Multilayer magnets and motors

Abstract

This invention provides a technology for reducing eddy current losses in multilayer magnets while suppressing the decrease in residual magnetic flux density. [Solution] The stacked magnet consists of multiple stacked magnets and an insulating layer placed between adjacent magnets among the multiple magnets, with a DC resistance value of 1.1 × 10 -3 Ω or more 2.3×10 6 It comprises an insulating layer with a resistance of Ω or less.

Description

[Technical Field]

[0001] This invention relates to a multilayer magnet and a motor. [Background technology]

[0002] Stacked magnets, in which multiple magnets are stacked, have been known for some time (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2009 / 116540 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, even with prior art such as Patent Document 1, there was still room for improvement in techniques for reducing eddy current losses while suppressing the decrease in residual magnetic flux density in stacked magnets.

[0005] The present invention aims to provide a technology for reducing eddy current losses in a stacked magnet while suppressing a decrease in residual magnetic flux density. [Means for solving the problem]

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

[0007] (1) According to one embodiment of the present invention, a laminated magnet is provided. This laminated magnet comprises a plurality of stacked magnets and an insulating layer disposed between adjacent magnets among the plurality of magnets, wherein the DC resistance value is 1.1 × 10 -3 Ω or more 2.3×10 6 It comprises an insulating layer with a resistance of Ω or less.

[0008] According to this configuration, in a stacked magnet, the insulating layer placed between adjacent magnets among the stacked magnets has a DC resistance of 1.1 × 10⁻⁶. -3 Ω or more 2.3×10 6 The value is less than Ω. This allows for a reduction in eddy current loss even when the thickness of the insulating layer is reduced to decrease the proportion of the volume occupied by the insulating layer in the multilayer magnet. Therefore, it is possible to reduce eddy current loss while suppressing the decrease in residual magnetic flux density.

[0009] (2) In the laminated magnet of the above form, the insulating layer may be made of ceramic. With this configuration, the insulating layer is made of ceramic, which is a material with a relatively high DC resistance. As a result, eddy current loss can be reduced even if the thickness of the insulating layer is reduced, and thus eddy current loss can be reduced while suppressing a decrease in residual magnetic flux density.

[0010] (3) In the laminated magnet of the above form, the insulating layer may be made of resin. With this configuration, the insulating layer is made of resin, which is a material with a relatively high DC resistance. As a result, eddy current loss can be reduced even if the thickness of the insulating layer is reduced, and thus eddy current loss can be reduced while suppressing a decrease in residual magnetic flux density.

[0011] (4) According to another embodiment of the present invention, a motor is provided. This motor comprises a rotor having the stacked magnets of the above embodiment and a stator having windings. According to this configuration, the motor has a DC resistance of 1.1 × 10 -3 Ω or more 2.3×10 6 The device is equipped with a laminated magnet having an insulating layer with a resistance of Ω or less. This reduces eddy current losses, thereby suppressing the motor's temperature rise. Consequently, the motor's output can be increased.

[0012] Note that the present invention can be realized in various aspects. For example, it can be realized in the form of a method for manufacturing a laminated magnet, a method for manufacturing an insulating layer provided in the laminated magnet, an apparatus including the laminated magnet, a method for manufacturing an apparatus including the laminated magnet, a control method for an apparatus including the laminated magnet, and the like.

Brief Description of the Drawings

[0013] [Figure 1] It is a perspective view of the laminated magnet of the first embodiment. [Figure 2] It is a cross-sectional view of the laminated magnet of the first embodiment. [Figure 3] It is a cross-sectional view of a motor including the laminated magnet of the first embodiment. [Figure 4] It is a cross-sectional view of a rotor including the laminated magnet of the first embodiment. [[ID=l8]] [Figure 5] It is a diagram for explaining the result of the evaluation test of the laminated magnet of the first embodiment. [Figure 6] It is a cross-sectional view of the laminated magnet of the second embodiment. [Figure 7] It is a diagram for explaining the result of the evaluation test of the laminated magnet of the second embodiment. [Figure 8] It is a perspective view of a modified example of the laminated magnet of the first embodiment.

