Coil components and power supply devices

Abstract

A coil component, comprising a core portion including soft magnetic metal particles and a resin, and a winding portion formed by winding a conductor, wherein the coil component is formed by the winding portion being formed inside the core portion. The winding portion has an inner peripheral surface, an outer peripheral surface, and an end surface. The core portion has a core central region and a region near the coil corner, wherein the core central region is located within a region within a specified range from the center of the winding axis toward the perpendicular outer direction, and the region near the coil corner is within a specified range from the coil corner where the inner peripheral surface and the end surface intersect. The soft magnetic metal particles contain specific particles with a particle size of 10 μm or more and 50 μm or less, and the average inter-particle distance of the specific particles in the core central region is set to D1, and the average inter-particle distance of the specific particles in the region near the coil corner is set to D2, and 0<D1 / D2<1.00.

Description

Technical Field

[0001] The present disclosure relates to a coil component and a power supply device. Background Art

[0002] Patent Document 1 describes that since the uniformity of the interior of a molded body obtained by pressure-molding composite magnetic particles is improved, the DC superposition characteristics of a reactor using the molded body as a core are improved.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-070885 Summary of the invention

[0006] Problems to be solved by the invention

[0007] The present invention provides a coil component having high inductance and DC superposition characteristics.

[0008] Due to the technical solution to the problem

[0009] To achieve the above object, the present disclosure provides a coil component having a core portion including soft magnetic metal particles and a resin, and a winding portion formed by winding a conductor, wherein the winding portion is formed inside the core portion, wherein:

[0010] The winding portion has an inner peripheral surface, an outer peripheral surface, and an end surface.

[0011] The core portion has a central core area and an area near the coil corner, the central core area is located within a specified range from the center of the winding axis toward the vertical outer side, and the distance between the area near the coil corner and the coil corner where the inner peripheral surface and the end surface intersect is within a specified range,

[0012] The soft magnetic metal particles contain specific particles with a particle size of not less than 10 μm and not more than 50 μm, the average inter-particle distance of the specific particles in the central area of ​​the core is set to D1, and the average inter-particle distance of the specific particles in the area near the coil corner is set to D2, 0<D1 / D2<1.00.

[0013] The power supply device of the present disclosure includes the above-mentioned coil component. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a cross section of an inductor according to an example of the present embodiment.

[0015] Figure 2 It is along Figure 1 Schematic diagram of the cross section of line II.

[0016] Figure 3 yes Figure 1 Enlarged view of the main part.

[0017] Figure 4 This is a schematic diagram showing the positional relationship of each component before thermocompression bonding used in the process of manufacturing the inductor according to an example of the present embodiment.

[0018] Figure 5 This is a schematic diagram showing the positional relationship of each component before thermocompression bonding used in the process of manufacturing the inductor according to an example of the present embodiment. DETAILED DESCRIPTION

[0019] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. The embodiment of the present disclosure described below is an example for illustrating the present disclosure. Various components of an embodiment of the present disclosure, such as numerical values, shapes, materials, manufacturing processes, etc., can be changed or altered within the scope that does not cause technical problems.

[0020] In addition, the shapes and the like shown in the drawings of the present disclosure do not necessarily correspond to the actual shapes and the like, and the shapes and the like may be changed for the purpose of explanation.

[0021] Figure 1 This is a cross section passing through the winding axis center 4α of the winding portion 4 and parallel to the winding axis center 4α. Figure 2 It is along Figure 1 Schematic diagram of the cross section of the I-I line. Figure 1 , Figure 2 As shown in FIG. 1 , an inductor 2 as a type of coil component according to an embodiment of the present disclosure includes a winding portion 4 and a core portion 6. The winding portion 4 is formed by winding a conductor 5 in a coil shape.

[0022] In the inductor 2 of one embodiment of the present disclosure, the upper and lower surfaces of the core 6 are perpendicular to the Z axis, and the side surfaces of the core 6 are perpendicular to the plane including the X axis and the Y axis. In addition, the winding axis of the winding portion 4 is parallel to the Z axis. However, the shape of the core 6 is not limited to Figure 1 , Figure 2 shape.

[0023] In addition, the term "parallel" in the present disclosure includes not only completely parallel but also substantially parallel. That is, the term "parallel" in the present disclosure may include an error within the range of manufacturing tolerance, or may include an error beyond the range of manufacturing tolerance. Specifically, the term "line A and line B are parallel" means that the angle formed by line A and line B is greater than 0° and less than 10° unless otherwise specified. The same applies to replacing one or two lines with a plane.

[0024] In addition, the term "perpendicular" in the present disclosure includes not only completely perpendicular but also substantially perpendicular. That is, the term "perpendicular" in the present invention may include an error within the range of manufacturing tolerance, or may include an error beyond the range of manufacturing tolerance. Specifically, the term "perpendicular" between line A and line B means that the angle between line A and line B is greater than 80° and less than 100° unless otherwise specified. The same applies to replacing one or two lines with a plane.

