JP2007019402A - Coil-sealing resin-molded reactor, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil-sealing resin-molded reactor which can deal favorably with requiring the reduction of its manufacturing cost, while suppressing the deterioration of its magnetic characteristic and its losses. <P>SOLUTION: The coil-sealing resin-molded cheap reactor is constituted by molding a rectangular-wire coil 1 with a resin, and by coating thereafter the resin-molded rectangular-wire coil 1 in a surrounding way with another resin having an entrapped iron powder therein whose surface has no insulating coated film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improved coil-sealed resin-molded reactor manufactured by molding soft magnetic powder and a method for manufacturing the same.

  As a manufacturing method of a reactor (hereinafter also referred to as a choke coil) that is an inductance component used in an electric circuit or an electronic circuit, a coil having a structure in which a resin mixed with soft magnetic ferrite powder is molded to surround the coil Sealing type resin molding reactors are known. For example, Patent Document 1 below proposes a coil-sealed resin-molded reactor (coil component) in which a polyamide resin filled with ferrite powder is molded and a coil is sealed. Patent Document 2 below is a coil-sealed resin molded reactor (coil part) in which a resin filled with soft magnetic ferrite powder and inorganic powder (for example, silica powder) is molded and the coil is sealed. A coil-sealed resin molding reactor in which a resin filled with a filler composed of ferrite powder and inorganic powder is molded and the coil is sealed, and the filler is 60-80 wt% with respect to the resin, ferrite It has been proposed that the powder be 60-90% of the filler.

This type of coil-sealed resin-molded reactor has a resin-molded magnetic path member that completely seals the coil as compared with a sintered reactor in which a coil is wound around a conventional sintered core. It has the advantage that magnetic flux leakage can be reduced and electromagnetic noise can be reduced, the waterproofness and electrical insulation of the coil can be improved, and the manufacturing process can be simplified.
JP-A-6-176946 Japanese Patent Publication No. 7-118420 (Japanese Patent Laid-Open No. 3-96202)

  However, the above-described conventional coil-encapsulated resin-molded reactor is expensive because ferrite powder is used as the soft magnetic powder, and there is a problem that it cannot meet the demand for reduction in manufacturing cost. In addition, the magnetic properties of ferrite used as a soft magnetic powder, for example, the saturation magnetic flux density is inferior to that of pure iron or silicon alloy steel, so it is necessary to relatively increase the amount of use in order to obtain the required magnetic properties. In addition to the problem that the material cost further increases, there is also a problem that it is impossible to meet the demand for reducing the size and weight of the reactor.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a coil-sealed resin-molded reactor that can satisfactorily meet demands for reducing manufacturing costs while suppressing deterioration of magnetic properties.

  The coil-sealed resin-molded reactor of the present invention that solves the above problems includes a coil and a soft magnetic resin molded core that seals the coil, and the soft magnetic resin-molded core is filled with soft magnetic powder. In a coil-sealed resin molding reactor formed by molding a soft magnetic powder-filled resin, which is a resin, into a predetermined shape, the resin-molded reactor for sealing the coil is provided, and the soft magnetic resin-molded core includes the coil The soft magnetic powder is molded into a shape for sealing the sealed resin mold member, and is characterized by being composed of iron powder having no insulating film on the surface. As a result, it is possible to realize a coil-sealed resin-molded reactor that can satisfactorily meet demands for manufacturing cost reduction while suppressing deterioration and loss of magnetic characteristics.

  The advantages of the reactor of the present invention will be described in more detail.

  According to the present invention, similar to a conventional coil-sealed resin-molded reactor, since the soft magnetic resin-molded core seals the coil, the magnetic flux leakage to the outside can be reduced, and electromagnetic noise can be reduced. It has the advantage of improving the waterproofness and electrical insulation of the glass, and the advantage of simplifying the manufacturing process.

  Furthermore, in the present invention, since the coil-sealed resin-molded reactor is formed using iron powder on which no insulating film is formed, the manufacturing cost is greatly increased as compared with the conventional coil-sealed resin-molded reactor that uses expensive ferrite powder. Can be reduced. As the iron powder, silicon alloy iron powder with less eddy current loss is suitable in addition to pure iron powder excellent in magnetic properties such as saturation magnetic flux density. Moreover, since the process of forming an insulating film on the surface of these iron powders is not necessary, the manufacturing cost can be significantly reduced in addition to the simple manufacturing process.

  However, although the coil-sealed resin-molded reactor of the present invention is inexpensive and has excellent magnetic properties, it uses conductive iron powder, so there is a risk of current leakage between the turns of the coil. Therefore, in the present invention, after the coil is resin-molded in advance, the resin-molded coil is sealed and a closed magnetic circuit is formed with an iron powder mixed resin (soft magnetic powder-filled resin). Thereby, while being able to prevent the current leak between the turns of the coil in a core satisfactorily, even when a crack arises in a core, the ground fault of a coil can be prevented favorably.

