KR102104701B1 - Compressed powder core, method of manufacturing the compressed powder core, inductor comprising the compressed powder core and electronic-electric device mounted with the inductor - Google Patents

Abstract

(Task) Providing a powdered core that provides a good inductor with excellent dielectric strength and reduced iron loss for a powdered core containing a powder of a crystalline magnetic material and a powder of an amorphous magnetic material.
(Solution) A pulverized core (1) containing a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, comprising: the crystalline magnetic material to the sum of the content of the powder of the crystalline magnetic material and the content of the powder of the amorphous magnetic material The first mixing ratio, which is the mass ratio of the content of the powder, is 40% by mass or more and 90% by mass or less.

Description

Pressed core, manufacturing method of said pressed core, inductor provided with said pressed core, and electronic / electrical equipment on which the inductor is mounted TECHNICAL FIELD OF THE PRESSURE ELECTRIC DEVICE MOUNTED WITH THE INDUCTOR}

The present invention relates to a compacted core, a method for manufacturing the compacted core, an inductor provided with the compacted core, and an electronic / electric device in which the inductor is mounted. In this specification, "inductor" is a passive element having a core material and a coil including a powder core, and is intended to include the concept of a reactor.

A pressurized circuit such as a hybrid vehicle, a reactor used in an electric power generation or substation facility, and a compacted core used in an inductor such as a transformer or a choke coil can be obtained by compacting a soft magnetic powder. The inductor having such a powder core has low iron loss and excellent insulation withstand voltage (in the present invention, a voltage at which dielectric breakdown occurs when a DC voltage or an AC voltage having a frequency of 60 kHz or less is applied to the inductor (insulation) It is required to have a high breakdown voltage).

In Patent Document 1, in a mixed magnetic powder obtained by mixing an iron-based crystalline alloy magnetic powder and an iron-based amorphous alloy magnetic powder as a means for improving the reduction in insulation resistance in a high-temperature environment, the crystalline alloy magnetic powder and the amorphous alloy A composite magnetic material is disclosed in which the mixing ratio of the magnetic powder is 60 to 90 wt% and 40 to 10 wt%, respectively.

In Patent Document 2, as a means for improving the insulation and corrosion resistance of a powdered magnetic core, in a magnetic core material comprising a mixed magnetic material powder in which an amorphous magnetic alloy powder and a crystalline Fe-Cr-based alloy powder are mixed, and an insulating binder, A composite magnetic material is disclosed in which the mixing ratio of the powder of the amorphous magnetic alloy and the Fe-Cr alloy powder is 10 to 60 wt% of the weight ratio of the Fe-Cr-based alloy powder in the mixed magnetic material powder.

Japanese Patent Application Publication No. 2004-197218 Japanese Patent Publication No. 2007-134381

Patent Literature 1 and Patent Literature 2 both note that when the blending amount of the crystalline alloy powder is increased, the insulation resistance of the compacted core is lowered, and by adjusting the blending ratio of the crystalline alloy magnetic powder and the amorphous alloy magnetic powder in the mixed magnetic powder. , It prevents the fall of insulation resistance. However, in both Patent Document 1 and Patent Document 2, evaluation of the insulation breakdown voltage characteristics of the green compact core was not performed.

Therefore, an object of the present invention is to provide a compacted core containing a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, which provides excellent inductance characteristics and provides a good inductor with reduced iron loss. Another object of the present invention is to provide a method for manufacturing the above-mentioned green compact core, an inductor provided with the green compact core, and an electronic / electric device in which the inductor is mounted.

As a result of examination by the present inventors to solve the above problems, the first mixing ratio which is the mass ratio of the content of the powder of the crystalline magnetic material to the sum of the content of the powder of the crystalline magnetic material and the content of the powder of the amorphous magnetic material By appropriately adjusting, it is possible to improve the dielectric breakdown resistance properties of the green compact core, and in a preferred embodiment, the powder mixture of the crystalline magnetic material contained in the green compact core and the amorphous magnetic material powder is mixed in a range that is estimated. New knowledge has been obtained that nonlinearly improves the dielectric breakdown characteristics of the compacted core and becomes a compacted core that provides a good inductor with reduced iron loss.

The invention completed by this knowledge is as follows.

An aspect of the present invention is a compact core containing a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, wherein the crystalline magnetic material is the sum of the content of the powder of the crystalline magnetic material and the content of the powder of the amorphous magnetic material. The first mixing ratio, which is the mass ratio of the content of the powder, is a compacted core that is 40% by mass or more and 90% by mass or less.

When the first mixing ratio satisfies the above relationship, to improve the dielectric breakdown resistance characteristics of the compacted core nonlinearly, exceeding a range inferred from the crystalline magnetic material or the powder of the amorphous magnetic material, and an inductor It can be used as a compacted core to reduce iron loss.

The said powdered core may have a 1st mixing ratio of 50 mass% or more and 70 mass% or less.

The powder core may have an insulation breakdown value of 120% or more based on the insulation breakdown voltage value of the compacted core containing only the powder of the amorphous magnetic material as a magnetic powder as a reference (100%).

The powder core may have an insulation breakdown value of 110% or more based on the insulation breakdown voltage value of the compacted core containing only the powder of the crystalline magnetic material as a magnetic powder as a reference (100%).

The crystalline magnetic material, Fe-Si-Cr-based alloy, Fe-Ni-based alloy, Fe-Co-based alloy, Fe-V-based alloy, Fe-Al-based alloy, Fe-Si-based alloy, Fe-Si-Al-based It may contain one or more materials selected from the group consisting of alloys, carbonyl iron and pure iron.

The crystalline magnetic material is preferably made of Fe-Si-Cr-based alloy.

The amorphous magnetic material may contain one or more materials selected from the group consisting of Fe-Si-B-based alloys, Fe-P-C-based alloys, and Co-Fe-Si-B-based alloys.

