WO2017047740A1

WO2017047740A1 - Magnetic element

Info

Publication number: WO2017047740A1
Application number: PCT/JP2016/077412
Authority: WO
Inventors: 香代堺
Original assignee: Ntn株式会社
Priority date: 2015-09-17
Filing date: 2016-09-16
Publication date: 2017-03-23

Abstract

To provide a magnetic element in which the number of components and the amount of copper wire used can be reduced and the working man-hours can be lowered. The magnetic element 1 is provided with a coil assembly 4, in which a coil 3 is wound around the outer periphery of a core 2 comprising a compression-molded magnetic material, and an outer periphery core 5 covering the outer periphery of the coil assembly 4. The outer periphery core 5 comprises an injection-molded magnetic material, and has, on the inner peripheral surface of the outer periphery core, an opening part 5a into which the coil can be inserted, and a pair of grooves 5b into which both axial ends of the core 2 can be inserted as a fixing means for fixing the coil assembly 4 in the outer periphery core.

Description

Magnetic element

The present invention relates to a magnetic element in which a coil assembly is arranged around a magnetic body, and relates to a magnetic element used in an electric device or an electronic device as an inductor, a transformer, an antenna (bar antenna), a choke coil, a filter, a sensor, or the like. In particular, the present invention relates to a magnetic element that can be mounted on a substrate.

In recent years, as electric and electronic devices are becoming higher in frequency and larger in current, the magnetic element is required to have the same response. However, the material properties of the mainstream ferrite material as a magnetic material have reached their limits. New magnetic materials are being sought. For example, ferrite materials are being replaced by compression molded magnetic materials such as sendust and amorphous, amorphous foil strips, and the like. However, the compression-molded magnetic material has poor moldability and low mechanical strength after firing. In addition, the amorphous foil strip is expensive to manufacture due to winding, cutting, and gap formation. For this reason, the practical application of these magnetic materials has been delayed.

Patent Document 1 has been proposed as a method for producing a small and inexpensive magnetic core component having a variety of shapes and characteristics using magnetic powder having poor formability. In Patent Document 1, magnetic powder contained in a resin composition used for injection molding is covered with an insulating material, and either a compression-molded magnetic body or a compacted magnet molded body is insert-molded into the resin composition, and compression molding is performed. There has been proposed a method of manufacturing a core part having a predetermined magnetic property, which contains a binder having a melting point lower than the injection molding temperature, by a magnetic body or a compacted magnet molded body (see Patent Document 1). ).

As a magnetic element that can reduce the number of parts and manufacturing man-hours, reduce the product height, improve reliability, configure part of the magnetic path of the magnetic core structure with the insulating base of the composite magnetic molded body, 2. Description of the Related Art A magnetic element having a configuration in which a coil terminal is directly pulled out to the base side as an external terminal is known (see Patent Document 2).

A conventional EEP type magnetic element is shown in FIG. FIG. 17A is a perspective view showing an assembly method, and FIG. 17B is a completed perspective view. The magnetic element 41 is assembled by inserting the core core 42a and the outer core 42 integrally formed into two parts, with the core core 42a facing the core core 42a. At the time of assembly, the two parts need to be positioned in the radial direction and the axial direction. In particular, in the case of resin sealing, since it is necessary to make positioning accurate, the number of work steps increases. Further, since it is necessary to seal the resin with the coil 43 built therein, it takes time to fill the sealing resin, and voids are easily generated.
In the case of a hybrid magnetic element in which the outer core 42 and the core 42a are combined with different materials, the number of parts increases because two coil outer cores and one or more coil inner cores are combined. As described above, the conventional EEP type magnetic element is desired to be improved in terms of production and quality.

Japanese Patent No. 4766609 JP 2000-331841 A

The magnetic element of a closed magnetic circuit has a small air gap in the magnetic path, such as a pot-shaped core, an EER core, an EEP core, a core combining a drum core and an outer peripheral core, etc. Therefore, magnetic flux leakage is small, and the physique can be made smaller than a magnetic element having an open magnetic path. However, the above-mentioned pot-type core, EER-type core, EEP-type core, etc. are used when the magnetic element is assembled or when the gap between the coil and the outer core is filled with resin, the core core of the coil assembly in which the coil is arranged is used. Since it is necessary to position in the radial direction and axial direction of the coil, there is a problem that the number of work steps increases. In addition, a core that combines a drum-shaped core, a coil, and an outer peripheral core has a large coil wire radius when the magnet wire has a large cross-sectional area. There is a problem that the degree of freedom becomes lower and the magnetic element size becomes larger.

