JP2018156974A - Three-phase tripod magnetic core and three-phase tripod inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-phase tripod magnetic core and three-phase tripod inductor capable of equalizing excitation inductance of each phase with low loss.SOLUTION: A three-phase tripod magnetic core includes three legs (2, 2A, ..., and 2Q) composed of leg members each including a winding portion (3a) around which a conductive wire is wound, and that forms a space (16) in which coil windings (8) to be formed on the winding portions are arranged to be separated from each other without mutual interference and joints (4-4, 4A-4A, ..., and 4Q-4Q) directly joined to each other or indirectly joined to each other via another member at a point where one of the leg members constituting the leg meets the other leg member such that the three legs electromagnetically communicate with each other.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a three-phase tripod magnetic core as a core of an inductor and a transformer and a three-phase tripod inductor using the same, and more particularly to an inductor incorporated as an AC filter in a three-phase PWM inverter circuit such as an uninterruptible power supply (UPS). .

  For example, as described in Non-Patent Document 1, a conventional three-phase inductor uses the design concept of a three-phase transformer in a basic design as it is, so that its structure approximates that of a three-phase transformer. ing.

  In designing a three-phase transformer, it is important to make the excitation current smaller than the load current. In the three-phase transformer, when the exciting current is sufficiently small, even if the exciting current is somewhat unbalanced, it is considered that there is substantially no problem. For this reason, in the design of the three-phase transformer, it is not necessary to match the exciting currents of the respective phases, and even if there is a slight difference between the three-phase exciting inductances, it is ignored as a practical problem.

  On the other hand, equalization of current ripple is an important point in the design of a three-phase inductor. Therefore, for the design of a three-phase inductor, it is required to make the inductance between terminals of each winding as uniform as possible.

IEEE TRANSACTIONS ON POWER ELECTRONICS VOL.29, NO.7, 3657-3668, JULY 2014, “Loss Estimation Method for Three-Phase AC Reactors of Two Types of Structures Using Amorphous Wound Cores in 400-kVA UPS”, Kenichi Onda et al . 2015 IEEJ Industrial Applications Division Proceedings I-103-106, Development of Matrix Converter with Input / Output Sine Wave Filters, Filter Miniaturization Using SiC, Yasunori Furukawa, etc., Yaskawa Electric Co., Ltd.

  However, conventional three-phase inductors used in uninterruptible power supplies (UPS) are designed for three-phase inductors in accordance with the design philosophy of three-phase transformers, so low loss is calculated using bias current and magnetic circuit calculations. Insufficient study of technology. For this reason, in a design in which each leg generally used in a three-phase transformer has a uniform magnetic path cross-sectional area, the magnetic flux density of the central leg is likely to be saturated, and the temperature rise due to loss increases. In a conventional three-phase inductor that is assumed to be composed of the same magnetic material, three legs are arranged side by side in parallel, and each leg is designed to have an equal cross-sectional area. If this is done, the inductance between terminals of each winding will not be equal. This is because the magnetic path lengths of the legs are inevitably not equal in the conventional structure.

  As described above, in the conventional three-phase inductor, the three-phase excitation inductance cannot be equalized, and the current ripples of the windings cannot be equalized.

  Further, in actual circuit design of a three-phase power supply, for example, as described in Non-Patent Document 2, there are many examples in which three single-phase inductors are connected as input / output filter reactors. A unit in which three single-phase inductors are connected side by side is relatively large compared to other device components. In such a circuit configuration including a large number of components, one component occupying a lot of space has a problem that the power supply device is increased in size.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a small three-phase tripod magnetic core and a three-phase tripod inductor having excellent heat dissipation and low loss.

  The three-phase tripod magnetic core according to the present invention is composed of a leg member including a winding portion around which a conducting wire is wound, and the coil windings to be formed in the winding portion are arranged apart from each other without interfering with each other. The three legs that form a non-interfering space and the one leg member that constitutes the leg are directly connected to each other so that the three legs are electromagnetically connected to each other. A joint portion joined or indirectly joined via another member.

  According to the present invention, a small three-phase tripod magnetic core and a three-phase tripod inductor having excellent heat dissipation and low loss are provided.

  The magnetic core and the inductor of the present invention have a structure in which a sufficient non-interference space is formed between the tripods or between the three winding portions, so that heat is easily dissipated to the outside. The tripod temperature balance is very good without accumulation. Moreover, since the excitation inductance of each phase is equalized, the loss is reduced and the efficiency is increased. Furthermore, since the inductor of the present invention is small and has low loss, the design flexibility can be greatly increased in the design of a power circuit such as a three-phase PWM inverter circuit of an uninterruptible power supply (UPS).

The perspective view which shows three U-shaped leg members which comprise the three-phase tripod magnetic core of Example 1 which concerns on 1st Embodiment. The perspective view which shows the three-phase tripod magnetic core (three-piece joining core) of Example 1. FIG. The plane schematic diagram for demonstrating the effect | action of a three-phase tripod magnetic core. The flowchart which shows the manufacturing method of the three-phase tripod magnetic core (three-piece joining core) of Example 1, and a three-phase tripod inductor. 1 is a perspective view showing a three-phase tripod inductor of Example 1. FIG. (A) is an exploded plan view showing a C-shaped leg member of Example 2, (b) is an exploded front view showing a C-shaped leg member of Example 2, and (c) shows a C-shaped leg member of Example 2. FIG. FIG. (A) is a top view which shows the magnetic core of Example 2, (b) is a front view of the magnetic core of Example 2, (c) is a perspective view of the magnetic core of Example 2. FIG. FIG. 6 is a schematic plan view showing an inductor of Example 2. (A) is a top view which shows the magnetic core of Example 3, (b) is a plane schematic diagram which shows the inductor of Example 3. FIG. (A) is a top view which shows the magnetic core of Example 4, (b) is a plane schematic diagram which shows the inductor of Example 4. FIG. (A) is a top view which shows the U-shaped leg member and insert member which comprise the three-phase tripod magnetic core (5-piece joining core) of Example 5 which concerns on 2nd Embodiment, (b) is the magnetic core of Example 5. Plan view, (c) is a schematic plan view of the inductor of Example 5. FIG. 10 is a flowchart showing a method for manufacturing the three-phase tripod magnetic core and the three-phase tripod inductor of Example 5. (A) is a disassembled front view which shows the C-shaped leg member and insert member of Example 6, (b) is an exploded perspective view which shows the C-shaped leg member and insert member of Example 6. FIG. (A) is a top view which shows the magnetic core of Example 6, (b) is a plane schematic diagram which shows the inductor of Example 6. FIG. (A) is an exploded plan view showing an insert member and a C-shaped leg member of Example 7, (b) is an exploded front view showing an insert member and a C-shaped leg member of Example 7, and (c) is an example. The disassembled perspective view which shows 7 insert members and a C-shaped leg member. (A) is a top view which shows the magnetic core of Example 7, (b) is a plane schematic diagram which shows the inductor of Example 7. FIG. (A) is a top view which shows the magnetic core of Example 8, (b) is a plane schematic diagram which shows the inductor of Example 8. FIG. (A) is a perspective view showing an inductor (5-piece bonded core) of Example 9, (b) is a perspective view showing an inductor (3-piece bonded core) of Example 10, and (c) is an inductor of Example 11 ( The perspective view which shows a 2 piece joining core. 10 is a flowchart illustrating a manufacturing method of a magnetic core and an inductor according to a ninth embodiment. The flowchart which shows the manufacturing method of the three-phase tripod inductor (winding iron core tripod core) of Example 12. The flowchart which shows the manufacturing method of the three-phase tripod inductor of Example 13 (combination of a three-leaf plate type insert member without a hole + coil bobbin). The flowchart which shows the manufacturing method of the three-phase tripod inductor (combination of a perforated three-leaf board type insert member + coil bobbin) of Example 14. The flowchart which shows the manufacturing method of the magnetic core (2 piece joining core) and inductor (insulation coating direct winding type) of Example 15 which concerns on 3rd Embodiment. 19 is a flowchart showing a manufacturing method of a magnetic core and an inductor (coil bobbin built-in type) in Example 16. (A) is a front view which shows a pair of half tripod core member of Example 17, (b) is a perspective view which shows a pair of half tripod core member of Example 17. FIG. (A) is a front view which shows the magnetic core of Example 17, (b) is a perspective view which shows the magnetic core of Example 17, (c) is a plane schematic diagram which shows the inductor of Example 17. FIG. A circuit diagram of a three-phase inverter incorporating a three-phase tripod inductor. The plane schematic diagram which simplifies and shows the magnetic core wound, in order to demonstrate the effect | action of a three-phase tripod inductor. The equivalent circuit diagram of a three-phase tripod inductor.

  Important terms in this specification are defined below.

  “Magnetic anisotropy” refers to crystal magnetic anisotropy, shape magnetic anisotropy and induced magnetic anisotropy in a broad sense, or a combination of two or more. Say.

  The “material without magnetic anisotropy” refers to a magnetic material having a property that it is not magnetized in a specific direction or difficult to be magnetized in a magnetic field.

  “There is virtually no gap in the joint” means that even though microscopic voids (voids) and voids (clearance) are present at the joint of the magnetic leg, It means that the joint is electromagnetically coupled without causing electromagnetic loss. Specifically, it means that the magnetic leg portions are magnetically closely coupled to each other without causing leakage magnetic flux at the joint portion of the magnetic leg portions.

  Hereinafter, various preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  First, the magnetic core and inductor according to the first embodiment and the manufacturing method thereof will be described.

(First embodiment)
In the first embodiment, a magnetic core and an inductor according to four examples and a manufacturing method according to the two examples will be described. The three-phase tripod magnetic core according to the first embodiment is formed by joining three powder magnetic core members as shown in FIGS. 2, 7, 9, 10, and 18 (b). In addition, the three-phase tripod inductor according to the first embodiment has a coiled conductor on each tripod of the three-piece bonded core, as shown in FIGS. 5, 8, 9, 10, and 18 (b). Wrapped around.

  FIG. 27 shows a three-phase inverter circuit including the three-phase tripod inductor of this embodiment.

