Rotor and rotating electric machine

Abstract

To provide a rotor and a rotary electric machine that can be expected to enhance centrifugal force strength by simple countermeasures.SOLUTION: One core sheet 30 comprises, circumferentially alternately disposed manner: pairs of first magnet-accommodating-through-openings 31 each having a connection partition 31c in the middle of a V-shape thereof and corresponding to respective magnet accommodating openings of a rotor core; and second accommodating-through-openings 32 with no connection partition. When being laminated as a rotor core, the core sheets 30 of the same configuration are used, and the core sheets 30 are laminated with the first magnet-accommodating-through-openings 31 and the second magnet-accommodating-through-openings 32 mixedly arranged, respectively, at a first position and a second position, circumferentially alternately displaced by 45° for each sheet in one configuration of magnet accommodating openings.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an embedded magnet type rotor and a rotating electric machine. [Background technology]

[0002] Rotating electric machines using interior permanent magnet (IPM) rotors are well known. Interior permanent magnet rotors have permanent magnets embedded inside a rotor core, and are configured to obtain reluctance torque from an outer core portion located radially outward of the permanent magnets in addition to magnet torque from the permanent magnets.

[0003] In such embedded magnet rotors, when the permanent magnets are folded in a V- or U-shape, convex toward the inside in the radial direction, as viewed in the axial direction (see, for example, Patent Document 1), it is possible to increase the size of the magnet surface of the permanent magnet in contact with the outer core portion and the outer core portion itself. In other words, this is expected to increase the torque of the rotating electric machine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-85779 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, on the other hand, since magnet accommodating holes for accommodating permanent magnets are formed in the rotor core, it is difficult to set the position and shape of the connecting portion that connects the outer core portion to the main body portion of the rotor core. This is because the connecting portion is also a portion where magnetic flux leakage occurs. Therefore, if the connecting portion is narrowed, the connecting portion that supports the outer core portion becomes structurally weak, leading to a decrease in the centrifugal force strength of the outer core portion. This becomes more noticeable as the outer core portion becomes larger in order to increase torque. The inventor of the present invention has been considering whether such a problem can be solved by a simple solution. An object of the present invention is to provide a rotor and a rotating electric machine that can be expected to improve centrifugal force strength by a simple solution. [Means for solving the problem]

[0006] The rotor that solves the above problem is a rotor (20) comprising a rotor core (22) formed by stacking a plurality of core sheets (30) and having a plurality of magnet accommodating holes (24) that form a folded shape that convexly faces radially inward, and permanent magnets (23) that are embedded in the magnet accommodating holes of the rotor core, in which the core sheet is provided with a mixture of a first magnet through hole (31) having a connecting portion (31c, 61) that connects the inner peripheral edge portions that face each other in the hole width direction at a midpoint of the folded shape that corresponds to the magnet accommodating holes, and a second magnet through hole (32) that does not have the connecting portion (31c, 61), and the rotor core is formed by stacking the core sheets using the same configuration so that the first magnet through hole and the second magnet through hole are mixed in the configuration of one of the magnet accommodating holes of the rotor core.

[0007] The rotating electric machine that solves the above problem is a rotating electric machine (M) including a rotor core (22) formed by laminating a plurality of core sheets (30) and having a plurality of magnet accommodating holes (24) that form a folded shape that is convex inward in the radial direction, a rotor (20) including permanent magnets (23) that are embedded in the magnet accommodating holes of the rotor core, and a stator (10) that applies a rotating magnetic field to the rotor, wherein the core sheets are folded at intermediate positions of the folded shape that correspond to the magnet accommodating holes. A first magnet through hole (31) having a connecting portion (31c, 61) connecting inner peripheral edges facing each other in the hole width direction and a second magnet through hole (32) without the connecting portion (31c, 61) are mixed in one core sheet, and the rotor core is constructed by stacking the core sheets having the same configuration so that the first magnet through hole and the second magnet through hole are mixed in the configuration of one of the magnet accommodating holes of the rotor core.

[0008] According to the rotor and rotating electric machine, in one core sheet, a first magnet through hole having a connecting portion at a midpoint of a folded shape corresponding to the magnet housing hole of the rotor core and a second magnet through hole without a connecting portion are mixed. Then, when stacking as a rotor core, the rotor core is stacked using core sheets of the same configuration so that the first magnet through hole and the second magnet through hole are mixed in the configuration of one magnet housing hole. In other words, the outer core part of the rotor core located radially outward from the permanent magnet is supported by the common part of the rotor core at three or more points, including the newly added connecting portion of the first magnet through hole, in addition to the two connecting portions on the outer side of its own radially outer end portion, which are necessarily provided due to the configuration of the magnet housing hole due to the embedded magnet type rotor. Therefore, it is possible to improve the centrifugal force strength of the outer core part. Moreover, it is possible to realize it by a simple measure of only preparing one type of core sheet. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a configuration diagram of a rotating electric machine having an embedded magnet type rotor according to one embodiment. [Diagram 2]FIG. [Diagram 3] FIG. [Figure 4] 13(a) and (b) are plan views of a core sheet used in a rotor in the same configuration. [Diagram 5] 4 is a diagram illustrating the characteristics of the rotor in the embodiment; FIG. [Figure 6] 4 is a diagram illustrating the characteristics of the rotor in the embodiment; FIG. [Figure 7] FIG. 11 is a perspective view of a rotor in a modified example. [Figure 8] FIG. 11 is a perspective view of a rotor in a modified example. [Figure 9] FIG. 11 is a perspective view of a rotor in a modified example. [Figure 10] FIG. 11 is a perspective view of a rotor in a modified example. [Figure 11] FIG. 11 is a plan view of a rotor in a modified example. [Figure 12] Cross-sectional view taken along line XII-XII in Figure 11. [Figure 13] Cross-sectional view taken along line XIII-XIII in FIG. [Figure 14] 13A and 13B are plan views of a core sheet used in a rotor in the modified example. [Figure 15] FIG. 11 is a plan view of a rotor in a modified example. [Figure 16] Cross-sectional view taken along line XVI-XVI in Figure 15. [Figure 17] FIG. 11 is a cross-sectional view of a rotor in a modified example. [Figure 18] FIG. 11 is a plan view of a rotor in a modified example. [Figure 19] FIG. 11 is a plan view of a core sheet in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the rotor and the rotating electric machine will be described below. 1, a rotating electric machine M of this embodiment is configured as an embedded magnet type brushless motor. The rotating electric machine M includes a substantially annular stator 10 and a substantially cylindrical rotor 20 rotatably disposed in the radial inner space of the stator 10.

[0011] The stator 10 includes a stator core 11 having a substantially circular ring shape. The stator core 11 is made of a magnetic metal material, for example, a laminate of a plurality of electromagnetic steel sheets. The stator core 11 has 12 teeth 12 extending radially inward and arranged at equal intervals in the circumferential direction in this embodiment. The teeth 12 have the same shape as each other. The radially inner end of the teeth 12, which is the tip portion, is substantially T-shaped, and the tip surface 12a is an arc shape following the outer circumferential surface of the rotor 20. The windings 13 are wound around the 12 teeth 12 by concentrated winding. That is, the number of magnetic poles of the stator 10 is "12". The windings 13 are connected in a three-phase manner, and function as U-phase, V-phase, and W-phase, respectively, as shown in FIG. 1. When power is supplied to the windings 13, a rotating magnetic field for rotating the rotor 20 is generated in the stator 10. In the stator 10 as described above, the outer peripheral surface of the stator core 11 is fixed to the inner peripheral surface of the housing 14 .

[0012] The rotor 20 includes a rotating shaft 21, a substantially cylindrical rotor core 22 into whose center the rotating shaft 21 is fitted, and eight permanent magnets 23 in this embodiment that are embedded inside the rotor core 22. In other words, the rotor 20 has eight magnetic poles. The rotor 20 is rotatably disposed with respect to the stator 10 with the rotating shaft 21 supported by a bearing (not shown) provided in the housing 14.

