JP2013211331A - Surface mount multiphase inductor and manufacturing method therefor - Google Patents

Abstract

A surface-mount multiphase inductor excellent in mountability and a method for manufacturing the same are provided.
A surface-mount multi-phase inductor has a plurality of coils wound with a conductive wire and flat at both ends. And it has the core which includes the some coil which consists mainly of magnetic powder and a binder. An external electrode formed on one surface of the core. Both ends of the coil lead wires are set to the outermost periphery. A plurality of coils are included in the core so that the winding axis of the coil is parallel to the surface of the core on which the external electrode is formed.
[Selection] Figure 8

Description

  The present invention relates to a surface mount multiphase inductor and a method for manufacturing the same.

  In recent years, high-density mounting is progressing along with miniaturization and thinning of digital devices and the like, and there is an increasing demand for miniaturization and low profile of electronic components. Therefore, in the patent documents 1 and 2 previously filed by the applicant, the applicant uses a small coil using a coil and a pre-formed tablet in which a rectangular conductor is wound in a spiral shape so that both ends thereof are drawn to the outer periphery. A surface mount inductor and its manufacturing method were proposed.

JP 2010-245473 A Japanese Patent Application No. 2011-017581 JP2000-036414

  When the circuit pattern is such that a plurality of inductors with the same characteristics can be mounted in parallel on the circuit board, mounting efficiency is improved by installing a plurality of inductors in one package rather than mounting a plurality of single products. Can do. Therefore, there is a demand for a surface mount multiphase inductor in which a plurality of inductors are packaged.

  As a conventional technique of the surface mount multiphase inductor, for example, a plurality of coils in which a conductor is wound around a winding core are arranged on a magnetic sheet as shown in Patent Document 3, and magnetic ceramic slurry for wet pressing is used as a mold. There is a technique of filling and molding and sealing a plurality of coils. In the case of this method, since a plurality of coils are arranged on one magnetic sheet and sealed with a highly fluid magnetic ceramic slurry, there is a concern about displacement of coils and displacement of ends. And this method can be realized only with an array structure in which coils are arranged in parallel in the same direction. When the number of coils increases, especially when a surface mount multiphase inductor is created using four or more coils. It becomes a chip component with a large aspect ratio. If the chip component has a shape with a large aspect ratio, there is a possibility that the mounting space on the circuit board becomes a problem, and there is a concern that the product strength becomes a problem with respect to the bending stress.

  Accordingly, an object of the present invention is to provide a surface-mount multiphase inductor with excellent productability and high product strength, and a method for manufacturing the same.

  In order to solve the above-described problems, a surface-mounted multiphase inductor according to the present invention has a plurality of coils wound around a conductive wire and flat at both ends. And it has the core which includes the some coil which consists mainly of magnetic powder and a binder. An external electrode formed on one surface of the core. Both ends of the coil lead wires are set to the outermost periphery. A plurality of coils are included in the core so that the winding axis of the coil is parallel to the surface of the core on which the external electrode is formed.

  In the surface mount multiphase inductor according to the present invention, since the external electrode is formed on one surface of the core, a bottom electrode structure is formed, and the height of the surface mount multiphase inductor can be reduced. Since a plurality of coils are packaged in one package, the mounting efficiency can be increased.

  In the method for manufacturing a surface-mounted multiphase inductor according to the present invention, it is easy to position each coil and its end using a tablet. Therefore, displacement of the coil and its end is prevented. By using a plurality of coils and tablets corresponding to the coils, it is possible to flexibly cope with design changes such as the number and arrangement of coils.

  Since the manufacturing method of the surface mount multiphase inductor of the present invention can easily expose the end portion of the coil on one surface of the core portion, it is easy to create the surface mount multiphase inductor having the bottom electrode structure. Can do. Since the end portion of the coil is exposed on one surface of the core portion, it is possible to reduce the manufacturing cost without complicating the operation of removing the insulating film from the conductive wire forming the coil and the formation of the external electrode.

