Permanent magnet rotor and rotary electric machine

Abstract

To enable positioning of a magnet when the magnet is inserted even if a neodymium magnet is replaced with a ferrite magnet, and to secure structural strength and torque performance.SOLUTION: A permanent magnet rotor 100 includes a rotor shaft 101, two permanent magnets 110 arranged in line symmetry with respect to an M axis, and a rotor core 120 in which a flux barrier band 130 formed in a convex shape toward a rotation center axis is formed. The bridge includes at least one center bridge 131 formed along the direction of the M-axis. Each of the two permanent magnets 110 is in contact with the rotator core 120 at least at one of two corners at both ends of the radially outer short side 111c that is in contact with the outer holding protrusion 138 of the storage portion and the radially inner short side 111d that is a contact portion in contact with the edge portion of the magnet storage portion 133.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a permanent magnet rotor and a rotating electric machine. [Background technology]

[0002] In recent years, motors for trains and automobiles have begun to use permanent magnets containing rare earth elements such as neodymium. The permanent magnets are arranged in one or more layers in a V- or U-shape at each magnetic pole. This configuration creates magnetic salience, which combines magnetic torque and reluctance torque to generate large torque.

[0003] Fig. 14 is a partial cross-sectional view showing an example of the configuration of a permanent magnet rotor of a conventional rotating electric machine, illustrating one magnetic pole between two R axes in the circumferential direction in a cross section perpendicular to the central axis of rotation CL of the permanent magnet rotor.

[0004] Two neodymium magnets 41 are arranged symmetrically with respect to the M axis, which extends radially from the central axis of rotation CL. The two neodymium magnets 41 are oriented so that the side closer to the M axis faces radially inward, i.e., they are arranged so that the entire magnet is convex radially inward. Note that the neodymium magnet here refers to a neodymium-containing magnet to which a heavy rare earth element such as terbium or dysprosium has been added. On the other hand, a neodymium-containing magnet without the addition of a heavy rare earth element will be referred to as a neodymium magnet without a heavy rare earth element.

[0005] The rotor core 50 is attached to the radially outer side of the rotor shaft 101. The rotor core 50 includes magnet storage holes 51 that store two neodymium magnets 41, and has a flux barrier band 50f that extends from one side of the outer circumferential surface 50x to the other and is formed to have a convex shape on the radially inner side.

[0006] Two protrusions, an outer holding protrusion 52 and an inner holding protrusion 54, are formed on the edge of the rotor core 50 that forms the magnet storage hole 51 in order to hold the neodymium magnet 41.

[0007] The outer retaining protrusions 52 are protrusions that resist the centrifugal force that acts on the neodymium magnets 41 when the permanent magnet rotor rotates. The outer retaining protrusions 52 also function to position the neodymium magnets 41 when they are stored in the magnet storage holes 51 of the rotor core 50 during assembly. The inner retaining protrusions 54, together with the outer retaining protrusions 52, also function to position the neodymium magnets 41 when they are stored in the magnet storage holes 51 of the rotor core 50 during assembly. In other words, because centrifugal force does not act on the neodymium magnets 41, the inner retaining protrusions 54 are provided only for the purpose of positioning during the assembly process.

[0008] Here, in rotor core 50, outer support projection stress relief portions 53, which are recesses for relieving stress concentration, are formed at the bases of outer support projections 52. Similarly, inner support projection stress relief portions 55, which are recesses for relieving stress concentration, are formed at the bases of inner support projections 54.

[0009] The rotor core 50 is divided by the flux barrier bands 50f into a radially outer fan-shaped portion and a radially inner portion. During operation of the rotating electric machine, the centrifugal force acting on this fan-shaped portion and the neodymium magnets 41 is borne by the top bridge 50b and the center bridge 50c. Because the centrifugal force acts in the radial direction, it is mainly borne by the center bridge 50c.

[0010] 14, the center bridge 50c has a straight portion in the center, and the root portions (base portions) on the inner and outer radial sides are gradually thickened, for example, in an arc shape, thereby alleviating stress concentration at the root portions. For this reason, an inner space 56 is formed radially inside the magnet storage hole 51, communicating with the magnet storage hole 51.