[0013] As shown in Fig. 2, the rotor core 22 has magnet accommodating holes 24 for accommodating the permanent magnets 23. In this embodiment, eight magnet accommodating holes 24 are provided at equal intervals in the circumferential direction of the rotor core 22. Each magnet accommodating hole 24 has a generally V-shaped folded shape that protrudes radially inward, that is, a shape in which radially inner ends of a pair of straight portions 24a are connected by a bent portion 24b. A radially outer end 24c of the straight portions 24a of the magnet accommodating hole 24 is located near the outer circumferential surface 22a of the rotor core 22. The bent portion 24b is located near a shaft insertion hole 22b in the center of the rotor core 22, into which the rotating shaft 21 is inserted.

[0014] The magnet accommodating holes 24 are set so that the hole width of a pair of straight portions 24a (corresponding to the thickness Wm of straight portions 23a of permanent magnet 23) is constant, and the hole width of bent portions 24b (corresponding to the thickness Wm1 of bent portions 23b of permanent magnet 23) gradually becomes narrower than that of straight portions 24a. The magnet accommodating holes 24 are provided over the entire axial direction of the rotor core 22. The magnet accommodating holes 24 are of substantially similar configuration, but there are two types, a first embodiment magnet accommodating hole 24α and a second embodiment magnet accommodating hole 24β, which differ in slight respects (details will be described later).

[0015] As shown in Fig. 3, the rotor core 22 is formed by stacking a plurality of core sheets 30 made of electromagnetic steel sheets in the direction of the axis L1. The individual core sheets 30 have the same configuration as shown in Fig. 4(a). The core sheet 30 shown in Fig. 4(b) appears to have a different shape at first glance, but is actually arranged at a second position rotated 45°, which is the amount of one magnet accommodating hole 24, in other words, one magnetic pole, from the first position shown in Fig. 4(a). The core sheet 30 is formed with a mixture of two types of magnet through holes 31 and 32 to form the magnet accommodating holes 24 of the rotor core 22 in two forms.

[0016] The first and second magnet through holes 31, 32 are each formed in a substantially V-shaped folded shape that is convex toward the inside in the radial direction, that is, a shape in which the radially inner ends of a pair of straight parts 31a, 32a are connected to each other by bent parts 31b, 32b. The first and second magnet through holes 31, 32 are different from each other in that the bent part 31b of the first magnet through hole 31 has a connecting part 31c, and the bent part 32b of the second magnet through hole 32 has a shape that does not have a connecting part such as the connecting part 31c. The connecting part 31c extends in the hole width direction of the first magnet through hole 31 and connects the inner peripheral edge parts facing each other in the same direction. The width Wb of the connecting part 31c is set to be equal to or less than the thickness t (see FIG. 3) of one core sheet 30. The side edge 31d of the connecting portion 31c has a uniform curved shape that narrows toward the center in the direction in which the connecting portion 31c itself extends. As an example, the curved shape of the side edge 31d is set to a radius of curvature that is approximately half the length of the connecting portion 31c in the direction in which the connecting portion 31c extends. Such first and second magnet through holes 31, 32 are alternately arranged every 45° in the circumferential direction in each core sheet 30.

[0017] In the process of stacking the core sheets 30 to configure the rotor core 22, in this embodiment, the core sheets 30 are stacked one by one so that the core sheets 30 arranged in the first position shown in Fig. 4(a) and the core sheets 30 arranged in the second position shown in Fig. 4(b) rotated by 45° are alternately stacked. That is, when configured as the rotor core 22, the magnet accommodating hole 24α of the first mode in which the first magnet through hole 31 having the connecting portion 31c at the bent portion 31b and the second magnet through hole 32 having no connecting portion at the bent portion 32b are alternated from the upper layer to the lower layer as shown in Fig. 2, and the magnet accommodating hole 24β of the second mode in which the second magnet through hole 32 having no connecting portion at the bent portion 32b and the first magnet through hole 31 having the connecting portion 31c at the bent portion 32b are alternated are configured. The magnet accommodating holes 24α and 24β of the first and second modes are configured such that the first and second magnet through holes 31 and 32 are arranged in the reverse order to each other.

[0018] That is, when configured as the rotor core 22, the outer core portion 25 described below, which is located radially outward of the permanent magnet 23 inside the V-shaped folded shape of the permanent magnet 23 provided in the magnet accommodating hole 24, is supported by the common portion 22x of the rotor core 22 at three points: two connecting portions 22d outside the radially outer ends 24c of the pair of straight portions 24a of the magnet accommodating hole 24, and the connecting portions 31c of the first magnet through holes 31 located in every other core sheet 30. Therefore, in addition to the two connecting portions 22d necessarily provided in the configuration of the magnet accommodating hole 24, the outer core portion 25 is supported at three points including the newly added connecting portion 31c located at the bent portion 24b, thereby improving the centrifugal force strength of the outer core portion 25.

[0019] In addition, the connecting parts 22d, 31c are provided at three locations for one outer core part 25, and the three connecting parts 22d, 31c are arranged in a well-balanced manner around the outer core part 25, contributing to stable support of the outer core part 25. In addition, by setting the three connecting parts 22d, 31c to be equal to or less than the thickness t of one core sheet 30, the magnetic flux leakage, which is a concern, is sufficiently reduced. Furthermore, the radial outer end 24c of the magnet accommodating hole 24 is provided with a protruding part 22e in which the inner corners of the V-shaped folded back shape protrude in a tapered shape. In other words, the radial outer end 24c of the magnet accommodating hole 24 is narrowed, and the length Lb of the outer connecting part 22d is made smaller than the hole width of the straight part 24a of the magnet accommodating hole 24 (corresponding to the thickness Wm of the straight part 23a of the permanent magnet 23). This also makes it possible to improve the centrifugal force strength of the outer core part 25.

[0020] 3, in the case of this embodiment in which the number of core sheets 30 is an odd number, the opening shape of the magnet accommodating holes 24 appearing on both the upper and lower axial end faces 22c of the rotor core 22 is the same. In the case in which the number of core sheets 30 is an even number, the opening shape of the magnet accommodating holes 24 appearing on the axial end faces 22c on both sides of the rotor core 22 will be either the shape of the magnet through holes 31, 32, which may be selected. In each magnet accommodating hole 24 configured in this manner, a permanent magnet 23 is provided in an embedded state.

[0021] In this embodiment, the permanent magnet 23 is a bonded magnet obtained by molding and solidifying a magnetic material obtained by mixing magnetic powder with resin. That is, the permanent magnet 23 is formed by using the magnet accommodating hole 24 of the rotor core 22 as a molding die, filling the magnet accommodating hole 24 with magnetic material before solidification without gaps by injection molding, and solidifying the magnet material in the magnet accommodating hole 24 after filling. Therefore, the hole shape of the magnet accommodating hole 24 becomes the outer shape of the permanent magnet 23. In this case, the magnetic material also flows between the connecting parts 31c provided in every other core sheet 30 in each magnet accommodating hole 24. As the magnetic powder used for the permanent magnet 23 in this embodiment, for example, a samarium iron nitrogen (SmFeN) magnet is used, but other rare earth magnets and the like may also be used.

