Manufacturing method of powder magnetic core

Abstract

The method for manufacturing a magnetic material includes a mixture production step of producing a mixture containing an organic solvent, metal magnetic powder, a resin material, and an organometallic soap, and a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, the resin material, and the organometallic soap are integrated.

Description

[Technical field]

[0001] The present disclosure relates to a method for producing a powder magnetic core. By law Regarding. [Background technology]

[0002] Conventionally, oxide magnetic materials such as ferrite and metal magnetic materials have been used as magnetic materials for the magnetic cores of inductors and transformers. Magnetic cores using these magnetic materials include, for example, dust cores made by compressing metal powder. Dust cores have a high saturation magnetic flux density and are advantageous for miniaturizing components such as inductors and transformers. In addition, dust cores can be molded using a die, so there is a high degree of freedom in the shape of the magnetic core, and even complex shapes can be manufactured with high precision using a simple process, so their usefulness has been attracting attention (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a magnetic material mainly composed of iron (Fe) and silicon (Si) as a magnetic material constituting a powder magnetic core, and a powder magnetic core using the magnetic material. In Patent Document 1, an insulating coating is formed on the surface of a metal magnetic powder mainly composed of Fe and Si. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-146315 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to obtain insulation and adhesion between the metal magnetic powders, the powder core is produced by adding an insulating and adhesive resin material to the metal magnetic powder, drying the mixture, and then pressure molding the mixture. However, since the resin material has a high molecular weight, the molecules may become entangled, making it impossible to highly pack the metal magnetic powder in the powder core. This causes a problem that the magnetic properties of the powder core cannot be improved.

[0006] In view of the above-mentioned problems, the present invention provides a method for obtaining high magnetic properties. Manufacturing method of powder magnetic core The purpose is to provide the following: [Means for solving the problem]

[0008] A method for producing a powder magnetic core according to one embodiment of the present disclosure includes: Contains acrylic resin A mixture containing a resin material and an organometallic soap is produced. the mixture is heated to remove the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, the resin material, and the organometallic soap are integrated; a first heat treatment step is performed to high-pressure press the magnetic material obtained in the first heat treatment step to obtain a green body; and a second heat treatment step is performed to heat the green body obtained in the first molding step, wherein the temperature in the second heat treatment step is 600°C to 1000°C, and the filling rate of the metal magnetic powder in the dust core is 82% or more and 83% or less. A method for producing a powder magnetic core according to one embodiment of the present disclosure includes: Contains acrylic resin The method includes a mixture production step of producing a mixture containing a resin material and an organometallic soap, a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, the resin material, and the organometallic soap are integrated, a first molding step of high-pressure pressing the magnetic material obtained in the first heat treatment step to obtain a molded body, and a second heat treatment step of heating the molded body obtained in the first molding step, wherein the temperature of the second heat treatment step is 800°C to 1000°C. A method for producing a powder magnetic core according to one embodiment of the present disclosure includes: Contains acrylic resin The method includes a mixture producing step of producing a mixture containing a resin material and an organometallic soap, a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to produce a magnetic material in which the metal magnetic powder, the resin material and the organometallic soap are integrated, a first molding step of high-pressure pressing the magnetic material produced in the first heat treatment step to produce a green body, and a second heat treatment step of heating the green body produced in the first molding step, wherein the molding pressure in the first molding step is 10 ton / cm. 2 The temperature of the second heat treatment step is 600°C to 1000°C. Effect of the Invention

[0013] According to the present disclosure, in order to obtain high magnetic properties, Manufacturing method of powder magnetic core etc. can be provided. [Brief description of the drawings]

[0014] [Figure 1A] FIG. 1A is a schematic perspective view showing a configuration of a coil component according to a first embodiment. [Figure 1B] FIG. 1B is an exploded perspective view showing the configuration of the coil component according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the configuration of the magnetic material according to the first embodiment. [Diagram 3] FIG. 3 is a flowchart showing the manufacturing process of the magnetic material and the coil component according to the first embodiment. [Figure 4] FIG. 4 is a flowchart showing a granulated powder manufacturing process according to the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing the granulated powder according to the first embodiment, which is granulated and dried and then powdered. As shown in FIG. [Figure 6] FIG. 6 is a flowchart showing a core manufacturing process according to the first embodiment. [Figure 7]FIG. 7 is a diagram illustrating the granulated powder according to the first embodiment, which is a schematic diagram of the granulated powder before pressure molding. [Figure 8] FIG. 8 is a flowchart showing a coil assembly process according to the first embodiment. [Figure 9A] FIG. 9A is a diagram showing the additive material contained in the magnetic material of Example 1 of Embodiment 1, the filling rate of the metal magnetic powder contained in the magnetic core, and the initial permeability of the magnetic core. [Figure 9B] FIG. 9B is a graph showing the additive material contained in the magnetic material of Example 1 of Embodiment 1, the density of the metal magnetic powder in the magnetic core, and the initial permeability of the magnetic core. [Figure 10] FIG. 10 is a diagram showing the additive material contained in the magnetic material of Example 2 of the first embodiment, the filling rate of the metal magnetic powder contained in the magnetic core, and the initial permeability of the magnetic core. [Figure 11A] FIG. 11A is a diagram showing the additive material contained in the magnetic material of Example 3 of Embodiment 1, the filling rate of the metal magnetic powder contained in the magnetic core, and the initial permeability of the magnetic core. [Figure 11B] FIG. 11B is a graph showing the additive material contained in the magnetic material of Example 3 of Embodiment 1, the density of the metal magnetic powder in the magnetic core, and the initial permeability of the magnetic core. [Figure 12A] FIG. 12A is a schematic perspective view showing a configuration of a coil component according to the second embodiment. [Figure 12B] FIG. 12B is a cross-sectional view showing the configuration of the coil component according to the second embodiment. [Figure 13] FIG. 13 is a flowchart showing a manufacturing process of the coil component according to the second embodiment. [Figure 14] FIG. 14 is a flowchart showing a core manufacturing process and a coil assembly process according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiment will be specifically described with reference to the drawings.