The present invention has been made to cope with such problems, and has an object to provide a magnetic element that can reduce the number of work steps and reduce the number of parts and the amount of metal having excellent conductivity such as copper wire.

The magnetic element of the present invention includes a coil assembly in which a coil is disposed on the outer periphery of a core core, and an outer peripheral core that covers the outer periphery of the coil assembly. The outer peripheral core includes an opening through which the coil assembly can be inserted, and the coil assembly. It has the fixing means fixed in an outer periphery core, It is characterized by the above-mentioned. In particular, the core is a compression molded magnetic body, and the outer core is an injection molded magnetic body.

In the case of a magnetic element having a core core in which the core core is provided with a pair of flange portions at both axial ends of the columnar core core, the fixing means closely contacts the outer peripheral shape of the pair of flange portions with the inner peripheral surface of the outer core. By adopting such a shape, the coil assembly is fixed in the outer core.

In the case where the core core is a magnetic element having a columnar core, the fixing means includes (1) a pair of grooves provided inside the outer core and into which both axial ends of the columnar core can be inserted. (2) The coil assembly is fixed in the outer core by providing any one means of providing the outer core with at least one through hole for inserting the core core.

The core core is a magnetic element having a columnar core, and the columnar core is formed on at least one of an axial intermediate portion, an axial end surface portion, and a circumferential portion in the vicinity of the axial end surface of the columnar core core. A spacer to be fitted is provided.

Further, the outer peripheral core in which the coil assembly is fixed is characterized in that at least one outer peripheral surface of the outer peripheral core has a shape that can be fixed to a substrate of an electronic device.

Since the magnetic element of the present invention has an opening through which the coil assembly can be inserted and a fixing means for fixing the coil assembly in the outer core, workability when fixing the coil assembly in the outer core is improved. Further, in the case of a hybrid magnetic element in which a magnetic body serving as a core core is a compression molded magnetic body having excellent thermal conductivity and a magnetic body serving as an outer core is an injection molded magnetic body, the core core and the outer core are divided. Thus, since the outer core is not divided into two, the number of parts can be reduced. In addition, since the spacer that can be fitted to the core core is provided, when the coil and the core are assembled into a coil assembly, the spacer is not required to be bonded, and the workability is improved. Since the presence or absence of the spacer can be visually confirmed after assembling the coil and the core, misassembly can be prevented. Furthermore, when fixing a magnetic element to the board | substrate of an electronic device, it becomes easy to employ | adopt optimal arrangement | positioning, such as making an opening part and a board | substrate oppose, and can reduce the usage amount and processing cost of a magnet wire used for a coil.

It is a perspective view of an EEP type magnetic element. FIG. 2 is an assembly process diagram of the EEP type magnetic element shown in FIG. 1. It is a perspective view which shows the other example of the EEP type | mold magnetic element shown in FIG. It is a perspective view of another EEP type magnetic element. FIG. 5 is an assembly process diagram of the EEP type magnetic element shown in FIG. 4. It is a perspective view of another EEP type magnetic element. FIG. 7 is an assembly process diagram of the EEP type magnetic element shown in FIG. 6. It is the perspective view and sectional drawing of an EEP type magnetic element with a spacer. FIG. 9 is an assembly process diagram of the EEP type magnetic element shown in FIG. 8. It is the perspective view and sectional drawing of another EEP type magnetic element with a spacer. FIG. 11 is an assembly process diagram of the EEP type magnetic element shown in FIG. 10. It is the perspective view and sectional drawing of another EEP type magnetic element with a spacer. FIG. 13 is an assembly process diagram of the EEP type magnetic element shown in FIG. 12. It is the perspective view and sectional drawing of another EEP type magnetic element with a spacer. FIG. 15 is an assembly process diagram of the EEP type magnetic element shown in FIG. 14. It is a figure which shows the example which uses a magnetic element as surface mounting components. It is a perspective view of the conventional EEP type magnetic element. It is a figure of an EEP type magnetic element with a spacer.

