JP2013110184A - Surface-mounted inductor manufacturing method and surface-mounted inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a surface-mounted inductor whose size is reduced and moldability is enhanced.SOLUTION: A surface-mounted inductor manufacturing method according to the present invention uses a coil obtained by winding a conductor, whose cross section has a rectangular shape, a sealant containing a resin and magnetic material powder, and a guide member molded using a resin or ceramics into a flat plate shape where columnar protrusion parts are formed in peripheral edge parts of the flat plate shape. The coil is mounted on the guide member and is loaded into a molding die while setting both end parts of the coil to extend along outer side surfaces of the columnar protrusion parts of the guide member. A molded body is obtained by sealing the coil and the guide member with a sealant using a resin molding method or a powder compaction molding method under a state where both end parts of the coil are sandwiched between the outer side surfaces of the columnar protrusion parts of the guide member and an inner wall surface of the molding die. Both end parts of the coil are at least partially exposed to a surface of the molded body and external electrodes connected to exposed parts of both end parts of the coil are provided for the surface or an outer periphery of the molded body.

Description

  The present invention relates to a method for manufacturing a small surface-mount inductor.

  2. Description of the Related Art Surface mount inductors that enclose a coil around which a wire is wound in a core are widely used. With recent downsizing and thinning of electronic devices such as mobile phones, electronic components such as surface mount inductors are also required to be downsized and low profiled. Therefore, the applicant applied in Patent Document 1 previously filed, a small surface mounting using a coil and a pre-formed tablet in which a flat wire is wound around an outer and outer winding so that both ends thereof are drawn to the outer periphery. An inductor and its manufacturing method were proposed.

  In the method of manufacturing a surface-mount inductor disclosed in Patent Document 1, a tablet is first prepared by pre-molding a sealing material including a resin and a filler into a shape having columnar protrusions on a peripheral edge of a flat plate shape. Next, a coil having a rectangular cross section is wound to produce a coil, and the coil is placed on the tablet. At this time, both ends of the coil are arranged along the columnar convex portion of the tablet, and both ends of the coil are sandwiched between the outer side surface of the columnar convex portion of the tablet and the inner wall surface of the molding die. The tablet is placed in a molding die, and a preforming sealing material is loaded into the molding die. Next, the coil and the sealing material are integrated using a resin molding method or a powder molding method with both ends of the coil sandwiched between the outer side surface of the columnar convex portion of the tablet and the inner wall surface of the molding die. To obtain a molded body. Finally, an external electrode connected to a portion where at least a part of both ends of the coil is exposed on the surface of the molded body is provided on the surface or outer periphery of the molded body to obtain a surface mount inductor.

JP 2010-245473 A

  As described above, in the method of Patent Document 1, a sealing material including a resin and a filler is preliminarily molded into a tablet having a shape having columnar protrusions on a flat peripheral edge. However, when the size is 2 mm square or less, the tablet size is also reduced, and in particular, the columnar convex portions are thinned. Therefore, in a tablet made of a sealing material containing a resin and a filler (particularly, the content of the filler is 60 Vol% or more), it is sufficient to preform it in a complicated shape having a columnar protrusion. It becomes difficult to ensure mechanical strength. When the mechanical strength of the tablet is reduced, a part of the tablet is easily lost or damaged when it is transported or loaded into a molding die. If a part of the tablet is missing or damaged, the internal coil may be misaligned or molded, which may result in poor inductor characteristics or variations.

  Therefore, an object of the present invention is to provide a method for manufacturing a surface-mount inductor that is smaller and has high moldability.

