JP2015026736A - Reactor and method of manufacturing the same - Google Patents

Abstract

In a reactor having a core made of a magnetic powder mixed resin, a reactor capable of easily improving the filling rate of magnetic powder in the core is provided. A reactor includes a coil that generates a magnetic flux when energized, and a core that is formed by curing a magnetic powder mixed resin and embedded in the coil. The magnetic powder mixed resin 21 includes a plurality of magnetic powder aggregates 220 that are formed into a granular shape by aggregating the magnetic powder 22 and an insulating resin 23 that encloses the plurality of magnetic powder aggregates 220 in a dispersed state. [Selection] Figure 4

Description

  The present invention relates to a reactor and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, for example, in an electric vehicle, a hybrid vehicle, and the like, a power conversion device such as an inverter or a converter is used in order to generate a drive current that is passed through an AC motor that is a power source. In such a power conversion device, a semiconductor module constituting a part of the power conversion circuit and a cooler for cooling the semiconductor module are provided, and a reactor or the like is included in a part of the step-up / down circuit for stepping up or stepping down the input voltage The electronic parts are provided.

  As the reactor, a coil is embedded in a magnetic powder mixed resin including magnetic powder and an insulating resin encapsulated in a state where the magnetic powder is dispersed, and a core obtained by curing the magnetic powder mixed resin is used as a core. (Patent Document 1).

JP 2006-4957 A

  In the reactor, in order to improve the performance of the reactor, it is conceivable to increase the filling rate of the magnetic powder in the magnetic powder mixed resin. This is because an improvement in the saturation magnetic flux density of the core and a reduction in iron loss in the core can be expected. However, simply increasing the filling amount of the magnetic powder in the magnetic powder mixed resin may make it difficult to uniformly disperse the magnetic powder in the insulating resin due to excessively high viscosity in the magnetic powder mixed resin. is there. Therefore, there is room for improvement in order to sufficiently increase the filling rate of the magnetic powder.

  The present invention has been made in view of such problems, and in a reactor having a core made of a magnetic powder mixed resin, it is intended to provide a reactor that can easily improve the filling rate of magnetic powder in the core. is there.

One embodiment of the present invention includes a coil that generates magnetic flux when energized;
A core obtained by curing a magnetic powder mixed resin and having the coil embedded therein;
With
The magnetic powder mixed resin is characterized by comprising a plurality of magnetic powder aggregates formed into a granular shape by aggregating magnetic powders and an insulating resin containing the plurality of magnetic powder aggregates in a dispersed state. There is a reactor to do.

Another aspect of the present invention is an assembly forming step in which magnetic powders are aggregated to form a plurality of granular magnetic powder aggregates;
A coil placement step of placing a coil that generates magnetic flux when energized in a case;
An assembly arrangement step of arranging the plurality of magnetic powder assemblies in the case on which the coil is placed;
A mixed resin forming step of pouring a liquid insulating resin into the case in which the plurality of magnetic powder aggregates are arranged to disperse the plurality of magnetic powder aggregates in the insulating resin to form a magnetic powder mixed resin; and
A curing step of curing the magnetic powder mixed resin formed in the mixing step;
It is in the manufacturing method of the reactor characterized by including.

  In the reactor, in the magnetic powder mixed resin, a plurality of magnetic powder aggregates formed by collecting magnetic powder into a granular shape are dispersed in the insulating resin. Since the magnetic powder aggregate has a larger average particle size than the magnetic powder, the viscosity of the magnetic powder mixed resin is lower than the viscosity of the magnetic powder mixed resin in which the same amount of magnetic powder as the magnetic powder aggregate is dispersed. . For this reason, it is easy to uniformly disperse the magnetic powder aggregate in the insulating resin, so that the filling rate of the magnetic powder in the magnetic powder mixed resin can be easily improved. As a result, it is possible to improve the saturation magnetic flux density of the core and reduce the iron loss in the core, and contribute to the miniaturization of the entire reactor.

  According to the manufacturing method of the reactor, it is possible to manufacture a reactor that exhibits the above-described effects.