Magnetic elements using ferrite materials obtained by current mainstream compression molding methods with high frequency and large current in electrical and electronic equipment have excellent magnetic permeability and easy to obtain inductance value, but frequency characteristics and superimposed current characteristics Inferior to On the other hand, a magnetic element using an injection-molded magnetic material containing an amorphous material is excellent in frequency characteristics and superimposed current characteristics, but has a low magnetic permeability. Moreover, in addition to heat generation due to copper loss, heat generation due to iron loss cannot be ignored in the magnetic element for large current. The present invention relates to a hybrid magnetic element in which a magnetic body that is a core core that is a part that easily generates heat or a part that does not easily dissipate heat is a compression-molded magnetic body having excellent thermal conductivity, and a magnetic body that is an outer core is an injection-molded magnetic body. It is preferable that By adopting the structure of the present invention, the number of parts is reduced and the assembly workability is improved.

An example of the magnetic element of the present invention is shown in FIG. FIG. 1A is a perspective view of an EEP type magnetic element, and FIG. 1B is a cross-sectional view in the AA direction. The magnetic element 1 includes a coil assembly 4 in which a coil 3 is arranged on the outer periphery of a cylindrical core core 2 and an outer core 5 that covers the outer periphery of the coil assembly 4. A groove 5b is provided on the opening 5a side of the outer peripheral core 5, and the opposite back surface 5c is semicircular in plan view. The columnar core 2 is inserted perpendicular to the axis of the magnetic element 1, and the core 2 and the outer core 5 are magnetically integrated.

The assembly method of the magnetic element 1 is shown in FIG. 2 (a) to 2 (c) are assembly steps shown in perspective views. The magnetic component constituting the magnetic element 1 is composed of two components divided into a core core 2 and an outer peripheral core 5. The outer core 5 is provided with an opening 5a into which the coil assembly 4 can be inserted and a groove 5b for fixing the coil assembly 4 in the outer core 5 in the vertical direction of the opening. A cylindrical core 2 is inserted in the coil 3 wound in advance in the direction of the arrow (FIG. 2A). Both end portions 2a of the cylindrical core core 2 are inserted in the direction of the arrow along the upper and lower grooves 5b provided on the inner peripheral surface of the outer peripheral core 5. This groove 5b also serves as a positioning in the radial direction excluding the axial direction of the cylindrical core core 2 and the insertion direction (FIG. 2B). That is, the assembly 4 is fixed in the outer core 5 by being inserted along the groove 5b (FIG. 2C). Thus, in the present invention, since the cylindrical core core 2 is inserted from a direction perpendicular to the coil axis direction, positioning in the radial direction and the axial direction other than the insertion direction is unnecessary, and the assembly is simplified. Moreover, since it becomes the combination of the outer periphery core 5 and the cylindrical core core 2, the number of parts can be reduced. The core core 2 may have a polygonal shape other than the columnar shape as long as it is columnar.

In the case of resin sealing, the conventional EEP type core shown in FIG. 17 needs to be accurately positioned in the radial direction and the axial direction, but the magnetic element of the present invention does not need to be positioned in the radial direction or the axial direction. Improves. In addition, by pre-filling the sealing resin, the filling time can be shortened and voids can be reduced, resulting in a highly reliable magnetic element.

FIG. 3 shows another example of the EEP type magnetic element shown in FIG. The magnetic element 1a shown in FIG. 3A is the case where the opposite back surface 5c in FIG. 1 is a straight line, that is, the case where the outer core 5 is square in plan view, and the magnetic element 1b shown in FIG. Similarly, the back surface 5c is a polygon in plan view. Since the present invention does not require positioning of the core 2, the shape of the outer core 5 can be arbitrarily set according to the specifications of the magnetic element, the arrangement method, and the like. For example, by increasing the surface area of the outer peripheral surface other than the opening of the outer core 5, the heat dissipation can be improved and the temperature of the magnetic element can be lowered.

Another example of the EEP type magnetic element is shown in FIGS. FIG. 4 is a perspective view of the EEP type magnetic element, and FIG. 5 is an assembly process shown in the perspective view. The magnetic element 6 includes a coil assembly 9 in which a coil 8 having a magnet wire wound around an outer periphery of a cylindrical core core 7 having a pair of flange portions 7a provided at both ends in the axial direction, and an outer periphery of the coil assembly 9. The outer peripheral core 10 to cover is provided. The back surface 10b opposite to the opening 10a side of the outer peripheral core 10 is semicircular in plan view.

The magnetic component constituting the magnetic element 6 is composed of a core core 7 and an outer peripheral core 10 which are divided into drum-shaped cores. The outer peripheral core 10 is not provided with the groove shown in FIG. 1, and the outer peripheral shape of the flange portion 7a is in close contact with the inner peripheral surface 10c of the outer peripheral core, and the outer periphery of the flange portion 7a is in close contact with the inner peripheral surface 10c. A coil assembly 9 is fixed in the outer core 10. As in the case of the magnetic element 1 shown in FIG. 1, there may be a groove for inserting the outermost diameter portion of the drum core in the outer core 10.