[0025] The size of the inductor 2 of the embodiment of the present disclosure is not particularly limited. The lower limit of the size of the portion other than the portion not shown (e.g., the lead portion and the terminal described later) may be the size of a rectangular parallelepiped with a bottom of 2 mm × 2 mm and a height of 1 mm. The upper limit of the size of the portion other than the portion not shown may be the size of a cube with a bottom of 25 mm × 25 mm and a height of 25 mm. The height is Figure 1 The length in the Z-axis direction. Figure 1 , Figure 2 In the figure, the lead wire part, the terminal, etc. of the winding part 4 are omitted. The lead wire part may be formed at both ends of the conductor which comprises the winding part 4, and may be taken out to the outside of the core part 6.

[0026] The conductor (conducting wire) 5 constituting the winding portion 4 is coated with an insulating coating layer as required. The material of the conductor 5 is not particularly limited. For example, the conductor 5 may be composed of Cu, Al, Fe, Ag, Au, or an alloy containing these metals. The material of the insulating coating layer is not particularly limited. The material of the insulating coating layer may also be, for example, polyurethane, polyamide-imide, polyimide, polyester, polyester-imide, and / or polyester-nylon.

[0027] The cross-sectional shape of the conductor 5 is not particularly limited. As the cross-sectional shape, a circular shape and a flat shape are exemplified. In the embodiment of the present disclosure, the cross-sectional shape of the conductor 5 is a circular shape.

[0028] The core 6 has at least soft magnetic metal particles. There is no particular restriction on the material of the soft magnetic metal particles. The material of the soft magnetic metal particles may be, for example, ferrites such as Mn-Zn ferrite, Ni-Cu-Zn ferrite, soft magnetic alloys such as Fe-Si alloy, Fe-Si-Al alloy, Fe-Si-Cr alloy, and Permalloy (Fe-Ni alloy). There is no particular restriction on the microstructure of the soft magnetic metal particles. The microstructure of the soft magnetic metal particles may be amorphous or may contain crystals. In the case where the soft magnetic metal particles are amorphous, the soft magnetic metal particles may be flattened in advance using a crusher or the like. There is no particular restriction on the grain size when the soft magnetic metal particles contain crystals. The grain size may be, for example, less than 1 μm.

[0029] The soft magnetic metal particles may contain Fe-based soft magnetic particles, that is, soft magnetic particles containing Fe at a content ratio of 90 at % or more.

[0030] The average particle size of the soft magnetic metal particles in the core 6 is not particularly limited. The average equivalent circle diameter of the soft magnetic metal particles when observing the cross section of the core 6 with SEM can also be 1 μm or more and 100 μm or less. The equivalent circle diameter refers to the diameter of a circle with the same area. Hereinafter, the equivalent circle diameter of the particles in the cross section is sometimes referred to as the particle size.

[0031] The soft magnetic metal particles include specific particles with a particle size of 10 μm or more and 50 μm or less. The proportion of the specific particles contained in the soft magnetic metal particles in the core 6 is not particularly limited. The total area of ​​the specific particles in the cross section of the core 6 may be 50% or more relative to the total area of ​​the soft magnetic metal particles.

[0032] The core 6 may also contain a thermosetting resin (binder). The type of thermosetting resin is not particularly limited. Examples of thermosetting resins include epoxy resins, diallyl phthalate resins, phenolic resins, polyimides, polyamide-imides, silicone resins, and resins obtained by combining these. The core 6 may also contain epoxy resins as thermosetting resins.

[0033] The winding portion 4 has an inner peripheral surface 4β1 , an outer peripheral surface 4β4 , and a first end surface 4β2 and a second end surface 4β3 located on opposite sides to each other along the winding axis center 4α.

[0034] like Figure 1 As shown, the area within 100 μm from the inner circumference 4β1 toward the reel center 4α is set as the winding inner circumference vicinity area 6β1, the area within 100 μm from the first end face 4β2 toward the outer direction parallel to the reel center 4α is set as the first end face vicinity area 6β2, and the area within 100 μm from the second end face 4β3 toward the outer direction parallel to the reel center 4α is set as the second end face vicinity area 6β3. There is a winding portion 4 in the outer direction perpendicular to the reel center 4α, and the area within 280 μm from the reel center 4α toward the perpendicular outer direction is set as the core center area 6α. The area within 200 μm from the nearest surface in the core 6 is set as the outer wall area 6γ.

[0035] The density of the core 6 is not particularly limited. For example, it may be 5.00 g / cm 3 Above 7.00g / cm 3 the following.

[0036] The density of the core central region 6α may be greater than that of the outer wall region 6γ. Since the density of the core central region 6α is greater than that of the outer wall region 6γ, the DC superposition characteristics of the inductor 2 are easily improved.

[0037] like Figure 1 As shown, the portion where the inner peripheral surface 4β1 intersects with the first end surface 4β2 or the second end surface 4β3 is set as the coil corner 4β5. Figure 3 As shown, a portion of the coil corner 4β5 that is 20 μm or more and 50 μm or less is defined as a coil corner vicinity region 6β5. That is, t1 = 20 μm, t2 = 50 μm.