[0011] Regarding rare earths, it is desirable to reduce the amount of magnets containing these elements due to the depletion of scarce resources. One possible way to achieve this is to use magnets such as ferrite magnets, which have low magnetic force but contain relatively small amounts of scarce resources. Ferrite magnets have a low residual magnetic flux density Br, about one-third that of current neodymium magnets. For this reason, in order to use ferrite magnets to achieve performance equivalent to that of current neodymium magnets, the magnet width must be made extremely large.

[0012] In a rotor that uses both neodymium magnets and ferrite magnets, one way to replace as many neodymium magnets as possible with ferrite magnets is to make the V-shape angle acute and extend the flux barrier band that houses the magnets longitudinally.

[0013] 15 is a partial cross-sectional view showing a reference example in which a ferrite magnet 42 is introduced into a permanent magnet rotor of a conventional rotating electric machine. This shows the case in which a ferrite magnet 42 is provided instead of the neodymium magnet 41 shown in FIG.

[0014] The ferrite magnet 42 shown in Figure 15 has larger dimensions in both the longitudinal and thickness directions than the neodymium magnet 41 shown in Figure 14 in order to ensure the total amount of magnetic flux. Specifically, the remanence Br of a ferrite magnet at 80°C is approximately one-third that of a neodymium magnet, and the minimum coercivity Hcj under severe temperature conditions from the perspective of demagnetization is approximately one-half. Considering that the coercivity of neodymium magnets decreases at high temperatures, while that of ferrite magnets decreases at low temperatures, the severe temperature conditions for neodymium magnets are defined as 150°C and -40°C, respectively. Therefore, to compensate for the decrease in remanence Br, the area through which magnetic flux flows, and therefore the longitudinal length, must be approximately three times larger. Furthermore, to compensate for the decrease in coercivity Hcj, the thickness direction, i.e., the length of the short side of the cross section of the ferrite magnet 42, must be approximately doubled.

[0015] The portion of the rotor core 50 on the R-axis side serves as a path for the magnetic flux from the stator winding. Therefore, the width of the magnetic path along the R-axis must be maintained. As a result, the ferrite magnets 42 extend radially inward.

[0016] This allows the ferrite magnets 42 to be loaded, but the center bridge is positioned radially inward, and the diameter of the inner part is smaller than the rotor yoke, i.e., the flux barrier band including the magnet storage hole. As a result, as will be described below, stress concentration around the center bridge and the edge 50z of the rotor yoke becomes a problem.

[0017] Even in the case of ferrite magnet 42, two protrusions, an outer retaining protrusion 52 and an inner retaining protrusion 54, are formed on edge 50z of rotor core 50 that forms magnet storage hole 51. In addition, outer retaining protrusion stress relief portion 53 and inner retaining protrusion stress relief portion 55, which are recesses for alleviating stress concentration, are formed at the bases of outer retaining protrusion 52 and inner retaining protrusion 54, respectively.

[0018] Accordingly, the flux barrier band 50g shown in FIG. 15 is more convex radially inward than the flux barrier band 50f for the neodymium magnet 41 shown in FIG. 14. As a result, the area of ​​the radially outer fan-shaped portion defined by the flux barrier band 50g is larger. In other words, the weight of the fan-shaped portion of the rotor core 50 and the ferrite magnets 42 is greater than in the case shown in FIG. 14. As a result, the centrifugal force acting on the fan-shaped portion and the ferrite magnets 42 increases.

[0019] This centrifugal force is borne by the top bridge 50b and the center bridge 50c. Because the centrifugal force acts in the radial direction, it must be borne mainly by the center bridge 50c.