The amorphous magnetic material is preferably made of Fe-P-C-based alloy.

It is preferable that the powder of the crystalline magnetic material is made of a material subjected to insulation treatment. By performing the insulation treatment, it is possible to more stably realize the withstand voltage characteristics of the green powder core, improve the insulation resistance, and reduce iron loss in the high frequency band.

The powdered core may contain a binding component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to other materials contained in the powdered core. In this case, it is preferable that the binding component contains a component based on a resin material.

Another aspect of the present invention is a method of manufacturing the powder core, comprising: pressurizing molding of a mixture containing a powder of the crystalline magnetic material, a powder of the amorphous magnetic material, and a binder component made of the resin material. It is a manufacturing method of a compacted core characterized by including the molding process of obtaining a molding product by. By such a manufacturing method, it is realized to manufacture the green compact core more efficiently.

In the manufacturing method, the molded product obtained by the molding step may be the powder core. Alternatively, a heat treatment step of obtaining the compacted core by heat treatment of heating the molding product obtained by the molding step may be provided.

Another aspect of the present invention is an inductor having a connection terminal connected to each end of the powder core, the coil, and the coil, wherein at least a portion of the powder core is configured to apply current to the coil through the connection terminal. It is an inductor arranged to be located in the induced magnetic field generated by the current when flowing. Such an inductor, on the basis of the excellent properties of the powder core, can achieve both excellent dielectric strength and low loss.

Another aspect of the present invention is an electronic / electric device in which the inductor is mounted, and the inductor is an electronic / electric device connected to the substrate by the connection terminal.

As such an electronic / electric device, a power supply device having a power supply switching circuit, a voltage step-up circuit, a smoothing circuit, or a small portable communication device is exemplified. Since the electronic and electrical equipment according to the present invention includes the inductor, it is easy to cope with high voltage and high frequency.

Since the 1st mixing ratio of the green compact core which concerns on the said invention is adjusted suitably, the insulation breakdown voltage characteristic of such a green compact core can be improved. Further, according to the present invention, there is provided a method for manufacturing the above-mentioned green compact core, an inductor provided with the green compact core, and an electronic / electric device in which the inductor is mounted.

1 is a perspective view conceptually showing a shape of a green compact core according to an embodiment of the present invention.
2 is a view conceptually showing a spray dryer device and its operation used in an example of a method for producing granulated powder.
Fig. 3 is a perspective view conceptually showing the shape of a trojan coil, which is a type of inductor having a compact core according to an embodiment of the present invention.
4 is a perspective view conceptually showing a shape of a coil-buried inductor, which is a type of inductor having a compact core according to an embodiment of the present invention.
5 is a graph showing the dependence of the dielectric breakdown voltage on the first mixing ratio in Example 1;
6 is a graph showing the dependence of the dielectric breakdown voltage on the first mixing ratio in Example 2;
7 is a graph showing the dependence of the dielectric breakdown voltage on the first mixing ratio in Examples 1 and 2;
Fig. 8 is a graph showing the dielectric breakdown voltage ratio in each of the first mixing ratios based on a single powder of amorphous magnetic material in Examples 1 and 2.
9 is a graph showing the dielectric breakdown voltage ratio in each of the first mixing ratios based on the powder alone of the crystalline magnetic material in Examples 1 and 2.
10 is a graph showing the dependence of the insulation resistance on the first mixing ratio in Example 1;
11 is a graph showing the dependence of the core density on the first mixing ratio in Example 1;
12 is a graph showing the dependence of permeability on the first mixing ratio in Example 1;
13 is a graph showing the dependence of the insulation resistance on the first mixing ratio in Example 2;
14 is a graph showing the dependence of the core density on the first mixing ratio in Example 2;
15 is a graph showing the dependence of permeability on the first mixing ratio in Example 2;

Hereinafter, embodiments of the present invention will be described in detail.

1. Pressed core

The compacted core 1 according to an embodiment of the present invention shown in Fig. 1 is a ring-shaped trojan core having an outer appearance and contains a powder of a crystalline magnetic material and a powder of an amorphous magnetic material. The compacted core 1 according to the present embodiment is produced by a manufacturing method including a molding process including pressure-molding a mixture containing these powders. As a non-limiting example, the compacted core 1 according to the present embodiment includes other materials (of the same material) in which the powder of the crystalline magnetic material and the powder of the amorphous magnetic material are contained in the compacted core 1. It may contain a heterogeneous material).

(1) Powder of crystalline magnetic material

The crystalline magnetic material that gives the powder of the crystalline magnetic material contained in the compacted core 1 according to one embodiment of the present invention is crystalline (which is clear enough to specify the material type by general X-ray diffraction measurement). As long as it satisfies that a diffraction spectrum having a peak is obtained) and a ferromagnetic material, particularly a soft magnetic material, the specific type is not limited. As a specific example of the crystalline magnetic material, Fe-Si-Cr-based alloy, Fe-Ni-based alloy, Fe-Co-based alloy, Fe-V-based alloy, Fe-Al-based alloy, Fe-Si-based alloy, Fe-Si- And Al-based alloys, carbonyl iron, and pure iron. The crystalline magnetic material may be composed of one kind of material or may be composed of a plurality of kinds of materials. The crystalline magnetic material that provides the powder of the crystalline magnetic material is preferably one or two or more materials selected from the group consisting of the above materials, and among these, it is preferable to contain a Fe-Si-Cr-based alloy, Fe It is more preferably made of -Si-Cr-based alloy. Since the Fe-Si-Cr-based alloy is a material capable of relatively low iron loss (Pcv) among the crystalline magnetic materials, the content of the powder of the crystalline magnetic material and the content of the amorphous magnetic material in the compact core 1 Even if the mass ratio of the content of the powder of the crystalline magnetic material with respect to the sum of (also referred to as "first mixing ratio" in this specification) is increased, the iron loss (Pcv) of the inductor having the compact core 1 is unlikely to increase. The content of Si and the content of Cr in the Fe-Si-Cr-based alloy is not limited. As a non-limiting example, the content of Si is about 2 to 7 mass%, and the content of Cr is about 2 to 7 mass%.

