Magnetic component and electric / electronic apparatus

Abstract

A magnetic component according to one aspect of the present invention comprises: a pair of core bodies each having a middle leg part, side leg parts arranged on both sides of the middle leg part, and connection parts for connecting the middle leg part and the side leg parts; a winding part core arranged with a second gap L2 provided between opposing planes of the middle leg part; and a coil arranged around the winding part core and around which a conductor wire is wound. The winding part core is formed of a material different from that of the core bodies, and is disposed with a first gap L1 provided between the winding part core and the coil. The iron loss of the material of the winding part core is less than or equal to three times the iron loss of the material of the core bodies under a drive condition of a frequency of 100 kHz or greater. Thus, it is possible to increase productivity even with a complex core shape, and to make the apparatus smaller due to high-frequency compatibility.

Description

Magnetic parts and electrical and electronic equipment

[0001] The present invention relates to magnetic components and electric and electronic devices.

[0002] Patent Document 1 discloses a transformer that minimizes the effect of leakage flux on the coil, is optimal for various production types, and allows for easy setting of gap dimensions. This transformer has an intermediate core that has multiple abutment surfaces on the magnetic legs around which the coil of the closed magnetic circuit core is wound, and each of the portions that form these multiple abutment surfaces is curved.

[0003] Patent Document 2 discloses a hybrid core that can reduce reactor loss by reducing the effect of loss (copper loss) caused by eddy currents generated in a coil due to leakage magnetic flux. This hybrid core includes a core body having a center leg, side legs arranged on both sides of the center leg, and a connecting portion connecting the center leg and the side legs, the core body being made of an oxide-based magnetic material, and the center leg having a magnetic permeability adjusting portion, the magnetic permeability adjusting portion having a portion made of a compact of a mixed powder containing an Fe-based amorphous magnetic alloy powder and a binder component.

[0004] Japanese Utility Model Application Publication No. 03-92016

[0005] Ferrite cores, which are used as the iron core material in magnetic components, are made of oxide magnetic materials, which means that their resistivity is much higher than that of metallic magnetic materials, making them suitable for higher frequencies. However, the relative permeability of ferrite cores is generally around 1000 to 3000. In particular, transformers and inductors, which require an effective relative permeability of around 60 to 150, require the creation of an air gap that creates magnetic resistance in the magnetic path of the iron core. The creation of this air gap allows magnetic flux to leak through the air gap, which then interlinks with nearby windings, generating eddy currents in the conductor and causing increased loss. Because eddy currents are proportional to the square of the frequency, increased loss is a particular problem in high-frequency applications.

[0006] On the other hand, soft magnetic metal powder cores, which have a low relative magnetic permeability of the iron core, do not require the provision of an air gap as described above and are not affected by leakage magnetic flux. However, increasing the magnetic permeability is difficult in production, and the limiting magnetic permeability tends to decrease as the shape becomes more complex. Generally, for EE and EQ shapes, the limiting magnetic permeability is about 75. Furthermore, in the molding process for producing powder cores, the compressive force when placing the magnetic powder in a mold and compacting it is 10 ton / cm. 2 (approximately 1 GPa), and as the shape of the iron core becomes more complex, as mentioned above, there are many issues to be overcome in terms of productivity, such as damage to the mold and slow molding cycle times.

[0007] An object of the present invention is to provide magnetic components and electric / electronic devices that can be made more productive even when the core has a complex shape, and that can be made smaller by being compatible with high frequencies.

[0008] A magnetic component according to one embodiment of the present invention is a magnetic component comprising a pair of core bodies each having a center leg, side legs arranged on either side of the center leg, and a connecting portion connecting the center leg and the side legs, a winding core arranged between opposing flat surfaces of the center leg with a second gap L2, and a coil arranged around the winding core and wound with a conductive wire, wherein the winding core is formed of a material different from the core body and is arranged with a first gap L1 between it and the coil, and the material of the winding core has an iron loss that is three times or less that of the material of the core body under driving conditions with a frequency of 100 kHz or higher.

[0009] With this configuration, productivity is increased by using a material for the core body that can accommodate complex shapes, and by using a material for the winding core that has an iron loss that is three times or less that of the material for the core body under driving conditions where the driving frequency is 100 kHz or higher, loss is reduced at high frequencies (100 kHz or higher) and high circuit efficiency is achieved.