[0020] In terms of structural strength, this can be addressed by making the center bridge 50c thicker. However, from an electromagnetic standpoint, making the center bridge 50c thicker is not desirable because it leads to a decrease in the performance of the rotating electrical machine. [Prior art documents] [Patent documents]

[0021] [Patent Document 1] Patent No. 5443778 [Patent Document 2] Patent No. 5730736 [Patent Document 3] US Patent Application Publication No. 2022 / 0190657 [Patent Document 4] Patent No. 6385715 [Patent Document 5] Patent No. 6319973 Summary of the Invention [Problem to be solved by the invention]

[0022] As mentioned above, the inner retaining protrusions 54 are formed along with the outer retaining protrusions 52 to position the ferrite magnet 42 during assembly of the permanent magnet rotor. In the case of the ferrite magnet 42 shown in FIG. 15, the distance between the radially inner root of the center bridge 50c and the inner retaining protrusion 54 is short. For this reason, the edge 50z of the inner space 56 between the inner retaining protrusion 54 and the center bridge 50c cannot be formed as an arc with a large radius of curvature. This makes it impossible to alleviate stress concentration, and combined with the increased centrifugal force acting on the center bridge 50c for the reasons mentioned above, the stress at the edge 50z becomes significantly higher.

[0023] If the range of the inner space 56 is expanded radially inward in an attempt to avoid this, the radial thickness Lz of the rotor yoke, which is a circumferentially continuous portion on the radially outer side of the rotor shaft 101, becomes thinner. In this case, the centrifugal force of the rotor core 50 and the ferrite magnets 42 becomes significant. This centrifugal force significantly deforms the rotor yoke around the center bridge 50c, bending it radially outward. As a result, bending stress acts on the edge 50z of the rotor core 50 facing the inner space 56, causing excessive stress on the edge 50z.

[0024] In the case of a configuration in which the inner retaining projection is provided on the center bridge 50c, stress concentration occurs at the joint between this inner retaining projection and the center bridge 50c, and it is not easy to create a shape that avoids stress concentration.

[0025] As described above, it is necessary to establish a configuration that allows positioning when inserting magnets in the assembly of a permanent magnet rotor without compromising either the structural strength or torque performance.

[0026] The problem that the present invention aims to solve is to provide a permanent magnet rotor and a rotating electric machine that can ensure both structural strength and torque performance while allowing magnet positioning when inserting the magnets, even when all or part of the neodymium magnets are replaced with ferrite magnets. [Means for solving the problem]

[0027] In order to achieve the above-mentioned object, a permanent magnet rotor according to an embodiment of the present invention includes a rotor shaft extending in the axial direction of a central rotation axis; two permanent magnets extending in the axial direction and arranged in line symmetry with respect to an M-axis extending from the central rotation axis when viewed in a cross section perpendicular to the central rotation axis, the two permanent magnets having a rectangular cross-sectional shape consisting of an outer diameter long side, an inner diameter long side, an outer diameter short side, and an inner diameter short side; and a flux barrier band attached to the radial outside of the rotor shaft, which is divided equally in the circumferential direction and houses the two permanent magnets, includes a nonmagnetic region and a bridge, and extends from one side of the outer circumferential surface to the other side across the M-axis and is formed in a convex shape toward the central rotation axis. and a rotor core formed by connecting the bridges to the M-axis, wherein the bridges have at least one center bridge formed along the direction of the M-axis, and the non-magnetic region of the flux barrier band has a holding protrusion formed on the edge of a storage section that stores each of the two permanent magnets, the holding protrusion being formed so as to contact a portion of the outer diameter side short side of each of the two permanent magnets, and the portion where each of the two permanent magnets contacts the rotor core is the outer diameter side short side that contacts the holding protrusion of the storage section, and at least one of two corners at both ends of the inner diameter side short side that is an abutment portion that contacts the edge of the storage section or the center bridge. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a vertical cross-sectional view showing the configuration of a rotating electric machine according to a first embodiment. [Figure 2] 1 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a first embodiment. [Figure 3] 3 is a detailed partial cross-sectional view of part A in FIG. 2 showing the contact portion of the permanent magnet of the permanent magnet rotor according to the first embodiment. [Figure 4] 3 is a partial cross-sectional view showing part A in FIG. 2, illustrating a contact portion as a modified example of the permanent magnet of the permanent magnet rotor according to the first embodiment. [Figure 5] FIG. 3 is a partial cross-sectional view showing the configuration of a first modified example of the permanent magnet rotor according to the first embodiment. [Figure 6] FIG. 4 is a partial cross-sectional view showing the configuration of a second modified example of the permanent magnet rotor according to the first embodiment. [Figure 7] FIG. 10 is a partial cross-sectional view showing the configuration of a third modified example of the permanent magnet rotor according to the first embodiment. [Figure 8] FIG. 6 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a second embodiment. [Figure 9] FIG. 10 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a third embodiment. [Figure 10] FIG. 10 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a fourth embodiment. [Figure 11] FIG. 10 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a fifth embodiment. [Figure 12] FIG. 10 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a sixth embodiment. [Figure 13] FIG. 11 is a partial cross-sectional view showing the configuration of a permanent magnet rotor according to a seventh embodiment. [Figure 14] FIG. 10 is a partial cross-sectional view showing an example of the configuration of a permanent magnet rotor of a conventional rotating electric machine. [Figure 15] FIG. 10 is a partial cross-sectional view showing a reference example in which a ferrite magnet is introduced into a permanent magnet rotor of a conventional rotating electric machine. DETAILED DESCRIPTION OF THE INVENTION

