Inductor and method for manufacturing inductor

Abstract

Provided are: an inductor having a high degree of freedom in design in terms of an inductance value (L value) and a DC superimposed current Isat that correspond to each user request; and a method for manufacturing said inductor. An inductor 1 according to the present disclosure is provided with a magnetic body 10, and a conductor 20 provided in the magnetic body 10. The magnetic body 10 includes a first core 11 including first magnetic particles 11p, and a second core 12 including second magnetic particles 12p of which the circularity is larger than that of the first magnetic particles 11p. The first core 11 and the second core 12 are in contact with each other. At least a portion of the conductor 20 is embedded in the second core 12.

Description

Inductor and method for manufacturing the same

[0001] The present disclosure relates to inductors and methods for manufacturing inductors.

[0002] Conventionally known inductors made of ferrite materials have the problem of a large drop in inductance (L value) when a large current is superimposed. Therefore, development of inductors using metal composite materials containing metal powder and resin instead of ferrite materials is currently underway.

[0003] Patent Document 1 discloses an inductor using a metal composite material, which includes a magnetic substrate containing soft magnetic metal particles containing iron, a first external electrode and a second external electrode attached to the magnetic substrate, and an internal conductor provided within the magnetic substrate, one end of which is electrically connected to the first external electrode and the other end of which is electrically connected to the second external electrode, and which extends linearly from the first external electrode to the second external electrode in a plan view.

[0004] Japanese Patent Application Laid-Open No. 2020-167273

[0005] The characteristics required for an inductor (inductance value and / or DC superposition linearity) vary from user to user, and different characteristics are required for each user.

[0006] The inductor described in Patent Document 1 simply has an internal conductor disposed within a magnetic substrate, and the inductance value and the DC superimposed current I ｓａｔ It has been difficult to meet the requirements of individual users. More specifically, the inductor described in Patent Document 1 has an inductance value and a DC superimposed current I ｓａｔ In this specification, the DC superimposed current I ｓａｔ " refers to the current value at which the inductance value is reduced by 30% from the initial value (the inductance when the DC value is zero) when the DC value of the current applied to the coil is changed and measured with an LCR meter. Also, using parameters such as the dimensions of the magnetic substrate and the number of turns of the internal conductor, "DC superimposed current I ｓａｔ "When "magnetic field H ｓａｔ」It is also possible to calculate

[0007] The present disclosure has been made in view of the above problem. That is, the main object of the present disclosure is to provide a method for determining the inductance value (L value) and the DC superimposed current I ｓａｔ The present invention provides an inductor with a high degree of freedom in design and a method for manufacturing the inductor.

[0008] The inductor of the present disclosure comprises a magnetic body and a conductor disposed within the magnetic body, wherein the magnetic body includes a first core including first magnetic particles and a second core including second magnetic particles having a greater circularity than the first magnetic particles, the first core and the second core being in contact with each other, and the conductor being at least partially embedded in the second core.

[0009] The method for manufacturing an inductor disclosed herein includes the steps of: compacting a first magnetic material containing first magnetic particles and a first resin to form a first core; arranging a conductor on the first core; arranging a second magnetic material containing second magnetic particles and a second resin on the conductor; and compression-molding the first core, the conductor, and the second magnetic material at a pressure lower than the pressure used during the compacting process.

[0010] According to the inductor and the method for manufacturing the inductor disclosed herein, the inductance value (L value) and the DC superimposed current I ｓａｔ This allows for a high degree of freedom in design, making it possible to provide an inductor that can easily meet the needs of individual users.