  As described above, according to the present invention, in the reactor having the core made of the magnetic powder mixed resin, it is possible to provide a reactor that can easily improve the filling rate of the magnetic powder in the core.

Sectional drawing of the reactor in Example 1. FIG. 2 is a partially enlarged view of the magnetic powder mixed resin in Example 1. FIG. FIG. 3 is an enlarged schematic view of a magnetic powder aggregate in Example 1. The schematic diagram showing the manufacturing method of the reactor in Example 1. FIG. The figure which shows the relationship between the filling rate of a magnetic powder and iron loss in Example 1. FIG. FIG. 3 is a graph showing the particle size distribution of magnetic powder in Example 1. The figure which shows the relationship between the filling rate of a magnetic powder in Example 1, and a viscosity. The figure explaining the process of impregnating resin in a magnetic powder composite in Example 1. FIG. The figure which shows the state which impregnated resin in the magnetic powder composite in Example 1. FIG. The figure which shows the relationship between the impregnation distance of resin and elapsed time in Example 1. FIG. The schematic diagram of the flow path in magnetic powder mixed resin in Example 1. FIG. The figure which shows the relationship between the impregnation distance of resin and elapsed time in Example 1. FIG.

  The reactor of this invention can be used for power converters, such as an inverter and a converter, which are mounted in an electric vehicle or a hybrid vehicle.

Example 1
About the reactor which concerns on the Example of this example, it demonstrates using FIGS.
As shown in FIGS. 1 and 2, the reactor 1 of this example includes a coil 10 that generates a magnetic flux when energized, and a core 20 in which the magnetic powder mixed resin 21 is cured and the coil 10 is embedded therein. With.
As shown in FIGS. 2 and 3, the magnetic powder mixed resin 21 includes a plurality of magnetic powder aggregates 220 in which the magnetic powder 22 is aggregated and formed into a granular shape, a plurality of magnetic powder aggregates 220, and an insulating resin 23. And mixed.

Hereinafter, the reactor 1 of this example is explained in full detail.
The coil 10 is formed by winding a copper wire into a cylindrical shape a predetermined number of times. As shown in FIG. 1, the coil 10 is housed in a cylindrical case 30 while being embedded in the core 2. The case 30 is open on the upper surface side (one end side in the winding axis direction Z of the coil 10).

  The magnetic powder 22 is a soft magnetic metal powder and includes, for example, Fe, Fe—Si alloy, Co, Ni, Fe—Ni alloy, Fe—Al alloy, Fe—Co alloy, Fe—Cr alloy, Fe— N alloy, Fe-C alloy, Fe-B alloy, Fe-P alloy, Fe-Al-Si alloy can be used. In this example, Fe-6.5% Si powder was used as the magnetic powder 22. The average particle diameter D50 of the magnetic powder 22 can be set to, for example, 10 to 500 μm. In this example, the average particle diameter D50 of the magnetic powder 22 is 140 μm. As shown in FIG. 3, an insulating coating 24 is formed on the surface of the magnetic powder 22. The insulating coating 24 is, for example, phosphoric acid type, resin type, or metal oxide. In this example, a phosphoric acid-based insulating coating 24 is formed on the surface of the magnetic powder 22. The thickness of the insulating coating 24 can be appropriately selected in consideration of the required strength of the insulating coating 24 and the type of the insulating coating 24 employed, and can be set to, for example, 10 nm to 1 μm.

  As shown in FIG. 3, the magnetic powder aggregate 220 is formed into a granular shape by assembling the magnetic powder 22. As a method of forming the magnetic powder aggregate 220, for example, compression molding in which the magnetic powder 22 is compressed and aggregated by a predetermined compacting apparatus can be employed. In the present specification, the term “granular” is not limited to a spherical shape, but refers to a broad concept including various shapes. Further, in this specification, the “average particle diameter” in the magnetic powder aggregate 220 means an average value of the diameter when the shape is spherical, and is the most in the shape when the shape is other than spherical. It shall mean the average value of the length of the long part.