[0029] A permanent magnet rotor and a rotating electric machine according to an embodiment of the present invention will be described below with reference to the drawings. Here, identical or similar parts are designated by common reference numerals, and duplicated explanations will be omitted. The following embodiment shows a case where neodymium magnets are replaced with ferrite magnets, but is not limited to this. In other words, the present invention can also be applied to conventional neodymium magnets.

[0030] [First embodiment] FIG. 1 is a vertical cross-sectional view showing the configuration of a rotating electrical machine 1 according to an embodiment.

[0031] The rotating electric machine 1 includes a permanent magnet rotor 100, a stator 10, a bearing 21, a bearing bracket 22, and a frame 23.

[0032] Permanent magnet rotor 100 has a rotor shaft 101 extending in a direction parallel to central axis of rotation CL (axial direction), a rotor core 120 attached to the radial outside of rotor shaft 101, and a plurality of permanent magnets 110 housed inside rotor core 120. Rotor core 120 is formed by laminating electromagnetic steel sheets 121. Note that while FIG. 1 shows an example in which rotor core 120 has a plurality of electromagnetic steel sheets 121, the present invention is not limited to this and can also be applied to a solid-type permanent magnet rotor in which the rotor shaft and rotor core are integrated.

[0033] The stator 10 has a stator core 11 disposed radially outside the rotor core 120 so as to surround the rotor core 120 with a gap therebetween, and a stator winding 15 wound around the stator core 11 .

[0034] The bearings 21 are arranged on both outsides of the rotor core 120 in the axial direction of the rotor shaft 101, and rotatably support the rotor shaft 101. The bearing brackets 22 statically support the respective bearings 21. The frame 23 is cylindrical, and both ends thereof are connected to the respective bearing brackets 22, and support the respective bearing brackets 22.

[0035] The permanent magnet rotor 100 has a rotor shaft 101 extending in the direction of the rotation axis, a rotor core 120 attached to the rotor shaft 101, and a plurality of permanent magnets 110.

[0036] Fig. 2 is a partial cross-sectional view showing the configuration of the permanent magnet rotor 100 according to the first embodiment. Fig. 2 shows one magnetic pole 102 sandwiched between two imaginary R axes extending from the central axis of rotation CL. At the circumferential center of the two R axes is an imaginary M axis extending from the central axis of rotation CL.

[0037] In a cross section perpendicular to the central axis of rotation CL, the ferrite magnets 111, which are two permanent magnets 110, are arranged line-symmetrically with respect to the M axis. The two ferrite magnets 111 are arranged in a direction that approaches the M axis as they move radially inward. That is, they are arranged in a convex shape that projects radially inward. Note that FIG. 2 shows an example in which the two ferrite magnets 111 have the same cross section and are arranged line-symmetrically with respect to the M axis, but this is not limiting. For example, the two ferrite magnets 111 may have different cross sections. Furthermore, even if the two ferrite magnets 111 have the same cross section, they may not be line-symmetric with respect to the M axis.