[0016] Note that the embodiments described below each show a specific example of the present disclosure. The numerical values, shapes, materials, components, component arrangement positions, connection forms, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in an independent claim showing a top concept are described as optional components.

[0017] (Embodiment 1) [1-1. Configuration of coil components and magnetic core] Coil component 1 according to the present embodiment is composed of a magnetic core (dust core) made of a magnetic material, and a coil portion disposed inside the magnetic core.

[0018] Fig. 1A is a schematic perspective view showing the configuration of a coil component 1 according to the present embodiment. Fig. 1B is an exploded perspective view showing the configuration of the coil component 1 according to the present embodiment. Fig. 2 is a cross-sectional view showing the configuration of a magnetic material according to the present embodiment.

[0019] 1A and 1B, the coil device 1 includes two split magnetic cores 12, a conductor 13, and two coil supports 14. The two split magnetic cores 12 form a magnetic core, and the conductor 13 and the two coil supports 14 form a coil portion.

[0020] The split magnetic core 12 includes a base 12a and a cylindrical core portion 12b formed on one surface of the base 12a. In addition, two opposing sides of the four sides constituting the base 12a are formed with wall portions 12c standing upright from the edge of the base 12a. The core portion 12b and the wall portion 12c are at the same height from the one surface of the base 12a. Each of the two split magnetic cores 12 is a powder magnetic core formed by pressure-molding a magnetic material into a predetermined shape.

[0021] The two split magnetic cores 12 are arranged so that their cores 12b and wall portions 12c abut against each other. At this time, the conductor 13 is arranged so as to surround the periphery of the core 12b. The conductor 13 is incorporated into the split magnetic cores 12 via the coil support 14.

[0022] 1B, each of the two coil supports 14 has an annular base portion 14a and a cylindrical portion 14b. The core portion 12b of the split magnetic core 12 is disposed inside the cylindrical portion 14b, and the conductor 13 is disposed on the outer periphery of the cylindrical portion 14b.

[0023] The magnetic material constituting the split magnetic cores 12 is, for example, an Fe--Si based metallic magnetic material, which is an alloy containing Fe and Si as main components.

[0024] 2, in the split magnetic core 12, a plurality of metal magnetic powder particles 17 are pressure-molded, and an insulating material 18 is formed on the surface of each metal magnetic powder particle 17. The insulating materials 18 covering the surfaces of adjacent metal magnetic powder particles 17 are bonded to each other. In other words, the insulating materials 18 are disposed between each metal magnetic powder particle 17, and each metal magnetic powder particle 17 is insulated from each other.

[0025] The Fe-Si-based metal magnetic powder 17 is a metal soft magnetic powder mainly composed of Fe and Si, or a metal soft magnetic powder mainly composed of Fe, Si, and Al. The metal magnetic powder 17 may contain unavoidable impurities other than Fe, Si, and Al. In the metal magnetic powder 17 of this embodiment, Si is used to improve the soft magnetic properties. The addition of Si can reduce the magnetic anisotropy and magnetostriction constant of the metal magnetic powder 17, and can also increase the electrical resistance and reduce eddy current loss.

[0026] The method for producing the metal magnetic powder 17 according to this embodiment is not particularly limited, and various atomizing methods and various pulverizing methods can be used.

[0027] The average particle size of the metal magnetic powder 17 according to the present embodiment is preferably 1 μm or more and 100 μm or less. If the average particle size is less than 1 μm, the molding density is low and the magnetic permeability is reduced. If the average particle size is greater than 100 μm, the eddy current loss at high frequencies is large. More preferably, the average particle size of the metal magnetic powder 17 is 50 μm or less. The average particle size of the metal magnetic powder is determined by a laser diffraction particle size distribution measurement method. For example, the particle size of a measured particle that shows the same diffraction and scattered light pattern as a sphere with a diameter of 10 μm is 10 μm regardless of its shape. Then, the particle sizes are counted from the smallest to the largest, and the particle size when the cumulative total reaches 50% of the total is taken as the average particle size.

[0028] The insulating material 18 contains, for example, at least one of Ti, Zr, and Al. The insulating material 18 is formed so as to cover the surfaces of the metal magnetic powder 17, and adjacent metal magnetic powder particles 17 are insulated by the insulating material 18.

[0029] [1-2. Manufacturing methods for coil components and magnetic materials] The manufacturing method of the magnetic material and the coil component according to the present embodiment will be described below. Fig. 3 is a flow chart showing the manufacturing process of the magnetic material and the coil component 1 according to the present embodiment.

[0030] As shown in FIG. 3, the manufacturing process of coil component 1 according to this embodiment includes a granulated powder manufacturing step (step S10), a core manufacturing step (step S20), and a coil assembly step (step S30). In the granulated powder manufacturing step, a magnetic material constituting the magnetic core described above is produced. In the core manufacturing step, split magnetic cores 12 are formed by molding the magnetic material. In the coil assembly step, split magnetic cores 12, conductor 13, and coil support 14 described above are assembled to complete coil component 1. Each step will be described in detail below.

[0031] Fig. 4 is a flow chart showing a granulated powder manufacturing process according to the present embodiment. As shown in Fig. 4, in the granulated powder manufacturing process, first, raw materials for producing a magnetic material are prepared (step S11). As raw materials for the magnetic material, metal magnetic powder 17, a first resin material having insulating properties, a second resin material having adhesive properties, an organic metal soap, and an organic solvent are prepared. In the following, both the first resin material and the second resin material may be collectively referred to as "resin material".

