JPH06310334A - Inductor and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain an annular or rod-like inductor by a method wherein a sintered magnetic material, consisting of soft magnetic material and having a groove provided in advance for formation of a winding without using a winding machine for formation of the annular or rod-like inductor around the magnetic path of an annular or rod-like magnetic material, is formed and a conductor is formed in the groove. CONSTITUTION:After kneading the mixture, consisting of oxide magnetic powder having a high relative permeability and the binder mainly composed of an organic high molecular compound, the mixture is injection-molded in a mold in which grooves 2, a terminal point 3 and a lead hole 4 are formed. A metal layer conductor, having excellent electricity conducting characteristics, is filled in the groove of a degreased and sintered annular soft magnetic body 1, and the mixture of an annular inductor or oxide magnetic powder and an organic high molecular compound are kneaded. The mixture is semicylindrically extrusion-molded, a groove is provided around it, a good electric conductive material is filled in the groove, and a rod-like inductor is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a soft magnetic sintered body having continuous grooves on its peripheral surface in advance, and a good electric conductor (hereinafter referred to as a conductor) in a groove formed so as to be wound around a magnetic body. The present invention relates to an annular inductor and a rod-shaped inductor in which windings are filled by filling (hereinafter, referred to as)) and a manufacturing method thereof, and particularly to an annular and rod-shaped inductor which can be inexpensively constructed and a manufacturing method thereof.

[0002]

2. Description of the Related Art An annular inductor has a relative magnetic permeability due to a demagnetizing field generated by a magnetic body forming a magnetic path by a magnetic field generated in the magnetic path when a current flows through a winding wound around the annular magnetic path. It has been used in a wide range because it can obtain high relative magnetic permeability characteristics without deterioration of However, due to the rapid miniaturization of electronic devices and the demand for miniaturization of the inductance element (inductor), it is difficult to wind the annular inductor as it becomes smaller. Therefore, the winding is wound around a rod-shaped magnetic core. It is used as a small inductor. The oxide magnetic material of the magnetic core used in the conventional annular inductor and small rod-shaped inductor is generally manufactured by the powder metallurgy method. That is, a mixture of magnetic powder and a small amount of binder is compression-molded to obtain a ring-shaped or rod-shaped molded body, which is then sintered. The soft magnetic body just after sintering is wound. As an inductor.

However, it is difficult to automate the winding because the shape of the magnetic core is annular or rod-shaped, a complicated machine is required for the automation of the winding, and it takes time because of its structure and causes a cost increase. Was there. Further, since the oxide magnetic material of the magnetic core is formed by compression molding, it is limited to a simple shape, and it is difficult to provide fine grooves.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a groove for burying a conductor forming a winding in a sintered body of a magnetic material is provided in advance around the magnetic path of the sintered body, and the conductor is buried in the groove. In order to provide a small and inexpensive inductor and a manufacturing method thereof, which is a ring-shaped inductor or a small rod-shaped inductor without using a winding machine.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a soft material for compacting an annular or rod-shaped oxide magnetic material or metal magnetic fine powder in which a groove for a conductor forming a winding is provided around a soft magnetic material. A magnetic material is used to embed a conductor in a winding forming groove for forming a winding to form a winding, thereby obtaining an annular inductor or a rod-shaped inductor.

The present invention is a method for producing an annular or rod-shaped oxide magnetic material having a spiral groove for forming a winding, which comprises using an oxide magnetic powder and a binder containing an organic polymer compound as a main component. After kneading the mixture, it is injection-molded in a mold, degreased and sintered, and an annular or rod-shaped oxide magnetic material in which a conductor is embedded in a groove formed in a spiral shape on the outer periphery of the sintered body. Is a method for manufacturing an annular or rod-shaped inductor.

The present invention uses an annular or rod-shaped oxide magnetic material in which a groove for a conductor forming a winding is formed by injection molding, and the groove portion is immersed in a molten liquid of the conductor to form a molten metal. A method for manufacturing an annular or rod-shaped inductor, which comprises filling and cooling to form a conductor.

According to the present invention, an annular or rod-shaped oxide magnetic material in which a groove for a conductor forming a winding is formed by injection molding is used, and the groove portion is filled with metal powder and melted or sintered. A method for manufacturing an annular or rod-shaped inductor, comprising forming a winding conductor.

In the present invention, as ceramics and metal powders of magnetic materials having high relative magnetic permeability characteristics, Ni-Zn ferrite and Mn-Zn ferrite are used as ceramics, and Sendust dust core is used as magnetic metal powders. As an example, a mixture of these may be used, and the present invention is not limited thereto, and the magnetic material forming the inductor may be appropriately selected depending on the used frequency band of the formed inductor. As the binder mixed with the ceramic powder and the metal powder, various polyolefins, copolymers, waxes and the like can be used.
It is appropriately selected in consideration of surface properties and the like.