[0038] The average interparticle distance of the specific particles in the core central region 6α is defined as D1, and the average interparticle distance of the specific particles in the coil corner vicinity region 6β5 is defined as D2, and 0<D1 / D2<1.00. It may be 0.01≤D1 / D2≤0.99, 0.19≤D1 / D2≤0.70, or 0.19≤D1 / D2≤0.66.

[0039] When D1 / D2 is within the above range, an inductor 2 having high inductance and DC superposition characteristics can be obtained. When D1 / D2 is too high, the DC superposition characteristics are particularly likely to be degraded.

[0040] The average particle size of the specific particles in the core central region 6α is set to R1, and the average particle size of the specific particles in the coil corner vicinity region 6β5 is set to R2. It can be 0.20≤R1 / R2≤5.00, 0.50≤R1 / R2≤2.00, or 0.53≤R1 / R2≤1.84.

[0041] By setting R1 / R2 within the above range, even if the density difference between the core central region 6α and the outer wall region 6γ is small, for example, even if it is 0.20 g / cm 3 Next, the DC superposition characteristics of the inductor 2 are also easily improved.

[0042] Hereinafter, the measurement method of R1, R2, D1 and D2 will be described.

[0043] First, if Figure 1 As shown, the inductor 2 is cut through the center 4α of the winding axis to obtain a cross section parallel to the center 4α of the winding axis. Next, the core central region 6α and the region 6β5 near the corner of the coil are observed using an SEM to obtain an SEM image. There is no particular limitation on the magnification and size of the SEM image, as long as the magnification and size of the specific particles contained in each region can be appropriately observed. The magnification can also be, for example, 10 to 1000 times.

[0044] Next, the specific particles contained in each region are identified. The method for identifying the specific particles is not particularly limited. The specific particles can be identified visually or using image analysis software.

[0045] In the core central region 6α, particles having a particle size of 10 μm to 50 μm and including the entire core central region 6α are set as specific particles. In contrast, in the coil corner vicinity region 6β5, particles having a particle size of 10 μm to 50 μm and including at least a part of the coil corner vicinity region 6β5 are set as specific particles.

[0046] (D1, D2)

[0047] In each region, the interparticle distance between mutually adjacent specific particles is measured. First, between the surface and the surface of mutually different specific particles, a line segment is drawn in a manner with the shortest length. The length of this line segment becomes the interparticle distance between mutually adjacent specific particles.

[0048] The "specific particles adjacent to each other" refer to specific particles in which, when the line segment is drawn, the line segment does not overlap with other soft magnetic metal particles having a particle size of 10 μm or more.

[0049] In each region, all the specific particles adjacent to each other are identified, and the inter-particle distances between the specific particles adjacent to each other are measured. Then, the measured inter-particle distances are averaged to calculate D1 and D2.

[0050] The coil corner vicinity region 6β5 may be two corner vicinity regions 6β5 disposed opposite to each other with respect to the winding axis center 4α. In this case, both corner vicinity regions 6β5 may satisfy 0<D1 / D2<1.00. The DC superposition characteristics of the inductor 2 are easily improved.

[0051] The coil corner vicinity region 6β5 may be four corner vicinity regions 6β5. In this case, all of the four corner vicinity regions 6β5 may satisfy 0<D1 / D2<1.00. The DC superposition characteristics of the inductor 2 are easily improved.

[0052] In particular, the core 6 is made by hot pressing the soft magnetic metal powder and making Figure 1 , Figure 2 In the case of the inductor 2 having the shape shown, magnetic flux is likely to concentrate near the edge of the coil, that is, in a region 6β5 near the corner of the coil, and magnetic saturation is likely to occur.

[0053] Therefore, in order to improve both the inductance and DC superposition characteristics of the entire inductor 2, it is preferable to locally reduce the magnetic permeability of the coil corner vicinity region 6β5 so as to prevent magnetic saturation. Therefore, it is preferable that the interparticle distance of the soft magnetic metal particles is large.

[0054] In contrast, in the core portion including the core central region 6α, it is preferred to make the magnetic path as short as possible and to allow the magnetic flux to flow straightly. Therefore, in the core portion, it is preferred to increase the magnetic permeability locally. Therefore, it is preferred that the interparticle distance of the soft magnetic metal particles is small.

[0055] Therefore, since the coil corner vicinity region 6β5 satisfies 0<D1 / D2<1.00, the inductance and DC superposition characteristics of the inductor 2 are improved.

[0056] (R1, R2)

[0057] The particle sizes of all specific particles included in each region are measured, and then R1 and R2 are calculated by averaging the measured particle sizes.

[0058] Next, use Figure 4 and Figure 5 illustrate Figure 1 The manufacturing method of the inductor 2 is shown.

[0059] (Production method 1)

[0060] like Figure 4 As shown, the inductor 2 manufactured by the manufacturing method 1 of the inductor 2 in one embodiment of the present disclosure is manufactured by integrating two preforms 60a and 60b and an insertion member 40a having a winding portion 4 made of an air-core coil or the like.

[0061] (Preform)

[0062] As materials for the preforms 60a and 60b, soft magnetic metal powder containing soft magnetic metal particles and resin are prepared.

[0063] The shape of the soft magnetic metal particles contained in the soft magnetic metal powder is not particularly limited. The shape of the soft magnetic metal particles may be, for example, spherical, flat, or needle-shaped.

