JPH05291066A - Inductor and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a small inductor which can have conductive material and magnetic material characteristics fully displayed and can be easily manufactured. CONSTITUTION:The powder of magnetic metal or ceramic and binder are mixed together and granulated for the formation of material powder, and the material powder concerned is press-molded into a molded body, containing a coiled core material 12' formed of organic compound and/or carbon fiber. The molded body is subjected to an extract operation and/or a thermal treatment in a following process to remove the binder and the coil core material 12'. whereby a degreased body provided with a through-hole can be obtained, the degreased body is sintered into a sintered body 11, and a conductor 12 is provided inside the through-hole of the sintered body 11 for the manufacture of an inductor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor composed of a magnetic material and a conductor, which is mainly used for noise prevention of electronic equipment and a method for manufacturing the inductor.

[0002]

2. Description of the Related Art Heretofore, this type of inductor has been used for noise prevention of electronic equipment as described above, and its element structure is a toroidal magnetic core wound with a conductor winding. Is versatile.

By the way, there is a remarkable demand for miniaturization of electronic devices in recent years, and accordingly, further miniaturization of inductors is desired. However, the smaller the size of an inductor with a structure in which a conductor winding is wound around the magnetic core,
The problem arises that winding of the conductor becomes difficult.

Therefore, a laminated inductor has been developed in which a conductor and a sheet made of magnetic powder are alternately laminated so that a part of the conductor has a contact point. This laminated inductor is manufactured by obtaining a green compact of a magnetic material in which a conductor coil is embedded and sintering the green compact.
Since such a laminated inductor has a structure in which a conductor coil is embedded in a magnetic core of a magnetic material, it has an advantage that it can be sufficiently miniaturized without leaking the magnetic flux generated by the conductor coil to the outside.

[0005]

However, in the case of the above-mentioned laminated inductor, the manufacturing process is complicated, and the manufacturing cost cannot be reduced. In addition, in the sintering process of the green compact, the constituent components of the conductor and the magnetic material are alternately diffused, so that there is a drawback that the characteristics of these respective materials cannot be sufficiently exhibited.

The present invention has been made to solve the above problems, and its technical problem is that it is small in size, and the characteristics of each material of a conductor and a magnetic material can be sufficiently exhibited, and moreover, it is easily obtained. The present invention provides an inductor and a manufacturing method thereof.

[0007]

According to the present invention, a coil made of an organic compound and / or carbon fiber is added to a raw material powder obtained by mixing and granulating a metal or ceramic powder as a magnetic material and a binder. A molding step of obtaining a molded body by press molding including a core material, a degreasing step of obtaining a degreased body having through holes by extracting the molded body and removing the binder and the coiled core material, and the degreased body. A method for manufacturing an inductor including a sintering step of sintering to obtain a sintered body and a conductor forming step of providing a conductor inside the through hole of the sintered body is obtained.

Further, according to the present invention, in the inductor manufacturing method, the degreasing step is performed by heat treatment.

Further, according to the present invention, an inductor formed by the above method of manufacturing an inductor can be obtained.

[0010]

In the present invention, the raw material powder is obtained by mixing and granulating the powder of metal or ceramics as the magnetic material and the binder in the first step in the manufacturing process of the inductor, and the raw material powder is mixed with the organic compound and / or A molded body is obtained by press molding including a coil-shaped core material made of carbon fiber. Since this molded product contains the fat component of the binder, it must be degreased. Therefore, in the next step, the molded body is extracted and / or heat-treated to remove the binder and the coil-shaped core material to obtain a degreased body having through holes, and the degreased body is sintered and fired in a further step. After obtaining the bonded body, a conductor is provided inside the through hole of the sintered body to manufacture an inductor. Such an inductor can be easily manufactured, and the material characteristics of the conductor and the magnetic material can be sufficiently exhibited.

[0011]

The inductor and the method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings.

First, a method of manufacturing an inductor will be briefly described with reference to the flowchart of the manufacturing process shown in FIG. First, for example, a powder of metal or ceramics and a binder are prepared as magnetic materials, and these are weighed and mixed and granulated (step S1) to obtain a raw material powder. Next, a coil-shaped core material made of an organic compound and / or carbon fiber is placed in a molding die,
The above-mentioned raw material powder (object to be molded) is filled in this mold (step S2), and press molding is performed (step S).
3). The steps up to this point may be referred to as a molding step, since a raw material powder including a core material is press-molded to obtain a molded body.

Further, the molded body obtained here is degreased by removing the binder and the core material by an extraction operation and / or a heat treatment (step S4). As a result, a degreased body having a through hole inside is obtained. Since this step removes the binder and the coil-shaped core material, it may be called a degreasing step. Subsequently, the degreased body is fired (step S5) to obtain a sintered body, and then a conductor is formed inside the through hole of the sintered body (conductivity formation / step S6) to obtain a coil. Finally, electrodes are formed on both ends of the coil (step S7).
In this way, an inductor containing a conductor inside a metal or ceramic sintered body is manufactured.