[0032] The metal magnetic powder 17 is made of a magnetic material powder mainly composed of Fe. For example, the metal magnetic powder 17 is made of an alloy of Fe and Si, sendust, permalloy, or the like. When an alloy of Fe and Si is used, the content of Fe and Si may be adjusted. The particle size of the metal magnetic powder 17 is, for example, 20 μm.

[0033] The first resin material is a material that becomes the insulating material 18 after the split magnetic core (powder magnetic core) 12 after pressure molding is heat treated. The first resin material is, for example, a material such as a silicone resin, a phenolic resin, or an epoxy resin. For example, silicon contained in silicone resin remains between adjacent metal magnetic powder particles even after heat treatment is performed on the split magnetic core 12, and is therefore suitable for ensuring insulation between the metal magnetic powder particles.

[0034] The second resin material is a material that acts as a binding material (binder). For example, acrylic resin, silicone resin, butyral resin, or other materials are used for the second resin material. For example, acrylic resin is suitable for suppressing springback after pressure molding and ensuring the shape retention of split magnetic core 12 after pressure molding. The second resin material is a material that is removed by subjecting split magnetic core 12 after pressure molding to heat treatment.

[0035] The first and second resin materials used in the present embodiment may be either a thermosetting resin or a thermoplastic resin. If the first and second resin materials are thermosetting resins, they are liquid at room temperature.

[0036] The organometallic soap is a material for softening the resin material, and includes, for example, a material containing a metal stearate such as zinc stearate, magnesium stearate, or calcium stearate.

[0037] The chemical formula for zinc stearate is Zn(C 17 H 35 The chemical formula for magnesium stearate is Mg(C 17 H 35 The chemical formula of calcium stearate is Ca(C 17 H 35 COO)2. Zinc stearate, magnesium stearate, and calcium stearate each have a long-chain hydrocarbon, so they are compatible with resin materials. Therefore, by adding an organometallic soap containing metal stearate in the granulated powder manufacturing process, the resin material contained in the granulated powder can be softened and the granulated powder can be plasticized (made soft and easily deformed).

[0038] In this embodiment, the weight ratio of the organometallic soap contained in the magnetic material is 0.05% by weight or more and 0.5% by weight or less with respect to the metal magnetic powder 17. Also, the weight ratio of the organometallic soap contained in the magnetic material is 5% by weight or more and 40% by weight or less with respect to the resin material. These will be described in detail in the examples.

[0039] The organic solvent is a solvent for facilitating mixing and dispersing the metal magnetic powder 17, the resin material, and the organometallic soap. For example, toluene, xylene, ethanol, or the like is used as the organic solvent.

[0040] Next, the metal magnetic powder 17, the resin material, the organometallic soap, and the organic solvent are kneaded and dispersed (step S12). This produces a mixture containing the organic solvent, the metal magnetic powder, the resin material, and the organometallic soap. The kneading and dispersion are performed by placing the weighed metal magnetic powder 17, the resin material, the organometallic soap, and the organic solvent in a container, and mixing and dispersing them in a rotating ball mill. The above kneading and dispersion are performed at room temperature. The kneading and dispersion are not limited to kneading and dispersion using a rotating ball mill, and other kneading and dispersion methods may be used.

[0041] After the metal magnetic powder 17, the resin material, the organometallic soap, and the organic solvent are kneaded and dispersed, they are granulated and dried (step S13). This produces granulated powder containing the organometallic soap. In the process of step S13, the mixture produced in step S12 is heat-treated at a temperature equal to or lower than the melting point of the organometallic soap.

[0042] The melting point of zinc stearate contained in the organometallic soap is 116°C to 125°C, the melting point of magnesium stearate is 120°C to 140°C, and the melting point of calcium stearate is 145°C to 160°C. For example, the mixture is heat-treated at a temperature of 115°C or lower. More preferably, the mixture is heat-treated at a temperature of 90°C or higher and 110°C or lower. This heat treatment step is the first heat treatment step.

[0043] This heat treatment removes the organic solvent from the mixture, and a granulated powder (magnetic material) is obtained in which the metal magnetic powder 17, the resin material, and the organometallic soap are integrated together. Note that the granulated powder does not contain any glass material (e.g., silicate glass).

[0044] Next, the granulated powder (magnetic material) granulated in step S13 is further pulverized (step S14) to reduce the particle size. This step is a powderization step. After that, the powdered granulated powder is classified into predetermined particle sizes (step S15). As a result, powdered granulated powder with a powder size of 100 μm to 500 μm is obtained.

[0045] In the granulated powder, an insulating material 18 is formed on the surface of the metal magnetic powder 17. The thickness of the insulating material 18 is, for example, about 10 nm. However, the thickness of the insulating material 18 is not limited to this, and may be 1 nm to 200 nm.

[0046] FIG. 5 is a schematic diagram showing the granulated powder 30 according to the present embodiment, which is powdered after granulation and drying. As shown in FIG. 5, the organic metal soap 31 is present inside the powdered granulated powder 30. Specifically, the resin material 32 is present between the adjacent metal magnetic powders 17, and the organic metal soap 31 is present inside the resin material 32. This softens the resin material contained in the granulated powder 30, and plasticizes the granulated powder 30. Therefore, when the magnetic material, which is the granulated powder 30, is pressure-molded in the core manufacturing process, the flowability of the magnetic material can be increased, and the density (filling rate) of the metal magnetic powder 17 contained in the divided magnetic core (powder magnetic core) 12 can be increased.

