JP2017037888A - Magnetic powder mold coil and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive coil that can alleviate proximity effect and suppress AC resistance.SOLUTION: A magnetic powder mold coil 1 comprises: a coil member 2 formed by winding a lead wire 3 with an insulation coat 4; an insulation resin mold member 5 that molds the coil member 2; and magnetic powder 6 contained in the mold member. The magnetic powder 6 is arranged substantially uniformly in the mold member 5. The magnetic powder 6 may be or may not be arranged integrally around the lead wire 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coil in which magnetic powder is contained in a mold member, and a manufacturing method thereof.

  The coil using a magnetic plating wire (for example, patent document 1) can reduce a proximity effect and can suppress an alternating current resistance. However, since the magnetic plating wire is expensive, it becomes an expensive coil.

  Therefore, in Patent Document 2, a magnetic material-coated conductor that forms a magnetic layer around a conductor by applying a resin mixed with a plurality of magnetic bodies to the outer periphery of the conductor and then extending the resin to a predetermined thickness while applying pressure, and its A manufacturing method is disclosed. However, since this magnetic material-coated conductor also takes time to manufacture, it is more expensive than a general coil conductor. Therefore, it becomes an expensive coil.

Japanese Patent Laid-Open No. 62-151594 JP 2014-71969 A

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an inexpensive coil that can reduce the proximity effect and suppress the AC resistance.

  The magnetic powder mold coil according to claim 1, which has been made to achieve the above object, is obtained by molding a coil member having a shape in which a conductive wire with an insulating film is wound, and the coil member. It has the mold member which has the insulation which has and the magnetic powder contained in the said mold member, It is characterized by the above-mentioned.

  The magnetic powder mold coil according to claim 2 is the one according to claim 1, and the magnetic powder is composed of a single type of magnetic material having the same material, size, and shape, or Further, it is characterized in that it is composed of a plurality of types of magnetic materials that differ in at least one of material, size and shape.

  A magnetic powder mold coil according to a third aspect is the one according to the first or second aspect, wherein the magnetic powder is accumulated around the conducting wire.

  The magnetic powder mold coil described in claim 4 is the one described in claim 3, wherein at least a part of the magnetic powder has a flat shape, and the flat surface of the flat shape is the conductor. It arrange | positions substantially parallel with respect to the outer peripheral surface of this.

  A magnetic powder mold coil according to a fifth aspect is the one according to the first or second aspect, wherein the magnetic powder is disposed substantially uniformly in the mold member.

  The method of manufacturing a magnetic powder mold coil according to claim 6 makes a raw material of an insulating mold member into a liquid and mixes a plurality of magnetic powders with the liquid raw material of the mold member to create a mixed slurry. Then, a coil member having a shape in which a conductive wire with an insulating coating is wound is placed in a molding die formed corresponding to the mold shape, the mixed slurry is poured into the molding die, and the mixed slurry is poured into the coil member. The coil member is molded by impregnating and curing the mixed slurry.

  The method for manufacturing a magnetic powder mold coil according to claim 7 is the method according to claim 6, and a current is passed through the conductor of the coil member in a state where the coil member is impregnated with the mixed slurry. It is characterized by that.

  A method for manufacturing a magnetic powder mold coil according to an eighth aspect is the one according to the seventh aspect, wherein the magnetic powder is at least partially flat.

  In the magnetic powder mold coil and the manufacturing method thereof according to the present invention, the magnetic powder mold coil can be manufactured by mixing the magnetic powder into the mold member using the same conductive wire and mold member as the conventional winding coil. It can be manufactured at low cost. According to the magnetic powder mold coil of the present invention, since magnetic powder exists around the conducting wire, the magnetic flux generated when a current flows through the conducting wire passes through the magnetic powder, and the magnetic flux linked to the surrounding conducting wire is reduced. For this reason, since the eddy current generated in the surrounding conductors is reduced, the proximity effect can be reduced and the AC resistance can be suppressed.

  When the magnetic powder is accumulated around the conducting wire, since the conducting wire is covered with the magnetic powder, most of the magnetic flux passes through the magnetic powder, and the magnetic flux linked to the conducting wire is further reduced. Therefore, since the eddy current generated in the conducting wire is further reduced, the proximity effect can be further reduced and the AC resistance can be further suppressed. Further, when the magnetic powder has at least a part of a flat shape, and the flat shape of the flat shape is arranged substantially parallel to the outer peripheral surface of the conducting wire, the entire conductor is easily covered with the magnetic powder. AC resistance can be further suppressed. Such a method of manufacturing a magnetic powder mold coil can be manufactured by impregnating a coil member with a mixed slurry containing magnetic powder and passing a current through a conductor of the coil member. Since it is sufficient to use a general power supply device to flow the current, a special device is unnecessary, and the device can be manufactured simply and inexpensively.