  In order to solve the above-described problems, a method for manufacturing a surface-mount inductor according to the present invention includes a coil in which a conducting wire having a flat cross section is wound, a sealing material including a resin and magnetic powder, and a flat peripheral edge. And a guide member formed of resin or ceramics in a shape having a columnar convex portion at the part. The coil is placed on the guide member, and both ends of the coil are loaded into the molding die along the outer side surface of the columnar convex portion of the guide member. Sealing material for coil and guide member using resin molding method or powder molding method with both ends of coil sandwiched between outer side surface of columnar convex part of guide member and inner wall surface of molding die To obtain a molded body. An external electrode connected to a portion where at least a part of both ends of the coil is exposed on the surface of the molded body is provided on the surface or outer periphery of the molded body.

  According to the method for manufacturing a surface mount inductor of the present invention, a small surface mount inductor can be easily obtained. Then, at least a part of both end portions of the coil can be buried and fixed at a predetermined position of the molded body. Furthermore, since the flat surfaces of both end portions can be exposed on the surface of the molded body, a good bonding area with the external electrode can be obtained.

  In the method for manufacturing a surface mount inductor according to the present invention, a guide member formed of resin or ceramics in a shape having a columnar convex portion on a flat peripheral edge portion is used. Resin or ceramics has high moldability, and even if it is small, it can be easily processed into a complicated shape having columnar protrusions, and sufficient mechanical strength can be secured. Therefore, it is not necessary to produce a tablet having a complicated shape with a sealing material including a resin and a filler, and the sealing material may be a simple shape such as a plate shape, a column shape, or a powder shape.

  Since the end portion of the coil is not sandwiched between the molding dies, it is not necessary to provide an end drawing portion of the coil, and the molding die can be made inexpensive with a simple structure.

It is a perspective view of the air-core coil used by this invention. It is a perspective view of the guide member used in the 1st example of the present invention. It is a perspective view explaining the arrangement | positioning relationship of the air-core coil of 1st Example of this invention, a guide member, and a sealing material (tablet). It is a figure explaining the manufacturing method of the surface mount inductor of 1st Example of this invention, (a) is a top view, (b) is AB sectional drawing of (a). It is a figure explaining the manufacturing method of the surface mount inductor of the 1st Example of this invention. 1 is a perspective view of a surface-mount inductor according to a first embodiment of the present invention. It is a perspective view of the guide member used in the 2nd example of the present invention. It is a perspective view explaining the arrangement | positioning relationship of the air-core coil of 2nd Example of this invention, a guide member, and a sealing material (tablet). It is a figure explaining the manufacturing method of the surface mount inductor of the 2nd Example of this invention, (a) is a top view, (b) is AB sectional drawing of (a). It is a perspective view of the surface mount inductor of the 2nd example of the present invention. It is a perspective view of the air-core coil used in the 3rd example of the present invention. It is a perspective view of the guide member used in the 3rd example of the present invention. It is a perspective view explaining the arrangement | positioning relationship between the air-core coil and guide member of 3rd Example of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the manufacturing method of the surface mount inductor of 1st Example of this invention, (a) is a top view, (b) is an ABCD combined sectional view of (a). It is a figure explaining the manufacturing method of the surface mount inductor of the 3rd Example of this invention. It is a perspective view of the surface mount inductor of the 3rd example of the present invention.

  Embodiments of a method for manufacturing a surface mount inductor according to the present invention will be described below with reference to the drawings.

(First embodiment)
A first embodiment of a method for manufacturing a surface mount inductor according to the present invention will be described with reference to FIGS. First, the air core coil used in the first embodiment will be described. FIG. 1 shows a perspective view of an air core coil used in the first embodiment. As shown in FIG. 1, the air-core coil 1 used in the first embodiment is provided with a winding part 1a by winding a flat wire around two stages of outer and outer windings, and both end parts 1b are sandwiched by the winding part 1a. Pulled out to face each other.

  Next, the guide member used in the first embodiment will be described. FIG. 2 is a perspective view of the guide member used in the first embodiment. The guide member used in the first embodiment is made of a liquid crystal polymer using an injection molding method. As shown in FIG. 2, the guide member 2 has a flat surface portion 2a and two columnar convex portions 2b, and the columnar convex portions 2b are provided so as to face the peripheral portion of the flat surface portion 2a.