  In an uninterruptible power supply (UPS), an ACL and a capacitor are inserted into the AC output circuit to obtain a waveform close to a sine wave. In addition, ACLs are also used in motor inverters for the purpose of preventing abnormal heat generation and unnecessary noise from high frequency ripple. The three-phase tripod inductor 20 (20A to 20Q) of the present embodiment is connected between the power switching element circuit and various loads in the three-phase inverter circuit, and functions as an AC filter.

  The three-phase inverter circuit shown in the figure is designed to have a three-phase three-wire configuration that operates by PWM modulation. Unlike the single-phase inductor, the inductance value between the terminals of the three-phase tripod inductor under the three-phase PWM inverter excitation is a value including both the self-inductance and the mutual inductance.

The inductor 10 according to the first embodiment has an axisymmetric structure in which a tripod branches at 120 degrees. Because of the axially symmetric structure, in the inductor 10 of the first embodiment, the tripod magnetic leg cross-sectional area is the same (S _A = S _B = S _C ), and the number of turns of the tripod coil is the same (N _A = N _B = N _C ).

  Next, the generation principle of the excitation inductance of each phase of the three-phase tripod inductor and the theoretical basis necessary for equalizing them will be described with reference to FIGS.

First, a condition is derived in which the current ripples flowing in the three-phase tripod inductor are the same. If it is a symmetrical three-phase load, the voltage of each phase of the three-phase tripod inductor is given by the following equations (1) to (3), and the current is given by the following equation (4). In order to make the current ripple that flows through each phase inductor the same even if the magnetic leg cross-sectional area of the three-phase tripod inductor is changed, the inductance value L _TotalA of the A-phase, B-phase, and C-phase inductors during three-phase inverter operation , L _TotalB and L _TotalC must be aligned.

  Next, the procedure for deriving the inductance of each phase will be described.

When the equivalent circuit of the three-phase tripod inductor shown in FIG. 27 is used, the magnetic flux of each magnetic leg is given by equations (5) to (7).

  Here, the symbol la indicates the effective magnetic path length of the center leg A portion (I-shaped), and the symbols lb and lc indicate the effective magnetic path length of both legs / lateral legs (U-shaped) of the three-phase tripod inductor core.

The flux linkage _{ψ A = N A φ A,} ψ B = N B φ B, When ψ _C = N _C φ _C is given by equation (8).

Since the mutual inductance has symmetry, the above equation (8) can be expressed by the following equation (9).

In the 120-degree symmetric structure, R _A = R _B = R _C , L _A = L _B = L _C = L and M _AB = M _BC = M _CA = M, so the above equation (9) is It is rewritten as (10).

At this time, the inductor voltages ν _LA , ν _LB , ν _LC of each phase are expressed by the following equations (11) to (13) using the inductor currents i _LA (t), i _LB (t), i _LC (t). Given each.

The above equations (11) to (13) can be rewritten as the following equations (14) to (16) using Kirchhoff's law (i _LA (t) + i _LB (t) + i _LC (t) = 0) Can do.

  From these formulas (14) to (16), the combined inductance value between the terminals is given by the sum (L + M) of the self-inductance and the mutual inductance.

  Next, the constituent materials constituting the inductor according to the first embodiment will be described.

[Magnetic powder material]
Magnetic powder materials to be included in the tripod core include Fe-Si alloys (containing 3-8% Si), Fe-based amorphous (Fe-Si-Cr-B, Fe-Si-Cr-P), permalloy, as shown in Table 1. High flux (50% Fe-50% Ni), Fe-Si-Al alloy, Co-based amorphous (Co-Fe-Si-B), silicon steel (containing 3 to 6.5% Si), Fe-based nanocrystalline soft magnetism Materials (Fe-Si-B-Nb-Cu, Fe-Zr-B-Cu, Fe-Co-Zr-B-Cu), silicon steel (containing 3 to 6.5% Si), Fe-based amorphous magnetic materials (Fe- Any magnetic powder of B-Si-C or Fe-B-Si) can be used. The average particle diameter of these magnetic powder materials may be slightly different depending on the material and temperature / pressure conditions during molding, but is generally in the range of 5 to 100 μm. Furthermore, the average particle diameter of the magnetic powder material excluding the Fe-based nanocrystalline soft magnetic material can be in the range of 50 to 100 μm.

[Molding aid]
As a molding aid used for molding the magnetic core, any one or both of an inorganic nonmagnetic binder and an organic resin binder shown in Table 2 can be used in combination. For the inorganic nonmagnetic binder, either a silicone resin or water glass can be used. As the organic resin binder, any of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), methyl cellulose, water-soluble acrylic, paraffin, glycerin, and polyethylene glycol can be used (Table 2).

[Conductor]
The conducting wire is wound around the tripod core of the inductor to form a coil winding. The conducting wire is pure Cu wire (0.9 mm diameter) covered with an insulating coating, and the coating of JIS standard number C3202 is thick (1 type: 0.025 mm) and thin (2 types: 0.0. 017 mm) can be used.

[adhesive]
The adhesive is applied to the joint surface of the core member in order to join the plurality of core members. As the adhesive, a heat-resistant epoxy adhesive or a heat-resistant ceramic adhesive can be used. Examples of heat-resistant epoxy adhesives include EW2010, EW2020, EW2030 and EW2034 from 3M Japan, Alemcobond 631, Alemcobond 526N, Alemcobond 657, Alemcobond 657, Alemcobond 570, Alemcobond 2200, Alemcobond 2300 and Alemcobond 2330, Nagasekem Tex Corporation's one-part epoxy adhesives XNR3503, XNR3505, XNR3506, XN1244, XN1278, Dutronic Co125 and DulalcoNM25 from Cotronics, etc. can be used. As the heat-resistant ceramic adhesive (heat-resistant inorganic adhesive), for example, 3M TB3732 manufactured by 3M Japan Co., Ltd., Durabond 950 manufactured by Kotronics, Aron ceramic manufactured by Toagosei Co., Ltd., or the like can be used.

[Example 1]
Next, the magnetic core and inductor of Example 1 according to this embodiment will be described.

  The magnetic core 10 of the first embodiment is manufactured by joining three leg members 2 having the same shape. An Fe—Si—Al-based alloy (HK material of Toho Zinc Co., Ltd.) was used as the magnetic powder material of the leg member 2 of Example 1. In Example 1, PVA and water glass were used as molding aids for the leg member 2.

As shown in FIG. 1, the leg member 2 is formed in a U-shape when viewed from the side. The leg member 2 has a straight winding portion 3a at the center portion and end portions 3b on both sides thereof. The winding part 3a is a main part of the leg member 2 around which the conducting wire is wound, and has a rectangular cross section with a uniform cross-sectional area S _A (= S _B , S _C ).

  Two joining surfaces 4 are formed on each end portion 3b of the leg member. The apex angle around the central axis 30 of the two adjacent joint surfaces 4 at the end 3b is 120 degrees. Each joining surface 4 is finished to a sufficiently flat and smooth surface by machining in order to join the joining surfaces with an adhesive without substantial gaps. EW2010 of 3M Japan Co., Ltd. was used as an adhesive.

  As shown in FIG. 2, in the magnetic core 10 of the first embodiment, the three leg members 2 are arranged symmetrically around the central axis 30. In the magnetic core 10, the joint surfaces 4 are tightly joined together, and as a result, six joint portions 4-4 having substantially no gap are obtained. Since all the joints 4-4 are substantially free of gaps, the three leg members 2 are in an electromagnetically closely coupled state. For this reason, when a conducting wire is wound around the winding part 3a of each leg and the three coil windings 8 are energized, the excitation inductances of the respective phases become uniform, and high-efficiency performance with low loss can be obtained.

The size of each part of the magnetic core 10 of Example 1 is listed. Leg length (core height) is 20mm, leg width is 6mm, leg thickness is 2.5mm, winding length is 15mm, end length is 8mm, leg breakage area _{S a (= S B, S} C) is 12.5 mm ^2, the total area a _aS junction is 25.5 mm ^2.

FIG. 5 shows the inductor 20 according to the first embodiment in which a conducting wire is wound around each winding portion 3a of the magnetic core. In the inductor 20, the three leg members 2 constituting the leg portions are arranged symmetrically around the central axis 30. A non-interference space 16 is provided in the central region of the inductor 20 so that the coil windings 8 do not interfere with each other. The non-interference space 16 provides sufficient clearance so that the three coil windings 8 do not contact each other. The size of the non-interference space 16 is determined according to the number of windings N _A , N _B , N _C of the conducting wire and the cross-sectional shape of the leg member. In this embodiment, in order to make the non-interference space 16 sufficiently large, the leg member is U-shaped, and the winding portion 3a of the leg member is kept away from the central axis 30.

  Table 5 shows an example of circuit constants of the three-phase PWM inverter in which the inductor 20 of the first embodiment is incorporated.

  Next, a method for manufacturing the magnetic core and the inductor of the present invention will be described. The manufacturing method of the present invention includes a method of insulatingly coating a magnetic core (core) as shown in FIG. 4 and a method of inserting the core into an insulating case, or a method of winding a lead wire directly around the magnetic core as shown in FIG. There are various embodiments such as a method of winding a conducting wire around a bobbin as shown in FIG. Among them, as a first embodiment, a method for insulatingly coating a core and a method for inserting the core into an insulating case will be described with reference to FIG. First, the manufacturing method 1 for insulating coating the core will be described.

[Production Method 1]
Next, a method for manufacturing the three-phase tripod magnetic core and the three-phase tripod inductor of Example 1 will be described.

  Magnetic powder for preparing a tripod member is prepared (step S1). Various materials shown in Table 1 can be used as the magnetic powder. The magnetic powder is a spherical fine particle having a substantially uniform particle size. The optimum particle diameter of the magnetic powder varies depending on the material and the manufacturing method, but the average particle diameter of the magnetic powder for producing the magnetic core of the present invention is, for example, in the range of 50 to 100 μm in consideration of properties such as press formability. It is desirable to do. However, a magnetic particle material such as a nanocrystalline soft magnetic material may have an average particle size of less than 50 μm.

  A molding aid is mixed with the magnetic powder (step S2). As the molding aid, various materials shown in Table 2 can be used.

  A mold having a U-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed at a predetermined pressure and room temperature (step S3). In the present embodiment, the press molding is performed in a cold manner. However, as another method, it is possible to perform the press molding in a warm or hot state in which preheating is performed.

