Multilayer magnets and motors

Abstract

This invention provides a technology to improve the residual magnetic flux density in stacked magnets. [Solution] The stacked magnet comprises a plurality of stacked magnets, an intermediate layer having an insulating portion formed of an insulating material and a magnetic portion formed of a magnetic material, and the intermediate layer being disposed between adjacent magnets among the plurality of magnets.

Description

Technical Field

[0001] The present invention relates to a laminated magnet and a motor.

Background Art

[0002] Conventionally, a laminated magnet in which a plurality of magnets are laminated has been known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even with the prior art such as Patent Document 1, there is still room for improvement in the technology for improving the residual magnetic flux density in the laminated magnet.

[0005] An object of the present invention is to provide a technology for improving the residual magnetic flux density in a laminated magnet.

Means for Solving the Problems

[0006] The present invention has been made to solve at least part of the above problems and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, a laminated magnet is provided. This laminated magnet is an intermediate layer having a plurality of laminated magnets, an insulating portion formed of an insulating material, and a magnetic portion formed of a magnetic material, and is an intermediate layer disposed between adjacent magnets among the plurality of magnets.

[0008] In this configuration, the intermediate layer placed between adjacent magnets has an insulating portion made of an insulating material and a magnetic portion made of a magnetic material. As a result, since magnetic material is also present in the region that insulates adjacent magnets, the proportion of magnetic material in the entire laminated magnet can be increased compared to when the intermediate layer is made of an insulating material. Therefore, the residual magnetic flux density can be improved.

[0009] (2) In the stacked magnet of the above form, the ratio of the area of ​​the magnetic part to the area of ​​the intermediate layer in a cross-section in the stacking direction of the plurality of magnets may be 50% or more and 60% or less. With this configuration, the ratio of the area of ​​the magnetic part to the area of ​​the intermediate layer in a cross-section in the stacking direction of the plurality of magnets is 50% or more and 60% or less. As a result, the thermal conductivity of the intermediate layer is improved compared to when it is formed of an insulating material, so that the heat generated in the magnet can be easily transferred through the magnetic part. Therefore, the temperature rise of the stacked magnet can be suppressed.

[0010] (3) In the laminated magnet of the above form, the magnetic portion may be in contact with each of the adjacent magnets. With this configuration, the magnetic portion of the intermediate layer is in contact with each of the adjacent magnets. This makes it easier for the heat generated in the magnets to be transferred further through the magnetic portion. Therefore, the temperature rise of the laminated magnet can be further suppressed.

[0011] (4) In the laminated magnet of the above form, the magnetic portion may be made of the same type of magnetic material as the material that forms each of the plurality of magnets. With this configuration, the magnetic portion of the intermediate layer is made of the same type of magnetic material as the material that forms each of the plurality of magnets. As a result, the magnetic portion and the magnet become integrated and the bonding strength between the magnetic portion and the magnet increases, thereby improving the strength of the laminated magnet.

[0012] (5) In the stacked magnet of the above form, the magnetic part does not have to be in contact with each of the adjacent magnets. With this configuration, since the magnetic part is not in contact with each of the adjacent magnets, it is possible to suppress the flow of eddy currents generated in each of the multiple magnets in the other magnets. Therefore, it is possible to suppress an increase in eddy current loss.

[0013] (6) According to another embodiment of the present invention, a motor is provided. This motor comprises a rotor having the above-described laminated magnet and a stator having coils. In this configuration, the rotor of the motor has a laminated magnet having an intermediate layer having an insulating portion formed of an insulating material and a magnetic portion formed of a magnetic material. This makes it possible to improve the residual magnetic flux density of the laminated magnet, and thus the output of the motor can be made relatively large.

[0014] Furthermore, the present invention can be realized in various forms, for example, in the form of a method for manufacturing a laminated magnet, a method for manufacturing an intermediate layer of a laminated magnet, an apparatus including a laminated magnet, a method for manufacturing an apparatus including a laminated magnet, and a method for controlling an apparatus including a laminated magnet. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view of the laminated magnet according to the first embodiment. [Figure 2] This is a cross-sectional view of the stacked magnet according to the first embodiment. [Figure 3] This is a cross-sectional view of a motor equipped with a stacked magnet according to the first embodiment. [Figure 4] This is a cross-sectional view of a rotor equipped with a stacked magnet according to the first embodiment. [Figure 5] This is an enlarged cross-sectional view of the stacked magnet of the first embodiment. [Figure 6] This is the first figure illustrating the results of an evaluation test of a stacked magnet according to the first embodiment. [Figure 7] This is the second figure illustrating the results of an evaluation test of the stacked magnet according to the first embodiment. [Figure 8]It is an enlarged cross-sectional view of the laminated magnet of the second embodiment. [Figure 9] It is a perspective view of a modified example of the laminated magnet of the first embodiment.

