Rotor and motor

Abstract

This invention provides a technology to improve heat dissipation in motor rotors. [Solution] The rotor for the motor comprises a magnet, a rotor core having a support portion for supporting the magnet, and a joint portion that connects the magnet and the support portion, the joint portion mainly containing inorganic material.

Description

Technical Field

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

Background Art

[0002] Conventionally, rotors for motors are known (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0004] However, even with the prior arts such as Patent Documents 1 and 2, there still remains room for improvement regarding the technology for improving heat dissipation performance.

[0005] An object of the present invention is to provide a technology for improving heat dissipation performance in a rotor for a motor.

Means for Solving the Problems

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

[0007] (1) According to one embodiment of the present invention, a rotor for a motor is provided. This rotor includes a magnet, a rotor core portion having a support part for supporting the magnet, and a joint portion that joins the magnet and the support part, the joint portion containing an inorganic substance as a main component.

[0008] In this configuration, the motor rotor is joined to the magnet and the rotor core that supports the magnet by a joint primarily composed of inorganic material. This allows for more efficient transfer of heat from the magnet to the rotor core than, for example, when the magnet and rotor core are joined by resin. Therefore, heat dissipation can be improved, allowing for stable operation even when the magnet becomes hot.

[0009] (2) In addition, in the rotor of the above form, the inorganic material may be a crystalline oxide. With this configuration, the joint that connects the magnet and the rotor core that supports the magnet mainly contains a crystalline oxide. As a result, the heat from the magnet is more easily transferred to the rotor core, thereby improving heat dissipation.

[0010] (3) In addition, in the rotor of the above configuration, the thickness of the joint portion may be 30 μm or more and 100 μm or less. With this configuration, the joint portion that joins the magnet and the rotor core portion that supports the magnet is relatively thin. As a result, heat from the magnet can be easily transferred to the rotor core portion, thereby improving heat dissipation.

[0011] (4) In addition, in the rotor of the above form, the rotor core portion may be formed of composite particles having soft magnetic particles and a plurality of crystalline ceramic particles arranged on the surface of the soft magnetic particles. With this configuration, the rotor core portion is formed of composite particles having soft magnetic particles and a plurality of crystalline ceramic particles arranged on the surface of the soft magnetic particles. This makes it easier to release the heat from the magnet from the rotor core portion, thereby improving heat dissipation.

[0012] (5) According to another embodiment of the present invention, a motor is provided. This motor comprises the rotor described above and a stator for a motor, which is disposed on the rotor and has windings for generating a magnetic field. With this configuration, the rotor has improved heat dissipation and can be used stably even when the magnets become hot. Therefore, the deterioration of the magnets' properties due to heat can be suppressed, and thus the decrease in motor output can be suppressed.

[0013] (6) Furthermore, the motor of the above configuration may be used at a maximum rotational speed of 7500 rpm or higher. With this configuration, the heat generated by the magnet can be efficiently transferred to the rotor core, so that even if the rotor rotational speed is 7500 rpm or higher, the deterioration of the motor's characteristics can be suppressed.

[0014] Furthermore, the present invention can be realized in various forms, for example, in the form of a device using a rotor, a method for manufacturing a rotor, a method for manufacturing a motor, or a computer program that causes a computer to manufacture a rotor or motor. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view of a motor equipped with a rotor according to the first embodiment. [Figure 2] This is a perspective view of the rotor of the first embodiment. [Figure 3] This is a cross-sectional view of the rotor according to the first embodiment. [Figure 4] This is an enlarged view of section A in Figure 3. [Figure 5] This figure illustrates the evaluation results for the rotor of the first embodiment. [Figure 6] This is a cross-sectional view of the rotor of the second embodiment. [Figure 7] This is an enlarged view of section B in Figure 6. [Figure 8] This figure illustrates the evaluation results for the rotor of the second embodiment. [Modes for carrying out the invention]

[0016] <First Embodiment> Figure 1 is a cross-sectional view of a motor including the rotor according to the first embodiment. The rotor 10 of the present embodiment is used in the motor 1 that outputs rotational torque when electric power is supplied. The motor 1 includes a rotor 10, a stator 20, and a motor case 30. The rotor 10 is provided on the central axis C1 of the motor 1 so as to be rotatable around the central axis C1.

[0017] Figure 2 is a perspective view of the rotor of the present embodiment. Figure 3 is a cross-sectional view of the rotor of the present embodiment. The rotor 10 of the present embodiment includes a magnet 11, a rotor core portion 12, and a joint portion 13.