[0064] When making a preform, one soft magnetic metal powder can be used, or two or more soft magnetic metal powders with different shapes, average particle sizes, compositions, etc. can be mixed. When one soft magnetic metal powder is used, the average particle size of the soft magnetic metal powder is not particularly limited. For example, it can be 1 μm to 100 μm. As long as a large number of soft magnetic metal particles with a particle size of 10 μm to 50 μm and easy to become specific particles are contained.

[0065] When two or more soft magnetic metal powders are mixed and used, the average particle size of each soft magnetic metal powder is not particularly limited. For example, a soft magnetic metal powder whose average particle size is 10 μm to 50 μm and whose main particles are smaller than the specific particles may be mixed and used.

[0066] The resin is not particularly limited, and examples thereof include epoxy resins, phenolic resins, polyimide resins, polyamide-imide resins, and silicone resins. In addition, a resin obtained by appropriately combining these resins may be prepared.

[0067] Next, the soft magnetic metal powder and the resin are mixed and granulated to obtain particles. The granulation method is not particularly limited. For example, the resin can be added to the soft magnetic metal powder, stirred and dried. In addition, the average particle size and particle size distribution of the particles can also be appropriately adjusted.

[0068] The content ratio of the resin is not particularly limited, and may be, for example, 1.0 to 6.0 parts by weight relative to 100 parts by weight of the soft magnetic metal powder.

[0069] Before mixing the soft magnetic metal powder and the resin, an insulating film may be formed on the surface of the soft magnetic metal particles. For example, a SiO2 film, that is, an insulating film, may be formed by a sol-gel method.

[0070] Coarse particles can also be removed by adding a resin to the soft magnetic metal powder and stirring the mixture and then passing it through a mesh screen. In addition, the resin can also be diluted with a solvent when added to the soft magnetic metal powder. For example, ketones are used as solvents.

[0071] Next, the preforms 60a and 60b are prepared by compression molding. Specifically, the obtained particles are filled into a mold and pressed to obtain the preforms 60a and 60b. The preforms 60a and 60b prepared by compression molding are powder compacts containing soft magnetic metal particles and resin.

[0072] The pressure during pressurization is not particularly limited, and the higher the pressure, the more likely the soft magnetic metal particles are to be flattened. For example, the pressure may be 400 MPa to 1000 MPa.

[0073] In production method 1, if Figure 4 As shown, the preform 60a has a pot-type shape, and the preform 60b has a RT-type shape.

[0074] (Integration of preform and insert parts)

[0075] First, the preform 60a is inserted into the mold. Figure 4As shown, the insert member 40a is arranged at a predetermined position on the preform 60a. Next, the preform 60b is arranged at a predetermined position on the preform 60a and the insert member 40a. In addition, the core material may be appropriately filled into the mold before the preform 60b is inserted into the mold. The following description assumes that the core material is not filled. In addition, Figure 4-5 In Figure 1 , Figure 2 The diagram is shown in the figure with different numbers of windings, but the number of windings can be changed appropriately.

[0076] Next, hot pressing is performed. Specifically, after the preforms 60a and 60b inserted into the mold are heated to a temperature at which the resin softens, the preforms 60a and 60b and the insert component 40a are hot pressed together. The preforms 60a and 60b or the insert component 40a may also be heated (preheated) in advance. In addition, the frame or punch of the mold may also be heated. The direction of pressurization is the winding axis direction of the coil. By applying pressure, the winding portion 4 and the core portion 6 are hot pressed together to form an integrated whole. The preforms 60a and 60b are deformed by hot pressing. Figure 4 The gap shown is appropriately filled with the preforms 60a and 60b. The pressure during the thermocompression bonding is not particularly limited. For example, it is 100 MPa to 400 MPa. The temperature during the thermocompression bonding is not particularly limited. For example, it is 50°C to 100°C.

[0077] The preform 60a and the preform 60b are integrally formed by thermocompression bonding to obtain the core 6.

[0078] The inductor 2 removed from the mold after thermocompression bonding may be heated to further cure the resin. The heating temperature at this time is not particularly limited and may be set to 150°C to 200°C, for example.

[0079] (Method of controlling D1 / D2)

[0080] In the above method, the heat pressing Figure 4 The preforms and insert components 40a shown are obtained Figure 1 In the case of the inductor 2 shown, since Figure 1 The distance between the coil corner 4β5 at the intersection of the inner circumferential surface 4β1 and the second end surface 4β3 is within the specified range, and the coil corner vicinity area 6β5 is located near the portion where the preform 60a having a pot-shaped shape and the preform 60b having an RT-shaped shape are crimped.

[0081] The core 6 of the inductor 2 is generally made of soft magnetic metal powder. The higher the density, the higher the magnetic permeability. Therefore, it is preferable to make the core 6 as a whole have a high density. Therefore, it is considered that in order to improve the magnetic permeability, it is preferable to combine the preform 60a having a pot-shaped shape, the preform 60b having an RT-shaped shape, and the insert 40a without a gap when combining the preform 60a and the preform 60b.