Mode for Carrying Out the Invention

[0016] <First Embodiment> FIG. 1 is a perspective view of the laminated magnet 10 of the present embodiment. FIG. 2 is a cross-sectional view of the laminated magnet 10 of the present embodiment. FIG. 3 is a cross-sectional view of the motor 100 including the laminated magnet 10 of the present embodiment. FIG. 4 is a cross-sectional view of the rotor 110 including the laminated magnet 10 of the present embodiment. The laminated magnet 10 of the present embodiment is used in a motor 100 that generates rotational torque by electricity supplied from an external power source not shown in the figure. As shown in FIG. 1, the laminated magnet 10 includes a plurality of magnets 11 that are laminated and an intermediate layer 12. Note that the technical field in which the laminated magnet 10 of the present embodiment is used is not limited to motors.

[0017] The motor 100 of the present embodiment includes a rotor 110, a stator 120, and a motor case 130. The rotor 110 includes a rotor member 110a having a substantially cylindrical shape and a laminated magnet 10. In the motor 100 of the present embodiment, the laminated magnet 10 is provided on the rotor 110 such that the lamination direction of the plurality of magnets 11 and the intermediate layer 12 in the laminated magnet 10 is parallel to the rotation axis C1 of the rotor 110 in the motor 100 (see FIG. 3). The laminated magnet 10 is inserted into an insertion hole 110b formed in the rotor 110.

[0018] Magnet 11 contains rare earth elements. Examples of rare earth elements include one or more selected from the group consisting of neodymium (Nd), praseodymium (Pr), terbium (Tb), dysprosium (Dy), samarium (Sm), yttrium (Y), scandium (Sc), lanthanum (La), cerium (Ce), europium (Eu), gadolinium (Gd), holmium (Ho), ytterbium (Yb), and lutetium (Lu). Among these, it is desirable that the magnet contains one or more of Nd, Pr, Dy, and Tb as rare earth elements, and it is more desirable that it contains Nd as the main component. Note that "containing Nd as the main component" means that the Nd content (mass%) is the highest among the rare earth elements contained in magnet 11. In addition to rare earth elements, magnet 11 may also contain transition metal elements and boron. In the stacked magnet 10 of this embodiment, multiple magnets 11 are stacked with an intermediate layer 12 in between. The magnetization directions of each of the multiple magnets 11 are arranged parallel to each other, for example, in the x-axis direction in the perspective view of the stacked magnet 10 shown in Figure 1.

[0019] The intermediate layer 12 is placed between adjacent magnets 11 among the multiple magnets 11. The intermediate layer 12 has an insulating portion formed of an insulating material and a magnetic portion formed of a magnetic material.

[0020] Figure 5 is an enlarged cross-sectional view of the laminated magnet 10 of this embodiment. Figure 5 is an enlarged cross-sectional view of the portion of the cross-sectional view of the laminated magnet 10 shown in Figure 2 that includes the intermediate layer 12. As shown in Figure 5, the intermediate layer 12 has an insulating portion 121 formed of an insulating material and a magnetic portion 122 formed of a magnetic material. The film thickness d12 of the intermediate layer 12 in this embodiment is 10 μm. It is desirable that the film thickness d12 of the intermediate layer 12 be 30 μm or less. The film thickness d12 of the intermediate layer can be, for example, 1 μm or more.

[0021] The insulating portion 121 is formed of an insulating material. In this embodiment, the insulating portion 121 is formed of ceramics. It is desirable that the insulating portion 121 contains one or more selected from the group consisting of CaF2, BaF2, SrF2, MgF2, Al2O3, ZrO2, Dy2O3, Tb2O3, Nd2O3, TbF3, DyF3, LiF, SiO2, BN, ZrB2, Si3N4, TiB2, Pr2O3, and SiC. It is desirable that the insulating portion 121 contains at least a fluoride of Group IIA of the periodic table. It is even more desirable that the insulating portion 121 contains at least one fluoride of Group IIA of the periodic table selected from the group consisting of CaF2, BaF2, SrF2, and MgF2. In this embodiment, the insulating portion 121 contains CaF2.