[0022] As shown in FIG. 2, the permanent magnet 23 has a substantially V-shaped folded shape that protrudes toward the radial inside when viewed in the axial direction, that is, a shape in which the radially inner ends of a pair of straight portions 23a are connected to each other by a bent portion 23b. The radially outer end 23c of the straight portion 23a is located near the outer circumferential surface 22a of the rotor core 22. The permanent magnet 23 is set so that the thickness Wm of the pair of straight portions 23a is constant, and the thickness Wm1 of the bent portion 23b is gradually narrower than the thickness Wm of the straight portions 23a. The permanent magnet 23 is formed directly in the magnet accommodating hole 24, and therefore has a shape corresponding to the magnet accommodating hole 24. The permanent magnet 23 has an axisymmetric shape with respect to its own circumferential center line Ls that passes through the axial center O1 of the rotor 20, and is close to the magnetic pole boundary line Ld that passes through the axial center O1 of the rotor 20 between adjacent permanent magnets 23. The angle between adjacent magnetic pole boundary lines Ld, that is, the magnetic pole opening angle θm of the rotor magnetic pole portion 26 including this permanent magnet 23, is 180° in electrical angle.

[0023] Here, the magnetic pole pitch Lp is the intersection between the extension of the inner surface of each straight portion 23a of the V-shaped permanent magnet 23 and the outer peripheral surface 22a of the rotor core 22, and the embedding depth Lm is the distance from the outer peripheral surface 22a of the rotor core 22 to the inner surface of the bent portion 23b on the circumferential center line Ls of the permanent magnet 23. The permanent magnet 23 of this embodiment is set to have a deep folded shape near the center of the rotor core 22 such that the embedding depth Lm is larger than the magnetic pole pitch Lp. In other words, the magnet surface 23d of the permanent magnet 23 of this embodiment formed by the inner surfaces of each straight portion 23a and the bent portion 23b is set to be larger than the magnet surface of a well-known surface magnet type magnet (not shown). Note that this folded shape of the permanent magnet 23 is one example, and it can be appropriately changed to one with a shallow embedding depth Lm or a folded shape of an approximately U shape with a large bent portion 23b.

[0024] 3, the permanent magnet 23 is provided over the entire axial length of the rotor core 22, and a portion of the permanent magnet 23 protrudes from both axial end faces 22c of the rotor core 22. The permanent magnet 23 has an embedded magnet portion 23m located in the magnet accommodating hole 24 and a protruding portion 23x protruding from each of the axial end faces 22c of the rotor core 22. The protruding portion 23x can be easily formed, for example, by simply providing a recess for forming the protruding portion 23x in a molding die (not shown) for closing the magnet accommodating hole 24 that opens into the axial end face 22c of the rotor core 22. The protruding portion 23x is provided integrally and continuously with the embedded magnet portion 23m of the permanent magnet 23 located in the magnet accommodating hole 24 of the rotor core 22.

[0025] The permanent magnets 23 provided in a substantially embedded manner in the magnet accommodating holes 24 of the rotor core 22 are magnetized from the outside of the rotor core 22 using a magnetizing device (not shown) so that the magnets function as intended magnets after the magnetic material has solidified. In this case, each permanent magnet 23 is magnetized in its own thickness direction. As shown in Fig. 1, eight permanent magnets 23 are provided in the circumferential direction of the rotor core 22 in this embodiment, and are magnetized so that the polarities are alternately different in the circumferential direction.

[0026] A portion of the rotor core 22 located inside the V-shaped folded shape of the permanent magnet 23 and radially outside the permanent magnet 23 functions as an outer core portion 25 for obtaining reluctance torque by facing the stator 10. The outer core portion 25 has a substantially triangular shape with one apex facing toward the center of the rotor 20 when viewed in the axial direction. In this embodiment, the rotor 20 includes the permanent magnet 23 and the outer core portion 25 surrounded by the inside of the V-shape of the permanent magnet 23, and is configured as an eight-pole rotor magnetic pole portion 26. The rotor magnetic pole portions 26 function as N poles and S poles alternately in the circumferential direction as shown in FIG. 1. In the rotor 20 having such rotor magnetic pole portions 26, magnet torque and reluctance torque can be suitably obtained.

[0027] The operation of the rotor 20 of the rotating electric machine M of this embodiment will be described. The rotor core 22 constituting the rotor 20 of this embodiment is formed by stacking a plurality of core sheets 30 in which the first magnet through holes 31 having the connecting portions 31c shown in FIG. 4 and the second magnet through holes 32 without connecting portions are alternately arranged in the circumferential direction. In this case, only one type of core sheet 30 is prepared. Then, as shown in FIG. 3, a predetermined number of core sheets 30 are stacked so that the core sheets 30 arranged in the first position and the second position rotated by 45 degrees are alternately arranged, thereby forming the rotor core 22. Thereafter, the permanent magnets 23 are directly formed in the individual magnet accommodating holes 24α, 24β of the first and second modes, which are substantially similar in configuration except that the order of the first and second magnet through holes 31, 32 is different, and then the permanent magnets 23 are magnetized to form the rotor 20.

[0028] 2 and 3, in the rotor core 22, the outer core portion 25 located radially outward from the permanent magnets 23 is supported by the common portion 22x of the rotor core 22 at three points: two connecting portions 22d located outside the radially outer end portion 24c of the magnet accommodating hole 24, and connecting portions 31c located at the radially inner bent portion 24b and provided on every other core sheet 30. In other words, the outer core portion 25 of the rotor core 22 in this embodiment is supported at three points by newly adding the connecting portion 31c in addition to the two connecting portions 22d that are necessarily provided due to the configuration of the magnet accommodating hole 24, and therefore the centrifugal force strength of the outer core portion 25 is improved.

[0029] FIG. 5 shows the results of comparison between this embodiment (this embodiment in the figure) and Comparative Example 1 and Comparative Example 2 (Comparative Example 1 and Comparative Example 2 in the figure) used to evaluate the centrifugal force strength of the outer core portion 25. In Comparative Example 1, the permanent magnet 23 has a shallow folded shape with an embedment depth Lm (see FIG. 2) of about half the radius of the rotor core 22. In Comparative Example 2, the permanent magnet 23 has a deep folded shape like this embodiment in which the permanent magnet 23 approaches the center of the rotor core 22, but has a magnet accommodating hole 24 without a connecting portion 31c at the bent portion 24b. In Comparative Example 2, the permanent magnet 23 does not have a protruding portion 23x (see FIG. 3), and the magnet accommodating hole 24 does not have a protruding portion 22e (see FIG. 2). In addition, Comparative Example 2 is compared with this embodiment when the stress applied to the two connecting portions 22d supporting the outer core portion 25 in Comparative Example 1 is set to "1". In Comparative Example 2, the permanent magnet 23 has a deeper folded shape than in Comparative Example 1, and the magnet surface 23d of the permanent magnet 23 and the outer core portion 25 itself are larger, so higher torque can be expected, but the weight of the outer core portion 25 is also larger, and the stress on the connecting portion 22d is larger than in "1." In other words, this means that the centrifugal force strength of the outer core portion 25 is reduced.

[0030] In contrast, in this embodiment, outer core portion 25 is supported at three points by adding connecting portion 31c in addition to two connecting portions 22d, so that the stress on connecting portion 22d is sufficiently smaller than "1." In other words, this shows that the centrifugal force strength of outer core portion 25 is improved.

[0031] Here, even if two types of core sheets 30 are prepared, a core sheet 30 provided only with a through hole 31 for a first magnet having a connecting portion 31c and a core sheet 30 provided only with a through hole 32 for a second magnet without a connecting portion, and the different types of core sheets 30 are alternately stacked, the centrifugal force strength of the outer core portion 25 can be improved in the same manner as above. However, it is necessary to prepare two types of core sheets 30, which may be cumbersome in terms of manufacturing and management.

[0032] In contrast, in this embodiment, the first magnet through hole 31 having the connecting portion 31c and the second magnet through hole 32 without the connecting portion are mixed in one core sheet 30, and the core sheets 30 are laminated so that the first magnet through hole 31 and the second magnet through hole 32 are mixed in one magnet accommodating hole 24. In this embodiment, the first and second magnet through holes 31, 32 are mixed alternately in each core sheet 30. In other words, this embodiment can be realized by a simple measure of just preparing one type of core sheet 30.

