JP2016225479A - Manufacturing method of surface-mounted inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that an external electrode may be brought into contact with an external electrode of a surrounding electronic component or a solder bridge may occur with a neighboring electronic component when a surface-mounted inductor is soldered to a substrate of an electronic apparatus.SOLUTION: A coil is formed which comprises: a wound portion where a lead wire is wound; and a lead-out end portion that is led out of the wound portion, and with which a step is formed in the lead-out end portion. A tablet is formed with which a sealant is previously molded in a shape including a projection for inserting a winding shaft of the coil onto a flat plate and a wall part that is positioned around the projection. The wound portion of the coil is inserted into the projection of the tablet, a distal end portion of the lead-out end portion is disposed on a top face of the wall part, and the coil is accommodated in the tablet. The tablet is disposed within a mold metal die, and the coil is incorporated using the mold metal die. A compact is formed in which a surface of the distal end portion of the lead-out end portion of the coil is exposed and extends on a mounting surface and on the mounting surface of the compact, an external terminal is formed separately from all sides of the mounting surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing a surface-mount inductor that includes a coil formed by winding a conductive wire and a sealing material that includes a resin and a magnetic material, and includes a molded body that incorporates the coil.

  As shown in FIG. 10, a coil 101 is formed by winding a conductive wire on a conventional surface mount inductor, and this coil 101 is embedded in a molded body 102 formed of a sealing material containing magnetic powder and resin. There is one in which the coil 101 is connected to the external terminal 104 on the surface of the molded body 102 (for example, see Patent Document 1). In this surface mount inductor, a coil 101 formed by winding a conductive wire is placed on a tablet, and the leading end 101b of the coil 101 is placed along the outer surface of the columnar protrusion of the tablet, as shown in FIG. The coil and the tablet are placed in the molding die so that the lead-out end portion 101b of the coil 101 is sandwiched between the inner wall surface of the molding die 110 and the outer side surface of the columnar convex portion of the tablet. A molded body 102 containing the coil 101 is formed by this method, and external terminals 104 are formed on the end surface of the molded body and four surfaces adjacent to the end surface.

JP 2010-245473 A

In recent years, along with the further miniaturization of electronic devices such as smartphones and wearable terminals, this type of surface-mount inductor has been mounted with high density.
Under such circumstances, the conventional surface mount inductor has a problem in that the external terminals 104 are formed on the five surfaces of the molded body 102, so that the external terminals formed on the upper surface come into contact with the shield plate. . In order to solve such a problem, external terminals are formed in an L shape (for example, JP 2013-98282 A, JP 2013-98283 A). However, in such a conventional surface mount inductor, since the external terminals are also formed on the end face and side surface of the molded body, the external electrodes formed on the end face and side surfaces are in contact with the external electrodes of the surrounding electronic components. When a surface mount inductor is mounted on an electronic device board and soldered to a circuit pattern, a solder fillet may be formed and a solder bridge may occur between adjacent electronic components, resulting in a short circuit. there were.
Therefore, the conventional surface-mount inductor cannot be used for an electronic device in which electronic components are mounted at a high density.

  An object of the present invention is to provide a method for manufacturing a surface-mount inductor capable of forming a surface-mount inductor that can be mounted with high density in an electronic device.

  The present invention relates to a method of manufacturing a surface-mount inductor formed by using a coil formed by winding a conductive wire and a sealing material including a resin and a magnetic material, and including a molded body incorporating the coil. A coil having a winding portion and a drawing end portion drawn out from the winding portion, having a step formed at the drawing end portion, and a convex member for inserting the coil winding shaft on the flat plate. A pre-molded tablet is formed in a shape provided with a wall portion located around the periphery and the convex portion, the coil winding portion is inserted into the convex portion of the tablet, and the tip end of the drawer end is the upper surface of the wall portion Place the coil in the tablet, place the tablet in the molding die, incorporate the coil using the molding die, and expose and extend the tip end surface of the coil drawing end to the mounting surface Forming the molded body, and on the mounting surface of the molded body, External terminals are formed apart from the side.