The drum core 7 divided into two is inserted in the direction of the arrow in the axial direction of the coil 8 around which the magnet wire is wound (FIG. 5A). In addition, the coil 8 may wind a magnet wire directly around the drum-shaped core 7, and in this case, the drum-shaped core 7 may not be divided into two. The drum core 7 is inserted in the direction of the arrow so as to be in close contact with the inner peripheral surface 10c provided on the inner peripheral surface of the outer peripheral core 10 (FIG. 5B). That is, the coil assembly is fixed in the outer core 10 when the outer peripheral surface of the flange 7a is in close contact with the inner peripheral surface 10c of the outer core 10 (FIG. 5C).

In the case of a resin-sealed magnetic element, the shape shown in FIGS. 1, 3, 4 and 5 described above and the following FIGS. 8 and 10 are preferable. The sealing resin can be pre-filled before the coil insertion process at the time of assembly. Further, it is preferable that the outer diameter surface of the outer peripheral core other than the coil insertion opening has a large surface area as long as the magnetic characteristics are not deteriorated. By increasing the surface area, the temperature rise of the magnetic element can be suppressed.

Another example of the EEP type magnetic element is shown in FIGS. FIG. 6 is a perspective view of the EEP type magnetic element, and FIG. 7 is an assembly process shown in the perspective view. The magnetic element 11 includes a coil assembly 14 including a coil 13 around which a magnet wire is wound around an outer periphery of a cylindrical core core 12, and an outer core 15 that covers a substantially outer periphery of the coil assembly 14. The outer core 15 is provided with a through hole 15b in the outer core 15 into which the core 12 can be inserted. Two through holes 15b may be provided in the insertion direction of the core core 12, and one may be a through hole 15b and the other may be a non-through hole. By preventing one side from penetrating, it can be prevented from coming off on one side in the axial direction.
The coil 13 wound in advance is inserted through the opening 15a of the outer core 15 in the direction of the arrow (FIG. 7A), and the core core 12 is inserted through the through hole 15b provided in the end face of the outer core 15 in the direction of the arrow. (FIG. 7B). A coil assembly 14 composed of the coil 13 and the core core 12 is fixed in the outer core 15 (FIG. 7C). In addition, since the core 12 having excellent thermal conductivity exists on the surface of the outer core 15, the heat dissipation of the magnetic element 11 is improved.

FIG. 18 shows another example of the EEP type magnetic element. The EEP type magnetic element may have a gap for adjusting the magnetic characteristics of the inductor. FIG. 18 shows an example of a magnetic element in which a spacer is provided in the middle of the core core to provide a gap. 18 (a) and 18 (b) are perspective views showing an assembling method, FIG. 18 (c) is a completed perspective view, and FIG. 18 (d) is a cross-sectional view in the FF direction. The magnetic element 44 includes a coil assembly 47 in which a coil 46 is disposed on the outer periphery of a cylindrical core core 45, and an outer core 48 that covers the outer periphery of the coil assembly 47. A spacer 49 is provided in the middle of the columnar core 45. The magnetic element 44 is assembled by inserting the coil assembly 47 into the outer core 48.

An example of the magnetic element with a spacer of the present invention is shown in FIG. FIG. 8A is a perspective view of an EEP type magnetic element, and FIGS. 8B and 8C are cross-sectional views in the BB direction. The magnetic element 16 includes a coil assembly 19 in which a coil 18 is disposed on the outer periphery of a cylindrical core core 17 and an outer core 20 that covers the outer periphery of the coil assembly 19. A groove 20b is provided on the opening 20a side of the outer peripheral core 20, and the opposite back surface 20c is semicircular in plan view. The columnar core 17 is inserted from a direction perpendicular to the axis of the magnetic element 16, and the core 17 and the outer core 20 are magnetically integrated. The cylindrical core 17 has a spacer 21 in the middle, and the spacer 21 has a core 17 and a fitting portion 21a. The fitting portion 21a may be provided at the circumferential portion of the core core 17 as shown in FIG. 8B, and at the axial center portion of the core core 17 as shown in FIG. 8C. It may be provided. A fitting portion 17a of the core core 17 is provided in a corresponding portion to which the fitting portion 21a of the spacer 21 is fitted. If either one of the fitting portion 21a and the fitting portion 17a is convex, the other is concave, and both can be integrated by fitting each other without providing an adhesive or the like.