Next, the sealing material used in the first embodiment will be described. In this embodiment, as the sealing material, an iron-based metal magnetic powder and an epoxy resin are mixed and granulated into a powder form. At this time, the sealing material is such that the thermosetting resin therein is in an uncured state or a semi-cured state.

  Next, a method for manufacturing the surface-mount inductor according to the first embodiment will be described with reference to FIGS. FIG. 3 is a perspective view for explaining the positional relationship among the air-core coil, the guide member, and the tablet according to the first embodiment. First, as shown in FIG. 3, pressure-preliminary molding of the sealing material is performed to produce plate-like tablets 3 a and 3 b. At this time, the tablets 3a and 3b are manufactured such that the thermosetting resin contained therein is in an uncured state or a semi-cured state.

  Next, the positional relationship among the air-core coil 1, the guide member 2, and the tablets 3a and 3b will be described. FIG. 4 shows the arrangement of the air-core coil, the guide member and the tablet in the molding die of the first embodiment, where (a) is a top view and (b) is a cross-sectional view taken along line AB of (a). As shown in FIG. 3, the winding part 1 a of the air-core coil 1 is placed on the flat part 2 a of the guide member 2. And the both ends 1b of the air-core coil 1 are arrange | positioned so that the outer side surface of the columnar convex part 2b of the guide member 2 may each be followed.

  As shown in FIG. 4, in the first embodiment, a molding die having a die 4, an upper punch 5a, and a lower punch 5b is used. The die 4 includes a split die 4a and a split die 4b, and the die 4 is combined with an upper punch 5a and a lower punch 5b to form a cavity (molding portion) of the molding die. The upper punch 5a and the lower punch 5b can be fitted in an opening formed by combining the split dies 4a and 4b, and can slide in the vertical direction. As shown in FIGS. 3 and 4B, the tablet 3a, the guide member 2 on which the air-core coil 1 is placed, and the tablet 3b are loaded in this order in the molding die. If arrange | positioned in this way, the air-core coil 1 will be arrange | positioned in a suitable height within a shaping | molding die by the thickness of the guide member 2 and the tablet 3b. As shown in FIGS. 4A and 4B, each of both end portions 1b of the air-core coil 1 is formed by a columnar convex portion 2b of the guide member 2 and inner wall surfaces of the split dies 4a and 4b. The both ends 1b of the air-core coil 1 are fixed at appropriate positions.

  After the air-core coil 1, the guide member 2, and the tablets 3a and 3b are set in the cavity of the molding die, compression molding is performed at a temperature equal to or higher than the softening temperature of the resin in the sealing material, for example, 150 ° C., and cured to FIG. A core 6 as shown is obtained. Both end portions 1b of the air-core coil 1 are sandwiched between the columnar convex portions 2b of the guide member 2 and the inner wall surface of the molding die and sealed by compression molding at a temperature equal to or higher than the softening temperature of the thermosetting resin in the tablets 3a and 3b. The For this reason, the tablets 3a and 3b are in a softened state during molding, and sealing is performed so that at least a part of the end portion 1b is exposed on the side surface of the core 6 without shifting both end portions 1b of the air-core coil 1.

  Next, the core 6 is taken out from the molding die and subjected to sand blasting to remove the deburring and the coating on the exposed surfaces of both ends 1b, and then a conductive resin is applied to the surface of the core 6 so as to be connected to the ends 1b. Apply. Subsequently, a plating process is performed to form the external electrode 7 to obtain the surface mount inductor shown in FIG. Note that the electrode formed by plating may be formed by appropriately selecting one or a plurality of electrodes such as Ni, Sn, Cu, Au, and Pd.

(Second embodiment)
A second embodiment of the surface-mount inductor according to the present invention will be described with reference to FIGS. In the second embodiment, the air-core coil, the sealing material, and the molding die used in the first embodiment are used. In addition, description of the part which overlaps with 1st Example is omitted.