The perspective view of the coil and tablet used in the 1st example of the present invention. The perspective view explaining the state which combined the coil and tablet of the 1st Example of this invention. The perspective view explaining the molding die used in the 1st example of the present invention. The top view which shows arrangement | positioning with the shaping die of the coil and tablet of 1st Example of this invention. Sectional drawing corresponding to the AA cross section of FIG. 4 explaining a part of manufacturing process of the surface-mount multiphase inductor of 1st Example of this invention. Sectional drawing corresponding to the AA cross section of FIG. 4 explaining a part of manufacturing process of the surface-mount multiphase inductor of 1st Example of this invention. The perspective view of the core part of the 1st Example of this invention. 1 is a perspective view of a surface-mount multiphase inductor according to a first embodiment of the present invention. FIG. The perspective view of the coil and tablet used in the 2nd Example of this invention. The perspective view explaining the molding die used in the 2nd example of the present invention. The top view which shows arrangement | positioning with the shaping die of the coil and tablet of 2nd Example of this invention. Sectional drawing corresponding to the ABCD combined cross section of FIG. 11 explaining a part of manufacturing process of the surface mount multiphase inductor of 2nd Example of this invention. Sectional drawing corresponding to the ABCD combined cross section of FIG. 11 explaining a part of manufacturing process of the surface mount multiphase inductor of 2nd Example of this invention. The perspective view of the core part of the 2nd Example of this invention. The perspective view of the surface-mount multiphase inductor of the 2nd Example of this invention.

  Hereinafter, a surface-mount multiphase inductor and a manufacturing method thereof according to the present invention will be described with reference to the drawings.

(First embodiment)
A method for manufacturing the surface-mounted multiphase inductor according to the first embodiment of the present invention will be described with reference to FIGS. First, the coil and tablet used in the embodiment of the present invention will be described. FIG. 1 shows a perspective view of a coil and a tablet used in an embodiment of the present invention. As shown in FIG. 1, using a winding core having an elliptical cross section, a rectangular wire is wound around two outer and outer windings so that both end portions 1b are at the outermost periphery to form a winding portion 1a to form a coil 1. obtain. At this time, both end portions 1b of the coil 1 are drawn out to the same side surface side.

  Next, the tablet used in the embodiment of the present invention will be described. In this embodiment, a sealing material obtained by mixing iron-based metal magnetic powder and an epoxy resin and granulating the powder is used. In this example, the filling amount of the iron-based metal magnetic powder was adjusted so that the permeability of the sealing material was 25. A tablet is produced using this sealing material. As shown in FIG. 1, the tablet 2 and the plate-like tablet 3 are formed by pressure molding. In this example, in order to increase the strength of the tablet 2, the heat treatment was further performed to make the sealing material semi-cured. As shown in FIG. 1, the tablet 2 has a shape having two columnar convex portions 2 a and an elliptical positioning convex portion 2 b corresponding to the air core of the coil 1 on the periphery of the flat portion so as to surround the coil 1. Form. As shown in FIG. 2, the coil 1 is combined so as to be sandwiched between the tablet 2 and the plate-like tablet 3. At this time, both end portions 1b of the coil 1 are arranged along the outer side surface of the columnar convex portion 2a.

  Next, the molding die used in the first embodiment and the arrangement of coils and tablets in the molding die will be described. FIG. 3 shows a perspective view for explaining the molding die used in the first embodiment, and FIG. 4 shows a top view for explaining the arrangement of the coil and the tablet in the molding die. As shown in FIG. 3 and FIG. 4, a molding die having an upper die 4, a lower die 5, and a punch 6 composed of a split die 4 a and a split die 4 b is used. A cavity 7 is formed by combining the upper mold 4 and the lower mold 5. Six cavities 7 in which the coil 1, the tablet 2 and the plate tablet 3 shown in FIG. At this time, it arrange | positions so that the edge part 1b of all the coils may become the opening part side of a shaping die.

  Next, formation of a core part is demonstrated. 5 and 6 are cross-sectional views corresponding to the AA cross section of FIG. 4 for explaining a part of the manufacturing process of the surface mount multiphase inductor of the first embodiment. As shown in FIG. 5, the punch 6 is set and the mold is preheated. At this time, the end portion 1 b of the coil 1 is put between the columnar convex portion 2 a of the tablet 2 and the punch 6. In this embodiment, the molding die is preheated to a temperature higher than the softening temperature of the sealing material, and the tablet 2 and the plate-like tablet 3 are in a softened state.