It is sectional drawing which shows typically the magnetic powder mold coil to which this invention is applied. It is a figure which shows typically the manufacturing method of the magnetic powder mold coil to which this invention is applied. It is sectional drawing which shows typically the other magnetic powder mold coil to which this invention is applied. It is a figure which shows typically the principal part of the manufacturing method of the other magnetic powder mold coil to which this invention is applied. It is sectional drawing which shows the structure of the COW coil which is a comparative example which performed the simulation analysis. It is sectional drawing which shows the structure of the magnetic powder mold coil to which this invention which performed the simulation analysis is applied. It is a graph of the resistance-frequency characteristic of the coil which shows a simulation result. It is a contour diagram of current density distribution showing a simulation result. It is a contour figure of the magnetic field which shows a simulation result.

  Hereinafter, modes for carrying out the invention will be described in detail, but the scope of the present invention is not limited to these modes.

  FIG. 1 schematically shows a cross-sectional view and a partially enlarged cross-sectional view of a magnetic powder mold coil 1 to which the present invention is applied. The magnetic powder mold coil 1 includes a coil member 2, a mold member 5, and magnetic powder 6. In addition, in order to make an understanding of this invention easy, in each drawing, the magnitude | sizes of the magnetic powder 6 grade | etc., Are shown in bigger size than actual.

  The coil member 2 has a shape in which a conducting wire 3 with an insulating coating 4 is wound. For example, the coil member 2 is the same as a conventional wound coil. The conducting wire 3 is a long conductor used in a conventional winding coil. The cross-sectional shape of the conducting wire 3 may be a circular shape as shown in the figure, or may be a square shape or a polygonal shape. Moreover, the litz wire which twisted many conducting wires may be sufficient. The number of turns of the coil member 2, the winding diameter, the winding method (dense winding, loose winding, etc.), and the wire diameter and wire length of the conducting wire 3 are arbitrary.

  As the material of the conducting wire 3, for example, copper, copper alloy, aluminum, or aluminum alloy can be used in the same manner as the conducting wire material of the conventional wound coil. As the conducting wire 3, in addition to a general magnet wire, a Manganin (registered trademark) wire or a copper aluminum clad wire may be used. Since the conducting wire 3 is a member used for a conventional general winding coil, it is less expensive than a magnetic plating wire.

  The conducting wire 3 has an insulating coating 4 on its outer peripheral surface as shown in a partially enlarged sectional view in FIG. The insulating film 4 is an insulating film. As a material for the insulating coating 4, for example, an insulating resin such as enamel, polyimide, polyvinyl formal, polyurethane, polyester, polyesterimide, or polyamide can be used similarly to the insulating coating of a conventional wound coil. The film thickness of the insulating coating 4 is, for example, 1 to 100 μm, similarly to the conventional wound coil.

  The mold member 5 has an insulating property. The mold member 5 molds (seals) the entire coil member 2 (conductive wire 3). Insulation of varnish, epoxy, silicone, urethane, phenol, unsaturated polyester, polypropylene, polyethylene, ABS resin, or polycarbonate as the material of the mold member 5 as in the conventional mold coil (winding coil with mold member) Resin can be used. Since the mold member 5 is a member used for a conventional general mold coil, it is inexpensive.

  The magnetic powder 6 is disposed in the mold member 5. The magnetic powder 6 is a powdery (fine piece-like) magnetic substance (plural pieces). The magnetic powder 6 is desirably a soft magnetic powder such as iron powder, amorphous powder, ferrite powder, and Finemet (registered trademark) powder. Since various kinds of magnetic powder 6 are commercially available, they may be used as appropriate. The magnetic powder 6 can be manufactured, for example, by a spraying method. The magnetic powder 6 may be a finely pulverized soft magnetic material.

  The magnetic powder 6 is composed of a single type of magnetic material (magnetic powder) that is the same in material, size, and shape, or a plurality of types of magnetic materials that differ in at least one of the material, size, and shape. (Magnetic powder). Since the AC resistance of the magnetic powder mold coil 1 includes the iron loss of the magnetic powder 6, it is desirable to appropriately select the material, size, and shape of the magnetic powder 6 according to the frequency band to be used.