[0038] The flux barrier band 130 is formed from one side to the other of the outer circumferential surface 120x of the rotor core 120. The flux barrier band 130 has magnet storage portions 133 that store the two ferrite magnets 111, a center bridge 131, and two top bridges 132. The flux barrier band 130 is formed in a radially inward convex shape, in other words, in a V-shape or a U-shape.

[0039] Although the present embodiment illustrates an example in which the flux barrier band 130 has two top bridges 132, the flux barrier band 130 may not have the top bridges 132. That is, the flux barrier band 130 may have an opening on the outer circumferential surface 120x of the rotor core 120. The same applies to the following embodiments.

[0040] An inner space 134 is formed radially inward of the magnet storage portion 133 and communicates with the magnet storage portion 133. The two inner spaces 134 form a center bridge 131 along the M axis. The center bridge 131 extends in a direction along the M axis, and its width increases radially inward and radially outward. Correspondingly, the two inner spaces 134 also have radial extension portions 135 that extend in the direction of the M axis, i.e., radially outward.

[0041] An outer space 137 is formed radially outside the magnet storage portion 133 and communicates with the magnet storage portion 133. Between each outer space 137 and the outer peripheral surface 120x of the rotor core 120, each top bridge 132 is formed.

[0042] The cross-sectional shape of each of the two ferrite magnets 111 is rectangular. The four sides of this rectangle are referred to as the outer diameter long side 111a, the inner diameter long side 111b, the outer diameter short side 111c, and the inner diameter short side 111d. The ferrite magnets 111 are magnetized in a direction perpendicular to the long sides.

[0043] There is a step between the radially inner edge of the magnet storage portion 133 and the radially inner edge of the outer space 137, forming an outer holding protrusion 138. The outer diameter side short side 111c of the ferrite magnet 111 is in contact with the outer holding protrusion 138. The ferrite magnet 111 is restrained from moving radially outward by the outer holding protrusion 138. There is a recess at the base of the outer holding protrusion 138, and an outer holding protrusion stress relief hole 139 is formed therein.

[0044] The corner formed by the outer diameter long side 111a and the inner diameter short side 111d of the ferrite magnet 111, in other words, one corner of the inner diameter short side 111d, abuts against the center bridge 131, and this part will be referred to as the abutment part 111u. The part enclosed by the dashed circle in Figure 2, which includes the abutment part 111u, will be described in detail with reference to Figure 3.

[0045] As described above, one corner of the inner diameter side short side 111d of the ferrite magnet 111 contacts the center bridge 131 as the abutment portion 111u, eliminating the need for the inner retaining protrusion 54. As a result, a gentle curve can be formed from the center bridge 131 to the inner edge of the rotor yoke, reducing stress concentration. Furthermore, using the ferrite magnet 111, it is possible to obtain the same performance and mechanical strength against centrifugal force as when using a conventional neodymium magnet.

[0046] FIG. 3 is a detailed partial cross-sectional view of part A in FIG. 2, showing the contact portion 111u of the permanent magnet 110 of the permanent magnet rotor 100 according to the first embodiment.

[0047] 3 shows, in a cross section perpendicular to the central axis of rotation CL, the corner formed by the outer diameter long side 111a and the inner diameter short side 111d of the ferrite magnet 111, in other words, the abutment portion 111u which is the contact portion between one corner of the inner diameter short side 111d and the center bridge 131. In other words, three-dimensionally, it shows the abutment portion 111u which is the contact portion between one ridge line of the inner diameter short side 111d and the center bridge 131.

[0048] The contact portion 111u is in contact with a surface corresponding to the linear portion of the center bridge 131, that is, a surface parallel to the M axis. A flat surface parallel to the surface of the center bridge 131 is formed on the contact portion 111u.

[0049] In this way, one corner of the inner diameter short side 111d is chamfered rather than formed as a ridge. As a result, the abutment portion 111u makes surface contact with the ridge rather than line contact, which prevents stress concentration at the corner of the magnet when inserting the magnet.

[0050] FIG. 4 is a partial cross-sectional view showing the portion A in FIG. 2, illustrating a contact portion 111v as a modified example of the permanent magnet 110 of the permanent magnet rotor 100 according to the first embodiment.