  The present invention relates to a method of manufacturing a surface-mount inductor formed by using a coil formed by winding a conductive wire and a sealing material including a resin and a magnetic material, and including a molded body incorporating the coil. A coil having a winding portion and a drawing end portion drawn out from the winding portion, having a step formed at the drawing end portion, and a convex member for inserting the coil winding shaft on the flat plate. A pre-molded tablet is formed in a shape provided with a wall portion located around the periphery and the convex portion, the coil winding portion is inserted into the convex portion of the tablet, and the tip end of the drawer end is the upper surface of the wall portion Place the coil in the tablet, place the tablet in the molding die, incorporate the coil using the molding die, and expose and extend the tip end surface of the coil drawing end to the mounting surface Forming the molded body, and on the mounting surface of the molded body, Since the external terminals spaced is also formed from the side, it is possible to form a surface mount inductor capable of high density mounting in electronic equipment.

It is a perspective view which shows the Example of the surface mount inductor of this invention. It is a perspective view of the coil used in the 1st example of the surface mount inductor of the present invention. It is a perspective view of the tablet used in the 1st example of the surface mount inductor of the present invention. It is a perspective view which shows arrangement | positioning of the coil and tablet of 1st Example of the surface mount inductor of this invention. It is sectional drawing explaining the formation process of the molded object of the 1st Example of the surface mount inductor of this invention. It is a perspective view of the coil used in the 2nd Example of the surface mount inductor of this invention. It is a perspective view of the tablet used in the 2nd example of the surface mount inductor of the present invention. It is a perspective view explaining the formation process of the molded object of the 2nd Example of the surface mount inductor of this invention. It is sectional drawing explaining the formation process of the molded object of the 2nd Example of the surface mount inductor of this invention. It is a perspective view of the conventional surface mount inductor. It is sectional drawing explaining the manufacturing process of the conventional surface mount inductor.

The surface-mount inductor of the present invention includes a coil formed by winding a conductive wire, and a molded body that is formed using a sealing material including a resin and a magnetic material, and that incorporates the coil. The coil includes a winding portion around which the conductive wire is wound and a lead-out end portion drawn out from the winding portion, and a step is formed at the lead-out end portion. The molded body is formed using a tablet that is preformed into a shape in which a sealing material is provided on a flat plate with a convex portion for inserting a winding axis of a coil and a wall portion positioned around the convex portion. In the coil, the winding shaft of the winding part is inserted into the convex part of the tablet, and the leading end part of the drawer end part is disposed on the upper surface of the wall part of the tablet. The tablet in which this coil is stored is placed in a molding die and compressed to form a built-in coil, forming a molded body in which the tip end surface of the coil drawing end is exposed and extended. Is done. External terminals are formed on the mounting surface of the molded body so as to be separated from any side.
Therefore, the surface mount inductor of the present invention has no external terminals other than the bottom surface of the molded body, and the external terminals are not exposed on the surface adjacent to the bottom surface. The solder fillet is not formed when it is in contact with the external electrode of the electronic component or soldered to the circuit pattern of the board of the electronic device.

Hereinafter, an embodiment of a method for manufacturing a surface mount inductor according to the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view showing an embodiment of the surface mount inductor according to the present invention, and FIG. 2 is a perspective view of a coil used in the first embodiment of the surface mount inductor according to the present invention.
1 and 2, 11 is a coil, and 12 is a molded body.
The coil 11 is an air-core coil including a winding part 11a in which a conductive wire is wound in two stages of outer and outer windings so that both ends thereof are positioned on the outer periphery, and a lead-out end part 11b drawn from the winding part 11a. Is formed. The conducting wire is a rectangular wire having a rectangular cross section. The lead-out end portion 11b is pulled out from the same side surface of the winding portion 11a, and once bent to the bottom surface side of the winding portion 11a, the leading end portion is parallel to the bottom surface of the winding portion 11a and away from the winding portion 11a. It is bent so as to extend. Thereby, a level | step difference is formed in the drawer | drawing-out edge part 11b.
The molded body 12 is formed so as to enclose the coil 11 using a sealing material including a resin and a magnetic material. As the sealing material, for example, an iron-based metal magnetic powder is used as a magnetic material, and an epoxy resin is used as a resin, and a mixture thereof is used. On the bottom surface of the molded body 12, the surface of the leading end portion of the lead-out end portion 11b of the coil 11 is exposed. Further, a pair of external terminals 14 are formed on the bottom surface of the molded body 12 so as to cover the surface of the leading end portion of the lead-out end portion 11b of the coil 11 and to be separated from any side of the bottom surface. 11 is connected to the drawer end 11b.