The magnetic powder aggregate 220 includes a first magnetic powder aggregate 221, a second magnetic powder aggregate 222, and a third magnetic powder aggregate 223. The first magnetic powder aggregate 221, the second magnetic powder aggregate 222, and the third magnetic powder aggregate 223 are all formed in a granular shape.
The average particle diameter D50 of the first magnetic powder aggregate 221 can be set to 1.0 to 5.0 mm, for example, and is set to 3.0 mm in this example. As shown in FIG. 3, the particle size d1 of the first magnetic powder aggregate 221 is about 20 times the particle size d2 of the magnetic powder 22.
The average particle diameter D50 of the second magnetic powder aggregate 222 can be, for example, 0.3 to 0.5 times the average particle diameter D50 of the first magnetic powder aggregate 221. The average particle diameter D50 of the powder aggregate 221 was 0.4 times 1.2 mm.
The average particle diameter D50 of the third magnetic powder aggregate 223 can be, for example, 0.1 to 0.3 times the average particle diameter D50 of the first magnetic powder aggregate 221. The average particle diameter D50 of the powder aggregate 221 was 0.2 mm, 0.6 mm.

  The content ratio of the first magnetic powder aggregate 221, the second magnetic powder aggregate 222, and the third magnetic powder aggregate 223 included in the magnetic powder aggregate 220 is, for example, a required filling rate, a material of the insulating resin, It can be determined appropriately in consideration of the material of the magnetic powder. In this example, the volume ratio in the magnetic powder resin 21 was set to the first magnetic powder aggregate 221: the second magnetic powder aggregate 222: the third magnetic powder aggregate 223 = 92: 6: 2. Further, in this example, the magnetic powder resin 21 includes the magnetic powder 22 that does not form the magnetic powder aggregate 220. In addition, in addition to the first magnetic powder aggregate 221, the second magnetic powder aggregate 222, and the third magnetic powder aggregate 223, a mixture of the magnetic powder 22 that does not form the magnetic powder aggregate 220 is magnetically mixed. It may be called a powder aggregate 220.

  As the insulating resin, for example, an epoxy resin, a silicone resin, a PPS (polyphenylene sulfide) resin, or the like can be used.

Next, the reactor 1 of this example was produced by the following method.
First, magnetic powder 22 was prepared. And as shown to Fig.4 (a), the magnetic powder 22 was thrown into the compaction apparatus 401. FIG. A magnetic powder assembly including a first magnetic powder assembly 221, a second magnetic powder assembly 222, and a third magnetic powder assembly 223, which is obtained by compressing the magnetic powder 22 at 1000 MPa and collecting the particles in a granular form by a compactor 401. 220 was produced (aggregate production step).

Next, the first magnetic powder aggregate 221, the second magnetic powder aggregate 222, and the third magnetic powder aggregate 223 were heated at 800 ° C. for a predetermined time by the heating device 402, and then slowly cooled and annealed ( Annealing process).
Thereafter, as shown in FIG. 4B, a predetermined amount of the first magnetic powder aggregate 221, the second magnetic powder aggregate 222, the third magnetic powder aggregate 223, and the magnetic powder 22 are taken out into a blender 403. And mixed sufficiently so that each of them was uniformly dispersed (aggregate mixing step).

Next, the coil 10 was placed in the case 30 as shown in FIG. (Coil placement process). The coil 10 was placed so that one end side in the winding axis direction Z was the opening side of the case 30.
And as shown in FIG.4 (d), the magnetic powder aggregate 220 after the said mixing was arrange | positioned in the case 30 which mounted the coil 10 (mixed body arrangement | positioning process). After placing a predetermined amount of the magnetic powder aggregate 220 in the case 30, the case 30 was depressurized to a degree of vacuum of 1000 Pa in a vacuum chamber (not shown). Under reduced pressure, as shown in FIG. 4 (e), a predetermined amount of the liquid insulating resin 23 was poured onto the magnetic powder aggregate 220 by the dropping funnel 704. Thereafter, the inside of the vacuum chamber was returned to atmospheric pressure, and the magnetic resin aggregate 220 was impregnated with the insulating resin 23 by atmospheric pressure. As a result, as shown in FIG. 4 (f), the magnetic powder aggregate resin 220 was dispersed in the insulating resin 23 and contained therein, thereby producing the magnetic powder mixed resin 21 in the case 30 (mixed resin). Forming step). Thereafter, the magnetic powder mixed resin 21 was heated together with the case 30 to cure the magnetic powder mixed resin 21 (curing step). Thereby, the core 20 which embedded the coil 10 inside was formed, and the reactor 1 was produced.