[0018] The magnet 11 is disposed on the rotor core portion 12. The magnet 11 included in the rotor 10 of the present embodiment is a neodymium magnet.

[0019] The rotor core portion 12 has a support portion 120 for supporting the magnet 11. The support portion 120 is a recessed portion formed on the side surface 12a of the rotor core portion 12 having a substantially cylindrical shape. That is, the motor 1 of the present embodiment is a so-called SPM motor in which the magnet 11 is mounted on the surface of the rotor core portion 12. In the present embodiment, four support portions 120 are formed on the side surface 12a of the rotor core portion 12 so as to be arranged along the circumferential direction of the rotor core portion 12. The rotor core portion 12 of the present embodiment is formed of an electromagnetic steel sheet.

[0020] As shown in FIG. 1 and FIG. 2, the rotor core portion 12 has two shaft portions 121 and 122 at both end portions. Each of the shaft portions 121 and 122 has a substantially rod shape whose longitudinal direction is along the central axis C10 of the rotor 10. The end of each of the shaft portions 121 and 122 on the side opposite to the side connected to the rotor core portion 12 is exposed to the outside of the motor case 30 described later.

[0021] The joint 13 connects the magnet 11 and the support part 120. The joint 13 mainly contains inorganic material. Here, "main component" refers to a component that makes up 80% or more of the target member or part. In this embodiment, the joint 13 mainly contains nickel-based alloy, which is a crystalline oxide. Whether or not the inorganic material contained in the joint 13 is a crystalline oxide is determined by combining X-ray diffraction (XRD) and electron probe microanalyzer (EPMA). In analysis using an electron probe microanalyzer, polishing the cross-section of the joint 13 allows for more accurate compositional analysis. Note that the inorganic material contained in the joint 13 that connects the magnet 11 and the support part 120 is not limited to nickel-based alloy, but may also be a Si-Zr-O compound, which is a crystalline oxide, or a titanium alloy, silicon-containing oxide, titanium-nickel alloy, aluminum nitride, carbon fiber, or cement. It is desirable that the inorganic material contained in the joint 13 is nonmagnetic.

[0022] Figure 4 is an enlarged view of part A in Figure 3. The joint 13 is located within the support part 120, between the magnet 11 and the inner wall surface 120a of the support part 120. The thickness D13 of the joint 13 in this embodiment is, for example, 50 μm. It is desirable that the thickness D13 of the joint 13 be between 30 μm and 100 μm. The thickness D13 of the joint 13 is measured by the following measurement method. First, an image is taken of the cross section including the joint 13 as shown in Figure 4 using an SEM (Scanning Electron Microscope). Next, five measurement positions are selected on the joint 13 in the captured SEM image. Next, the thickness is measured at 10 consecutive points at 20 μm intervals at each of the five measurement positions, and the average of the 10 thicknesses is taken as the thickness at each of the five measurement positions. Finally, the average value of the thickness at each of the five measurement positions is calculated and taken as the thickness D13 of the joint 13.

[0023] In the rotor 10 of this embodiment, as shown in Figure 4, an insulating layer 120b made of insulating alumina (Al2O3) is formed on the inner wall surface 120a of the support portion 120. The material forming the insulating layer 120b is not limited to alumina, but may be aluminum nitride (AlN), silicon nitride (Si3N4), yttria (Y2O3), glass, etc. Note that the size relationships of the magnet 11, rotor core portion 12, joint portion 13, and insulating layer 120b shown in Figure 4 differ from the actual relationships for the sake of explanation.

[0024] The stator 20 has a stator core 21 and windings 22 (see Figure 1). The stator 20 is located outside the rotor core 12 and is fixed to the motor case 30 inside the motor case 30, which will be described later. The stator core 21 is formed to have a substantially cylindrical shape and has a plurality of protrusions 211 on its inside. The stator core 21 is formed by laminating a plurality of electromagnetic steel sheets.

[0025] The winding 22 is a conductive wire covered with an insulator and is wound around each of the multiple protrusions 211 of the stator core 21. When electricity supplied from outside the motor 1 flows through the winding 22, it generates a magnetic field.

[0026] The motor case 30 is a hollow component that houses the rotor 10 and the stator 20. The motor case 30 is provided with two bearings 31 and 32. Each of the bearings 31 and 32 is provided on one of two opposing bracket portions 301 and 302 in the motor case 30. One of the two shaft portions 121 and 122 is inserted through bearing 31, and the other shaft portion 122 is inserted through bearing 32. As a result, the rotor 10 is rotatably supported by the motor case 30.