The shape of the powder of the crystalline magnetic material contained in the compacted core 1 according to one embodiment of the present invention is not limited. The shape of the powder may be spherical or non-spherical. In the case of a non-spherical shape, a shape having shape anisotropy such as a scale shape, an elliptical shape, a droplet shape, or a needle shape may be used, or an irregular shape having no special shape anisotropy may be used. As an example of the amorphous powder, there may be mentioned a case in which a plurality of spherical powders are bonded to each other or to be partially buried in another powder. Such an amorphous powder is likely to be observed in carbonyl iron.

The shape of the powder may be a shape obtained in the step of manufacturing the powder, or may be a shape obtained by secondary processing of the produced powder. As the former shape, a spherical shape, an elliptical spherical shape, a droplet shape, a needle shape, etc. are illustrated, and as the latter shape, a scale shape is illustrated.

The particle size of the powder of the crystalline magnetic material contained in the compacted core 1 according to one embodiment of the present invention is not limited. In the powder of the crystalline magnetic material, in the particle size distribution on a volume basis, the particle size in which the cumulative particle size distribution from the small diameter side becomes 50% (also referred to herein as "medium glasses") (D ₅₀ C) is 15 µm or less It may be desirable. Since the powder of the crystalline magnetic material is soft compared to the powder of the amorphous magnetic material, there is a high possibility that the powder of the crystalline magnetic material is deformed inside the compact core 1. For this reason, the influence of the size of the particle size on the characteristics of the compacted core 1 is relatively low. The median diameter (D ₅₀ A) of the crystalline magnetic material powder is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 2 μm or less.

The content of the powder of the crystalline magnetic material in the compacted core 1 is an amount such that the first mixing ratio becomes 40% by mass or more and 90% by mass or less. When the 1st mixing ratio is 40 mass% or more and 90 mass% or less, the insulation breakdown voltage characteristic of the compacted core 1 improves compared with the case which consists only of an amorphous magnetic material. It is considered that the improvement in the dielectric breakdown resistance is because the dielectric breakdown energy is dispersed as the powder core 1 contains a powder of a crystalline magnetic material in the above range. From the viewpoint of stably improving the withstand voltage characteristics of the green compact core 1, the first mixing ratio is more preferably 45 mass% or more and 85 mass% or less, and particularly preferably 50 mass% or more and 80 mass% or less. By setting the first mixing ratio within the above range, for example, a compacted core 1 having good dielectric strength characteristics can be produced using an amorphous magnetic material having a D ₅₀ A of about 3 μm or more and about 20 μm.

The dielectric breakdown voltage value of the green compact core 1 is preferably 1.2 times or more, more preferably 1.25 times or more, and preferably 1.3 times or more of the dielectric breakdown voltage value of the green compact core containing only the powder of the amorphous magnetic material as the magnetic powder. . Here, the term "magnetic powder" refers to the powder of the crystalline magnetic material contained in the compact core 1 and the powder of the amorphous magnetic material. "A compacted core containing only the powder of the amorphous magnetic material as a magnetic powder" refers to a compacted core manufactured under the same components and conditions, except that all of the crystalline magnetic materials in the compacted core are replaced with an amorphous magnetic material.

It is preferable that at least a part of the powder of the crystalline magnetic material is made of a material subjected to surface insulation treatment, and it is more preferable that the powder of a crystalline magnetic material is made of a material subjected to surface insulation treatment. When the surface insulation treatment is performed on the powder of the crystalline magnetic material, a tendency to improve the insulation resistance of the compacted core 1 is observed. The type of surface insulation treatment applied to the powder of the crystalline magnetic material is not limited. Phosphoric acid treatment, phosphate treatment, oxidation treatment, etc. are illustrated.

(2) Powder of amorphous magnetic material

The amorphous magnetic material that imparts the powder of the amorphous magnetic material contained in the compacted core 1 according to the embodiment of the present invention is amorphous (which is clear enough to specify a material type by general X-ray diffraction measurement). As long as the diffraction spectrum having a peak is not obtained) and a ferromagnetic material, particularly a soft magnetic material, are satisfied, the specific type is not limited. Specific examples of the amorphous magnetic material include Fe-Si-B-based alloys, Fe-P-C-based alloys, and Co-Fe-Si-B-based alloys. The amorphous magnetic material may be composed of one kind of material or may be composed of a plurality of kinds of materials. The magnetic material constituting the powder of the amorphous magnetic material is preferably one or two or more materials selected from the group consisting of the above materials, and among these, it is preferable to contain a Fe-PC alloy, and a Fe-PC system It is more preferably made of an alloy.

As a specific example of the Fe-PC-based alloy, the composition formula is represented by Fe _{100 atomic% -abcxyzt} Ni _a Sn _b Cr _c P _x C _y B _z Si _t , and 0 atomic% ≤ a ≤ 10 atomic%, 0 atomic% ≤ b ≤ 3 atomic%, 0 atomic% ≤ c ≤ 6 atomic%, 6.8 atomic% ≤ x ≤ 13 atomic%, 2.2 atomic% ≤ y ≤ 13 atomic%, 0 atomic% ≤ z ≤ 9 atomic%, 0 atomic% ≤ t And an Fe-based amorphous alloy having a content of ≤ 7 atomic%. In the above composition formula, Ni, Sn, Cr, B and Si are optional additive elements.

