite of the third side 25 It has the fourth side 26 connecting the first side 23 and the second side 24 on the side, and in the present embodiment, the outer dimension of the exterior body 20 is approximately four of 4.0 mm × 4.0 mm × 2.6 mm. It has a prismatic shape.

  The external electrode 30 is connected to the conductor portion 10 embedded inside the exterior body 20, exposed from the first side surface 23 and the second side surface 24 of the exterior body 20 to the outside of the exterior body 20, and an external circuit Used for connection with (not shown).

  The external electrode 30 is made of a metal plate 11 such as a copper material, and in the present embodiment, a copper plate having a thickness of 0.15 mm and a width dimension of 2.4 mm is provided along the second direction 202 in the width direction. It is exposed to the outside of the exterior body 20 in a direction, and is bent along the first side 23 and the bottom 21 and the second side 24 to the bottom 21 so as to be processed into a surface mount type external electrode 30.

  The conductor portion 10 is formed of a metal plate 11 such as a copper material drawn linearly, and in the present embodiment, a copper plate having a thickness of 0.15 mm and a width dimension of 2.4 mm in the first direction 201 direction. It is drawn linearly at a length of 2.0 mm.

  Then, the conductor portion 10 is bent in a bellows manner in the width direction (second direction 202).

  Here, to fold in a serpentine fold in the width direction means that a mountain fold and a valley fold, or a valley fold and a mountain fold are alternately repeated in the width direction of the conductor portion 10, as shown in FIG. It means being bent so as to be zigzag in the direction.

  In the example shown in FIGS. 1 to 4, the conductor portion 10 is equally divided into four equal parts each having a width of 2.4 mm and a width of 0.6 mm, and the conductor portion 10 is bent into a bellows. In a length of 2.0 mm.

  The inductor 100 of this embodiment is configured as described above.

According to the inductor 100 of the present embodiment described above, the conductor portion 10 is bent in the width direction in a bellows-like manner by the above configuration, so that the metal plate 11 forming the conductor portion 10 has a flat plate shape. The magnetic path length of the magnetic flux circulating around the conductor portion 10 can be shortened, and the effect of improving the magnetic efficiency can be obtained.

  The fact that the magnetic path length can be shortened will be described in more detail. Assuming that the shortest magnetic path length is the size of the outer periphery of the conductor portion 10, the conductor portion of the conductor portion 10 is a flat plate-like metal plate 11 like the conventional inductor and the conductor portion 10 like the inductor 100 of this embodiment. The metal plate 11 is compared in the width direction to be folded in a bellows manner.

  In the case of the conventional inductor, since the width dimension of the metal plate 11 is 2.4 mm and the thickness dimension is 0.15 mm, the dimensions of the outer periphery of the conductor portion are twice the width dimension 2.4 mm and the thickness dimension 0.15 mm It becomes 5.1 mm of the dimension which added the double.

  On the other hand, in the conductor portion 10 of the present embodiment, the width dimension of the metal plate 11 is divided into four equally divided by 0.6 mm and the thickness dimension of the four metal plates 11 (0.15 mm) In the inductor 100 of the present embodiment, the outer peripheral dimension of the conductor portion 10, ie, the shortest magnetic path length, is 2.4 mm as compared with the conventional inductor. It can be shortened from 1 mm to 2.4 mm.

  Since the permeability of the inductor is in inverse proportion to the magnetic path length, as the magnetic path length becomes shorter, the permeability becomes larger, the magnetic efficiency of the inductor 100 can be improved, and further, the inductor 100 can be miniaturized. It is something that can be done.

  In the present embodiment, as shown in FIGS. 2 and 3, in the conductor portion 10, the metal plate 11 of the conductor portion 10 is preferably stacked in the width direction of the conductor portion 10. Lamination in the width direction of the conductor portion 10 means that the metal plates 11 adjacent to each other are bent until they are bent in a bellows-like manner and come into contact with each other.

  Thereby, the magnetic path length can be further shortened, and the magnetic efficiency of the inductor 100 can be further improved.

  In this case, it is preferable to have an insulating layer (not shown) on at least the laminated surface 12 of the conductor portion 10.

  The laminated surface 12 means the surface of the metal plate 11 in contact.

  In addition, this insulating layer is a technique such as transfer of insulating resin such as polyurethane resin, polyester resin, enamel resin, or polyamideimide resin to a portion to be the laminated surface 12 with a desired thickness of 5 to 50 μm. It is applied, heat treated and cured.