  First, the guide member used in the second embodiment will be described. FIG. 7 is a perspective view of a guide member used in the surface mount inductor according to the second embodiment of the present invention. The guide member used in the second embodiment is produced by pressure-molding alumina powder. As shown in FIG. 7, the guide member 12 has a flat surface portion 12a and two columnar convex portions 12b, and the columnar convex portions 12b are provided so as to face the peripheral edge portion of the flat surface portion 12a. Further, the guide member 12 is produced in a shape having a through hole 12c in the center of the flat portion 12a.

  Next, a method for manufacturing the surface-mount inductor according to the second embodiment will be described with reference to FIGS. FIG. 8 shows the arrangement of the air core coil, guide member and tablet of the second embodiment, FIG. 9 shows the manufacturing process of the surface mount inductor of the second embodiment of the present invention, (a) is a top view, (b) ) Is a cross-sectional view taken along line AB of (a).

  First, the arrangement relationship among the air-core coil 1, the guide member 12, and the tablets 13a, 13b, and 13c will be described. As shown in FIG. 8, the winding part 1 a of the air-core coil 1 is placed on the flat part 12 a of the guide member 12. And the both ends 1b of the air-core coil 1 are arrange | positioned so that the outer side surface of the columnar convex part 12b of the guide member 12 may each be met. Next, the powdery sealing material is preformed into two plate-like tablets 13a and 13b and one elliptical columnar tablet 13c using compacting. As shown in FIGS. 8 and 9B, the guide member 12 on which the air-core coil 1 is placed is sandwiched between the plate-like tablets 13 a and 13 b, and the hollow portion of the air-core coil 1 and the through hole 12 c of the guide member 12. The molding die is loaded so that the elliptical columnar tablet 13c is arranged. If arrange | positioned in this way, the air-core coil 1 will be arrange | positioned in an appropriate height within a shaping die by the thickness of the guide member 12 and the tablet 13b. 9A and 9B, both end portions 1b of the air-core coil 1 are respectively formed by columnar convex portions 12b of the guide member 12 and inner wall surfaces of the split dies 4a and 4b. The both ends 1b of the air-core coil 1 are fixed at appropriate positions.

  After setting the air core coil 1, the guide member 12, and the tablets 13a, 13b, and 13c in the cavity of the molding die, compression molding is performed at 150 ° C. As in the first embodiment, both end portions 1b of the air-core coil 1 are sandwiched between the columnar convex portions 12b of the guide member 12 and the inner wall surface of the molding die, and the thermosetting resin in the tablets 13a, 13b, 13c. It is sealed by compression molding above the softening temperature. For this reason, the tablets 13a, 13b, and 13c are softened during molding, and are sealed so that at least a part of the end 1b is exposed on the side surface of the core 16 without shifting the both ends 1b of the air-core coil 1. To do. The core 16 is taken out from the molding die and subjected to sand blasting to remove burrs and the coating on the exposed surfaces of both ends 1b. Then, solder is used on the surface of the core 16 to connect to the ends 1b. The surface mount inductor shown in FIG. 10 is obtained by attaching the external electrode 7. In addition, what is necessary is just to produce a metal terminal using a phosphor bronze board, a copper plate, etc., and may perform a tin plating process etc. as needed.

(Third embodiment)
A third embodiment of the surface mount inductor according to the present invention will be described with reference to FIGS. In the third embodiment, the sealing material used in the first embodiment and the second embodiment is used. In addition, description of the part which overlaps with 1st Example and 2nd Example is omitted.

  First, an air core coil used in the third embodiment will be described. FIG. 11 shows a perspective view of an air core coil used in the third embodiment. As shown in FIG. 11, using a winding core having an elliptical cross-sectional shape, a rectangular conductor having a self-bonding film is wound around two outer and outer windings to provide a winding portion 21a, The air-core coil 21 was produced so that 21b was pulled out to the same side surface side.

