Rotor and the permanent magnet motor-generator containing it

Abstract

The present invention relates to a rotor comprising: 2n (n≥ 1) magnetic poles; a shaft; a rotating component formed from a non-magnetic material and connected to the shaft;and n magnetic connecting components, each having a curved shape and connected to an outer circumferential side of the rotating component such that they form a protrusion to the shaft, each magnetic connecting component comprising a magnetic south pole, which is an anisotropic magnet acting as an S-pole on the outer circumferential side of the rotating component, a magnetic north pole, which is an anisotropic magnet acting as an N-pole on the outer circumferential side of the rotating component, and a coupling area made of a soft magnetic material, wherein the coupling area is inserted between the magnetic south pole and the magnetic north pole, and wherein, if the coupling area is inserted in a left-right direction between the magnetic south pole and the magnetic north pole, the curved shape is bilaterally symmetric, and the shape of the coupling area is also bilaterally symmetric.

Description

Technical area

[0001] The present invention relates to a rotor and a permanent magnet motor generator having the rotor. State of the art

[0002] In the prior art, a permanent magnet motor generator has been proposed.

[0003] For example, Reference 1 describes a permanent magnet motor generator having the following configurations (1) to (3): (1) The permanent magnet motor generator includes an inner rotor having 2n (n≥1) magnetic poles, and an outer stator having teeth arranged in a radial shape toward the inner rotor and coils wound around the teeth. (2) The inner rotor includes a shaft, a rotor yoke connected to the outer peripheral surface of the shaft, and n magnets connected to a surface of the rotor yoke or embedded in the rotor yoke. (3) The magnet is formed of a special polar anisotropic magnet, and the polar anisotropic magnet is connected to the surface of the rotor yoke or embedded in the rotor yoke such that an N pole and an S pole face an outer peripheral surface side of the inner rotor.

[0004] Publication 1: JP 2018-38162 A Brief description of the invention

[0005] In a permanent magnet motor generator, it is preferable for cost reasons and the like to have a small number of magnets.

[0006] It is an object of the present invention to provide a motor generator which makes it possible to exhibit a high rated power even with a small amount of magnets used, and a rotor which can be used for the motor generator.

[0007] The present invention is as follows in (1) to (6): (1) A rotor, with: 2n (n≥1) magnetic poles; a shaft; a rotating member formed from a non-magnetic material and connected to the shaft; and n magnetic composite bodies, each having a curved shape and are connected to an outer peripheral side of the rotary component in such a way that they represent a protrusion towards the shaft, wherein the magnetic composite bodies include a magnetic south pole, which is an anisotropic magnet acting as an S-pole on the outer peripheral surface of the rotating member, and a magnetic north pole, which is an anisotropic magnet acting as an N-pole on the outer peripheral surface of the rotating member, and a coupling region formed of a soft magnetic material, wherein the coupling region is inserted between the magnetic south pole and the magnetic north pole, and wherein, when the coupling region is inserted in a left-right direction between the magnetic south pole and the magnetic north pole, the bent shape is bilaterally symmetric, and a shape of the coupling region is also bilaterally symmetric. (2) The rotor according to (1), with a volume fraction of the coupling region in the magnet composite body of 40% to 70%. (3) The rotor according to (1) or (2), wherein each of the magnetic south poles and the magnetic north poles is aligned such that an axis of easy magnetization forms an arc shape, the arc is part of a concentric circle, and a center point C1 of an arc of the magnetic south pole and a center point C2 of an arc of the magnetic north pole are arranged at bilaterally symmetrical positions or coincide with each other. (4) The rotor according to any one of (1) to (3), wherein a surface S α that comes into contact with the coupling area in the magnet south pole has the same shape as a surface S1 that comes into contact with the magnet south pole in the coupling area, or the surface S α smaller than the surface S1 and is contained in the surface S1, and where a surface S βthat comes into contact with the coupling area in the magnet south pole has the same shape as a surface S2 that comes into contact with the magnet south pole in the coupling area, or the surface S α smaller than the surface S2 and is contained in the surface S2. (5) A permanent magnet motor generator comprising: the rotor according to (1) or (2) as the inner rotor; and an outer stator with a central through-hole into which the inner rotor is inserted. (6) The permanent magnet motor generator according to (5), wherein the outer stator has: a plurality of teeth serving as an iron core of an armature coil and arranged in a radial shape; and coils wound around the teeth.