[0082] In the manufacturing method 1 of the inductor 2 according to one embodiment of the present disclosure, a taper may be formed at the front end of the preform 60b having the RT shape, that is, at the portion located near the coil corner vicinity region 6β5 in the end. By forming the taper, a gap is generated at the portion located near the coil corner vicinity region 6β5 when the preform 60a, the preform 60b, and the insert member 40a are combined.

[0083] When preforms containing soft magnetic metal particles and resin are hot-pressed together, the resin seeps out at the joint. As described above, when a taper is formed at the front end of the preform 60b, a lot of resin seeps out from the preform 60a and the preform 60b into the gap created by the taper. In contrast, relatively few soft magnetic metal particles move from the preform 60a and the preform 60b to the gap. Therefore, in the gap created by the taper and its vicinity, the density of the soft magnetic metal particles decreases, and the average inter-particle distance of specific particles increases. That is, D2 increases in the area 6β5 near the two corners where the distance between the two coil corners 4β5 is within the specified range from the inner peripheral surface 4β1 to the second end surface 4β3.

[0084] On the other hand, the average inter-particle distance of the specific particles in the core central region 6α hardly changes due to the presence or absence of the above-mentioned taper. Therefore, D1 hardly changes due to the presence or absence of the above-mentioned taper.

[0085] Therefore, by forming the above-mentioned taper, D1 / D2 can be reduced to less than 1.00 in the two coil corner vicinity areas 6β5 where the inner circumferential surface 4β1 intersects with the second end surface 4β3. That is, 0<D1 / D2<1.00 can be satisfied in any of the two coil corner vicinity areas 6β5 disposed opposite to each other with respect to the winding axis center 4α.

[0086] In addition to forming the taper, D1 / D2 can be controlled by changing various conditions in particular during thermocompression bonding.

[0087] D1 / D2 can be adjusted by adjusting the temperature during hot pressing. By increasing the temperature during hot pressing, the resin becomes softer and the resin seeping into the above gap increases. As a result, D2 further increases and D1 / D2 is easily reduced. On the contrary, by lowering the temperature during hot pressing, the resin becomes harder and the resin seeping into the above gap decreases. On the other hand, the ease with which the soft magnetic metal particles can move into the above gap is difficult to change. As a result, even if a taper is formed, D2 is not easy to increase and D1 / D2 is not easy to decrease.

[0088] Even if the type of resin is a soft resin, D1 / D2 is easily reduced by forming a taper. On the contrary, by using a hard resin, D1 / D2 is not easily reduced even if a taper is formed.

[0089] D1 / D2 can also be controlled by controlling the particle size of the soft magnetic metal particles contained in the preform 60a having a can shape and / or the particle size of the soft magnetic metal particles contained in the preform 60b having an RT shape. D1 / D2 can be easily reduced by making the particle size of the specific particles contained in the preform 60b having an RT shape relatively small.

[0090] By making the particle size of the soft magnetic metal particles contained in the preform 60b having the RT type shape relatively small, the particle size of the soft magnetic metal particles contained in the core central region 6α becomes smaller, and D1 becomes smaller. In contrast, the soft magnetic metal particles move from both the preform 60a and the preform 60b to the gap generated by the formation of the taper. Therefore, even if the particle size of the soft magnetic metal particles contained in the preform 60b having the RT type shape is relatively reduced, D2 is difficult to become as small as D1. Therefore, by making the particle size of the specific particles contained in the preform 60b having the RT type shape relatively small, D1 / D2 is easily reduced.

[0091] (Production method 2)

[0092] Hereinafter, Production Method 2 will be described, but points not particularly described are the same as Production Method 1.

[0093] In production method 2, Figure 4 Specifically, first, the preform 60b is inserted into the mold. Next, the insert component 40a is arranged at a predetermined position on the preform 60b. Next, the preform 60a is arranged at a predetermined position on the preform 60b and on the insert component 40a.

[0094] In this case, unlike the production method 1, Figure 1The coil corner vicinity area 6β5, where the distance between the inner circumferential surface 4β1 and the first end surface 4β2, that is, the coil corner 4β5, is within a prescribed range, is located near the portion where the preform 60b having an RT shape and the preform 60a having a pot shape are crimped. By forming a taper on the preform 60b having an RT shape, D1 / D2 can be reduced to less than 1.00 in the two corner vicinity areas 6β5 where the distance between the inner circumferential surface 4β1 and the first end surface 4β2, that is, the two coil corners 4β5, is within a prescribed range. That is, 0<D1 / D2<1.00 can be satisfied in any of the two corner vicinity areas 6β5 arranged opposite to each other relative to the winding axis center 4α.

[0095] (Production method 3)

[0096] Hereinafter, Production Method 3 will be described, but the parts not particularly described are the same as those of Production Method 1.

[0097] like Figure 5 As shown, the inductor 2 manufactured by the manufacturing method 3 of the inductor 2 in one embodiment of the present disclosure is manufactured by integrating three preforms 60c to 60e and an insertion member 40a having a winding portion 4 formed of an air-core coil or the like.

[0098] (Preform)

[0099] The preforms 60c to 60e are the same as the preforms 60a and 60b except for the shapes.