[0047] 6 is a flow chart showing a core manufacturing process according to the present embodiment, in which a magnetic core is manufactured by molding a magnetic material.

[0048] First, before the powdered granulated powder 30 is placed in a molding die, a lubricant is mixed with the powdered granulated powder 30.

[0049] Fig. 7 is a schematic diagram of granulated powder 30 according to the present embodiment before pressure molding. As shown in Fig. 7, lubricant 33 is formed on a part of the periphery of granulated powder 30. Lubricant 33 is the same material as the organometallic soap added in step S12. Lubricant 33 is formed, for example, by a spray drying method in which a liquid material is sprayed and dried. As a result, granulated powder (magnetic material) 30 having lubricant 33 on the periphery is formed.

[0050] The lubricant is also applied to the surface of the molding die. For example, the lubricant is applied by spraying an organometallic soap dispersed in a solvent into the molding die. This can improve the lubricity of the granulated powder 30 with respect to the molding die.

[0051] Next, the magnetic material made of the granulated powder 30 is pressure-molded into a predetermined shape (step S21). This step is the first molding step. Specifically, the magnetic material is placed in a molding die and compressed to produce a molded body. At this time, for example, a constant pressure of 10 [ton / cm 2 The shape of the compact is, for example, the shape of the split magnetic core 12 shown in Fig. 1B. Note that the shape of the compact is not limited thereto, and may be, for example, a shape in which the core portion 12b of the split magnetic core 12 is configured as a separate body.

[0052] Thereafter, the compact is degreased by heating it at a temperature of 200 to 450°C in an inert gas atmosphere such as N2 gas or in the air (step S22). This removes the second resin material (binder) contained in the compact. Depending on the type and characteristics of the second resin material used, the degreasing step may be omitted.

[0053] Furthermore, the molded body after debinding is annealed (heat treated) (step S23). The annealing process at this time is the second heat treatment process. For example, an atmosphere-controlled electric furnace is used for annealing the molded body. Examples of the atmosphere-controlled electric furnace include a box furnace, a tubular furnace, and a belt furnace. Note that the method is not limited to these, and other methods may be used.

[0054] The compact is annealed, for example, at a predetermined oxygen partial pressure and an annealing temperature of 800° C. for one hour.

[0055] The annealing temperature and the annealing time are not limited to those mentioned above, and may be, for example, 600 to 1000°C and several tens of minutes to several hours. By performing annealing, the molded body is relieved from the distortion caused by the pressure during uniaxial molding. By annealing, at least a part of the insulating material 18 in the molded body may be decomposed.

[0056] Next, the annealed molded body is impregnated with a resin material (step S24). The resin material may be, for example, an epoxy resin. By impregnating the molded body with the resin material, the strength of the molded body can be improved.

[0057] Through the above steps, a split magnetic core (powder magnetic core) containing metal magnetic powder 17 and insulating material 18 is formed as shown in Fig. 2. Note that two split magnetic cores 12 are formed here as the magnetic core. The coil component 1 can be obtained by assembling the two split magnetic cores 12 and the coil portion as follows.

[0058] FIG. 8 is a flowchart showing the coil assembly process according to the present embodiment.

[0059] First, a coil is formed by winding the conductor 13 a predetermined number of times (step S31).

[0060] Next, the split magnetic cores 12, the conductor 13, and the coil support 14 are assembled (step S32). As shown in FIG. 1B, the conductor 13 is arranged so as to surround the periphery of the cores 12b of the two split magnetic cores 12. At this time, the cylindrical portions 14b of the two coil supports 14 are arranged between the conductor 13 and the respective cores 12b of the two split magnetic cores 12. Also, the annular base portions 14a of the two coil supports 14 are arranged between the conductor 13 and the respective bases 12a of the two split magnetic cores 12. At this time, the ends of the cylindrical portions 14b of the two coil supports 14 opposite to the side on which the annular base portion 14a is formed are arranged so as to abut against each other.

[0061] The two split magnetic cores 12 are arranged so that their core portions 12b and wall portions 12c abut against each other. In this manner, the conductor 13 is incorporated into the split magnetic cores 12 via the coil support 14, thereby assembling the coil component 1. This completes a configuration in which the conductor 13 is wound around the core portions 12b of the split magnetic cores 12. In other words, the split magnetic cores 12 become magnetic cores in which the core portions 12b penetrate the conductor 13 in the direction of the winding axis of the conductor 13.

[0062] Furthermore, the assembled coil component 1 is molded with a resin material (step S33), whereby the coil component 1 is completed.

[0063] [1-3. Filling rate of metal magnetic powder in magnetic core and magnetic properties of magnetic core] Hereinafter, the filling rate of the metal magnetic powder contained in the magnetic core of the coil component 1 and the magnetic characteristics of the magnetic core will be described in order with reference to Examples 1, 2 and 3.

[0064] In Example 1, an example in which the organometallic soap was not added, an example in which the organometallic soap was added internally, and an example in which the organometallic soap was added externally will be described. Note that "internal addition" means that the organometallic soap is added in step S12 (kneading and dispersion), and "external addition" means that a lubricant is applied to the outer periphery of the granulated powder before pressure molding, which is before step 21.

[0065] Fig. 9A is a diagram showing the additives contained in the magnetic material of Example 1 of the present embodiment, the filling rate of the metal magnetic powder contained in the magnetic core, and the initial magnetic permeability of the magnetic core. Fig. 9B is a graph showing the additives contained in the magnetic material of Example 1 of the present embodiment, the density of the metal magnetic powder in the magnetic core, and the initial magnetic permeability of the magnetic core.