Such a surface mount inductor is formed as follows. First, the coil 11 and the tablet 13 are prepared. As shown in FIG. 2, the coil 11 is a two-step outer conductor with a rectangular insulation coating and a wide surface parallel to the winding axis, with both ends of the conductor positioned on the outer periphery. After winding the outer winding to form the winding part 11a, both ends of the conducting wire are pulled out from the outer periphery of the winding part to form a lead-out end part 11b to form an air-core coil. The conducting wire used in this example used an insulating coating having an imide-modified polyurethane layer. The insulating coating may be polyamide or polyester, and preferably has a high heat resistance temperature. The leading end portion 11b of the coil 11 is pulled out from the same side surface of the winding portion 11a and extends in the opposite direction, and is bent once on the bottom surface side of the winding portion 11a. It is bent so as to be parallel to the bottom surface of the portion 11a. Thereby, a level | step difference is formed in the drawer | drawing-out edge part 11b.
The tablet 13 uses, for example, an iron-based metal magnetic powder as a magnetic material, and an epoxy resin as a resin, and a sealing material obtained by mixing them, as shown in FIG. Are formed by pre-molding into a shape having a bottomed space for housing the coil 11, by providing a convex portion 13 a for inserting a coil and a wall portion 13 b positioned around the convex portion 13 a. At this time, the distance from the inner bottom surface of the tablet 13 to the upper surface of the wall portion 13b is formed larger than the distance from the upper surface of the leading end portion of the leading end portion 11b of the coil 11 to the upper surface of the winding portion 11a.
Next, with the upper surface of the coil 11 down, as shown in FIG. 4, the air core part of the winding part 11a is inserted into the convex part 13a of the tablet 13, and the leading end part of the drawer end part 11b is the wall part. The coil 11 is accommodated in the tablet 13 by arrange | positioning on the upper surface of 13b. At this time, a space is formed between the winding portion 11 a of the coil 11 and the inner bottom surface of the tablet 13.
Subsequently, as shown in FIG. 5A, the tablet 13 in which the coil 11 is accommodated is placed in the molding die 50. In the present embodiment, the molding die 50 has a first upper die 51a, a second upper die 51b, and a lower die 52, and these are combined to form a cavity. Moreover, the tablet 13 is arrange | positioned in a metal mold | die in the state in which the upper surface of the wall part 13b was faced up.
Furthermore, as shown in FIG. 5 (B), the punch P is set in the cavity of the molding die 50 and compressed in a heated state, so that the space of the tablet is filled with the sealing material and the magnetic material The molded body 12 in which the coil 11 is embedded is formed by increasing the density. The surface of the tip end portion of the lead-out end portion 11b of the coil 11 is exposed on the surface of the molded body 12 that is in contact with the punch P. At this time, the leading end portion of the lead-out end portion 11 b of the coil 11 extends in the width direction of the surface with which the punch P of the molded body 12 is in contact with the surface thereof being flush with the surface of the molded body 12. Note that when the tablet 13 in which the coil 11 is housed is placed in the molding die 50, the molding die 50 may be preheated to a temperature higher than the softening temperature of the sealing material.
Next, the obtained molded body 12 is taken out from the molding die 50, and the insulating coating on the surface of the leading end portion of the drawing end portion 11b of the coil 11 exposed on the surface of the molded body 12 is peeled off, and then FIG. As shown in FIG. 3, the external terminal 14 is formed on the surface of the molded body 12 where the leading end portion of the leading end portion 11b of the coil 11 is exposed. The external terminal 14 extends in the width direction of the molded body 12 while covering the surface of the leading end portion of the lead-out end portion 11b of the coil 11, and the width direction of the molded body 12 so that both ends are not exposed to the adjacent surfaces. It is formed shorter than the length of. At this time, the external terminal 14 may be formed by forming a base electrode on the molded body 12 using a conductive material such as silver and plating it with a conductive material containing nickel and tin.
In the molded body 12 formed in this way, the surface on which the external terminals 14 are formed is used as the bottom surface, and this surface is mounted on a substrate of an electronic device, and the external terminals 14 are soldered to wiring such as the substrate. .