[0010] In the magnetic component, the magnetic material of the core body may be ferrite, and the magnetic material of the winding core may be soft magnetic metal. Soft magnetic metal materials require high-pressure molding, which makes it difficult to mass-produce complex shapes. However, by using ferrite for the core body, which has complexity, and soft magnetic metal for the winding core, which only requires a simple shape, a highly efficient core that can be mass-produced can be provided.

[0011] In the above magnetic component, when the first gap is L1 and the gap between the center leg portion and the winding core is L2, 1.6≦L1 2 It is preferable that L1 / L2≦20. 2 If / L2 is 1.6 or more, the copper loss generated in the coil settles to a stable low state, but if it exceeds 20, the loss stops decreasing and only the volume of the component increases, so an optimal design can be obtained within this range.

[0012] In the magnetic component, the winding core may be divided into two or more pieces, which reduces molding errors compared to molding the winding core as a single piece, improves the flatness and gap setting accuracy between the center leg and the winding core, and stabilizes characteristics.

[0013] In the magnetic component, the drive frequency may be 1 MHz or higher. That is, a drive frequency of 500 kHz contributes to product miniaturization compared to a drive frequency of 100 kHz, and a drive frequency of 1 MHz to 4 MHz makes it easier to miniaturize the product.

[0014] In the magnetic component, when the magnetic material of the winding core is made of a soft magnetic metal material, the metallic portion of this soft magnetic metal material may be made of an amorphous phase.

[0015] In the magnetic component, when the magnetic material of the winding core is made of a soft magnetic metal material, the metallic portion of this soft magnetic metal material may be made of an amorphous phase and a crystalline phase.

[0016] Another aspect of the present invention is an electric / electronic device incorporating the magnetic component described above. With this configuration, the use of a magnetic component that can achieve low loss, particularly in a high frequency range of drive frequencies of 100 kHz or higher, facilitates miniaturization of the electric / electronic device.

[0017] According to the present invention, it is possible to provide magnetic components and electric / electronic devices that can be made more compact by being compatible with high frequencies, while also being able to increase productivity even when the core has a complex shape.

[0018] 3A ; FIG. 3B is an external perspective view illustrating the magnetic component according to the present embodiment; FIG. 3C is an exploded perspective view illustrating the configuration of a core used in the magnetic component according to the present embodiment; FIG. 3D is a bottom view illustrating the magnetic component according to the present embodiment; FIG. 3E is a partially enlarged view of portion A in FIG. 3A ; FIG. 3F is a plan view showing the core shape of comparative component 2A; FIG. 3G is a plan view showing the core shapes of comparative components 2B to 2D; FIG. 3G is a graph showing the relationship between drive frequency and total loss; FIG. 3H is a graph showing the relationship between drive frequency and total loss; FIG. 3I is a graph showing the breakdown of losses at a drive frequency of 4000 kHz; FIG. 3I is a graph showing the breakdown of losses at a drive frequency of 1000 kHz; FIG. 3I is a graph showing the breakdown of losses at a drive frequency of 500 kHz; FIG. 3I is a graph showing the breakdown of losses at a drive frequency of 100 kHz; FIG. 3I is a graph showing the breakdown of losses at a drive frequency of 50 kHz; FIG. 3I is a graph showing the relationship between λ and copper loss; FIG. 3I is a graph showing the relationship between λ and Δp / ΔV; FIG. 3I is a graph showing the relationship between λ and copper loss (in the case of a solid wire); FIG. 3I is a graph showing the relationship between λ and Δp / ΔV (in the case of a solid wire); FIG. 3I is a graph showing the relationship between λ and copper loss; FIG. 3I is a graph showing the relationship between λ and Δp / ΔV. 1 is a diagram showing the relationship between λ and copper loss, a diagram showing the relationship between λ and Δp / ΔV, a diagram showing the relationship between a magnetic field and relative permeability, and a diagram showing the relationship between a magnetic field and relative permeability.

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same components will be designated by the same reference numerals, and the description of components that have already been described will be omitted as appropriate.

[0020] (Magnetic Component) Fig. 1 is an external perspective view illustrating a magnetic component according to this embodiment. Fig. 2 is an exploded perspective view illustrating the configuration of a core used in the magnetic component according to this embodiment. The magnetic component 1 according to this embodiment includes a pair of core bodies 10, a winding core 20, and a coil 30. Each of the pair of core bodies 10 has a center leg 11, side leg portions 12 arranged on both sides of the center leg 11, and a connecting portion 13 connecting the center leg 11 and the side leg 12. Each of the pair of core bodies 10 has a substantially E-shape, and the tips of the side leg portions 12 are butted against each other.