Modes for Carrying Out the Invention

[0014] <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 a motor 100 including the laminated magnet 10 of the present embodiment. FIG. 4 is a cross-sectional view of a 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 laminated thereon and an insulating layer 12 disposed between adjacent magnets 11 among the plurality of magnets 11. The technical field in which the laminated magnet 10 is used is not limited to this.

[0015] The motor 100 of this embodiment comprises a rotor 110, a stator 120, and a motor case 130. The rotor 110 comprises a rotor member 111 having a substantially cylindrical shape and a stacked magnet 10. In the motor 100 of this embodiment, the stacking direction of the multiple magnets 11 and the insulating layer 12 in the stacked magnet 10 is parallel to the rotation axis C1 of the rotor 110 in the motor 100 (see Figure 3). The stacked magnet 10 is inserted into an insertion hole 112 formed in the rotor 110.

[0016] 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 to include one or more of Nd, Pr, Dy, and Tb as rare earth elements, and it is more desirable to include Nd as the main component. Note that "Nd as the main component" means that Nd has the highest content (mass%) among the rare earth elements. In addition to rare earth elements, magnet 11 may also contain transition metal elements and boron. In the stacked magnet 10 of this embodiment, a plurality of magnets 11 are stacked with an insulating layer 12 in between. The magnetization directions of each of the plurality of 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.

[0017] The insulating layer 12 has a DC resistance of 1.1 × 10⁻⁶ -3 Ω or more 2.3×10 6It is formed of a ceramic with a resistance of Ω or less. The insulating layer 12 preferably 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. The insulating layer 12 preferably contains at least a Group 2A fluoride of the periodic table. More preferably, the insulating layer 12 contains at least one selected from the group consisting of CaF2, BaF2, SrF2, and MgF2 as the Group 2A fluoride of the periodic table. The insulating layer 12 of the present embodiment contains CaF2. The thickness of the insulating layer 12 of the present embodiment is 4 μm. The thickness of the insulating layer 12 is preferably 1 μm or more and 18 μm or less.

[0018] The stator 120 has a stator core portion 121 and a winding 122. The stator 120 is disposed outside the rotor 110 and fixed to the motor case 130 inside the motor case 130 described later. The stator core portion 121 is formed to have a substantially cylindrical shape and has a plurality of protrusions 123 inside. The winding 122 is a conductor wire coated with an insulator and is wound around each of the plurality of protrusions 123 of the stator core portion 121. When electricity supplied from outside the motor 100 flows through the winding 122, a magnetic field is generated.

[0019] The motor case 130 is a hollow member that houses the rotor 110 and the stator 120 inside. Two bearings 131 and 132 are provided in the motor case 130. The two bearings 131 and 132 rotatably support the rotor 110.

[0020] Next, a method for manufacturing the laminated magnet 10 of the present embodiment will be described. In the method for manufacturing the laminated magnet 10, first, a powder of a strip cast alloy (SC alloy) is prepared (preparation step). In the present embodiment, the SC alloy has a composition of Nd2Fe 14This is represented by B. SC alloy is prepared by mixing the main raw materials of Nd / Pr alloy, alloys containing Co, Al, Cu, Ga, and Zr, and elemental metals, under an argon atmosphere. Next, using a hydrogen furnace, the SC alloy is exposed to hydrogen (hydrogen atmosphere, temperature: 200°C, time: 2 hours) to embrittle the grain boundaries (neodymium-rich phase) of the SC alloy (hydrogen decomposition process) and produce SC alloy powder.

[0021] 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.

[0022] 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%.

[0023] 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, 2 to 4 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 5 MPa to 20 MPa and a filling density of 3.0 g / cm³. 3 ~4.0g / cm 3 The relative density is 40% to 52%.