[0100] In production method 3, if Figure 5 As shown, the preforms 60c and 60e have a pot-like shape, and the preform 60d has a cylindrical shape.

[0101] (Integration of preform and insert parts)

[0102] First, the preform 60c is inserted into the mold. Figure 5 As shown, the insert member 40a and the preform 60d are arranged at the predetermined position on the preform 60c. Next, the preform 60e is arranged at the predetermined position on the preforms 60c, 60d and the insert member 40a. In addition, the core material may be appropriately filled into the mold before the preform 60d is inserted into the mold, or before the preform 60e is inserted into the mold. In the following, it is assumed that the core material is not filled.

[0103] Next, hot pressing is performed. Specifically, after the preforms 60c~60e inserted into the mold are heated to a temperature at which the resin softens, the preforms 60c~60e and the insert components 40a are hot pressed together. The preforms 60c~60e or the insert components 40a may also be heated in advance (preheating). In addition, the frame or punch of the mold may also be heated. The direction of pressurization is the winding axis direction of the coil. The winding portion 4 and the core portion 6 are hot pressed together and integrated by applying pressure. The preforms 60c~60e are deformed by hot pressing, and the preforms 60c~60e are appropriately filled. Figure 5 within the gap shown.

[0104] The preforms 60 c to 60 e are integrally formed by thermocompression bonding to obtain the core 6 .

[0105] In the manufacturing method 3 of the inductor 2 according to one embodiment of the present disclosure, a taper may be formed at the front end of the preform 60d having a cylindrical shape, that is, the portion located near the coil corner vicinity region 6β5 in the end. A taper may be formed at the front end of the preform 60d having a cylindrical shape. By forming the taper, a gap is generated in the portion located near the coil corner vicinity region 6β5 when the preforms 60c to 60e and the insert member 40a are combined.

[0106] When preforms containing soft magnetic metal particles and resin are heat-pressed together, the resin seeps out at the joint. As described above, when the front end of the preform 60d is tapered, a lot of resin seeps out from the preforms 60c to 60e into the gaps created by the tapered shape. In contrast, relatively few soft magnetic metal particles move from the preforms 60c to 60e to the gaps. Therefore, in the gaps created by the tapered front ends on both sides of the preform 60d and in their vicinity, the density of the soft magnetic metal particles decreases, and the average inter-particle distance of specific particles increases. That is, D2 increases in the area 6β5 near the two corners where the distance between the two coil corners 4β5 at the intersection of the inner circumferential surface 4β1 and the first end surface 4β2 is within a prescribed range, and in the area 6β5 near the two corners where the distance between the two coil corners 4β5 at the intersection of the inner circumferential surface 4β1 and the second end surface 4β3 is within a prescribed range. That is, in Figure 1 In the illustrated vicinity of all four corners, regions 6β5, D2 rises.

[0107] On the other hand, the average inter-particle distance of the specific particles in the core central region 6α hardly changes due to the presence or absence of the above-mentioned taper. Therefore, D1 hardly changes due to the presence or absence of the above-mentioned taper.

[0108] Therefore, by forming the above-mentioned taper, D1 / D2 can be reduced to less than 1.00 in all four corner vicinity regions 6β5, and 0<D1 / D2<1.00 can be satisfied.

[0109] In manufacturing method 3, D1 / D2 can be reduced to less than 1.00 in all four corner vicinity regions 6β5 of inductor 2, and 0<D1 / D2<1.00 can be satisfied. That is, compared with inductor 2 manufactured by manufacturing methods 1 and 2, inductance and DC superposition characteristics can be easily improved.

[0110] (Other production methods)

[0111] The method for making the inductor 2 disclosed in the present invention is not limited to the above method. In particular, as for the shape and number of the cores, as long as the final Figure 1 The inductor 2 shown is not particularly limited. In addition, as shown in the present disclosure, a molded integral type coil component may be used, that is, a coil component in which the entire coil component except for the lead wire portion of the conductor wire is sealed with resin.

[0112] The coil component of the present disclosure is not limited to an inductor. For example, it may also be a coil component such as a transformer or a reactor. However, if it is considered that the coil component of the present disclosure is easy to increase the inductance, and the transformer and the reactor are difficult to be molded into an integral type, the coil component of the present disclosure may also be an inductor.

[0113] The power supply device of the present disclosure includes the above-mentioned coil component and may be, for example, a power supply device such as a switching power supply or a power amplifier.

[0114] [Example]

[0115] Hereinafter, the present disclosure will be described based on more detailed examples, but the present disclosure is not limited to these examples.

[0116] Experimental Example 1

[0117] The method for producing the inductor samples in the examples and comparative examples shown in Table 1 will be described.

[0118] First, prepare Figure 4 The preforms 60a and 60b are shaped as shown. Furthermore, an insert component 40a having a winding portion 4, lead wires and terminals is also prepared. Figure 4 Leads and terminals are omitted.

[0119] (Preform)

[0120] Soft magnetic metal powder containing soft magnetic metal particles and resin are prepared as materials for the preform 60a. The material of the soft magnetic metal particles is Fe-Si alloy (Fe 93.5 wt%, Si 6.5 wt%). The particle size of the soft magnetic metal powder is R2, which is the value shown in Table 1. Epoxy resin is used as the resin.