[0021] The winding core 20 is disposed between the opposing surfaces 11a of the center leg portions 11 of a pair of butted core bodies 10. The winding core 20 has an end face shape substantially identical to that of the center leg portions 11, and is provided as a simple cylindrical shape that extends uniformly with this end face shape. The winding core 20 may be divided into two or more pieces. In the example shown in FIG. 1, the winding core 20 is divided into two pieces that are butted together to form a single winding core 20.

[0022] The coil 30 is made of copper and is wound with a conductor wire. The conductor wire is wound around a bobbin (not shown). The conductor wire may be a Litz wire or a solid wire. The coil 30 is disposed around the winding core 20 and covers almost the entire winding core 20.

[0023] In the magnetic component 1 according to this embodiment having such a configuration, the iron loss of the material of the winding core 20 is three times or less the iron loss of the material of the core body 10 under driving conditions with a frequency of 100 kHz or more.

[0024] As an example, the magnetic material of the core body 10 is ferrite, and the magnetic material of the winding core 20 is a soft magnetic metal material. Because ferrite is a material that can be formed into complex shapes, using ferrite as the material for the core body 10, which has a complex shape such as an approximately E-shape, can increase core productivity. Furthermore, by using a material for the winding core 20 that has an iron loss three times or less of the material for the core body 10 under driving conditions of a frequency of 100 kHz or higher, even difficult-to-shape materials can be used for the winding core 20, as long as it has a simple shape, and furthermore, loss can be suppressed and circuit efficiency can be improved at high frequencies (100 kHz or higher).

[0025] When the winding core 20 is made of a soft magnetic metal material, the metallic portion of the soft magnetic metal material may be made of an amorphous phase, or may be made of an amorphous phase and a crystalline phase.

[0026] Here, since the winding core 20 contains an Fe-based amorphous magnetic alloy powder, it is possible to reduce loss (core loss) that occurs in the core (hybrid core) formed by the core body 10 and the winding core 20, compared to when the magnetic powder contained in the powder compact is made of crystalline alloy powder. From the viewpoint of reducing this core loss, the Fe-based amorphous magnetic alloy powder preferably contains an Fe-B-(P)-C system amorphous magnetic alloy powder, and more preferably consists of an Fe-B-(P)-C system amorphous magnetic alloy powder.

[0027] A specific example of an alloy (Fe-B-(P)-C amorphous alloy) that provides an Fe-B-(P)-C amorphous magnetic alloy powder is an Fe-based amorphous alloy whose composition is represented by the formula Fe100at%-a-b-c-x-y-z-tNiaCrbPxCyBzSit, where 0at%≦a≦10at%, 0at%≦b≦6at%, 0at%≦x≦15at%, 1at%≦y≦18at%, 1at%≦z≦19at%, and 0at%≦t≦10at%. In the above composition formula, Ni, Cr, P, and Si are optional additional elements.

[0028] The preferred ranges of the amounts of each element added to the Fe-B-(P)-C amorphous alloy are as follows: The amount a of Ni added is preferably 0 at% or more and 6 at% or less, and more preferably 0 at% or more and 4 at% or less. The amount b of Cr added is preferably 0 at% or more and 4 at% or less, and more preferably 1 at% or more and 2 at% or less. The amount x of P added may be preferably 0 at% or more and 15 at% or less. The amount y of C added is preferably 2 at% or more and 13 at% or less. From the viewpoint of reducing core loss, it is preferable to add B and Si, and the amount z of B added is preferably 1 at% or more and 15 at% or less, and the amount t of Si added is preferably 0.5 at% or more and 10 at% or less.

[0029] An Fe-B-(P)-C based amorphous alloy powder having the above composition can be obtained by using an alloy composition obtained by adding each element in these amounts to an iron (Fe) source and carrying out a conventional powder production method such as atomization.

[0030] The Fe-based amorphous magnetic alloy powder may be entirely amorphous or partially crystalline. Such a powder material having a crystalline portion and an amorphous portion may be a mixture of a powder of a crystalline magnetic material and a powder of an amorphous magnetic material, or may be a material having an amorphous phase and a crystalline phase in the powder. An example of the latter material is an Fe-based alloy containing elements that promote crystal precipitation, such as Nb, Cu, Si, and B, in which crystalline α-Fe (crystalline phase) is dispersed and precipitated in an amorphous parent phase (amorphous phase). Such a crystalline phase is formed by fine crystal grains of several to several tens of nanometers.