[0022] The magnetic portion 122 is in contact with each of the adjacent magnets 11. In this embodiment, the magnetic portion 122 is made of the same type of magnetic material as the material that forms each of the multiple magnets 11. Therefore, in this embodiment, the boundary between the magnet 11 and the intermediate layer 12 is defined in the following way. For the insulating portion 121 included in the cross-section shown in Figure 5, the position on the most positive side in the z-axis direction (stacking direction) is defined as position P1, and the position on the most negative side in the z-axis direction is defined as position P2. The region between the imaginary line B1 passing through position P1 and parallel to the x-axis and the imaginary line B2 passing through position P2 and parallel to the x-axis is defined as the intermediate layer 12 of the stacked magnet 10 of this embodiment.

[0023] In the stacked magnet 10 of this embodiment, in a cross-section in the stacking direction of the multiple magnets 11 as shown in Figure 5, the ratio of the area of ​​the magnetic part 122 to the area of ​​the intermediate layer 12 is 50% or more and 60% or less. That is, the ratio Ra(%) of the area of ​​the magnetic part 122 to the area of ​​the intermediate layer 12 in a cross-section in the stacking direction of the multiple magnets 11 is calculated by the following formula (1), where the area of ​​the intermediate layer 12 included in the cross-section in the stacking direction of the multiple magnets 11 is area S12, and the area of ​​the magnetic part 122 included in the cross-section in the stacking direction of the multiple magnets 11 is area S122. In Figure 5, the ratio of the area of ​​the magnetic part 122 to the area of ​​the intermediate layer 12 is 51.7%. The area S12 of the intermediate layer 12 and the area S122 of the magnetic part 122 can be calculated by performing image processing on a cross-sectional image of the stacked magnet 10 (magnification: 2000x) taken using a scanning electron microscope (SEM), binarizing the regions corresponding to the insulating part 121 and the magnetic part 122 contained in the intermediate layer 12, and calculating their areas. Ra = S12² / S12 × 100 ... (1)

[0024] The stator 120 has a stator core 120a and a coil 120b. The stator 120 is located outside the rotor 110 and is fixed to the motor case 130 inside the motor case 130, which will be described later. The stator core 120a is formed to have a substantially cylindrical shape and has a plurality of protrusions 120c on its inside. The coil 120b is a conductive wire covered with an insulator and is wound around each of the plurality of protrusions 120c on the stator core 120a. When electricity supplied from outside the motor 100 flows through the coil 120b, it generates a magnetic field.

[0025] The motor case 130 is a hollow component that houses the rotor 110 and the stator 120 inside. The motor case 130 is provided with two bearings 130a and 130b. Each of the two bearings 130a and 130b rotatably supports the rotor 110.

[0026] Next, the manufacturing method of the stacked magnet 10 of this embodiment will be described. In the manufacturing of the stacked magnet 10, first, a strip-cast alloy (SC alloy) powder is prepared (preparation step). In this embodiment, the composition of the SC alloy is Nd2Fe 14 This is represented by B. SC alloys are prepared by mixing the main raw materials of Nd / Pr alloys, alloys containing Co, Al, Cu, Ga, and Zr, and elemental metals, under an argon atmosphere. Next, the SC alloy is subjected to hydrogen absorption using a hydrogen furnace (hydrogen atmosphere, temperature: 200°C, time: 2 hours) to embrittle the grain boundaries (neodymium-rich phase) of the SC alloy (hydrogen decomposition process), thereby producing SC alloy powder.

[0027] Following the hydrogenation process, a lubricant is added to the SC alloy powder (first lubricant addition step). Methyl caprylate is used as the lubricant. The mixing ratio of the lubricant to the amount of SC alloy is, for example, 0.03% to 0.07% by mass. Specifically, the SC alloy powder is coarsely ground under a nitrogen or argon atmosphere while adding the lubricant using a stirrer (coarse grinding step). The average particle size D50 of the SC alloy powder after coarse grinding is, for example, 50 μm to 500 μm.

[0028] Following the coarse grinding process, the coarsely ground SC alloy powder is finely ground using a jet mill under a nitrogen atmosphere while adding a lubricant (fine grinding process). The average particle size D50 after fine grinding is, for example, 2.0 μm to 3.5 μm. Next, a lubricant is added to the finely ground SC alloy powder (second lubricant addition process). Methyl laurate is used as the lubricant. The mixing ratio of the lubricant to the amount of SC alloy is, for example, 0.05 mass% to 0.1 mass%.