[0011] FIG. 1A is a perspective view of an inductor according to the first embodiment. FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. FIG. 1C is a cross-sectional view taken along line IC-IC in FIG. 1A. FIG. 1D is an enlarged cross-sectional view of the dashed line area in FIG. 1B. FIG. 2A is a perspective view of an inductor according to a first modification of the first embodiment. FIG. 2B is a cross-sectional view taken along line IIB-IIB in FIG. 2A. FIG. 2C is a cross-sectional view taken along line IIC-IIC in FIG. 2A. FIG. 3A is a perspective view of an inductor according to a second modification of the first embodiment. FIG. 3B is a cross-sectional view taken along line IIIB-IIIB in FIG. 3A. FIG. 3C is a cross-sectional view taken along line IIIC-IIIC in FIG. 3A. FIG. 4A is a perspective view of an inductor according to a third modification of the first embodiment. FIG. 4B is a cross-sectional view taken along line IVB-IVB in FIG. 4A. FIG. 4C is a cross-sectional view taken along line IVC-IVC in FIG. 4A. FIG. 5A is a perspective view of an inductor according to Modification 4 of the first embodiment. FIG. 5B is a cross-sectional view taken along line VB-VB in FIG. 5A. FIG. 5C is a cross-sectional view taken along line VC-VC in FIG. 5A. FIG. 6A is a perspective view of an inductor according to Modification 5 of the first embodiment. FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A. FIG. 6C is a cross-sectional view taken along line VIC-VIC in FIG. 6A. FIG. 7A is a perspective view of an inductor according to Modification 6 of the first embodiment. FIG. 7B is a cross-sectional view taken along line VIIIB-VIIIB in FIG. 7A. FIG. 7C is a cross-sectional view taken along line VIIIC-VIIC in FIG. 7A. FIG. 8A is a perspective view of an inductor according to Modification 7 of the first embodiment. FIG. 8B is a cross-sectional view taken along line VIIIB-VIIIB in FIG. 8A. FIG. 8C is a cross-sectional view taken along line VIIIC-VIIIC in FIG. 8A. FIG. 9A is a perspective view of an inductor according to the second embodiment. FIG. 9B is a cross-sectional view taken along line IXB-IXB in FIG. 9A. FIG. 9C is a cross-sectional view taken along line IXC-IXC in FIG. 9A. FIG. 10A is a perspective view of an inductor according to a first modified example of the second embodiment. FIG. 10B is a cross-sectional view taken along line XB-XB in FIG. 10A. FIG. 10C is a cross-sectional view taken along line XC-XC in FIG. 10A. FIG. 11A is a perspective view of an inductor according to a second modified example of the second embodiment. FIG. 11B is a cross-sectional view taken along line XIB-XIB in FIG. 11A.FIG. 11C is a cross-sectional view taken along the arrow direction of line XIC-XIC in FIG. 11A. FIG. 12A is a perspective view of an inductor according to Modification 3 of the second embodiment. FIG. 12B is a cross-sectional view taken along the arrow direction of line XIIB-XIIB in FIG. 12A. FIG. 12C is a cross-sectional view taken along the arrow direction of line XIIC-XIIC in FIG. 12A. FIG. 13A is a perspective view of an inductor according to Modification 4 of the second embodiment. FIG. 13B is a cross-sectional view taken along the arrow direction of line XIIIB-XIIIB in FIG. 13A. FIG. 13C is a cross-sectional view taken along the arrow direction of line XIIIC-XIIIC in FIG. 13A. FIG. 14A is a perspective view of an inductor according to Modification 5 of the second embodiment. FIG. 14B is a cross-sectional view taken along the arrow direction of line XIVB-XIVB in FIG. 14A. FIG. 14C is a cross-sectional view taken along the arrow direction of line XIVC-XIVC in FIG. 14A. FIG. 15A is a perspective view of an inductor according to Modification 6 of the second embodiment. FIG. 15B is a cross-sectional view taken along the arrows XVB-XVB in FIG. 15A. FIG. 15C is a cross-sectional view taken along the arrows XVC-XVC in FIG. 15A. FIG. 16A is a perspective view of an inductor according to Modification 7 of the second embodiment. FIG. 16B is a cross-sectional view taken along the arrows XVIB-XVIB in FIG. 16A. FIG. 16C is a cross-sectional view taken along the arrows XVIC-XVIC in FIG. 16A. FIG. 16D is a cross-sectional view taken along the arrows XVID-XVID in FIG. 16A. FIG. 17A is a perspective view of an inductor according to Modification 8 of the second embodiment. FIG. 17B is a cross-sectional view taken along the arrows XVIIB-XVIIB in FIG. 17A. FIG. 17C is a cross-sectional view taken along the arrows XVIIC-XVIIC in FIG. 17A. FIG. 17D is a cross-sectional view taken along the arrows XVIID-XVIID in FIG. 17A. FIG. 18A is a perspective view of an inductor according to a ninth modification of the second embodiment. FIG. 18B is a cross-sectional view taken along line XVIIIB-XVIIIB in FIG. 18A. FIG. 18C is a cross-sectional view taken along line XVIIIC-XVIIIC in FIG. 18A. FIG. 18D is a cross-sectional view taken along line XVIIID-XVIIID in FIG. 18A. FIG. 19A is a perspective view of an inductor according to a tenth modification of the second embodiment. FIG. 19B is a cross-sectional view taken along line XIXB-XIXB in FIG. 19A. FIG. 19C is a cross-sectional view taken along line XIXC-XIXC in FIG. 19A. FIG. 19D is a cross-sectional view taken along line XIXD-XIXD in FIG. 19A.FIG. 20A is a perspective view of an inductor according to the third embodiment. FIG. 20B is a cross-sectional view taken along line XXB-XXB in FIG. 20A . FIG. 20C is a cross-sectional view taken along line XXC-XXC in FIG. 20A . FIG. 21A is a perspective view of an inductor according to a first modified example of the third embodiment. FIG. 21B is a cross-sectional view taken along line XXIB-XXIB in FIG. 21A . FIG. 21C is a cross-sectional view taken along line XXIC-XXIC in FIG. 21A . FIG. 22A is a perspective view of an inductor according to a second modified example of the third embodiment. FIG. 22B is a cross-sectional view taken along line XXIIB-XXIIB in FIG. 22A . FIG. 22C is a cross-sectional view taken along line XXIIC-XXIIC in FIG. 22A . FIG. 23A is a perspective view of an inductor according to a fourth embodiment. FIG. 23B is a cross-sectional view taken along line XXIIIB-XXIIIB in FIG. 23A . 23C is a cross-sectional view taken along the arrows XXIIIC-XXIIIC in FIG. 23A. FIG. 24A is a perspective view of an inductor according to Modification 1 of the fourth embodiment. FIG. 24B is a cross-sectional view taken along the arrows XXIVB-XXIVB in FIG. 24A. FIG. 24C is a cross-sectional view taken along the arrows XXIVC-XXIVC in FIG. 24A. FIG. 25A is a perspective view of an inductor according to Modification 2 of the fourth embodiment. FIG. 25B is a cross-sectional view taken along the arrows XXV-XXVB in FIG. 25A. FIG. 25C is a cross-sectional view taken along the arrows XXVC-XXVC in FIG. 25A. FIG. 26A is a perspective view of an inductor according to Modification 3 of the fourth embodiment. FIG. 26B is a cross-sectional view taken along the arrows XXVIB-XXVIB in FIG. 26A. FIG. 26C is a cross-sectional view taken along the arrows XXVIC-XXVIC in FIG. 26A. Fig. 26D is a cross-sectional view taken along the arrows XXVID-XXVID in Fig. 26A. Fig. 26E is a cross-sectional view taken along the arrows XXVIE-XXVIE in Fig. 26A. Fig. 27A is a perspective view of an inductor according to Modification 4 of the fourth embodiment. Fig. 27B is a cross-sectional view taken along the arrows XXVIIB-XXVIIB in Fig. 27A. Fig. 27C is a cross-sectional view taken along the arrows XXVIIC-XXVIIC in Fig. 27A. Fig. 28A is a perspective view of an inductor according to the fifth embodiment. Fig. 28B is a cross-sectional view taken along the arrows XXVIIIB-XXVIIIB in Fig. 28A. Fig. 28C is a cross-sectional view taken along the arrows XXVIIIC-XXVIIIC in Fig. 28A.FIG. 28D is a cross-sectional view taken along the arrow direction of line XXVIIID-XXVIIID in FIG. 28A. FIG. 29A is a perspective view of an inductor according to Modification 1 of the fifth embodiment. FIG. 29B is a cross-sectional view taken along the arrow direction of line XXIXB-XXIXB in FIG. 29A. FIG. 29C is a cross-sectional view taken along the arrow direction of line XXIXC-XXIXC in FIG. 29A. FIG. 29D is a cross-sectional view taken along the arrow direction of line XXIXD-XXIXD in FIG. 29A. FIG. 30A is a perspective view of an inductor according to Modification 2 of the fifth embodiment. FIG. 30B is a cross-sectional view taken along the arrow direction of line XXXB-XXXB in FIG. 30A. FIG. 30C is a cross-sectional view taken along the arrow direction of line XXXC-XXXC in FIG. 30A. FIG. 31A is a perspective view of an inductor according to Modification 3 of the fifth embodiment. FIG. 31B is a cross-sectional view taken along the arrow direction of line XXXIB-XXXIB in FIG. 31A. Fig. 31C is a cross-sectional view taken along line XXXIC-XXXIC in Fig. 31A. Fig. 31D is a cross-sectional view taken along line XXXID-XXXID in Fig. 31A. Fig. 32 is a flow chart showing a manufacturing process for the inductor of the present disclosure. Fig. 33 is a table showing the results of a demonstration test of the inductor of the present disclosure.

[0012] The inductor of the present disclosure will be described below. Note that the present disclosure is not limited to the following configurations and may be modified as appropriate within the scope of the gist of the present disclosure. Furthermore, the present disclosure also includes combinations of multiple individual preferred configurations described below. The drawings shown below are schematic diagrams, and the dimensions, aspect ratios, and other factors may differ from those of the actual product.

[0013] [Inductor of First Embodiment] The inductor 1 of this embodiment includes a magnetic body 10 and a conductor 20 .

[0014] -Magnetic body- The magnetic body 10 has, for example, a rectangular parallelepiped shape or a substantially rectangular parallelepiped shape having six sides. The magnetic body 10 may have rounded corners and ridges. A corner is a portion where three sides of the magnetic body 10 intersect, and a ridge is a portion where two sides of the magnetic body 10 intersect.

[0015] 1, the length direction, width direction, and height direction of the inductor 1 of this embodiment are indicated as L direction, W direction, and H direction, respectively. The length direction L, width direction W, and height direction H are perpendicular to each other. The mounting surface of the inductor 1 is, for example, a surface (LW surface) parallel to the length direction L and width direction W.

[0016] 1 has a first main surface 10a and a second main surface 10b that face each other in a height direction H, a first end surface 10c and a second end surface 10d that are orthogonal to the height direction H and face each other in a length direction L, and a first side surface 10e and a second side surface 10f that face each other in a width direction W that is orthogonal to the length direction L and the height direction H. In the example shown in FIG. 1, the first main surface 10a of the magnetic body 10 corresponds to the mounting surface (bottom surface) of the magnetic body 10.

[0017] The magnetic body 10 includes a first core 11 including first magnetic particles 11p and a second core 12 including second magnetic particles 12p having a greater circularity than the first magnetic particles 11p, and the first core 11 and the second core 12 are in contact with each other. The first core 11 and the second core 12 will be described in detail below.

[0018] First Core The first core 11 includes first magnetic particles 11p and a first resin 11r (see FIG. 1D).

[0019] The first magnetic particles 11p may be Fe-based metal magnetic particles, such as an Fe alloy. Examples of the Fe alloy include particles of one or more metal magnetic materials selected from the group consisting of an alloy containing Fe and Ni, an alloy containing Fe and Co, an alloy containing Fe and Si, an alloy containing Fe, Si, and Cr, an alloy containing Fe, Si, and Al, an alloy containing Fe, Si, B, and Cr, and an alloy containing Fe, P, Cr, Si, B, Nb, and C.

[0020] The first magnetic particles 11p may be coated with an insulating coating (not shown). By coating the first magnetic particles 11p with the insulating coating, the first magnetic particles 11p may be insulated from each other. In this specification, "insulating" refers to a volume resistivity of 1 MΩcm or more. The insulating coating may be, for example, an inorganic insulating coating formed by a sol-gel reaction of a metal alkoxide and / or an inorganic glass coating formed by a mechanochemical method.

[0021] The first magnetic particles 11p have a smaller circularity than the second magnetic particles 12p described below. For example, the circularity may be less than 0.9. In this specification, the "circularity" is defined as follows: ２ (S is the area of ​​the particle, and L is the circumferential length of the particle) and is an index showing the complexity of the particle shape. Note that the closer the circularity is to 1, the closer the particle shape is to a perfect circle.