[0033] 6 shows the results of comparing the torque / magnet volume ratio between this embodiment (this embodiment in the figure) and comparative examples 1 and 2 (comparison 1 and comparison 2 in the figure). As described above, in comparative example 2, the permanent magnet 23 has a deeper folded shape than in comparative example 1, and therefore the magnet surface 23d of the permanent magnet 23 and the outer core portion 25 itself are larger, resulting in a high torque, and the torque / magnet volume ratio is greater than "1."

[0034] On the other hand, in this embodiment, the outer core portion 25 is supported at three points by adding a connecting portion 31c in addition to the two connecting portions 22d. The connecting portions 22d and 31c are also portions where magnetic flux leakage of the permanent magnet 23 occurs, and the addition of the connecting portion 31c is a concern as it may reduce the effective magnetic flux and reduce the torque / magnet volume ratio. In this embodiment, as a countermeasure, a protruding portion 23x is provided in which a part of the permanent magnet 23 protrudes from the axial end face 22c of the rotor core 22. By causing the magnetic flux leakage at the axial end face 22c of the rotor core 22 at the protruding portion 23x, the magnetic flux leakage at the embedded magnet portion 23m of the permanent magnet 23, which is essential, is reduced, that is, the effective magnetic flux can be increased, and high torque can be achieved. Furthermore, by focusing on the fact that magnetic flux leakage at the bent portion 23b of the permanent magnet 23 is small, the volume of the permanent magnet 23 is minimized by setting the thickness of the bent portion 23b to Wm1, and the torque / magnet volume ratio can be improved. As a result, in this embodiment, although the increase in the number of connecting portions 31c increases magnetic flux leakage in these portions, it is possible to obtain a torque / magnet volume ratio equivalent to that of Comparative Example 2, which has no connecting portions.

[0035] However, even if the permanent magnet 23 is not provided with a protrusion 23x and even if the thickness of the curved portion 23b is not thinned, the decrease in the torque / magnet volume ratio is not very large and is greater than "1" (not shown). Therefore, in cases where an expensive magnetic material is used for the permanent magnet 23, it is sufficient to determine whether or not to form the protrusion 23x on the permanent magnet 23 and whether or not to adjust the thickness of the curved portion 23b, taking into account the magnet cost.

[0036] The effects of this embodiment will be described. (1) In one core sheet 30, a first magnet through hole 31 having a connecting portion 31c at a midpoint of the folded shape corresponding to the magnet accommodating hole 24 of the rotor core 22, which is a bent portion 24b in this embodiment, and a second magnet through hole 32 without a connecting portion are provided alternately in the circumferential direction. When stacking to form the rotor core 22, core sheets 30 of the same configuration are used, and the core sheets 30 are stacked alternately between a first position and a second position rotated by 45° for each sheet so that the first magnet through hole 31 and the second magnet through hole 32 are mixed in the configuration of one magnet accommodating hole 24. In other words, the outer core portion 25 of the rotor core 22 located radially outward from the permanent magnets 23 is supported by the common portion 22x of the rotor core 22 at three points, which are the two connecting portions 22d outside the radially outer end portion 24c of the rotor core 22, which are necessarily provided due to the configuration of the magnet accommodating hole 24 of the embedded magnet type rotor 20, and the connecting portion 31c of the first magnet through hole 31. This improves the centrifugal force strength of the outer core portion 25. Moreover, this can be achieved by simply preparing one type of core sheet 30.

[0037] (2) Since the core sheets 30 have the first magnet through holes 31 and the second magnet through holes 32 arranged alternately in the circumferential direction, the core sheets 30 can be simply stacked in such a manner that each core sheet 30 is arranged either in a first position or in a second position rotated from the first position by one magnet accommodating hole 24. Furthermore, by arranging each core sheet 30 in the first or second position, the connecting portions 31c of the first magnet through holes 31 are on every other core sheet 30 and do not overlap, so that magnetic flux leakage at the connecting portions 31c can be reduced as much as possible.

[0038] (3) The connecting portion 31c provided in the first magnet through hole 31 is located at the folded-back bent portion 31b of the first magnet through hole 31 itself, and is positioned in a balanced manner around the outer core portion 25 in terms of its positional relationship with the two connecting portions 22d, thereby contributing to stable support of the outer core portion 25.

[0039] (4) The width Wb of the connecting portion 31c provided in the first magnet through hole 31 is set to be equal to or smaller than the plate thickness t of the core sheet 30, so that magnetic flux leakage at the connecting portion 31c can be reduced as much as possible.

[0040] (5) The connecting portion 31c provided in the first magnet through hole 31 has its side edge 31d in a uniformly curved shape that narrows toward the center in the direction in which it extends, so that it is possible to minimize magnetic flux leakage at the connecting portion 31c while increasing rigidity by making the end portion wider. In addition, by making the side edge 31d in a curved shape, it is possible to reduce stress concentration on the connecting portion 31c.

[0041] (6) The rotor core 22 has a protruding portion 22e at one corner of the radial outer end 24c of the magnet accommodating hole 24 to make it narrower. This makes it possible to shorten the outer connecting portion 22d of the radial outer end 24c, thereby contributing to improving the centrifugal force strength of the outer core portion 25.

[0042] (7) Since the axial end of the permanent magnet 23 protrudes from the axial end face 22c of the rotor core 22 as the protrusion 23x, magnetic flux leakage at the axial end face 22c of the rotor core 22 occurs mainly at the protrusion 23x. In other words, since magnetic flux leakage from the embedded magnet portion 23m of the permanent magnet 23, which is the essential point, can be reduced, the effective magnetic flux can be increased, and higher torque can be achieved.

[0043] (8) The thickness Wm1 of the bent portion 23b of the permanent magnet 23 is smaller than the thickness Wm of the straight portion 24a. In other words, by focusing on the small amount of magnetic flux leakage at the bent portion 23b of the permanent magnet 23, the bent portion 23b is made thinner than the straight portion 24a to minimize the volume of the permanent magnet 23, thereby improving the torque / magnet volume ratio.

[0044] This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction. The configuration of the magnet accommodating hole 24 and the periphery of the magnet accommodating hole 24 may be changed as appropriate.

[0045] As shown in Fig. 7, for example, the protruding portion 22f protruding in a tapered shape at the radial outer end 24c of the magnet accommodating hole 24 may be provided at the outer corner of the V-shaped folded shape. That is, the protruding portion 22f may be provided at the corner on the opposite side to the protruding portion 22e described above. In Fig. 7, the protruding portion 22f may be provided only on the magnet accommodating hole 24β side of the second embodiment, and the hole shape of the radial outer end 24c of the magnet accommodating hole 24α side of the first embodiment may be a rectangle without the protruding portion 22f. That is, the protruding portion 22e or the protruding portion 22f may be provided on all of the magnet accommodating holes 24 that are present in the circumferential direction, or may be provided only on some of them.

[0046] Also, as shown in Figs. 8 and 9, for example, the hole width (corresponding to the thickness Wm2 of the permanent magnet 23) on the magnet accommodating hole 24β side of the second embodiment may be configured to be narrower. Also, as shown in Fig. 8, for example, the straight portion 24a of the magnet accommodating hole 24β of the second embodiment may be configured to be spaced apart from the magnetic pole boundary line Ld as it approaches the bent portion 24b. In this case, the straight portion 24a is inclined with respect to the magnetic pole boundary line Ld. Also, as shown in Fig. 9, for example, the straight portion 24a of the magnet accommodating hole 24β of the second embodiment may be configured to be spaced apart from the magnetic pole boundary line Ld uniformly from the radial outer end portion 24c to the bent portion 24b. In this case, the straight portion 24a is parallel to the magnetic pole boundary line Ld. These may be applied to the magnet accommodating hole 24α side of the first embodiment.