(Verification test 1)
A verification test was conducted on the relationship between the filling rate of the magnetic powder and the core iron loss.
As shown in FIG. 5, for the samples a to d, ring-shaped test pieces in which the filling rate of each magnetic powder was changed were manufactured, and the iron loss at a frequency of 10 kHz and a magnetic flux density of 50 mT was measured. The composition of each sample ad is as follows.
Sample a: Fe-6.5% Si powder (average particle diameter D50 = 140 μm)
Sample b: Fe-3% Si powder (average particle diameter D50 = 140 μm)
Sample c: Fe-9.5% Si-5.5% Al powder (average particle size D50 = 30 μm)
Sample d: Fe-based amorphous powder (average particle diameter D50 = 30 μm)

  As shown in FIG. 5, it is confirmed that the iron loss is significantly reduced by increasing the filling rate of each magnetic powder in the range of about 55% to 70% for all the samples a to d. did.

(Verification test 2)
A verification test was performed on the relationship between the powder filling condition and the filling rate. Samples 1 to 9 were prepared by filling the cases with the following powders as follows.
Sample 1: Fe-6.5% Si powder (average particle diameter D50 = 140 μm) (hereinafter referred to as iron powder A) by gas atomization method was naturally poured into a case under atmospheric pressure and filled.
Sample 2: Iron powder A was poured into a case under reduced pressure with a vacuum degree of 1000 Pa and filled.
Sample 3: Iron powder A was poured and filled in a case under a reduced pressure of 20 Pa in vacuum.
Sample 4: After iron powder A was naturally poured into the case under atmospheric pressure, the case was tapped a predetermined number of times.
Sample 5: Iron powder A was naturally poured into a case under atmospheric pressure, and then was vibrated at a frequency of 10 Hz for a predetermined time by a vibration device.
Sample 6: Iron powder A was naturally poured into a case under atmospheric pressure, and then was vibrated at a frequency of 200 Hz for a predetermined time by a vibration device.
Sample 7: Fe-6.5% Si powder (average particle diameter D50 = 140 μm) (hereinafter referred to as iron powder B) by a water atomization method was naturally poured into a case and filled under atmospheric pressure. The iron powder B had a particle size distribution wider than the particle size distribution of the iron powder A, as shown in FIG.
Sample 8: Fe-6.5% Si powder (average particle diameter D50 = 140 μm) (hereinafter referred to as iron powder C) obtained by a water atomization method was naturally poured into a case and filled under atmospheric pressure. As shown in FIG. 6, the iron powder C has a particle size distribution wider than the particle size distribution of the iron powder A, and in the particle size distribution, in addition to having a peak at a particle size of 220 μm like the iron powder B, It also had a peak at a diameter of 40 μm.
Sample 9: Iron powder C was poured into a case under a reduced pressure of 1000 Pa in vacuum, and then was vibrated at a frequency of 200 Hz for a predetermined time by a vibration device.

  For Samples 1 to 9, the powder filling rate in the dry state was measured, and the measurement results are shown in Table 1. In addition, the increase value in the samples 2 to 8 indicates a difference from the filling rate of the sample 1, and the increase value in the sample 9 indicates a difference from the filling rate of the sample 8.

  As shown in Table 1, since the filling rate of sample 7 is 1.7% higher than that of sample 1, it is confirmed that the filling rate is improved by using iron powder B having a wide particle size distribution. did. Furthermore, since the filling rate of the sample 8 is 3.4% higher than that of the sample 7, by using the iron powder C having a peak at a particle size of 40 μm with respect to the iron powder B, It was confirmed that the filling rate was effectively improved. And since the filling rate of the sample 9 rose 11.9% compared with the sample 8, even when the iron powder C was used, it confirmed that a filling rate improved by pressure reduction and vibration. From the above, it was confirmed that the filling rate was effectively improved by controlling the particle size of the iron powder to be filled, in particular, by using iron powder having a plurality of peaks in the particle size distribution.