[0024] 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.

[0025] Following the first firing process, the partition plate is removed from the workpiece, and the raw materials for the insulating layer 12 are applied to the surface of the magnet 11 before lamination (insulating layer application process). The raw materials for the insulating layer 12 are a mixture of CaF2 powder, TbF3 compound powder, and a solvent. The proportion of TbF3 compound powder in the raw materials for the insulating layer 12 is, for example, 10% to 20% by mass, and the application thickness is, for example, 2 μm to 18 μm. The application of the raw materials for the insulating layer 12 is carried out in the atmosphere, for example, by spraying. However, the method of applying the raw materials for the insulating layer 12 to the surface of the magnet 11 is not limited to this.

[0026] Following the insulating layer coating process, multiple magnets 11 coated with the insulating layer 12 material 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 a uniaxial hot press is performed (hot pressing process). In the hot pressing process, for example, the pressure is 10 -3 Pa~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 time is, for example, 10 minutes to 20 hours. This process produces the laminated magnet 10.

[0027] Next, the evaluation test of the laminated magnet in this embodiment will be described. In this evaluation test, eight types of laminated magnets with different insulating layer thicknesses (hereinafter referred to as "samples") were prepared, and for each of the eight types of samples, the "DC resistance value," "residual magnetic flux density," "eddy current loss ratio," and "motor magnet temperature" were measured or calculated.

[0028] Figure 5 illustrates the evaluation results of the laminated magnet of this embodiment. The eight 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. The insulating layer of each of Samples 1 to 7 contains CaF2. Sample 8 is a comparative example in this evaluation test and does not have an insulating layer, having a structure in which two magnets are simply stacked. In Figure 5, for each of Samples 1 to 7 that have an insulating layer, the groups classified according to the following criteria based on the thickness of the insulating layer are shown as "Classification". A: Greater than 0 μm and less than or equal to 6 μm. B: Larger than 6 μm and 18 μm or less C: Larger than 18 μm and less than or equal to 30 μm D: Greater than 30 μm In this evaluation test, the thickness of the insulating layer in Sample 1 and Sample 2 belongs to Group B, while the thickness of the insulating layer in Samples 3 through 7 belongs to Group A. Figure 5 shows the percentage of the insulating layer relative to the entire stacked magnet for each of Samples 1 through 8, expressed as the "volume percentage (%)" of the "insulating layer". The size of the magnets in the samples used in this evaluation test is 6 mm in the magnetization direction × 2 mm in the stacking direction × 20 mm, and the size of the stacked magnet is 6 mm in the magnetization direction × 40 mm in the stacking direction × 20 mm.

[0029] The "DC resistance values" shown in Figure 5 are those measured using the four-terminal method with a resistance meter. Figure 5 shows the DC resistance values ​​of the "laminated magnets" for each of Samples 1 to 8, and the DC resistance values ​​of the "insulating layer only" for each of Samples 1 to 7, excluding Sample 8 which does not have an insulating layer. The DC resistance values ​​of the "laminated magnets" represent the DC resistance values ​​with one insulating layer sandwiched between two magnets. The DC resistance values ​​of the "insulating layer only" were calculated by subtracting the DC resistance value of the "laminated magnet" of Sample 8, which consists of only two magnets, from the DC resistance value of the "laminated magnet" for each sample.

[0030] The "residual magnetic flux density" shown in Figure 5 was calculated using the "volume percentage (%)" of the "insulating layer" for each of Samples 1 to 7, with the "residual magnetic flux density" of Sample 8 as the baseline. Specifically, it was calculated by subtracting the percentage of the "volume percentage (%)" of the "insulating layer" for each of Samples 1 to 7 from 1 and multiplying this value by the "residual magnetic flux density (T)" of Sample 8.