FIG. 6 is a perspective view of a coil used in the second embodiment of the surface mount inductor of the present invention, and FIG. 7 is a perspective view of a tablet used in the second embodiment of the surface mount inductor of the present invention.
The coil 61 includes a winding portion 61a obtained by winding a conducting wire having a flat rectangular insulating coating and a wide surface perpendicular to the winding axis, and a pair of leading ends drawn from the winding portion 61a. An air-core coil having 61b is formed. The pair of drawer end portions 61b are drawn out from the winding portion 61a so as to extend in parallel to each other in a direction perpendicular to the winding axis, and once bent to the bottom surface side of the winding portion 61a, the tip end portion is wound. It is bent so as to be parallel to the bottom surface of the portion 61a. As a result, a step is formed at the drawer end 61b.
As shown in FIG. 7, the tablet 63 uses a sealing material in which a resin and a magnetic material are mixed, and a convex portion 63a for inserting a coil winding shaft on a flat plate and a wall positioned around the convex portion 63a. A portion 63b is provided, and is formed by preforming into a shape having a bottomed space for housing the coil 61. At this time, the wall portion 63b is formed so as to have a portion 63b1 that is partially high, and the distance from the inner bottom surface of the tablet 63 to the top surface of the high portion 63b1 is such that the leading end portion 61b of the coil 61 It is formed to be the same as the distance from the upper surface of the tip portion to the upper surface of the winding portion 61a.
As shown in FIG. 8 (A), the coil 61 is inserted with the air core portion of the winding portion 61a into the convex portion 63a of the tablet 63 and the tip end portion of the lead-out end portion 61b on the wall with the upper surface facing down. By being arranged on the upper surface of the high portion 63b1, the tablet 63 is accommodated. At this time, the winding portion 61a of the coil 61 and the inner bottom surface of the tablet 63 are in contact with each other. The same material as the tablet 63 is used for the opening surface of the tablet 63, and as shown in FIG. 8B, a plate-like tablet formed in a size capable of covering a portion other than the high wall portion 63b1. 65 is arranged. At this time, the thickness of the plate-like tablet 65 is formed larger than the distance between the upper surface of the lower part of the wall 63b of the tablet 63 and the upper surface of the higher part 63b1 of the wall.
As shown in FIG. 9 (A), the tablets 63 and 65 in which the coils 61 are housed are the first upper mold 91a, the second upper mold 91b, It has the type | mold 52, It arrange | positions in the molding die 90 in which a cavity is formed by combining these.
The punch P is set in the cavity of the molding die 90 and compressed in a heated state so that the tablet 63 and the tablet 65 are integrated, the space of the tablet is filled with a sealing material, and the density of the magnetic material is increased. Thus, a molded body 62 including the coil 61 is formed. As shown in FIG. 9B, the surface of the tip end portion of the lead-out end portion 61b of the coil 61 is exposed on the surface of the molded body 62 that is in contact with the punch P. At this time, the leading end portion of the lead-out end portion 61 b of the coil 61 extends in the width direction of the surface with which the punch P of the molded body 62 is in contact with the surface thereof being flush with the surface of the molded body 62. Note that when the tablets 63 and 65 in which the coil 61 is housed are placed in the molding die 90, the molding die 90 may be preheated to a temperature higher than the softening temperature of the sealing material.
The molded body 62 obtained in this way is taken out from the molding die 90, and the insulating coating on the surface of the leading end portion of the lead-out end portion 61b of the coil 61 exposed on the surface of the molded body 62 is peeled off, and then FIG. ), The external terminal 64 is formed on the surface of the formed body 62 where the leading end of the leading end 61b of the coil 61 is exposed. The external terminal 64 extends in the width direction of the molded body 62 while covering the surface of the leading end portion of the lead-out end portion 61b of the coil 61, and the width direction of the molded body 62 so that both ends are not exposed to the adjacent surfaces. It is formed shorter than the length of. At this time, the external terminal 64 is preferably formed by forming a base electrode on the molded body 62 using a conductive material such as silver and plating it with a conductive material containing nickel and tin.
In such a molded body 62, the surface on which the external terminals 64 are formed is used as a bottom surface, and this surface is mounted on a substrate of an electronic device or the like, and the external terminals 64 are soldered to wiring such as the substrate.