  It can be explained by the Horsfield theory that the packing rate can be improved by combining particles having different particle diameters when packing particles closely. That is, when filling true spheres (primary spheres), which are model particles having a single particle size, the packing ratio is 74.1% by volume by using so-called hexagonal close-packing. Can be filled. Further, when a secondary sphere that is a model particle having a smaller particle diameter than the primary sphere is added, when the secondary sphere has a particle size ratio of 0.414 with respect to the primary sphere, the filling rate is 79. 3% by volume can be filled most densely. Further, when a tertiary sphere is added in addition to the secondary sphere, when the tertiary sphere has a particle size ratio of 0.225 with respect to the primary sphere, the filling rate is 81.0% by volume, which is the most dense. Can be filled. Thus, when filling particles having different particle diameters, the filling ratio can be improved by combining them so as to have a predetermined particle diameter ratio.

(Verification test 3)
Next, the relationship between the filling rate of the magnetic powder and the viscosity of the magnetic powder mixed resin was verified. First, an Fe-6.5% Si powder (average particle diameter D50 = 140 μm) and an epoxy resin prepared by a gas atomization method were prepared. Then, in the magnetic powder mixed resin prepared by dispersing the Fe-6.5% Si powder in the resin, the viscosity was measured by changing the filling rate of the magnetic powder, and the result is shown in FIG. It was.
As shown in FIG. 7, it was confirmed that the viscosity of the magnetic powder mixed resin increased as the filling rate of the magnetic powder increased.

(Verification test 4)
When the viscosity of the magnetic powder mixed resin is increased, the mixing accuracy of the resin and the magnetic powder and the moldability by mold molding are lowered. In particular, when the viscosity exceeds 150 Pa · s, it may be difficult to homogenize the resin and the magnetic powder by kneading, or the moldability during casting may be reduced. From the verification test 3, it was confirmed that the magnetic powder had a viscosity exceeding 150 Pa · s when the filling rate was higher than about 65% by volume, as shown in FIG.
Therefore, as a method of uniformly dispersing the magnetic powder in the resin when the filling rate of the magnetic powder is higher than about 65% by volume, a method of impregnating the resin into the magnetic powder filled in the case was verified.

  First, Fe—Si 6.5% powder (average particle diameter D50 = 140 μm, hereinafter referred to as “iron powder P”) by gas atomization method and Fe—Si 6.5% powder (average particle diameter D50 = 10 μm) by gas atomization method. Hereinafter, “iron powder Q”) was prepared. And both were mixed so that the volume ratio of the iron powder P and the iron powder Q might be set to P: Q = 8: 2, and the magnetic powder composite_body | complex was produced. As shown in FIG. 8, the case 701 was filled with the magnetic powder composite 22a. The case 701 has a circular shape with a diameter of 50 mm and a cylindrical shape with a height of 100 mm with an open top surface.

  Thereafter, the case 701 filled with the magnetic powder composite 22 a was placed in the vacuum chamber 702. Then, the vacuum chamber 702 was depressurized to a vacuum degree of 1000 Pa by a vacuum pump 703. Thereafter, the case 701 was vibrated for a predetermined time at a frequency of 200 Hz by a vibration device (not shown). The vacuum chamber 702 includes a dropping funnel 704 that is connected to the vacuum chamber 702 in a decompressed state so as to be able to drop. With a dropping funnel 704, a predetermined amount of liquid glass resin 23a (viscosity of 10 mPa · s) was poured onto the magnetic powder composite 22a filled in the case 701 in a vacuum chamber 702 under reduced pressure. Thereafter, the inside of the vacuum chamber 702 was returned to atmospheric pressure, the resin surface 23b was pressurized at atmospheric pressure, and the state in which the magnetic powder composite 22a was impregnated with the resin 23a was observed (FIG. 9).