[0031] The particle size of the Fe-based amorphous magnetic alloy powder is not limited. When the particle size is defined by the average particle size D50 (the particle size at which the cumulative volume of the particle size volume distribution of the Fe-based amorphous magnetic alloy powder measured by laser diffraction scattering is 50%), it is usually in the range of 1 μm to 30 μm. From the viewpoint of improving the handling property and increasing the packing density of the Fe-based amorphous magnetic alloy powder in the powder compact, the average particle size D50 of the Fe-based amorphous magnetic alloy powder is preferably 2 μm to 15 μm, more preferably 3 μm to 13 μm.

[0032] The content of the Fe-based amorphous magnetic alloy powder in the powder compact is not limited and can be appropriately set depending on the application, taking into consideration the composition of the resin material, the manufacturing process, and the like.

[0033] The powder compact is formed from a mixed powder containing the Fe-based amorphous magnetic alloy powder and a binder component. In a preferred embodiment, the mixed powder further contains an oxide-based inorganic material. In some cases, this oxide-based inorganic material is preferably phosphate glass from the viewpoint of improving heat resistance.

[0034] The binder component is used to bind materials contained in the powder compact, such as Fe-based amorphous magnetic alloy powder, and a specific example is a resin-based material. In this specification, the resin-based material refers to a material containing a resin and / or a component based on a resin (a component in which at least a portion of a resin has undergone a compositional change, and a specific example is a (partial) pyrolysis product of a resin).

[0035] Examples of resins contained in the resin-based material include acrylic resin, silicone resin, phenolic resin, polyimide, polyamide, and polyester.

[0036] The method for forming a powder compact from the mixed powder is not limited. However, from the viewpoint of increasing the packing density of the Fe-based amorphous magnetic alloy powder in the powder compact, it is preferable to pressure-mold the mixed powder as is or granulated powder formed from the mixed powder. The pressure range is, for example, 0.5 GPa to 2.5 GPa. Since the Fe-based amorphous magnetic alloy powder contained in the molded product obtained by pressure molding may contain residual processing strain, it is preferable to heat the molded product to a temperature range of 300°C to 550°C to relieve the processing strain. The atmosphere during heating for this strain relief may be a non-oxidizing atmosphere, an oxidizing atmosphere, or a switched atmosphere. During this heating, the resin contained in the molded product may become a pyrolyzed product.

[0037] FIG. 3A is a plan view illustrating a magnetic component according to this embodiment. FIG. 3B is a bottom view illustrating a magnetic component according to this embodiment. FIG. 3B shows a bottom view of one core body 10 as viewed from the connecting portion 13 side. FIG. 4 is a partially enlarged view of portion A in FIG. 3A. In the magnetic component 1 according to this embodiment, a gap is provided between the winding section core 20 and the coil 30. This gap is referred to as a first gap L1 (hereinafter, also simply referred to as "L1"). In addition, in the magnetic component 1, a gap is provided between the center leg portion 11 and the winding section core 20. This gap is referred to as a second gap L2 (hereinafter, also simply referred to as "L2"). In addition, the length of the center leg portion 11 extending toward the winding section core 20 is referred to as the length D of the center leg portion (hereinafter, also simply referred to as "D").

[0038] In this case, in the magnetic component 1 according to this embodiment, 1.6≦L1 2 / L2≦20. 2 If / L2 is 1.6 or more, the copper loss generated in the coil 30 is stable and low. 2 If / L2 exceeds 20, the loss stops decreasing and only the volume of the components increases, so within this range, an optimal design can be obtained that strikes a balance between suppressing loss and miniaturization.

[0039] (Example and Comparative Examples) Next, the results of studies conducted by the present inventors will be described. Here, the results of the studies are shown for magnetic component 1A, which is an example of magnetic component 1 according to the present embodiment, and magnetic components according to comparative examples (referred to as comparative components 2A to 2D).

[0040] The specifications of the magnetic component 1A are as follows: Magnetic path length of the core: 39.3 mm Cross-sectional area of ​​the core: 20.0 mm 2 Material of the core body 10...ferrite Material of the winding core 20...Fe-based amorphous magnetic alloy powder L2...0.1 mm D...1.5 mm Coil wire diameter...φ0.1 / 45P (litz wire) or φ0.95 (solid wire) Number of coil turns...20Ts Effective relative permeability...approximately 60 to 90

[0041] 5A is a plan view showing the core shape of the comparative component 2A. As shown in FIG. 5A, in the comparative component 2A, each of the pair of cores 102A has a substantially E-shaped configuration. The specifications of the comparative component 2A are as follows. Note that the specifications other than those described below are the same as those of the magnetic component 1A. - Material of the entire core 102A, including the center leg 112A...ferrite - Effective relative permeability...approximately 80 (the effective relative permeability is adjusted by providing a gap in the center leg 112A of the core 102A.)