The inductor thus obtained is small in size, has good element efficiency, and can be manufactured at low cost. However,
Although various organic compounds or carbon fibers can be mentioned as the material of the core material, especially when carbon fibers are used, it is difficult to remove them by a method other than combustion, so magnetic materials whose characteristics deteriorate due to oxidation are targeted. It is better to avoid using it. Further, various polyolefins, copolymers, waxes, etc. may be mentioned as the material of the binder, and the material may be appropriately selected in consideration of the particle size and surface property of the raw material powder.

As a method of forming a conductor inside the through hole (hole) formed in the sintered body, various plating methods, casting method of hot metal, chemical vapor decomposition method, physical method Examples thereof include, but are not limited to, vapor phase decomposition methods.

The inductor obtained by the above-described manufacturing method will be specifically described below.

[Embodiment 1] FIG. 2A is a perspective view showing an inductor according to Embodiment 1, and FIG. 2B is a perspective view showing the shape of a molded body obtained by press molding of the inductor.

In FIG. 2 (B), the raw material powder is a Ni-Zn ferrite calcined powder having an average particle size of 0.4 μm and 50 v of a 5 wt% polyvinyl alcohol solution as a binder.
It was obtained by ol% mixing and granulation. Next, a coil-shaped core material 12 'made of carbon fiber and having a wire diameter of 0.5 mm was placed in a mold and press-molded to obtain a molded body 11'.
During molding, after the raw material powder is put into the mold so that the powder is sufficiently distributed between the coil-shaped core materials 12 ', the mold is vibrated to enhance the powder filling. I made a press.

Further, the molded body 11 'is heat-treated at 600 ° C. at a temperature rising rate of 5 ° C./Hr to remove the coil-shaped core material 12' composed of a binder and carbon fiber,
A degreased body (not shown) having a coiled through hole was obtained.
Then, the degreased body was fired at 1200 ° C. for 5 hours to obtain a cylindrical sintered body 11 having a cross-sectional diameter of φ5.0 mm and a length of 20.0 mm. The molten metal of tin is poured into the voids of the sintered body 11 thus obtained to form the conductor 12, and finally the electrodes 13 made of Ag—Pd are formed at both ends of the conductor 12. Inductor 1 was manufactured according to the above.

[Embodiment 2] FIG. 3A is a perspective view showing an inductor according to Embodiment 2, and FIG. 3B is a perspective view showing a molded body obtained by press molding of the inductor.

In FIG. 3 (B), a raw material powder prepared in the same manner as in Example 1 was used, and it was composed of an ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 14% and an average molecular weight of 120,000. A coil-shaped core material 22 'having a wire diameter of 0.5 mm was placed in a mold and press-molded to obtain a molded body 21'. Here, also in the molding, similarly to Example 1, the mold was vibrated to increase the powder filling, and then the pressing was performed.

The molded body 21 'is heat-treated at 400 ° C. at a temperature rising rate of 5 ° C./Hr to remove the coil-shaped core material 22' composed of the binder and EVA, and has a coil-shaped through hole. A defatted body (not shown) was obtained. Then, the degreased body was fired at 1200 ° C. for 5 hours to obtain a cross-sectional dimension of 8.
A prismatic sintered body 21 having a length of 0 × 8.0 [mm] and a length of 20.0 mm was obtained. A molten metal of tin is poured into the pores of the sintered body 21 thus obtained to form a conductor 22, and electrodes 23 made of Ag—Pd are formed on both ends of the conductor 22. , Inductor 2 was manufactured.

Although the examples in which the binder and the coil-shaped core material are removed from the molded body by the heat treatment have been described in Examples 1 and 2, they may be removed by another extraction operation.
The coil-shaped core material may be made of the above-mentioned carbon fiber and an organic compound. Further, it is possible to use metal powder as the magnetic material.

[0024]

As described above, according to the present invention, the original characteristics of the magnetic material and the conductor are not impaired,
A small inductor with a coiled conductor built in at a low price
And it becomes possible to manufacture easily. Therefore, the present invention greatly contributes to downsizing of electronic devices,
It will be extremely useful in industry.

[Brief description of drawings]

FIG. 1 is a flowchart showing manufacturing steps of an inductor manufacturing method of the present invention.

2A is a perspective view showing an inductor according to Embodiment 1 of the present invention, and FIG. 2B is a perspective view showing a molded body obtained after press molding of the inductor.

FIG. 3A is a perspective view showing an inductor according to a second embodiment of the present invention. (B) is a perspective view showing a molded body obtained after press molding of the inductor.

[Explanation of symbols]

 1, 2 Inductor 11, 21 Sintered body 12, 22 Conductor 12 ', 22' Coil-shaped core material

Claims (3)

[Claims] 1. A raw material powder obtained by mixing and granulating a powder of metal or ceramics as a magnetic material and a binder, and including a coiled core material made of an organic compound and / or carbon fiber by press molding. A forming step of obtaining a body, a degreasing step of extracting the forming body to remove the binder and the coil-shaped core material to obtain a degreasing body having a through hole, and sintering and sintering the degreasing body A method of manufacturing an inductor, comprising: a sintering step of obtaining a body; and a conductor forming step of providing a conductor inside a through hole of the sintered body. 2. The method for manufacturing an inductor according to claim 1, wherein the degreasing step is performed by heat treatment. 3. An inductor formed by the method for manufacturing an inductor according to claim 1.