[0047] 10, for example, the protruding portion 23x of the permanent magnet 23 may be omitted. In this case, the end of the permanent magnet 23 is flush with the axial end face 22c of the rotor core 22. Also, as shown in FIG 10, for example, the hole width of the bent portion 24b of the magnet accommodating hole 24 (corresponding to the thickness Wm of the permanent magnet 23) may be set to the same width as the straight portion 24a.

[0048] Although the core sheets 30 are arranged so that each sheet alternates between the first position and the second position rotated by 45 degrees, multiple sheets may be arranged alternately between the first and second positions. In this case, the same number of sheets may be arranged alternately, or different numbers of sheets may be arranged alternately.

[0049] The through holes 31 for the first magnet and the through holes 32 for the second magnet are arranged alternately in the circumferential direction of the core sheet 30, i.e., the through holes 31, 32 for the first and second magnets are arranged every other one, but either the through holes 31, 32 for the first and second magnets may be arranged every third or more.

[0050] Although the first magnet through hole 31 has one connecting portion 31c, two or more may be provided. In this case, the support points of the outer core portion 25 are four or more in total, in addition to the two connecting portions 22d that are necessarily provided due to the configuration of the magnet accommodating hole 24 of the rotor core 22. Also, with regard to the arrangement position of the connecting portions such as the connecting portion 31c, the connecting portion 31c is provided at the bent portion 24b as an intermediate position of the folded back shape of the magnet accommodating hole 24, in this case the connecting portion 31c is provided at the bent portion 31b of the first magnet through hole 31, but it may be provided at a portion other than the bent portion 31b, for example the straight portion 31a in the above embodiment. Furthermore, with regard to the direction in which connecting parts such as connecting part 31c extend, in the above embodiment connecting part 31c has a shape extending in the hole width direction of the first magnet through hole 31, in this case a direction perpendicular to the inner peripheral edge portion of the first magnet through hole 31, and further a shape extending in the radial direction; however, this may be modified as appropriate, for example, to a shape extending in a diagonal direction relative to the hole width direction or a direction other than the radial direction.

[0051] Although the protruding portions 22e, 22f provided at the radially outer end 24c of the magnet accommodating hole 24 are formed to protrude in a tapered shape, the protruding shape may be changed as appropriate to a rectangular shape, a curved shape, etc. Also, as described above, the protruding portions 22e, 22f may be omitted, and the hole shape of the radially outer end 24c of the magnet accommodating hole 24 may be rectangular, as shown in Fig. 7, etc.

[0052] Although the permanent magnets 23 are formed by injection molding a magnetic material into the magnet accommodating holes 24 of the rotor core 22, the permanent magnets 23 may be manufactured in advance and then inserted and fixed into the magnet accommodating holes 24 of the rotor core 22.

[0053] The number of magnetic poles of the rotor 20, i.e., the number of permanent magnets 23 and magnet accommodating holes 24, may be changed as appropriate. Also, the number of magnetic poles of the stator 10 may be changed as appropriate. Other than the above, the configuration of the rotating electric machine M may be changed as appropriate.

[0054] In the above embodiment, an example of a configuration in which unevenness is provided on the inner surface of the magnet accommodating hole 24 is shown in Figs. As shown in FIG. 11, the inner surface of the magnet accommodating hole 24 in contact with the permanent magnet 23 includes an inner side surface 41 and an outer side surface 42. The inner side surface 41 is a side surface constituting the outer core portion 25, and is a surface that is in contact with the inside of the V-shaped folded shape of the permanent magnet 23. The outer side surface 42 is a side surface that faces the inner side surface 41 in the hole width direction. The hole width direction of the magnet accommodating hole 24 is a direction perpendicular to the extension direction of the magnet accommodating hole 24 when viewed in the axial direction. The extension direction of the magnet accommodating hole 24 is a direction along the approximately V-shaped folded shape when the magnet accommodating hole 24 is viewed from the axial direction. Each of the inner side surface 41 and the outer side surface 42 is a surface that follows the folded shape of the magnet accommodating hole 24 when viewed in the axial direction.

[0055] The inner side surface 41 has a first uneven portion 43. The outer side surface 42 has a second uneven portion 44. The first uneven portion 43 is provided on the inner side surface 41 at the bent portion 24b. The second uneven portion 44 is provided on the outer side surface 42 at the bent portion 24b. A third uneven portion 45 is provided on the inner surface of the magnet accommodating hole 24 at a portion corresponding to the radially outer end portion 24c of the straight portion 24a. In this example, the inner surface of the magnet accommodating hole 24 has a non-uneven portion 46 which is a portion where the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 are not formed. The first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 are formed partially in the extension direction of the magnet accommodating hole 24, and the non-uneven portion 46 is formed at other points in the extension direction of the magnet accommodating hole 24.

[0056] The individual core sheets 30 constituting the rotor core 22 have the same configuration as shown in Fig. 14(a). This makes it possible to manage each core sheet 30 as the same part. The core sheet 30 shown in Fig. 14(b) appears to have a different shape from the core sheet 30 shown in Fig. 14(a), but in fact it is arranged at a second position rotated 45°, which is the amount of one magnet accommodating hole 24, in other words, one magnetic pole, from the first position shown in Fig. 14(a).

[0057] In the process of stacking the core sheets 30 to form the rotor core 22, in this example, the core sheets 30 are stacked one by one so that the core sheets 30 arranged in the first position shown in Fig. 14(a) and the core sheets 30 arranged in the second position rotated by 45° and shown in Fig. 14(b) are alternately stacked. As a result, the first magnet through holes 31 and the second magnet through holes 32 overlap alternately in the axial direction. Then, each magnet accommodating hole 24 is formed by the first magnet through holes 31 and the second magnet through holes 32 that overlap in the axial direction.

[0058] On the inner surface of the magnet accommodating hole 24, the first uneven portion 43, the second uneven portion 44 and the third uneven portion 45 are each formed by the difference in position of the peripheral portions of the first magnet through hole 31 and the second magnet through hole 32.

[0059] 11 and 12, the hole width of the bent portion 31b of the first magnet through hole 31 is narrower than the hole width of the bent portion 32b of the second magnet through hole 32. The radial center positions of the bent portions 31b, 32b are set to the same position. The first uneven portion 43 and the second uneven portion 44 are formed by the difference in hole width between the bent portions 31b, 32b.

[0060] 12, the first uneven portion 43 has a plurality of recesses 43a in the axial direction. The permanent magnet 23 has an engagement portion 51 that fits into each recess 43a of the first uneven portion 43. Each engagement portion 51 is adapted to be hooked onto each recess 43a in the axial direction.

[0061] The second uneven portion 44 has a plurality of recesses 44a in the axial direction. The permanent magnet 23 has an engagement portion 52 that fits into each recess 44a of the second uneven portion 44. Each engagement portion 52 is adapted to be hooked onto each recess 44a in the axial direction. In this example, the depth D1 of the recesses 43a of the first uneven portion 43 is set to a depth equal to the depth D2 of the recesses 44a of the second uneven portion 44 provided on the outer side surface 42. In addition, each of the depth D1 of the recesses 43a and the depth D2 of the recesses 44a gradually becomes shallower, for example, as it approaches the straight portion 24a.

[0062] The third uneven portion 45 is formed by a difference in shape at the radially outer end of each of the straight portion 31a, 32a of the first magnet through hole 31 and the second magnet through hole 32. As shown in Fig. 14(a), a protruding portion 31e that protrudes inward in the hole width direction from the straight portion 31a is formed at the radially outer end of the straight portion 31a of the first magnet through hole 31. The protruding portion 31e is formed at an inner corner portion of a V-shaped turn-back shape at the radially outer end of the straight portion 31a. The protruding portion 31e is also formed by tapering the inner corner portion.

