JPH04373106A - Inductor and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To miniaturize electronic equipment by a method wherein a coiled cavity part having both ends thereof exposed outward and formed along a cylindrical surface as well as a conductor part formed along the cavity part are provided inside a magnetic powder sintered body having the cylindrical surface. CONSTITUTION:A mixture for molding step is produced by kneading and then crushing or granulating magnetic powder and an organic binder. Next, the mixture is formed to have a cylindrical surface so that a coiled core material comprising the filament of carbon fiber or an organic compound may be internally located while exposing both ends of the core material outward. Next, a sintered body internally having the coiled cavity part 2 with both ends thereof passed through outward can be formed by removing the binder and the core material from a molded body to be baked later. Finally, a conductor layer 2 is formed inside the cavity part 2. Through these procedures, an electronic equipment can be miniaturized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor made of a magnetic material and a coiled conductor, and a method for manufacturing the same, and more particularly to a miniaturized inductor and a method for manufacturing the same.

0002

2. Description of the Related Art The structure of an inductance element used for noise prevention in electronic equipment, etc. is the simplest and commonly used one in which a conductor is wound around a toroidal magnetic core. However, in recent years, the trend of miniaturization of electronic devices has become even more remarkable, and the demand for miniaturization of inductance elements is also increasing. However, there are many cases where it is not possible to respond. In addition, miniaturization requires improving the efficiency of the element, and an effective way to achieve this is to embed the coil in the magnetic core to prevent the magnetic flux generated by the coil from leaking outside. It is. From this point of view, by alternately stacking conductors and sheets made of magnetic powder so that some of the conductors have contact points, we can obtain a powder compact of magnetic material with a built-in conductor coil. Inductors manufactured by sintering have been put into practical use.

0003

[Problems to be Solved by the Invention] However, the inductor obtained by the above-mentioned method of laminating magnetic sheets and conductors has a complicated manufacturing process, which not only increases the manufacturing cost, but also requires the sintering process to remove the conductor. Since the components constituting the material and the magnetic material diffuse alternately, the characteristics of each material were not fully expressed in terms of properties.

[0004] Therefore, the technical problem of the present invention is to
It is an object of the present invention to provide an inductor that can fully exhibit the original characteristics of magnetic materials and conductors, and a method for manufacturing the same.

[0005]

[Means for Solving the Problems] According to the present invention, a coil-shaped cavity is formed inside a magnetic powder sintered body having a cylindrical surface, both ends of which are exposed to the outside, and formed along the cylindrical surface. An inductor is obtained that includes a hole and a conductor layer provided along the hole. According to the present invention, there is a mixture production step in which a mixture for molding is obtained by mixing and kneading magnetic powder and a binder whose main component is an organic compound, and then pulverizing or granulating the mixture; A molding step of molding the mixture into a cylindrical surface by incorporating a coiled core material made of filaments and exposing both ends of the core material to the outside, and removing a binder from the molded body. A sintering step in which a sintered body is obtained by removing the core material and sintering to obtain a sintered body having a coil-shaped hole inside with both ends penetrating to the outside, and a sintering step in which a conductor is placed inside the hole. There is obtained a method for manufacturing an inductor characterized by comprising a conductor forming step of forming a layer. Here, the magnetic powder material used in the present invention is not particularly limited as long as it can be basically sintered, but examples of metal materials include permalloy, and examples of ceramic materials include Ni- A typical example is Zn-based ferrite. The core material in the present invention includes various organic substances, carbon fibers, and the like. However, since it is difficult to remove carbon fiber by methods other than combustion, it is better to avoid using it in the case of magnetic materials whose properties deteriorate due to oxidation. In addition, methods for forming a conductor layer inside the pores formed inside the sintered body include various plating methods, casting of molten metal, chemical vapor phase decomposition method, physical vapor phase decomposition method, etc. Examples include, but are not limited to.

[0006]

Embodiments Below, embodiments of the present invention will be described with reference to the drawings. 100 parts by weight of Ni-Zn ferrite powder with an average particle size of 1 μm, 6 parts by weight of paraffin with a melting point of 63°C, and ethylene with a vinyl acetate content of 14% and an average molecular weight of 150,000. 3 parts by weight of vinyl acetate copolymer and 1 part by weight of high-density polyethylene having an average molecular weight of about 210,000 were each weighed out and kneaded in a pressure kneader for about 1 hour. This mixture was made into pellets with a diameter of 4 mm and a length of approximately 5 mm using an extruder equipped with a rotating blade to obtain a raw material for molding. This raw material was injection molded using a ring-shaped mold into which a coil had been inserted so that both ends were exposed to the outside, to obtain a cylindrical molded body 10 with a built-in coil 1 as shown in FIG. . The coil 1 used here is made of a nylon 6 filament with a diameter of 0.5 mm, an outer diameter of 3 mm, and a number of turns of 20 turns. The dimensions of the mold are outer diameter: φ20mm x inner diameter: 10mm.
×Thickness: 5 mm. Next, this molded body 10 is charged into a degreasing furnace, and from room temperature to 180°C is heated at 50°C/Hr and 1
10°C/Hr. from 80°C. The temperature was raised to 400°C at a heating rate of 5 hours. Degreasing was performed under the condition that the material was maintained, and the nylon 6 forming the internal coil 1 was removed together with the binder. This degreased body was heated at 1,200°C for 3 hours. It was sintered and the nylon 6 portion was removed. A sintered body having the same shape as the molded body 10 containing coil-shaped holes except that it was reduced in size was obtained. A plating solution was passed through the pores of the sintered body thus obtained, and a Ni conductor layer having a thickness of approximately 10 μm was formed by electroless plating to form an inductor as a conductor coil.

[0007]

[Effects of the Invention] As explained in detail above, according to the present invention, manufacturing of a small inductor with a built-in coil is possible.
This method is possible at a lower cost than conventional methods, greatly contributes to the miniaturization of electronic devices, and is extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a molded article according to an example of the present invention.

[Explanation of symbols]

1 Coil 2 Hole part 10 Molded object

Claims (2)

[Claims] Claim 1: Inside a magnetic powder sintered body having a cylindrical surface, both ends are exposed to the outside, and a coil-shaped cavity is formed along the cylindrical surface, and a coil-shaped cavity is formed along the cavity. An inductor comprising a conductor layer provided with a conductor layer. [Claim 2] A mixture production step in which a mixture for molding is obtained by mixing and kneading magnetic powder and a binder whose main component is an organic compound, and then pulverizing or granulating the mixture; A molding step of molding the mixture to have a cylindrical surface by incorporating a coiled core material made of filaments and exposing both ends of the core material to the outside, and removing a binder and a binder from the molded body. A sintering process in which a core material is removed and sintered to obtain a sintered body having a coil-shaped hole inside with both ends penetrating to the outside, and a conductor layer is formed inside the hole. 1. A method for manufacturing an inductor, comprising: a conductor forming step of forming a conductor.