[0008] The present invention can provide a motor generator capable of exhibiting a high rated power even with a small amount of magnets, and a rotor usable for the motor generator. Short description of the drawings Fig. 1 is a view (schematic view) of a motor generator according to the present invention, viewed from a direction parallel to a shaft at the center. Fig. 2A to 2G are views (schematic views) of a magnet composite body according to the present invention, viewed from a direction parallel to the shaft. Fig. 3 is a view showing a magnet composite body used in an embodiment. Fig. 4 is an experimental result (graph) showing a relationship between a volume fraction of a coupling region (soft magnetic material) in the magnet composite body according to the present invention and the rated power. Description of the embodiments

[0009] The present invention will now be described. The present invention provides a rotor comprising: 2n (n≥1) magnetic poles; a shaft; a rotating member formed of a soft magnetic material and connected to the shaft;and n magnetic composite bodies, each having a curved shape and connected to an outer peripheral surface of the rotating member in such a way as to form a protrusion toward the shaft, in which the magnetic composite body includes a magnetic south pole, which is an anisotropic magnet functioning as an S pole, on the outer peripheral surface of the rotating member, a magnetic north pole, which is an anisotropic magnet functioning as an N pole, on the outer peripheral surface of the rotating member, and a coupling portion formed of a soft magnetic material, wherein the coupling portion is inserted between the magnetic south pole and the magnetic north pole, and wherein, when the coupling portion is inserted in a left-right direction between the magnetic south pole and the magnetic north pole, the curved shape is bilaterally symmetrical, and a shape of the coupling portion is also bilaterally symmetrical.

[0010] Hereinafter, such a rotor is also referred to as “rotor according to the present invention”.

[0011] Hereinafter, the magnetic composite body included in the rotor according to the present invention is also referred to as “magnetic composite body according to the present invention”.

[0012] The present invention further provides a permanent magnet motor generator including the rotor according to the present invention as an inner rotor, and an outer stator having a central through-hole into which the inner rotor is inserted.

[0013] Hereinafter, such a permanent magnet motor generator is also referred to as “motor generator according to the present invention”.

[0014] The rotor according to the present invention and the motor generator according to the present invention will now be described with reference to the drawings. Fig. 1 is a view (schematic view) of the motor generator according to the present invention, viewed from a direction parallel to the shaft at the center of the rotor according to the present invention. Please note that Fig. 1 shows an example of the rotor according to the present invention and the motor generator according to the present invention including the rotor according to the present invention, and that the rotor according to the present invention and the motor generator according to the present invention are not limited to the Fig. 1 shown embodiment is limited.

[0015] As in Fig. As shown in Figure 1, a motor generator 1 according to the present invention includes an inner rotor 2 and an outer stator 3. Here, the inner rotor 2 corresponds to the rotor according to the present invention. A through hole is formed in the center of the outer stator 3, and the inner rotor 2 is inserted into the through hole.

[0016] The inner rotor 3 includes a shaft 22, a rotating component 24 and a magnet composite body 26.

[0017] The shaft 22 is a rotation shaft (shaft) in the center of the inner rotor 22.

[0018] The rotating component 24 is connected to the shaft 22. The rotating component 24 is formed from a non-magnetic material. Examples of non-magnetic materials forming the rotating component 24 include titanium, aluminum, resin, ceramic, and carbon fiber reinforced plastics (CFRP).

[0019] When the motor generator 1 according to the present invention is viewed from a direction parallel to the shaft 22 in the center, the magnet composite body 26 has a curved shape as shown in Fig. 1. That is, a cross section of the magnet composite body 26 in a direction perpendicular to the shaft 22 has a curved shape. The magnet composite body 26 is arranged on an outer peripheral side of the rotating member 24 in such a way that it presents protrusions toward the shaft 22. In the Fig. In the embodiment shown in Figure 1, the composite magnet body 26 is embedded in the rotating component 24. Alternatively, the composite magnet body 26 may be bonded to an outer peripheral surface of the rotating component 24. That is, the composite magnet body 26 may constitute at least a portion of the outer peripheral surface of the rotating component 24.