  Then, the impregnation distance (the height of the impregnation layer 802) of the resin 23a is measured every 5 minutes with the measurement start time (0 minute) when the inside of the vacuum chamber 702 is returned to the atmospheric pressure, and the measurement result is shown in FIG. This is shown in FIG. As shown in FIGS. 9 and 10, the resin layer 801 made of the resin 23a is continuously impregnated into the powder layer 803 made of the magnetic powder composite 22a, and is made of the resin 23a and the magnetic powder composite 22a. It was confirmed that the height of the impregnated layer 802 was increased. Then, as shown in FIG. 10, it took 20 minutes for the impregnation distance to be 40 mm. The filling rate of the magnetic powder composite 22a in the impregnated layer 802 was 75.0% by volume.

(Optimization of impregnation speed)
The resin 23a flows through the gap between the magnetic powder composites 22a filled with the case 701 and impregnates the magnetic powder composites 22a. From the hydrodynamic point of view, it is considered that when the magnetic powder is reduced, the gap is also reduced, and the pressure loss in the resin flowing through the gap is increased. Therefore, it can be inferred that the smaller the magnetic powder, the slower the resin flow. Therefore, in order to optimize the impregnation rate by increasing the flow rate of the resin, the relationship between the particle size of the magnetic powder and the pressure loss was verified.

Although the gap of the magnetic powder resin flows is not a circular tube, the characteristic length in the gap, using the equivalent diameter D _R which is defined by the formula shown in Formula 1, in the equivalent diameter D _R of the pressure loss in the gap It was decided to replace the pressure loss of the circular pipe.

As shown in FIG. 11, when the diameter of the magnetic powder 22 is D, the wet wrinkle length l _p is the length of the circumferential surface of the gap q, and the cross-sectional area S of the flow path is the area of the gap q. They are represented by Formula 2 and Formula 3, respectively. Then, the equivalent diameter D _R is with D, it can be expressed by Equation 4 below.

Then, the pressure loss ΔP of Pipe layer flow in equivalent diameter D _R can be the equation of Hagen-Poiseuille, expressed as equation 5 below.

  As shown in Equation 5, the pressure loss of the laminar flow in the circular pipe (that is, the pressure loss of the resin flowing through the gap between the magnetic powders) ΔP is inversely proportional to the square of the diameter D of the magnetic powder. That is, based on this relationship, the pressure loss ΔP in the resin can be adjusted by changing the diameter D (particle diameter) of the magnetic powder.

(Verification test 5)
In order to verify the optimization of the impregnation speed, a composite in which carbon copper spheres having an average particle diameter D50 = 3.0 mm and carbon copper spheres having an average particle diameter D50 = 1.2 mm were mixed at a volume ratio of 8: 2. Prepared and impregnated with resin in the same manner as in verification test 4 above. As shown by the symbol X in FIG. 12, the time required for the impregnation distance to be 40 mm was 10 seconds. Therefore, it was confirmed that by increasing the average particle size of the powder by about 10 times, the impregnation rate of the resin was improved by about 100 times compared to the case of the verification test 2 indicated by the symbol Y in FIG. Thus, it was verified that the impregnation rate of the resin can be optimized by changing the particle size of the magnetic powder.

Based on the said verification test, the effect of the reactor 1 of this example is explained in full detail.
According to the reactor 1 of the present example, in the magnetic powder mixed resin 21, a plurality of magnetic powder aggregates 220 formed by collecting the magnetic powder 22 into a granular shape are dispersed in the insulating resin 23. Since the magnetic powder aggregate 220 has an average particle size larger than that of the magnetic powder 22, the viscosity of the magnetic powder mixed resin 21 is equal to the viscosity of the magnetic powder mixed resin in which the magnetic powder 22 having the same mass as the magnetic powder aggregate 220 is dispersed. Compared to lower. For this reason, it is easy to uniformly disperse the magnetic powder aggregate 220 in the insulating resin 23, so that the filling rate of the magnetic powder 22 in the magnetic powder mixed resin 21 can be easily improved. As a result, the saturation magnetic flux density of the core 20 is improved and the iron loss in the core 20 is reduced, and the entire reactor 1 is reduced in size.