  Next, the guide member used in the third embodiment will be described. FIG. 12 is a perspective view of a guide member used in the third embodiment. The guide member used in the third embodiment is produced by press-molding alumina powder as in the second embodiment. As shown in FIG. 12, the guide member 22 has a flat portion 22a and two columnar convex portions 22b, and the columnar convex portions 22b are provided so as to face the peripheral portion of the flat portion 22a. Further, the guide member 22 is formed in a shape having an elliptic columnar convex portion 22c in the center of the flat portion 22a.

  Next, a method for manufacturing the surface-mount inductor according to the third embodiment will be described with reference to FIGS. FIG. 13 shows the positional relationship between the air-core coil and the guide member of the third embodiment. 14A and 14B show a manufacturing process of the surface-mount inductor according to the third embodiment, in which FIG. 14A is a top view and FIG. 14B is a cross-sectional view taken along the line ABCD of FIG. First, the molding die used in the third embodiment will be described. As shown in FIGS. 14A and 14B, a molding die having a die 24, a lower die 25, and a punch 26 is used in the third embodiment. The die 24 includes a split die 24a and a split die 24b, and the die 24 is combined with the lower die 25 to form a molding die cavity (molding portion). The punch 26 is fitted with an opening formed by combining the split dies 24a and 24b, and can slide in the vertical direction.

  Next, the arrangement relationship between the air core coil 21 and the guide member 22 will be described. As shown in FIG. 13, the winding part 21 a of the air-core coil 21 is placed on the flat part 22 a of the guide member 22. At this time, it mounts so that the convex part 22c of the guide member 22 may penetrate | invade in the hollow part of the air-core coil 21. FIG. As a result, the air-core coil 21 is easily positioned to an appropriate position on the guide member 22. And the both ends 21b of the air-core coil 21 are arrange | positioned so that the outer side surface of the columnar convex part 22b of the guide member 22 may each be met.

  As shown in FIG. 14, a powdery sealing material 27 weighed from the opening of the die 24 is put into the cavity, and the surface thereof is flattened using the punch 26. Next, the air-core coil 21 and the guide member 22 having the above-described arrangement relationship are placed on the flattened sealing material 27. At this time, each of both end portions 21b of the air-core coil 21 is loaded into the cavity so as to be sandwiched between the columnar convex portion 22b of the guide member 22 and the split die 24a. Next, the powder sealing material 27 weighed on the air core coil 21 and the guide member 22 is put into the cavity, and the punch 26 is set in the opening of the die 24.

  After the air-core coil 21, the guide member 22, and the sealing material 27 are put into the cavity of the molding die, the core 28 as shown in FIG. Both end portions 21b of the air-core coil 21 are sealed with a sealing material while being sandwiched between the columnar convex portions 22b of the guide member 22 and the inner wall surface of the molding die. Therefore, both end portions 21b of the air-core coil 21 are sealed so that at least a part thereof is exposed on one side surface of the core 28 without being displaced.

  Next, as in the first embodiment, the core 28 is subjected to sandblasting to remove the deburring and the coating on the exposed surfaces of both end portions 21b, and then the side surface of the core 28 where the end portion 21 of the air-core coil 21 is exposed. A conductive paste is transferred onto and cured. As a result, the conductive paste and the internal air core coil 1 are conducted. Finally, plating is performed to form the external electrode 29 on the surface of the conductor paste, and the surface mount inductor shown in FIG. 16 is obtained. If the external electrode is formed only on one side surface of the core as in the third embodiment, the electrode area is small compared to the case where the external electrode is formed over five surfaces as in the first embodiment. An eddy current due to magnetic flux is hardly generated, which is advantageous in terms of circuit efficiency.

  In the said Example, the iron-type metal magnetic powder was used for the filler as a sealing material, and the epoxy resin was used for resin. By using iron-based metal magnetic powder, a surface-mount inductor having excellent DC superposition characteristics can be produced. However, not limited to this, for example, ferrite magnetic powder or glass powder may be used as the filler. Further, 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 as the resin.