[0042] FIG. 5B is a plan view showing the core shapes of the comparative parts 2B to 2D. As shown in FIG. 5B, in the comparative parts 2B to 2D, each of the pair of cores 102B has a substantially E-shaped shape. The pair of cores 102B are butted together without a gap. The specifications of the comparative parts 2B to 2D are as follows. Note that the specifications other than those listed below are the same as those of the magnetic part 1A. Number of coil turns: 22Ts Effective relative permeability: approximately 60 to 90 The material of the entire core 102B, including the center leg portion 112B, differs between the comparative parts 2B to 2D. The material of the core 102B of the comparative part 2B is Fe-based amorphous magnetic alloy powder. The material of the core 102B of the comparative part 2C is a virtual material for simulation in which the iron loss of the Fe-based amorphous magnetic alloy powder, which is the material of the core 102B of the comparative part 2B, is tripled. The material of the core 102B of the comparative part 2D is a ternary alloy (Fe—Si—Al alloy).

[0043] <Driving Frequency and Total Loss> Figures 6 and 7 are diagrams showing the relationship between driving frequency and total loss. Figure 6 shows the total loss for driving frequencies of 50 kHz to 1,000 kHz (1 MHz) for magnetic component 1A and comparative components 2A and 2B, respectively, and Figure 7 shows the total loss for driving frequencies of 50 kHz to 10,000 kHz (10 MHz) for magnetic component 1A and comparative components 2A and 2B, respectively. Note that Figures 6 and 7 show the cases where litz wire is used as the electric wire for coil 30 in magnetic component 1A and comparative components 2A and 2B.

[0044] As shown in Figure 6, magnetic component 1A exhibits lower total loss than comparative components 2A and 2B at drive frequencies of 100 kHz or higher. This tendency remains unchanged even at frequencies above 1000 kHz, as shown in Figure 7. Therefore, magnetic component 1A may have a drive frequency of 1 MHz or higher. In other words, compared to a drive frequency of 100 kHz, a drive frequency of 500 kHz contributes to product miniaturization, and a drive frequency of 1 MHz to 4 MHz makes it easier to miniaturize the product.

[0045] Figures 8 to 12 are diagrams showing the breakdown of losses. Figure 8 shows the breakdown of losses in magnetic component 1A and comparative components 2A to 2D at a drive frequency of 4000 kHz, Figure 9 shows the breakdown of losses in the same components at a drive frequency of 1000 kHz, Figure 10 shows the breakdown of losses in the same components at a drive frequency of 500 kHz, Figure 11 shows the breakdown of losses in the same components at a drive frequency of 100 kHz, and Figure 12 shows the breakdown of losses in the same components at a drive frequency of 50 kHz.

[0046] As shown in Figures 8 to 12, the lower the drive frequency, the higher the relative proportion of the DC resistance component of copper loss. For example, when the drive frequency shown in Figure 12 drops to 50 kHz, the DC resistance component becomes dominant over the AC loss component of copper loss due to leakage magnetic flux from the second gap L2. As a result, the comparative component 2A (ferrite core), which has the lowest iron loss, has the lowest loss overall.

[0047] 11, when the drive frequency is 100 kHz, the AC loss component of copper loss due to leakage magnetic flux from the gap in center leg 112A is higher in comparative component 2A compared to when the drive frequency is 50 kHz, resulting in no difference in loss between comparative component 2A (ferrite core) and magnetic component 1A. Furthermore, in comparative component 2B, because there is no gap in center leg 112B, the AC loss component of copper loss remains the same, but the influence of iron loss is greater, resulting in greater overall loss than in magnetic component 1A.

[0048] As shown in FIG. 10, when the drive frequency is 500 kHz, the influence of the AC loss component of the copper loss in the comparative component 2A (ferrite core) becomes even greater compared to when the drive frequency is 100 kHz or 50 kHz, whereas the AC loss component of the copper loss in the magnetic component 1A is not dominant and has the lowest loss.