[0066] In Example 1, sample A1 was prepared in which no organic metal soap was added to the metal magnetic powder (Fe-Si-Al) and resin material (silicon resin and acrylic resin), sample A2 was prepared in which zinc stearate was added externally to the metal magnetic powder and resin material as a lubricant, and sample A3 was prepared in which zinc stearate was added internally to the metal magnetic powder and resin material as an organic metal soap. Then, the filling rate and density of the metal magnetic powder in the magnetic core were obtained for each of samples A1 to A3. In addition, the initial permeability, which is an example of the magnetic properties of the magnetic core, was examined for each of samples A1 to A3. Note that the density is the density of the magnetic core after the second heat treatment process, and the filling rate is the ratio of the metal magnetic powder per unit volume of the magnetic core after the second heat treatment process.

[0067] 9A and 9B show that sample A2, to which a lubricant was added externally, had a higher packing rate, density, and initial permeability than sample A1, to which no additive was added.Also, sample A3, to which an organometallic soap was added internally, had a higher packing rate, density, and initial permeability than samples A1 and A2.

[0068] In this way, the filling rate, density and initial permeability of the metal magnetic powder in the magnetic core can be increased by adding the organometallic soap during the process of kneading and dispersing the metal magnetic powder, resin material and organic solvent to produce a magnetic material, i.e., by adding the organometallic soap internally. Also, by adding the organometallic soap internally, the filling rate of the metal magnetic powder can be increased without the need for a process of adding the organometallic soap externally.

[0069] As mentioned above, organic metal soaps have long-chain hydrocarbons and are therefore compatible with resin materials. Therefore, by adding organic metal soaps in the granulated powder manufacturing process, the resin material contained in the granulated powder can be softened and the granulated powder can be plasticized. This makes it possible to suppress the entanglement of the molecules of the resin material during pressure molding, and is thought to increase the filling rate of the metal magnetic powder contained in the magnetic core.

[0070] Next, a description will be given of Example 2. In Example 2, an example in which the type of material contained in the organometallic soap 31 is changed will be described.

[0071] FIG. 10 is a diagram showing the additive material contained in the magnetic material of Example 2 of the present embodiment, the filling rate of the metal magnetic powder contained in the magnetic core, and the initial permeability of the magnetic core.

[0072] In Example 2, sample B1 was prepared by adding no organic metal soap to the metal magnetic powder (Fe-Si-Al) and resin material (silicon resin and acrylic resin), sample B2 was prepared by adding zinc stearate to the metal magnetic powder and resin material as an organic metal soap, sample B3 was prepared by adding magnesium stearate to the metal magnetic powder and resin material as an organic metal soap, and sample B4 was prepared by adding calcium stearate to the metal magnetic powder and resin material as an organic metal soap.Then, the filling rate and density of the metal magnetic powder in the magnetic core were obtained for each of samples B1 to B4.In addition, the initial magnetic permeability of the magnetic core was examined for each of samples B1 to B4.

[0073] 10 shows that sample B2 with zinc stearate added internally, sample B3 with magnesium stearate added internally, and sample B4 with calcium stearate added internally have higher packing ratios and initial magnetic permeabilities than sample B1 with no additive added. It also shows that sample B2 with zinc stearate added internally has a higher initial magnetic permeability than samples B3 and B4.

[0074] In this way, adding zinc stearate during the process of kneading and dispersing metal magnetic powder, resin material and organic solvent to produce a magnetic material, i.e., adding zinc stearate internally among various materials of metal stearate, can increase the filling rate, density and initial permeability of the metal magnetic powder in the magnetic core.

[0075] Next, a description will be given of Example 3. In Example 3, an example in which the amount of the organometallic soap 31 added was changed will be described.

[0076] Fig. 11A is a diagram showing the additives contained in the magnetic material of Example 3 of the present embodiment, the filling rate of the metal magnetic powder contained in the magnetic core, and the initial magnetic permeability of the magnetic core. Fig. 11B is a graph showing the additives contained in the magnetic material of Example 3 of the present embodiment, the density of the metal magnetic powder in the magnetic core, and the initial magnetic permeability of the magnetic core.

[0077] In Example 3, sample C1 was prepared by adding no organic metal soap to the metal magnetic powder (Fe-Si-Al) and resin material (silicon resin and acrylic resin), sample C2 was prepared by adding 0.05 parts by weight of organic metal soap to the metal magnetic powder and resin material, sample C3 was prepared by adding 0.1 parts by weight of organic metal soap to the metal magnetic powder and resin material, sample C4 was prepared by adding 0.2 parts by weight of organic metal soap to the metal magnetic powder, sample C5 was prepared by adding 0.5 parts by weight of organic metal soap to the metal magnetic powder, and sample C6 was prepared by adding 1.0 parts by weight of organic metal soap to the metal magnetic powder. Then, the filling rate and density of the metal magnetic powder in the magnetic core were obtained for each sample C1 to C6. In addition, the initial magnetic permeability of the magnetic core was examined for each sample C1 to C6. The weight parts shown here are the weight ratio of the organic metal soap in the magnetic material, and are the weight ratio relative to the weight of the metal magnetic powder taken as 100 parts by weight.

[0078] 11A and 11B show that samples C2, C3, C4, and C5 have higher packing ratios, densities, and initial magnetic permeabilities than samples C1 and C6. In other words, the packing ratios, densities, and initial magnetic permeabilities are higher when the weight ratio of the organometallic soap is in the range of 0.05 parts by weight or more and 0.5 parts by weight or less. When the weight ratio of the organometallic soap is in the range of 0.05 parts by weight or more and 0.5 parts by weight or less with respect to the metal magnetic powder, this corresponds to the weight ratio of the organometallic soap being in the range of 5% by weight or more and 40% by weight or less with respect to the resin material.