That is, the present invention is characterized in that a metal good electric conductor is integrally formed in a groove formed around a magnetic path of an annular or rod-shaped magnetic material sintered body having a high relative magnetic permeability characteristic. Is an inductor.

After kneading a mixture of at least one kind of soft magnetic ceramic powder or soft magnetic metal powder having a high relative magnetic permeability property and a binder containing an organic polymer compound as a main component, a central axis of an annular molded body is provided around the kneaded material. Injection molded in a mold that forms a groove that circulates in the center, a terminal portion, and a lead hole,
A method for manufacturing an annular inductor, comprising degreasing and sintering to form an annular magnetic material sintered body having a groove for a conductor, and filling the groove with a good electrical conductor. .

[0012] A rod-shaped inductor characterized in that a magnetic material sintered body having a spiral groove on the outer periphery of a rod-shaped body having a circular cross section and an electric conductor is formed in the spiral groove. Is.

At least one kind of soft magnetic ceramic powder or soft magnetic metal powder and a binder are mixed and kneaded, and the mixture is granulated or pulverized, and extruded into a rod-like body while forming a spiral groove on the outer peripheral portion, The rod-shaped inductor is characterized in that a good electric conductor is formed in the spiral groove by degreasing and sintering.

After kneading a mixture of at least one kind of soft magnetic ceramic powder or soft magnetic metal powder having a high relative magnetic permeability property and a binder containing an organic polymer compound as a main component, a ring-shaped central axis is centered on the periphery. Injection molding in a mold that forms a groove that circles around, a terminal portion, and a lead hole,
2. A magnetic material sintered body having a groove for a conductor is formed by degreasing and sintering, and the groove is filled with electrically conductive metal powder and melted or sintered. A method for manufacturing an inductor according to claim 2, claim 3, or claim 4.

At least one of soft magnetic ceramic powder or soft magnetic metal powder and a binder are mixed and kneaded, and the mixture is granulated or pulverized to form a spiral groove on the extruded rod-shaped surface, and degreasing and baking. The obtained sintered body is dipped in a molten bath of a good electric conductor, the periphery is covered with a conductor layer, and then the metal coating layer excluding the groove is removed to form an outer peripheral portion of the sintered body. The method of manufacturing an inductor according to claim 1, 2, 3, or 4, further comprising a good electrical conductor formed in a spiral shape.

[0016]

According to the present invention, an oxide magnetic material obtained by adding and kneading a binder is used to form a ring-shaped inductor by winding a winding around a ring-shaped magnetic core or a rod-shaped soft magnetic material to form a rod-shaped inductor. Powder or soft magnetic metal powder is formed in advance around the soft magnetic body by a powder injection molding method in which a conductor for forming a winding is embedded. The raw material powder is heated to about 10 to 20% by weight. A degreasing process in which a binder made of a plastic resin, a plasticizer, etc. is added, and after kneading, injection molding is performed to obtain a ring-shaped or rod-shaped molded body having grooves around the magnetic path, and then the binder is removed by an operation such as heating. And sintered to obtain a soft magnetic metal powder core having a required shape and winding grooves, or a ceramic sintered body.

In the molding of the magnetic core by the injection molding, the magnetic core shape is produced by compressing and molding the conventional magnetic powder by applying a high pressure, whereas it is difficult to form a magnetic core without using a high pressure. There is an advantage that the product can be obtained with high dimensional accuracy and mass productivity. Therefore, by using the manufacturing method of the present invention,
It is possible to obtain an annular or rod-shaped oxide magnetic body having a groove of a winding conductor, or a metal magnetic body, which is difficult to obtain by a usual powder metallurgy method.

For the annular or rod-shaped oxide magnetic material or metal magnetic material obtained by the above method, the groove portion is passed through a molten metal bath to fill the groove portion with metal and to cool the winding. An annular inductor is obtained by forming the conductor forming the. In this case, the upper and lower surfaces and the inner and outer circumferences may be polished as needed. As a method of forming the conductor, the groove may be filled with metal powder and melted or sintered to fill the groove with the conductor forming the winding.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

[0020]

Embodiment 1 FIGS. 1 and 2 show an annular inductor of the present invention. FIG. 1 shows a groove 2 for forming a winding and a terminal portion in an annular soft magnetic body 1 of an oxide magnetic material having a high relative permeability characteristic. 3 and a lead hole 4 for attaching a lead wire. FIG. 2 shows one annular soft magnetic body 1 and two grooves 2 forming a common mode choke coil in which the same number of turns is wound in the same phase. FIG. 3 is a perspective view of a soft magnetic body formed of an annular oxide magnetic material having a groove for a conductor used in the present invention, in which a strip, a terminal portion 3, and a lead hole 4 for attaching a lead wire are formed. As shown in FIG. 1, the annular oxide magnetic material has a semi-circular groove 2 having a radius of 0.5 mm for forming a conductor in an annular magnetic body and is used for forming a conductor to be connected to a lead wire (not shown). The terminal portion 3 of the groove is provided.