[0022] The circularity of the first magnetic particles is measured and calculated as follows. First, the inductor 1 is polished, and the cross section of the first core 11 is exposed using FIB (Focused Ion Beam), cross-section ion milling (CP), or the like to form an exposed surface. Then, each first magnetic particle 11p is observed at 500x to 5000x magnification using an SEM (Scanning Electron Microscope). Using image analysis software WinROOF 2018 (Mitani Corporation), the area S and perimeter L of 10 or more first magnetic particles 11p are measured, and the average value is used as the circularity in this specification. Furthermore, while the first magnetic particles 11p are shown as flattened in FIG. 1D for convenience of illustration, a low circularity does not necessarily mean that they are flattened, but also includes irregularly crushed and deformed particles.

[0023] As an example of achieving the desired circularity for the first magnetic particles 11p, the first core 11 may be formed by powder compacting a first magnetic material containing the first magnetic particles 11p, as will be described in detail in the "Inductor Manufacturing Method" section below.

[0024] The first resin 11r is not particularly limited, but may be, for example, a thermosetting resin, such as at least one selected from the group consisting of epoxy resin, silicone resin, polyester resin, polyimide resin, polyolefin resin, and phenol resin. In particular, when an epoxy resin is used as the first resin 11r, a magnetic body 10 having high electrical insulation properties and / or mechanical strength can be obtained.

[0025] Second Core The second core 12 includes second magnetic particles 12p and a second resin 12r (see FIG. 1D).

[0026] The second magnetic particles 12p may be made of the same material as the first magnetic particles 11p, or may be made of a different material. For example, the second magnetic particles 12p may be made of one or more metallic magnetic materials selected from the group consisting of an alloy containing Fe and Ni, an alloy containing Fe and Co, an alloy containing Fe and Si, an alloy containing Fe, Si and Cr, an alloy containing Fe, Si and Al, an alloy containing Fe, Si, B and Cr, and an alloy containing Fe, P, Cr, Si, B, Nb and C.

[0027] The second magnetic particles 12p may be coated with an insulating coating (not shown). By coating the second magnetic particles 12p with the insulating coating, the second magnetic particles 12p may be insulated from each other. The insulating coating may be, for example, an inorganic insulating coating formed by a sol-gel reaction of a metal alkoxide and / or an inorganic glass coating formed by a mechanochemical method.

[0028] The second magnetic particles 12p may have a circularity greater than that of the first magnetic particles 11p. For example, the circularity may be 0.9 or greater.

[0029] As an example of achieving the desired circularity for the second magnetic particles 12p, as will be described in detail in the "Inductor manufacturing method" section below, the second core 12 may be formed by compression molding a second magnetic material containing the second magnetic particles 12p at a pressure lower than the pressure used during powder molding to form the first core 11.

[0030] The second resin 12r is not particularly limited, but may be, for example, a thermosetting resin, such as at least one selected from the group consisting of epoxy resin, silicone resin, polyester resin, polyimide resin, polyolefin resin, and phenolic resin. In particular, when an epoxy resin is used as the second resin 12r, the magnetic body 10 can have high electrical insulation and / or mechanical strength. The second resin 12r may be the same material as the first resin 11r, or a different material.

[0031] 1A to 1C, the conductor 20 of the inductor 1 of this embodiment is provided in the magnetic body 10. Specifically, the conductor 20 includes a linear portion 21 extending from the first end face 10c toward the second end face 10d of the magnetic body 10, and electrode portions 22 provided on both ends of the linear portion 21 and extending toward the first main surface 10a (see FIG. 1B in particular).

[0032] The material of the conductor 20 may contain copper. Alternatively, a copper-clad aluminum conductor wire or an aluminum conductor wire may be used. The conductor 20 may be a rectangular wire having a rectangular cross section, or a round wire having a round cross section. Figures 1A to 1C show an embodiment in which a rectangular wire is used as the conductor 20.

[0033] The conductor 20 may be at least partially embedded in the second core 12. In this specification, "embedded" refers not only to the case where the entire outer surface of the conductor 20 is covered by the second core 12, but also to the case where a portion of the outer surface of the conductor 20 is in contact with the second core 12. In Fig. 1B showing an example, the lower and side surfaces of the wire portion 21 of the conductor 20 are in contact with the second core 12, but the upper surface is not in contact with the second core 12.

[0034] A suitable embodiment of the conductor 20 may have an insulating coating on the surface of the conductor 20. As described above, the second core 12 is insulating, and therefore insulation can be ensured even without providing an insulating coating on the surface of the conductor 20. However, by providing an insulating coating on the conductor 20, insulation from the second core 12 can be further improved.

[0035] As described above, in the inductor 1 of this embodiment, the circularity of the first magnetic particles 11p contained in the first core 11 and the circularity of the second magnetic particles 12p contained in the second core 12 are different from each other, and therefore the inductance characteristics of the first core 11 and the second core 12 are different from each other. Therefore, simply changing the arrangement of the first core 11 and the second core 12 can change the inductance value (L value) and / or the DC superimposed current I ｓａｔ can be designed to meet the needs of individual users.

[0036] 1A to 1C, the conductor 20 may be in contact with the first core 11. Specifically, as shown in Fig. 1B and 1C, the upper surface of the linear portion 21 of the conductor 20 may be in contact with the first core 11. When the conductor 20 is in contact with the first core 11, the inductance value (L value) can be increased, as will be described in detail in the [Examples] section regarding inductance characteristics.

[0037] In a preferred embodiment of the inductor, the first magnetic particles 11p may be molded into the first core 11 by powder compaction in advance, and the first core, the conductor 20, and the second magnetic particles 12p that form the second core 12 may be formed by compression molding at a pressure lower than that used during powder compaction. As a result, the magnetic particle occupancy rate of the first core 11 may be higher than that of the second core 12. Specifically, the filling rate of the first magnetic particles 11p of the first core 11 may be higher than that of the second magnetic particles 12p of the second core 12. More specifically, the magnetic particle occupancy rate of the first core 11 may be 85% or more, and the magnetic particle occupancy rate of the second core 12 may be less than 85%. In this specification, the "filling rate" is measured as follows. First, the cross sections of the first core 11 and the second core 12 are exposed by polishing the inductor 1, FIB, cross-sectional ion milling, or the like, to form exposed surfaces. Thereafter, the first core 11 and the second core 12 are observed at 500 to 5000 magnifications using an SEM. Image analysis software WinROOF 2018 is used to process the image and extract the image portion of the voids, and the ratio of the total area of ​​the image portion of the voids to the area of ​​the cross section is calculated to measure the void ratio. In this embodiment, the magnetic particle occupancy rate of the first core 11 is higher than that of the second core 12, so the relative magnetic permeability of the first core 11 can be made higher than that of the second core 12, and the I of the first core 11 can be ｓａｔ Magnetic field of time H ｓａｔ is the I of the second core 12 ｓａｔ Magnetic field of time H ｓａｔ Therefore, by combining the first core 11 and the second core 12, a desired inductor can be designed to meet the needs of each individual user.

[0038] The difference in magnetic particle occupancy rate between the first core 11 and the second core 12 may be 1% or more. If the difference in magnetic particle occupancy rate between the first core 11 and the second core 12 is 1% or more, it is possible to combine the first core 11 and the second core 12 to design an inductor having a wide range of inductance characteristics.

[0039] The relative permeability of the first core 11 is equal to or greater than the relative permeability of the second core 12, and the H ｓａｔ is the H of the second core 12 ｓａｔ In this specification, "magnetic permeability" is measured as follows. Measurement was carried out using an LCR meter (4284A manufactured by Agilent Technologies). ｓａｔ " indicates the magnetic field [A / m] when the relative permeability decreases by 30%, and is measured as follows. H ｓａｔ In this embodiment, the relative permeability of the first core 11 is equal to or greater than the relative permeability of the second core 12, and the H ｓａｔ is H of the second core 12 ｓａｔ Therefore, by combining the first core 11 and the second core 12, a desired inductor can be designed to meet the needs of each individual user.

[0040] The difference between the relative permeability of the first core 11 and the relative permeability of the second core 12 may be 10 or more. If the difference between the relative permeabilities of the first core 11 and the second core 12 is 10 or more, it is possible to combine the first core 11 and the second core 12 to design an inductor having a wide range of inductance characteristics.

[0041] Second core H ｓａｔ and the first core H ｓａｔ The difference between the H ｓａｔ If the difference is 5000 A / m or more, it is possible to design an inductor having a wide range of inductance characteristics by combining the first core 11 and the second core 12.