It is preferable that the addition amount a of Ni is 0 atomic% or more and 6 atomic% or less, and more preferably 0 atomic% or more and 4 atomic% or less. The addition amount b of Sn is preferably 0 atomic% or more and 2 atomic% or less, and may be added in a range of 1 atomic% or more and 2 atomic% or less. Cr addition amount c is preferably 0 atomic% or more and 2 atomic% or less, and more preferably 1 atomic% or more and 2 atomic% or less. In some cases, the amount of P added x is preferably 8.8 atomic% or more. It is preferable to make the addition amount y of C into 4 atomic% or more and 10 atomic% or less, and in some cases it is desirable to make it into 5.8 atomic% or more and 8.8 atomic% or less. The addition amount z of B is preferably 0 atomic% or more and 6 atomic% or less, and more preferably 0 atomic% or more and 2 atomic% or less. The addition amount t of Si is preferably 0 atomic% or more and 6 atomic% or less, and more preferably 0 atomic% or more and 2 atomic% or less.

The shape of the powder of the amorphous magnetic material contained in the compacted core 1 according to the embodiment of the present invention is not limited. The type of the shape of the powder is the same as that of the powder of the crystalline magnetic material, and therefore the description is omitted. In relation to the manufacturing method, it may be easy to make the amorphous magnetic material into a spherical or elliptical spherical shape. Moreover, as a general theory, since the amorphous magnetic material is harder than the crystalline magnetic material, there are cases in which it is desirable to make the crystalline magnetic material non-spherical and easily deform during pressure molding.

The shape of the powder of the amorphous magnetic material contained in the powder core 1 according to one embodiment of the present invention may be a shape obtained in the step of manufacturing the powder, or a shape obtained by secondary processing the produced powder. A spherical shape, an elliptical spherical shape, a needle shape, etc. are illustrated as an former shape, and a scale shape is illustrated as the latter shape.

As for the particle diameter of the powder of the amorphous magnetic material contained in the powder core 1 according to one embodiment of the present invention, it is sometimes desirable that the median diameter (D ₅₀ A) of the powder of the amorphous magnetic material is 50 µm or less. When the median diameter (D ₅₀ A) of the powder of the amorphous magnetic material is 50 µm or less, it is sometimes easy to reduce the iron loss Pcv while improving the insulation resistance of the compacted core 1. From the viewpoint of more stably realizing reducing the iron loss (Pcv) while improving the insulation resistance of the compacted core 1, it is sometimes desirable that the median diameter (D ₅₀ A) of the powder of the amorphous magnetic material is 20 μm or less. , 10 µm or less, more preferably 7 µm or less, and sometimes 5 µm or less are particularly preferable.

(3) Binder component

The compacted core 1 may contain a binding component that binds the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to other materials contained in the compacted core 1. The binding component fixes the powder of the crystalline magnetic material and the powder of the amorphous magnetic material contained in the compact core 1 according to the present embodiment (in this specification, these powders may be collectively referred to as "magnetic powder"). The composition is not limited as long as it is a material contributing to the prescribing. As the material constituting the binding component, organic materials such as resin materials and thermal decomposition residues of the resin materials (in the present specification, these are collectively referred to as "components based on resin materials"), inorganic materials, and the like are exemplified. . As a resin material, acrylic resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, etc. are illustrated. As the binding component made of an inorganic material, glass-based materials such as water glass are exemplified. The binding component may be composed of one type of material, or may be composed of a plurality of materials. The binding component may be a mixture of an organic material and an inorganic material.

As a binding component, an insulating material is usually used. Thereby, the insulating property as the compacted core 1 can be improved.

2. Manufacturing method of the powder core

Although the manufacturing method of the compacted core 1 which concerns on one Embodiment of this invention is not specifically limited, When the manufacturing method demonstrated next is employ | adopted, it is realized to manufacture the compacted core 1 more efficiently.

The manufacturing method of the green compact core 1 which concerns on one Embodiment of this invention may be provided with the molding process demonstrated next, and may be provided with the heat processing process.

(1) Molding process

First, a mixture containing a magnetic powder and a component that imparts a binding component in the compacted core 1 is prepared. The component that gives the binding component (also referred to as "binder component" in this specification) may be the binding component itself, or may be a material different from the binding component. As a specific example of the latter, the case where the binder component is a resin material and the binder component is a thermal decomposition residue is exemplified.

A molding product can be obtained by a molding treatment including press molding of this mixture. The pressing condition is not limited, and is appropriately determined based on the composition of the binder component and the like. For example, when the binder component is made of a thermosetting resin, it is preferable to heat with pressure and advance the curing reaction of the resin in the mold. On the other hand, in the case of compression molding, although the pressing force is high, heating does not become a necessary condition, and pressure is applied for a short time.

Hereinafter, the case where the mixture is granulated powder and compression molding is performed will be described in detail. Since the granulated powder has excellent handling properties, it is possible to improve the workability of a compression molding process having a short molding time and excellent productivity.

(1-1) granulated powder

The granulated powder contains a magnetic powder and a binder component. The content of the binder component in the granulated powder is not particularly limited. When such content is excessively low, it becomes difficult for the binder component to hold the magnetic powder. Moreover, in the case where the content of the binder component is excessively low, in the compacted core 1 obtained through the heat treatment step, the binder component composed of the thermal decomposition residue of the binder component becomes difficult to insulate a plurality of magnetic powders from different ones. . On the other hand, when the content of the binder component is excessively high, the content of the binder component contained in the compacted core 1 obtained through the heat treatment step tends to increase. When the content of the binding component in the green compact core 1 becomes high, the magnetic properties of the green compact core 1 tends to deteriorate. Therefore, it is preferable that the content of the binder component in the granulated powder is 0.5 mass% or more and 5.0 mass% or less with respect to the whole granulated powder. From the viewpoint of more stably reducing the possibility that the magnetic properties of the compacted core 1 are lowered, it is preferable that the content of the binder component in the granulated powder is 1.0 mass% or more and 3.5 mass% or less with respect to the whole granulated powder. It is more preferable to make it into an amount which becomes 1.2 mass% or more and 3.0 mass% or less.