  Thus, even if the metal plates 11 adjacent to each other are bent in a bellows-folded manner and are adjacent to each other, they are insulated by the insulating layer, so that the effect of the skin effect is suppressed even if the current supplied to the inductor 100 is a high frequency current. You can get the effect of being able to

  The insulating layer may be interposed at least on the laminated surface 12, but may have an insulating layer so as to cover the entire conductor portion 10.

  Further, in the present embodiment, the conductor portion 10 and the external electrode 30 can be integrally formed via the connecting portion 40.

  The connecting portion 40 is a single metal plate 11 in which the conductor portion 10, the connecting portion 40 connected on both sides of the conductor portion 10, and the external electrode 30 connected to the connecting portion 40 are integrally formed. is there.

  The connecting portion 40 plastically deforms between the conductor portion 10 and the external electrode 30 and connects the conductor portion 10 and the external electrode 30 by bending the conductor portion 10 in a bellows manner.

  Thereby, the connection between the conductor portion 10 and the external electrode 30 can be omitted, and there is no fear that the welded portion may come off, as compared with the case where the conductor portion 10 and the external electrode 30 are connected by welding or the like. The effect of improving the connection reliability between the portion 10 and the external electrode 30 can be obtained.

  In this case, the connecting portion 40 has the first main surface 41 on the upper side in the third direction 203 and the second main surface 42 on the back side of the first main surface 41 on the lower side of the third direction 203 It is preferable to have the recessed part 43 extended along the width direction of the conductor part 10 in any one of 41 and the 2nd main surface 42, or both the 1st main surface 41 and the 2nd main surface 42. As shown in FIG.

  When the conductive portion 10 is bent in a bellows manner, the convex portion extended along the width direction of the conductive portion 10 provided on the holding mold for holding the metal plate 11 is an external electrode of the connecting portion 40. It is possible when the edge portion on the 30 side is pressed until it bites.

  As a result, when the conductor portion 10 is bent in a bellows manner, the plastic deformation of the connecting portion 40 can be suppressed from reaching the external electrode 30, and the deterioration of the flatness of the external electrode 30 can be suppressed. It is possible to obtain the effect hardening that the loss of the connection reliability between the external electrode 30 and the external circuit can be suppressed.

  The depth dimension of the concave portion 43 is not particularly limited, but a depth of about 5 to 20 μm is preferable, and if it is smaller than 5 μm, the holding power to hold the metal plate 11 is weak. If it is large, the influence of the reduction in the cross-sectional area of the metal plate 11 becomes large, which is not preferable. More preferably, it is 10 to 15 μm.

  Next, a method of manufacturing the above-described inductor 100 according to the present embodiment will be described with reference to FIGS.

  First, a conductor portion forming process for forming the conductor portion 10 will be described.

  The conductor portion forming step includes a metal plate preparing step of preparing the metal plate 11 drawn in a straight line, and a bent conductor portion forming step of bending the metal plate 11 in the widthwise direction into bellows.

  Among them, in the metal plate preparing step, as shown in FIG. 5, the metal plate 11 drawn in a straight line is prepared.

  In this case, the metal plate 11 is a copper plate having a thickness of 0.15 m and a width dimension of 2.4 mm in advance to the conductor portion 10, the connecting portion 40 connected to both sides of the conductor portion 10, and It is preferable to add the dimensions of the external electrodes 30 to be connected together, and it is preferable to prepare the metal plate 11 in which the conductor portion 10, the connecting portion 40 and the external electrode 30 are integrated.

  Here, in FIG. 5, when viewed from the upper side in the third direction 203, a virtual line of a bending line when the conductor portion 10 is bent in a bellows manner is shown in an intermediate portion in the extending direction of the metal plate 11. A folding line 13 indicated by a one-dot chain line is a mountain fold line, and a bending line 14 indicated by a two-dot chain line indicates a valley folding line.

  As described above, the fold lines 13 and 14 are alternately arranged with the mountain fold line and the valley fold line along the straight extending direction of the metal plate 11.

  Next, in the bending conductor portion forming step, as shown in FIG. 6, the bending line 13 is folded in a mountain fold and the folding line 14 is folded in a valley fold along the bending lines 13 and 14 by pressing. The plate 11 is bent in a bellows-like manner along the extending direction.