  Examples of the shape of the magnetic powder 6 include a spherical shape, a flat shape, a spheroid shape, a plate shape, a rectangular parallelepiped shape, and an indefinite shape. As shown in the figure, the magnetic powder 6 may have a plurality of different shapes, or may have only substantially the same shape. The magnetic powder 6 is preferably at least partially flat. The plate shape and the spheroid shape are included in the flat shape.

  Although the size of the magnetic powder 6 is not limited, for example, a magnetic powder having a length of about 0.1 to 500 μm is used. As an example, a flat body having a thickness of 0.1 to 10 μm and a width of 1 to 200 μm is used. Since the magnetic powder 6 is a general material, it is inexpensive.

  Since the outer peripheral surface of the conducting wire 3 is covered with the insulating coating 4, the magnetic powder 6 may come into contact with the coil member 2.

  According to this magnetic powder mold coil 1, since the magnetic powder 6 exists around the conducting wire 3, the magnetic flux generated when a current flows through the conducting wire 3 passes through the magnetic powder 6 and is interlinked with the surrounding conducting wire 3. Decrease. Therefore, since the eddy current generated in the surrounding conducting wire 3 is reduced, the proximity effect can be reduced and the AC resistance can be suppressed. As the amount of the magnetic powder 6 is increased, the proximity effect can be further reduced and the AC resistance can be further suppressed. In addition, the simulation analysis result about the reduction effect of the proximity | contact effect of the magnetic powder mold coil 1, ie, the suppression effect of alternating current resistance, is mentioned later.

  Next, the manufacturing method of the magnetic powder mold coil 1 to which the present invention is applied will be described.

  In FIG. 2, the manufacturing process of the magnetic powder mold coil 1 is shown typically. As shown in FIG. 2A, magnetic powder 6 is prepared in advance.

  As shown in FIG. 2B, a mold liquid 11 is prepared in which the raw material of the mold member having insulation properties is made liquid. Conventionally, when the coil is molded, since the raw material of the molding member is liquefied, it may be liquefied by a method similar to the conventional method using the same raw material. For example, the raw material of the mold member 5 having thermoplasticity may be heated to a temperature equal to or higher than the melting point and melted to make a liquid. The raw material of the mold member 5 may be dissolved in a liquid organic solvent to make it liquid. If the raw material is liquid, it may be used as it is. For example, a two-component curable mold member that cures when two components are mixed may be used. A thermosetting mold member that cures when the liquid is heated may be used.

  Next, as shown in FIG. 2C, a plurality of magnetic powders 6 and a mold liquid 11 are mixed to form a liquid mixed slurry 12. Stir well to mix the mixed slurry 12 evenly. The surface of the magnetic powder 6 coated with a surfactant may be used so that the magnetic powder 6 does not aggregate.

  Next, as shown in FIG. 2D, the coil member 2 is placed in a forming die 91 formed in correspondence with the mold shape. The coil member 2 and the mold 91 are manufactured in advance. The coil member 2 may be manufactured by, for example, a winding machine in the same manner as a conventional winding coil. The molding die 91 may be manufactured in the same manner as that for manufacturing a conventional molded coil. As shown in the figure, the liquid mixed slurry 12 is poured into a molding die 91, and the coil member 2 (conductor 3) is immersed in the mixed slurry 12 as shown in FIG. The member 2 is impregnated with the mixed slurry 12.

  Next, the coil member 2 is molded by curing the mixed slurry 12 (molding liquid 11). When the mixed slurry 12 is mixed substantially evenly, the magnetic powder 6 is arranged substantially evenly in the mold member 5. What is necessary is just to harden the mold liquid 11 similarly to the hardening method of the conventional mold member. For example, a thermoplastic mold member heated to a melting point or higher and liquefied is cooled to a temperature lower than the melting point and cured. Alternatively, the mold member dissolved in the organic solvent is heated or dried to evaporate the organic solvent and cure. Alternatively, the curing time of the two-component curable mold member is allowed to elapse to be cured. In the case of a mold member that is cured by heating, it is cured by heating. After curing, the magnetic powder mold coil 1 shown in FIG.

  The manufacture of the magnetic powder mold coil 1 is desirably performed by vacuum casting for defoaming. The magnetic powder mold coil 1 may be manufactured by injection molding or transfer molding.

  The magnetic powder mold coil and the manufacturing method thereof according to the present invention can be manufactured simply by mixing the inexpensive magnetic powder 6 into the mold member 5 using the conductive wire 3 and the mold member 5 similar to those of the conventional winding coil. The magnetic powder mold coil 1 can be manufactured at low cost. Magnetic plating wire is difficult to manufacture unless it is a wire manufacturer, but the magnetic powder mold coil of the present invention uses a conventional device without introducing a new manufacturing device if it is a factory that can manufacture a mold coil. And can be manufactured.