  The press-molded product is taken out from the mold, and both end portions of the press-molded product are each end-ground to the shape shown in the figure (step S4). Specifically, both ends of the U-shaped press-formed product are ground into an isosceles triangle shape having an apex angle of 120 degrees, and two surfaces following the two sides sandwiching the apex angle are finished smoothly. Thereby, the joint surface 4 is obtained in the both ends of a press molded product. The surface roughness of the joint surface 4 is desirably 5 μm or less in terms of arithmetic average roughness Ra specified in JIS B0601 (2001).

  The press-molded product is placed in a heat treatment furnace and heat treated under conditions of 100 to 500 ° C. × 2 to 5 hours (step S5). As a result, part or all of the molding aid is melted, the melt enters the gaps between the magnetic powder particles, and the bonding force between the magnetic powder particles is strengthened. In this example, the magnetic powder material of the leg member (3 to 8% Si-containing Fe—Si alloy) was heat-treated at 100 to 500 ° C., but other magnetic materials (permalloy, etc.) other than iron powder and amorphous powder were used. ) Is preferably heat-treated at 500-1000 ° C.

  After taking out the U-shaped leg member 2 from the heat treatment furnace and lowering the temperature to near room temperature, the surface of the leg member 2 (excluding the bonding surface 4) and at least the surface of the winding portion 3a are insulatively coated (step S6). -1). For this insulating coating, a paint containing an insulating resin such as an epoxy resin or a urethane resin can be used. As the insulating epoxy resin paint, for example, either TVB2166 or TVB2166B (black) of Kyocera Corporation can be used. Further, as the insulating urethane resin paint, for example, any one of KU-7002, KU-7008, KU-5550, and KU-5550-9 manufactured by Hitachi Chemical Co., Ltd. can be used.

A conductive wire is directly wound around each of the winding portions 3a coated with insulation to produce three coil windings 8 (step S7-1). The number of turns N _A , N _B , N _C of the three coil windings 8 is the same.

  An adhesive (for example, EW2010 of 3M Japan Co., Ltd.) is applied to each of the joint surfaces 4 of the leg members, and the three leg members 2 are adhesively joined to each other (step S8). Thereby, the three leg members 2 are electromagnetically coupled without being insulated from each other. In this embodiment, the leg members are bonded to each other by a method of applying an adhesive to the bonding surface, but the present invention is not limited to this bonding method, and a liquid adhesive is applied to the bonding surface. The leg members may be joined to each other by a method of impregnation. Such an impregnation bonding method is particularly effective for a porous material having a large porosity.

  In the joining and assembling step S8, the three leg members 2 are positioned with high accuracy and are brought into close contact with each other so that no gap is formed between the joining surface 4 of one leg member and the joining surface 4 of the other leg member. A dedicated jig (not shown) can be used for positioning at the time of joining. As a result, as shown in FIG. 5, three joint portions 4-4 are formed which are joined substantially without a gap.

  Since these joint portions 4-4 have substantially no gap, the three leg members 2 are electromagnetically closely coupled to each other. For this reason, when the three coil windings 8 are energized, the excitation inductance generated in each phase is equalized, and a low-loss and high-efficiency inductor 20 is obtained.

The self-inductance of each phase was actually measured for the inductor of this example. When specifically to measure incorporation of the inductor of the present embodiment to a power supply circuit having the circuit constants in Table 5, each phase of the self-inductance of when energized by a high-precision power meter (PPA5530 of NEWTONS4th Inc.), respectively L _A = 65.753 μH, L _B = 65.203 μH, L _C = 67.861 μH. From these results, the inductor of this example has substantially the same self-inductance of the A-phase, B-phase, and C-phase, and the inductance between terminals of each phase under the three-phase excitation is substantially equal, and the three-phase excitation It has been demonstrated that the inductance is evenly balanced.

  In the joining and assembling step S8, the winding portion 3a of each leg member is located away from the central axis 30, and as a result, a non-interference space 16 is formed in the central portion of the inductor core. The non-interference space 16 is defined by the size of the inscribed circle inscribed in the tripod of the inductor core. The radius r of the inscribed circle is preferably at least three times the thickness t of the coil winding 8 (r ≧ 3t). The presence of the non-interference space 16 allows the three leg members 2 to be joined and assembled without the three coil windings 8 colliding with each other. Thereby, the inductor 20 shown in FIG. 5 is obtained.

  In the present embodiment, the leg member is joined to the insert member after the conducting wire is wound around the leg member, but the conducting wire may be wound around the leg portion of the core after joining the leg member and the insert member.

[Production Method 2]
Next, the manufacturing method 2 which covers each leg member with an insulating case cover will be described.

  The manufacturing process from step S1 to step S5 of manufacturing method 2 is substantially the same as manufacturing method 1 described above. After taking out the U-shaped leg member 2 from the heat treatment furnace and lowering the temperature to near room temperature, the leg member 2 is inserted into the insulating case cover 5 (step S6-2).

  The insulating case cover 5 is formed in a similar shape slightly larger than the leg member 2 so that the leg member 2 can be inserted, and is formed by combining a pair of halved parts divided along the longitudinal direction. It is. As the material of the insulating case cover 5, an insulating resin such as polyethylene terephthalate (PET), liquid crystal polymer (LPC), polybutylene terephthalate (PBT), polyamide (PA), or polycarbonate can be used. As the insulating polyethylene terephthalate (PET), for example, Rynite (registered trademark) manufactured by DuPont can be used. Moreover, for example, Panlite (registered trademark) manufactured by Teijin Limited can be used as the insulating polycarbonate resin. In addition, you may make it insert the leg member 2 which apply | coated the insulating coating material to the coil | winding part 3a in the insulating case cover 5. FIG.

  The insulating case cover 5 covers the outer surface of the leg member 2 except for the joint surface 4. That is, when the insulating case cover 5 is attached to the leg member 2, most of the outer surface of the leg member 2 is covered with the insulating case cover 5, and only the joint surface 4 is exposed.

A conducting wire is wound around each of the winding portions 3a covered with the insulating case cover 5 to produce three coil windings 8 (step S7-2). The number of turns N _A , N _B , N _C of each coil winding 8 is the same.

  An adhesive is applied to each joint surface 4 of each leg member, and the three leg members 2 covered with the insulating case cover 5 are joined to each other (step S8). EW2020 of 3M Japan Co., Ltd. was used as an adhesive.

  In this embodiment, the three leg members are simply bonded and fixed with an adhesive. However, the fixing of the three leg members is further strengthened by winding an insulating tape around the outer periphery of the three-phase tripod magnetic core. You can also.

  Further, the above-described insulating case cover is not limited to this example, and can be used in other embodiments and other examples.

  Next, other examples 2, 3, and 4 according to the first embodiment will be described with reference to FIGS.

[Example 2]
As shown in FIGS. 7A, 7B, and 7C, the magnetic core 10A of the second embodiment is manufactured by joining three leg members 2A having the same shape. The same magnetic powder material as in Example 1 was used for the leg member 2A in Example 2. As shown in FIGS. 6B and 6C, the leg member 2A of the second embodiment is formed in a C-shape when viewed from the side and has a curved winding portion 3a. Two joining surfaces 4A are formed on each end of the winding portion 3a. The two joining surfaces 4A are mechanically ground so as to form an isosceles triangle shape having an apex angle of 120 degrees. The surface roughness and flatness of the joint surface 4A are finished to such an extent that no gaps are substantially generated in the three joint portions 4A-4A after bonding. EW2020 of 3M Japan Co., Ltd. was used as an adhesive.

An insulating resin liquid is applied to the surface of the magnetic core 10A shown in FIG. 7 to insulate the magnetic core 10A. A conducting wire is wound around each of the winding portions 3a of the magnetic core coated with insulation. The number of turns N _A , N _B , N _C of the three coil windings 8 is the same. When the three coil windings 8 are formed, the three-phase tripod inductor 20A of Example 2 shown in FIG. 8 is obtained.

[Example 3]
In the magnetic core 10B of the third embodiment, as shown in FIG. 9A, one first leg member 2B1 and two second leg members 2B2 having different shapes at both ends are joined to each other. It will be. The same magnetic powder material as in Example 1 was used for the leg members 2B1 and 2B2 in Example 3. The first leg member 2B1 is formed in a U-shape when viewed from the side, and has a straight winding portion 3a that is not curved. Two joining surfaces 4B1 are formed at both ends of the winding part 3a. The two joining surfaces 4B1 are machine-ground so as to form an isosceles triangle shape having an apex angle of 60 degrees.

  The second leg member 2B2 is formed in a U-shape when viewed from the side, and has a straight winding portion 3a. Bonding surfaces 4B1 are formed at both ends of the winding portion 3a. The joining surface 4B1 is machined so as to be a flat surface. The surface roughness and flatness of the first and second joint surfaces 4B1 and 4B2 are finished to such an extent that no gaps are substantially generated in the four joint portions 4B1-4B2 after bonding.

  The magnetic core 10B of Example 3 is obtained by joining the joint surface 4B2 of the second leg member to each of the joint surfaces 4B1 of the first leg member. EW2020 of 3M Japan Co., Ltd. was used as an adhesive.

An insulating resin liquid is applied to the surface of the magnetic core 10B shown in FIG. 9A to insulate the magnetic core 10B. A conducting wire is wound around each of the winding portions 3a of the magnetic core coated with insulation. The number of turns N _A , N _B , N _C of each coil winding 8 is the same. When the three coil windings 8 are formed, the three-phase tripod inductor 20B of Example 3 shown in FIG. 9B is obtained.

[Example 4]
As shown in FIG. 10A, the magnetic core 10C according to the fourth embodiment is formed by joining a first leg member 2C1 and two second leg members 2C2 having different shapes at both ends. is there. The same magnetic powder material as in Example 1 was used for the leg members 2C1 and 2C2 in Example 4. The first leg member 2C1 is formed in a U-shape when viewed from the side, and has a straight winding portion 3a. Bonding surfaces 4C1 are formed at both ends of the winding portion 3a. The joint surface 4C1 is machined so as to be a flat surface.

  The second leg member 2C2 is formed in a U-shape when viewed from the side, and has a straight winding portion 3a that is not curved. Two joint surfaces 4C2 and 4C3 are formed at both ends of the winding portion 3a. The two joint surfaces 4C2 and 4C3 are mechanically ground so as to form an unequal triangular shape with an apex angle of 90 degrees. The surface roughness and flatness of the first to third bonding surfaces 4C1, 4C2, and 4C3 are finished to such an extent that no gaps are substantially generated in the six bonded portions 4C1-4C2 and 4C3-4C3 after bonding. .