  In this case, as the internal angle of the bent adjacent metal plates 11 decreases from 180 °, the distance between the mountain fold and the valley fold gradually narrows when viewed from the upper side of the third direction 203.

  For this reason, it is preferable to divide an inside angle into multiple times like 150 degrees, 120 degrees, and 90 degrees, for example, and to bend so that an inside angle of metal plates 11 comrades which adjoins may become small gradually.

  In the example shown in FIG. 6, the example of the state in which the internal angle of the bent adjacent metal plate 11 comrades was bend | folded to 90 degrees is shown.

  Next, in the conductor portion forming step, it is preferable to perform the conductor portion compressing step after the bending conductor portion forming step.

  In the conductor portion compression step, as shown in FIG. 7, the conductor portion 10 is compressed in the width direction of the conductor portion 10 from both sides in the width direction (second direction 202) of the conductor portion 10 using the compression die 50 Thus, the metal plates 11 adjacent to each other in the width direction of the conductor portion 10 are stacked.

  In this case, it is preferable to perform the insulating layer forming step between the metal plate preparing step and the bending conductor portion forming step.

  In the insulating layer forming step, an insulating layer (not shown) is formed on at least the laminated surface 12 of the conductor portion 10 on which the metal plate 11 is laminated. For example, polyurethane resin, polyester resin, enamel resin, or polyamide An insulating resin such as an imide resin is applied at a desired thickness of 5 to 50 μm to a portion to be the laminated surface 12 using a technique such as transfer, and is heat treated to be cured.

  The insulating layer may be formed on the whole of the conductor portion 10.

  Here, in the case where the conductor portion 10, the connecting portion 40, and the external electrode 30 described above are integrally formed of the metal plate 11, the connecting portion 40 has the first main surface 41 above the third direction 203, and the third direction 203. The second main surface 42 is provided on the back side of the first main surface 41 at the lower side.

  Then, in the conductor forming step and the conductor compressing step in the conductor forming step, the edge portions of the connecting portion 40 on the external electrode 30 side are held from both sides of the first main surface 41 and the second main surface 42. It is preferable to bend the conductor portion 10 in a bellows manner in a state of being held and held by a mold (not shown).

  Furthermore, on the holding surface of the holding mold of either the first main surface 41 side or the second main surface 42 side, or both the first main surface 41 side and the second main surface 42 side, It is more preferable to provide the convex part (not shown) extended to the width direction, and to hold | maintain the convex part by the force biting in the connection part 40. As shown in FIG.

  Thereby, when bending the conductor part 10 in a bellows fold, it can suppress that the plastic deformation of the connection part 40 extends to the external electrode 30. FIG.

  Next, an exterior body forming step is performed.

  In the package forming step, as shown in FIG. 8, in the cavity 60 of a molding die for molding the package 20, a magnetic material in which a magnetic powder and a binder are mixed, a conductor portion 10 and a connecting portion 40 Then, the outer electrode 30 is protruded out of the cavity 60, the magnetic material is pressed, and then the binder is cured to obtain the outer package 20.

  Finally, as required, the surface of the external electrode 30 is plated with solder, the external electrode is cut to a desired length, or the external electrode 30 is bent, as shown in FIG. The inductor 100 shown in 2 can be obtained.

  According to the method of manufacturing the inductor of the present embodiment described above, the same effects as the effects described in the inductor 100 of the present embodiment described above can be obtained by the above-described manufacturing method.

  In the present embodiment, an example is described in which the conductor portion 10 is folded in the width direction into a bellows and stacked, but as shown in FIG. 9 showing another example of the inductor of the present embodiment, The conductor portion 10 may be bent in a bellows-like manner in the width direction.

  In the example shown in FIG. 9, the conductor portion 10 shown in FIG. 6 is covered with the exterior body 20, and the cross section orthogonal to the direction in which the conductor portion 10 is drawn in a straight line is seen as in the cross section of FIG. Therefore, the same function and effect as those of the above-described embodiment can be obtained.

  Further, in the present embodiment, the width dimension of the metal plate 11 of the conductor portion 10 and the width dimension of the metal plate 11 of the external electrode 30 are the same, and the cross sectional areas of the conductor portion 10 and the external electrode 30 are the same. In the cross section perpendicular to the extending direction of the conductor portion 10, the cross-sectional area of the conductor portion 10 may be larger than the cross-sectional area of the external electrode 30.

  Another example of such an inductor according to the present embodiment is shown in FIGS.