[0020] In the case that the number of magnetic composite bodies is 26 n, the inner rotor 2 contains just 2n (n≥1) magnetic poles. Fig. 1 shows an example in which there are eight magnetic composite bodies 26, and the inner rotor 2 includes 16 magnetic poles. The number of magnetic poles present in the inner rotor 2 is not particularly limited. Generally, as the number of magnetic poles increases, the number of switching points of the magnetic flux entangled with a coil increases. Even considering the reduction of magnets in each pole, the torque and generated power are improved as the number of magnetic poles increases, at the same rotational speed. To achieve this effect, the number of magnetic poles is preferably 4 or more, and more preferably 8 or more. On the other hand, if the number of magnetic poles becomes too large, the stator shape and winding become complicated, and there arises the problem of increasing the motor size, which is particularly significant for small motors. Therefore, the number of magnetic poles is preferably 16 or less, and more preferably 12 or less.

[0021] The magnetic composite body 26 (magnetic composite body according to the present invention) will now be described in more detail with reference to Fig. 2A to 2G. Fig. 2A to 2G are views (schematic views) of the magnet composite body 26 arranged on the outer peripheral side of the rotating member 24 when the motor generator according to the present invention is viewed from a direction parallel to the longitudinal direction of the shaft at the center.

[0022] Each of the magnetic composite bodies 26 in the Fig. 2A to 2G has a curved shape and corresponds to the magnetic composite body 26 according to the present invention. Each of the magnetic composite bodies 26 in the embodiments shown in Fig. 2A to 2G includes: a magnetic south pole 262, which is an anisotropic magnet that functions as an S pole on an outer peripheral surface of the rotating member 24; a magnetic north pole 264, which is an anisotropic magnet that functions as an N pole on an outer peripheral surface of the rotating member 24; and a coupling portion 266 formed of a soft magnetic material. The coupling portion 266 is interposed between the magnetic south pole 262 and the magnetic north pole 264.

[0023] The magnet composite body 26 in the Fig. 2A has a shape obtained by cutting a cylinder in a direction parallel to the axis of the cylinder and cutting out a part of the cylinder. Therefore, the curvatures of an outer peripheral surface S out and an inner circumferential surface S inof the coupling region 266 are the same as the curvatures of an outer peripheral surface and an inner peripheral surface of both the magnet south pole 262 and the magnet north pole 264 in Fig. 2A.

[0024] The shape of the magnetic south pole 262 and the magnetic north pole 264 in the magnetic composite body 26 in the Fig. 2B are the same as those of the magnet composite body 26 in the embodiment shown in Fig. 2A, but the shape of the coupling region 266 in the embodiment shown in Fig. 2B differs from that of the coupling region 266 in the embodiment shown in Fig. 2A shown embodiment. In Fig. 2B form both the outer peripheral surface S out as well as the inner circumferential surface S in of the coupling area 266 straight lines.

[0025] The shape of the magnetic south pole 262 and the magnetic north pole 264 in the magnetic composite body 26 in the Fig. 2C are the same as those of the magnet composite body 26 in the embodiment shown in Fig. 2A, but the shape of the coupling region 266 in the embodiment shown in Fig. 2C differs from that of the coupling region 266 in the embodiment shown in Fig. 2A shown embodiment. In Fig. 2C has the inner circumferential surface S in of the coupling region 266 has the same curvature as the inner circumferential surfaces of the magnet south pole 262 and the magnet north pole 264. The outer circumferential surface S out of the coupling region 266 forms a straight line.

[0026] The shape of the magnetic south pole 262 and the magnetic north pole 264 in the magnetic composite body 26 in the Fig. 2D are the same as those of the magnet composite body 26 in the embodiment shown in Fig. 2A, but the shape of the coupling region 266 in the embodiment shown in Fig. 2D differs from that of the coupling region 266 in the embodiment shown in Fig. 2A shown embodiment. In Fig. 2D has the outer peripheral surface S out of the coupling region 266 has the same curvature as the outer circumferential surfaces of the magnet south pole 262 and the magnet north pole 264. The inner circumferential surface S in of the coupling region 266 forms a straight line.

[0027] Similar to the magnetic south pole 262 and the magnetic north pole 264 of the magnetic composite body 26 in the Fig. 2A, the magnet composite body 26 in the embodiment shown in Fig. 2E, the shape is obtained by cutting a cylinder in a direction parallel to the axis of the cylinder and cutting out a part of the cylinder. In Fig. 2E has the outer peripheral surface S outof the coupling region 266 has the same curvature as the outer circumferential surfaces of the magnet south pole 262 and the magnet north pole 264. Here, the inner circumferential surface S in of the coupling area 266 is not present. In Fig. 2E, the coupling region 266 represents a circular sector shape.