  First, the joint surfaces 4C3 of the two second leg members are joined together, and then the joint surface 4C1 of the first leg member and the joint surface 4C2 of the second leg member are joined, thereby the magnetic core 10C of the fourth embodiment. Is obtained. EW2020 of 3M Japan Co., Ltd. was used as an adhesive.

An insulating resin liquid is applied to the surface of the magnetic core 10C shown in FIG. 10A to insulate the magnetic core 10C. A conducting wire is wound around each of the winding portions 3a of the magnetic core coated with insulation. The number of turns N _A , N _B , N _C of each coil winding 8 is the same. When the three coil windings 8 are formed, the three-phase tripod inductor 20C of Example 4 shown in FIG. 10B is obtained.

(Second Embodiment)
Next, the magnetic core (5-piece bonded core) and inductor according to the second embodiment and their manufacturing methods will be described.

  The magnetic core of the second embodiment is formed by joining five magnetic pieces. The magnetic core of the second embodiment is shown in FIGS. 11, 12, 13, 15, 16, 16, 17, 18 (a), 19, 20, 21, and 22, respectively. Three leg members 2D to 2M are joined to each other via a pair of insert members 6 and 6F to 6M. Further, the inductor according to the second embodiment has 5 as shown in FIGS. 11, 12, 13, 15, 16, 17 (a), 19, 20, 21, and 22, respectively. Each wire is wound around an insulated tripod of a piece-joined core.

[Example 5]
Next, the magnetic core and inductor of Example 5 according to Embodiment 2 will be described with reference to FIGS.

  As shown in FIGS. 11A and 11B, in the magnetic core 10 </ b> D of the fifth embodiment, the pair of insert members 6 are arranged in the center, and the three leg members 2 </ b> D are axially arranged around the insert members 6. It is arranged. The insert member 6 is a regular triangular prism having three joint surfaces 7. The pair of insert members 6 are spaced apart from each other so that the central axis 30 passes through the center of the regular triangular prism. An Fe-based nanocrystalline soft magnetic material having a composition of Fe—Si—B—Nb—Cu was used as the magnetic powder material of the insert member 6. Fe-based nanocrystalline soft magnetic material is a magnetic anisotropy having a mixed structure in which Fe-based amorphous alloy is crystallized to a very small nanosize, and nanocrystal grains of randomly oriented ferromagnetic phase are dispersed in the amorphous phase. There is no material. Moreover, silicone resin and PVA were used as a molding aid for the insert member.

  The three leg members 2D are formed in a U-shape when viewed from the side, and have straight winding portions 3a that are not curved. Pure iron powder having a purity of 97% or more was used as the magnetic powder material for the leg members. Moreover, PVA and water glass were used as a shaping | molding adjuvant of a leg member. Joining surfaces 4D are formed at both ends of the winding portion 3a. The joining surface 4D is machined so as to be a flat surface.

  The surface roughness and flatness of the joint surfaces 4D and 7 are finished to such an extent that no gaps are substantially generated in the six joint portions 4D-7 after bonding. By joining the joint surfaces 4D of the three leg members to the joint surfaces 7 of the two insert members, the magnetic core 10D of Example 5 is obtained. EW2030 manufactured by 3M Japan Ltd. was used as an adhesive.

The size of each part of the magnetic core 10D of Example 5 is listed. The length of the leg is 45 mm, the width of the leg is 15 mm, the thickness of the leg is 7.5 mm, the length of the winding is 30 mm, and the cross-sectional area S _A (= S _B , S _C ) of the leg is 112 .5mm ^2, total area a _aS of joint thickness of 337.5mm ^2, the length of the side of the insert member is 15 mm, the insert member is 7.5 mm.

An insulating resin liquid is applied to the surface of the magnetic core 10D shown in FIG. 11B to insulate the magnetic core 10D. A conducting wire is wound around each of the winding portions 3a of the magnetic core coated with insulation. The number of turns N _A , N _B , N _C of each coil winding 8 is the same. When the three coil windings 8 are formed, the inductor 20D of Example 5 shown in FIG. 11C is obtained.

  Table 6 shows an example of circuit constants of a three-phase PWM inverter in which the inductor 20D of the fifth embodiment is incorporated.

[Production Method 3]
Magnetic powder for preparing the leg member 2D of Example 5 is prepared (step S11-1). Various materials shown in Table 3 can be used as the magnetic powder. A molding aid is mixed with the magnetic powder (step S12-1). As the molding aid, various materials shown in Table 2 can be used. A mold having a U-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed under a predetermined pressure and room temperature (step S13-1).

  The press-molded product is taken out from the mold, and both end portions of the press-molded product are each end-face ground. Thereby, joining surfaces 4D having a desired surface roughness are obtained at both ends of the press-formed product.

  The press-molded product was placed in a heat treatment furnace and heat-treated under conditions of 100 to 500 ° C. × 2 to 5 hours (Step S14-1). As a result, part or all of the molding aid is melted, the melt enters the gaps between the magnetic powder particles, and the bonding force between the magnetic powder particles is strengthened. In this example, the pressed powder of pure iron powder press-formed as the leg member was heat-treated at a temperature of 300 to 500 ° C. Thereby, a leg member 2D having a shape as shown in FIG. 12 is obtained.

The leg member 2D is formed in a U shape when viewed from the side. The leg member 2D has a straight winding portion 3a at the center portion and end portions 3b on both sides thereof. The winding portion 3a is a main part of the leg member 2D around which the conducting wire is wound, and has a rectangular cross section with a uniform cross-sectional area S _A (= S _B , S _C ).

After the leg member 2D is taken out from the heat treatment furnace and the temperature is lowered to near room temperature, the surface of the leg member 2D (excluding the bonding surface 4D) and at least the surface of the winding part 3a are insulatively coated (step S15-1). A conductive wire is directly wound around each of the winding portions 3a coated with insulation to produce three coil windings 8 (step S16). The number of turns N _A , N _B , N _C of each coil winding 8 is the same.

  Magnetic powder for producing an insert member is prepared (step S11-2). Various materials having no magnetic anisotropy shown in Table 3 can be used as the magnetic powder. The insert member may be the same magnetic powder material as the leg member, or may be a magnetic powder material different from the leg member. Next, the molding aid selected from Table 2 is mixed with the magnetic powder (step S12-2).

  A mold having a regular triangular prism-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press-molded at a predetermined pressure and room temperature (step S13-2).

  The press-molded product is taken out from the mold, and the three sides of the press-molded product are each end-ground. Thereby, the joining surface 7 of desired surface roughness is each obtained on three sides of a press-molded product.

  The press-formed product was placed in a heat treatment furnace and heat-treated under conditions of 100 to 1000 ° C. × 2 to 5 hours (Step S14-2). As a result, part or all of the molding aid is melted, the melt enters the gaps between the magnetic powder particles, and the bonding force between the magnetic powder particles is strengthened. In this example, pressed powder of Fe-based nanocrystalline soft magnetic material press-molded as an insert member was heat-treated at a temperature of 500 to 800 ° C. After the insert member 6 is taken out from the heat treatment furnace and the temperature is lowered to near room temperature, the surface of the insert member 6 (excluding the joining surface 7) is subjected to insulation coating (step S15-2).

  Next, the joining assembly of the three leg members 2D and the two insert members 6 will be described. Adhesive is applied to the joint surface 4D of the leg member and the joint surface 7 of the insert member, respectively, and the three leg members 2D are adhesively joined to the insert member 7 (step S17). EW2030 manufactured by 3M Japan Ltd. was used as an adhesive.

  In the joining and assembling step S17, the distance between the pair of insert members 6 is positioned with high accuracy, and the three leg members 2D are positioned with high accuracy with respect to the pair of insert members 6, and the joint surfaces 4D of the leg members It is made to contact | adhere so that a clearance gap may not arise between the joint surfaces 7 of an insert member. A dedicated jig (not shown) can be used for positioning at the time of joining. As a result, as shown in FIG. 11B, six joint portions 4D-7 are formed which are joined substantially without a gap. Since these joint portions 4D-7 have substantially no gap, the three leg members 2 and the two insert members 6 are electromagnetically closely coupled to each other. For this reason, when the three coil windings 8 are energized, the excitation inductance generated in each phase is equalized, and a low-loss and high-efficiency inductor 20D is obtained.

  Further, in the joint assembly step S17, the non-interference space 16 is formed in the central region of the inductor core. The non-interference space 16 provides sufficient clearance so that the three coil windings 8 do not contact each other. In the present embodiment, in order to make the non-interference space 16 sufficiently large, the leg member 2D is U-shaped, and the winding portion 3a of the leg member is kept away from the central axis 30. The presence of the non-interference space 16 allows the three leg members 2D to be joined and assembled to the insert member 6 without the three coil windings 8 colliding with each other. As a result, the inductor 20D shown in FIG. 11C and FIG. 12 is obtained.

Further, the insulating tape 19 is wound around the outer periphery of the inductor 20D, and the inductor constituent member is firmly fixed by taping (step S18).

[Example 6]
The magnetic core 10E of Example 6 is produced by joining three leg members 2E having the same shape to a pair of insert members 6 as shown in FIG. The leg member 2E and the insert member 6 are respectively produced according to the manufacturing method 3 described above. As shown in FIGS. 13A and 13B, the leg member 2E of the sixth embodiment is formed in a C-shape when viewed from the side and has a curved winding portion 3a. Various magnetic powder materials shown in Table 3 can be used as the raw material of the leg member 2E. An Fe—Si alloy containing 3 to 8% Si was used as the magnetic powder material of the leg member 2E of Example 6.

  Joining surfaces 4E are formed at both ends of the winding portion 3a of the leg member 2E. The joint surface 4E is mechanically ground so as to be a flat surface.

  The insert member 6 is formed in the shape of an equilateral triangular column, and three side surfaces are opportunity-grinded as the joint surface 7. The surface roughness and flatness of the joint surface 7 are finished to such an extent that no gaps are substantially generated in the six joint portions 4E-7 after bonding.