  Next, another magnetic powder mold coil to which the present invention is applied will be described. In addition, the same code | symbol is attached | subjected about the structure similar to the already demonstrated structure, and detailed description is abbreviate | omitted.

  FIG. 3 schematically shows a cross-sectional view and a partially enlarged cross-sectional view of a magnetic powder mold coil 1A to which the present invention is applied. The magnetic powder mold coil 1 </ b> A includes a coil member 2, a mold member 5 </ b> A, and magnetic powder 6.

  In the magnetic powder mold coil 1 </ b> A, the magnetic powder 6 in the mold member 5 </ b> A is integrated and disposed around the conductor 3 as shown in a partially enlarged cross-sectional view in FIG. The material of the mold member 5A is the same as that of the mold member 5.

  When a plurality of magnetic powders 6 are accumulated around the conducting wire 3 as in the magnetic powder mold coil 1A, the conducting wire 3 is covered with a magnetic material, so that the magnetic flux linked to the conducting wire 3 is further reduced. . Therefore, the proximity effect can be further reduced as compared with the magnetic powder mold coil 1 described above, and the AC resistance can be further suppressed.

  Further, the magnetic powder mold coil 1 </ b> A includes a plurality of magnetic powders 6 including at least a part of a flat magnetic powder 6, and the flat flat surface is substantially parallel to the outer peripheral surface of the conducting wire 3. It is desirable that they are arranged. If the flat surface of the magnetic powder 6 is arranged substantially parallel to the outer peripheral surface of the conducting wire 3, the entire conducting wire 3 is easily covered without any gap by the magnetic powder 6, thereby further reducing the influence of the proximity effect. Can do.

  Next, a method for manufacturing the magnetic powder mold coil 1A will be described.

  In order to manufacture this magnetic powder mold coil 1A, the same steps as FIG. 2 (e) before curing from FIG. 2 (a) of the method for manufacturing the magnetic powder mold coil 1 described with reference to FIG. I do. In other words, a mixing slurry 12 is prepared by mixing the magnetic powder 6 and the mold liquid 11, and a molding die 91 in which the coil member 2 having a shape in which the conductive wire 3 with the insulating coating 4 is wound is formed corresponding to the mold shape. The mixed slurry 12 is poured into the mold 91 and the coil member 2 is impregnated in the mixed slurry 12.

  As shown in the partially enlarged view schematically shown in FIG. 4, in order to manufacture the magnetic powder mold coil 1 </ b> A, the coil member 2 is impregnated with the mixed slurry 12 and the conductor 3 of the coil member 2 is impregnated. A step of flowing current I (for example, direct current) is performed. As shown in the figure, when a current I is passed through the conducting wire 3, a concentric magnetic field H is generated around the conducting wire 3. The magnetic field H is larger as it is closer to the conductor 3. Therefore, the magnetic powder 6 in the mixed slurry 12 is attracted to the conducting wire 3 and gathers and accumulates around the conducting wire 3 (outer peripheral surface). Since the outer peripheral surface of the conducting wire 3 is covered with the insulating coating 4, the conducting wire 3 and the magnetic powder 6 are electrically insulated, so the magnetic powder 6 may contact.

  When at least part of the magnetic powder 6 has a flat shape, the magnetic powder 6 gathers around the conductor 3 while the direction of the magnetic field H and the flat shape of the flat surface are aligned in parallel under the influence of the magnetic field H. . Therefore, the flat surface of the magnetic powder 6 is disposed substantially parallel to the outer peripheral surface of the conducting wire 3.

  In the state shown in the figure, the mixed slurry 12 (mold liquid 11) is cured. What is necessary is just to stop the electric current I sent through the conducting wire 3 after the mold liquid 11 hardens | cures and the magnetic powder 6 is fixed. After curing, the magnetic powder mold coil 1A is completed by taking out from the mold 91.

<Simulation analysis>
Using a finite element method (FEM) analysis, the resistance-frequency characteristics of a COW (copper wire) coil using a copper wire as a comparative example and the magnetic powder mold coil of the present invention were calculated, compared, and examined.

  FIG. 5 shows the structure of the analyzed COW coil, and FIG. 6 shows the structure of the analyzed magnetic powder mold coil. In either case, the coil is obtained by winding a copper wire with a conductor diameter of 1.45 mm 69 times. In both coils, the copper wire is wound around eight layers from the first layer to the eighth layer, counting from the central axis side. First layer: 9 times, second layer: 9 times, third layer: 8 times 4th layer: 9 times, 5th layer: 8 times, 6th layer: 9 times, 7th layer: 8 times, 8th layer: 9 times. In the magnetic powder mold coil of FIG. 6, the entire copper wire is impregnated with magnetic powder. In the analysis, applying an insulating film around the conducting wire is omitted because the influence is small.