  In a preferred embodiment, the outer surface of the resin mold member has a protrusion or a flange. In this way, the adhesion between the resin molded coil and the iron powder-containing resin molded core can be improved, so that a gap is generated between the two due to the difference in thermal expansion coefficient or vibration between them, and moisture and the like enter. This can be prevented.

  A second invention that solves the above-described problems includes a coil and a soft magnetic resin molded core that seals the coil, and the soft magnetic resin molded core is a resin filled with soft magnetic powder. In a coil-sealed resin molding reactor formed by molding a filling resin into a predetermined shape, the coil is molded with resin to form a resin-molded coil, and the resin-molded coil is set in a case with one end opening, The soft magnetic powder-filled resin mixed with iron powder having no insulating film is filled in the case and solidified. In this way, since the injection and solidification of the iron powder-containing resin can be performed by so-called potting, the manufacturing process can be simplified, and the case used for potting can be used for core protection.

  Hereinafter, a preferred embodiment of the coil-sealed resin-molded reactor of the present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating a manufacturing process. (A) shows a rectangular wire coil, (b) shows a resin molded coil, and (c) shows a resin molded reactor.

  First, the rectangular copper coil 1 is formed by winding a long copper plate shown in FIG. In this embodiment, the thickness of the flat wire is 1 mm, the width is 3 mm, and the number of turns is 100. A gap of 1 to 2 mm was secured between the turns of the flat wire coil 1.

  Next, the rectangular coil 1 is put into a mold, a resin liquid is injected, and the resin mold coil 2 is manufactured by curing. The minimum coating thickness of the mold resin on the flat wire coil 1 was 1 mm to 3 mm. As the mold resin, a thermosetting resin excellent in heat resistance is preferable, and an epoxy resin or the like is preferable. Reference numeral 3 denotes terminal portions at both ends of the rectangular wire coil 1.

  Next, the resin molded coil 2 taken out from the mold is set in the case 4 with the upper end opening, and the terminal portion 3 is protruded upward from the case 4. The case 4 is preferably an aluminum pressed product or an aluminum drawn product, but a heat resistant resin such as polyimide may be used. However, the case must have heat resistance to withstand the heating of the next process.

  Finally, the case 4 is set in a vacuum heating furnace, and an iron resin-mixed epoxy resin liquid mixed with a necessary weight percent of silicon alloy iron powder (Fe-Si (6.5%)) is poured into the case 4 and predetermined. The reactor is completed by maintaining the heating temperature for a predetermined time to solidify the resin powder mixed with iron powder. Reference numeral 5 denotes a core made of a solidified iron powder mixed resin. The iron powder-mixed resin liquid may be kneaded for a predetermined time after the iron powder is put into the resin liquid. Alternatively, iron powder and resin powder may be kneaded and formed. What is important is that the resin mold coil is formed in a cylindrical shape to form a closed magnetic circuit in which the iron powder mixed resin body, that is, the core 5 is linked to the resin mold coil.

(Modification)
Preferably, as shown in FIG. 2, protrusions (or flanges) 6 are formed on the surface of the resin mold coil 2. If it does in this way, since both contactability improves significantly, it can prevent that a peeling clearance gap arises between both by the difference in the thermal expansion coefficient of the resin mold coil 2 and the core 5. FIG.

(Modification)
As the mold resin and the resin of the core 5, in addition to epoxy resin, polyimide, phenol, polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyamide (PA), or the like may be used.

(Modification)
A mixed powder obtained by mixing iron powder and resin powder may be melted in the case 4. Naturally, the softening point of the mold resin is preferably set higher than the melting point of the resin powder.

It is a figure which shows the manufacturing process of a coil sealing type resin molding reactor. It is a partial schematic cross section which shows the deformation | transformation aspect of the resin mold coil of a coil sealing type resin molding reactor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat wire coil 2 Resin mold coil 3 Flat wire coil terminal part 4 Case 5 Core (Iron powder mixed resin body)
6 protrusions (or buttocks)

Claims (3)

A coil and a soft magnetic resin molding core for sealing the coil, and the soft magnetic resin molding core is formed by molding a soft magnetic powder-filled resin, which is a resin filled with soft magnetic powder, into a predetermined shape. In the coil-sealed resin molded reactor,
A resin mold member for sealing the coil;
The soft magnetic resin molded core is molded into a shape that seals a resin mold member that seals the coil,
A coil-sealed resin-molded reactor, wherein the soft magnetic powder is made of iron powder having no insulating film on the surface. In the coil-sealed resin-molded reactor according to claim 1,
The outer surface of the resin mold member is a coil-sealed resin molded reactor having protrusions or flanges. A coil and a soft magnetic resin molding core for sealing the coil, and the soft magnetic resin molding core is formed by molding a soft magnetic powder-filled resin, which is a resin filled with soft magnetic powder, into a predetermined shape. In the coil-sealed resin molded reactor,
The coil is molded with resin to form a resin mold coil,
Set the resin mold coil in the case of one end opening,
A method for producing a coil-sealed resin-molded reactor, wherein the case is filled with the soft magnetic powder-filled resin mixed with iron powder having no insulating film on the surface and solidified.

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