[0063] As shown in FIG. 13, the third uneven portion 45 is formed by overlapping a straight portion 31a having a protruding portion 31e and a straight portion 32a having no protruding portion in the axial direction. The third uneven portion 45 has a plurality of recesses 45a in the axial direction. The recesses 45a are formed of straight portions 32a having no protruding portion. The protruding portions of the third uneven portion 45 are formed of the protruding portions 31e. The permanent magnet 23 has an engagement portion 53 that enters each recess 45a of the third uneven portion 45. Each engagement portion 53 is adapted to be hooked onto each recess 45a in the axial direction. The protruding portion 31e may be formed in the second magnet through hole 32 instead of the first magnet through hole 31.

[0064] 11, the non-convexoconcave portion 46 is a portion on the inner surface of the magnet accommodating hole 24 where the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are not formed. That is, when the magnet accommodating hole 24 is viewed from the axial direction, in the non-convexoconcave portion 46, the positions of the peripheral portions of the first magnet through hole 31 and the second magnet through hole 32 that overlap in the axial direction are aligned.

[0065] 11, rotor core 22 is provided with a connecting portion 61 that connects opposing inner circumferential edges in the hole width direction at a midpoint of the folded shape corresponding to magnet accommodating hole 24. Connecting portion 61 is provided at bent portion 24b of magnet accommodating hole 24, for example.

[0066] In this example, the connecting portion 61 is formed only in the first magnet through hole 31 among the first magnet through hole 31 and the second magnet through hole 32. The connecting portion 61 is formed in the bent portion 31b of each first magnet through hole 31. The connecting portion 61 extends in the hole width direction of the bent portion 31b to connect the inner peripheral edge portions facing each other in the same direction. In the connecting portion 61 of each first magnet through hole 31, the width in the direction perpendicular to the extending direction of the connecting portion 61 is set to be, for example, equal to each other. In addition, when each core sheet 30 is stacked as the rotor core 22, each connecting portion 61 in one magnet accommodating hole 24 is arranged on a straight line along the axial direction.

[0067] In this example, the hole width of the bent portion 31b of the first magnet through hole 31 is smaller than the hole width of the bent portion 32b of the second magnet through hole 32. Therefore, by providing the connecting portion 61 at the bent portion 31b of the first magnet through hole 31, the length of the connecting portion 61 in the hole width direction can be made shorter than when a connecting portion is provided at the bent portion 32b of the second magnet through hole 32.

[0068] Also, in this example, no connecting portion is formed in the second magnet through hole 32. Therefore, in the bent portion 24b of the magnet accommodating hole 24, there are portions where there is no connecting portion on every other core sheet 30. And, the magnetic material constituting the permanent magnet 23 fills in the portions where there is no connecting portion. The connecting portion 61 is provided between the first uneven portion 43 and the second uneven portion 44. In other words, the connecting portion 61 connects the first uneven portion 43 and the second uneven portion 44.

[0069] 11 to 13, the outer core portion 25 is supported at three points, including the two connecting portions 22d that are necessarily provided in the configuration of the magnet accommodating hole 24, and a new connecting portion 61 located at the bent portion 24b. This improves the centrifugal force strength of the outer core portion 25. In addition, the three support points consisting of the two connecting portions 22d and the connecting portion 61 are arranged in a well-balanced manner around the outer core portion 25. This contributes to stable support of the outer core portion 25.

[0070] In the rotor 20 using the permanent magnet 23 having a folded shape that is convex toward the inside in the radial direction, the volume of the outer core portion 25 located on the radial outside of the permanent magnet 23 becomes large. In addition, if the radially outer end of the permanent magnet 23 is extended to the vicinity of the outer circumferential surface 22a of the rotor core 22 in order to increase the torque, the thickness of the connecting portion 22d becomes thin, and the strength of the connecting portion 22d tends to be reduced. For this reason, when an axial vibration force is applied to the rotor 20 due to an external factor, for example, a force is generated that tries to vibrate the outer core portion 25 in the axial direction with the connecting portion 22d as a fulcrum. This applies a load to the connecting portion 61, and if no countermeasure is taken, the connecting portion 61 may be deformed.

[0071] In this regard, in the configuration shown in Figs. 11 to 13, the permanent magnet 23 made of a bonded magnet filled in the magnet accommodating hole 24 engages with the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 of the magnet accommodating hole 24 in a so-called anchor effect. That is, the outer core portion 25 engages with the V-shaped inner surface of the permanent magnet 23 in the axial direction by the first uneven portion 43 and the third uneven portion 45. Also, the V-shaped outer surface of the permanent magnet 23 engages with the portion of the rotor core 22 other than the outer core portion 25 in the axial direction by the second uneven portion 44. This makes it possible to suppress the outer core portion 25 from vibrating in the axial direction with the connecting portion 22d as a fulcrum, even if an axial vibration force is applied to the rotor 20 due to an external factor, for example. As a result, the load on the connecting portion 61 is reduced. In this way, deformation of the connecting portion 61 caused by axial vibration of the outer core portion 25 can be suppressed by the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45. That is, the configuration of this example can contribute to improving both the centrifugal strength and the axial strength of the outer core portion 25.

[0072] In the above example, the inner surface of the magnet accommodating hole 24 is provided with a non-uneven portion 46 which is a portion where the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 are not formed. This makes it possible to suppress axial leakage magnetic flux that occurs due to the unevenness of the boundary between the magnet accommodating hole 24 and the permanent magnet 23, compared to a configuration in which the entire inner surface of the magnet accommodating hole 24 has uneven portions.

[0073] In the above example, the inner surface of the magnet accommodating hole 24 includes an inner side surface 41 that forms the outer core portion 25, and an outer side surface 42 that faces the inner side surface 41. A first uneven portion 43 and a third uneven portion 45 are provided on the inner side surface 41. A second uneven portion 44 is provided on the outer side surface 42. With this configuration, since the inner side surface 41 and the outer side surface 42 of the magnet accommodating hole 24 each have unevenness, the unevenness can more effectively suppress vibration of the outer core portion 25. Furthermore, since the non-uneven portion 46 is provided on each of the inner side surface 41 and the outer side surface 42 of the magnet accommodating hole 24, the effect of suppressing leakage magnetic flux by providing the non-uneven portion 46 can be more suitably obtained.

[0074] In the above example, the first uneven portion 43 and the second uneven portion 44 are provided within the range of a reference circle C1 having a diameter that is half the outer diameter of the rotor core 22. The reference circle C1 is a circle centered on the axial center O1 of the rotor 20. The range indicated by the reference circle C1 is a range toward the radial inner side of the rotor core 22, that is, a range that is unlikely to contribute to output. For this reason, by providing the first uneven portion 43 within the range of the reference circle C1, it is possible to minimize the reduction in output caused by providing the first uneven portion 43.

[0075] In the above example, the first uneven portion 43 and the second uneven portion 44 are provided on the folded-back bent portion 24b of the magnet accommodating hole 24. With this configuration, the radially inner end portion of the outer core portion 25 located away from the connecting portion 22d can be axially engaged with the permanent magnet 23 by the first uneven portion 43 and the second uneven portion 44. Therefore, the axial vibration of the outer core portion 25 with the connecting portion 22d as a fulcrum can be effectively suppressed by the first uneven portion 43 and the second uneven portion 44.

[0076] In the above example, the third uneven portion 45 is provided at the radially outer end 24c of the magnet accommodating hole 24. This configuration makes it possible to suppress vibration near the radially outer end of the outer core portion 25. The protruding portion of the third uneven portion 45 is formed by a protruding portion 31e that protrudes inward in the hole width direction of the magnet accommodating hole 24. The protruding portion 31e is formed in the first magnet through hole 31. This makes it possible to shorten the circumferential length of the connecting portion 22d corresponding to the first magnet through hole 31. As a result, this can contribute to improving the moldability of the core sheet 30.