  As a raw material for the insert member 6, various magnetic powder materials having no magnetic anisotropy shown in Table 3 can be used. In Example 6, Permalloy C (75% Ni—Cu—Mo—Fe alloy) defined in JIS C 2531 (1999) was used as the magnetic powder material of the insert member 6.

An insulating resin solution is applied to the surfaces of the three leg members 2E (excluding the joining surface 4E) and the surfaces of the two insert members 6 (excluding the joining surface 7), and the members 2E and 6 are respectively covered with insulation. To do. Conductive wires are wound around the winding portions 3a of the three leg members coated with insulation. The number of turns N _A , N _B , N _C of each coil winding 8 is the same.

  Adhesives are respectively applied to the joint surface 4E of the leg member and the joint surface 7 of the insert member, and the three leg members 2E are adhesively joined to the insert member 6, respectively. EW2034 manufactured by 3M Japan Ltd. was used as the adhesive.

  When the three leg members 2E and the pair of insert members 6 are joined to each other in this manner, an inductor 20E of Example 6 shown in FIG. 14B is obtained.

[Example 7]
The magnetic core and the inductor according to the seventh embodiment will be described with reference to FIGS. 15 and 16, but the description of the portions where the seventh embodiment overlaps with the above-described sixth embodiment will be omitted.

  In the seventh embodiment, the three leg members 2F are joined through the regular hexagonal column-shaped insert members 6F shown in FIGS. 15A and 15C, so that the magnetic core 10F shown in FIG. Is making.

  The leg member 2F and the insert member 6F are respectively produced according to the manufacturing method 3 described above. Various magnetic powder materials having no magnetic anisotropy shown in Table 3 can be used as raw materials for the insert member 6F. In Example 7, Fe—Si—Al alloy powder (HK material of Toho Zinc Co., Ltd.) is used as the material for the insert member 6F, and Fe—Si alloy powder containing 3-8% Si as the material for the leg member 2F. Was used.

  When the three leg members 2F and the pair of insert members 6F are joined to each other, the magnetic core 10F of Example 7 shown in FIG. 16A is obtained. EW2034 manufactured by 3M Japan Ltd. was used as the adhesive.

[Example 8]
The magnetic core and the inductor according to the eighth embodiment will be described with reference to FIG. 17, but the description of the same portions as the seventh embodiment described above in the eighth embodiment will be omitted.

  In the eighth embodiment, the three leg members 2G are joined via the unequal hexagonal column shaped insert member 6G, and the magnetic core 10F shown in FIG. 17A and the insert member 20F shown in FIG. I am making it.

  In the eighth embodiment, the shape of the insert member 6G is an unequal hexagonal column. That is, without making the lengths of the six sides of the insert member 6G equal, the width W2 of the three sides of the joint surface 7G to which the leg member 2G is joined is made larger than the width W3 of the three sides of the non-joint surface. Yes.

  In the eighth embodiment, by setting the size of the insert member 6G to the relationship of W2> W3, the width of the leg member 2G is expanded, the effective sectional area is increased, the insert member 6G is more compact, and the entire inductor is reduced. Miniaturize.

  As the material of the insert member 6G, various magnetic powder materials having no magnetic anisotropy shown in Table 3 can be used. In Example 8, for example, Fe-based nanocrystalline soft magnetic powder (Fe—Si—B—Nb—Cu) is used as the material of the insert member 6G, and Fe—Si containing 3 to 8% Si as the material of the leg member 2G. A system alloy powder was used.

  Next, a magnetic core and an inductor in which three leg members are disposed asymmetrically with respect to the central axis 30 will be described.

  Three types of inductors similar in outer shape are shown in FIGS. 18 (a), (b), and (c). The inductor 20H in FIG. 18A includes the magnetic core 10H of the ninth embodiment in which five pieces are joined, and the inductor 20I in FIG. 18B includes the magnetic core 10I in the tenth embodiment in which three pieces are joined. The inductor 20J shown in FIG. 18C includes the magnetic core 10J of Example 11 in which two pieces are joined.

  First, the magnetic core and inductor of Example 9 and the manufacturing method 4 for manufacturing them will be described.

[Example 9]
As shown in FIG. 18 (a), in the inductor 20H (magnetic core 10H) of the ninth embodiment, a pair of insert members 6H are arranged in the center, and three leg members 2H are arranged around the insert members 6H. Yes. The insert member 6H is a regular quadrangular prism having four joint surfaces 7H. Leg members 2H are joined to three of these four joining surfaces 7H, respectively. The pair of insert members 6H are spaced apart so that the central axis 30 passes through the center of the regular quadrangular prism. Permalloy A (78.5% Ni-Fe alloy) defined in JIS C 2531 (1999) was used as a magnetic powder material for the insert member 6H. In this example, methylcellulose and water glass were used as molding aids for the insert member 6H. Bonding surfaces 7H are formed on the four side surfaces of the insert member 6H. The joining surface 7H is machined so as to be a flat surface.

  The shape of the inductor 20H (magnetic core 10H) is T-shaped when viewed from the Z-axis (center axis 30) direction, is lattice-shaped when viewed from the Y-axis direction, and is annular when viewed from the X-axis direction.

The leg member 2H is formed in a U shape when viewed from the side. The leg member 2H has a straight winding portion 3a at the central portion and end portions 3b on both sides thereof. The winding portion 3a is a main part of the leg member 2H around which the conducting wire is wound, and has a rectangular cross section with a uniform cross-sectional area S _A (= S _B , S _C ). Pure iron powder having a purity of 97% or more was used as the magnetic powder material of the leg member 2H. In this example, PVB and silicone resin were used as molding aids for the leg member 2H. Bonding surfaces 4H are formed at both ends of the winding portion 3a. The joining surface 4H is machined so as to be a flat surface.

  The surface roughness and flatness of the bonding surfaces 4H and 7H are finished to such an extent that no gaps are substantially generated in the six bonded portions 4H-7H after bonding.

An insulating resin liquid is applied to the surface of the leg member 2H (excluding the bonding surface 4H) to insulate the leg member 2H. A conducting wire is wound around each of the winding portions 3a of the magnetic core coated with insulation. The number of turns N _A , N _B , N _C of the three coil windings 8 is the same.

  The leg member 2H and the insert member 6H are respectively positioned with a dedicated jig, an adhesive is applied to the joint surface 4H of the leg member and the joint surface 7H of the insert member, and both are adhesively joined. EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. Thus, the inductor 20H of Example 9 shown in FIG.

[Production Method 4]
As shown in FIG. 19, the magnetic powder for producing the leg member 2H of Example 9 is prepared (process S21-1). Various materials shown in Table 3 can be used as the magnetic powder. A molding aid is mixed with the magnetic powder (step S22-1). Various materials shown in Table 2 can be used as molding aids.

  A mold having a U-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed at a predetermined pressure and room temperature (step S23-1). A U-shaped press-molded product is taken out from the mold, and both end portions of the press-molded product are each end-face ground. Thereby, the joining surface 4H of desired surface roughness is obtained in the both ends of a press molded product.

  The press-molded product was placed in a heat treatment furnace and heat-treated under the conditions of 100 to 500 ° C. × 2 to 5 hours (Step S24-1). As a result, part or all of the molding aid is melted, the melt enters the gaps between the magnetic powder particles, and the bonding force between the magnetic powder particles is strengthened. Thereby, a leg member 2H having a high magnetic permeability is obtained. The leg member 2H is formed in a U-shape when viewed from the side, and has a straight winding portion 3a that is not curved.

  After taking out the leg member 2H from the heat treatment furnace and lowering the temperature to near room temperature, the surface of the leg member 2H (excluding the bonding surface 4H) and at least the surface of the winding part 3a are insulatively coated (step S25-1).

A conductive wire is directly wound around each of the winding portions 3a coated with insulation to produce three coil windings 8 (step S26). The number of turns N _A , N _B , N _C of the three coil windings 8 is the same.

  Magnetic powder for preparing the insert member is prepared (step S21-2). Various materials having no magnetic anisotropy shown in Table 3 can be used as the magnetic powder. A molding aid is mixed with the magnetic powder (step S22-2). As the molding aid, various materials shown in Table 2 can be used.

  A mold having a regular quadrangular prism-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed under a predetermined pressure and room temperature (step S23-2). A regular quadrangular prism-shaped press-molded product is taken out from the mold, and the side surfaces of the press-molded product are each end-ground. As a result, each of the bonded surfaces 7H having a desired surface roughness is obtained on the press-formed product.

  The press-molded product is placed in a heat treatment furnace and heat treated under conditions of 500 to 1000 ° C. × 2 to 5 hours (step S24-2). After the insert member 6H is taken out from the heat treatment furnace and the temperature is lowered to near room temperature, the surface of the insert member 6H (excluding the joining surface 7H) is insulation-coated (step S25-2).

  Next, the joining assembly of the three leg members 2H and the two insert members 6H will be described. The leg member 2H is covered with insulation except for the joint surface 4H, and a coil winding 8 is wound around the winding portion 3a. Adhesive is applied to the joint surface 4H of the leg member and the joint surface 7H of the insert member, respectively, and the three leg members 2H are adhesively joined to the insert member 7H (step S27). EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. Thereby, the three leg members 2H are electromagnetically coupled without being insulated from each other.

  In the joining and assembling step S27, the mutual interval between the pair of insert members 6H is positioned with high accuracy, and the three leg members 2H are positioned with high accuracy with respect to the pair of insert members 6H. It is made to contact | adhere so that a clearance gap may not arise between the joining surfaces 7H of an insert member. A dedicated jig (not shown) can be used for positioning at the time of joining. As a result, as shown in FIG. 18A, six joint portions 4H-7H are formed which are joined substantially without gaps. Since these joint portions 4H-7H are substantially free of gaps, the three leg members 2H and the two insert members 6H are electromagnetically closely coupled to each other. For this reason, when the three coil windings 8 are energized, the excitation inductances generated in the respective phases are equalized, and a low-loss and high-efficiency inductor 20H is obtained.

  Further, the insulating tape 19 is wound around the outer periphery of the inductor 20H, and the constituent members of the inductor are firmly fixed by taping (step S28).

  In this embodiment, the conductor member is wound around the leg member and then the leg member is joined to the insert member. However, the conductor member may be wound around the leg member of the core after joining the leg member and the insert member.