  In the above embodiment, an air-core coil wound around two stages of outer and outer windings is used as the coil. However, the present invention is not limited to this. For example, a winding method such as edgewise winding or a coil having a circular or rectangular shape is used. Also good. In addition, when a round wire is used without using a flat conducting wire, the end portion may be crushed to create a flat surface.

  In the above embodiment, liquid crystal polymer and alumina are used as the guide member. However, the material is not limited to this, and a material having high moldability may be used. For example, thermoplastic resin such as polyamide resin or saturated polyester resin, epoxy resin or polyimide resin, etc. A thermosetting resin or a ceramic material such as ferrite or magnesia may be used. At this time, if the guide member is made of a magnetic material such as ferrite, the loss of magnetic properties can be reduced as compared with that made of resin. Moreover, when producing with resin, it is more preferable to select resin excellent in heat resistance, such as engineering plastic and super engineering plastic. In the first embodiment, the guide member is manufactured by injection molding. However, the present invention is not limited to this. For example, a resin molding method such as transfer molding or compression molding may be used.

1 and 2: Air-core coil 1a, 21a: Winding part 1b, 21b: End part 2, 12, 22: Guide member 2a, 12a, 22a: Plane part 2b, 12b, 22b: Columnar convex part 12c: Through-hole 22c: Protrusions 3a, 3b, 13a, 13b, 13c: Tablet 4, 24: Die 4a, 4b, 24a, 24b: Split die 5a: Upper punch 5b: Lower punch 6, 16, 28: Core 7, 17, 29: External electrode 25: Lower mold 26: Punch 27: Sealing material

Claims (5)

In a method for manufacturing a surface mount inductor in which a coil is sealed with a sealing material using a molding die,
The coil around which a conducting wire having a flat cross section is wound;
The encapsulant comprising a resin and magnetic powder;
Using a guide member formed into a shape having a columnar convex portion at the peripheral edge of the flat plate shape,
The coil is placed on the guide member, and both ends of the coil are loaded into the molding die along the outer side surface of the columnar convex portion of the guide member,
With both ends of the coil sandwiched between the outer side surface of the columnar convex portion of the guide member and the inner wall surface of the molding die, the coil and the guide are formed using a resin molding method or a powder molding method. The member is sealed with the sealing material to form a molded body,
A method of manufacturing a surface-mount inductor, comprising: providing an external electrode on the surface or outer periphery of the molded body, which is connected to a portion of at least a part of both ends of the coil exposed on the surface of the molded body. In a method for manufacturing a surface mount inductor in which a coil is sealed with a sealing material using a molding die,
A coil having a circular cross-section, wound around the both ends and provided with a flat surface,
The encapsulant comprising a resin and magnetic powder;
Using a guide member formed into a shape having a columnar convex portion at the peripheral edge of the flat plate shape,
The coil is placed on the guide member, and the flat surfaces of both ends of the coil are loaded along the outer side surface of the columnar convex portion of the guide member into the molding die.
With both ends of the coil sandwiched between the outer side surface of the columnar convex portion of the guide member and the inner wall surface of the molding die, the coil and the guide are formed using a resin molding method or a powder molding method. The member is sealed with the sealing material to form a molded body,
A method of manufacturing a surface-mount inductor, comprising: providing an external electrode on the surface or outer periphery of the molded body, which is connected to a portion of at least a part of both ends of the coil exposed on the surface of the molded body. Pre-molding the sealing material to form at least one plate-like tablet,
The method for manufacturing a surface-mount inductor according to claim 1, wherein the plate and the guide member are aligned in the height direction in the molding die.   4. The method for manufacturing a surface-mount inductor according to claim 1, wherein the guide member is made of resin or ceramics.   A surface-mount inductor manufactured using the method for manufacturing a surface-mount inductor according to claim 1.

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