[0042] As shown in FIG. 1D , the second magnetic particles 12p may include second magnetic large particles 12p1 and second magnetic small particles 12p2 having an average particle size smaller than that of the second magnetic large particles 12p1. Note that the term "average particle size" used herein refers to the particle size corresponding to a cumulative percentage of 50% on a volume basis. In this specification, "average particle size" is measured as follows: First, the cross sections of the first core 11 and the second core 12 are exposed by polishing the inductor 1, FIB, cross-sectional ion milling, or the like, to form exposed surfaces. Then, the first core 11 and the second core 12 are observed using an SEM at 500x to 5000x magnification. Image processing is performed using image analysis software WinROOF 2018 to determine the circle-equivalent diameter of each particle cross section. Then, assuming each particle is a sphere with a circle-equivalent diameter, the volume of each sphere is determined, and the average particle size can be calculated from the median of the volume distribution. In this embodiment, when the second core 12 contains second magnetic large particles 12p1 and second magnetic small particles 12p2, the second magnetic small particles 12p2 penetrate between the second magnetic large particles 12p1, thereby further increasing the filling rate of the second core 12, and by improving the filling rate, the relative permeability can be improved.

[0043] The second magnetic large particles 12p1 may have an average particle size of 15 μm or more and 30 μm or less. If the second magnetic large particles 12p1 have such an average particle size, the second core 12 can be sufficiently filled with the second magnetic large particles 12p1, improving the filling rate and the inductance characteristics.

[0044] The second magnetic small particles 12p2 may have an average particle size of 0.5 μm to 2 μm, inclusive, which allows the second magnetic small particles 12p2 to fit between the second magnetic large particles 12p1, thereby improving the filling rate of the second magnetic particles 12p in the second core 12 and enhancing the inductance characteristics.

[0045] The average particle size of the first magnetic particles 11p formed by powder compaction may be 2 μm or more and 20 μm or less. If the first magnetic particles have this average particle size, different inductance characteristics can be obtained with respect to the second core 12. Therefore, by combining the first core 11 and the second core 12, it is possible to design an inductor with a wide range of inductance characteristics.

[0046] More specifically, the average particle size of the first magnetic particles 11p may be less than the average particle size of the second magnetic large particles 12p1 and greater than or equal to the average particle size of the second magnetic small particles 12p2. When the average particle sizes of the first magnetic particles 11p, the second magnetic small particles 12p2, and the second magnetic large particles 12p1 satisfy the above-described relationship, the first core 11 and the second core 12 have different inductance characteristics, and by combining the first core 11 and the second core 12, it is possible to design inductors with a wide range of inductance characteristics.

[0047] In a preferred embodiment of the first core 11, the first core 11 may contain crystalline particles and / or amorphous particles. More preferably, the first core 11 may be crystalline particles. When crystalline particles are used for the first core 11, the crystalline particles have a relatively low hardness, which makes it easier to improve the filling rate by powder compaction, and the circularity can be preferably lower than that of the second magnetic particles 12p. Even when amorphous particles are used, the amorphous particles may be used for the first core 11 as long as the hardness can be lowered to a level that allows the circularity to be lower than that of the second magnetic particles 12p.

[0048] The inductor of this embodiment may be an inductor with low inductance characteristics, mainly having a relative permeability of 100 or less. Therefore, the inductor of this embodiment can be designed to meet the needs of individual users as an inductor with low inductance characteristics.

[0049] [Regarding Modifications of the Inductor of the First Embodiment] Next, Modifications 1 to 7 of the inductor of the first embodiment will be described with reference to Figures 2A to 8C. Note that in describing the inductors of Modifications 1 to 7, explanations of points common to the above description of [Regarding the Inductor of the First Embodiment] will be omitted as appropriate. In other words, the following description will focus on points that differ from the above description of [Regarding the Inductor of the First Embodiment].

[0050] -Modification 1 of the First Embodiment- In Modification 1, as shown in Figures 2A to 2C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in Figures 1A to 1C, the upper, lower and side surfaces of the wire portion 21 of the conductor 20 are in contact with the second core 12 (see, for example, Figure 2B). Furthermore, the conductor 20 is not in contact with the first core 11. With this inductor of Modification 1, compared to the inductor shown in Figures 1A to 1C, the inductance value (L value) can be designed to be lower by the amount that the conductor 20 is not in contact with the first core 11. On the other hand, the DC superimposed current I ｓａｔ The current value (at which the inductance value drops by 30% from the initial value) can be made higher compared to the inductors shown in FIGS. 1A to 1C.

[0051] -Modification 2 of First Embodiment- In Modification 2, as shown in Figures 3A to 3C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in Figures 1A to 1C, the side surface of the linear portion 21 in the conductor 20 contacts the second core 12 (see, for example, Figure 3B). Furthermore, the upper and lower surfaces of the linear portion 21 contact the first core 11 formed by powder compaction. In Modification 2, the first core 11 contacting the upper surface of the linear portion 21 and the first core 11 contacting the lower surface of the linear portion 21 are intended to be the same, but different cores may be used for the upper surface of the linear portion 21 and the lower surface of the linear portion 21 by varying the molding conditions in the powder compaction process or the first magnetic particles 11p used in the first core 11. 1A to 1C, the inductor of Modification 2 can be designed to have a larger inductance value (L value) because the contact area of ​​the first core 11 with which the conductor 20 comes into contact can be made larger. ｓａｔcan be lower compared to the inductors shown in FIGS. 1A-1C.

[0052] -Modification 3 of First Embodiment- In Modification 3, as shown in Figures 4A to 4C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in Figures 3A to 3C, the side and bottom surfaces of the wire portion 21 in the conductor 20 are in contact with the second core 12 (see, for example, Figure 4B). The top surface of the wire portion 21 is in contact with the first core 11 formed by powder compaction. With this inductor of Modification 3, the bottom surface of the conductor 20 is not in contact with the first core 11, so it is possible to design a lower inductance value (L value) compared to the inductor of Modification 2 shown in Figures 3A to 3C. On the other hand, the DC superimposed current I ｓａｔ can be made higher compared to the inductor of Modification 2 shown in FIGS. 3A to 3C.

[0053] -Fourth Modification of First Embodiment- In the fourth modification, as shown in Figures 5A to 5C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in Figures 4A to 4C, the side, upper, and lower surfaces of the wire portion 21 of the conductor 20 are in contact with the second core 12 (see, for example, Figure 5B). With the inductor of this fourth modification, the conductor 20 is not in contact with the first core 11, so it is possible to design a lower inductance value (L value) compared to the inductor of the third modification shown in Figures 4A to 4C. On the other hand, the DC superimposed current I ｓａｔ can be made higher compared to the inductor of Modification 3 shown in FIGS. 4A to 4C.

[0054] -Fifth Modification of First Embodiment- In the fifth modification, as shown in Figures 6A to 6C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in Figures 5A to 5C, the first core 11 is disposed around the entire periphery of the second core 12 (see, for example, Figure 6B). With this inductor of the fourth modification, compared to the inductor of the fourth modification shown in Figures 5A to 5C, the inductance value (L value) can be designed to be higher by the amount that the first core 11, which has a higher relative permeability than the second core 12, is disposed around the entire periphery of the second core 12. On the other hand, the DC superimposed current I ｓａｔcan be made lower compared to the inductor of Modification 4 shown in FIGS. 5A to 5C.

[0055] -Sixth Modification of First Embodiment- In the sixth modification, as shown in Figures 7A to 7C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in Figures 6A to 6C, the first core 11 is divided into two, and the second core 12 is interposed between the upper and lower first cores 11 (see, for example, Figure 7B). With the inductor of this sixth modification, compared to the inductor of the fifth modification shown in Figures 6A to 6C, the amount of the first core 11 with a high relative permeability is reduced and the amount of the second core 12 is increased, so that the inductance value (L value) can be designed to be low. On the other hand, the DC superimposed current I ｓａｔ can be made higher compared to the inductor of Modification 4 shown in FIGS. 6A to 6C.

[0056] -Seventh Modification of First Embodiment- In the seventh modification, as shown in Figures 8A to 8C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in Figures 7A to 7C, the upper surface of the wire portion 21 of the conductor 20 is in contact with the first core 11 (see, for example, Figure 8B). With the inductor of this seventh modification, the contact area of ​​the first core 11 with which the conductor 20 comes into contact can be made larger compared to the inductor of the sixth modification shown in Figures 7A to 7C, and therefore the inductance value (L value) can be designed to be larger. On the other hand, the DC superimposed current I ｓａｔ can be made lower compared to the inductor of Modification 6 shown in FIGS. 7A to 7C.