The oxide magnetic material powder has a particle size distribution of 8
N with an average particle size of about 1.2 μm in the range of μm to 0.3 μm
An i-Zn ferrite pre-calcined powder was prepared, and A was used as a binder for 84 wt% of the Ni-Zn ferrite pre-calcined powder.
7% by weight of low-density polyethylene having a melt flow rate by STM of 3.0 g / 10 minutes and a density of 0.93 gr / cm ³ , 7% by weight of paraffin wax having an average molecular weight of 400, and 2% by weight of dioctyl phthalate were used as oxide magnetic material powders. Was added to and kneaded at 100 ° C. and crushed to obtain a raw material for injection molding.

Using this injection molding raw material, an injection molding die for obtaining a molding of an oxide magnetic material having a groove for conductor formation shown in FIG. 1 is injection molded at 130 ° C. to form a molding. Obtained.

Next, this molded body was heated up to 500 ° C. at a temperature rising rate of 5 ° C./hour for degreasing. The obtained degreased body was sintered at 1200 ° C. in the air for about 2 hours to obtain a ring-shaped oxide magnetic body having a groove for forming a conductor as shown in FIGS. Using this, molten solder is poured into the conductor forming groove 2 and cooled, and then the solder protruding from the groove is attached to the upper and lower surfaces,
An annular inductor was obtained by polishing the inner and outer peripheries. In this example, the Ni-Zn ferrite powder 84
The total amount of the binders added is 16% by weight with respect to the weight%. However, when the binder component ratio to the Ni-Zn ferrite is the best, the low density polyethylene 7: paraffin wax 7: dioctyl phthalate 2 is used. It is necessary to add it in an amount of 7.5 to 22% by weight, preferably 9.2 to 18.7% by weight. However, the component ratio of the binder varies depending on the ratio of the amount of the binder added to the magnetic powder, and the ratio of the binder to be added is not limited to the ratio of low density polyethylene 7: paraffin wax 7: dioctyl phthalate 2.

[0024]

[Embodiment 2] The depth of 0.4 mm is set in the groove 2 of the annular oxide magnetic body having the same conductor forming groove 2 as that shown in FIGS. 1 and 2 used in Embodiment 1. A paste in which solder powder was dispersed was filled, and then heated and melted to form a conductor, and a ring inductor was obtained.

[0025]

[Third Embodiment] The groove 2 of the annular oxide magnetic material having the same conductor forming groove as that shown in FIGS. 1 and 2 used in the first embodiment is set to have a depth of 0.4 mm. A paste in which copper-aluminum alloy powder was dispersed was filled, and the mixture was baked at 800 ° C. to form a conductor and obtain an annular inductor.

[0026]

Example 4 100 parts by weight of Ni-Zn ferrite powder having the same characteristics as in Example 1 was used, and the average molecular weight was 140,00.
3 parts by weight of polybutyl methacrylate of 0, 3 parts by weight of ethylene-vinyl acetate copolymer having a vinyl acetate content of 14% and an average molecular weight of 120,000, and 4 parts by weight of paraffin wax having a melting point of 63 ° C. were weighed. Using a pressure kneader, they were mixed in the atmosphere at 130 ° C. for 1 hour. As shown in FIG. 4, the obtained mixture was provided with a cutter 6 near the mold 5 at the outlet of the molded body, which revolves around the molded body on a plane perpendicular to the extrusion direction and whose circular blade rotates. By extrusion molding with a molding machine, a molded body 7 having a series of spiral grooves 2 in the outer peripheral portion shown in FIG. 3 was obtained. This molded body was degreased and sintered at 1200 ° C. for 5 hours. Then, the obtained sintered body was dipped in a bath in which silver was melted to form a conductor coating layer on the surface. Further, the rod-shaped magnetic core 8 obtained by this sintering is rotated around both end faces perpendicular to the longitudinal direction, and the conductor 9 in the groove portion is rotated.
The coating layer on the surface was removed by cutting so as to leave only this, and cut into a predetermined length to obtain a rod-shaped inductor. In this example, the amount of the binder added to the Ni-Zn ferrite powder was 1.5 to 6 parts by weight of polybutyl methacrylate, preferably 2.4 to 4.5 parts by weight, ethylene-vinyl acetate. The copolymer is 1.5 to 6 parts by weight, preferably 2.4 to 4.5 parts by weight, and the paraffin wax is 2 to 8 parts by weight, preferably 3.2 to 6 parts by weight. It is necessary to