FIG. 9 shows a method for assembling the magnetic element 16. FIGS. 9A to 9C are assembly steps shown in perspective views. The magnetic component constituting the magnetic element 16 includes two components divided into a core 17 having a spacer 21 and an outer core 20. The outer core 20 is provided with an opening 20a into which the coil assembly 19 can be inserted and a groove 20b for fixing the coil assembly 19 in the outer core 20 in the vertical direction of the opening. A cylindrical core 17 is inserted in the coil 18 wound in advance in the arrow direction (FIG. 9A). Both end portions 17b of the cylindrical core core 17 are inserted in the direction of the arrow along the upper and lower grooves 20b provided on the inner peripheral surface of the outer peripheral core 20. This groove 20b also serves as positioning in the radial direction excluding the axial direction of the cylindrical core 17 and the one direction in which it is inserted (FIG. 9B). That is, the assembly 19 is fixed in the outer core 20 by being inserted along the groove 20b (FIG. 9C). Thus, in the present invention, the cylindrical core core 17 is inserted from the direction perpendicular to the coil axis direction, and the core core 17 is provided with the spacer fitted in advance, so that the insertion direction Positioning in the radial direction and the axial direction other than the above is unnecessary, the assembly is simplified, and the magnetic characteristics can be easily adjusted. Moreover, since it becomes the combination of the outer periphery core 20 and the cylindrical core core 17, the number of parts can be reduced. The core core 17 may have a polygonal shape other than the columnar shape as long as it is columnar.

Another example of the EEP type magnetic element with the spacer is shown in FIGS. FIG. 10A is a perspective view of the EEP type magnetic element, FIG. 10B is a cross-sectional view in the CC direction, and FIGS. 11A to 11D are assembly steps shown in the perspective view. The magnetic element 22 includes a coil assembly 25 in which a coil 24 in which a magnet wire is wound around an outer periphery of a cylindrical core core 23 provided with a pair of flange-shaped spacers 27 at both ends in the axial direction, and the coil assembly 25. And an outer peripheral core 26 covering the outer periphery of the outer periphery. The back surface 26b on the opposite side to the opening 26a side of the outer peripheral core 26 has a semicircular shape in plan view. Two spacers 27 are provided at both axial end surfaces of the cylindrical core core 23 made of a magnetic material. The diameter of the spacer 27 is larger than the diameter of the core core 23, and both are provided concentrically. The spacer 27 is formed in a flat plate cylindrical shape, and the axial end surface of the core core 23 is fitted inside the flat plate cylindrical shape.
The outer peripheral core 26 has a groove 26 c formed on the inner peripheral surface thereof, the outer periphery of the spacer 27 is inserted along the groove 26 c, and the outer periphery of the spacer 27 is in close contact, so that the coil assembly 25 is fixed in the outer core 26.

The spacer 27 is fitted in advance to both axial end surfaces 23a of the core core 23, and the coil 24 is prepared. The coil 24 may be obtained by winding a magnet wire directly around the core core 23, or a coil 24 around which a magnet wire is wound may be inserted into the core core 23 (FIGS. 11A and 11B). The coil assembly 25 is fixed in the outer core 26 when the outer peripheral surface of the spacer 27 is in close contact with the inner peripheral surface 26c of the outer core 26 (FIGS. 11C and 11D).

Another example of the EEP type magnetic element with the spacer is shown in FIGS. 12A is a perspective view of the EEP type magnetic element, FIG. 12B is a sectional view in the DD direction, and FIGS. 13A to 13C are assembly steps shown in the perspective view.
The magnetic element 28 includes a coil assembly 31 including a coil 30 in which a magnet wire is wound around the outer periphery of a cylindrical core core 29, and an outer core 32 covering the substantially outer periphery of the coil assembly 31. The outer core 32 is provided with a through hole 32 b in the outer core 32 into which the core 29 can be inserted.
A spacer 33 is fitted to the circumferential portion 29 a in the vicinity of the end surface in the axial direction of the cylindrical core core 29. The spacer 33 has a cylindrical shape, and is fitted to a circumferential portion 29 a that is a small-diameter portion provided in the vicinity of the axial end surface of the core core 29.