As mentioned above, although the Example of the manufacturing method of the surface mount inductor of this invention was described, this invention is not limited to this Example. For example, in the examples, iron-based metal magnetic powder was used as the sealing material as the sealing material, and epoxy resin was used as the resin, but the metal magnetic powder of another composition was used as the magnetic material, and its surface was coated with an insulator such as glass. Metal magnetic powder or metal magnetic powder with a modified surface may be used. Further, as the resin, a thermosetting resin such as a polyimide resin or a phenol resin, or a thermoplastic resin such as a polyethylene resin or a polyamide resin may be used. Moreover, although the case where the rectangular wire used as a conducting wire which comprises a coil was shown was shown, the thing of various shapes, such as circular, a rectangle, and a polygon, can be used for a cross section.
Furthermore, in the first embodiment, a tablet formed in a plate shape with the same material as the tablet is mounted on the opening surface of the tablet so that the tip end of the coil drawing end is exposed, and heated with a molding die. The molded body in which the coil is embedded may be formed by compression. Further, in the first embodiment, the coil was embedded by filling a powdery sealing material made of the same material as the tablet from the opening surface of the tablet, and heating and compressing it with a molding die. A molded body may be formed.
Furthermore, in the second embodiment, instead of a plate-shaped tablet, a powdery sealing material made of the same material as the tablet is filled, and this is heated and compressed with a molding die to produce a coil. A molded body in which is embedded may be formed.

11 Coil 12 Molded body

Claims (6)

In a method of manufacturing a surface-mount inductor formed by using a coil formed by winding a conductive wire and a sealing material containing a resin and a magnetic material, and including a molded body incorporating the coil,
A winding portion wound with a conducting wire, and a drawing end portion drawn out from the winding portion, forming a coil in which a step is formed in the drawing end portion;
Forming a tablet preformed into a shape in which a convex portion for inserting the winding axis of the coil on the flat plate and a wall portion located around the convex portion are provided on the flat plate;
Inserting the winding portion of the coil into the convex portion of the tablet, placing the leading end of the drawer end on the upper surface of the wall portion, and storing the coil in the tablet,
The tablet is placed in a molding die, the coil is built using the molding die, and a molded body is formed in which the surface of the leading end of the leading end of the coil is exposed and extended on the mounting surface,
A method for manufacturing a surface-mount inductor, wherein an external terminal is formed apart from any side on the mounting surface of the molded body. The tablet is formed with a portion having a different height on the wall portion, the leading end portion of the drawing end portion of the coil is disposed on the high portion of the wall portion, and the coil is housed therein.
A plate-like tablet formed by preforming the sealing material separately from the tablet is disposed on the tablet in which the coil is stored so that the tip of the leading end of the coil is exposed. The method for manufacturing a surface mount inductor according to claim 1, wherein the coil is built in using a molding die, and a molded body is formed in which a tip end surface of a leading end portion of the coil is exposed and extended on the mounting surface. The tablet is formed with a portion having a different height on the wall portion, the leading end portion of the drawing end portion of the coil is disposed on the high portion of the wall portion, and the coil is housed therein.
The tablet containing the coil is filled with the sealing material powdered so that the leading end of the drawing end of the coil is exposed, and the coil is built in using the molding die. The method of manufacturing a surface-mount inductor according to claim 1, wherein a formed body is formed in which a tip end surface of a lead-out end portion of the coil is exposed and extended on a mounting surface.   4. The method for manufacturing a surface mount inductor according to claim 1, wherein the coil is formed by winding so that both ends of the conducting wire are positioned on an outer periphery of the winding portion.   The method for manufacturing a surface mount inductor according to claim 1, wherein the conducting wire is a rectangular wire.   The coil includes a rectangular wire as the conducting wire, and the rectangular wire is wound so that a wide surface thereof is perpendicular to a winding axis of the coil to form a winding portion. Item 4. A method for manufacturing a surface-mount inductor according to Item 3.

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