The granulated powder may contain materials other than the magnetic powder and the binder component. As such a material, a lubricant, a silane coupling agent, an insulating filler, etc. are illustrated. In the case of containing a lubricant, the kind is not particularly limited. It may be an organic lubricant or an inorganic lubricant. Specific examples of the organic lubricant include metal soaps such as zinc stearate and aluminum stearate. It is considered that such an organic lubricant is vaporized in a heat treatment step and hardly remains in the compacted core 1.

The manufacturing method of granulated powder is not specifically limited. The component to which the granulated powder is applied is kneaded as it is, or the obtained kneaded product may be pulverized by a known method to obtain a granulated powder, and a slurry formed by adding a dispersion medium (water may be mentioned as an example) to the component is prepared. Then, the slurry may be dried and pulverized to obtain granulated powder. After grinding, sieving or classification may be performed to control the particle size distribution of the granulated powder.

As an example of a method for obtaining granulated powder from the slurry, a method using a spray dryer is exemplified. As shown in FIG. 2, a rotor 201 is formed in the spray dryer device 200, and the slurry S is injected from the top of the spray dryer device 200 toward the rotor 201. The rotor 201 rotates according to a predetermined number of revolutions, and sprays the slurry S as a droplet by centrifugal force in a chamber inside the spray dryer device 200. In addition, hot air is introduced into the chamber inside the spray dryer device 200, thereby volatilizing the dispersion medium (water) contained in the droplet-like slurry S while maintaining the droplet shape. As a result, granulated powder P is formed from the slurry S. The granulated powder P is recovered from the lower portion of the spray dryer device 200. Each parameter such as the number of revolutions of the rotor 201, the temperature of the hot air introduced into the spray dryer device 200, and the temperature under the chamber may be appropriately set. As a specific example of the setting range of these parameters, the rotational speed of the rotor 201 is 4000 to 8000 rpm, the hot air temperature introduced into the spray dryer device 200 is 130 to 170 ° C, and the temperature at the bottom of the chamber is 80 to 90 ° C. Can be mentioned. Also, the atmosphere in the chamber and its pressure may be appropriately set. As an example, it is mentioned that the inside of the chamber is an air (air) atmosphere, and the pressure is 2 mmH ₂ O (approximately 0.02 kPa) at a differential pressure from atmospheric pressure. You may further control the particle size distribution of the obtained granulated powder (P) by sieving or the like.

(1-2) Pressurization conditions

The pressing conditions in compression molding are not particularly limited. It may be appropriately set in consideration of the composition of the granulated powder, the shape of the molded product, and the like. When the pressing force when compression-molding the granulated powder is excessively low, the mechanical strength of the molded article decreases. For this reason, the problem that the mechanical strength of the compacted core 1 obtained from the molded article which falls in the handleability of a molded article falls may easily arise. In addition, the magnetic properties of the powder core 1 may be lowered or the insulation may be lowered. On the other hand, when the pressing force for compression-molding the granulated powder is excessively high, it becomes difficult to manufacture a molding die that can withstand the pressure. From the viewpoint of more stably reducing the possibility that the compression pressurizing process adversely affects the mechanical properties or magnetic properties of the compacted core 1, and easily mass-producing industrially, the pressing force in compression molding the granulated powder is , It is preferably 0.3 ㎬ or more and 2 2 or less, more preferably 0.5 ㎬ or more and 2 ㎬ or less, and particularly preferably 0.8 ㎬ or more and 2 ㎬ or less.

In compression molding, pressurization may be performed while heating, or pressurization may be performed at room temperature.

(2) Heat treatment process

The molded product obtained by the molding process may be the compacted core 1 according to the present embodiment, or the molded product may be subjected to a heat treatment process to obtain the compacted core 1 as described below.

In the heat treatment step, by heating the molding product obtained by the molding step, magnetic properties are adjusted by correcting the distance between the magnetic powders, and the magnetic properties are adjusted by alleviating the deformation imparted to the magnetic powder in the forming step. , To obtain a compacted core (1).

Since the heat treatment step is aimed at adjusting the magnetic properties of the compacted core 1 as described above, the heat treatment conditions such as the heat treatment temperature are set such that the magnetic properties of the compacted core 1 are best. As an example of a method for setting the heat treatment conditions, it is possible to change the heating temperature of the molding product, and to make other conditions constant, such as a heating rate and a holding time at the heating temperature.

The evaluation criteria of the magnetic properties of the compacted core 1 when setting the heat treatment conditions are not particularly limited. The iron loss (Pcv) of the compacted core 1 is mentioned as a specific example of an evaluation item. In this case, it is sufficient to set the heating temperature of the molding product so that the iron loss Pcv of the compacted core 1 is the lowest. The measurement conditions of the iron loss Pcv are appropriately set, and as an example, conditions are set to a frequency of 100 kHz and an effective maximum magnetic flux density (Bm) of 100 mT.

The atmosphere during heat treatment is not particularly limited. In the case of an oxidizing atmosphere, it is preferable to perform heat treatment in an inert atmosphere such as nitrogen or argon or a reducing atmosphere such as hydrogen because the possibility of excessive thermal decomposition of the binder component or the possibility of oxidation of the magnetic powder increases. .

3. Inductors, electronic and electrical equipment

The inductor according to one embodiment of the present invention includes the compact core 1 according to the embodiment of the present invention, a coil, and a connection terminal connected to each end of the coil. Here, at least a portion of the powder core 1 is arranged to be located in an induction magnetic field generated by this current when current flows through the coil through the connection terminal. Since the inductor according to one embodiment of the present invention includes the compact core 1 according to the above-described embodiment of the present invention, it is excellent in dielectric breakdown resistance characteristics and it is difficult to increase iron loss even at high frequencies. Therefore, it can be made smaller than the inductor related to the prior art.