[0051] The difference between the contact portion 111v and the contact portion 111u is that the contact portion 111v is not flat, but has a curved surface that is convex on the outside, that is, on the surface side of the center bridge 131.

[0052] In the case of contact portion 111u, the opposing surfaces may not be parallel to each other depending on the precision of manufacturing and assembly, and in that case, contact may occur at one edge of the chamfered portion. In the contact portion 111u of the modified example, the contact state does not change even when the inclination changes, and because it has a gently curved surface, stress concentration at the corners of the magnet when it is inserted is still reduced.

[0053] FIG. 5 is a partial cross-sectional view showing the configuration of a first modification of the permanent magnet rotor according to the first embodiment.

[0054] In the flux barrier 130a in the first modification, a circumferential extension 136 extending from the inner space 134 toward the R-axis side in the circumferential direction is formed. Other than this point, it is the same as the first embodiment.

[0055] By forming the circumferential extension 136, the stress at the inner edge of the rotor yoke, particularly at the root portion radially inside the center bridge 131, is dispersed, stress concentration is reduced, and the strength can be improved. Also, the shortest distance w2 between the circumferential extension 136 and the R-axis is set to be longer than the shortest distance w1 between the outer holding projection stress relief hole 139 and the R-axis. This is because when the circumferential extension 136 is too close to the R-axis, excessive magnetic saturation occurs between the circumferential extension 136 and the R-axis in the magnetic path continuing from one R-axis to the other R-axis, thereby reducing the magnetic flux amount and the reluctance torque.

[0056] Therefore, by making the shortest distance w2 between the circumferential extension 136 and the R-axis longer than the shortest distance w1 between the outer holding projection stress relief hole 139 and the R-axis, that is, w1 < w2, and restricting the spread of the circumferential extension 136, the occurrence of magnetic saturation can be avoided and the torque performance can be maintained.

[0057] FIG. 6 is a partial cross-sectional view showing the configuration of a second modification of the permanent magnet rotor according to the first embodiment.

[0058] Similarly to the first modification, the flux barrier 130b in the second modification also has a circumferential extension 136 that extends circumferentially from the inner space 134 toward the R-axis. The second modification also has a contact portion 111v instead of the contact portion 111u. The contact portion 111v contacts the circumferential extension edge 126a, which is the boundary between the circumferential extension 136 and the rotor core 120. The contact portion 111v is a corner of the inner diameter short side 111d on the side opposite the contact portion 111u in a cross section perpendicular to the rotation center axis CL. In other words, the contact portion 111v is a corner formed by the inner diameter short side 111d and the inner diameter long side 111b. Other than this, the second modification is similar to the first embodiment.

[0059] In the second modified example, the circumferential extension 136 is also formed, thereby reducing stress concentration at the root portion on the radially inner side of the center bridge 131.

[0060] FIG. 7 is a partial cross-sectional view showing the configuration of a third modified example of the permanent magnet rotor according to the first embodiment.

[0061] The flux barrier 130c of the third modified example has the same contact portion 111u as in the first modified example and the same contact portion 111v as in the second modified example.

[0062] The third modification can also achieve the same effects as the first and second modifications.

[0063] [Second embodiment] FIG. 8 is a partial cross-sectional view showing the configuration of a permanent magnet rotor 100a according to the second embodiment.

[0064] This embodiment is a modification of the second modification of the first embodiment shown in FIG.

[0065] The flux barrier band 140 in the permanent magnet rotor 100a according to this embodiment is further formed with a central flux barrier 141. As a result, the flux barrier band 140 has two center bridges 142.

[0066] Conversely, the center bridge is divided into two center bridges 142. As a result, resistance to bending forces in the circumferential direction is strengthened. Furthermore, compared to a single center bridge, strength can be ensured with each bridge having a width that is less than half, which reduces leakage magnetic flux.

[0067] In this way, it is possible to provide an alternative variation to the first embodiment while obtaining the same effects as the first embodiment. This also applies to the third to sixth embodiments described below.

[0068] [Third embodiment] FIG. 9 is a partial cross-sectional view showing the configuration of a permanent magnet rotor 100b according to the third embodiment.