[0049] 9 and 8, when the drive frequency is 1000 kHz or higher, the comparative component 2A (ferrite core) has the lowest iron loss compared to magnetic component 1A and the other comparative components 2B, 2C, and 2D, but the AC loss component of the copper loss is high due to the gap in center leg 112A. Furthermore, the comparative component 2B has the lowest AC loss component of the copper loss compared to magnetic component 1A and the other comparative components 2B, 2C, and 2D because there is no gap in center leg 112B, but the iron loss is high. The magnetic component 1A has a higher AC loss component of the copper loss than the comparative component 2B due to the presence of second gap L2, but the iron loss is low, showing the best loss results.

[0050] These verification results show that under driving conditions with a frequency of 100 kHz or higher, the material of the winding core 20 used in the magnetic component 1A should preferably be a material with an iron loss three times or less that of the material of the core body 10.

[0051] <λ and copper loss> Fig. 13 is a diagram showing the relationship between λ and copper loss. Fig. 13 shows the copper loss in the magnetic component 1A at λ = 0.025 to 62.5, with the drive frequency as a parameter. Here, λ = L1 2 / L2 (same below). In Fig. 13, L2 is fixed at 0.10 mm and L1 is changed. As shown in Fig. 13, copper loss decreases linearly up to λ = 1.6, and thereafter the rate of decrease tends to slow down. After λ = 20, copper loss shows a gradual increase.

[0052] <λ and Δp / ΔV> Fig. 14 is a diagram showing the relationship between λ and Δp / ΔV. Fig. 14 shows Δp / ΔV for magnetic component 1A at λ = 1.0 to 62.5, with drive frequency as a parameter. Here, ΔV is the increase in volume of core body 10 due to an increase in first gap L1, and Δp is the reduction in copper loss (the same applies below).

[0053] In the magnetic component 1A, the provision of the second gap L2 increases the magnetic resistance and suppresses the reduction in saturation magnetic flux density caused by the ferrite, and the first gap L1 reduces the effect of leakage magnetic flux generated by the second gap L2 on the coil 30. Increasing the first gap L1 reduces copper loss. On the other hand, increasing the first gap L1 increases the volume of the core body 10, i.e., increases the overall size of the magnetic component 1A.

[0054] 14, as λ increases with an increase in the first gap L1, the ratio of the copper loss reduction Δp to the increase in the volume of the core body 10 decreases, and this ratio remains approximately constant when λ is 20 or more. In other words, it can be seen that when λ exceeds 20, the increase in the volume of the core body 10 becomes a greater factor than the copper loss reduction effect. For this reason, it can be said that in the magnetic component 1A, it is preferable that 1.6≦λ≦20.

[0055] Next, we will show the results of a test using a solid wire instead of a Litz wire as the conductor of the coil 30. The solid wire used had a diameter of 0.95 mm, which corresponds to the cross-sectional area of ​​the Litz wire (φ0.1 / 45P) in the above specifications of the magnetic component 1A.

[0056] <λ and Copper Loss> Figure 15 shows the relationship between λ and copper loss (for a single wire). Figure 15 shows the copper loss of the magnetic component 1A at λ = 0.025 to 62.5 mm, with the drive frequency as a parameter. In Figure 15, L2 is fixed at 0.10 mm, while L1 is varied. As shown in Figure 15, when a single wire is used as the conductor of the coil 30, copper loss increases compared to when a litz wire is used, but the relationship between drive frequency and copper loss shows a similar trend to that of a litz wire. That is, when a single wire is used, copper loss decreases linearly up to λ = 1.6, and the rate of decrease thereafter tends to slow. After λ = 20 mm, copper loss shows a gradual increase.

[0057] <λ and Δp / ΔV> Figure 16 shows the relationship between λ and Δp / ΔV (for a single wire). This figure shows Δp / ΔV for the magnetic component 1A at λ = 1.0 to 62.5, with the drive frequency as a parameter. As shown in Figure 16, when a single wire is used as the conductor of the coil 30, the ratio of the copper loss reduction Δp to the volume increase of the core body 10 decreases as λ increases with the first gap L1. The ratio then increases between λ = 1.6 and λ = 3.969 at drive frequencies of 750 kHz and above, and between λ = 1.6 and λ = 2.5 at drive frequencies of 100 kHz to 500 kHz. It then decreases, and the ratio becomes almost constant above λ = 20. In other words, above λ = 20, the ratio is more likely to increase the volume of the core body 10 than to reduce copper loss. From this, it can be said that even when a single wire is used as the conductor of the coil 30, it is preferable that 1.6≦λ≦20 be satisfied in the magnetic component 1A.