As an example of such an inductor, the trojan coil 10 shown in FIG. 3 is mentioned. The trojan coil 10 is provided with a coil 2a formed by winding a covering conductive wire 2 on a ring-shaped compact core (Troyder core) 1. In the portion of the conductive wire located between the coil 2a composed of the wound coated conductive wire 2 and the ends 2b and 2c of the coated conductive wire 2, the ends 2d and 2e of the coil 2a are Can be defined. As described above, in the inductor according to the present embodiment, the member constituting the coil and the member constituting the connection terminal may be composed of the same member.

As another example of the inductor according to the embodiment of the present invention, a coil-buried inductor 20 shown in Fig. 4 is exemplified. The coil-embedded inductor 20 can be formed into a small chip shape having a width and length of several millimeters, is provided with a compact core 21 having a box-like shape, and has a conductive wire 22 covered therein. The coil portion 22c is buried. The ends 22a and 22b of the coated conductive wire 22 are located on the surface of the compacted core 21 and are exposed. Part of the surface of the compacted core 21 is covered by connecting ends 23a and 23b that are electrically independent of each other. The connecting end 23a is electrically connected to the end 22a of the covered conductive line 22, and the connecting end 23b is electrically connected to the end 22b of the covered conductive line 22. In the coil buried inductor 20 shown in Fig. 4, the end portion 22a of the covered conductive wire 22 is covered by the connecting end 23a, and the end portion 22b of the covered conductive wire 22 is connected to the connecting end 23b. Covered by.

The method of embedding the coiled portion 22c of the covered conductive wire 22 into the compacted core 21 is not limited. The member on which the coated conductive wire 22 is wound may be placed in a mold, and a mixture (assembled powder) containing magnetic powder may be supplied into the mold to perform pressure molding. Alternatively, a plurality of members obtained by preliminarily molding a mixture (granulated powder) containing a magnetic powder are prepared, these members are combined, and then the coated conductive wire 22 is placed in the voids formed to obtain an assembly, The granulated body may be pressure-molded. The material of the coated conductive wire 22 including the coil portion 22c is not limited. For example, what is made of copper alloy is mentioned. The coil portion 22c may be an edge-wise coil. The material of the connecting ends 23a and 23b is not limited. From the viewpoint of excellent productivity, it is sometimes desirable to provide a metallization layer formed from a conductive paste such as a silver paste and a plating layer formed on the metallization layer. The material forming the plating layer is not limited. Examples of metal elements contained in the material include copper, aluminum, zinc, nickel, iron, and tin.

The electronic / electrical device according to one embodiment of the present invention is an electronic / electrical device in which the inductor according to the embodiment of the present invention is mounted, and is connected to a substrate by the connection terminal. Since the inductor according to the embodiment of the present invention is mounted in the electronic / electric device according to the embodiment of the present invention, the function of the inductor may be reduced even if a high voltage or high frequency signal is applied to the device. However, problems caused by heat generation are unlikely to occur, and it is easy to downsize the device.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents falling within the technical scope of the present invention.

Example

Hereinafter, the present invention will be described more specifically by examples and the like, but the scope of the present invention is not limited to these examples and the like.

(Example 1)

(1) Preparation of Fe-based amorphous alloy powder

Fe _balance N _{5 to 7 atomic%} Cr _{2 to 4 atomic%} P _{10 to 13 atomic%} C _{5 to 6 atomic%} B _{2 to 4 atomic%} Weigh the raw materials to have a composition, and use the water _atomization method to obtain amorphous magnetic properties. A powder of material (amorphous powder) was prepared. The particle size distribution of the powder of the obtained amorphous magnetic material was measured by volume distribution using a "micro track particle size distribution measuring device MT3300EX" manufactured by Nikkiso. In the particle size distribution on a volume basis, the particle size (median diameter) (D ₅₀ A) in which the cumulative particle size distribution from the small diameter side becomes 50% was 5 µm.

Further, as a powder of the crystalline magnetic material, the Fe-Si-Cr-based alloy, specifically, the Si content is 6 to 7% by mass, the Cr content is 3 to 4% by mass, and the remainder is composed of Fe and unavoidable impurities. A powder made of an alloy and having a median diameter (D ₅₀ C) of 2 μm was prepared.

(2) Preparation of granulated powder

The powder of the amorphous magnetic material and the powder of the crystalline magnetic material were mixed to a first mixing ratio shown in Table 1 to obtain a magnetic powder. 97.2 parts by mass of the magnetic powder, 2 to 3 parts by mass of the insulating binder made of an acrylic resin or phenol resin, and 0 to 0.5 parts by mass of a lubricant made of zinc stearate were mixed with water as a solvent to obtain a slurry.

The obtained slurry was granulated under the conditions described above using the spray dryer apparatus 200 shown in FIG. 2 to obtain granulated powder.

(3) Compression molding

The obtained granulated powder was filled into a mold, and pressure-molded with a surface pressure of 0.5 to 1.5 MPa to obtain a molded body having a ring shape having an outer diameter of 20 mm × an inner diameter of 12 mm × a thickness of 3 mm.

(4) Heat treatment

The obtained molded body was placed in a furnace in a nitrogen stream atmosphere, and the temperature in the furnace was heated from room temperature (23 ° C.) to an optimum core heat treatment temperature of 200 to 400 ° C. at a heating rate of 10 ° C./min. It maintained for 1 hour, and after that, heat-processed to cool to room temperature in a furnace, and obtained the troydal core which consists of a compacted core.

A troder core having a different first mixing ratio shown in Table 1 was prepared, and the core density, insulation resistance, dielectric breakdown voltage, magnetic permeability and iron loss (Pcv) were measured by the following measurement method.