[0057] [Regarding the Inductor of the Second Embodiment] Next, an inductor of the second embodiment and its modified examples will be described with reference to Figures 9A to 19D. In describing the inductor of the second embodiment, explanation of points common to the above-mentioned [Regarding the Inductor of the First Embodiment] will be omitted as appropriate. In other words, the following description will focus on points that differ from the above-mentioned [Regarding the Inductor of the First Embodiment].

[0058] In the inductor of the second embodiment, when the conductor 20 is viewed in a plan view, two linear portions 21 extending in the L direction (see FIG. 9A ) are provided adjacent to each other in the W direction (see FIG. 9B ), and the ends of the linear portions 21 on the side of the second end surface 10d of the magnetic body 10 may be connected. Specifically, the conductor 20 may have a U-shape when viewed in a plan view. By making the shape of the conductor 20 U-shaped when viewed in a plan view, the length of the conductor portion can be made longer compared to the inductor of the first embodiment, and therefore the inductance value (L value) can be made larger.

[0059] 9A to 9C, the conductor 20 is embedded in the second core 12. The first core 11 is disposed on the bottom side of the second core 12. The first core 11 is not in contact with the conductor 20. Furthermore, electrode portions 22 extending toward the bottom surface (first main surface 10a in FIG. 9A) of the magnetic body 10 are provided corresponding to the two linear portions 21, respectively. As a result, the two electrode portions 22 are adjacent to each other when viewed from the first end surface 10c side, and are exposed when viewed from the first main surface 10a side.

[0060] Even in the inductor 1 of the second embodiment, the circularity of the first magnetic particles 11p contained in the first core 11 and the circularity of the second magnetic particles 12p contained in the second core 12 are different from each other, so the inductance characteristics of the first core 11 and the second core 12 are different from each other. Therefore, simply changing the arrangement of the first core 11 and the second core 12 can change the inductance value (L value) and / or the DC superimposed current I ｓａｔ can be designed to meet individual user requirements.

[0061] Variation 1 of the Second Embodiment In Variation 1, as shown in Figures 10A to 10C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in Figures 9A to 9C, the side surface of the linear portion 21 in the conductor 20 contacts the second core 12 (see, for example, Figure 10B). Furthermore, the upper and lower surfaces of the linear portion 21 contact the first core 11 formed by powder compaction. In Variation 1, the first core 11 contacting the upper surface of the linear portion 21 and the first core 11 contacting the lower surface of the linear portion 21 are intended to be the same, but different cores may be used for the upper surface of the linear portion 21 and the lower surface of the linear portion 21 by varying the molding conditions in the powder compaction process or the first magnetic particles 11p used in the first core 11. 9A to 9C, the inductor of the first modification example can be designed to have a larger inductance value (L value) because the contact area between the conductor 20 and the first core 11 can be made larger. ｓａｔ can be lower compared to the inductors shown in FIGS. 9A-9C.

[0062] 11A to 11C, in Modification 2, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in FIGS. 10A to 10C, the side and top surfaces of the wire portion 21 in the conductor 20 are in contact with the second core 12 (see, for example, FIG. 11B). The bottom surface of the wire portion 21 is in contact with the first core 11 formed by powder compaction. With this inductor in Modification 2, the top surface of the conductor 20 is not in contact with the first core 11, so it is possible to design a lower inductance value (L value) compared to the inductor in Modification 1 shown in FIGS. 10A to 10C. On the other hand, the DC superimposed current I ｓａｔ can be made higher compared to the inductor of Modification 1 shown in FIGS. 10A to 10C.

[0063] Modification 3 of the Second Embodiment In Modification 3, as shown in Figures 12A to 12C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in Figures 11A to 11C, the inner side surface and upper surface of the wire portion 21 of the conductor 20 are in contact with the second core 12 (see, for example, Figure 12B). Also, the outer side surface and lower surface of the wire portion 21 of the conductor 20 are in contact with the first core 11. With this inductor of Modification 3, compared to the inductor of Modification 2 shown in Figures 11A to 11C, the outer side surface and lower surface of the conductor 20 are in contact with the first core 11, so it is possible to design a higher inductance value (L value). On the other hand, ｓａｔ can be made lower compared to the inductor of Modification 2 shown in FIGS. 11A to 11C.

[0064] Variation 4 of the Second Embodiment In Variation 4, as shown in FIGS. 13A to 13C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in FIGS. 12A to 12C, the inner side surface of the wire portion 21 of the conductor 20 contacts the second core 12 (see, for example, FIG. 13B). Furthermore, the outer side surface, upper surface, and lower surface of the wire portion 21 of the conductor 20 contact the first core 11. With the inductor of Variation 4, the outer side surface, upper surface, and lower surface of the conductor 20 contact the first core 11, so that the inductance value (L value) can be designed to be higher than in the inductor of Variation 3 shown in FIGS. 12A to 12C. On the other hand, the DC superimposed current I ｓａｔ can be made lower compared to the inductor of Modification 3 shown in FIGS. 12A to 12C.

[0065] 14A to 14C, in the fifth modification, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in FIGS. 13A to 13C, the inner and outer side surfaces of the wire portion 21 of the conductor 20 are in contact with the second core 12. Furthermore, the upper and lower surfaces of the wire portion 21 of the conductor 20 are in contact with the first core 11 (see, for example, FIG. 14B). With the inductor of the fifth modification, the inner and outer side surfaces of the conductor 20 are not in contact with the first core 11, so that the inductance value (L value) can be designed to be lower compared to the inductor of the fourth modification shown in FIGS. 13A to 13C. On the other hand, the DC superimposed current I ｓａｔ can be made higher compared to the inductor of Modification 4 shown in FIGS. 13A to 13C.

[0066] Modification 6 of Second Embodiment In Modification 6, as shown in FIGS. 15A to 15C, the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment in FIGS. 14A to 14C, the second core 12 is interposed between the upper first core 11 and the lower first core 11 (see, for example, FIG. 15B). The conductor 20 is in contact with the second core 12, but not with the first core 11. With the inductor of Modification 6, the amount of the first core 11 with a high relative permeability is reduced and the amount of the second core 12 is increased, compared to the inductor of Modification 5 shown in FIGS. 14A to 14C, so the inductance value (L value) can be designed to be low. On the other hand, the DC superimposed current I ｓａｔ can be made higher compared to the inductor of Modification 5 shown in FIGS. 14A to 14C.

[0067] Variation 7 of the Second Embodiment In Variation 7, as shown in FIGS. 16A to 16D , the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in FIGS. 9A to 9C , the lower surface of the linear portion 21 of the conductor 20 does not contact the second core 12 (see, for example, FIG. 16B ). Specifically, the lower surface of the linear portion 21 contacts the first core 11. Furthermore, in Variation 7, as shown in FIGS. 16A to 16D , the two linear portions 21 are connected at the sides of the second end face 10d of the magnetic body 10, and electrode portions 22 are provided on both the end of the linear portion 21 on the first end face 10c side of the magnetic body 10 and the end on the second end face 10d side. Specifically, when the inductor is viewed from the first main surface 10a side of the magnetic body 10, four electrode portions 22 are exposed (see, for example, FIG. 16C ). In the inductor of variant example 7, four electrode portions 22 are exposed, and therefore, compared to the form in which two electrode portions 22 are exposed as in Figures 9A to 9C, the inductor is mounted on the substrate using four electrode portions 22, thereby improving the reliability of the mounting.

[0068] Modifications 8 and 9 of the Second Embodiment In Modification 8, as shown in FIGS. 17A to 17D , the conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in FIGS. 16A to 16D , the upper surfaces of the four electrode portions 22 are covered by the second core 12 (see, for example, FIG. 17C ). With this inductor according to Modification 8, the electrode portions 22 are less exposed from the second core 12 than in the embodiment shown in FIGS. 16A to 16D , thereby reducing unintended short circuits of the electrode portions 22. Note that, as shown in Modification 9 shown in FIGS. 18A to 18D , the first core 11 may be completely covered by the second core 12 (see, for example, FIGS. 18B and 18C ). Furthermore, the side surfaces of the electrode portions 22 facing each other in the L direction may be in contact with the second core 12.