[0058] Next, we will discuss the dependency of the second gap L2. Here, we examined the characteristics of the magnetic component 1A when the second gap L2 was varied based on the above specifications. <λ and Copper Loss> Figure 17 is a diagram showing the relationship between λ and copper loss. Figure 17 shows the copper loss of the magnetic component 1A at λ = 0.025 to 62.5, with the second gap L2 as a parameter. Figure 17 shows the results for L2 = 0.05 mm, 0.10 mm, and 0.15 mm, with the drive frequency fixed at 1 MHz. As shown in Figure 17, copper loss decreases linearly up to λ = 1.6, but the rate of decrease tends to slow down thereafter. After λ = 20, copper loss shows a gradual increase. Furthermore, a smaller second gap L2 tends to result in lower loss.

[0059] <λ and Δp / ΔV> Figure 18 shows the relationship between λ and Δp / ΔV. Figure 18 shows Δp / ΔV for the magnetic component 1A at λ = 1.0 to 62.5, with the second gap L2 as a parameter. Figure 18 shows the results for L2 = 0.05 mm, 0.10 mm, and 0.15 mm, with the drive frequency fixed at 1 MHz. Increasing λ reduces copper loss, but as shown in Figure 18, the smaller the second gap L2, the lower the ratio of the copper loss reduction Δp relative to the increase in volume of the core body 10. However, because the second gap L2 affects the product volume, it is desirable to minimize the increase in the second gap L2. As λ increases, the iron loss reduction effect relative to the increase in volume of the core body 10 decreases, and at λ = 20, a point is reached where increasing the volume no longer reduces copper loss. Therefore, there is no benefit to increasing λ above λ = 20. From this, it can be said that it is preferable that 1.6≦λ≦20 in the magnetic component 1A.

[0060] Next, we will show the dependency of the length D of the center leg. Here, we examined the characteristics when the length D of the center leg was changed for the magnetic component 1A with the above specifications. <λ and copper loss> Figure 19 is a diagram showing the relationship between λ and copper loss. In Figure 19, the copper loss in the magnetic component 1A at λ = 0.025 to 62.5 is shown with the length D of the center leg as a parameter. Here, λ = L1 2 / L2 (the same applies below). Figure 19 shows the results when the drive frequency is fixed at 1 MHz, L2 = 0.10 mm, and the center leg length D = 0.0 mm, 1.0 mm, and 1.5 mm. As shown in Figure 19, copper loss decreases linearly up to λ = 1.6 mm, and the rate of decrease tends to slow down thereafter. After λ = 20 mm, copper loss shows a gradual increase when D = 1.5 mm and D = 1.0 mm, and the decrease in copper loss tends to stop when D = 0.0 mm. It can be seen that the loss tends to decrease as the center leg length D increases.

[0061] <λ and Δp / ΔV> Fig. 20 is a diagram showing the relationship between λ and Δp / ΔV. Fig. 20 shows Δp / ΔV for magnetic component 1A at λ = 1.0 to 62.5, with the center leg length D as a parameter. Fig. 20 shows the cases where the drive frequency is fixed at 1 MHz, L2 = 0.10 mm, and the center leg length D = 0.0 mm, 1.0 mm, and 1.5 mm.

[0062] Increasing λ leads to a reduction in copper loss, but as shown in Fig. 20, when the length D of the center leg is 1.0 mm or 1.5 mm, the ratio of the reduction in copper loss Δp to the increase in the volume of the core body 10 is lower when D = 1.5 mm. On the other hand, since the length D of the center leg affects the volume of the product, it is desirable to suppress the increase in the length D as much as possible.

[0063] Furthermore, when the length D of the center leg is 0.0 mm, the second gap L2 between the center leg 11 and the winding core 20 is located outside the coil 30, and is therefore susceptible to the influence of eddy currents.

[0064] As λ increases, the effect of reducing iron loss relative to the increase in volume of the core body 10 decreases, and at λ = 20, a point is reached where increasing the volume no longer reduces copper loss. Therefore, there is no benefit to increasing λ above λ = 20. For this reason, it can be said that it is preferable for the magnetic component 1A to be in the range of 1.6 ≦ λ ≦ 20.

[0065] Next, the change in magnetic permeability due to the second gap L2 will be shown. FIG. 21 is a diagram showing the relationship between the magnetic field and the relative magnetic permeability. FIG. 21 shows the relationship between the magnetic field and the relative magnetic permeability of the magnetic component 1A, with the second gap L2 as a parameter. FIG. 21 shows the cases where L1 is fixed at 0.5 mm and D is fixed at 1.5 mm, and L2 is set to 0.05 mm, 0.10 mm, and 0.15 mm. For reference, FIG. 21 also shows the relationship between the magnetic field and the relative magnetic permeability of the comparative component 2B.