[Example 10]
As shown in FIG. 18B, the inductor 20I (magnetic core 10I) of Example 10 has a T-shape when viewed from the Z-axis direction and is viewed from the Y-axis direction, as in Example 9 described above. It forms a lattice shape and forms a ring shape when viewed from the X-axis direction. However, in the inductor 20I (magnetic core 10I) of the tenth embodiment, there is no insert member, and the three leg members 2I are directly joined to each other. That is, in the magnetic core 10I of the present embodiment, the end surfaces 4I of the two leg members 2I out of the three are butted and joined, and the end surface 4I of the remaining one leg member 2I is connected to the side surface of the two leg members 2I. Joined to 4S. As a result of butt joining the two leg members 2I, joints 4I-4I are formed. Further, as a result of side-joining the remaining one leg member 2I and the two leg members 2I, joined portions 4I-4S-4S are formed. None of these joint portions 4I-4I and 4I-4S-4S has substantially any gap, and the three leg members 2I are tightly joined to each other.

[Example 11]
As shown in FIG. 18 (c), the inductor 20J (magnetic core 10J) of the eleventh embodiment has a T-shape when viewed from the Z-axis direction as in the above-described ninth and tenth embodiments. A lattice shape is formed when viewed from the side, and a ring shape is formed when viewed from the X-axis direction. However, in the inductor 20J (magnetic core 10J) of the eleventh embodiment, the two leg members 2J and 9 are directly joined without using an insert member. That is, in the magnetic core 10I of the present embodiment, the end surface 4J of the leg member 2J is joined to the side surface 9S of the both leg members 9.

  The leg member 2J is formed in a U-shape when viewed from the side, and has one leg portion. A conductive wire is wound around one leg portion of the leg member 2J, and one coil winding 8 is formed. On the other hand, both the leg members 9 are formed in an annular shape or a ring shape and have two leg portions. Conductive wires are wound around the two leg portions of the both leg members 9 so that two coil windings 8 are formed.

  As a result of joining the leg member 2J and the both leg members 9, two joint portions 4J-9S are formed. None of these joints 4J-9S has a substantial gap, and the leg member 2J and both leg members 9 are tightly joined to each other.

  Next, with reference to FIG. 20, the magnetic core and inductor of Example 12 and the manufacturing method 5 for manufacturing them will be described. Note that the description of the parts of the twelfth embodiment overlapping with the ninth embodiment will be omitted.

[Example 12]
The magnetic core 10K and the inductor 20K according to the twelfth embodiment are substantially the same as those of the ninth embodiment except that the three leg members 2K are wound cores.

The leg member 2K is formed in a U shape when viewed from the side. The leg member 2K has a straight winding portion 3a at the center portion and end portions 3b on both sides thereof. The winding portion 3a is a main part of the leg member 2K around which the conducting wire is wound, and has a rectangular cross section with a uniform cross-sectional area S _A (= S _B , S _C ). A wound iron core made of a 3% Si-containing silicon steel strip was used as a material for the leg member 2K. Bonding surfaces 4K are formed at both ends of the winding portion 3a. The joining surface 4K is machined to be a flat surface.

  The insert member 6K is a dust core having substantially the same structure as the insert member 6H of Example 9 described above. Permalloy A (78.5% Ni-Fe alloy) defined in JIS C 2531 (1999) is used as the magnetic powder material. Using. Bonding surfaces 7K are formed on the four side surfaces of the insert member 6K. The joining surface 7K is machined so as to be a flat surface.

  The surface roughness and flatness of the joint surfaces 4K and 7K are finished to such an extent that no gaps are substantially generated in the six joint portions 4K-7K after bonding.

An insulating resin liquid is applied to the surface of the leg member 2K (excluding the joint surface 4K) to insulate the leg member 2K. A conducting wire is wound around each of the winding portions 3a of the magnetic core coated with insulation. The number of turns N _A , N _B , N _C of the three coil windings 8 is the same.

  The leg member 2K and the insert member 6K are respectively positioned with a dedicated jig, an adhesive is applied to the joint surface 4K of the leg member and the joint surface 7K of the insert member, and both are adhesively joined. Alemco Bond 526N from Odec Co., Ltd. was used as the adhesive. In this way, an inductor 20K of Example 12 shown in FIG. 20 was obtained.

[Production Method 5]
A method for manufacturing the magnetic core and the inductor according to the twelfth embodiment will be described with reference to FIG.

  A wound core commercially available under the name of a three-phase cut core was prepared as the leg member 2K. The wound iron core is manufactured by winding a directional silicon steel strip, annealing the strain relief, bonding the bonding surface with an adhesive, cutting the shape into a desired shape, and polishing (step S21). In Example 12, such a wound iron core was used for the leg member 2K.

The leg member 2K has a straight winding portion 3a that does not curve and a non-winding portion 3b that has a flat joint surface 4K, and has a U-shape when viewed from the side. The surface of the leg member 2K (excluding the bonding surface 4K), at least the surface of the winding part 3a, is insulation-coated (step S25). A conductive wire is directly wound around each of the winding portions 3a coated with insulation to produce three coil windings 8 (step S26). The number of turns N _A , N _B , N _C of the three coil windings 8 is the same.

  Next, the joining assembly of the three leg members 2K and the two insert members 6K will be described. The leg member 2K is covered with insulation except for the joint surface 4K, and a coil winding 8 is wound around the winding portion 3a. Adhesive is applied to the joint surface 4K of the leg member and the joint surface 7K of the insert member, respectively, and the three leg members 2K are adhesively joined to the insert member 7K, respectively (step S27). Alemco Bond 526N from Odec Co., Ltd. was used as the adhesive.

  In the joining and assembling step S27, the leg members are brought into close contact with each other so that no gap is generated between the joint surface 4K of the leg member and the joint surface 7K of the insert member. A dedicated jig (not shown) can be used for positioning at the time of joining. As a result, six joint portions 4K-7K joined substantially without gaps are formed. Since these joint portions 4K-7K have substantially no gap, the three leg members 2K and the two insert members 6K are electromagnetically closely coupled to each other. For this reason, when the three coil windings 8 are energized, the excitation inductance generated in each phase is equalized, and a low-loss and high-efficiency inductor 20K is obtained.

  Next, with reference to FIG. 21, the magnetic core and inductor of Example 13 and the manufacturing method 6 for manufacturing them will be described.

[Example 13]
As shown in FIG. 21, the inductor 20 </ b> L of the thirteenth embodiment includes three leg members 2 </ b> L, a pair of insert members 6 </ b> L, and three coil bobbins 18. The leg member 2L is composed of a straight round bar (cylindrical) powder magnetic core, and is attached between the pair of insert members 6L at equal intervals and in parallel. One coil bobbin 18 is attached to each leg member 2L.

  The coil bobbin 18 is obtained by winding a conductor 8 around a bobbin 17 made of an insulating resin such as polyethylene terephthalate (PET), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), or polyamide (PA). The leg member 2L is inserted through the hollow shaft of the coil bobbin 18, and the coil bobbin 18 is held by the leg member 2L.

  The pair of insert members 6 </ b> L is formed of a three-leaf-shaped powder magnetic core, and is spaced apart from each other so that the center passes through the central axis 30. The end surface of the leg member 2L is joined to each of the three leaves of the insert member 6L.

  When the three leg members 2L and the pair of insert members 6L are joined together, the magnetic core 10L of the present embodiment is obtained. Further, when the three coil bobbins 18 are respectively attached to the three leg members 2L of the magnetic core 10L, the inductor 20L of the present embodiment is obtained.

The size of each part of the inductor 20L of Example 13 is listed. The length of the leg is 25 mm, the diameter of the leg is 10 mm, the outer diameter of the coil bobbin is 11 mm, the length of the coil bobbin is 18 mm, the length of the winding part is 16 mm, and the cross-sectional area S _A (= S _B , S _C ) is 78.6 mm ² , the total area A _AS of the joint is 471.3 mm ² , the maximum diameter of the insert member is 30 mm, and the thickness of the insert member is 10 mm.

[Production Method 6]
As shown in FIG. 21, the magnetic powder for producing the leg member 2L of Example 13 is prepared (step S31-1). Various materials shown in Table 3 can be used as the magnetic powder. In this embodiment, an Fe—Si based alloy containing 3 to 8% Si was used as the magnetic powder material of the leg member 2L. A molding aid is mixed with the magnetic powder (step S32-1). Various materials shown in Table 2 can be used as molding aids. In this example, PVA and water glass were used as the molding aid for the leg member 2L.

  A mold having a cylindrical cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed at a predetermined pressure and room temperature (step S33-1). A straight round bar-shaped press-molded product is taken out from the mold, and both end portions of the press-molded product are each end-face ground. Thereby, the joining surface 4L of desired surface roughness is obtained in the both ends of a press molded product.

  The press-formed product was placed in a heat treatment furnace and heat-treated under conditions of 100 to 500 ° C. × 2 to 5 hours (Step S34-1). Thereby, the leg member 2L having a high magnetic permeability is obtained.

  Magnetic powder for preparing the insert member 6L is prepared (step S31-2). Various materials having no magnetic anisotropy shown in Table 3 can be used as the magnetic powder. In this example, Permalloy A (78.5% Ni-Fe alloy) defined in JIS C 2531 (1999) was used as the magnetic powder material of the insert member 6L. A molding aid is mixed with the magnetic powder (step S32-2). As the molding aid, various materials shown in Table 2 can be used. In this example, methylcellulose and water glass were used as molding aids for the insert member 6L.

  A mold having a three-leaf plate-like cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed under a predetermined pressure and room temperature (step S33-2).

  A three-leaf plate-shaped press-molded product is taken out from the mold, and the main surface of each press-molded product is mechanically ground. Thereby, the joining surface 7L of the desired surface roughness is obtained in the press-formed product. The press-molded product is placed in a heat treatment furnace and heat treated under conditions of 500 to 1000 ° C. × 2 to 5 hours (step S34-2). After the insert member 6L is taken out from the heat treatment furnace and the temperature is lowered to near room temperature, the surface of the insert member 6L (excluding the joining surface 7L) is insulation-coated (step S35-2).

  Next, the joining assembly of the three leg members 2L, the pair of insert members 6L, and the three coil bobbins 18 will be described.