Table 1 shows the analysis conditions. The calculated frequency range is from 1 Hz to 100 kHz. The resistivity of the magnetic material was infinite.

<Analysis results>
FIG. 7 shows resistance-frequency characteristics of the COW coil, the magnetic powder mold coil of the present invention, and the one-turn coil. The one-turn coil is a reference example, and is a copper wire having the same conductor diameter and length as that of the copper wire used in the COW coil. From the result of the one-turn coil, it can be seen that the skin effect is small and the proximity effect is large.

  When the frequency was 10 kHz and 20 kHz, the resistance of the magnetic powder mold coil was 18% and 4% larger than the resistance of the COW coil, respectively. On the other hand, at 100 kHz, the resistance of the magnetic powder mold coil was 35% smaller than that of the COW coil.

  8 and 9 show the current density distribution and magnetic field strength at 10 kHz and 100 kHz of the COW coil and the magnetic powder mold coil of the present invention. In FIG. 8, it can be evaluated that the smaller the current density deviation (the smaller the color change) is, the smaller the eddy current is and the less the influence of the proximity effect is. In FIG. 9, it can be evaluated that the smaller magnetic field in the copper wire (the smaller the color change) is, the smaller the interlinkage magnetic field is and the less the influence of the proximity effect.

  From FIG. 8, the current density bias at 10 kHz is larger in the magnetic powder mold coil than in the COW coil. This is because, as shown in FIG. 9, the magnetic field in the magnetic powder mold coil is larger than the magnetic field in the COW coil and is strongly influenced by the proximity effect. On the other hand, at 100 kHz, the current density bias is smaller in the magnetic powder mold coil than in the COW coil. This is because, from FIG. 9, the magnetic field in the copper wire of the magnetic powder mold coil is smaller than that of the COW coil, thereby suppressing the proximity effect.

  In the above analysis results, the AC resistance was reduced in a frequency range of 50 kHz or more by impregnating the coil with magnetic powder. When the frequency was 100 kHz, the resistance of the magnetic powder mold coil was reduced by 35% compared to the resistance of the COW coil.

  According to the magnetic powder mold coil of the present invention, it has been found that the influence of the proximity effect can be reduced by the frequency band, and the AC resistance can be reduced. Under the analysis conditions, the AC resistance was reduced in the frequency range of 50 kHz or higher. The frequency characteristic can be changed by changing the conditions.

  1 · 1A is a magnetic powder mold coil, 2 is a coil member, 3 is a conductor, 4 is an insulation coating, 5 · 5A is a mold member, 6 is a magnetic powder, 11 is a molding liquid, 12 is a mixed slurry, 91 is a mold, H is a magnetic field and I is a current.

Claims (8)

A coil member having a shape in which a conductive wire with an insulating film is wound;
An insulating mold member molding the coil member;
A magnetic powder mold coil comprising magnetic powder contained in the mold member.   The magnetic powder is composed of a single type of magnetic material that is the same in material, size, and shape, or composed of a plurality of types of magnetic materials that differ in at least one of the material, size, and shape. The magnetic powder mold coil according to claim 1, wherein:   The magnetic powder mold coil according to claim 1, wherein the magnetic powder is accumulated around the conducting wire.   4. The magnetic powder according to claim 3, wherein at least a part of the magnetic powder has a flat shape, and the flat surface of the flat shape is arranged substantially parallel to an outer peripheral surface of the conducting wire. Magnetic powder mold coil.   The magnetic powder mold coil according to claim 1, wherein the magnetic powder is disposed substantially uniformly in the mold member. The material of the mold member having insulation is made into a liquid,
A plurality of magnetic powders and a liquid raw material for the mold member are mixed to create a mixed slurry,
Put the coil member in the shape of winding the conducting wire with insulation coating into the molding die formed corresponding to the mold shape,
Pouring the mixed slurry into the mold and impregnating the coil member with the mixed slurry;
A method of manufacturing a magnetic powder mold coil, comprising: curing the mixed slurry and molding the coil member.   The method of manufacturing a magnetic powder mold coil according to claim 6, wherein a current is passed through the conductive wire of the coil member in a state where the coil member is impregnated with the mixed slurry.   The method for manufacturing a magnetic powder mold coil according to claim 7, wherein at least a part of the magnetic powder is a flat shape.