JP2016225441A - Magnetic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic element, such as a pot type inductor, which has a form in which a coil is covered with a magnetic material, achieves excellent cooling performance, and inhibits heat generation.SOLUTION: An inductor 1 serving as a magnetic element includes: a coil 5 formed by winding a wire; and a magnetic material 2 in which the coil 5 is disposed and allowing magnetic flux generated by the coil 5 to pass therethrough. The magnetic material 2 has an air-cooling part for air-cooling the magnetic element in a magnetic material outer diameter part covering an outer diameter side of the coil 5. The air-cooling part is formed by a slit 7 having a hole structure penetrating through the magnetic material outer diameter part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a magnetic element in which a coil is wound around a magnetic body and used as an inductor, a transformer, an antenna (bar antenna), a choke coil, a filter, a sensor, etc. in an electric device or an electronic device. . In particular, the present invention relates to a pot-type inductor in which a coil is surrounded by a magnetic material.

  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 providing a method for manufacturing 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). ).

Japanese Patent No. 4766609

  The magnetic element is required to reduce magnetic flux leakage and to reduce its physique. For example, a pot-type inductor that is a closed magnetic circuit with respect to an open magnetic circuit drum-shaped core has a small magnetic flux leakage and a small physique. This is because the pot-shaped inductor has a magnetic path so as to cover the coil, and the thickness of the magnetic body on the coil outer diameter side is smaller than the radius of the magnetic body on the coil inner diameter side. . In the above-mentioned patent document 1, since various shapes can be realized, it is possible to form a magnetic body shape that covers the coil.

  However, in such a pot-type inductor having a closed magnetic path, if no resin is filled in the gap between the coil and the core, an air flow hardly occurs around the coil, which is disadvantageous on the cooling surface.

  The present invention has been made in order to cope with such a problem. In a magnetic element having a shape in which a coil is covered with a magnetic material such as a pot-shaped inductor, a magnetic element that has excellent cooling performance and can suppress heat generation. An object is to provide an element.

  The magnetic element of the present invention is a magnetic element comprising a coil formed by winding a winding, and a magnetic body in which the coil is disposed and allows a magnetic flux generated by the coil to pass therethrough. A magnetic body outer diameter part covering the outer diameter side of the coil has an air cooling part for air-cooling the magnetic element, and the air cooling part has a hole structure penetrating the magnetic body outer diameter part or the magnetic body outer diameter part. It consists of the uneven structure provided in the outer peripheral part.

  The magnetic body is formed by combining a compression molded magnetic body disposed on the inner diameter side of the coil and an injection molded magnetic body disposed on the outer diameter side of the coil, and the compression molded magnetic body is the magnetic body. It is exposed on the surface, and the outer diameter part of the magnetic body is made of the injection-molded magnetic body. Further, the injection-molded magnetic body is a combined body in which magnetic bodies divided into two in the axial direction of the coil are combined with each other.

  The air cooling part has the hole structure, and the two-divided magnetic body has a complementary concave-convex shape that fits on the inner diameter side of each of the magnetic body outer diameter parts when they are coupled. To do. Further, the air cooling part has the hole structure, and a flange part is provided on the outer peripheral part of the outer diameter part of the magnetic body at the position of the coupling part of the two divided magnetic bodies.

  The air cooling part has the hole structure, and the terminal of the coil is taken out from the hole structure.

  The magnetic element of the present invention has a coil disposed inside a magnetic body, and has an air cooling portion for air-cooling the magnetic element on the outer diameter portion of the magnetic body that covers the outer diameter side of the coil. Since the hole structure (slit or window) penetrates the outer diameter part of the magnetic body, it is possible to generate an air flow that connects the inside and outside of the magnetic element, thereby improving the cooling performance. Moreover, since this air cooling part is the uneven structure provided in the outer peripheral part of the magnetic body outer diameter part, the surface area can be increased or the cooling performance of the outer peripheral part can be improved by following the flow of the surrounding air. . As a result, heat generation can be suppressed, and the physique of the inductor, which is a magnetic element, can be reduced.

  The magnetic body is formed by combining a compression molded magnetic body disposed on the inner diameter side of the coil and an injection molded magnetic body disposed on the outer diameter side of the coil, and the compression molded magnetic body is exposed on the surface. Since the outer diameter portion of the magnetic body is made of the injection-molded magnetic body, it is possible to improve the thermal conductivity on the coil inner diameter side, which is a location where heat generation due to iron loss is large or a location where heat dissipation is poor.

  Since the injection-molded magnetic body is a combined body in which magnetic bodies divided into two in the axial direction of the coil are combined with each other, after the magnetic body (divided body) is formed, the coil is inserted to connect the divided bodies A magnetic element can be manufactured. For this reason, compared with the case where it manufactures by insert molding, reduction of manufacturing equipment cost, improvement of productivity, reduction of manufacturing cost, etc. can be aimed at.