[0121] Next, an insulating film is formed on the surface of the soft magnetic metal particles. Specifically, a SiO2 film, that is, an insulating film, is formed by a sol-gel method. The thickness of the insulating film is about 40 nm.

[0122] Next, the soft magnetic metal powder and the resin are mixed and granulated to obtain particles. Specifically, the resin is added to the soft magnetic metal powder and stirred, and then dried at 40°C for 10 hours. The content of the soft magnetic metal powder is set to 100 parts by weight, and the content of the resin is 2 to 3 parts by weight. The type of resin is epoxy resin. After adding the resin to the soft magnetic metal powder and stirring, the powder is passed through a mesh to remove coarse particles. Specifically, the powder is passed through a mesh with a mesh size of 100 μm. The average particle size of the particles finally obtained is about 60 μm.

[0123] Next, the obtained pellets are filled into a mold for core forming, thereby obtaining a Figure 4 The preform 60a is a can-shaped preform shown in FIG. The forming pressure is 6 ton / cm 2 In addition, regarding the density D2 of the preform 60a, it is the value shown in Table 1.

[0124] Figure 4 The preform 60b having the RT type shape shown is produced under the same conditions as the preform 60a except for the shape and the particle size of the soft magnetic metal powder. As for the particle size of the soft magnetic metal powder in the preform 60b, R1, R2 and R1 / R2 are the values ​​shown in Table 1. As for the density of the preform 60b, D1, D2 and D1 / D2 are the values ​​shown in Table 1.

[0125] In each example, a taper was appropriately formed at the front end of the preform 60 b so that D1 / D2 had the values ​​shown in Table 1.

[0126] (Insert Part)

[0127] The dimensions of the winding portion 4 in the insert 40a are 4.67 mm in outer diameter, 2.80 mm in inner diameter, 0.22 mm in wire diameter (diameter of the conductor 5), 61.5 ts. in winding number, and 4.16 mm in height H. The conductor 5, lead wires, and terminals are made of Cu.

[0128] (Integration of preform and insert parts)

[0129] First, the preform 60a is inserted into the mold. Figure 4 As shown, the insert member 40a and the preform 60b are arranged at predetermined positions.

[0130] Next, hot pressing is performed. Specifically, the preforms 60a, 60b and the insert component 40a inserted into the mold are heated at 80°C to soften the resin and then pressurized. The pressurization direction is the winding axis direction of the coil. By pressurizing, the coil and each preform are hot pressed and integrated. The forming pressure during hot pressing is 100 MPa.

[0131] After forming by thermocompression bonding, the inductor 2 removed from the mold is heated to cure the resin. The heating temperature is set to 150° C. to 200° C., and the heating time is set to 1 hour to 3 hours. The heating temperature and heating time are appropriately controlled so that D1 / D2 becomes the value shown in Table 1.

[0132] Through the above process, we can obtain Figure 1 The inductor 2 shown has a core 6 with dimensions of 5.50 mm×5.50 mm×5.15 mm and a height of 5.15 mm.

[0133] R1, R2, D1 and D2 of each sample are calculated based on the SEM image of the cut surface obtained by cutting the inductor of each sample with a cross section including the center of the winding axis. The results are shown in Table 1. The magnification of the SEM image is 500 times. R2 and D2 are respectively measured in the two corner vicinity areas 6β5 where the distance between the two coil corners 4β5, which is the part where the inner circumferential surface 4β1 and the second end surface 4β3 intersect, is within a specified range. It is confirmed that R2 and D2 are consistent with each other in the two corner vicinity areas 6β5. In the calculation of R1 and R2, soft magnetic metal particles with a particle size less than 10μm or greater than 50μm are not considered. In the calculation of D1 and D2, soft magnetic metal particles with a particle size less than 10μm are not considered.

[0134] The inductance L0 before applying a direct current was measured for each sample at a measurement frequency of 1.0 MHz and a measurement voltage of 500 mV using an RF impedance material analyzer (4491A manufactured by Agilent Technologies, Inc.). The results are shown in Table 1.

[0135] For each sample, Isat was measured to evaluate the DC superposition characteristics. Specifically, for each inductor, a DC current was applied from 0, and the magnitude of the DC current when the inductance was reduced to 0.8×L0 relative to the inductance L0 when the DC current was 0 was defined as Isat. The results are shown in Table 1.

[0136] L0×Isat was calculated for each sample. The results are shown in Table 1. When L0×Isat was 6.0 (H×A) or more, the inductance and DC superposition characteristics were good. The results are shown in Table 1.

[0137] In all samples, the density of the core central region 6α was greater than that of the outer wall region 6γ using an X-ray density distribution measuring device, and the density difference between the core central region 6α and the outer wall region 6γ was 0.20 g / cm 3 the following.

[0138]

Table 1

[0139]

[0140] As can be seen from Table 1, the coil component with 0<D1 / D2<1.00 has higher L0×Isat and better inductance and DC superposition characteristics than the coil component with D1 / D2≥1.00.