[0031] The "Eddy Current Loss Ratio (%)" shown in Figure 5 was calculated by measuring the eddy current loss for each of Samples 1 to 8 and determining the ratio of the eddy current loss values ​​when the eddy current loss value for Sample 8 was set to 100. The eddy current loss for each of Samples 1 to 8 was calculated by placing the sample inside the air-core coil and measuring the AC resistance value of the air-core coil using an LCR meter when an AC magnetic field with a frequency of 500 Hz was applied.

[0032] The "motor magnet temperature (°C)" shown in Figure 5 was calculated using the "eddy current loss ratio (%)". Specifically, the "motor magnet temperature (°C)" for sample 8, which had an "eddy current loss ratio (%)" of 100%, was set to 80°C, and the "motor magnet temperature (°C)" for sample 1, which had an "eddy current loss ratio (%)" of 73%, was set to 55°C. The "motor magnet temperature (°C)" for each of samples 2 to 7 was then calculated using the respective "eddy current loss ratios (%)" of samples 2 to 7.

[0033] The "Overall Evaluation" shown in Figure 5 presents the results for each of Samples 1 to 7, using scores assigned to both the grouping results of the "insulating layer thickness" and the calculated results of the "motor magnet temperature." Specifically, in the grouping of the "insulating layer," the scores were set as follows, according to the classified "thickness classification" group. Group A: 3 points Group B: 2 points Group C: 1 point Group D: 0 points In calculating the "motor magnet temperature (°C)," points are assigned according to the magnitude of the calculated value, as follows: 55℃ or higher but less than 60℃: 5 points 60℃ or higher but less than 65℃: 3 points 65℃ or higher but less than 70℃: 1 point 70℃ or higher: 0 points The "Overall Evaluation" was calculated by summing the scores based on the grouping of "insulating layer thickness" and the scores based on the calculated "motor magnet temperature" for each of the eight samples (1 to 8), and then classifying them as follows. 8 points or more: S 6 or 7 points: A 4 or 5 points: B 3 points or less: C

[0034] As shown in Figure 5, the DC resistance value of the insulating layer in each of Samples 1 to 6 is 1.1 × 10⁻⁶. -3 Ω or more 2.3×10 6The value was less than Ω, and it was confirmed that the eddy current loss ratio was smaller than that of sample 8. In each of samples 1 to 6, the insulating layer has such a DC resistance value, so the proportion of the insulating layer to the entire laminated magnet ("volume ratio") can be kept to 1% or less. This suppresses the decrease in residual magnetic flux density. In other words, in the laminated magnet, the DC resistance value is 1.1 × 10⁻⁶. -3 Ω or more 2.3×10 6 By providing an insulating layer containing CaF2 with a resistance of Ω or less, it is possible to reduce eddy current losses while suppressing the decrease in residual magnetic flux density.

[0035] As shown in Figure 5, among samples 1 to 7 which have an insulating layer, sample 7, with an insulating layer volume percentage of 0.1%, has a relatively large eddy current loss ratio, resulting in a relatively high motor magnet temperature. On the other hand, samples 1 to 6 have an insulating layer volume percentage of approximately 0.2% to 0.5%, resulting in a relatively small eddy current loss ratio and a less pronounced motor magnet temperature. Therefore, when using the laminated magnets of samples 1 to 6 in a motor, the motor temperature rise can be suppressed. This allows for an increase in motor output.

[0036] According to the stacked magnet 10 of this embodiment described above, in the stacked magnet 10, the insulating layer 12 placed between adjacent magnets 11 among the multiple stacked magnets 11 has a DC resistance value of 1.1 × 10 -3 Ω or more 2.3×10 6 The resistance is less than Ω. This allows for a reduction in eddy current loss even when the thickness of the insulating layer 12 is reduced to decrease the proportion of the volume occupied by the insulating layer 12 in the laminated magnet 10. Therefore, it is possible to reduce eddy current loss while suppressing a decrease in residual magnetic flux density.