  The air cooling part has a hole structure, and (1) in the magnetic material divided into two, on the inner diameter side of each magnetic material outer diameter part, there is a complementary uneven shape that fits when they are combined, or (2) Since the flange portion is provided on the outer peripheral portion of the magnetic body outer diameter portion at the coupling portion position (coil insertion side end surface) of the two divided magnetic bodies, the outer diameter of the magnetic body is provided by providing a hole structure such as a slit or a window. It can suppress that a part opens to an outer-diameter direction. Further, for example, as the concavo-convex shape of (1), positioning at the time of coupling can be performed by providing an concavo-convex shape that rotates 180 degrees around an arbitrary axis on the coil insertion side end surface and meshes with each other.

  Since the air cooling part has a hole structure, and the coil terminal is taken out from the hole structure, the hole structure such as a slit or a window also serves as a coil terminal outlet, and the degree of freedom in handling the coil is increased. . That is, since the coil terminal can be taken out from any hole, there is no need to set a separate outlet.

It is an example of a pot type inductor. It is another example of a pot type inductor. It is a figure which shows the magnetic body in the inductor of FIG. It is a figure which shows the magnetic body in the inductor of FIG. It is another example (multiple slits) only of a magnetic body outer diameter part. It is another example (multiple slits and a flange part) only of a magnetic body outer diameter part. It is another example (complementary uneven | corrugated shape) only of a magnetic body outer diameter part. It is another example (outer peripheral part uneven structure) only of a magnetic body outer diameter part.

  The magnetic element of the present invention is suitable for a pot-shaped magnetic element (inductor) in which a coil is disposed inside a magnetic body. In general, a pot-shaped inductor can (1) provide a magnetic path so as to cover the coil, thereby reducing the leakage magnetic flux. (2) Thickness of the magnetic body on the coil outer diameter side compared to the radius of the magnetic body on the coil inner diameter side. Therefore, there is an advantage that the shape of the magnetic body can be reduced. However, the pot-type inductor does not have sufficient cooling performance as described above. Therefore, in the present invention, an air cooling part for air-cooling the magnetic element is provided in the outer diameter part of the magnetic body that covers the outer diameter side of the coil in order to improve the cooling performance.

  In addition, with the increase in frequency and electric current of electrical and electronic equipment, magnetic elements using ferrite materials obtained by the current mainstream compression molding method have excellent magnetic permeability, and it is easy to obtain inductance values, but frequency characteristics and superposition Inferior current characteristics. 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. Therefore, in a preferred embodiment of the present invention, the magnetic body on the inner diameter side of the coil, which is a part that easily generates heat or is difficult to dissipate heat, is a compression-molded magnetic body that is excellent in thermal conductivity (a part is exposed to the outside) and By using a pot-type hybrid inductor in which the radial-side magnetic body is an injection-molded magnetic body in which the air-cooling portion is arranged, a structure that suppresses heat generation and has excellent heat dissipation is realized.

An example of the magnetic element of the present invention is shown in FIGS. FIG. 1A is an axial sectional view of a pot-type inductor, and FIG. 1B is a plan view of the lower half divided at the axial center portion of the inductor. FIG. 3A is a perspective view of the magnetic body, and FIG. 3B is a perspective view of the lower half divided at the axial center portion of the magnetic body.
As shown in FIGS. 1A and 1B, the inductor 1 includes a coil 5 formed by winding a winding, and a magnetic body in which the coil 5 is disposed and through which a magnetic flux generated by the coil 5 passes. 2 are provided. The magnetic body 2 is disposed so as to cover substantially the entire coil 5. The magnetic body 2 is comprised by the below-mentioned injection molding magnetic body, for example. The magnetic body 2 is divided into two parts by an intermediate line 6 having an axial length, and is a combined body of these divided bodies (see FIG. 3). The two divided magnetic bodies have the same shape and can be manufactured with one mold.

  The present invention is characterized in that the pot-type inductor 1 having such a structure has a slit 7 having a hole structure penetrating from the outer peripheral surface of the outer diameter portion to the coil 5 in the outer diameter portion of the magnetic body 2. The coil 5 is inserted into the magnetic body 2 in a state where the magnetic body 2 is divided by the intermediate wire 6, and a resin or the like is not filled in the gap between the coil 5 and the magnetic body 2. The slit 7 can generate an air flow that connects the inside of the inductor (the part of the coil 5) and the outside, thereby improving the cooling performance. For example, the air introduced from the left (upper) slit 7 in FIG. 1 passes through the coil 5 and is also discharged from the right (lower) slit 7 in FIG. obtain.