(Test Example 1) Measurement of dielectric breakdown voltage

As a measuring device, a "TOS5051A" breakdown pressure tester manufactured by Kikusui was used to sandwich the trojan core as a sample with a parallel plate electrode, and an applied voltage was applied with AC (50 Hz). The voltage to break the insulation was determined as the dielectric breakdown voltage.

The insulation breakdown voltage values of Examples 1-2 to Examples 1-8 measured as described above are based on the insulation breakdown voltage values of the Troider cores of Example 1-1 containing only the powder of the amorphous magnetic material as the magnetic powder. (100%) based on the dielectric breakdown voltage ratio (based on 100% amorphous) and the dielectric breakdown value of the Troider core of Example 1-8 containing only a powder of a crystalline magnetic material as a magnetic powder (100%) The dielectric breakdown voltage ratio (based on crystalline 100%) in the case was determined.

(Test Example 2) Measurement of insulation resistance

As a measuring device, the former Agilent (now Keysight) "4339B" high-resistance meter was used to measure by a two-terminal method at an applied voltage of 20 V.

(Test Example 3) Measurement of core density (ρ)

The dimensions and weight of the Troid cores prepared in Example 1 were measured, and the density (ρ) (unit: g / cc) of each Troid core was calculated from these values.

(Test Example 4) Measurement of permeability

100 ㎑ of an impedance analyzer ("4192A" manufactured by HP) was used for the Troid coil obtained by winding the copper wire coated on the Troid core prepared in Example 1 by winding 40 times on the primary side and 10 times on the secondary side, respectively. The initial permeability (μ 0) was measured.

(Test Example 5) Measurement of iron loss (Pcv)

The Troid coil obtained by winding the coated copper wire on the Troid core prepared in Example 1 by winding the copper wire 15 times on the primary side and 10 times on the secondary side, using a BH analyzer ("SY-8217" manufactured by Iwasaki Communications Co., Ltd.), was effective. Iron loss (Pcv) (unit: kW / m 3) was measured at a measurement frequency of 2 MHz under the condition that the maximum magnetic flux density (Bm) was 15 mT.

Table 1 shows the results measured using the methods of Test Examples 1 to 5 described above.

5 is a graph showing the dependence of the dielectric breakdown voltage for Example 1 on the first mixing ratio. As shown in the graph of the dielectric breakdown voltage of the copper diagram, in Example 1, by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, the dielectric breakdown characteristics were improved compared to the case where each magnetic powder was used alone. . That is, by mixing the different magnetic powders, an effect of synergistically increasing the dielectric breakdown value of the powder core was obtained. In Example 1, the insulation withstand value rapidly increases from around 30 mass% to 40 mass% in the first mixing ratio, and in the range of 40 mass% to 70 mass%, the insulation breakdown voltage ratio becomes 120% or more, and 50 mass% to In the range of 70 mass%, the dielectric breakdown ratio became 130% or more, and the value of the dielectric breakdown ratio based on the powder alone of the amorphous magnetic material of Example 1-1 as a reference (100%) improved by 30% or more.

(Example 2)

The magnetic powder used in Example 1 is a powder having a powder core of an amorphous magnetic material, a surface treatment of a powder of a crystalline magnetic material, and a magnetic powder having a different particle diameter. Got.

Specifically, as an amorphous magnetic material powder, a Fe-based amorphous alloy powder having a composition having the same composition as in Example 1 and a median diameter (D50A) of 15 μm was prepared. In addition, the powder of the amorphous magnetic material used in Example 2 was produced by an atomizing method in which gas atomizing and water atomizing were continuously performed.

As a powder of a crystalline magnetic material, Fe-Si-Cr-based alloys, specifically, Si content is 6 to 7 mass%, Cr content is 3 to 4 mass%, and the balance is made of Fe and inevitable impurities. Made, a powder having a median diameter (D50C) of 4 μm was prepared. As the powder of the crystalline magnetic material, a phosphate-based surface insulation treatment was used.

The pressing force of the press molding was 0.5 to 1.5 MPa, and in the heat treatment, it was heated at 200 to 400 ° C in a nitrogen atmosphere for 1 hour.

The Troider cores with different first mixing ratios shown in Table 2 below were prepared, and the dielectric breakdown voltage, insulation resistance, core density, permeability and iron loss (Pcv) were measured.

(Test Examples 1 to 5)

Measurement of insulation breakdown voltage, measurement of insulation resistance, measurement of core density (ρ), measurement of permeability and measurement of iron loss (Pcv) were carried out in the same manner as in Example 1.

The dielectric breakdown voltage ratio (based on 100% amorphous) and the powder of the crystalline magnetic material as the magnetic powder only when the dielectric breakdown voltage value of the Troider core of Example 2-1 containing only the powder of the amorphous magnetic material is based on (100%) The dielectric breakdown voltage ratio (based on crystalline 100%) was determined when the insulation breakdown voltage value of the containing Trojan core of Example 2-7 was used as a reference (100%).

In addition to the initial magnetic permeability (μ 0), a DC current was superimposed on the troder coil under the condition of 100 ,, and the specific magnetic permeability (μ5500) when the applied DC magnetic field was 5500 A / m was also measured. Table 2 shows the measurement results.

6 is a graph showing the dependence of the dielectric breakdown voltage on Example 2 on the first mixing ratio. As shown in the graph of the dielectric breakdown voltage in Fig. 6, in Example 2, as in Example 1, by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, the dielectric breakdown voltage was compared with the case where each powder was used alone. The properties were improved, and a synergistic effect was recognized. In Example 2, since the first mixing ratio was about 40% by mass, the dielectric breakdown value was higher than that of the amorphous magnetic material powder, and the dielectric breakdown ratio was 180% or more in the range of 70% by mass to 90% by mass. The value of the dielectric breakdown voltage ratio based on the powder simple substance of the amorphous magnetic material of 6 as a reference (100%) was improved by 80% or more.