[0027] In the motor 1 of this embodiment, the magnet 11 and the rotor core 12 that supports the magnet 11 are joined by a joint 13 that mainly contains a nickel-based alloy having relatively high thermal conductivity. This allows heat from the magnet 11 to be transferred to the rotor core 12 more efficiently than, for example, when the magnet and the rotor core are joined by resin. Therefore, the deterioration of the properties of the magnet 11 due to heat can be suppressed, and thus the decrease in output of the motor 1 can be suppressed. For example, even when the motor 1 is miniaturized and the rotor 10 is rotated at a rotational speed of, for example, 7500 rpm or more, the temperature rise of the rotor 10 can be suppressed, and thus the decrease in output of the motor 1 can be suppressed.

[0028] Next, the manufacturing method of the motor 1 of this embodiment will be described. First, the manufacturing method of the rotor 10 of this embodiment will be described. In the manufacturing method of the rotor 10 of this embodiment, first, a magnet 11 and a rotor core portion 12 formed from electromagnetic steel sheet are prepared. Next, an insulating layer 120b is formed to insulate the inner wall surfaces 120a of each of the four support portions 120 of the rotor core portion 12. The insulating layer 120b is formed by depositing alumina onto the inner wall surface 120a using methods such as thermal spraying, sputtering, or slurry coating, and then performing heat treatment at a temperature of, for example, 300°C.

[0029] In the manufacturing method of the rotor 10 of this embodiment, in addition to preparing the magnet 11 and the rotor core 12, an adhesive that will form the joint 13 is prepared. Specifically, a mixed slurry for the adhesive is prepared by mixing nickel alloy powder and an inorganic adhesive so that the nickel alloy content is 50 vol% or more.

[0030] In the manufacturing method of the rotor 10 of this embodiment, the prepared mixed slurry is then applied to the magnet 11, and the magnet 11 is press-fitted into the support portion 120 such that the applied mixed slurry is in contact with the insulating layer 120b on the inner wall surface 120a of the support portion 120 of the rotor core portion 12. After press-fitting the magnet 11 into the support portion 120 of the rotor core portion 12, the inorganic adhesive is dried and cured by, for example, holding it in an environment at 25°C for 12 hours, then holding it in an environment at 100°C for 3 hours, and then holding it in an environment at 150°C for 5 hours. This completes the manufacturing of the rotor 10. In the manufacturing method of the motor 1 of this embodiment, the stator 20 and motor case 30 are prepared, and the shaft portions 121 and 122 of the prepared rotor 10 are inserted into the bearings 31 and 32 of the motor case 30, respectively, and the rotor 10 and stator 20 are assembled into the motor case 30. This completes the manufacturing of the motor 1. The manufacturing method for the rotor 10 and motor 1 shown herein is merely an example and is not limited to this method.

[0031] Next, the evaluation test of the rotor in this embodiment will be described. In this evaluation test, 14 types of rotors (hereinafter referred to as "samples") were manufactured, each differing in either the type of magnet, the characteristics of the joint, or the characteristics of the rotor core, and the "thermal characteristics" and "joint strength" of each of the 14 types of samples were evaluated.

[0032] Figure 5 illustrates the evaluation results of the rotor of this embodiment. The 14 types of samples used in this evaluation test were prepared by a method similar to the manufacturing method of the rotor 10 of this embodiment. The joints that connect the magnet and the rotor core of each of Samples 1 to 11 contain inorganic material as the main component. On the other hand, the joints of each of Samples 12 to 14 contain resin as the main component.

[0033] The "thermal properties" shown in Figure 5 indicate the ease of heat transfer between the magnet and the rotor core. In this evaluation test, the temperature change of each sample was measured using the laser flash method to assess the ease of heat transfer between the magnet and the rotor core. Specifically, a measurement sample was prepared, consisting of a magnet, a joint, and a rotor core, with sides of 30 mm. Pulsed light energy was irradiated from the rotor core side, and a temperature response curve was obtained on the magnet side. In this evaluation test, the rate of change of the heat transfer behavior relative to sample 12 was classified as follows using the temperature response curves obtained for each sample. In the following classification, the rate of change relative to sample 12 increases in the order of "C", "B", "A", and "S". A larger rate of change relative to sample 12 indicates that the temperature changes more easily, and that the heat transfer between the magnet and the rotor core is superior. "C": The rate of change relative to sample 12 is 105% or less. "B": The rate of change relative to sample 12 is greater than 105% but less than or equal to 120%. "A": The rate of change relative to sample 12 is greater than 120% but less than or equal to 130%. "S": The rate of change relative to sample 12 is greater than 130%.