The coil 30 wound in advance is inserted from the opening 32a of the outer core 32 in the direction of the arrow (FIG. 13A), and the core 29 with the spacer is inserted in the direction of the arrow from the through hole 32b provided in the end face of the outer core 32. Insert (FIG. 13B). A coil assembly 31 composed of the coil 30 and the core core 29 is fixed in the outer core 32 (FIG. 13C). Moreover, since the end surface of the core core 29 excellent in thermal conductivity exists on the surface of the outer core 32, the heat dissipation of the magnetic element 28 is improved.

Another example of the EEP type magnetic element with the spacer is shown in FIGS. 14A is a perspective view of the EEP type magnetic element, FIG. 14B is a sectional view taken along the line EE, and FIGS. 15A to 15D are assembly steps shown in the perspective view.
The magnetic element 34 includes a coil assembly 37 including a coil 36 around which a magnet wire is wound around an outer periphery of a cylindrical core core 35, and an outer core 38 covering the outer periphery of the coil assembly 37. The outer core 38 has a through hole 38b in the outer core 38 into which the core 35 can be inserted.
Spacers 39 are provided on the circumferential portion and the end surface in the vicinity of both end surfaces in the axial direction of the cylindrical core core 35. The diameter of the spacer 39 is the same as the diameter of the core core 35, and both are provided concentrically. The spacer 39 is formed in a flat plate cylindrical shape, and the convex portion 35a on the axial end surface of the core core 35 is fitted into the flat plate cylindrical shape.

The spacers 39 are fitted from both ends of the core core 35, and the coil 36 wound in advance is inserted in the direction of the arrow from the opening 38a of the outer core 38, and from the through hole 38b provided in the end surface of the outer core 38. The core core 35 is inserted in the direction of the arrow (FIGS. 15A to 15C). A coil assembly 37 including a coil 36 and a core core 35 is fixed in the outer core 38 (FIG. 15 (d)).

In the present invention, the core core and the outer core are preferably molded magnetic bodies including a compression molded magnetic body and an injection molded magnetic body, and more preferably, the core core described above is a compression molded magnetic body, and the outer core is It is an injection-molded magnetic body.

In the present invention, compression-molded magnetic materials that can be used as the core are, for example, pure iron-based soft magnetic materials such as iron powder and iron nitride powder, Fe—Si—Al alloy (Sendust) powder, super Sendust powder, Ni—Fe. Magnetic materials such as iron-based alloy soft magnetic materials such as alloy (permalloy) powder, Co—Fe alloy powder, Fe—Si—B alloy powder, ferrite magnetic materials, amorphous magnetic materials, and fine crystal materials are used as raw materials. it can.

Ferrite magnetic materials include manganese zinc ferrite, nickel zinc ferrite, copper zinc ferrite, spinel ferrite having a spinel crystal structure such as magnetite, hexagonal ferrite such as barium ferrite and strontium ferrite, and garnet ferrite such as yttrium iron garnet. Can be mentioned. Among these ferrite-based magnetic materials, spinel ferrite, which is soft magnetic ferrite having high permeability and low eddy current loss in a high frequency region, is preferable. Examples of the amorphous magnetic material include iron alloy, cobalt alloy, nickel alloy, and mixed alloy amorphous thereof.

The oxide forming the insulating coating on the surface of the particles of the soft magnetic metal powder material as a raw _{_{_{material, Al 2 O 3, Y 2}}} O 3, MgO, insulating metal or metalloid oxides, such as ZrO _2, glass, These mixtures are mentioned. As a method for forming the insulating coating, a powder coating method such as mechanofusion, a wet thin film manufacturing method such as electroless plating or a sol-gel method, or a dry thin film manufacturing method such as sputtering can be used.

The compression-molded magnetic body is formed by compressing the raw material powder having an insulating coating formed on the particle surface, or a powder in which a thermosetting resin such as an epoxy resin is blended into the raw material powder into a green compact. It can be manufactured by firing a green compact. The ratio of the raw material powder is preferably 96 to 100% by mass, where the total amount of the raw material powder and the thermosetting resin is 100% by mass. If it is less than 96% by mass, the blending ratio of the raw material powder may decrease, and the magnetic flux density and permeability may decrease.

The average particle diameter of the raw material powder is preferably 1 to 150 μm. More preferably, it is 5 to 100 μm. When the average particle size is smaller than 1 μm, the compressibility at the time of pressure molding (a measure indicating the ease with which powder is solidified) is lowered, and the material strength after firing is significantly lowered. When the average particle diameter is larger than 150 μm, the iron loss in the high frequency region increases, and the magnetic characteristics (frequency characteristics) deteriorate.