[0077] Moreover, the protruding portion 31e is formed at the inner corner of the V-shaped turn-back shape at the radially outer end of the straight portion 31a. This makes it possible to configure the third uneven portion 45 by the protruding portion 31e while minimizing the magnetic flux reduction of the permanent magnet 23. Furthermore, by providing the protruding portion 31e, it is possible to reduce the volume of the permanent magnet 23 while minimizing the magnetic flux reduction, thereby improving the output torque per unit volume of the permanent magnet 23.

[0078] In the above example, the multiple core sheets 30 have the same configuration. In each core sheet 30, the first magnet through hole 31 and the second magnet through hole 32 having different shapes are provided in a mixed manner. The first magnet through hole 31 and the second magnet through hole 32 are mixed in the configuration of one magnet accommodating hole 24. With this configuration, the first magnet through hole 31 and the second magnet through hole 32 overlapping in the axial direction can form the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 in the magnet accommodating hole 24 while facilitating parts management by making each core sheet 30 have the same configuration.

[0079] In addition, in the above example, it is possible to minimize magnetic imbalance that may occur by forming a through hole 31 for a first magnet and a through hole 32 for a second magnet, which have different shapes, in a single core sheet 30.

[0080] In the example shown in Figure 11, the first uneven portion 43 and the second uneven portion 44 are formed by differing the hole widths of the bent portions 31b, 32b of the first magnet through hole 31 and the second magnet through hole 32, but this is not particularly limited and may be changed as appropriate.

[0081] 15 and 16, the radial widths of the bent portions 31b, 32b of the first magnet through hole 31 and the second magnet through hole 32 may be made equal, and the first uneven portion 43 and the second uneven portion 44 may be formed by the difference in the radial positions of the bent portions 31b, 32b. In the configuration shown in the figures, the first uneven portion 43 and the second uneven portion 44 are formed by the difference in the radial positions of the bent portion 31b of the first magnet through hole 31 and the bent portion 32b of the second magnet through hole 32. The bent portion 31b of the first magnet through hole 31 is located radially inward of the bent portion 32b of the second magnet through hole 32.

[0082] With such a configuration, it is possible to obtain substantially the same effect as the configuration shown in Fig. 11. Moreover, with the configuration shown in Fig. 15, it is possible to form the first uneven portion 43 and the second uneven portion 44 on the inner surface of the magnet accommodating hole 24 while ensuring that the magnetic properties of the permanent magnets 23 formed in each magnet accommodating hole 24 are not different from each other. It is also possible to combine a configuration in which the positions of the bent portions 31b, 32b are made different and a configuration in which the hole widths of the bent portions 31b, 32b are made different.

[0083] In each of the above examples, the core sheets 30 are arranged so that each sheet alternates between the first position and the second position rotated by 45°, but the core sheets 30 may be arranged alternately between the first and second positions in units of multiple sheets. In this case, the same number of sheets may be arranged alternately, or different numbers of sheets may be arranged alternately. FIG. 17 shows, as an example, a configuration in which every two core sheets 30 are stacked so that the first position and the second position rotated by 45° are arranged alternately. With such a configuration, it is possible to obtain substantially the same effect as each of the above examples.

[0084] In each of the above examples, the position where the uneven portion is formed on the inner surface of the magnet accommodating hole 24 is not limited to the above examples and can be changed as appropriate. For example, the uneven portion may be formed on the inner surface of the magnet accommodating hole 24 in the middle of the straight portion 24a when viewed in the axial direction.

[0085] In addition, in the magnet accommodating hole 24 of each of the above examples, for example, any one of the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 may be omitted. In each of the above examples, the connecting portion 61 is provided between the first uneven portion 43 and the second uneven portion 44, but other than this, for example, the connecting portion 61 may be provided in the non-uneven portion 46.

[0086] In the above example, the first uneven portion 43, the second uneven portion 44, and the third uneven portion 45 are formed partially in the extension direction of the magnet accommodating hole 24, and the non-uneven portion 46 is formed at other locations in the extension direction of the magnet accommodating hole 24, but this is not particularly limited. For example, an uneven portion may be formed on the inner surface of the magnet accommodating hole 24 in a part of the axial direction, and a non-uneven portion may be formed at locations in the axial direction other than the uneven portion.

[0087] 18, the uneven portion 71 may be formed on the entire inner surface of each magnet accommodating hole 24. In the configuration shown in the figure, the first magnet through hole 31 is slightly smaller than the second magnet through hole 32. The first magnet through hole 31 and the second magnet through hole 32, which have different shapes, overlap in the axial direction, so that the uneven portion 71 is formed on the entire inner surface of the magnet accommodating hole 24. With this configuration, it is possible to ensure a large area for the uneven portion 71 on the inner surface of the magnet accommodating hole 24. As a result, it is possible to more suitably suppress the axial vibration of the outer core portion 25.

[0088] In each of the above examples, the first magnet through hole 31 has one connecting portion 61, but two or more may be provided. In this case, the outer core portion 25 has a total of four or more support points in addition to the two connecting portions 22d that are necessarily provided due to the configuration of the magnet accommodating hole 24.

[0089] In addition, in each of the above examples, the connecting portion 61 is provided at the bent portion 24b of the magnet accommodating hole 24, but the connecting portion 61 may be provided at a portion other than the bent portion 24b, such as the straight portion 24a. Furthermore, in each of the above examples, the direction in which the connecting portion 61 extends is the hole width direction of the bent portion 24b of the magnet accommodating hole 24, and the radial direction of the rotor 20, but the direction may be changed as appropriate, for example, to a direction oblique to the hole width direction or a direction extending other than radially.

[0090] In the above embodiment and each of the above modified examples, the number of the first magnet through holes 31 and the second magnet through holes 32 in one core sheet 30 is the same, but this is not particularly limited. That is, the number of the first magnet through holes 31 in one core sheet 30 may be more or less than the number of the second magnet through holes 32. Regardless of the number of the first magnet through holes 31 and the second magnet through holes 32, the shapes of the first magnet through holes 31 and the second magnet through holes 32 are configured to be point symmetrical with respect to the axial center O1, thereby making it possible to suppress magnetic imbalance in the circumferential direction.

[0091] For example, in the core sheet 30 shown in FIG. 19, there are two first magnet through holes 31 and four second magnet through holes 32. The two first magnet through holes 31 are arranged at 180° opposing positions. This makes it possible to suppress magnetic imbalance in the circumferential direction. In the example shown in FIG. 19, the hole width of the bent portion 31b of the first magnet through hole 31 is narrower than the hole width of the bent portion 32b of the second magnet through hole 32. That is, the thickness of the bent portion 23b of the permanent magnet 23 is thinner in the first magnet through hole 31 than in the second magnet through hole 32. Therefore, by configuring the number of the first magnet through holes 31 to be less than the number of the second magnet through holes 32, it is possible to suppress the decrease in output torque.

[0092] In the above embodiment and each of the above modified examples, in the process of stacking the core sheets 30, each core sheet 30 is rotated by 45°, which is one magnetic pole, but the rotation angle during stacking is not limited to 45°, which is one magnetic pole, and may be an angle other than 45°, such as two or three magnetic poles.

[0093] The technical ideas that can be understood from the above-described embodiment and modified examples will be described. (i) The inner surface of the magnet accommodating hole is provided with uneven portions (43, 44, 45) formed by the difference in the position of the peripheral portions of the magnet through holes which overlap in the axial direction, and a non-uneven portion (46) which is a portion where the uneven portions are not formed.

[0094] According to this configuration, a non-convex portion is provided on the inner surface of the magnet accommodating hole, so that axial leakage magnetic flux generated by the uneven boundary between the magnet accommodating hole and the permanent magnet can be suppressed compared to a configuration in which the entire inner surface of the magnet accommodating hole has uneven portions.