[0029] Following the second lubricant addition step, SC alloy powder is filled into each of the multiple molding spaces of a mold equipped with multiple partition plates in a nitrogen atmosphere (powder filling step). Each of the multiple molded bodies formed in each of the multiple molding spaces corresponds to the magnets that will be stacked in the temporary fixing step described later. After the powder filling step, an external magnetic field of, for example, 2T to 4T (Tesla) is applied to the mold filled with SC alloy powder in the planar direction (perpendicular to the thickness direction) of each of the multiple molded bodies to align the orientation of the SC alloy powder (orientation step). Next, the SC alloy powder filled in the mold is pressurized to form the SC alloy molded body (molding step). The conditions for pressurized molding in the molding step are, for example, a pressure of 5MPa to 20MPa and a filling density of 3.0g / cm³. 3 ~4.0g / cm 3 The relative density is 40% to 52%.

[0030] Following the molding process, the outer frame is removed from the mold, and the fired product, in which the molded body and partition plates are alternately connected, is removed (removal process). The fired product, including the partition plates, is heated in an argon atmosphere at a temperature of 500°C for 3 to 4 hours to dehydrogenate it. The dehydrogenated fired product, including the partition plates, is held at a temperature of 930°C to 1050°C for 3 hours and fired in a vacuum atmosphere (first firing process). This produces the magnet 11.

[0031] Following the first firing process, the partition plate is removed from the manufactured magnet 11, and the raw material for the insulating layer 121 is applied to the surface of the magnet 11 before lamination (intermediate layer coating process). A mixture of CaF2 powder and a solvent is used as the raw material for the insulating layer 121. The coating thickness of the insulating layer 121 raw material applied to the surface of the magnet 11 before lamination is 20 μm, which is twice the thickness of the intermediate layer 12 in the laminated magnet 10 (10 μm). The coating of the insulating layer 121 raw material is performed in the atmosphere, for example, by spraying. However, the method of applying the insulating layer 121 raw material to the surface of the magnet 11 is not limited to this.

[0032] Following the intermediate layer coating process, multiple magnets 11 coated with the insulating material 121 are stacked in the atmosphere and temporarily fixed (temporary fixing process). Following the temporary fixing process, the temporarily fixed stack is placed in a hot press mold and subjected to uniaxial hot pressing (hot pressing process). In the hot pressing process, for example, a pressure of 5 × 10 -2 Pa~1×10 -4 The process is carried out under a vacuum atmosphere of approximately Pa, or under an inert atmosphere (such as a nitrogen or argon atmosphere). The hot press temperature is, for example, 700°C to 1100°C, and the hot press press duration is, for example, 1 second to 1 hour. The hot press pressure is, for example, 3 MPa to 100 MPa, and the hot press heat treatment duration is, for example, 3 minutes to 20 hours. In the manufacturing method of the laminated magnet 10 of this embodiment, during such a hot press process, the magnetic material forming the magnet 11 diffuses into the raw material of the insulating part 121, and the magnetic part 122 is formed. The laminated magnet 10 of this embodiment is manufactured in this manner. However, the manufacturing method of the laminated magnet 10 is not limited to this.

[0033] Next, the evaluation test of the laminated magnet in this embodiment will be described. In this evaluation test, multiple laminated magnets with different intermediate layer thicknesses (hereinafter referred to as "samples") were prepared, and the "eddy current loss ratio," "residual magnetic flux density," and "motor magnet temperature" were measured or calculated for each of the multiple samples.

[0034] Figure 6 is the first diagram illustrating the evaluation results of the laminated magnet of this embodiment. The five types of samples used in this evaluation test were manufactured by a method similar to the manufacturing method of the laminated magnet 10 of this embodiment. Sample 1 is a comparative example sample in this evaluation test and does not have a portion corresponding to the intermediate layer of this embodiment, and has a structure in which multiple magnets are simply stacked. Each of Samples 2 to 4 has an intermediate layer having an insulating portion formed of an insulating material and a magnetic portion formed of a magnetic material, similar to the laminated magnet 10 of this embodiment. The insulating portion of each of Samples 2 to 4 contains CaF2, and the magnetic portion is formed of the same material as the magnet. In Sample 5, the portion corresponding to the intermediate layer of this embodiment is composed only of an insulating portion. The size of the magnets in the samples used in this evaluation test is 6 mm in the magnetization direction × 2 mm × 20 mm in the stacking direction, and the size of the portion of the laminated magnet excluding the intermediate layer is 6 mm in the magnetization direction × 40 mm × 20 mm in the stacking direction.