[0028] The shape of the magnetic south pole 262 and the magnetic north pole 264 in the magnetic composite body 26 in the Fig. 2F are the same as those of the magnet composite body 26 in the embodiment shown in Fig. 2E, but the shape of the coupling region 266 in the embodiment shown in Fig. 2F differs from that of the coupling region 266 in the embodiment shown in Fig. 2E. Similar to the embodiment shown in Fig. 2E, the inner peripheral surface S in of the coupling area 266 is not present. Similar to the Fig. 2B, the outer peripheral surface S out of the coupling area 266 a straight line. In Fig. 2F, the coupling region 266 represents a triangular shape.

[0029] Similar to the magnetic south pole 262 and the magnetic north pole 264 of the magnetic composite body 26 in the Fig. 2A, the magnet composite body 26 in the embodiment shown in Fig. 2G, the magnet has a shape obtained by cutting a cylinder in a direction parallel to the axis of the cylinder and cutting out a portion of the cylinder. Both a boundary line between the magnet south pole 262 and the coupling region 266 and a boundary line between the magnet north pole 264 and the coupling region 266 are parallel to the symmetry axis L. The symmetry axis L will be described below. The curvatures of the outer peripheral surface S out and the inner peripheral surface S inof the coupling region 266 are the same as the curvatures of the outer peripheral surface and the inner peripheral surface of the magnet south pole 262 and the magnet north pole 264 in Fig. 2G.

[0030] As in the Fig. 2A to 2G, the magnet composite body 26 includes the magnet south pole 262, the magnet north pole 264 and the coupling portion 266, and the coupling portion 266 is inserted between the magnet south pole 262 and the magnet north pole 264. As in the Fig. As shown in FIGS. 2A to 2G, the magnetic composite body 26, when viewed from the direction in which the coupling region 266 is inserted between the magnetic south pole 262 and the magnetic north pole 264 in the left-right direction, is bilaterally symmetric (axisymmetric) to the symmetry axis L. Similarly, the coupling region 266 itself is also bilaterally symmetric. Therefore, the magnetic south pole 262 and the magnetic north pole 264 also have bilaterally symmetric shapes.

[0031] It is preferred that the magnetic south pole 262 and the magnetic north pole 264 are each oriented such that their axes of easy magnetization assume an arc shape. It is preferred that the arcs formed by the axes of easy magnetization in each magnet represent concentric circles.

[0032] In this case, in Fig. 2A to 2G, the arcs formed by the axes of easy magnetization in the south magnet pole 262 are concentric circles, and the center of the concentric circles is designated C1. Similarly, the arcs formed by the axes of easy magnetization in the north magnet pole 264 are concentric circles, and the center of the concentric circles is designated C2. Fig. 2A to 2G, the axes of easy magnetization or an orientation are indicated by dotted lines. In this case, it is preferred that the center point C1 of the arcs in the magnetic south pole 262 and the center point C2 of the arcs in the magnetic north pole 264 are located at bilaterally symmetrical positions with respect to the symmetry axis L, or coincide. In all Fig. In the embodiments shown in Figures 2A to 2G, the center point C1 of the arcs in the magnetic south pole 262 and the center point C2 of the arcs in the magnetic north pole 264 are located at bilaterally symmetrical positions with respect to the symmetry axis L. In this case, the peak magnetic flux density between the N pole and the S pole is increased, a change in the magnetic flux density becomes smooth, and an effect of avoiding torque pulsation occurs.

[0033] It is preferred that the surface S α , which comes into contact with the coupling region 266 in the magnet south pole 262, has the same shape as that surface S1 of the coupling region 266 which comes into contact with the magnet south pole 262, or that the surface S α is smaller than the surface S1 and is contained in the surface S1. Similarly, it is preferred that the surface S β, which comes into contact with the coupling region 266 in the magnetic north pole 264, has the same shape as that surface S2 of the coupling region 266 which comes into contact with the magnetic north pole 264, or that the surface S β is smaller than the surface S2 and is contained in the surface S2. In this case, magnetic leakage flux from the magnet can be minimized, the torque / magnet quantity is further increased, and the effect of contributing to the miniaturization of the motor occurs.

[0034] Materials and manufacturing processes for the magnetic south pole 262 and the magnetic north pole 264 are now described. It is preferable that the magnetic south pole 262 and the magnetic north pole 264 can be aligned in an arc shape and are formed of a material having a high coercive force. Examples of the material include an RTB-based rare earth alloy (R represents a rare earth element such as Nd, Pr, Dy, and Tb; and T represents a transition metal element such as Fe and Co), an R-Co-based alloy (R represents a rare earth element such as Sm), and an R-Fe-based alloy (R represents a rare earth element such as Sm).