[0034] The "joint strength" shown in Figure 5 indicates the strength of the bond between the magnet and the rotor core at the joint. In this evaluation test, the strength of the bond between the magnet and the rotor core at the joint was compared using tensile strength. Specifically, the joint area between the magnet and the rotor core at the joint was 5 cm². 2 The tensile strength of the measurement samples was measured. In this evaluation test, the ratio of the magnitude of the tensile strength of each sample was classified as follows, using the analysis results of the tensile strength of each sample as the reference. "C": The size ratio to sample 12 is 105% or less. "B": The size ratio relative to sample 12 is greater than 105% and less than or equal to 115%. "A": The size ratio to sample 12 is greater than 115%.

[0035] Of the samples 1 to 14 used in this evaluation test, samples 1 to 11, which joined the magnet and rotor core using a joint containing inorganic material as the main component, were confirmed to have an evaluation of "B" or higher in both "thermal properties" and "joint strength" compared to the comparison sample 12, sample 13 which had a joint containing acrylic resin as the main component, and sample 14 which had a joint containing epoxy resin as the main component. In other words, it was confirmed that samples with inorganic material as the main component in the joint allowed heat to be transferred more easily from the magnet to the rotor core and resulted in greater joint strength between the magnet and the rotor core than samples with resin as the main component in the joint.

[0036] Comparing the thermal properties of samples 1 through 11, it was confirmed that samples 6 through 11 had superior thermal properties compared to samples 1 through 5. Furthermore, samples 8 through 11, each with a joint thickness between 30 μm and 100 μm, were found to have superior thermal properties compared to samples 6 and 7. Of samples 8 through 11, samples 9 and 11 feature joints primarily composed of cement, a crystalline oxide. Sample 10, which features a joint primarily composed of a Si-Zr-O compound, a crystalline oxide, was found to have particularly excellent thermal properties and superior joint strength compared to samples 1 through 10 and sample 11.

[0037] As described above, in the rotor 10 of this embodiment, the magnet 11 and the rotor core 12 that supports the magnet 11 are joined by a joint 13 that mainly contains inorganic material. This allows the heat from the magnet 11 to be transferred to the rotor core 12 more efficiently than, for example, when the magnet and the rotor core are joined by resin. Therefore, heat dissipation can be improved, and the magnet 11 can be used stably even when it becomes hot.

[0038] Furthermore, according to the rotor 10 of this embodiment, the joint 13 that connects the magnet 11 and the rotor core 12 that supports the magnet 11 mainly contains a nickel-based alloy, which is a crystalline oxide. As a result, heat from the magnet 11 is more easily transferred to the rotor core 12, thereby improving heat dissipation.

[0039] Furthermore, in the rotor 10 of this embodiment, the joint portion 13 that connects the magnet 11 and the rotor core portion 12 that supports the magnet 11 has a thickness D13 of 50 μm, which is relatively thin. As a result, heat from the magnet 11 is more easily transferred to the rotor core portion 12, thereby improving heat dissipation.

[0040] Furthermore, according to the motor 1 of this embodiment, the rotor 10 has improved heat dissipation, so it can be used stably even when the magnet 11 becomes hot. Therefore, the deterioration of the characteristics of the magnet 11 due to heat can be suppressed, and thus the decrease in output of the motor 1 can be suppressed.

[0041] Furthermore, according to the motor 1 of this embodiment, the heat generated by the magnet 11 can be efficiently transferred to the rotor core 12 in the rotor 10, so even if the rotational speed of the rotor 10 is increased to 7500 rpm or more, a decrease in the output of the motor 1 can be suppressed.

[0042] <Second Embodiment> Figure 6 is a cross-sectional view of the rotor of the second embodiment. Compared to the rotor of the first embodiment (Figure 3), the rotor of the second embodiment uses a different material to form the rotor core.

[0043] The rotor 40 of this embodiment comprises a magnet 11, a rotor core portion 42, and a joint portion 43. The rotor core portion 42 has a support portion 420 for supporting the magnet 11. The support portion 420 is a recessed portion formed on the side surface 42a of the rotor core portion 42, which has a substantially cylindrical shape.