[0079] In this way, the filling rate, density and initial magnetic permeability of the metal magnetic powder in the magnetic core can be increased by adding 0.05 parts by weight or more and 0.5 parts by weight or less of organometallic soap during the process of kneading and dispersing the metal magnetic powder, resin material and organic solvent to produce a magnetic material, i.e., by internally adding 0.05 parts by weight or more and 0.5 parts by weight or less of organometallic soap.More preferably, the filling rate, density and initial magnetic permeability of the metal magnetic powder in the magnetic core can be increased by internally adding 0.05 parts by weight or more and 0.2 parts by weight or less of organometallic soap.

[0080] [1-4. Effects, etc.] As described above, the manufacturing method of the magnetic material in this embodiment includes a mixture production step of producing a mixture containing an organic solvent, metal magnetic powder, resin material, and organometallic soap, and a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, resin material, and organometallic soap are integrated.

[0081] In this way, by generating a mixture including an organic solvent, metal magnetic powder, resin material, and organometallic soap in the mixture generation process, the magnetic material generated after the first heat treatment process can be plasticized. This makes it possible to increase the filling rate of the metal magnetic powder in the magnetic core generated by the magnetic material and increase the magnetic permeability of the magnetic core. In other words, it is possible to provide a magnetic material that can obtain high magnetic properties.

[0082] The organometallic soap may also include zinc stearate.

[0083] In this way, by including zinc stearate in the organometallic soap, it is possible to increase the filling rate of the metal magnetic powder included in the magnetic core and improve the magnetic permeability of the magnetic core, thereby providing a magnetic material that can achieve high magnetic properties.

[0084] The weight ratio of the organometallic soap in the magnetic material may be 0.05% by weight or more and 0.5% by weight or less with respect to the metal magnetic powder.

[0085] By setting the weight ratio of the organometallic soap to the metal magnetic powder as shown above, the filling rate of the metal magnetic powder contained in the magnetic core can be increased, and the magnetic permeability of the magnetic core can be improved. In other words, a magnetic material for obtaining high magnetic properties can be provided.

[0086] The weight ratio of the organometallic soap in the magnetic material may be 5% by weight or more and 40% by weight or less with respect to the resin material.

[0087] By setting the weight ratio of the organometallic soap to the resin material as shown above, the filling rate of the metal magnetic powder contained in the magnetic core can be increased, and the magnetic permeability of the magnetic core can be improved. In other words, a magnetic material for obtaining high magnetic properties can be provided.

[0088] The resin material may also include a thermoplastic material.

[0089] This allows the resin material to be softened compared to when the resin material is a thermosetting resin. This allows the filling rate of the metal magnetic powder contained in the magnetic core to be increased, improving the magnetic permeability of the magnetic core. In other words, it is possible to provide a magnetic material that can achieve high magnetic properties.

[0090] In the mixture producing step, the mixture may be produced by kneading an organic solvent, a metal magnetic powder, a resin material, and an organometallic soap at room temperature.

[0091] This allows the resin material to be softened compared to when the resin material is kneaded at a high temperature. This allows the filling rate of the metal magnetic powder contained in the magnetic core to be increased, improving the magnetic permeability of the magnetic core. In other words, it is possible to provide a magnetic material that can achieve high magnetic properties.

[0092] In the first heat treatment step, the mixture may be heated to a temperature equal to or lower than the melting point of the organometallic soap.

[0093] This makes it possible to suppress the resin material from being hardened by heating and to soften the resin material, thereby increasing the filling rate of the metal magnetic powder contained in the magnetic core and improving the magnetic permeability of the magnetic core. In other words, it is possible to provide a magnetic material that can achieve high magnetic properties.

[0094] The method for manufacturing a powder magnetic core according to this embodiment includes a first molding step in which the magnetic material obtained by the above-mentioned method for manufacturing a magnetic material is pressed under high pressure to obtain a molded body, and a second heat treatment step in which the molded body obtained in the first molding step is heated.

[0095] By compressing the powder of the magnetic material in this manner, a dust core can be easily formed.

[0096] The dust core according to the present embodiment contains metal magnetic powder composed of Fe-Si-Al, and the metal magnetic powder has a packing rate of 82% or more and an initial magnetic permeability of 125 or more.

[0097] According to this configuration, in a dust core using metal magnetic powder made of Fe-Si-Al, it is possible to improve the packing rate of the metal magnetic powder and improve the magnetic permeability of the dust core.

[0098] The coil component according to the present embodiment includes the above-described powder magnetic core and a coil.

[0099] According to this configuration, it is possible to provide a coil component including a powder magnetic core having the above-mentioned characteristics.

[0100] The granulated powder according to the present embodiment is a granulated powder containing a metal magnetic powder, a resin material, and an organometallic soap, and at least a portion of the organometallic soap is present inside the granulated powder.

[0101] In this way, the presence of the organometallic soap inside the granulated powder can soften the resin material and plasticize the granulated powder, thereby increasing the packing rate of the metal magnetic powder during compaction and improving the magnetic properties of the powder core.

[0102] Also, at least a portion of the resin material may be present between adjacent metal magnetic powder particles, and the organometallic soap may be present in the resin material present between adjacent metal magnetic powder particles.

[0103] In this way, the presence of the organometallic soap in the resin material between adjacent metal magnetic powder particles softens the resin material and plasticizes the granulated powder, thereby increasing the packing rate of the metal magnetic powder during compaction and improving the magnetic properties of the powder core.

[0104] (Embodiment 2) Next, a description will be given of embodiment 2. Coil component 1 according to embodiment 1 is a coil component that uses a so-called dust core as a magnetic core, but coil component 2 according to the present embodiment is a metal composite type coil component in which a coil is incorporated into a magnetic core during the manufacturing process.