[0035] The magnetic south pole 262 and the magnetic north pole 264 can be manufactured, for example, by the following method. First, an arc-shaped or U-shaped green body is prepared. The green body can be manufactured, for example, by a method of compacting and molding powder into an arc shape or a U-shape, by a method of obtaining a green body by press-molding methods such as cold isostatic pressing (CIP), and by a method of obtaining a sintered body by spark plasma sintering (SPS), metal powder spray molding, or the like.

[0036] Next, a magnet with a curved cross-section can be manufactured by simultaneously compressing the arc-shaped or U-shaped green body along a circumferential direction under hot conditions and increasing the thickness in the radial direction. When the arc-shaped green body is subjected to a hot forming process, the thickness in the radial direction can be increased by simultaneously compressing the arc-shaped green body in the circumferential direction while optimizing the shape of a die. As a result, an anisotropic magnet with a curved shape can be manufactured from the arc-shaped green body. When the arc-shaped green body is plastically deformed under hot conditions, a low-melting-point grain boundary phase liquefies around the crystal grains, allowing the crystal grains to rotate and move. When the arc-shaped green body is plastically deformed into an anisotropic magnet, compressive stress is exerted along the circumferential direction of the arc-shaped green body, and tensile stress is simultaneously exerted along the radial and longitudinal directions. Accordingly, the easy magnetization axes of the anisotropic magnet are mainly aligned in the circumferential direction. The deformation can be applied sequentially during the deformation process, and the desired overall degree of deformation can ultimately be achieved.

[0037] Next, excess portions of the curved cross-section magnet are removed, if necessary. If excess portions of the anisotropic magnet are removed by grinding after the curved green body has been plastically formed into the anisotropic magnet, a pre-magnetized magnet can be obtained, which can be used as the magnet south pole 262 and the magnet north pole 264.

[0038] Then, the magnet south pole 262 is magnetized to act as an S pole, and the magnet north pole 264 is magnetized to act as an N pole in the same way, by air-core magnetization.

[0039] The coupling region 266 is formed from a soft magnetic material. Examples of the soft magnetic material forming the coupling region 266 include Fe-Si, iron, permalloy, and permendur.

[0040] The method for coupling the magnetic south pole 262, the coupling portion 266, and the magnetic north pole 264 is not particularly limited, and they may be coupled, for example, by magnetic attraction or by bonding with an adhesive.

[0041] The volume fraction of the coupling region 266 in the magnet composite body 26 is preferably 40% to 70%, and more preferably 50% to 60%. In this case, the rated power per unit of magnet quantity is increased.

[0042] Now, the outer stator 3 of the motor generator 1 according to the present invention will be described. The outer stator 3 contains several teeth 32. In the Fig. In the embodiment shown in Figure 1, the outer stator 3 includes 12 teeth 32.

[0043] The teeth 32 serve as iron cores of an armature coil. In the outer stator 3, the plurality of teeth 32 are arranged in a radial configuration.

[0044] Coils (not shown) are wound around the teeth 32. The winding method for the coils includes distributed winding and concentrated winding. The coil is capable of exerting a rotating magnetic field on the inner rotor 2, and in addition, a change in the magnetic flux due to the rotation of the inner rotor 2 is dissipated as current.

[0045] The composite magnet body according to the present invention has a design in which a coupling region made of a soft magnetic material is inserted between a magnet south pole and a magnet north pole. Therefore, the composite magnet body according to the present invention can dissipate a magnetic moment contained in the magnet to the outside without leakage. In particular, when the magnetic path of the magnetic circuit corresponds to the magnet orientation, a large magnetic flux can be generated within the magnetic circuit.In the magnetic composite body according to the present invention, a magnetic torque generated between the stator and the rotor can be increased when, in the case where the axes of easy magnetization are aligned in arc shape and in concentric circles, the polar anisotropic magnet is arranged in the rotor such that the shape of the magnetic lines of force from the stator substantially coincides with orientations of the axes of easy magnetization by optimizing the radii of curvature of the axes of easy magnetization in the alignment according to the shape of the magnetic lines of force from the stator.

[0046] The motor-generator according to the present invention can be used as any prime mover (“motor” in the narrow sense) that converts electrical energy into mechanical energy; as a prime mover (generator) that converts mechanical energy into electrical energy; and as a prime mover (motor-generator) that has both functions as a motor and a generator.