  As shown in FIG. 6, the six tablets 2 and the six plate-like tablets 3 are integrated by applying pressure using the punch 7, and the sealing material is cured. At this time, the tablet 2 and the plate-like tablet 3 are in a softened state, and are integrated so as to easily seal the six coils 1. And the both ends 1b of the coil 1 are sealed in a state where at least a part thereof is buried in the sealing material without being displaced. And the core part 7 obtained by hardening a sealing material is taken out from a shaping die. As shown in FIG. 7, the plane of all end portions 1 b of the coil 1 is exposed on one surface of the core portion 8.

  Next, sandblasting is performed to remove the deburred and exposed coating on the surface of both ends 1b, and a conductive paste is applied to the surface of the core 8 where the coil end 1b is exposed by a printing method and cured. As a result, the conductive paste and the internal coil 1 are conducted. Finally, plating is performed to form the external electrode 9 on the surface of the conductive paste, and a surface-mount multiphase inductor as shown in FIG. 8 is obtained. 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 multiphase inductor according to the present invention will be described with reference to FIGS. In the second embodiment, a surface mount multiphase inductor including three coils is produced using a sealing material having the same composition as that of the first embodiment and a similar molding die. In addition, description of the part which overlaps with 1st Example is omitted.

  First, the coil and tablet used in the second embodiment will be described. FIG. 9 shows a perspective view of the coil and tablet used in the embodiment of the present invention. As shown in FIG. 9, using a winding core having an elliptical cross section, a rectangular wire is wound around two outer and outer windings so that both ends 11b are at the outermost periphery to form a winding portion 11a to form a coil 11. obtain. At this time, both end portions 11b of the coil 11 are drawn once so as to face each other with the winding portion 12a interposed therebetween, and further bent so as to be drawn to the same side surface side.

  Next, a tablet is produced using the sealing material of the same composition used in the first embodiment. The first tablet 12 and the second tablet 13 are created by pressure molding. In this embodiment, in order to increase the strength of the first tablet 12 and the second tablet 13, heat treatment was further performed to make the sealing material semi-cured. As shown in FIG. 9, the 1st tablet 12 is formed in the shape which has the two columnar convex parts 12a in the periphery of a plane part so that the coil 11 may be enclosed. Both end portions 11b of the coil 11 are arranged along the outer side surface of the columnar convex portion 2a. The 2nd tablet 13 is formed in the shape which has the convex part 13a for an elliptical position corresponding to the air core of the coil 11. FIG. The coil 11 is combined so as to be sandwiched between the first tablet 12 and the second tablet 13.

  Next, formation of a molding die and a core part used in the second embodiment will be described. FIG. 10 is a perspective view for explaining a molding die used in the second embodiment. FIG. 11 shows a top view for explaining the arrangement of the coil and the tablet in the molding die. 12 and 13 are cross-sectional views corresponding to the cross section A-B-C-D in FIG. 11 for explaining a part of the manufacturing process of the surface mount multiphase inductor of the second embodiment. FIG. 14 is a perspective view for explaining the core part of the second embodiment. As shown in FIGS. 10 and 11, a molding die having an upper die 14, a lower die 15, and a punch 16 including a split die 14 a and a split die 14 b is used. A cavity 17 is formed by combining the upper mold 14 and the lower mold 15. As shown in FIGS. 11 and 12, three combinations of the coil 11, the first tablet 12, and the second tablet 13 were loaded in the cavity 17. If the coil 11, the first tablet 12, and the second tablet 13 are arranged in this way, the end 11b of the coil 11 is sandwiched between the columnar convex portion 12a of the first tablet 12 and the inner wall surface of the split die 14b. Thus, both ends 11b of the coil 11 are fixed at appropriate positions. Then, as shown in FIG. 13, the core portion 18 is formed by pressing and integrating the punch 16 so as to eliminate the interface between the first tablet and the second tablet by a compacting method. At this time, since the projecting portion 13a for positioning the second tablet 13 is in the air core of the coil 11, the core portion 18 is not deformed even when a large molding pressure is applied as in the compacting method. Can be molded. And the core part 18 was thermosetted and the core part 18 shown in FIG. 14 was obtained.

  Next, sandblasting is performed to remove the film on the surface of both end portions 11b exposed to deburring, and a conductive paste is applied to the surface on which the end portion 11b of the coil of the core portion 18 is exposed by a printing method and cured. As a result, the conductive paste and the internal coil 11 are conducted. Finally, plating is performed to form external electrodes 19 on the surface of the conductive paste, and a surface-mount multiphase inductor as shown in FIG. 15 is obtained.