[0035] The "intermediate layer thickness (μm)" shown in Figure 6 was calculated from the thickness of the insulating material applied during the intermediate layer coating process in the preparation of Samples 1 to 5. Specifically, the intermediate layer thickness in each sample was calculated based on measured data where the thickness of the insulating material applied during the intermediate layer coating process was reduced to 0.5 times by hot pressing. Each of Samples 2 to 5, which have an intermediate layer, contains CaF2, a ceramic, as the "insulating material," as described above.

[0036] Figure 6 shows the ratio of the area of ​​the magnetic portion to the area of ​​the intermediate layer in a cross-section in the stacking direction of the multiple magnets for each of Samples 2 to 5, expressed as "Percentage occupied by the magnetic portion (%)". The method for calculating "Percentage occupied by the magnetic portion (%)" is the same as the method for calculating the ratio Ra (%) of the area of ​​the magnetic portion 122 to the area S12 of the intermediate layer 12 in the stacked magnet 10 of this embodiment (see Equation (1)). As mentioned above, Sample 1 does not have an intermediate layer. In Samples 2 to 5, the "Percentage occupied by the magnetic portion (%)" decreases in the order of Sample 2, Sample 3, and Sample 4, and in Sample 5, it is 0% because the intermediate layer is formed of an insulating material.

[0037] The "Eddy Current Loss Ratio (%)" shown in Figure 6 represents a comparison of the eddy current losses for each of the samples from Sample 1 to Sample 5. Here, we will explain how the "Eddy Current Loss Ratio (%)" shown in Figure 6 was calculated. First, each of the samples from Sample 1 to Sample 5 was placed between the magnetic poles of a C-type core, and the eddy current loss was measured using a power meter under conditions of 25°C, 500Hz, and a magnetic flux density of 0.01T. Next, using the measured eddy current losses for each of the samples from Sample 1 to Sample 5, the ratio of the measured eddy current losses for each of the samples from Sample 2 to Sample 5 was calculated, with the measured eddy current loss for Sample 1 set to 100. As shown in Figure 6, the "Eddy Current Loss Ratio (%)" for all of the samples from Sample 2 to Sample 5 is smaller than that for Sample 1.

[0038] The "Residual Magnetic Flux Density (T)" shown in Figure 6 represents a comparison of the residual magnetic flux densities for each of the samples from 1 to 5. Here, we will explain the method for calculating the "Residual Magnetic Flux Density (T)" shown in Figure 6. In this method, the residual magnetic flux densities of sample 1, with an intermediate layer thickness of 0 μm, and sample 5, with an intermediate layer thickness of 25.0 μm, were measured using a Teslameter (Gaussmeter). Next, for each of the samples from 2 to 4, whose intermediate layer thicknesses fall within the range of 0 μm to 25.0 μm, the residual magnetic flux densities for each of the samples from 2 to 4 were calculated using the one-to-one correspondence between the intermediate layer thickness and the residual magnetic flux density. In this evaluation test, the "Residual Magnetic Flux Density (T)" scores were set as follows, according to the magnitude of the calculated (measured) values ​​of the residual magnetic flux density. 1.40T: 5 points 1.38T or more and less than 1.40T: 3 points 1.37T or higher and less than 1.38T: 1 point Less than 1.37T: 0 points

[0039] Figure 6 shows the "Motor Magnet Temperature (°C)" for Sample 1 and Sample 5, respectively, representing the calculated (measured) temperature of the samples when used as motor magnets under the same conditions. Here, we will explain the method (measurement method) for calculating the "Motor Magnet Temperature (°C)" shown in Figure 6. In the method (measurement method) for calculating the "Motor Magnet Temperature (°C)," first, a motor with Sample 1 (eddy current loss ratio of 100%) and Sample 5 (eddy current loss ratio of 73%) set on its rotor was driven for 200 hours at a maximum torque of 500 N·m and a maximum rotational speed of 10,000 rpm. After that, the surface temperature of the samples was measured by observing the surface of the samples with a laser. Next, for each of Samples 2 to 4, whose eddy current loss ratios fall within the range of 73% to 100%, the motor magnet temperature of each of Samples 2 to 4 was calculated using the one-to-one correspondence between the eddy current loss ratio and the motor magnet temperature. In this evaluation test, for each of Samples 1 to 5, the score for "Motor Magnet Temperature (°C)" was set as follows, according to the magnitude of the calculated (measured) value of "Motor Magnet Temperature (°C)". Note that the score for "Motor Magnet Temperature (°C)", which is intended for use in motors, the primary application of multilayer magnets, is set higher than the score for "Residual Magnetic Flux Density (T)" mentioned above. Below 60℃: 8 points 60℃ or higher but less than 70℃: 5 points 70°C to less than 75°C: 3 points 75℃ or higher: 0 points