Another example of the magnetic element of the present invention is shown in FIGS. FIG. 2A is an axial sectional view of the pot-type hybrid inductor, and FIG. 2B is a plan view of the lower half divided at the axial center portion of the inductor. FIG. 4A is a perspective view of the magnetic body, and FIG. 4B is a perspective view of the lower half divided at the axial center portion of the magnetic body.
As shown in FIGS. 2 (a) and 2 (b), the inductor 1 has a coil 5 formed by winding a coil, and the coil 5 is disposed inside, as in the case of FIG. 5 and a magnetic body 2 through which the magnetic flux generated by 5 passes. In this embodiment, the magnetic body 2 is configured by combining a compression molded magnetic body 4 disposed on the inner diameter side of the coil 5 and an injection molded magnetic body 3 disposed on the outer diameter side of the coil 5. In the magnetic body 2, both the compression-molded magnetic body 4 and the injection-molded magnetic body 3 are divided into two parts by the intermediate line 6 having an axial length, and are combined bodies of the respective divided bodies. Further, only the injection-molded magnetic body 3 may be a combined body of divided bodies that is divided into two by the intermediate line 6 having an axial length (see FIG. 4).

  In this embodiment, the outer diameter portion (injection molded magnetic body 3) of the magnetic body 2 has the slit 7 having the same structure as that in FIG. 1, and the same effect can be obtained. Further, the end face of the compression-molded magnetic body 4 is exposed on the surface of the inductor 1 (the center portion of the top surface and the bottom surface). For example, the exposed end surface is brought into contact with a cooling surface such as a substrate. As a result, heat conduction on the inner diameter side of the coil, which is difficult to dissipate, can be promoted.

  Other examples of the magnetic body outer diameter portion (such as injection-molded magnetic body) of the magnetic element of the present invention are shown in FIGS. 5 to 8 are perspective views of an injection-molded magnetic body in which (a) is an outer diameter portion of the magnetic body, and (b) is a perspective view of the lower half divided at the axial center portion of the injection-molded magnetic body. It is.

  The injection-molded magnetic body 3 shown in FIG. 5 has at least two slits 7 (eight places in the figure) at equal intervals in the circumferential direction. The slit 7 can improve the cooling effect as described above. Further, by making the width of the slit 7 smaller than the width of the adjacent column portion, a continuous magnetic path can be provided and the vertical positioning can be performed by the core instead of the coil. For this reason, the error of the characteristic by the change of magnetic path length can be suppressed.

  The injection-molded magnetic body 3 shown in FIG. 6 has eight slits 7 equally spaced in the circumferential direction, as in FIG. In this embodiment, the flange portion 8 is provided on the outer peripheral portion of the coupling portion position (coil insertion side end surface) of the injection-molded magnetic body 3 divided into two. Since the injection molded magnetic body 3 is reinforced by the flange portion 8 and the slit is provided in the circumferential direction, the injection molded magnetic body can be prevented from opening in the outer diameter direction. Moreover, you may provide the notch for several coil terminal outlets as needed.

  The injection-molded magnetic body 3 shown in FIG. 7 has four slits 7 at equal intervals in the circumferential direction. In this form, in the state divided into two, it has complementary uneven | corrugated shape 3a and 3b which fits in each inner diameter side at the time of these coupling | bonding. This uneven shape is formed in the inner diameter part of the joint part position (coil insertion side end face) of the injection-molded magnetic body 3 divided into two parts, whereby the contacted divided body can be positioned in the circumferential direction. Also, by providing the slit 7 at a position where the inner diameter is convex, a continuous magnetic body is arranged on the outer peripheral side when meshed with each other, and since the slit is provided, the injection molded magnetic body opens in the outer diameter direction. Can be suppressed.

  The injection-molded magnetic body 3 shown in FIG. 8 has one slit 7 in the circumferential direction and an uneven structure 9 on the outer peripheral portion. By providing an uneven surface along the air flow at the outer peripheral portion, the cooling performance of the outer peripheral portion can be improved. The concavo-convex shape shown in the figure is a shape suitable for the case where the inductor is arranged so that the axial direction of the inductor coincides with the vertical direction. In addition, the uneven | corrugated shape should just be what can aim at the improvement of cooling performance, and is not limited to what is shown to this figure.

  As mentioned above, although the pot type inductor was demonstrated as a magnetic element of this invention using FIGS. 1-8, each structure of the magnetic element of this invention is not limited to this. Moreover, in any case of FIGS. 1-8, the freedom degree of coil handling increases by making the slit which is a hole structure into a coil terminal extraction port.

  Examples of the compression-molded magnetic material that can be used in the present invention include pure iron-based soft magnetic materials such as iron powder and iron nitride powder, Fe-Si-Al alloy (Sendust) powder, super Sendust powder, and Ni-Fe alloy (Permalloy). Magnetic materials such as iron-based alloy soft magnetic materials such as powder, Co—Fe alloy powder, and Fe—Si—B alloy powder, ferrite magnetic materials, amorphous magnetic materials, and fine crystal materials can be used as raw materials.