[0044] The rotor core 42 is formed of composite particles having soft magnetic particles and a plurality of crystalline ceramic particles arranged on the surface of the soft magnetic particles. The composite particles forming the rotor core 42 in this embodiment have soft magnetic particles formed of Si3N4 / TiN / Fe and crystalline ceramic particles formed of Si3N4.

[0045] The joint 43 connects the magnet 11 and the support portion 420. The joint 43 mainly contains inorganic material. In this embodiment, the joint 43 mainly contains Nd2O3 / NdO. In this embodiment, the joint 43 is formed by the leaching of neodymium from the magnet 11, which is a neodymium magnet, during the manufacturing process of the rotor 40. Note that the inorganic material contained in the joint 43 that connects the magnet 11 and the support portion 420 is not limited to Nd2O3 / NdO.

[0046] Figure 7 is an enlarged view of section B in Figure 6. The joint 13 is positioned within the support section 420, between the magnet 11 and the inner wall surface 420a of the support section 420. The thickness D13 of the joint 13 in this embodiment is, for example, 53 μm. In the rotor 40 of this embodiment, as shown in Figure 7, the joint 43 joins the magnet 11 and the support section 420 while in direct contact with the inner wall surface 420a of the support section 420. Note that the size relationships between the magnet 11, the rotor core section 42, and the joint 43 shown in Figure 7 differ from the actual relationships for the sake of explanation.

[0047] Next, the manufacturing method of the motor of this embodiment will be described. The manufacturing method of the motor of this embodiment differs from the manufacturing method of the motor 1 of the first embodiment in that it differs in the manufacturing method of the rotor 40. In the manufacturing method of the rotor 40 of this embodiment, composite particles are prepared in which a plurality of crystalline ceramic particles made of Si3N4 are arranged on the surface of soft magnetic particles made of Si3N4 / TiN / Fe. Using the prepared composite particles, a molded body having the shape of a rotor core portion 42 is made, and the rotor core portion 42 is made by firing the molded body. Next, a magnet 11 is placed in the support portion 420 of the made rotor core portion 42, and the magnet 11 and the support portion 420 are joined by pressing them together, for example, under a vacuum atmosphere at a temperature of 800°C with a pressure of 20 MPa. In this way, the manufacturing method of the rotor 40 of this embodiment does not require the insulation treatment on the inner wall surface of the support portion of the rotor core portion that is performed in the manufacturing method of the rotor 10 of the first embodiment. Note that the manufacturing method of the rotor 40 shown here is just one example and is not limited to this manufacturing method.

[0048] Next, the evaluation test of the rotor in this embodiment will be described. In this evaluation test, six types of rotors (hereinafter referred to as "samples") were prepared, each differing in either the type of magnet, the characteristics of the joint, or the characteristics of the rotor core, and the "thermal characteristics" and "joint strength" of each of the six samples were evaluated.

[0049] Figure 8 illustrates the evaluation results for the rotor of this embodiment. Of the six types of samples used in this evaluation test, samples 15 to 17 were manufactured by a method similar to the manufacturing method of the rotor 40 of this embodiment. The joints that connect the magnet and the rotor core of each of samples 15 to 17 contain inorganic material (Nd2O3 / NdO) as the main component. Sample 15 is made of composite particles in which multiple crystalline ceramic particles made of Si3N4 are arranged on the surface of soft magnetic particles made of Si3N4 / TiN / Fe, where the rotor core is made. Samples 16 and 17 are made of composite particles in which multiple crystalline ceramic particles made of Al2O3 / ZrO2 are arranged on the surface of soft magnetic particles made of Al2O3 / ZrO2 / Fe. Each of samples 12 to 14 shown in Figure 8 is the same sample as samples 12 to 14 used in the evaluation test of the first embodiment, and the joints contain resin as the main component. The "thermal properties" and "bonding strength" shown in Figure 8 are evaluated using the same criteria as those described in the evaluation test of the first embodiment.

[0050] As shown in Figure 8, each of samples 15 to 17 was confirmed to have superior performance compared to samples 12 to 14 in terms of both "thermal properties" and "bonding strength." Specifically, in terms of "thermal properties," which indicates how easily heat is transferred, each of samples 15 to 17 was rated "S," confirming that they conduct heat even more easily than samples 1 to 8 of the first embodiment, which were rated "A" or "B." Furthermore, in terms of "bonding strength," which indicates the strength of the bond between the magnet and the rotor core at the joint, each of samples 15 to 17 was rated "A," confirming that they have even greater bonding strength than samples 1 to 9 and sample 11 of the first embodiment, which were rated "B."