  In the reactor 1 of this example, the plurality of magnetic powder aggregates 220 include a first magnetic powder aggregate 221 having a first average particle diameter (D50 = 3.0 mm) and a first average particle diameter (D50 = 3). And a second magnetic powder aggregate 222 having a second average particle diameter (D50 = 1.2 mm) smaller than 0.0 mm). Thereby, as verified in the verification test 2 described above, in the magnetic powder mixed resin 21, the first magnetic powder aggregate 221 and the second magnetic powder aggregate 222 are more densely packed, and a plurality of magnetic powders are filled. The filling rate of the aggregate 220 is further improved.

  In the reactor 1 of this example, the plurality of magnetic powder aggregates 220 include a first magnetic powder aggregate 221 having a first average particle diameter (D50 = 3.0 mm) and a second average particle diameter (D50 = 1). In addition to the second magnetic powder aggregate 222 having a second average particle size (D50 = 1.2 mm) and a third average particle size (D50 = 0.6 mm). It has a magnetic powder aggregate 223. Thereby, as described in the verification test 2 described above, the first magnetic powder aggregate 221, the second magnetic powder aggregate 222, and the third magnetic powder aggregate 223 are more densely filled in the magnetic powder mixed resin 21. As a result, the filling rate of the plurality of magnetic powder aggregates 220 is further improved.

  In the reactor 1 of this example, as shown in FIG. 4, in the magnetic powder mixed resin 21, the insulating resin 23 disperses and encloses the magnetic powder 22 together with the magnetic powder aggregate 220. Thereby, in the magnetic powder mixed resin 21, the magnetic powder 22 enters the gap between the magnetic powder aggregates 220, and the filling rate of the magnetic powder aggregates 220 including the magnetic powder 22 is further improved.

  In this example, since the magnetic powder 22 has an insulating coating, the insulation between the magnetic powders 22 is maintained in the magnetic powder aggregate 220. Thereby, an increase in eddy current loss due to the formation of a granular magnetic powder aggregate 23 larger than the individual magnetic powder 22 by compressing the magnetic powder 22 is prevented. Accordingly, by appropriately adjusting the particle size of the magnetic powder aggregate 220 (the first magnetic powder aggregate 221, the second magnetic powder aggregate 222, and the third magnetic powder aggregate 223) obtained by compressing the magnetic powder 22. The impregnation speed of the insulating resin 23 can be optimized without increasing the eddy current loss.

  In this example, in the assembly forming step, the magnetic powder assembly 220 includes a first magnetic powder assembly 221 and a second magnetic powder assembly 222, and after the assembly forming step, and Prior to the assembly arrangement step, an assembly mixing step of mixing the first magnetic powder assembly 221 and the second magnetic powder assembly 222 is included. As a result, in the magnetic powder aggregate 220, the first magnetic powder aggregate 221 and the second magnetic powder aggregate 222 are sufficiently mixed. In the magnetic powder mixed resin 21, both of them are uniformly in the insulating resin 23. This contributes to an improvement in the filling rate. In this example, the magnetic powder aggregate 220 further includes a third magnetic powder aggregate 223, and the third magnetic powder aggregate 223 is also the first magnetic powder aggregate 221 and the second magnetic powder aggregate 222. In the same manner as above, the mixture is sufficiently mixed in the assembly mixing step, and is uniformly dispersed in the insulating resin 23 in the assembly formation step.

  In the resin mixing step, the magnetic powder mixed resin 21 was formed by impregnating the magnetic powder aggregate 220 disposed in the case 30 with the insulating resin 23. As a result, as shown in the verification test 5, the magnetic powder aggregate 220 is easily and uniformly dispersed in the insulating resin 23 even in the magnetic powder mixed resin 21 of this example having a high filling rate of the magnetic powder aggregate 220. be able to.

  In this example, in the mixing step, the magnetic powder aggregate 220 (magnetic powder 22) is uniformly dispersed in the insulating resin 23 by impregnating the plurality of magnetic powder aggregates 220 arranged in the case with the insulating resin 23. . However, in the mixing step, when the required mixing accuracy and moldability in mold forming can be obtained, the insulating resin 23 and the magnetic powder aggregate 220 are mixed uniformly by kneading instead of or together with the impregnation. It may be dispersed.