Compressive molding can be performed by filling the above raw material powder into a mold and press molding with a predetermined pressure. The green compact is fired to obtain a fired body. When amorphous alloy powder is used as a raw material, the firing temperature needs to be lower than the crystallization start temperature of the amorphous alloy. Moreover, when using the powder with which the thermosetting resin was mix | blended, it is necessary to make baking temperature into the curing temperature range of resin.

In the present invention, an injection-molded magnetic body that can be used as an outer peripheral core can be obtained by blending a binder resin into the raw material powder of the compression-molded magnetic body and injection-molding this mixture. The magnetic powder is preferably an amorphous metal powder because of easy injection molding, easy shape maintenance after injection molding, and excellent magnetic properties of the composite magnetic material. As the amorphous metal powder, the above-described iron alloy series, cobalt alloy series, nickel alloy series, mixed alloy series amorphous, or the like can be used. The insulating coating described above is formed on the surface of these amorphous metal powders.

As the binder resin, a thermoplastic resin capable of injection molding can be used. Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene, polyvinyl alcohol, polyethylene oxide, polyphenylene sulfide (PPS), liquid crystal polymers, polyether ether ketone (PEEK), polyimide, polyether imide, polyacetal, polyether sulfone, and polysulfone. , Polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polyphthalamide, polyamide, and mixtures thereof. Among these, polyphenylene sulfide (PPS), which is excellent in fluidity at the time of injection molding when mixed with amorphous metal powder, can cover the surface of the molded article after injection molding with a resin layer, and has excellent heat resistance, etc. Is more preferable.

The ratio of the raw material powder is preferably 80 to 95% by mass, where the total amount of the raw material powder and the thermoplastic resin is 100% by mass. If it is less than 80% by mass, magnetic properties cannot be obtained, and if it exceeds 95% by mass, the injection moldability may be inferior.

Injection molding can be performed by, for example, a method of injecting and molding the raw material powder in a mold in which a movable mold and a fixed mold are abutted. The injection molding conditions vary depending on the type of thermoplastic resin. For example, in the case of polyphenylene sulfide (PPS), the resin temperature is preferably 290 to 350 ° C. and the mold temperature is preferably 100 to 150 ° C.

As a preferred embodiment, the compression-molded magnetic body serving as the core and the injection-molded magnetic body serving as the outer peripheral core are separately produced by the above-described method. Moreover, when bonding a compression molding magnetic body and an injection molding magnetic body, the solventless type epoxy-type adhesive which can mutually adhere is preferable.

As a preferable combination of materials of the compression molded magnetic body and the injection molded magnetic body, the compression molded magnetic body is preferably amorphous or pure iron powder, and the injection molded magnetic body is preferably an amorphous metal powder and a thermoplastic resin. More preferably, the amorphous metal is Fe—Si—Cr-based amorphous, and the thermoplastic resin is polyphenylene sulfide (PPS).

When the resin is sealed, a thermosetting resin is preferable as the sealing resin, and examples thereof include an epoxy resin, a phenol resin, and an acrylic resin that are excellent in heat resistance and corrosion resistance. As an epoxy resin, it has the same resin component as what was enumerated by the said resin binder, and a one-pack type or two-pack type epoxy resin etc. can be used. Moreover, as the curing agent in this epoxy resin, in addition to the latent epoxy curing agent, an amine curing agent, a polyamide curing agent, an acid anhydride curing agent and the like can be used as appropriate, and the curing temperature range and curing time are as described above. It is preferable to be the same as the resin binder. As the phenol resin, for example, a novolak type phenol resin or a resol type phenol resin can be used as a resin component, and hexamethylenetetramine can be used as a curing agent.

The spacer that can be used in the present invention can be used as long as it is a non-magnetic material. For example, the above-described materials such as thermoplastic resins as binder resins, thermosetting resins as sealing resins, ceramics, non-magnetic metals, etc. Can be used. The spacer can be formed into a cylindrical shape or a flat plate cylindrical shape by a method such as injection molding.