  The leg member 2L and the insert member 6L are relatively aligned with a dedicated jig, an adhesive is applied to one joining surface 4L of the leg member 2L, and the one joining surface 4L of the leg member 2L is joined to the joining surface of the insert member 6L. Adhere to 7L (step S35-1). In aligning the members 2L and 6L, it is important that the leg member 2L is attached to the insert member 6L at a right angle.

A conductive wire is wound around the bobbin 17 made of an insulating resin to produce a total of three coil bobbins 18 (step S36). The number of windings N _A , N _B , and N _C for the three coil bobbins 18 is the same.

  Next, each leg member 2L on the insert member 6L is inserted through the hollow shaft of the coil bobbin 18, and the three coil bobbins 18 are respectively attached to the three leg members 2L (step S37).

  When the coil bobbin 18 is attached to the leg member 2 </ b> L, the other bonding surface 4 </ b> L that is not bonded is slightly protruded from the flange end surface of the coil bobbin 18. An adhesive is applied to the other joining surface 4L of the protruding leg member, and the other joining surface 4L of the leg member is adhered to the joining surface 7L of the other insert member (step S38). EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. As a result, an inductor assembly 20L in which the three members of the leg member 2L, the insert member 6L, and the coil bobbin 18 are joined and assembled is obtained.

  Further, the insulating tape 19 is wound around the outer periphery of the inductor 20L, and the constituent members of the inductor are firmly fixed by taping (step S39).

  In the joining and assembling step S38 of the present embodiment, the leg members are brought into close contact with each other so that no gap is generated between the joining surface 4L of the leg member and the joining surface 7L of the insert member. A dedicated jig (not shown) can be used for positioning at the time of joining. As a result, six joint portions 4L-7L joined substantially without gaps are formed. Since these joint portions 4L-7L are substantially free of gaps, the three leg members 2L and the pair of insert members 6L are electromagnetically closely coupled to each other. For this reason, when the three coil windings 8 are energized, the excitation inductance generated in each phase becomes equal. As a result, a low-loss and high-efficiency inductor 20H can be obtained.

  The inductor manufacturing method using the coil bobbin 18 is not limited to the present embodiment, and can be applied to other embodiments.

  In the present embodiment, the shape of the insert member is a three-leaf plate, but it may be a disc or a column.

  Next, with reference to FIG. 22, the magnetic core and inductor of Example 14 and the manufacturing method 7 for manufacturing them will be described.

[Example 14]
The description of the same parts as in the thirteenth embodiment will be omitted. The magnetic core 10M and the inductor 20M of the fourteenth embodiment are substantially the same as those of the thirteenth embodiment except that a hole for fitting a leg member is formed in the insert member.

  In the fourteenth embodiment, the leg member 2M and the coil bobbin 18 are substantially the same as in the thirteenth embodiment, but the insert member 6M is different from the thirteenth embodiment. That is, in the insert member 6M of the present embodiment, a three-leaf plate shape similar to the insert member is formed, but a hole 61 is formed in each leaf of the three-leaf. That is, the end portions of the leg members 2M are fitted into the holes 61 of the insert member 6M, respectively, and an adhesive is applied to the fitting portions to join both the members 2M and 6M. In this joining structure, the end part outer peripheral surface 4M of the leg member and the peripheral wall surface of the hole 61 of the insert member are joined to form a joined part 4M-61 having substantially no gap.

  When the three leg members 2M and the pair of insert members 6M are joined together, the magnetic core 10M of the present embodiment is obtained. Further, when the three coil bobbins 18 are respectively attached to the three leg members 2M of the magnetic core 10M, the inductor 20M of this embodiment is obtained.

[Production Method 7]
The leg member manufacturing steps S41-1 to S45-1 of the manufacturing method 7 are substantially the same as the steps S31-1 to S35-1 of the method 6. The coil bobbin manufacturing steps S46 to S47 are substantially the same as the steps S36 to S37 of the method 6.

  Magnetic powder for preparing the insert member 6M is prepared (step S41-2). Various materials having no magnetic anisotropy shown in Table 3 can be used as the magnetic powder. In this example, Permalloy A (78.5% Ni-Fe alloy) defined in JIS C 2531 (1999) was used as the magnetic powder material of the insert member 6M. A molding aid is mixed with the magnetic powder (step S42-2). As the molding aid, various materials shown in Table 2 can be used. In this example, methylcellulose and water glass were used as molding aids for the insert member 6M.

  A mold having a perforated three-leaf plate-shaped cavity is prepared, mixed powder is supplied to the mold cavity, and press molding is performed at a predetermined pressure and room temperature (step S43-2). A punched three-leaf plate shaped press-molded product is taken out from the mold, and the peripheral walls of the three holes of the press-molded product are each mechanically ground. Thereby, the hole 61 having the joining surface 7M having a desired surface roughness is obtained.

  The press-molded product is placed in a heat treatment furnace and heat treated under conditions of 500 to 1000 ° C. × 2 to 5 hours (step S44-2). After the insert member 6M is taken out from the heat treatment furnace and the temperature is lowered to near room temperature, the surface of the insert member 6M (excluding the joining surface 7M) is insulation-coated (step S45-2).

  Next, the joining assembly of the three leg members 2M, the pair of insert members 6M, and the three coil bobbins 18 will be described.

  Adhesives are respectively applied to the wall surface of the hole 61 of one insert member and the outer peripheral surface 4M of the end of the leg member, and the end of the leg member 2M is fitted into the hole 61. As shown in FIG. Is joined to one insert member 6M.

  Next, each leg member 2M on the insert member 6M is inserted through the hollow shaft of the coil bobbin 18, and the three coil bobbins 18 are respectively attached to the three leg members 2M (step S47).

  When the coil bobbin 18 is attached to the leg member 2 </ b> M, the other bonding surface 4 </ b> M that is not bonded protrudes from the flange end surface of the coil bobbin 18. The adhesive is applied to the outer peripheral surface 4M of the other end of the protruding leg member, and the adhesive is also applied to the wall surface of the hole 61 of the other insert member 6M, and the end of the leg member 2M is fitted into the hole 61. 22, the three leg members 2M are joined to the other insert member 6M (step S48). EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. As a result, an inductor assembly 20M is obtained in which the three members of the leg member 2M / insert member 6M / coil bobbin 18 are joined and assembled.

  Further, the insulating tape 19 is wound around the outer periphery of the inductor 20M, and the constituent members of the inductor are firmly fixed by taping (step S49).

  In the joining and assembling step S48 of this embodiment, the leg member 2M and the insert member 6M can be accurately positioned without using a dedicated positioning jig.

(Third embodiment)
Next, the magnetic core (two-piece bonded core) and inductor according to the third embodiment and their manufacturing methods will be described. As shown in FIGS. 23, 24, 25, and 18 (c), the magnetic core and the inductor of the third embodiment are produced by joining two pieces, respectively.

[Example 15]
A magnetic core and an inductor of Example 15 according to the third embodiment will be described with reference to FIG.

  The magnetic core 10N of Example 15 is formed by joining two half-tripod members 2N as shown in FIG. The half tripod member 2N is a tripod member having three legs having a half length which becomes a leg portion after joining and assembly. That is, the half tripod member 2N has a shape like a tripod chair or a tripod stand, and includes three leg portions and three branch portions to which the base portions of the three leg portions are connected together. The trifurcation is a flat plate parallel to the XY plane. Three leg portions extend in the Z-axis direction orthogonal to the three branch portions. The three legs have half the length of the winding portion 3a around which the conducting wire is wound, are formed in a rectangular shape having the same cross-sectional area, and flat joint surfaces 4N are formed at the ends.

  The three joint surfaces 4N are butted together and bonded, and the two half tripod members 2N are joined together, whereby the magnetic core 10N of the present embodiment is obtained.

The size of each part of the magnetic core 10N of Example 15 is listed. The leg length is 40 mm, the leg width is 10 mm, the leg thickness is 5 mm, the winding length is 30 mm, the maximum diameter of the non-winding part (three-branch part) is 10 mm, and the leg part is broken. The area S _A (= S _B , S _C ) is 50 mm ² , and the total area A _AS of the joint is 150 mm ² .

[Production Method 8]
Magnetic powder for preparing the half tripod member 2N is prepared (step S51). Various materials shown in Table 4 can be used as the magnetic powder. In this embodiment, an Fe—Si alloy containing 3 to 8% Si was used as the magnetic powder material of the leg member 2N. A molding aid is mixed with the magnetic powder (step S52). Various materials shown in Table 2 can be used as molding aids. In this example, PVA and water glass were used as molding aids for the leg member 2N.

  A mold having a tripod stand-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed under a predetermined pressure and room temperature (step S53). Thereby, a half tripod press-formed product 2N shown in FIG. 23 is obtained. The half-tripod press-molded product 2N has a three-branch portion and three legs. 4 N of joining surfaces are each formed in the edge part of each leg part. The joint surface 4N is mechanically ground and finished to an arithmetic average roughness Ra of 5 μm or less.

  The press-formed product is placed in a heat treatment furnace and heat treated under conditions of 100 to 1000 ° C. × 2 to 5 hours (step S54). In this case, it is desirable that the iron powder and the amorphous powder be heat-treated at 100 to 500 ° C, and the other magnetic materials should be heat-treated at 500 to 1000 ° C. After taking out the magnetic core 2N from the inside of the heat treatment furnace and lowering the temperature to near room temperature, the surface of the magnetic core 2N to be a leg member (excluding the bonding surface 4N) is insulatively coated (step S55).

  Two half-tripod press-molded products 2N are faced to each other and aligned relative to each other, the three bonding surfaces 4N are faced to each other, an adhesive is applied to each bonding surface 4N, and the bonding surfaces 4N are butt-bonded to each other. Joining (step S56). EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. Thereby, the magnetic core 10N of the present embodiment is obtained. The magnetic core 10N has three joint portions 4N-4N firmly bonded with an adhesive. Since these joints 4N-4N are substantially free of gaps, the two half-tripod press-formed products 2N are in close electromagnetic contact with each other.

Next, a conductive wire is directly wound around the insulated winding portion of the magnetic core 10N to form three coil windings 8 (step S57). Thereby, the inductor 20N of the present embodiment is obtained. Further, the insulating tape 19 is wound around the outer periphery of the inductor 20N, and the constituent members of the inductor are firmly fixed by taping (step S58).