[0040] The "Overall Evaluation" shown in Figure 6 was determined for each of Samples 2 to 5 using the sum of the scores for "Residual Magnetic Flux Density (T)" and "Motor Magnet Temperature (°C)". In this evaluation test, for each of Samples 2 to 5, the "Overall Evaluation" was grouped according to the magnitude of the sum of the scores for "Residual Magnetic Flux Density (T)" and "Motor Magnet Temperature (°C)", as follows. The total score for Sample 1, which is a comparative example, is 5 points. If either the score for "Residual Magnetic Flux Density (T)" or the score for "Motor Magnet Temperature (°C)" is 0, the "Overall Evaluation" was set to "C". 8 points or more:A 6 points or more and 7 points or less: B 5 points or less: C

[0041] From the "Remanent Magnetic Flux Density (T)" shown in Figure 6, it was confirmed that the "Percentage Occupied by Magnetic Parts (%)" for Sample 2 (79.12%), Sample 3 (59.00%), and Sample 4 (51.70%) were all larger than that of Sample 5, where the "Percentage Occupied by Magnetic Parts (%)" was 0%, meaning the portion corresponding to the intermediate layer consisted solely of insulating material. Furthermore, the difference between the remanent magnetic flux density of Samples 2 to 4 and that of Sample 1, which has no portion corresponding to an intermediate layer, was within the tolerance range of ±0.03(T) of the Teslameter used for measurement. This confirmed that the remanent magnetic flux densities of Samples 2 to 4 were approximately the same as those of Sample 1.

[0042] As shown in Figure 6, the "Motor Magnet Temperature (°C)" for each of the samples from 2 to 4 was found to be lower than that of sample 1. In particular, the "Motor Magnet Temperature (°C)" was found to be significantly lower for sample 3 (59.0%) and sample 4 (51.7%) than that of sample 1. These results suggest that when the ratio of the magnetic area to the area of ​​the intermediate layer is between 50% and 60%, the temperature of the laminated magnet used in a motor decreases significantly.

[0043] As shown in the "Overall Evaluation" in Figure 6, it was confirmed that each of Samples 2 to 4 exhibited superior characteristics compared to the comparative examples Sample 1 and Sample 5. Therefore, when the laminated magnets of Samples 2 to 4 are used in a motor, the residual magnetic flux density is improved compared to when the laminated magnet of Sample 5, which has an intermediate layer formed of insulating material, thus allowing for a higher motor output. Among Samples 2 to 4, Samples 3 and 4 were found to exhibit a significant decrease in motor magnet temperature while maintaining almost no change in residual magnetic flux density compared to Sample 1. Therefore, when the laminated magnets of Samples 3 and 4 are used in a motor, the motor temperature rise can be suppressed, allowing for an even higher motor output.

[0044] Figure 7 is a second figure illustrating the results of the evaluation test of the stacked magnet of the first embodiment. Figure 7 shows the relationship between the thickness of the intermediate layer and the eddy current loss ratio for each of several samples, including samples 1 to 5 shown in Figure 6. In Figure 7, similar to the "eddy current loss ratio (%)" shown in Figure 6, the eddy current loss in sample 1, where the intermediate layer thickness is 0 μm, i.e., sample 1 has no intermediate layer, is set to 100%, and the "eddy current loss ratio (%)" for several samples is shown. As shown in Figure 7, it was confirmed that the eddy current loss ratio of the samples decreases as the thickness of the intermediate layer increases, and it was confirmed that even with an intermediate layer thickness of 30 μm, the eddy current loss ratio is smaller than that of sample 1. From this, it can be said that, in terms of reducing eddy current loss, it is desirable for the thickness of the intermediate layer to be 30 μm or less.