[0069] Modification 10 of the Second Embodiment In Modification 10, as shown in FIGS. 19A to 19D , the first core 11 is divided into two parts in the W direction. Specifically, in the cross-sectional view shown in FIG. 19B , the first core 11 extends from the top surface of the inductor 1 to the side and bottom surfaces. More specifically, the first core 11 is arranged to have a U-shape in the cross-sectional view, and the second core 12 is interposed between the first cores 11 in the W direction. The conductor 20 is embedded in the second core 12. Specifically, unlike the embodiment shown in FIGS. 13A to 13C , the top surface, bottom surface, and inner side surface of the conductor 20 are in contact with the second core 12, but the outer side surface of the conductor 20 is not in contact with the second core 12. Specifically, the outer side surface of the conductor 20 is in contact with the first core 11. 13A to 13C, the inductor of Modification 9 has a reduced amount of first core 11 with a high relative permeability, an increased amount of second core 12, and a smaller contact area between conductor 20 and first core 11, so that the inductance value (L value) can be designed to be low. ｓａｔ can be made higher compared to the inductor of Modification 4 shown in FIGS. 13A to 13C.

[0070] [Regarding the Inductor of the Third Embodiment] Next, the inductor of the third embodiment and its modified examples will be described with reference to Figures 20A to 22C. In describing the inductor of the third embodiment, the description of points common to the above description of [Regarding the Inductor of the First Embodiment] will be omitted as appropriate. In other words, the following description will focus on points that are different from the above description of [Regarding the Inductor of the First Embodiment].

[0071] The inductor of the third embodiment may be wound around the conductor 20 when viewed in plan. In the configuration shown in Figures 20A to 20C, the conductor 20 is wound once (see, for example, Figure 20A), but this is not limiting and the conductor may be wound one or more times, or one or less times (for example, 0.75 times). By forming the conductor 20 into a wound shape when viewed in plan, the length of the conductor portion can be made longer than in the inductor of the second embodiment, and the winding can increase the inductance value (L value).

[0072] 20A to 20C, the inductor 1 may have the first core 11 covered by the second core 12. Specifically, the volume of the first core 11 may be larger than the volume of the second core 12. The conductor 20 may be embedded in the second core 12. As shown in FIGS. 20A to 20C, the conductor 20 is formed by winding a conductor and has a sloped winding portion 21a, an upper electrode portion 22 electrically connected to an upper end of the winding portion 21a in the H direction, and a lower electrode portion 22 electrically connected to a lower end of the winding portion 21a in the H direction. In plan view, as shown in a cross-sectional view (see FIG. 20B) taken along a line parallel to the W direction (see FIG. 20A) and along a pair of electrode portions 22, winding portion 21a electrically connected to lower electrode portion 22 is in contact with first core 11, while winding portion 21a electrically connected to upper electrode portion 22 is not in contact with first core 11. Furthermore, in plan view, as shown in a cross-sectional view (see FIG. 20C) taken along a line parallel to the W direction (see FIG. 20A) and passing through the center of winding portion 21a, lower winding portion 21a and upper winding portion 21a are not in contact with first core 11.

[0073] Even in the inductor 1 of the third embodiment, the circularity of the first magnetic particles 11p contained in the first core 11 and the circularity of the second magnetic particles 12p contained in the second core 12 are different from each other, and therefore the inductance characteristics of the first core 11 and the second core 12 are different from each other. Therefore, simply changing the arrangement of the first core 11 and the second core 12 can change the inductance value (L value) and / or the DC superimposed current I ｓａｔcan be designed to meet individual user requirements.

[0074] Modification 1 of the Third Embodiment In Modification 1, as shown in FIGS. 21A to 21C , the first core 11 is disposed above the second core 12. Specifically, unlike the embodiment in FIGS. 20A to 20C , the second core 12 is sandwiched between the first cores 11 (see, for example, FIGS. 21B and 21C ). In the conductor 20, the winding portion 21 a electrically connected to the upper electrode portion 22 contacts the upper first core 11. Furthermore, the winding portion 21 a electrically connected to the lower electrode portion 22 contacts the lower first core 11. In Modification 1, the upper first core 11 and the lower first core 11 are intended to be the same, but the first core 11 and the second core 12 may be different by varying the molding conditions in the powder compacting process or the first magnetic particles 11p used in the first core 11. 20A to 20C, the inductor of Modification 1 can be designed to have a larger inductance value (L value) because the contact area of ​​the first core 11 with the conductor 20 can be made larger. ｓａｔ can be lower compared to the inductors shown in FIGS. 20A-20C.

[0075] Variation 2 of the Third Embodiment As shown in FIGS. 22A to 22C , Variation 2 differs from the inductor shown in FIGS. 20A to 20C in that, in a plan view, as shown in a cross-sectional view (see FIG. 22C ) cut along a line parallel to the W direction (see FIG. 22A ) and passing through the center of the winding portion 21a, the lower winding portion 21a is in contact with the first core 11, while the upper winding portion 21a is not in contact with the first core 11. This configuration is intended to increase the inductance value (L value) by taking into account that the conductor 20 is inclined like a slope, and to increase the contact area of ​​the conductor 20 with the first core 11 as much as possible. With this inductor of Variation 2, the contact area of ​​the conductor 20 with the first core 11 can be increased compared to the inductor shown in FIGS. 20A to 20C , allowing for a larger inductance value (L value). On the other hand, the DC superimposed current I ｓａｔ can be lower compared to the inductors shown in FIGS. 20A-20C.

[0076] [Regarding the Inductor of the Fourth Embodiment] Next, the inductor of the fourth embodiment and its modified examples will be described with reference to Figures 23A to 27C. In describing the inductor of the fourth embodiment, explanation of points common to the above-mentioned [Regarding the Inductor of the First Embodiment] will be omitted as appropriate. In other words, the following description will focus on points that differ from the above-mentioned [Regarding the Inductor of the First Embodiment].

[0077] In the inductor of the fourth embodiment (see FIGS. 23A to 23C ), compared to the inductor shown in FIG. 1 , the electrode portion 22 at one end of the linear portion 21 of the conductor 20 in the L direction (see FIG. 23A ) extends toward the +H direction, and the electrode portion 22 at the other end of the linear portion 21 in the L direction extends toward the −H direction. This inductor of the fourth embodiment allows for three-dimensional electrical wiring via the inductor. Specifically, by embedding the inductor of the fourth embodiment in a laminated substrate having electrodes stacked one on top of the other, the electrode portion 22 extending in the +H direction can be electrically connected to an upper electrode of the laminated substrate (not shown), and the electrode portion 22 extending in the −H direction can be electrically connected to a lower electrode of the laminated substrate (not shown). It is also possible to electrically connect the inductor of this embodiment so that it is sandwiched between upper and lower substrates. For example, it is possible to electrically connect the electrode portion 22 extending in the +H direction with respect to the upper substrate (not shown) and electrically connect the electrode portion 22 extending in the -H direction with respect to the lower substrate (not shown).

[0078] -Modification 1 of Fourth Embodiment- Modification 1 (see FIGS. 24A to 24C) differs from the embodiment shown in FIGS. 23A to 23C in that the second core 12 is sandwiched between the first cores 11 in the H direction (see FIG. 23B) (see, for example, FIG. 24B). Specifically, the first cores 11 are disposed above and below the second core 12. The upper and lower surfaces of the linear portion 21 are in contact with the first core 11 formed by powder compaction, and the side surfaces of the linear portion 21 may be in contact with the second core 12. In Modification 1, the first core 11 in contact with the upper surface of the linear portion 21 and the first core 11 in contact with the lower surface of the linear portion 21 are intended to be the same. However, different cores may be used for the upper surface of the linear portion 21 and the lower surface of the linear portion 21 by varying the molding conditions in the powder compaction process or the first magnetic particles 11p used in the first core 11. 23A to 23C, the inductor of Modification 1 can be designed to have a larger inductance value (L value) because the contact area of ​​the first core 11 with the conductor 20 can be made larger. ｓａｔ 23A to 23C. Furthermore, three-dimensional electrical wiring can be achieved via the electrode portions 22 extending in the ±H directions in the inductor of Modification 1.