[0066] 21, by varying the second gap L2, it is possible to vary the relative permeability of the magnetic component 1A even when the size and core material are the same. Note that the second gap L2 can be easily and accurately adjusted, for example, by mixing a gap filler into the adhesive when butt-joining the center leg 11 of the core body 10 and the winding core 20.

[0067] Furthermore, since the magnetic component 1A can have a higher relative magnetic permeability than the comparative component 2B, it is easier to reduce the size of the product than the comparative component 2B.

[0068] Next, the change in magnetic permeability depending on the length D of the center leg is shown. FIG. 22 is a diagram showing the relationship between the magnetic field and the relative magnetic permeability. FIG. 22 shows the relationship between the magnetic field and the relative magnetic permeability of the magnetic component 1A, with the length D of the center leg as a parameter. FIG. 22 shows the cases where L1 = 0.5 mm, L2 = 0.1 mm, and D = 0.0 mm, 1.0 mm, and 1.5 mm. For reference, FIG. 22 also shows the relationship between the magnetic field and the relative magnetic permeability of the comparative component 2B.

[0069] 22 , in magnetic component 1A, even when second gap L2 between center leg 11 of core body 10 and winding core 20 is fixed, the relative permeability can be adjusted by varying center leg length D. That is, in magnetic component 1A, at least one of second gap L2 and center leg length D can be adjusted while considering the balance between loss and relative permeability, thereby optimizing the design.

[0070] (Electrical / Electronic Devices) Electrical / electronic devices according to one embodiment of the present invention are devices that incorporate the magnetic component 1 or 1A according to the above-described embodiments. Examples of such electrical / electronic devices include power supply devices equipped with a power switching circuit, a voltage step-up / step-down circuit, a smoothing circuit, etc., and small portable communication devices. The magnetic component 1 or 1A according to this embodiment can achieve low loss, particularly in the high-frequency range of drive frequencies of 100 kHz or higher, making it easy to miniaturize electrical / electronic devices incorporating the magnetic component 1 or 1A.

[0071] As such, according to this embodiment, it is possible to provide magnetic components 1, 1A and electrical / electronic devices that can be made smaller by being compatible with high frequencies, while also being able to increase productivity even with complex core shapes.

[0072] Although the present embodiment has been described above, the present invention is not limited to these examples. For example, the shapes of the core body 10 and the winding core 20 are not limited to those described above and may be other shapes. Furthermore, the materials listed above are merely examples and are not limited to these. Furthermore, those in which a person skilled in the art appropriately adds, deletes, or modifies components of the above-described embodiments, or appropriately combines features of the configuration examples of the embodiments, are also included within the scope of the present invention as long as they include the gist of the present invention.

[0073] REFERENCE SIGNS LIST 1, 1A...magnetic component 2A, 2B, 2C, 2D...comparison component 10...core body 11...middle leg portion 11a...surface 12...side leg portion 13...connection portion 20...winding core 30...coil 102A, 102B...core 112A, 112B...middle leg portion D...length of middle leg portion L1...first gap L2...second gap

Claims

1. A magnetic component comprising a pair of core bodies having a center leg, side legs arranged on either side of the center leg, and a connecting section connecting the center leg and the side legs, a winding core arranged between opposing flat surfaces of the center leg with a second gap L2, and a coil arranged around the winding core with a conductor wound therearound, wherein the winding core is made of a material different from the core body, and is arranged with a first gap L1 between it and the coil, and under operating conditions with a frequency of 100 kHz or more, the material of the winding core has an iron loss three times or less than that of the material of the core body.

2. The magnetic component according to claim 1, wherein the magnetic material of the core body is made of ferrite, and the magnetic material of the winding core is made of a soft magnetic metal material.

3. When the first gap is L1 and the gap between the center leg portion and the winding core is L2, 1.6≦L1 2 2. The magnetic component according to claim 1, wherein / L2≦20.

4. The magnetic component according to claim 3, wherein the winding core is divided into two or more parts.

5. The magnetic component according to claim 1, wherein the driving frequency is 1 MHz or more.

6. The magnetic component according to claim 2, wherein the metallic portion of the soft magnetic metal material is made of an amorphous phase.

7. A magnetic component according to claim 2, wherein the metallic portion of the soft magnetic metal material is composed of an amorphous phase and a crystalline phase.

8. An electric or electronic device in which a magnetic component according to any one of claims 1 to 7 is mounted.