  In the above-described example, a sealing material prepared by mixing magnetic powder with iron-based metal magnetic powder and resin with epoxy resin and having a magnetic permeability of 25 was used. However, the present invention is not limited thereto, and for example, ferrite magnetic powder or the like as magnetic powder, or magnetic powder subjected to surface modification such as insulation film formation or surface oxidation may be used. In addition, an inorganic substance such as glass powder may be added. 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-described embodiment, an elliptical coil wound in two stages is used. However, the present invention is not limited to this, for example, a coil having a large number of stages, for example, a circle, a rectangle, a fan, a semicircle, a trapezoid, A coil having a polygonal shape or a combination of them may be used. The shape of the coil is preferably a shape excluding a constant width figure from the viewpoint of preventing the rotation of the coil during molding.

  In the above embodiment, the application of the conductive paste and the plating process are used as the external electrode forming method. However, the present invention is not limited thereto, and for example, solder or the like may be used. The method for applying the conductive paste may also be a potting method or the like.

  In the above embodiment, the sandblasting process is used as a method for peeling the coating on the end surface of the coil. However, the present invention is not limited to this, and a peeling method such as mechanical peeling may be used. Moreover, you may peel the coating | film | coat of an edge part previously before forming a core part.

  In the above embodiment, the combination of the E-shaped core and the plate-shaped core and the combination of the U-shaped core and the T-shaped core are exemplified as the tablet. However, the present invention is not limited to this, and a combination of two E-shaped cores may be used. Moreover, not a non-hardened state but a semi-hardened state may be sufficient. The molding method may be appropriately selected according to the application such as a pressure molding method or cutting out from a sheet-like molded product.

1: Coil (1a: winding part, 1b: end part)
2: Tablet (2a: columnar convex part, 2b: convex part for positioning)
3: Plate-shaped tablet 4: Upper mold (4a, 4b: Split mold)
5: Lower mold 6: Punch 7: Cavity 8: Core part 9: External electrode 11: Coil (11a: Winding part, 11b: End part)
12: 1st tablet (12a: columnar convex part)
13: Second tablet (13a: convex portion for positioning)
14: Upper mold (14a, 14b: Split mold)
15: Lower mold 16: Punch 17: Cavity 18: Core part 19: External electrode

Claims (5)

Winding a conducting wire, and a plurality of coils whose ends are flat,
A core containing the plurality of coils mainly composed of magnetic powder and a binder;
An external electrode formed on one surface of the core,
So that both ends of the conductive wire of the coil are the outermost periphery,
A surface-mount multiphase inductor, wherein the plurality of coils are included in the core such that a winding axis of the coil is parallel to a surface of the core on which the external electrode is formed.   2. The surface-mount multiphase inductor according to claim 1, wherein the coil is formed in a shape excluding a fixed width figure using a flat wire. In a method for manufacturing a surface mount multiphase inductor in which a plurality of coils are sealed with a sealing material mainly made of resin and magnetic powder using a molding die,
A plurality of tablets are formed by pre-molding the sealing material into a shape having a columnar convex portion at the peripheral edge of the flat plate shape,
A plurality of coils are formed by winding a conductive wire having a flat shape at both ends so that both ends are at the outermost periphery using a winding core,
The coil is placed on the tablet, and a plurality of the coils having both end portions along the outer side surface of the columnar convex portion of the tablet are arranged with respect to one cavity in the molding die,
The core is formed by sealing the plurality of coils with the sealing material using a resin molding method or a powder molding method, and both ends of the plurality of coils are exposed on one surface of the core. And sealing so that the winding axis of the coil is parallel to the surface from which the end is exposed.
An external electrode is formed on the surface of the core exposed at the end. A method for manufacturing a surface-mount multiphase inductor.   4. The method of manufacturing a surface-mount multiphase inductor according to claim 3, wherein the tablet is further formed into a shape having a convex portion for positioning the coil. In the step of forming the core,
The coil and the sealing material are integrated to form a core portion in a state where the end of the coil is sandwiched between the columnar convex portion of the tablet and the inner wall surface or punch of the cavity. A method for manufacturing a surface-mounted multiphase inductor according to claim 3 or 4.

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