[0079] Modification 2 of the Fourth Embodiment Modification 2 (see FIGS. 25A to 25C) differs from the embodiment shown in FIGS. 24A to 24C in that the side and bottom surfaces of the wire portion 21 of the conductor 20 are in contact with the second core 12 (see, for example, FIG. 25B). The top surface of the wire portion 21 is in contact with the first core 11 formed by powder compaction. With the inductor of Modification 2, the bottom surface of the conductor 20 is not in contact with the first core 11, so that the inductance value (L value) can be designed to be lower than in the inductor shown in FIGS. 24A to 24C. On the other hand, the DC superimposed current I ｓａｔ 24A to 24C. Furthermore, three-dimensional electrical wiring can be achieved via the electrode portions 22 extending in the ±H directions in the inductor of Modification 2.

[0080] Modification 3 of the Fourth Embodiment In Modification 3 (see FIGS. 26A to 26E), when viewed from above, the conductor 20 includes two linear portions 21 extending in the L direction (see FIG. 26A), with the ends of the linear portions 21 connected to each other on the second end face 10d side. An electrode portion 22 extends from the end of one linear portion 21 on the first end face 10c side toward the +H direction, while an electrode portion extends from the end of the other linear portion 21 on the first end face 10c side toward the -H direction. This type of conductor 20 allows for a larger inductance value (L value) than the inductor shown in FIGS. 23A to 23C. Furthermore, three-dimensional electrical wiring can be achieved via the electrode portions 22 extending in the ±H directions in the inductor of Modification 3.

[0081] Variation 4 of the Fourth Embodiment Variation 4 (see FIGS. 27A to 27C) may have a winding shape when viewed in plan. One end of the winding portion 21a has an electrode portion 22 extending in the +H direction, and the other end of the winding portion 21a has an electrode portion 22 extending in the −H direction. Such a winding conductor 20 in plan view can have a larger inductance value (L value) than the inductor shown in FIGS. 23A to 23C. Furthermore, three-dimensional electrical wiring can be achieved via the electrode portions 22 extending in the ±H directions in the inductor of Variation 4.

[0082] [Regarding the Inductor of the Fifth Embodiment] Next, the inductor of the fifth embodiment and its modified examples will be described with reference to Figures 28A to 31D. In describing the inductor of the fifth embodiment, the description of points common to the above-mentioned [Regarding the Inductor of the First Embodiment] will be omitted as appropriate. In other words, the following description will focus on points that differ from the above-mentioned [Regarding the Inductor of the First Embodiment].

[0083] The inductor 1 shown in Figures 28A to 28D has multiple conductors 20 embedded in the second core 12. In the illustrated example, two conductors 20 are embedded in the second core 12. A first core 11 formed by powder compaction is placed between two conductors 20 adjacent to each other in the W direction (see, for example, Figure 28B). Because the magnetic flux density is lowest between the two conductors 20, placing the first core 11 at this position can increase the inductance value (L value). Note that the number of conductors 20 is not limited to two; for example, four conductors may be provided, as shown in Figures 29A to 29D.

[0084] Variation 1 of the Fifth Embodiment Variation 1 (FIGS. 30A to 30C) provides three-dimensional wiring for the inductor shown in FIGS. 28A to 28D. The electrode portion 22 at one end of the linear portion 21 of one conductor 20 in the L direction extends toward the +H direction, while the electrode portion 22 at the other end of the linear portion 21 in the L direction extends toward the −H direction. The electrode portion 22 at one end of the linear portion 21 of the other conductor 20 in the L direction extends toward the −H direction, while the electrode portion 22 at the other end of the linear portion 21 in the L direction extends toward the +H direction. In other words, the arrangement of one conductor 20 and the other conductor 20 may be staggered. As used herein, "staggered" refers to a relationship in which one conductor 20 is rotated 180 degrees relative to the other conductor 20. The inductor of Variation 1 allows three-dimensional electrical wiring via the electrode portions 22 extending in the ±H directions. When four conductors 20 are provided, the adjacent conductors 20 may be arranged alternately as shown in FIGS. 31A to 31C.

[0085] [Method for Manufacturing Inductor] Next, a method for manufacturing an inductor according to the present disclosure will be described with reference to Fig. 32. The method for manufacturing an inductor according to the present disclosure includes a step of molding a first core, a step of arranging a conductor, a step of arranging a second magnetic material, and a compression molding step. Each step will be described below.

[0086] Step of Molding First Core: A first magnetic material is prepared for manufacturing the first core 11. For example, particles of one or more metallic magnetic materials selected from the group consisting of crystalline particles such as an alloy containing Fe and Ni, an alloy containing Fe and Co, an alloy containing Fe and Si, an alloy containing Fe, Si and Cr, an alloy containing Fe, Si and Al, amorphous particles such as an alloy containing Fe, Si, B and Cr, and an alloy containing Fe, P, Cr, Si, B, Nb and C are prepared.

[0087] An insulating coating is applied to the first magnetic particles. The insulating coating is formed by a sol-gel reaction of a metal alkoxide and / or a mechanochemical method. The insulating coated first magnetic particles are mixed with a first resin (e.g., a thermosetting resin) to prepare a first magnetic material for manufacturing the first core 11.

[0088] The prepared first magnetic material is filled into a molding die, and the first magnetic material is heated and pressurized in the molding die. Specifically, the first magnetic material is powder-molded. Here, the first magnetic particles in the first magnetic material are compressed to a density of 10 t / mm to achieve a circularity of less than 0.9. ２ The first magnetic particles are compressed at a pressure of 10 t / mm or more. Therefore, the circularity of the first magnetic particles becomes relatively small. ２ As a result, the first magnetic material is thermally hardened in the molding die, and the first core 11 can be manufactured.

[0089] After the first core 11 is manufactured in advance, the conductor 20 is arranged on the first core 11. The conductor 20 arranged on the first core 11 may be a rectangular wire or a round wire. The conductor may be linear as in the first embodiment, U-shaped as in the second embodiment, or wound as in the third embodiment.

[0090] Step of disposing second magnetic material: A second magnetic material is prepared for manufacturing the second core 12. For example, particles of one or more metallic magnetic materials selected from the group consisting of crystalline particles such as an alloy containing Fe and Ni, an alloy containing Fe and Co, an alloy containing Fe and Si, an alloy containing Fe, Si and Cr, an alloy containing Fe, Si and Al, amorphous particles such as an alloy containing Fe, Si, B and Cr, and an alloy containing Fe, P, Cr, Si, B, Nb and C are prepared.

[0091] An insulating coating is applied to the second magnetic particles. The insulating coating is formed by a sol-gel reaction of a metal alkoxide and / or a mechanochemical method. The insulating coated second magnetic particles are mixed with a second resin (e.g., a thermosetting resin) to prepare a second magnetic material for manufacturing the second core 12. To increase the filling rate of the second core 12, two types of second magnetic particles may be used: second magnetic small particles 12p2 having a relatively small average particle size and second magnetic large particles 12p1 having an average particle size larger than that of the second magnetic small particles 12p2. Instead of using two types of second magnetic particles, one type may be used, or two or more types may be used.

[0092] Compression molding process: The prepared second magnetic material is filled into the molding die so as to bury the conductor 20 arranged relative to the first core 11. Then, the first core 11, the conductor 20, and the second magnetic material are heated and pressurized together in the molding die. The pressure applied to the second magnetic material is lower than the pressure applied when the first magnetic material is powder-molded (for example, 200 kg / mm). ２ 1t / mm or more ２ The "compression molding" in this specification refers to a process in which the pressure is 200 kg / mm ２ 1t / mm or more ２ It is intended to be formed as follows:

[0093] As described above, the inductor manufacturing method of the present disclosure can manufacture a magnetic body including a first core 11 containing first magnetic particles and a second core 12 containing second magnetic particles having a greater circularity than the first magnetic particles, and an inductor in which at least a portion of a conductor 20 is embedded in the second core 12. Furthermore, according to the inductor 1 of the present disclosure, the circularity of the first magnetic particles 11p contained in the first core 11 differs from the circularity of the second magnetic particles 12p contained in the second core 12, and therefore the inductance characteristics of the first core 11 and the second core 12 differ from each other. Therefore, the inductance value (L value) and / or the DC superimposed current I can be changed simply by changing the arrangement of the first core 11 and the second core 12, etc. ｓａｔ It is possible to design inductors that meet the needs of individual users.

[0094] The magnetic material of the present disclosure was subjected to the following verification tests. Specifically, the inductors of Examples 1-1 to 1-8 shown below were manufactured.