  As shown in FIG. 10, in the metal plate preparation step, a metal plate is prepared in which the width dimension of the portion forming the conductor portion 10 is larger than the width dimension of the portion forming the connecting portion 40 and the external electrode 30.

  And as shown in FIG. 11, the conductor part is formed by arranging the valley-folded bending line 14 also in the part which is larger than the connecting part 40 of the conductor part 10 and the width dimension of the external electrode 30 and bending it into a bellows. The cross-sectional area of the conductor portion 10 is larger than the cross-sectional area of the external electrode 30 in a cross section orthogonal to the extending direction of 10.

  Also in the inductor shown in FIGS. 10 and 11 and the method of manufacturing the same, the same effects as those of the inductor 100 of the present embodiment and the method of manufacturing the same described above can be obtained. By increasing the size, it is possible to obtain the effect that the direct current resistance of the conductor portion 10 is reduced and the loss as an inductor can be reduced.

  INDUSTRIAL APPLICABILITY The configuration of the inductor according to the present invention and the method for manufacturing the same can be an inductor with good magnetic efficiency even if it is an inductor using a linearly drawn conductor, and is industrially useful.

DESCRIPTION OF SYMBOLS 10 conductor part 11 metal plate 12 lamination surface 13 bending line 14 bending line 20 exterior body 21 bottom surface 22 top surface 23 1st side 24 2nd side 25 3rd side 26 4th side 30 external electrode 40 connection part 41 1st main surface 42 second main surface 43 recess 50 compression mold 60 cavity 100 inductor 201 first direction 202 second direction 203 third direction

Claims (12)

A conductor portion formed of a metal plate and extended linearly, an exterior body made of a magnetic material and covering the conductor portion, and an external electrode connected to the conductor portion and exposed from the exterior body, the conductor portion in the width direction An inductor characterized in that it is bent in a serpentine manner. The inductor according to claim 1, wherein the metal plate of the conductor portion is stacked in the width direction of the conductor portion. 3. The inductor according to claim 2, further comprising an insulating layer on at least a lamination surface of the conductor portion. The inductor according to claim 1, wherein the conductor portion and the external electrode are integrally formed via a connecting portion. The connecting portion has a first main surface and a second main surface on the back side of the first main surface, and either one of the first main surface and the second main surface or the first main surface and the first main surface 5. The inductor according to claim 4, further comprising a recess extending along the width direction of the conductor portion on both of the two main surfaces. The inductor according to claim 1, wherein a cross-sectional area of the conductor portion is larger than a cross-sectional area of the outer electrode in a cross section orthogonal to the extending direction of the conductor portion. A method of manufacturing an inductor comprising: a conductor portion made of a metal plate and drawn in a straight line; an exterior body made of a magnetic material and covering the conductor portion; and an external electrode connected to the conductor portion and exposed from the exterior body. The step of forming the conductor portion includes a metal plate preparing step of preparing a linearly extending metal plate, and a bending conductor portion forming step of bending the metal plate in a widthwise direction into a serpentine fold. Method of manufacturing an inductor. The conductor portion forming step has a conductor portion compressing step of laminating the metal plates of the conductor portion in the width direction by compressing the conductor portion in the width direction after the bent conductor portion forming step. The method of manufacturing an inductor according to claim 7. 9. The method according to claim 8, further comprising an insulating layer forming step of forming an insulating layer on at least a lamination surface of the conductor portion between the metal plate preparing step and the bent conductor portion forming step. The metal plate preparing step prepares the metal plate having a length integrally forming a connecting portion connected to both sides of the conductor portion and the extending direction of the conductor portion and an external electrode connected to the connecting portion. A method of manufacturing an inductor according to claim 7, characterized in that: The connecting portion has a first main surface and a second main surface on the back side of the first main surface, and in the bending conductor portion forming step, the connecting portion is formed on both sides of the first main surface and the second main surface. The conductor portion is bent in a bellows-like manner in a state of being sandwiched and held by a mold, and either one of the first main surface side and the second main surface side, or the first main surface side and the first main surface side A convex portion extending in the width direction of the conductor portion is provided on the holding surface of both the molds on the second main surface side, and the convex portion is engaged with and held by the connecting portion. 10. The manufacturing method of the inductor according to 10. The method according to claim 7, wherein in the metal plate preparing step, a width dimension of a portion forming the conductor portion is larger than a width dimension of a portion forming the connection portion and the external electrode portion. .