[0047] The rotor according to the present invention is preferably used as an inner rotor in the motor generator according to the present invention, and can also be used as a drive motor. Examples

[0048] The present invention will now be described with reference to examples.

[0049] First, several magnet composite bodies were prepared, each with a surface created by cutting a cylinder and cutting out a part of the cylinder in a direction parallel to the axis of the cylinder as in Fig. 2A shown obtained shape, and with different presence fractions of the coupling regions.

[0050] In particular, as in Fig. As shown in Figure 3, several magnetic composite bodies were manufactured in which angles "a" and "b" were varied at intervals of 5° within a range of 5° to 75°, where angle "a" represents an outer circumference of the coupling region and angle "b" represents an inner circumference thereof, with a point as the center indicating an axis ω. The volume fraction of the coupling region in the magnetic composite body varied within a range of 6.9% to 90.3%.

[0051] Next, the Fig. A permanent magnet motor-generator shown in Figure 1 was fabricated by arranging n pieces of the composite magnet bodies on an outer peripheral side of the rotating member. Then, the permanent magnet motor-generator, mounted on a drive motor, was driven. The torque was measured under constant current conditions, an induced voltage correlated with the rotational speed was measured, and an induced voltage constant was calculated from the measured induced voltage. After calculating the rated rotational speed under constant voltage conditions from the induced voltage constant, the rated power was calculated from the measured torque and the rated rotational speed. The results are in Fig. 4 shown. The horizontal axis (X-axis) in Fig. 4 means a volume fraction of the coupling area on the magnet composite body. Out of Fig.4, it was found that the rated power was high when the volume fraction of the coupling region on the magnet composite body was approximately 70% or less, and the rated power decreased sharply when the volume fraction of the coupling region on the magnet composite body was more than 70%.

[0052] The present invention is based on Japanese Patent Application No. 2023-105055, filed on June 27, 2023, the contents of which are hereby incorporated by reference. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2018-38162 A

[0004] JP 2023-105055

[0052]

Claims

[1] Rotor (2), with: 2n (n≥1) magnetic poles; a shaft (22); a rotating member (24) formed from a non-magnetic material and connected to the shaft (22); and n magnetic composite bodies (26), each having a curved shape and connected to an outer peripheral side of the rotary member (24) in such a way that they represent a protrusion towards the shaft (22), the magnetic composite bodies (26) including a magnetic south pole (262), which is an anisotropic magnet acting as an S-pole on the outer peripheral surface of the rotating member (24), and a magnetic north pole (264), which is an anisotropic magnet acting as an N-pole on the outer peripheral surface of the rotating member (24), and a coupling region (266) formed of a soft magnetic material, wherein the coupling region (266) is inserted between the magnetic south pole (262) and the magnetic north pole (264), and wherein, when the coupling portion (266) is inserted in a left-right direction between the magnetic south pole (262) and the magnetic north pole (264), the bent shape is bilaterally symmetrical, and a shape of the coupling portion (266) is also bilaterally symmetrical. [2] Rotor (2) according to claim 1, with a volume fraction of the coupling region (266) in the magnet composite body of 40% to 70%. [3] The rotor (2) according to claim 1 or 2, wherein each of the magnetic south poles (262) and the magnetic north poles (264) is aligned such that an axis of easy magnetization forms an arc shape, the arc is part of a concentric circle, and a center point C1 of an arc of the magnetic south pole (262) and a center point C2 of an arc of the magnetic north pole (264) are arranged at bilaterally symmetrical positions or coincide with each other. [4] Rotor (2) according to one of claims 1 to 3, wherein a surface S α which comes into contact with the coupling region (266) in the magnet south pole (262), has the same shape as a surface S1 which comes into contact with the magnet south pole (162) in the coupling region (266), or the surface S α smaller than the surface S1 and contained in the surface S1, and where a surface S βwhich comes into contact with the coupling region (266) in the magnetic north pole, has the same shape as a surface S2 which comes into contact with the magnetic north pole in the coupling region (266), or the surface S β smaller than the surface S2 and is contained in the surface S2. [5] Permanent magnet motor generator (1) with: the rotor (2) according to claim 1 or 2 as the inner rotor; and an outer stator (3) with a central through-hole into which the inner rotor (2) is inserted. [6] A permanent magnet motor generator (1) according to claim 5, wherein the outer stator (3) comprises: a plurality of teeth (32) serving as an iron core of an armature coil and arranged in a radial shape; and coils wound around the teeth (32).

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