[0105] [2-1. Composition of magnetic materials] Fig. 12A is a schematic perspective view showing the configuration of coil device 2 according to the present embodiment. Fig. 12B is a cross-sectional view showing the configuration of coil device 2 according to the present embodiment. Fig. 12B shows a cross section taken along line XIIB-XIIB in Fig. 12A.

[0106] As shown in FIGS. 12A and 12B, the coil device 2 includes a magnetic core portion 22 made of a metal composite material, and a coil portion .

[0107] The magnetic core portion 22 has a cylindrical core portion 22a near the center when viewed from above. The magnetic material constituting the magnetic core portion 22 is, for example, an Fe-Si-based metallic magnetic material that is an alloy mainly composed of Fe and Si, similar to the split magnetic core 12 of the coil component 1 according to the first embodiment. The magnetic material is similar to the magnetic material shown in the first embodiment, but the resin of the magnetic material in the second embodiment may be composed of only a thermosetting resin. The coil portion 23 is disposed around the cylindrical core portion 22a of the magnetic core portion 22.

[0108] The coil portion 23 has a winding portion 23a in which a conductor is wound multiple times, and a wiring portion 23b formed on the outside of the magnetic core portion 22. A core portion 22a of the magnetic core portion 22 is disposed as a winding axis of the wound conductor of the winding portion 23a. The conductor is made of, for example, copper. The conductor is made of a material that is not destroyed by heat applied when the coil component 2 is formed.

[0109] The coil portion 23 is formed integrally with the magnetic core portion 22. A wound portion 23a of the coil portion 23 is embedded in the magnetic core, and a wiring portion 23b is disposed on the outside of the magnetic core portion 22.

[0110] [2-2. Manufacturing method of coil parts] A method for manufacturing the coil component 2 according to this embodiment will be described below. Fig. 13 is a flowchart showing the manufacturing process of the coil component 2 according to this embodiment.

[0111] As shown in Fig. 13, the manufacturing process of the coil component 2 includes a granulated powder manufacturing process (step S10) and a core manufacturing and coil assembly process (step S40). In the granulated powder manufacturing process, a magnetic material that constitutes the above-mentioned magnetic core is produced. In the core manufacturing process, the magnetic core portion 22 and the coil portion 23 are formed by molding the magnetic material, and the coil component 2 is completed by assembling the magnetic core portion 22 and the coil portion 23.

[0112] The granulated powder manufacturing process in the manufacturing process of the coil component 2 is similar to the granulated powder manufacturing process described in the first embodiment, and therefore the description thereof will be omitted.

[0113] The core manufacturing and coil assembly steps will be described in detail below. Fig. 14 is a flow chart showing the core manufacturing and coil assembly steps according to this embodiment.

[0114] 14, first, the coil portion 23 is formed (step S41). Similar to the conductor 13 shown in the first embodiment, the coil portion 23 is formed by winding a conductor made of a metal such as copper a predetermined number of times to form the wound portion 23a.

[0115] Next, the magnetic core portion 22 and the coil portion 23 are molded integrally (step S42). Step S42 is a second molding step. The magnetic core portion 22 is made of a magnetic material produced in a granulated powder production process. First, the magnetic material classified in the granulated powder production process is placed in a molding die. At this time, the coil portion 23 and the magnetic material are placed in the molding die so that the magnetic material covers the entire portion of the coil portion 23 except for the end of the conductor winding portion 23a.

[0116] Next, for example, a constant pressure of 4 to 5 ton / cm 2 ] to produce a compact. The pressure used here is lower than the pressure used in the uniaxial molding in the core manufacturing process of the coil component 1 shown in the first embodiment. This makes it possible to prevent the coil portion 23, which is molded together with the magnetic material, from being destroyed during molding.

[0117] The shape of the molded body is, for example, the shape of the magnetic core portion 22 shown in Figures 12A and 12B. Note that the shape of the molded body is not limited to this, and may be other shapes.

[0118] Furthermore, the molded body is thermally cured (step S43). This step is a third heat treatment step. For example, an atmosphere-controlled electric furnace is used for thermally curing the molded body. However, other methods may be used for thermally curing the molded body.

[0119] The thermal curing of the molded body is carried out, for example, at a temperature of 200°C for one hour under a predetermined oxygen partial pressure. The temperature at this time is lower than the annealing temperature of the molded body of the coil component 1 shown in the first embodiment. This makes it possible to prevent the coil portion 23 from being destroyed during the thermal curing of the molded body.

[0120] Furthermore, after the compact is thermally cured, the end of the wound portion 23a of the coil portion 23 may be connected to the wiring portion 23b disposed on the outside of the magnetic core portion 22.

[0121] Through the above steps, the coil component 2 in which the magnetic core portion 22 and the coil portion 23 are integrated is completed.

[0122] [2-3. Effects, etc.] As described above, the manufacturing method of the coil component in this embodiment includes a second molding step in which the magnetic material obtained by the above-mentioned magnetic material manufacturing method and a coil are integrated by powder molding to obtain a molded body, and a third heat treatment step in which the molded body obtained in the second molding step is heated.

[0123] According to this configuration, a coil component in which the powder magnetic core and the coil are integrated can be easily formed.

[0124] (Other embodiments, etc.) Although the manufacturing method of the magnetic material according to the embodiment of the present disclosure has been described above, the present disclosure is not limited to this embodiment.

[0125] For example, the present invention also includes coil components using the above-mentioned magnetic materials. Examples of coil components include inductance components such as high-frequency reactors, inductors, and transformers. In addition, the present invention also includes power supply devices equipped with the above-mentioned coil components.