  In this example, an annealing process was performed after the assembly creating process and before the assembly mixing process. Thereby, in the said assembly preparation process, the internal residual stress and the residual distortion of the magnetic powder aggregate 220 are removed, the hysteresis loss in the core 20 can be reduced, and the iron loss can be reduced. If it is not necessary to remove the internal residual stress and residual strain of the magnetic powder aggregate 220, the annealing process can be omitted, and the manufacturing process can be simplified.

  In this example, the magnetic powder aggregate 220 includes the second magnetic powder aggregate 222 and the third magnetic powder aggregate 223 in addition to the first magnetic powder aggregate 221. The aggregate 222 and the third magnetic powder aggregate 223 may not be included. Even in this case, the operational effects of this example can be achieved except for the operational effects of the magnetic powder aggregate 220 including the second magnetic powder aggregate 222 and the third magnetic powder aggregate 223. If the second magnetic powder assembly 222 and the third magnetic powder assembly 223 are not included, the assembly mixing step of mixing the magnetic powder assembly 220 by the blender 403 can be omitted, and the manufacturing process can be omitted. It can be simplified.

DESCRIPTION OF SYMBOLS 1 Reactor 10 Coil 20 Core 21 Magnetic powder mixed resin 22 Magnetic powder 220 Magnetic powder aggregate 221 First magnetic powder aggregate 222 Second magnetic powder aggregate 223 Third magnetic powder aggregate 23 Insulating resin 30 Case

Claims (7)

A coil (10) that generates magnetic flux when energized;
A core (20) obtained by curing the magnetic powder mixed resin (21) and having the coil (10) embedded therein;
With
The magnetic powder mixed resin (21) is a state in which a plurality of magnetic powder aggregates (220) formed by agglomerating the magnetic powder (22) into a granular form and the plurality of magnetic powder aggregates (220) are dispersed. And a reactor (1) having an insulating resin (23) encapsulated therein.   The plurality of magnetic powder aggregates (220) includes a first magnetic powder aggregate (221) having a first average particle diameter and a second average particle diameter smaller than the first average particle diameter. Reactor (1) according to claim 1, characterized in that it has two magnetic powder aggregates (222).   In the magnetic powder mixed resin (21), the insulating resin (23) includes the magnetic powder (22) dispersed and encapsulated together with the magnetic powder aggregate (220). 2. The reactor (1) according to 2.   The reactor (1) according to any one of claims 1 to 3, wherein the magnetic powder (22) has an insulating coating (24). An assembly forming step of assembling the magnetic powder (22) to form a plurality of granular magnetic powder assemblies (220);
A coil placing step of placing the coil (10) that generates magnetic flux when energized in the case (30);
An assembly arrangement step of arranging the plurality of magnetic powder assemblies (220) in the case (30) on which the coil (10) is placed;
A liquid insulating resin (23) is poured into the case (30) in which the plurality of magnetic powder aggregates (220) are arranged, and the plurality of magnetic powder aggregates (220) are dispersed in the insulating resin (23). A mixed resin forming step of forming a magnetic powder mixed resin (21),
A curing step of curing the magnetic powder mixed resin (21) formed in the mixing step;
The manufacturing method of the reactor (1) characterized by including these.   In the aggregate formation step, the magnetic powder aggregate (220) includes a first magnetic powder aggregate (221) having a first average particle diameter and a second average smaller than the first average particle diameter. A second magnetic powder aggregate (222) having a particle size, and after the aggregate formation step and before the aggregate arrangement step, the first magnetic powder aggregate (221) and the second magnetic powder aggregate (222). The manufacturing method of the reactor (1) according to claim 5, further comprising an assembly mixing step of mixing the two magnetic powder assemblies and (222).   In the resin mixing step, the magnetic powder mixed resin (21) is formed by impregnating the magnetic powder aggregate (220) disposed in the case (30) with the insulating resin (23). The manufacturing method of the reactor (1) of Claim 5 or 6.