[0045] As shown in Figure 7, the eddy current loss ratio of the sample gradually decreases until the intermediate layer thickness reaches approximately 10 μm, but it was confirmed that the eddy current loss ratio does not change significantly even when the intermediate layer thickness exceeds 10 μm. In terms of improving the residual magnetic flux density in a laminated magnet, it is desirable for the proportion of the volume of the laminated magnet to be occupied by the magnet and magnetic parts formed by the magnetic material to be large. Therefore, in terms of reducing eddy current loss, it is more desirable for the intermediate layer thickness to be 10 μm or less.

[0046] As described above, in the laminated magnet 10 of this embodiment, the intermediate layer 12, which is placed between adjacent magnets 11 among the multiple magnets 11, has an insulating portion 121 formed of an insulating material and a magnetic portion 122 formed of a magnetic material. As a result, since magnetic material is also present in the region for insulating adjacent magnets 11, the proportion of magnetic material in the entire laminated magnet can be increased compared to when the intermediate layer 12 is formed of an insulating material. Therefore, the residual magnetic flux density in the laminated magnet 10 can be improved.

[0047] Furthermore, in the stacked magnet 10 of this embodiment, in the cross-section in the stacking direction of the multiple magnets 11, the ratio of the area S122 of the magnetic portion 122 to the area S12 of the intermediate layer 12 is 50% or more and 60% or less. As a result, the thermal conductivity of the intermediate layer 12 is improved compared to when it is formed of an insulating material, so that the heat generated in the magnet 11 can be easily transferred through the magnetic portion 122. Therefore, the temperature rise of the stacked magnet 10 can be suppressed.

[0048] Furthermore, in the laminated magnet 10 of this embodiment, the magnetic portion 122 of the intermediate layer 12 is in contact with each of the adjacent magnets 11. This makes it easier for the heat generated in the magnets 11 to transfer through the magnetic portion 122. Therefore, the temperature rise of the laminated magnet 10 can be further suppressed.

[0049] Furthermore, in the laminated magnet 10 of this embodiment, the magnetic portion 122 of the intermediate layer 12 is made of the same type of magnetic material as the material that forms each of the multiple magnets 11. As a result, the magnetic portion 122 and the magnets 11 are integrated, and the bonding strength between the magnetic portion 122 and the magnets 11 is increased, thereby improving the strength of the laminated magnet 10.

[0050] Furthermore, according to the motor 100 of this embodiment, the rotor 110 of the motor 100 has a laminated magnet 10 that includes an intermediate layer 12 having an insulating portion 121 formed of an insulating material and a magnetic portion 122 formed of a magnetic material. This makes it possible to improve the residual magnetic flux density of the laminated magnet 10, and thus the output of the motor 100 can be made relatively large.

[0051] <Second Embodiment> Figure 8 is a cross-sectional view of the stacked magnet 20 of the second embodiment. Compared with the stacked magnet 10 of the first embodiment (Figure 1), the stacked magnet 20 of the second embodiment has a different positional relationship between the insulating portion and the magnetic portion in the intermediate layer.

[0052] The stacked magnet 20 of this embodiment comprises a plurality of stacked magnets 11 and an intermediate layer 22. The intermediate layer 22 is positioned between adjacent magnets 11 among the plurality of magnets 11. The intermediate layer 22 has an insulating portion 221 formed of an insulating material and a magnetic portion 222 formed of a magnetic material. In the intermediate layer 22 of the stacked magnet 20, the magnetic portion 222 is not in contact with each of the adjacent magnets 11. This makes it possible to suppress eddy currents generated in the magnets 11 from flowing into the adjacent magnets 11 via the magnetic portion 222.

[0053] As described above, in the laminated magnet 20 of this embodiment, the intermediate layer 22, which is placed between adjacent magnets 11 among the plurality of magnets 11, has an insulating portion 221 made of an insulating material and a magnetic portion 222 made of a magnetic material. This makes it possible to increase the proportion of magnetic material in the entire laminated magnet, and thus improve the residual magnetic flux density in the laminated magnet 20.

[0054] Furthermore, in the stacked magnet 20 of this embodiment, since the magnetic portion 222 is not in contact with each of the adjacent magnets, it is possible to suppress the flow of eddy currents generated in each of the multiple magnets 11 into the other magnets 11. Therefore, it is possible to suppress an increase in eddy current loss in the stacked magnet 20.

[0055] <Modified form of this embodiment> The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit, for example, the following modifications are also possible.