[0095] The aspects of the inductors relating to Examples 1-1 to 1-8 are as follows: Example 1-1: Inductor shown in Figs. 1A to 1C. Example 1-2: Inductor shown in Figs. 2A to 2C. Example 1-3: Inductor shown in Figs. 3A to 3C. Example 1-4: Inductor shown in Figs. 4A to 4C. Example 1-5: Inductor shown in Figs. 5A to 5C. Example 1-6: Inductor shown in Figs. 6A to 6C. Example 1-7: Inductor shown in Figs. 7A to 7C. Example 1-8: Inductor shown in Figs. 8A to 8C.

[0096] The magnetic materials used in Examples 1-1 to 1-8 are as follows: First core: First metal magnetic particles: Fe—Si-based metal magnetic material First insulating coating: tetraethoxysilane Average particle size: 15 μm Second core: Second metal magnetic particles: Large particles: Fe—Si-based metal magnetic material, Small particles: Fe-based metal magnetic material Second insulating coating: zinc phosphate or tetraethoxysilane Average particle size of second metal magnetic small particles: 3.0 μm Average particle size of second metal magnetic large particles: 22.5 μm Ratio of second metal magnetic small particles to second metal magnetic large particles: 7:3

[0097] The inductance characteristics were measured for Examples 1-1 to 1-8. ｓａｔ The inductance value L was measured using an LCR meter (4284A manufactured by Agilent Technologies).

[0098] Measured I ｓａｔ and the inductance value L are as shown in Fig. 33. As described above, according to the inductor of the present disclosure, the circularity of the first magnetic particles 11p contained in the first core 11 and the circularity of the second magnetic particles 12p contained in the second core 12 are different from each other, and therefore the inductance characteristics of the first core 11 and the second core 12 are different from each other. Therefore, simply changing the arrangement of the first core 11 and the second core 12 can change the inductance value (L value) and / or the DC superimposed current I ｓａｔ It is possible to design inductors that meet the needs of individual users.

[0099] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. The technical scope of the present disclosure also includes all modifications within the scope and meaning equivalent to the claims.

[0100] The inductor and the method for manufacturing the inductor according to the present disclosure are as follows: <1> An inductor comprising: a magnetic body; and a conductor provided in the magnetic body, wherein the magnetic body includes a first core including first magnetic particles and a second core including second magnetic particles having a greater circularity than the first magnetic particles, wherein the first core and the second core are in contact with each other, and at least a portion of the conductor is embedded in the second core. <2> The inductor according to <1>, wherein the conductor is in contact with the first core. <3> The inductor according to <1>, wherein the conductor is not in contact with the first core. <4> The relative permeability of the first core is equal to or greater than the relative permeability of the second core, and the H of the first core is ｓａｔ is the H of the second core ｓａｔ<5> The inductor according to any one of <1> to <4>, wherein the difference between the relative permeability of the first core and the relative permeability of the second core is 10 or more. <6> The inductor according to any one of <1> to <4>, wherein the difference between the relative permeability of the first core and the relative permeability of the second core is 10 or more. ｓａｔ and H of the second core ｓａｔ The inductor according to any one of <1> to <5>, wherein the difference between the resistance and the resistance of the conductor is 5000 A / m or more. <7> The inductor according to any one of <1> to <6>, wherein the conductor has an insulating coating on its surface. <8> The inductor according to any one of <1> to <7>, wherein the first core includes crystalline particles and / or amorphous particles. <9> The inductor according to any one of <1> to <8>, wherein the second magnetic particles include second magnetic large particles and second magnetic small particles having an average particle size smaller than that of the second magnetic large particles. <10> The inductor according to any one of <1> to <9>, wherein the average particle size of the first magnetic particles is 2 μm or more and 20 μm or less. <11> The inductor according to <9> or <10>, wherein the average particle size of the second magnetic large particles is 15 μm or more and 30 μm or less. <12> The inductor according to any one of <9> to <11>, wherein the average particle size of the second magnetic small particles is 0.5 μm or more and 2 μm or less. <13> The inductor according to any one of <9> to <12>, wherein the average particle size of the first magnetic particles is less than the average particle size of the second magnetic large particles and is equal to or greater than the average particle size of the second magnetic small particles. <14> The inductor according to any one of <1> to <13>, wherein the magnetic particle occupancy of the first core is 85% or more, and the magnetic particle occupancy of the second core is less than 85%. <15> The inductor according to <14>, wherein the difference between the magnetic particle occupancy of the first core and the magnetic particle occupancy of the second core is 1% or more. <16> The inductor according to any one of <1> to <15>, wherein the relative permeability is 100 or less. <17> A method for manufacturing an inductor, comprising: a step of compacting a first magnetic material containing first magnetic particles and a first resin to form a first core; a step of arranging a conductor on the first core; a step of arranging a second magnetic material containing second magnetic particles and a second resin on the conductor; and a step of compression molding the first core, the conductor, and the second magnetic material at a pressure lower than the pressure used during the compacting.

[0101] The inductor disclosed herein has an inductance value (L value) and a DC superimposed current I that meet the needs of individual users. ｓａｔ The present invention can be suitably used as an electronic component that increases the degree of freedom in design.

[0102] REFERENCE SIGNS LIST 1 inductor 10 magnetic body 10a first main surface 10b second main surface 10c first end surface 10d second end surface 10e first side surface 10f second side surface 11 first core 11p first magnetic particle 12 second core 12p second magnetic particle 12p1 second magnetic large particle 12p2 second magnetic small particle 20 conductor 21 wire portion 21a winding portion 22 electrode portion

Claims

1. An inductor comprising a magnetic body and a conductor provided in the magnetic body, wherein the magnetic body includes a first core containing first magnetic particles and a second core containing second magnetic particles having a circularity greater than that of the first magnetic particles, the first core and the second core are in contact with each other, and at least a part of the conductor is embedded in the second core.

2. The inductor according to claim 1, wherein the conductor is in contact with the first core.

3. The inductor according to claim 1, wherein the conductor is not in contact with the first core.

4. The relative permeability of the first core is equal to or greater than that of the second core, and the H of the first core ｓａｔ is the H of the second core ｓａｔ is smaller than that of the second core. The inductor according to any one of claims 1 to 3.

5. The inductor according to any one of claims 1 to 4, wherein the difference between the relative permeability of the first core and the relative permeability of the second core is 10 or more.

6. The H of the first core ｓａｔ and the H of the second core ｓａｔ The inductor according to any one of claims 1 to 5, wherein the difference therebetween is 5000 A / m or more.

7. The inductor according to any one of claims 1 to 6, wherein the conductor has an insulating coating on its surface.

8. The inductor according to any one of claims 1 to 7, wherein the first core includes crystalline particles and / or amorphous particles.

9. The inductor according to any one of claims 1 to 8, wherein the second magnetic particles include second large magnetic particles and second small magnetic particles having an average particle diameter smaller than that of the second large magnetic particles.

10. The inductor according to any one of claims 1 to 9, wherein the average particle diameter of the first magnetic particles is 2 μm or more and 20 μm or less.

11. The inductor according to claim 9 or 10, wherein the average particle diameter of the second large magnetic particles is 15 μm or more and 30 μm or less.

12. The inductor according to any one of claims 9 to 11, wherein the average particle diameter of the second small magnetic particles is 0.5 μm or more and 2 μm or less.

13. The inductor according to any one of claims 9 to 12, wherein the average particle diameter of the first magnetic particles is less than the average particle diameter of the second large magnetic particles and is equal to or more than the average particle diameter of the second small magnetic particles.

14. The inductor according to any one of claims 1 to 13, wherein the magnetic particle occupancy of the first core is 85% or more, and the magnetic particle occupancy of the second core is less than 85%.

15. The inductor according to claim 14, wherein the difference between the magnetic particle occupancy of the first core and the magnetic particle occupancy of the second core is 1% or more.

16. The inductor according to any one of claims 1 to 15, having a relative permeability of 100 or less.

17. A method for manufacturing an inductor, comprising: a step of compacting a first magnetic material including first magnetic particles and a first resin to form a first core; a step of disposing a conductor with respect to the first core; a step of disposing a second magnetic material including second magnetic particles and a second resin with respect to the conductor; and a step of compression molding the first core, the conductor, and the second magnetic material at a pressure lower than the pressure during the compacting.

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