[0141] [Note]

[0142] The technology based on the present disclosure includes the following configuration examples, but is not limited thereto.

[0143] A coil component of a structural example of the present disclosure comprises a core portion including soft magnetic metal particles and a resin, and a winding portion formed by winding a conductor, wherein the winding portion is formed inside the core portion,

[0144] The winding portion has an inner peripheral surface, an outer peripheral surface, and an end surface.

[0145] The core portion has a central core area and an area near the coil corner, the central core area is located within a specified range from the center of the winding axis toward the vertical outer side, and the distance between the area near the coil corner and the coil corner where the inner peripheral surface and the end surface intersect is within a specified range.

[0146] The soft magnetic metal particles contain specific particles with a particle size of 10 μm or more and 50 μm or less. The average inter-particle distance of the specific particles in the central area of ​​the core is set to D1, and the average inter-particle distance of the specific particles in the area near the coil corner is set to D2, 0<D1 / D2<1.00.

[0147] In the coil component, an average particle size of the specific particles in the central region of the core may be R1, an average particle size of the specific particles in the region near the coil corners may be R2, and 0.20≤R1 / R2≤5.00.

[0148] In any of the coil components described above, the core may include an outer wall region, and a distance of the outer wall region from a surface of the core toward an inner side may be within a predetermined range.

[0149] The density of the central region of the core may also be greater than the density of the outer wall region.

[0150] In any of the above coil components, the density difference between the core central region and the outer wall region may be 0.20 g / cm 3 the following.

[0151] In any of the above coil components, the soft magnetic metal particles may include Fe-based soft magnetic particles.

[0152] In any of the above coil components, the resin may include epoxy resin.

[0153] In any of the above coil components, the coil corner vicinity regions may be two corner vicinity regions arranged opposite to each other relative to the winding axis center, and either corner vicinity region may satisfy 0<D1 / D2<1.00.

[0154] In any of the above coil components, the coil corner vicinity region may include four corner vicinity regions, and any of the corner vicinity regions may satisfy 0<D1 / D2<1.00.

[0155] In any of the above coil components, 0.19≤D1 / D2≤0.70.

[0156] A power supply device according to a structural example of the present disclosure includes any of the above-mentioned coil components.

[0157] Description of Reference Numerals

[0158] 2…Inductor

[0159] 4…Winding section

[0160] 4α…Scroll Center

[0161] 4β1…Inner Surface

[0162] 4β2…First end face

[0163] 4β3…Second end face

[0164] 4β4…peripheral surface

[0165] 4β5…Coil corner

[0166] 5…Conductor

[0167] 6…Core

[0168] 6α…SMIC Central Area

[0169] 6β1…Area near the inner circumference of the winding

[0170] 6β2…Area near the first end face

[0171] 6β3…Area near the second end face

[0172] 6β5…(coil) corner vicinity

[0173] 6γ…Outer wall area

[0174] 40a…Insert component

[0175] 60a~60e...preformed bodies.

Claims

1. A coil component, wherein: The coil component comprises a core portion including soft magnetic metal particles and a resin, and a winding portion formed by winding a conductor, wherein the winding portion is formed inside the core portion. The winding portion has an inner peripheral surface, an outer peripheral surface, and an end surface. The core portion has a central core area and an area near the coil corner, the central core area is located within a specified range from the center of the winding axis toward the vertical outer side, and the distance between the area near the coil corner and the coil corner where the inner peripheral surface and the end surface intersect is within a specified range, The soft magnetic metal particles contain specific particles with a particle size of not less than 10 μm and not more than 50 μm, the average inter-particle distance of the specific particles in the central area of ​​the core is set to D1, and the average inter-particle distance of the specific particles in the area near the coil corner is set to D2, 0<D1 / D2<1.

00.

2. The coil component according to claim 1, wherein The average particle size of the specific particles in the central region of the core is defined as R1, and the average particle size of the specific particles in the region near the coil corner is defined as R2, and 0.20≤R1 / R2≤5.

00.

3. The coil component according to claim 1 or 2, wherein: The core has an outer wall region, and a distance of the outer wall region from the surface of the core toward the inside is within a predetermined range. The density of the central region of the core is greater than the density of the outer wall region.

4. The coil component according to claim 3, wherein: The density difference between the central area of ​​the core and the outer wall area is 0.20 g / cm 3 the following.

5. The coil component according to claim 1 or 2, wherein: The soft magnetic metal particles contain Fe-based soft magnetic particles.

6. The coil component according to claim 1 or 2, wherein: The resin contains epoxy resin.

7. The coil component according to claim 1 or 2, wherein: The coil corner vicinity regions are two corner vicinity regions disposed opposite to each other with respect to the winding axis center, and any of the corner vicinity regions satisfies 0<D1 / D2<1.

00.

8. The coil component according to claim 1 or 2, wherein: The coil corner vicinity region includes four corner vicinity regions, and any of the corner vicinity regions satisfies 0<D1 / D2<1.

00.

9. The coil component according to claim 1 or 2, wherein: 0.19≤D1 / D2≤0.

70. 10 . A power supply device comprising the coil component according to claim 1 .

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