  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.

Examples of the oxide that forms an insulating coating on the particle surface of the soft magnetic metal powder material that is the raw material include oxides of insulating metals or metalloids such as Al ₂ O ₃ , Y ₂ O ₃ , MgO, and 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 preparation method such as electroless plating or a sol-gel method, or a dry thin film preparation 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 5-100 micrometers. 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.

  For compression molding, a method of filling the raw material powder in a mold and press-molding with a predetermined pressure can be used. 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.

  The injection-molded magnetic body that can be used in the present invention is obtained by blending a binder resin with the above-mentioned compression-molded magnetic body raw material powder 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.

  For the injection molding, for example, a method of injecting and molding the raw material powder into a mold in which a movable mold and a fixed mold are abutted can be used. Although 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.

  The compression-molded magnetic body and the injection-molded magnetic body are separately manufactured and bonded to each other by the above-described method. Each shape is a shape that can be easily assembled by dividing the magnetic body, and is also suitable for compression molding and injection molding. For example, when a cylindrical magnetic body without a central shaft hole is manufactured, a columnar shape on the coil inner diameter side is formed as a compression molded magnetic body by compression molding, and a coil outer diameter side is manufactured as an injection molded magnetic body by injection molding. Thereafter, a cylindrical magnetic body is obtained by inserting or fitting a cylindrical compression molded magnetic body into a hole provided in the center of the injection molded magnetic body. Moreover, a cylindrical magnetic body can be manufactured by disposing the compression molded magnetic body in a mold and insert molding the injection molded magnetic body.

  Further, at least the injection-molded magnetic body among the magnetic bodies coupled to each other is preferably a magnetic body divided into two in the axial direction in which the coil is inserted, as shown in the respective drawings. Any two-division method may be used as long as the coil can be inserted, and equal division in the axial direction is preferable. The number of molds can be reduced by equal division. When an adhesive is used, a solventless epoxy adhesive that can adhere to each other 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).

  The inductor that is the magnetic element of the present invention can have an inductor function by, for example, forming a coil by winding a winding around the compression-molded magnetic body. This magnetic element is incorporated in an electric / electronic device circuit. A copper enameled wire can be used as the winding, and the types thereof are urethane wire (UEW), formal wire (PVF), polyester wire (PEW), polyesterimide wire (EIW), polyamideimide wire (AIW), A polyimide 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 copper enamel wire. In particular, a coil with improved winding density can be obtained by winding the short axis of the cross-sectional shape of the flat wire in contact with the periphery of the compression-molded magnetic body. Moreover, helical winding can be preferably employed as a method of winding the coil.

  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.

  Since the magnetic element of the present invention is excellent in cooling performance and can suppress heat generation, it can be suitably used as a magnetic element for various electric and electronic devices.

DESCRIPTION OF SYMBOLS 1 Inductor 2 Magnetic body 3 Injection molding magnetic body 4 Compression molding magnetic body 5 Coil 6 Intermediate line 7 Slit 8 Flange part 9 Uneven structure

Claims (6)

A magnetic element comprising: a coil formed by winding a winding; and a magnetic body in which the coil is disposed and through which a magnetic flux generated by the coil passes.
The magnetic body has an air cooling portion for air-cooling the magnetic element in a magnetic body outer diameter portion covering the outer diameter side of the coil, and the air cooling portion has a hole structure penetrating the magnetic body outer diameter portion, or A magnetic element comprising a concavo-convex structure provided on an outer peripheral portion of the magnetic body outer diameter portion.   The magnetic body is formed by combining a compression molded magnetic body disposed on the inner diameter side of the coil and an injection molded magnetic body disposed on the outer diameter side of the coil, and the compression molded magnetic body is the magnetic body. 2. The magnetic element according to claim 1, wherein the magnetic element is exposed on a surface, and the outer diameter portion of the magnetic body is made of the injection-molded magnetic body.   3. The magnetic element according to claim 2, wherein the injection-molded magnetic body is a combined body in which magnetic bodies divided into two in the axial direction of the coil are combined with each other. Having the hole structure as the air cooling part,
4. The magnetic element according to claim 3, wherein each of the two divided magnetic bodies has a complementary concavo-convex shape that fits on the inner diameter side of each of the magnetic body outer diameter portions when they are coupled. Having the hole structure as the air cooling part,
5. The magnetic element according to claim 3, wherein a flange portion is provided on an outer peripheral portion of the outer diameter portion of the magnetic body at a position of the coupling portion of the two divided magnetic bodies.   The magnetic element according to any one of claims 1 to 5, wherein the air cooling portion has the hole structure, and the terminal of the coil is taken out from the hole structure.