[0069] This embodiment is a modification of the second embodiment shown in FIG.

[0070] In the permanent magnet rotor 100b according to this embodiment, each permanent magnet is divided into a ferrite magnet 111 and an outer permanent magnet 112, which are arranged in a curved surface shape.

[0071] The flux barrier band 150 in the permanent magnet rotor 100b according to this embodiment further includes an intermediate bridge 152 and an outer ferrite magnet storage portion 153. In addition, in a cross section perpendicular to the central axis of rotation CL, the flux barrier band 150 is formed in a curved shape compared to the flux barrier band 140.

[0072] [Fourth embodiment] FIG. 10 is a partial cross-sectional view showing the configuration of a permanent magnet rotor 100c according to a fourth embodiment.

[0073] This embodiment is a modification of the third embodiment, in which an outer neodymium magnet 113 is disposed on the outer side of the ferrite magnet 111.

[0074] [Fifth embodiment] FIG. 11 is a partial cross-sectional view showing the configuration of a permanent magnet rotor 100d according to a fifth embodiment.

[0075] This embodiment is a modification of the fourth embodiment. That is, in addition to the configuration of the fourth embodiment, a flux barrier band 170 is further formed on the radially outer side. The flux barrier band 170 houses a neodymium magnet 114.

[0076] [Sixth embodiment] FIG. 12 is a partial cross-sectional view showing the configuration of a permanent magnet rotor 100e according to a sixth embodiment.

[0077] This embodiment is a modification of the fifth embodiment. Instead of the radially outer flux barrier band 170 in the fifth embodiment, a storage hole for storing an outer layer central ferrite magnet 115 is further added in the circumferential center.

[0078] [Seventh embodiment] FIG. 13 is a partial cross-sectional view showing the configuration of a permanent magnet rotor 100f according to the seventh embodiment.

[0079] This embodiment is a modification of the sixth embodiment. In this embodiment, a flux barrier band 190 is formed instead of the radially inner flux barrier band 160 in the sixth embodiment. Also, an outer flux barrier band 191 is formed instead of the radially outer flux barrier band 180 in the sixth embodiment.

[0080] The flux barrier band 190 is filled with a ferrite magnet 111, a second permanent magnet 116, and an outer neodymium magnet 113, arranged radially from the inside out. The second permanent magnet 116 is a neodymium magnet that does not contain heavy rare earth elements. The center of the outer flux barrier band 191 is also filled with a second permanent magnet 117, which is a neodymium magnet that does not contain heavy rare earth elements. According to the embodiments described above, it is possible to provide a permanent magnet rotor and a rotating electric machine that can ensure both structural strength and torque performance while allowing the magnets to be positioned when inserted, even if all or part of the neodymium magnets are replaced with ferrite magnets.

[0081] [Other embodiments] Although the embodiments of the present invention have been described above, they are presented as examples and are not intended to limit the scope of the invention. Furthermore, features of each embodiment may be combined. Furthermore, the embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. The embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. [Explanation of symbols]

[0082] 1... rotating electric machine, 10... stator, 11... stator core, 15... stator winding, 21... bearing, 22... bearing bracket, 23... frame, 30... permanent magnet rotor, 41... neodymium magnet, 42... ferrite magnet, 50... rotor core, 50c... center bridge, 50f, 50g... flux barrier band, 50x... outer surface, 50z... edge, 51... magnet storage hole, 52... outer retaining protrusion, 53... outer retaining protrusion stress relief hole, 54... inner retaining protrusion, 55... inner Retaining projection stress relief hole, 56... inner space, 100, 100a, 100b, 100c, 100d, 100e... permanent magnet rotor, 101... rotor shaft, 102... magnetic pole, 110... permanent magnet, 111... ferrite magnet, 111a... outer diameter side long side, 111b... inner diameter side long side, 111c... outer diameter side short side, 111d... inner diameter side short side, 111u, 111v... abutment portion, 112... outer ferrite magnet, 113... outer neodymium magnet, 114... outer layer neodymium magnet, 1 15... outer layer central ferrite magnet, 116, 117... second permanent magnet, 120... rotor core, 120x... outer peripheral surface, 126a... circumferential extension edge, 130... flux barrier band, 131... center bridge, 132... top bridge, 133... magnet storage section, 134... inner space, 135... radial extension, 136... circumferential extension, 137... outer space, 138... outer retaining protrusion, 139... outer retaining protrusion stress relaxation hole, 140... flux barrier band 141...central flux barrier, 142...center bridge, 150, 150a...flux barrier band, 152...intermediate bridge, 153...outer ferrite magnet housing, 160...flux barrier band, 153...outer ferrite magnet housing, 163...outer ferrite magnet housing, 170, 180...outer flux barrier band, 190...flux barrier band, 191...outer flux barrier band, CL...rotation center axis