[0037] Furthermore, the laminated magnet 10 of this embodiment is formed of CaF2, a material with a relatively high DC resistance. As a result, eddy current loss can be reduced even if the thickness of the insulating layer 12 is reduced, thus reducing eddy current loss while suppressing a decrease in residual magnetic flux density.

[0038] Furthermore, according to the motor 100 of this embodiment, the motor 100 has a DC resistance value of 1.1 × 10 -3 Ω or more 2.3×10 6 The device is equipped with a laminated magnet 10 having an insulating layer 12 with a resistance of Ω or less. This reduces eddy current losses, thereby suppressing the temperature rise of the motor. Consequently, the output of the motor 100 can be increased.

[0039] <Second Embodiment> Figure 6 is a cross-sectional view of the laminated magnet 20 of the second embodiment. The laminated magnet 20 of the second embodiment differs from the laminated magnet 10 of the first embodiment (Figure 1) in that the insulating layer is formed of resin.

[0040] The stacked magnet 20 of the second embodiment, as shown in Figure 6, comprises a plurality of stacked magnets 11 and an insulating layer 22 disposed between adjacent magnets 11. The insulating layer 22 has a DC resistance of 1.1 × 10⁻¹⁰. -4 Ω or more 2.3×10 6 It is formed from a resin with a impedance of Ω or less. The insulating layer 22 of this embodiment is formed from epoxy resin.

[0041] Next, the manufacturing method of the stacked magnet 20 of this embodiment will be described. In the manufacturing method of the stacked magnet 20, first, a plurality of magnets 11 are manufactured. Specifically, they are manufactured by a method similar to the manufacturing method of the magnets 11 in the manufacturing method of the stacked magnet 10 of the first embodiment.

[0042] In the manufacturing method of the laminated magnet 20, epoxy resin is applied to the surface of the magnet 11 before lamination. After applying epoxy resin to the surface of the magnet 11, two magnets 11 are bonded together by the applied epoxy resin. By performing this process for each of the multiple magnets 11, the laminated magnet 10 is manufactured.

[0043] Next, the evaluation test of the laminated magnet in this embodiment will be described. In this evaluation test, three types of samples with different insulating layer thicknesses were prepared, and for each of the three types of samples, the "DC resistance value," "residual magnetic flux density," "eddy current loss ratio," and "motor magnet temperature" were measured or calculated in the same manner as in the evaluation test of the first embodiment.

[0044] Figure 7 illustrates the evaluation results of the laminated magnet of this embodiment. The three types of samples used in this evaluation test were manufactured by a method similar to the manufacturing method of the laminated magnet 20 of this embodiment. The insulating layers of sample 9 and sample 10 are made of epoxy resin. Sample 8 is the same sample as sample 8 used in the evaluation test of the first embodiment, and does not have an insulating layer, having a structure in which two magnets are simply stacked. In Figure 7, the classification groups of sample 9 and sample 10 according to the thickness of the insulating layer are shown as "Classification". Sample 9 belongs to group D, and sample 10 belongs to group C. In Figure 7, the proportion of the insulating layer to the entire laminated magnet is shown as "Volume Percentage (%)" of "Insulating Layer" for each of sample 9 and sample 10. The size of the magnets and the size of the laminated magnet of the samples used in this evaluation test are the same as in the evaluation test of the first embodiment.

[0045] The "DC resistance (Ω)", "residual magnetic flux density (T)", "eddy current loss ratio (%)", and "motor magnet temperature (°C)" shown in Figure 7 were measured or calculated using the same method as in the evaluation test of the first embodiment. In the "overall evaluation" shown in Figure 7, each of Sample 9 and Sample 10 was evaluated using the same method as the "overall evaluation" determination method in the evaluation test of the first embodiment.