[0051] As described above, in the rotor 40 of this embodiment, the magnet 11 and the rotor core 42 that supports the magnet 11 are joined by a joint 43 that mainly contains inorganic material. This allows the heat from the magnet 11 to be efficiently transferred to the rotor core 12, thereby improving heat dissipation.

[0052] Furthermore, according to the rotor 40 of this embodiment, the rotor core 42 is formed of composite particles having soft magnetic particles and a plurality of crystalline ceramic particles arranged on the surface of the soft magnetic particles. This makes it easier to release heat from the magnet 11 from the rotor core 42, thereby further improving heat dissipation.

[0053] <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.

[0054] [Example 1] In the above-described embodiment, the inorganic material contained as the main component of the joint was assumed to be a crystalline oxide. However, the inorganic material does not have to be a crystalline oxide.

[0055] [Differentiation 2] In the first embodiment, the thickness of the joint was set to 50 μm. The thickness of the joint may be greater than 50 μm, but since heat conduction becomes easier as the thickness decreases, it is desirable that it be 100 μm or less. Furthermore, the thickness of the joint may be less than 30 μm, but by setting the thickness to 30 μm or more, a certain level of joint strength can be achieved.

[0056] [Difference 3] In the above-described embodiment, the motor was assumed to be used at a maximum rotational speed of 7500 rpm or higher. The maximum rotational speed of the motor is not limited to this, but because the rotor has excellent heat dissipation, the temperature rise of the rotor can be suppressed even when the rotor is rotated at a rotational speed of 7500 rpm or higher. This makes it possible to suppress a decrease in the motor's output.

[0057] [Differentiation Example 4] In the above-described embodiment, the motor was assumed to be an SPM motor. The motor may also be an IPM motor, in which a support portion for supporting magnets is arranged inside the rotor core. Furthermore, the motor configuration is not limited to the configuration of the above-described embodiment.

[0058] 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.

[0059] <Application Example 1> A rotor for a motor, Magnets and A rotor core section having a support portion for supporting the aforementioned magnet, A joint that connects the magnet and the support, comprising a joint that mainly contains inorganic material, is characterized by having Rotor. <Application Example 2> The rotor described in Application Example 1, The inorganic substance is characterized by being a crystalline oxide. Rotor. <Application Example 3> A rotor as described in Application Example 1 or Application Example 2, The thickness of the joint is characterized by being 30 μm or more and 100 μm or less. Rotor. <Application Example 4> A rotor described in any one of Application Examples 1 to 3, The rotor core is characterized by being formed of composite particles having soft magnetic particles and a plurality of crystalline ceramic particles arranged on the surface of the soft magnetic particles. Rotor. <Application Example 5> It is a motor, A rotor described in any one of Application Examples 1 to 4, The motor is characterized by comprising a stator arranged on the rotor and having windings for generating a magnetic field, Motor. <Application Example 6> The motor described in Application Example 5, It is characterized by being used at a maximum rotational speed of 7500 rpm or higher. Motor. [Explanation of symbols]

[0060] 1…motor 10,40… Rotor 11…Magnets 12,42...Rotor core section 120,420…Support part 13,43…Joint part 20…Status 22...winding

Claims

1. A rotor for a motor, Magnets and A rotor core section having a support portion for supporting the aforementioned magnet, A joint that connects the magnet and the support, comprising a joint that mainly contains inorganic material, is characterized by having Rotor.

2. A rotor according to claim 1, The inorganic substance is characterized by being a crystalline oxide. Rotor.

3. A rotor according to claim 1 or claim 2, The thickness of the joint is characterized by being 30 μm or more and 100 μm or less. Rotor.

4. A rotor according to claim 1 or claim 2, The rotor core is characterized by being formed of composite particles having soft magnetic particles and a plurality of crystalline ceramic particles arranged on the surface of the soft magnetic particles. Rotor.

5. It is a motor, A rotor according to claim 1 or claim 2, The motor is characterized by comprising a stator arranged on the rotor and having windings for generating a magnetic field, Motor.

6. The motor according to claim 5, It is characterized by being used at a maximum rotational speed of 7500 rpm or higher. Motor.

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