[0095] (b) the rotor core has an outer core portion (25) that is a portion radially outward of the permanent magnets, the inner surface of the magnet accommodating hole includes an inner side surface (41) forming the outer core portion and an outer side surface (42) facing the inner side surface, The uneven portion is provided on each of the inner side surface and the outer side surface, The non-convex portion is provided on each of the inner side surface and the outer side surface.

[0096] According to this configuration, since the inner side surface and the outer side surface of the magnet accommodating hole each have a concave-convex portion, the vibration of the outer core portion can be more effectively suppressed by the concave-convex portion. Also, the inner side surface and the outer side surface of the magnet accommodating hole each have a non-convex portion. Therefore, it is possible to more preferably obtain the effect of suppressing leakage magnetic flux by providing the non-convex portion.

[0097] (c) The uneven portion is provided radially inwardly of half the outer diameter of the rotor core. According to this configuration, the range radially inward of half the outer diameter of the rotor core is a range that is unlikely to contribute to output, so by providing the uneven portion radially inward of half the outer diameter of the rotor core, it is possible to minimize the reduction in output caused by providing the uneven portion.

[0098] (iv) The uneven portion is provided on a bent portion (24b) of the magnet accommodating hole. According to this configuration, the radially inner end of the outer core portion can be axially engaged with the permanent magnet by the uneven portion provided in the bent portion, and therefore, the axial vibration of the outer core portion can be effectively suppressed by the uneven portion.

[0099] (e) The uneven portion is provided on the radially outer end (24c) of the magnet accommodating hole. With this configuration, vibrations can be suppressed in the vicinity of the radially outer end portion of the outer core portion. (f) The convex portion of the uneven portion provided at the radially outer end of the magnet accommodating hole is configured by a protruding portion (31e) that protrudes inward in the hole width direction of the magnet accommodating hole.

[0100] According to this configuration, by providing the protruding portion, the circumferential length of the connecting portion formed near the radially outer end of the magnet accommodating hole can be partially shortened, which contributes to improving the moldability of the core sheet.

[0101] (g) The protruding portion is formed at an inner corner portion of a folded-back shape of the magnet accommodating hole at a radially outer end portion of the magnet accommodating hole. With this configuration, it is possible to form the uneven portion by the protruding portion while minimizing the decrease in magnetic flux of the permanent magnet. Also, by providing the protruding portion, it is possible to reduce the volume of the permanent magnet while minimizing the decrease in magnetic flux, thereby improving the output torque per unit volume of the permanent magnet.

[0102] (h) In the connecting portions of the first magnet through holes formed in one of the core sheets, the widths in a direction perpendicular to the extending direction of the connecting portions are set to be equal to each other.

[0103] According to this configuration, when the core sheets are stacked to form a rotor core, the connecting parts in one magnet accommodating hole are arranged in a straight line along the axial direction. Therefore, when an axial excitation force is applied to the outer core part, a load is applied to each connecting part in one magnet accommodating hole approximately evenly. Therefore, it is possible to effectively suppress deformation of the connecting parts. [Explanation of symbols]

[0104] M rotating electric machine, 10 stator, 20 rotor, 22 rotor core, 22c axial end surface, 22e, 22f protruding portion, 23 permanent magnet, 23a straight portion (other portion), 23b bent portion, 23x protruding portion, 24 magnet accommodating hole, 24c radial outer end portion, 30 core sheet, 31 first magnet through hole, 31b bent portion, 31c, 61 connecting portion, 31d side edge portion, 32 second magnet through hole, t plate thickness, Wb width, Wm, Wm1 thickness, 43 first uneven portion (uneven portion), 43a recess, 44 second uneven portion (uneven portion), 44a recess, 45 third uneven portion (uneven portion), 45a recess, 51 to 53 engaging portion, 71 uneven portion.

Claims

1. A rotor (20) comprising a rotor core (22) formed by laminating a plurality of core sheets (30) and having a plurality of magnet accommodating holes (24) each having a convex folded shape on the radially inward side, and a permanent magnet (23) provided in an embedded manner in the magnet accommodating hole of the rotor core, The core sheet is provided with a mixture of a first magnet through hole (31) having a connecting portion (31c, 61) connecting inner peripheral edge portions facing each other in the hole width direction at a midpoint of the folded shape corresponding to the magnet accommodating hole, and a second magnet through hole (32) without the connecting portion (31c, 61), and The rotor core is constructed by stacking the core sheets having the same configuration such that the first magnet through hole and the second magnet through hole are mixed in the configuration of one of the magnet accommodating holes of the rotor core, The permanent magnet is a bonded magnet, A rotor, wherein a connecting portion provided in the first magnet through hole is configured so that its width (Wb) is set smaller than the plate thickness (t) of the core sheet.

2. The rotor according to claim 1 , wherein the core sheet is configured such that the first magnet through holes and the second magnet through holes are alternately arranged in a circumferential direction.

3. 3. The rotor core according to claim 2, wherein the core sheets are arranged in a predetermined number at either a first position or a second position rotated by one magnet accommodating hole from the first position.

4. The rotor according to claim 3 , wherein the rotor core is configured such that each of the core sheets is disposed in a first or second position.

5. 5. The rotor according to claim 1, wherein the connecting portion provided in the first magnet through hole is positioned at a folded-back bent portion (31b) of the first magnet through hole itself.

6. A rotor as described in any one of claims 1 to 5, wherein the connecting portion provided in the first magnet through hole is configured so that its side edge portion (31d) has a uniform curved shape such that it becomes narrower toward the central portion in the direction in which the connecting portion itself extends.

7. The rotor core is configured so as to have a protruding portion (22e, 22f) protruding from one corner to narrow a radially outer end (24c) of the magnet accommodating hole.

8. The rotor according to claim 1 , wherein the permanent magnet is provided with a protruding portion (23x) at least a part of which protrudes from an axial end face (22c) of the rotor core.

9. 9. The rotor according to claim 1, wherein the permanent magnet is configured such that a thickness (Wm1) of the folded-back curved portion (23b) is smaller than a thickness (Wm) of the other portion (23a).

10. An inner surface of the magnet accommodating hole is provided with an uneven portion (43, 44, 45, 71) formed by a difference in position of a peripheral portion of the first magnet through hole and the second magnet through hole which overlap in the axial direction, 10. The rotor according to claim 1, wherein the permanent magnet has an engagement portion (51, 52, 53) that fits into a recess (43a, 44a, 45a) of the uneven portion.

11. A rotor as described in any one of claims 1 to 10, wherein in each of the plurality of core sheets, two radially outer connecting portions (22d) are located radially outside each of the first magnet through holes and the second magnet through holes.

12. A rotor (20) including a rotor core (22) formed by laminating a plurality of core sheets (30) and having a plurality of magnet accommodating holes (24) each having a convex folded shape on the radially inward side, and a permanent magnet (23) provided in an embedded manner in the magnet accommodating hole of the rotor core; A stator (10) that applies a rotating magnetic field to the rotor; A rotating electric machine (M) comprising: The core sheet is provided with a mixture of a first magnet through hole (31) having a connecting portion (31c, 61) connecting inner peripheral edge portions facing each other in the hole width direction at a midpoint of the folded shape corresponding to the magnet accommodating hole, and a second magnet through hole (32) without the connecting portion (31c, 61), and The rotor core is constructed by stacking the core sheets having the same configuration such that the first magnet through hole and the second magnet through hole are mixed in the configuration of one of the magnet accommodating holes of the rotor core, The permanent magnet is a bonded magnet, A rotating electric machine, wherein a connecting portion provided in the first magnet through hole has a width (Wb) set smaller than a plate thickness (t) of the core sheet.

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