Claims

1. a rotor shaft extending in the axial direction of the central rotation axis; two permanent magnets extending in the axial direction, and arranged symmetrically with respect to an M axis extending from the rotation center axis when viewed in a cross section perpendicular to the rotation center axis, the two permanent magnets having a rectangular cross-sectional shape consisting of an outer diameter long side, an inner diameter long side, an outer diameter short side, and an inner diameter short side; a rotor core attached to the radially outer side of the rotor shaft, accommodating two of the permanent magnets in magnetic poles equally divided in the circumferential direction, including a nonmagnetic region and a bridge, and having a flux barrier band formed in a convex shape toward the central axis of rotation, extending from one side of the outer circumferential surface to the other side across the M axis; A permanent magnet rotor comprising: The bridge has at least one center bridge formed along the direction of the M axis, a holding protrusion is formed on an edge of a housing portion in the non-magnetic region of the flux barrier band that houses each of the two permanent magnets, the holding protrusion being formed so as to contact a part of the outer diameter side short side of each of the two permanent magnets; The portions of the two permanent magnets that come into contact with the rotor core are at least one of the outer diameter side short side that comes into contact with the holding protrusion of the storage section and two corners at both ends of the inner diameter side short side that is an abutment portion that comes into contact with the edge of the storage section or the center bridge. A permanent magnet rotor characterized by:

2. 2. The permanent magnet rotor according to claim 1, wherein the two permanent magnets are ferrite magnets.

3. 2. The permanent magnet rotor according to claim 1, wherein the contact portion has a flat surface or an outwardly convex curved surface.

4. an R-axis is an axis that is a boundary between the magnetic poles and extends from the rotation center axis; At least one of the center bridges has a root portion on the inside in the radial direction, and a circumferential extension portion, which is a nonmagnetic region, is formed on the inside in the radial direction of the edge portion along the long side of the inner diameter, the circumferential extension portion extending along the extending direction of the long side of the inner diameter, the shortest distance between the circumferential extension and the R-axis is greater than the shortest distance between the flux barrier band and the R-axis; 2. The permanent magnet rotor according to claim 1.

5. 2. The permanent magnet rotor according to claim 1, wherein at least one of the center bridges has two bridges.

6. 2. The permanent magnet rotor according to claim 1, wherein a second permanent magnet is disposed adjacent to each of the two permanent magnets in the radial direction and on the outer side thereof in the longitudinal direction of the flux barrier band.

7. 7. The permanent magnet rotor according to claim 6, wherein the second permanent magnet is a ferrite magnet or a neodymium magnet.

8. 7. The permanent magnet rotor according to claim 6, wherein third permanent magnets are arranged adjacent to the radially outer side of each of the second permanent magnets in the longitudinal direction of the flux barrier band, the permanent magnets being ferrite magnets, the second permanent magnets being neodymium magnets containing no heavy rare earth elements, and the third permanent magnets being neodymium magnets containing heavy rare earth elements.

9. 7. The permanent magnet rotor according to claim 6, wherein a second flux barrier band for accommodating a fourth permanent magnet is formed radially outside the flux barrier band.

10. A permanent magnet rotor according to any one of claims 1 to 9; a stator having a stator core disposed radially outside the rotor core so as to surround the rotor core, and a stator having a stator winding wound around the stator core; A rotating electric machine comprising:

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