[0046] As shown in Figure 7, the DC resistance of the insulating layer of sample 9 and sample 10 is 1.1 × 10⁻⁶. -3 Ω or more 2.3×10 6 It was confirmed that the eddy current loss ratio was smaller than that of sample 8 because the resistance was less than Ω. Since the insulating layer of sample 9 and sample 10 has such a DC resistance value, the proportion of the insulating layer to the entire laminated magnet ("volume ratio") can be kept to 2.4% or less. This suppresses the decrease in residual magnetic flux density. In other words, in the laminated magnet, the DC resistance value is 1.1 × 10⁻⁶. -3 Ω or more 2.3×10 6 By providing an insulating layer made of epoxy resin with a capacitance of Ω or less, it is possible to reduce eddy current losses while suppressing the decrease in residual magnetic flux density.

[0047] According to the stacked magnet 20 of this embodiment described above, in the stacked magnet 20, the insulating layer 22 placed between adjacent magnets 11 among the multiple stacked magnets 11 has a DC resistance value of 1.1 × 10 -3 Ω or more 2.3×10 6 The resistance is less than Ω. This allows for a reduction in eddy current loss even when the thickness of the insulating layer 22 is reduced to decrease the proportion of the volume occupied by the insulating layer 22 in the laminated magnet 10. Therefore, it is possible to reduce eddy current loss while suppressing a decrease in residual magnetic flux density.

[0048] Furthermore, the laminated magnet 20 of this embodiment is formed of epoxy resin, which is a material with a relatively high DC resistance. As a result, eddy current loss can be reduced even if the thickness of the insulating layer 22 is reduced, thus reducing eddy current loss while suppressing a decrease in residual magnetic flux density.

[0049] <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.

[0050] [Example 1] In the above embodiment, the insulating layer of the laminated magnet is formed of ceramic or resin. The material forming the insulating layer is not limited to these. DC resistance value is 1.1 × 10 -3 Ω or more 2.3×10 6 It is acceptable as long as it is less than or equal to Ω.

[0051] [Differentiation 2] 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.

[0052] Figure 8 is a perspective view of a modified example of the laminated magnet 10 of the first embodiment. The laminated magnet 10 shown in Figure 8 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, the DC resistance value of the insulating layer 12 is 1.1 × 10⁻¹⁰. -3 Ω or more 2.3×10 6 By reducing the value to Ω or less, it is possible to reduce eddy current losses in the stacked magnet 10 while suppressing a decrease in residual magnetic flux density.

[0053] 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.

[0054] <Application Example 1> It is a stacked magnet, Multiple magnets stacked on top of each other, An insulating layer disposed between adjacent magnets among the plurality of magnets, wherein the DC resistance value is 1.1 × 10 -3 Ω or more 2.3×10 6 A feature comprising an insulating layer with an impedance of Ω or less, Stacked magnets. <Application Example 2> The stacked magnet described in Application Example 1, The insulating layer is characterized by being formed of ceramic. Stacked magnets. <Application Example 3> A stacked magnet as described in Application Example 1 or Application Example 2, The insulating layer is characterized by being formed of a resin. Stacked magnets. <Application Example 4> It is a motor, A rotor having a stacked magnet as described in any one of Application Examples 1 to 3, A stator having windings, Motor. [Explanation of Symbols]

[0055] 10, 20…Stacked magnets 11…Magnets 12,22…Insulating layer

Claims

1. It is a stacked magnet, Multiple magnets stacked on top of each other, An insulating layer disposed between adjacent magnets among the plurality of magnets, wherein the DC resistance value is 1.1 × 10 -3 Ω or more 2.3×10 6 A feature comprising an insulating layer with an impedance of Ω or less, Stacked magnets.

2. A stacked magnet according to claim 1, The insulating layer is characterized by being formed of ceramic. Stacked magnets.

3. A stacked magnet according to claim 1, The insulating layer is characterized by being formed of a resin. Stacked magnets.

4. It is a motor, A rotor having a stacked magnet according to any one of claims 1 to 3, A stator having windings, Motor.

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