[Example 16]
The inductor 20P of Example 16 is formed by joining two half tripod members 2P as shown in FIG. The two half tripod members 2P are shaped like a tripod chair or a tripod stand, and each has three branches and three branch portions to which the bases of the three legs are connected together. The trifurcation is a flat plate parallel to the XY plane. Three leg portions extend in the Z-axis direction orthogonal to the three branch portions. The three leg portions are half the length of the winding portion 3a around which the conducting wire is wound, are formed in a cylindrical shape having the same cross-sectional area, and flat joint surfaces 4P are formed at the ends.

  These three joint surfaces 4P are abutted and bonded together, and the two half tripod members 2P are joined to each other, whereby the magnetic core 10P of the present embodiment is obtained.

The size of each part of the magnetic core 10P of Example 16 is listed. The length of the leg (core height) is 70 mm, the diameter of the leg is 10 mm, the length of the winding part is 25 mm, the maximum diameter of the non-winding part (three-branch part) is 10 mm, and the cross-sectional area S of the leg part _{a (= S B, S C} ) is 78.6mm ^2, the total area of the joint portion a _aS; is 235.8mm ^2.

[Production Method 9]
As shown in FIG. 24, magnetic powder for preparing the half tripod member 2P of Example 16 is prepared (step S61). Various materials shown in Table 4 can be used as the magnetic powder. In this example, an Fe—Si alloy containing 3 to 8% Si was used as the magnetic powder material of the leg member 2P. A molding aid is mixed with the magnetic powder (step S62). Various materials shown in Table 2 can be used as molding aids. In this example, PVA and water glass were used as molding aids for the leg member 2P.

  A mold having a tripod stand-shaped cavity is prepared, mixed powder is supplied to the cavity of the mold, and press molding is performed at a predetermined pressure and room temperature (step S63). In this embodiment, the press molding is performed in a cold manner. However, as another method, it is possible to perform the press molding in a warm or hot state in which preheating is performed. Thereby, a half tripod press-formed product 2P shown in FIG. 24 is obtained. The half tripod press-molded product 2P has a three-branch portion and three legs. A joint surface 4P is formed at the end of each leg. The joint surface 4P is mechanically ground and finished to a surface roughness of 5 μm or less with an arithmetic average roughness Ra.

  The press-formed product was placed in a heat treatment furnace and heat-treated under conditions of 100 to 500 ° C. × 2 to 5 hours (Step S64). After taking out the half tripod press-formed product 2P from the heat treatment furnace and lowering the temperature to near room temperature, the surface of the magnetic core 2P (excluding the bonding surface 4P) serving as the leg member is subjected to insulation coating (step S65).

A conductive wire is wound around the insulating bobbin 17 to produce a total of three coil bobbins 18 (step S66). The number of windings N _A , N _B , and N _C for the three coil bobbins 18 is the same.

  Next, the leg portion of one half-tripod press-formed product 2P is inserted through the hollow shaft of the coil bobbin 18, whereby the three coil bobbins 18 are respectively attached to the three leg members 2L (step S67).

  The two half-tripod press-formed products 2P are faced to each other and aligned relative to each other, the three joint surfaces 4P are faced to each other, an adhesive is applied to each joint surface 4P, and the joint surfaces 4P are butt-bonded to each other. Joining (step S68). EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. Thereby, the inductor 20P of the present embodiment is obtained. The magnetic core 10P of the inductor 20P has three joint portions 4P-4P firmly bonded with an adhesive. Since these joint portions 4P-4P have substantially no gap, the two half tripod press-formed products 2P are closely electromagnetically joined to each other. Further, the insulating tape 19 is wound around the outer periphery of the inductor 20P, and the constituent members of the inductor are firmly fixed by taping (step S69).

[Example 17]
The magnetic core 10Q of Example 17 is formed by joining two half tripod members 2Q as shown in FIGS. 26 (a) and 26 (b). The two half tripod members 2Q have a curved C-shape, and each has three leg portions and three branch portions to which the base portions of the three leg portions are connected together. The three branches are curved plate shapes. Three leg portions extend from the three branch portions. The three legs have half the length of the winding portion 3a around which the conducting wire is wound, are formed in a curved plate shape having the same rectangular cross section, and a flat joining surface 4Q is formed at each end. .

  The surface of the half tripod member 2Q (excluding the joining surface 4Q) is insulation-coated, the three joining surfaces 4Q are abutted and bonded together, and the two half tripod members 2Q are joined together. EW2030 manufactured by 3M Japan Ltd. was used as an adhesive. Thereby, the magnetic core 10Q of the present embodiment is obtained. The magnetic core 10Q has three joint portions 4Q-4Q firmly bonded with an adhesive. Since these joint portions 4Q-4Q have substantially no gap, the two half tripod press-formed products 2Q are closely electromagnetically joined to each other.

A conductor is wound around each of the three legs of the magnetic core 10Q to obtain the inductor 20Q of the present embodiment shown in FIG. The number of windings N _A , N _B , and N _C for the three legs is the same. Thereby, the inductor 20Q of the present embodiment is obtained.

  The three-phase tripod magnetic core of the present invention can be used as an inductor core used as an AC filter in a three-phase PWM inverter circuit of an uninterruptible power supply (UPS). Furthermore, the three-phase tripod magnetic core of the present invention can be used not only as an inductor core but also as a transformer core. In addition, the three-phase tripod inductor of the present invention can be used as a filter component for various power device circuits, and is particularly used as an AC filter incorporated in a three-phase PWM inverter circuit of an uninterruptible power supply (UPS).

2,2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H, 2I, 2J, 2K, 2L, 2M ... Leg member (single leg member that becomes the leg after joining assembly),
2M, 2N, 2P, 2Q… Half leg member (tripod member with half length that becomes the leg after joining assembly),
3a ... Winding part (main part of the leg part around which the conducting wire is wound),
3b ... end (a part of the leg where the joint is formed),
4-4, 4A-4A, 4A-4B, 4C-4C, 4A-4C, 4D-7, 4E-7, 4F-7F, 4G-7G, 4H-7H, 4I-4I, 4I-4S-4S, 4J-9S, 4K-7K, 4L-7L, 4M-7M, 4N-4N, 4P-4P, 4Q-4Q ... Junction,
4,4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4I, 4J, 4K, 4L, 4M, 4N, 4P, 4Q ... Joint surface of leg members,
5… Insulation case cover,
6,6F, 6G, 6H, 6K, 6L, 6M ... insert member, 7,7F, 7G, 7H, 7K, 7L ... joint surface of insert member, 8 ... coil winding, 9 ... both legs (two windings) An annular core having a portion),
10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K, 10L, 10M, 10N, 10P, 10Q ... Core (core),
16: Non-interference space (space where three coil windings do not interfere with each other),
17 ... insulating bobbin, 18 ... coil bobbin, 19 ... fixing tape,
20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I, 20J, 20K, 20L, 20M, 20N, 20P ... inductor, 30 ... central axis.

Claims (20)

Three legs forming a non-interference space that is composed of a leg member including a winding portion around which a conducting wire is wound, and in which the coil windings to be formed in the winding portion are spaced apart without interfering with each other Legs,
One leg member constituting the leg portion is directly joined to each other where it meets the other leg member, or indirectly joined via another member so that the three leg portions are electromagnetically connected to each other. Joined joints,
A three-phase tripod magnetic core characterized by comprising:   The three legs are arranged around a central axis so as to surround the central axis, and each of the winding parts bulge outwardly so as to be separated from the central axis. core.   The magnetic core according to claim 2, wherein the winding portion has a straight shape.   The magnetic core according to claim 2, wherein the winding portion has a curved shape.   The magnetic core according to claim 1, wherein the three legs are arranged symmetrically about the central axis.   The magnetic core according to claim 1, wherein the three legs are disposed asymmetrically around a central axis.   The magnetic core according to claim 1, wherein the cross-sectional areas of the three legs are substantially the same.   The magnetic core according to claim 1, wherein the three legs have substantially the same shape.   The magnetic core according to claim 1, wherein at least one of the three legs has a different shape.   The magnetic core according to claim 1, wherein the joint portion is joined substantially without a gap.   The magnetic core according to claim 10, wherein the joint portion is formed by bonding smooth surfaces with an adhesive.   The magnetic core according to claim 1, wherein each of the magnetic cores is constituted by three single leg members including one winding portion. Three single leg members each including a single winding portion and having a first joint surface formed at each end of the winding portion;
Each of which is formed in a polygonal prismatic shape, is inserted between the three single leg members, and has three second joint surfaces to be joined to each of the first joint surfaces. A pair of insert members made of a magnetic material having no directivity,
The said joint part is formed by joining the said 1st joining surface and the said 2nd joining surface, It comprised by the said 3 single leg member and the said pair of insert member, It is characterized by the above-mentioned. The magnetic core according to 1.   The magnetic core according to claim 13, wherein the insert member is made of a magnetic material different from that of the single leg member. A first branching surface having a three-branch portion, a tripod portion branched from the three-branch portion and having a leg length that is half the length of the leg portion, and a first joint surface formed at each end of the tripod portion; 1 half leg member;
A branch part, a tripod part branched from the three branch part and having a leg length half the length of the leg part, and an end part of the tripod part to be joined to the first joining surface, respectively A second half leg member having a formed second joining surface;
Comprising
The joining portion is formed by joining the first joining surface and the second joining surface, and is configured by the first half leg member and the second half leg member. The magnetic core according to claim 1.   2. The magnetic core according to claim 1, wherein the three legs are made of a powder magnetic core formed by press-molding magnetic powder.   The magnetic core according to claim 1, wherein the three leg portions are made of a wound iron core. Three legs forming a non-interference space that is composed of a leg member including a winding portion around which a conducting wire is wound, and in which the coil windings to be formed in the winding portion are spaced apart without interfering with each other Legs,
One leg member constituting the leg portion is directly joined to each other where it meets the other leg member, or indirectly joined via another member so that the three leg portions are electromagnetically connected to each other. Joined joints,
Three coil windings disposed in the non-interference space and wound directly or indirectly around the three winding portions,
A three-phase tripod inductor characterized by comprising:   The inductor according to claim 18, wherein the coil winding is formed by winding a conducting wire directly around the winding portion covered with insulation.   The inductor according to claim 18, wherein the coil winding is formed by winding a conducting wire around an insulating bobbin, and the insulating bobbin around which the conducting wire is wound is attached to the winding portion.

Images