[0056] [Example 1] In the above embodiment, the ratio of the area of ​​the magnetic portion 122 to the area of ​​the intermediate layer 12 in a cross-section in the stacking direction of the multiple magnets 11 was set to 50% or more and 60% or less. The ratio of the area of ​​the magnetic portion 122 to the area of ​​the intermediate layer 12 is not limited to this. The ratio of the area of ​​the magnetic portion to the area of ​​the intermediate layer may be less than 50% or greater than 60%. By setting the ratio of the area of ​​the magnetic portion to the area of ​​the intermediate layer to 50% or more and 60% or less, it is possible to achieve a reasonable balance between improving the residual magnetic flux density and lowering the motor magnet temperature.

[0057] [Differentiation 2] In the embodiment described above, the magnetic portion is formed from the same type of magnetic material as the material forming each of the multiple magnets. However, the material forming the magnetic portion is not limited to this; it just needs to be a magnetic material.

[0058] [Difference 3] In the embodiment described above, the stacked magnet was assumed to be rectangular in shape, as shown in Figure 1. However, the shape of the stacked magnet is not limited to this.

[0059] Figure 9 is a perspective view of a modified example of the laminated magnet 10 of the first embodiment. The laminated magnet 10 shown in Figure 9 has a shape when viewed from the z-axis direction that is the unfolded side of a frustocone. Even in a laminated magnet 10 of this shape, by providing an intermediate layer 12 having an insulating part formed of an insulating material and a magnetic part formed of a magnetic material, the residual magnetic flux density can be improved compared to when the intermediate layer is formed of an insulating material.

[0060] [Differentiation Example 4] In the embodiments described above, the stacked magnet was assumed to be applied to an IPM motor. However, the motor to which the stacked magnet is applied is not limited to an IPM motor. It may also be applied to an SPM motor or an axial gap motor.

[0061] The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate.

[0062] <Application Example 1> It is a stacked magnet, Multiple magnets stacked on top of each other, An intermediate layer having an insulating portion formed of an insulating material and a magnetic portion formed of a magnetic material, wherein the intermediate layer is disposed between adjacent magnets among the plurality of magnets, Stacked magnets. <Application Example 2> The stacked magnet described in Application Example 1, In the cross-section in the stacking direction of the plurality of magnets, The ratio of the area of ​​the magnetic portion to the area of ​​the intermediate layer is 50% or more and 60% or less, characterized in that Stacked magnets. <Application Example 3> A stacked magnet as described in Application Example 1 or Application Example 2, The magnetic part is characterized in that it is in contact with each of the adjacent magnets. Stacked magnets. <Application Example 4> A stacked magnet as described in any one of Application Examples 1 to 3, The magnetic portion is characterized by being formed from the same type of magnetic material as the material used to form each of the plurality of magnets. Stacked magnets. <Application Example 5> A stacked magnet described in any one of Application Examples 1 to 4, The magnetic portion is characterized in that it is not in contact with any of the adjacent magnets. Stacked magnets. <Application Example 6> It is a motor, A rotor having a stacked magnet as described in any one of Application Examples 1 to 5, A stator having a coil, characterized by comprising Motor. [Explanation of symbols]

[0063] 10, 20…Stacked magnets 11…Magnets 110...Stator 12,22…Middle class 120... Rotor 120b... Coil 121,221…Insulation part 122,222...Magnetic part

Claims

1. It is a stacked magnet, Multiple magnets stacked on top of each other, An intermediate layer having an insulating portion formed of an insulating material and a magnetic portion formed of a magnetic material, wherein the intermediate layer is disposed between adjacent magnets among the plurality of magnets, Stacked magnets.

2. A stacked magnet according to claim 1, In the cross-section in the stacking direction of the plurality of magnets, The ratio of the area of ​​the magnetic portion to the area of ​​the intermediate layer is 50% or more and 60% or less, characterized in that Stacked magnets.

3. A stacked magnet according to claim 1 or claim 2, The magnetic part is characterized in that it is in contact with each of the adjacent magnets. Stacked magnets.

4. A stacked magnet according to claim 3, The magnetic portion is characterized by being formed from the same type of magnetic material as the material used to form each of the plurality of magnets. Stacked magnets.

5. A stacked magnet according to claim 1 or claim 2, The magnetic portion is characterized in that it is not in contact with any of the adjacent magnets. Stacked magnets.

6. It is a motor, A rotor having a stacked magnet according to claim 1 or claim 2, A stator having a coil, characterized by comprising Motor.

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