7 is a graph showing the dependence of the dielectric breakdown voltage on the first mixing ratio in Examples 1 and 2; From the results of the drawings, it was found that by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, a powder core having a higher dielectric breakdown voltage was obtained than when each powder was used alone. In other words, Fig. 7 is more than expected based on the mixing ratio of the powder of the crystalline magnetic material and the powder of the amorphous magnetic material contained in the powder core, that is, by a synergistic effect exceeding the simple causticity, the dielectric breakdown voltage It is shown that a powder core having excellent properties was obtained.

Fig. 8 is a graph showing the dielectric breakdown ratio in each of the first mixing ratios based on the powder of the amorphous magnetic material in Example 1 and Example 2, and Fig. 9 is Example 1 And in Example 2, a graph showing the dielectric breakdown ratio in each of the first mixing ratios based on a single powder of crystalline material.

From the results of Figs. 5 to 9, the effect of improving the value of the dielectric breakdown voltage was adjusted by adjusting the median diameter (D ₅₀ A) of the amorphous magnetic material appropriately, and the first mixing ratio was 40 mass% or more and 90 mass%. By setting it within the following range, it appears stably. Moreover, by making the 1st mixing ratio into 50-70 mass%, even if the median diameter (D ₅₀ A) of an amorphous magnetic material is large or small, the insulation withstand voltage characteristic of a piezoelectric core can be improved. In addition, when the first mixing ratio (50 to 70 mass%) as described above from FIG. 9 is used, the value of the insulation withstand pressure ratio when the powder core containing only crystalline material powder as a magnetic powder is used as a reference (100%) is 110%. It can be seen that the above or a powder core having 125% or more can be obtained.

10 to 12 are graphs showing the dependence of the insulation resistance, the core density, and the magnetic permeability on the first mixing ratio for Example 1 in this order.

13 to 15 are graphs showing the dependence of insulation breakdown voltage, insulation resistance, core density, and permeability on the first mixing ratio for Example 2 in this order.

As shown in Table 1 and Table 2, and FIGS. 5 to 15, the excellent compacted core obtained by mixing the powder of the crystalline magnetic material with the powder of the amorphous magnetic material, in addition to the improvement of the dielectric breakdown resistance, almost reduced iron loss (Pcv) It was possible to increase the dielectric breakdown voltage without increasing, thereby providing a good inductor.

ADVANTAGE OF THE INVENTION According to this invention, the powder core which gives the favorable inductor with excellent insulation withstand voltage characteristics and reduced iron loss is obtained, and the degree of the goodness is the powder of the crystalline magnetic material and the amorphous magnetic material contained in the powder core. It was confirmed by this example that the degree exceeded the expectations based on the mixing ratio.

The inductor provided with the powder core of the present invention can be preferably used as a component of a booster circuit such as a hybrid vehicle, a component of a power generation / substation facility, a component such as a transformer or choke coil, and the like.

1: Compaction core (Troder core)
10: Trojan coil
2: Covered conductive wire
2a: coil
2b, 2c: ends of the coated conductive wire 2
2d, 2e: end of coil 2a
20: coil buried inductor
21: powder core
22: coated conductive wire
22a, 22b: end
23a, 23b: connecting end
22c: coil part
200: spray dryer device
201: rotor
S: Slurry
P: granulated powder

Claims (16)

A compact core comprising a powder of a crystalline magnetic material and a powder of an amorphous magnetic material,
The first mixing ratio, which is the mass ratio of the content of the powder of the crystalline magnetic material to the sum of the content of the powder of the crystalline magnetic material and the content of the powder of the amorphous magnetic material, is 50 mass% or more and 70 mass% or less,
The amorphous magnetic material is made of Fe-PC-based alloy, a compacted core. delete According to claim 1,
The green powder core has a dielectric breakdown value of 120% or more based on the insulation breakdown voltage value of a green compact core containing only the powder of the amorphous magnetic material as a magnetic powder as a reference (100%). According to claim 1,
The powdered core has a dielectric breakdown value of 110% or more based on a dielectric breakdown value of a compacted core containing only the powder of the crystalline magnetic material as a magnetic powder as a reference (100%). According to claim 1,
The crystalline magnetic material, Fe-Si-Cr-based alloy, Fe-Ni-based alloy, Fe-Co-based alloy, Fe-V-based alloy, Fe-Al-based alloy, Fe-Si-based alloy, Fe-Si-Al-based A compacted core containing one or more materials selected from the group consisting of alloys, carbonyl iron and pure iron. According to claim 1,
The crystalline magnetic material is made of Fe-Si-Cr-based alloy, a compacted core. delete delete According to claim 1,
The powder of the crystalline magnetic material is made of a material subjected to an insulation treatment, and a compacted core. According to claim 1,
A powder core comprising a binding component for binding the powder of the crystalline magnetic material and the powder of the amorphous magnetic material to other materials contained in the powder core. The method of claim 10,
The said binding component contains a component based on a resin material, and a compacted core. A method for producing a green compact core according to claim 11, wherein the molding product is subjected to a molding process by press molding of a mixture containing a powder of the crystalline magnetic material, a powder of the amorphous magnetic material, and a binder component made of the resin material. A manufacturing method of a compacted core comprising a molding step to be obtained. The method of claim 12,
A method for producing a green compact core, wherein the green product obtained by the molding process is the green compact core. The method of claim 12,
And a heat treatment step of obtaining the powder core by heat treatment to heat the molding product obtained by the molding step. An inductor having a compaction core according to claim 1, a coil, and a connection terminal connected to each end of the coil, wherein at least a portion of the compaction core is applied to the current when a current flows through the connection terminal through the coil. An inductor, arranged to be located within the induced magnetic field generated by the magnetic field. An electronic / electric device in which the inductor according to claim 15 is mounted, wherein the inductor is connected to a substrate by the connection terminal.

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