The magnetic element of the present invention can be provided with an inductor function by, for example, arranging a coil around which a magnet wire is wound around the compression molded magnetic body to form a coil assembly. This magnetic element is incorporated in an electric / electronic device circuit. An enameled wire can be used as the magnet wire, and the types thereof are urethane wire (UEW), formal wire (PVF), polyester wire (PEW), polyesterimide wire (EIW), polyamideimide wire (AIW), polyimide. A wire (PIW), a double coated wire combining these, a self-bonding wire, a litz wire, or the like can be used. Polyamideimide wire (AIW), polyimide wire (PIW) and the like excellent in heat resistance are preferred. A round wire or a square wire can be used as the cross-sectional shape of the magnet wire. In particular, a coil assembly with improved coil density can be obtained by winding the short axis side of the cross-sectional shape of the rectangular wire in contact with the periphery of the compression-molded magnetic body. The conductor of the magnet wire may be any metal having excellent conductivity, and examples thereof include copper, aluminum, gold, and silver.

The magnetic element of the present invention is used as a magnetic element used in power circuits, filter circuits, switching circuits, etc. of automobiles, industrial devices and medical devices including motorcycles, such as inductors, transformers, antennas, choke coils, filters, etc. it can. It can also be used as a surface mounting component. In particular, in the case of high efficiency DC / DC converters, charging devices, and inverters, when these uses are for photovoltaic power generation or in-vehicle use, downsizing and low profile are required. Therefore, the inductor of the present invention is preferably used. be able to.

An example in which the magnetic element of the present invention is used as a surface mounting component is shown in FIG. FIG. 16A is a partially cutaway perspective view showing a preferred mounting example of the magnetic element, and FIG. 16B is another mounting example.
As shown in FIG. 16 (a), the opening 5a of the outer core 5 is opposed to the electronic component substrate 40, so that the distance from the coil winding portion to the substrate 40 is shortened and the amount of magnet wire used is suppressed. it can. Further, the coil terminal 3a is taken out in the tangential direction of the coil 3 and can be surface-mounted on the substrate 40 with a minimum bending process, which contributes to a reduction in processing cost. Furthermore, since bending is less than the magnetic element shown in FIG. 16B, the direct current resistance can be reduced and the processing cost can be reduced. 16B, the opening 5a of the outer peripheral core 5 is an open surface, and at least one outer peripheral surface of the outer core 5 is in close contact with the substrate 40 and can be fixed. By doing so, the physique of the magnetic element is increased, but the magnetic element is excellent in heat dissipation.

Since the magnetic element of the present invention can reduce the number of parts and the number of manufacturing steps, it has excellent productivity and can be suitably used as a magnetic element for various electric / electronic devices.

1, 6, 11, 16, 22, 28, 34, 44

Magnetic element

2, 7, 12 17, 23, 29, 35, 45

Core core

3, 8, 13, 18, 24, 30, 36, 46 Coil 4 9, 14, 19, 25, 31, 37, 47

Coil assembly

5, 10, 15, 20, 26, 32, 38, 48

Outer core

21, 27, 33, 39, 49 Spacer 40 Substrate 41 Conventional magnetic element 42 Conventional outer core 43 Conventional coil

Claims

A magnetic element comprising a coil assembly in which a coil is disposed on the outer periphery of a core core, and an outer peripheral core covering the outer periphery of the coil assembly,
The outer peripheral core has an opening through which the coil assembly can be inserted, and a fixing means for fixing the coil assembly in the outer core.
The core core is a core core having a pair of flange portions provided at both axial ends of the columnar core core, and the fixing means has a shape in which the outer peripheral shape of the flange portion is in close contact with the inner peripheral surface of the outer peripheral core. The magnetic element according to claim 1, wherein the coil assembly is fixed in the outer peripheral core.
The core core is a columnar core, and the fixing means is provided inside the outer core, and a pair of grooves into which both axial ends of the columnar core can be inserted are provided on the inner peripheral surface of the outer core. The magnetic element according to claim 1, wherein the coil assembly is fixed in the outer peripheral core.
The core core is a columnar core, and the fixing means is configured to fix the coil assembly in the outer core by providing at least one through hole for inserting the core core in the outer core. The magnetic element according to claim 1.
The core core is a columnar core, and a spacer that fits with the columnar core in at least one of an axial intermediate portion, an axial end surface, and a circumferential portion in the vicinity of the axial end surface of the columnar core. The magnetic element according to claim 1, wherein the magnetic element is provided.
The magnetic element according to claim 1, wherein the outer peripheral core having the coil assembly fixed therein has a shape in which at least one outer peripheral surface of the outer peripheral core can be fixed to a substrate of an electronic device.
The magnetic element according to claim 1, wherein the core is a compression-molded magnetic body, and the outer core is an injection-molded magnetic body.