[0126] Furthermore, the metal magnetic powder is not limited to Fe-Si and Fe-Si-Al magnetic materials, but may be other magnetic materials containing Fe as a main component.

[0127] The first resin material for forming the insulating material 18 may be a metal chelate complex containing a metal such as Al, Ti, or Zr as a main component, an oligomer, an acylate coupling agent, a polymer (resin), or the like. The oligomer may be, for example, a cyclic aluminum oligomer. The main component of the first resin material may be an aluminum organic compound. The molecular weight of the first resin material may be, for example, 300 or more and 1000 or less. Note that the molecular weight of the first resin material is not limited to this, and may be less than 300 or more than 1000.

[0128] The main component of the first resin material may be a chelate complex other than an Al chelate complex, or a chelate complex containing another metal. In addition to the chelate complex, the first resin material may contain an oligomer, an acylate, a polymer, or the like as a main component.

[0129] The resin material may be the above-mentioned acrylic resin, silicone resin, butyral resin, or other resin material. The organic solvent is not limited to the above-mentioned toluene, xylene, ethanol, etc., and other organic solvents may be used.

[0130] In addition, the method of kneading and dispersing the Fe-Si-based metal magnetic material, and the method of mixing the metal magnetic powder, resin material, organometallic soap, organic solvent, etc. are not limited to the kneading and dispersion using a rotating ball mill described above, and other mixing methods may be used.

[0131] The heat treatment methods in the first heat treatment step, the second heat treatment step, and the third heat treatment step are not limited to the above-mentioned methods, and other methods may be used. The pressure, temperature, and time in each step described above are merely examples, and other pressures, temperatures, and times may be used.

[0132] Furthermore, the present disclosure is not limited to the embodiment. As long as it does not deviate from the gist of the present disclosure, various modifications conceived by a person skilled in the art to the present embodiment and forms constructed by combining components in different embodiments may also be included within the scope of one or more aspects. [Industrial Applicability]

[0133] The magnetic material according to the present disclosure can be used as a material for high-frequency inductors, magnetic cores of transformers, and the like. [Explanation of symbols]

[0134] 1, 2 Coil parts 12 Split magnetic core (powder magnetic core) 12a base 12b Core 12c wall 13 Conductor (coil) 14 Coil support 14a base 14b Cylindrical part 17 Metal magnetic powder 18 Insulation materials 22 Magnetic core (magnetic material) 22a Core 23 Coil section (coil) 23a Winding section 23b Wiring section 30 Granulated powder (magnetic material) 31 Organometallic soaps 32 Resin materials 33 Lubricants

Claims

1. A method for producing a powder magnetic core, comprising the steps of: a mixture producing step of producing a mixture containing an organic solvent, a metal magnetic powder, a resin material containing an acrylic resin, and an organometallic soap; a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, the resin material, and the organometallic soap are integrated; a first molding step of high-pressure pressing the magnetic material obtained in the first heat treatment step to obtain a molded body; A second heat treatment step of heating the molded body obtained in the first molding step; Including, The temperature of the second heat treatment step is 600° C. to 1000° C. The filling rate of the metal magnetic powder in the powder magnetic core is 82% or more and 83% or less. A method for manufacturing a powder magnetic core.

2. The organometallic soap comprises zinc stearate. A method for producing the powder magnetic core according to claim 1 .

3. The weight ratio of the organometallic soap contained in the magnetic material is 0.05% by weight or more and 0.5% by weight or less with respect to the metal magnetic powder. A method for producing the powder magnetic core according to claim 2.

4. The weight ratio of the organometallic soap contained in the magnetic material is 5% by weight or more and 40% by weight or less with respect to the resin material. The method for producing the powder magnetic core according to any one of claims 1 to 3.

5. the resin material includes a thermoplastic material; The first molding step is a step of applying a lubricant containing the same material as the organometallic soap to the magnetic material obtained in the first heat treatment step, and then pressing the magnetic material under high pressure to obtain a molded body. The method for producing the powder magnetic core according to any one of claims 1 to 4.

6. In the mixture producing step, the mixture is produced by kneading the organic solvent, the metal magnetic powder, the resin material and the organometallic soap at room temperature. The method for producing the powder magnetic core according to any one of claims 1 to 5.

7. In the first heat treatment step, the mixture is heated to a temperature not higher than the melting point of the organometallic soap, and the mixture is heat-treated at a temperature not lower than 90° C. and not higher than 110° C. The method for producing the powder magnetic core according to any one of claims 1 to 6.

8. a mixture producing step of producing a mixture containing an organic solvent, a metal magnetic powder, a resin material containing an acrylic resin, and an organometallic soap; a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, the resin material, and the organometallic soap are integrated; a first molding step of high-pressure pressing the magnetic material obtained in the first heat treatment step to obtain a molded body; A second heat treatment step of heating the molded body obtained in the first molding step; Including, The temperature of the second heat treatment step is 800° C. to 1000° C. A method for manufacturing a powder magnetic core.

9. a mixture producing step of producing a mixture containing an organic solvent, a metal magnetic powder, a resin material containing an acrylic resin, and an organometallic soap; a first heat treatment step of heating the mixture and removing the organic solvent in the mixture to obtain a magnetic material in which the metal magnetic powder, the resin material, and the organometallic soap are integrated; a first molding step of high-pressure pressing the magnetic material obtained in the first heat treatment step to obtain a molded body; A second heat treatment step of heating the molded body obtained in the first molding step; Including, The molding pressure in the first molding step is 10 ton / cm ２ ], The temperature of the second heat treatment step is 600° C. to 1000° C. A method for manufacturing a powder magnetic core.

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