[0027]

Example 5 The mixture is extruded into a rod-shaped body having a circular cross section and cut into a predetermined length. After cooling the molded body, as shown in FIG. 5, a series of spiral grooves 2 are formed on the surface of the molded body through the tap 11 that rotates the molded body 10. Then, in the same manner as in Example 4, the conductor coating layer was provided on the surface by immersing it in a silver molten bath, and the conductor coating layer on the surface was removed by cutting so as to leave only the spiral groove portion to obtain a rod-shaped inductor.

In the present embodiment, Ni-Zn ferrite was used for explanation, but it is naturally applicable to other oxide magnetic materials such as Mn-Zn ferrite and Sendust dust core having high material resistivity. Is.

[0029]

As described above, according to the present invention,
A ring-shaped inductor that is easier and cheaper to manufacture than conventional ones can be obtained, and a small-sized rod-shaped inductor integrated with a conductor can be used as the inductor and the manufacturing method thereof according to the present invention without deteriorating the characteristics. It has an effect that a small inductor can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an annular inductor having one conductor according to the present invention.

FIG. 2 is an external perspective view showing one annular inductor in which two conductors according to the present invention are formed in the same phase.

FIG. 3 is an external perspective view showing a rod-shaped inductor according to the present invention.

FIG. 4 is an external perspective view showing a method for manufacturing a rod-shaped inductor according to the present invention.

FIG. 5 is an external perspective view showing another manufacturing method of the rod-shaped inductor according to the present invention.

[Explanation of symbols]

 1 Annular soft magnetic material 2 Groove (winding) 3 Terminal part 4 Lead hole 5 Mold 6 Cutter 7 Molded body 8 Rod-shaped magnetic core 9 Conductor 10 Molded body 11 Tap

Claims (6)

[Claims] 1. An inductor characterized in that a metal good electric conductor is integrally formed in a groove formed around a magnetic path of an annular or rod-shaped magnetic material sintered body having a high relative magnetic permeability characteristic. . 2. After kneading a mixture of at least one of soft magnetic ceramic powder or soft magnetic metal powder having high relative magnetic permeability characteristics and a binder containing an organic polymer as a main component, the center of an annular molded body is surrounded. The annular magnetic material sintered body having a groove for a conductor is formed by injection molding in a mold that forms a groove that circulates around an axis, a terminal portion and a lead hole, and degreasing and sintering the groove. A method for manufacturing an annular inductor, characterized in that a good electrical conductor is filled in and formed. 3. A rod-shaped body having a rod-shaped body having a circular cross section and having a spiral groove on an outer peripheral portion of the rod-shaped body, and a good electric conductor formed in the spiral groove. Inductor. 4. A mixture obtained by mixing and kneading at least one kind of soft magnetic ceramic powder or soft magnetic metal powder and a binder, granulating or crushing the mixture, and extruding into a rod-like body while forming a spiral groove in the outer peripheral portion. The rod-shaped inductor is characterized in that a good electrical conductor is formed in the spiral groove by degreasing and sintering. 5. A mixture of at least one of soft magnetic ceramic powder or soft magnetic metal powder having a high relative magnetic permeability characteristic and a binder containing an organic polymer compound as a main component is kneaded, and then an annular central axis is provided around the mixture. Of the magnetic material sintered body having a groove for a conductor by injection molding, degreasing and sintering in a mold that forms a groove, a terminal portion and a lead hole that circulate around The method for manufacturing an inductor according to claim 1, claim 2, claim 3, or claim 4, characterized in that the conductive metal powder is filled and melted or sintered. 6. A mixture obtained by mixing and kneading at least one of soft magnetic ceramic powder or soft magnetic metal powder and a binder, granulating or crushing the mixture, forming a spiral groove on an extruded rod-shaped surface, and degreasing. The sintered body was sintered, and the obtained sintered body was immersed in a molten bath of a good electric conductor to coat the periphery with a conductor layer, and then remove the metal coating layer excluding the groove to remove the sintered body. The method of manufacturing an inductor according to claim 1, 2, 3, or 4, further comprising a good electrical conductor formed in a spiral shape on an outer peripheral portion.