Rotating electric machine

Abstract

The invention provides a rotating electric machine. A rotor of a rotating electrical machine includes an inner center permanent magnet housed in an inner center housing hole of a rotor core, a pair of inner inclined permanent magnets housed in a pair of inner inclined housing holes on both sides of the inner center housing hole in the circumferential direction, and an outer center permanent magnet housed in an outer center housing hole on the outer side of the inner center housing hole in the radial direction. And a pair of outer inclined permanent magnets housed in the pair of outer inclined housing holes on both sides of the outer central housing hole in the circumferential direction. The rotor core has an inner rib provided between the inner central accommodation hole and the pair of inner inclined accommodation holes, and an outer rib provided between the outer central accommodation hole and the pair of outer inclined accommodation holes. The included angle between a first axis extending in the thickness direction from the center of the pair of inner inclined permanent magnets in the width direction and the center line of the magnetic pole is larger than the included angle between a second axis extending in the thickness direction from the center of the pair of outer inclined permanent magnets in the width direction and the center line of the magnetic pole.

Description

TECHNICAL FIELD

[0001] The present application relates to a rotary electric machine having a rotor in which permanent magnets are embedded. BACKGROUND

[0002] A rotary electric machine configured such that a plurality of magnets are respectively arranged on the inner and outer circumferential sides of a plurality of magnetic pole portions in the circumferential direction of a rotor is known. Such a rotary electric machine is described, for example, in Patent Literature 1. In the rotary electric machine described in Patent Literature 1, on both sides of the magnetic pole center of the plurality of magnetic pole portions in the circumferential direction of the rotor, a plurality of magnet filling portions each having a substantially V-shaped cross section are symmetrically arranged with respect to the magnetic pole center, and a magnet is arranged in each of the plurality of magnet filling portions.

[0003] When magnet filling portions are provided on both sides of the magnetic pole center of the rotor as in the rotary electric machine described in Patent Literature 1, in order to ensure that the rotor has sufficient strength, it is necessary to increase the length between a pair of magnet filling portions on both sides of the magnetic pole center of the rotor. However, when the length between the pair of magnet filling portions is increased, the magnetic flux leakage increases, resulting in a decrease in the maximum torque of the rotor.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2020-137139 (JP 2020-137139 A). SUMMARY

[0007] A rotating electric machine according to one aspect of the present application includes: a rotor that rotates around a rotational axis; and a stator that is disposed around an outer circumferential surface of the rotor and generates a rotating magnetic field that acts on the rotor. The rotor includes a rotor core provided with magnet housing holes that extend in an axial direction and permanent magnets housed in the magnet housing holes, and is composed of a plurality of magnetic pole portions in a circumferential direction. The magnet housing holes include a plurality of magnet housing holes that are symmetrically disposed with respect to a magnetic pole center line that extends radially from the rotational axis for each of the plurality of magnetic pole portions in the circumferential direction. The plurality of magnet housing holes include an inner central housing hole and an outer central housing hole that extend toward an inner radial side and an outer radial side, respectively, in a direction orthogonal to the magnetic pole center line, a pair of inner inclined housing holes that are disposed on both sides in the circumferential direction of the inner central housing hole and extend obliquely with respect to the magnetic pole center line in a manner that moves toward the outer radial side as it moves away from the magnetic pole center line, and a pair of outer inclined housing holes that are disposed on both sides in the circumferential direction of the outer central housing hole and extend obliquely with respect to the magnetic pole center line in a manner that moves toward the outer radial side as it moves away from the magnetic pole center line. The permanent magnets include a plurality of permanent magnets that have a width in a long side direction and a thickness in a short side direction and are housed in the plurality of magnet housing holes. The plurality of permanent magnets include an inner central permanent magnet housed in the inner central housing hole, a pair of inner inclined permanent magnets housed in the pair of inner inclined housing holes, an outer central permanent magnet housed in the outer central housing hole, and a pair of outer inclined permanent magnets housed in the pair of outer inclined housing holes. The rotor core has an inner rib disposed between the inner central housing hole and the pair of inner inclined housing holes, and an outer rib disposed between the outer central housing hole and the pair of outer inclined housing holes. A first reference line that extends from a center in a width direction of the pair of inner inclined permanent magnets toward a thickness direction has a larger angle with the magnetic pole center line than a second reference line that extends from a center in a width direction of the pair of outer inclined permanent magnets toward a thickness direction. BRIEF DESCRIPTION OF DRAWINGS

[0008] Objects, features, and advantages of the present application will be further clarified by the following description of embodiments with reference to the accompanying drawings.

[0009] Figure 1 is a cross-sectional view perpendicular to the axis that shows a main part structure of the rotating electric machine according to the embodiment of the present application;

[0010] Figure 2 is a view that shows a structure of a magnetic pole portion of the rotor; Figure 1 is a main part enlarged view of

[0011] Figure 3 is a view that shows a reference example of Figure 2

[0012] Figure 4 is a contour map that shows one example of stress analysis results in the vicinity of the inner rib of the magnetic pole portion of the present embodiment and the reference example;​

[0013] Figure 5 is a diagram schematically showing the main directions of forces acting on the magnetic pole portion;

[0014] Figure 6 is Figure 2 an enlarged view of the vicinity of the inner side rib of

[0015] Figure 7 is a contour map showing one example of stress analysis results in the vicinity of the inner side rib of the magnetic pole portion of the present embodiment and another reference example;

[0016] Figure 8 is a diagram showing a modification of Figure 2

[0017] Figure 9 is a diagram showing another modification of Figure 2

[0018] Figure 10 is a diagram showing another reference example of Figure 2 DETAILED DESCRIPTION

[0019] Hereinafter, an embodiment of the present application will be described with reference to Figures 1-10 An embodiment of the present application is a rotating electric machine mounted on a hybrid vehicle or an electric vehicle, which can be used as a motor for driving a vehicle and as a generator. The rotating electric machine can also be mounted on a non-vehicle for various uses.

[0020] Figure 1 is a cross-sectional view perpendicular to the axis CL0 showing the main part structure of the rotating electric machine of the embodiment of the present application. Hereinafter, the direction of extension of the axis CL0 is defined as the axial direction, the direction extending radially from the center of the axis CL0 is defined as the radial direction, and the direction along the circle centered on the axis CL0 is defined as the circumferential direction. As shown in Figure 1 The rotating electric machine 100 has a rotor 1 rotating around the axis CL0 and a stator 2 arranged so as to surround the outer circumferential surface la of the rotor 1. A gap of a prescribed length is provided between the outer circumferential surface la of the rotor 1 and the inner circumferential surface of the stator 2 along the entire circumference.

[0021] The rotor 1 has a substantially circular ring-shaped rotor core 10 centered on the axis CL0 and a plurality of magnetic pole portions 30 formed on the circumferential direction of the rotor core 10. A rotor shaft 101, for example, constituting an output shaft of the rotating electric machine 100, is fitted to the inner circumferential surface 10a of the rotor core 10, and the rotor 1 rotates integrally with the rotor shaft 101. The outer circumferential surface la of the rotor 1 corresponds to the outer circumferential surface of the rotor core 10. The rotor core 10 is formed by laminating a plurality of electromagnetic steel sheets made of a magnetic material in the axial direction.

[0022] ​​​Multiple magnetic pole sections 30 are evenly spaced in the circumferential direction. Figure 1 In this example, six magnetic pole sections 30 are arranged in units of 60°. Each magnetic pole section 30 has multiple (six in the figure) magnet receiving holes 31 formed in the rotor core 10 and multiple permanent magnets 41 housed in the multiple magnet receiving holes 31. Figure 1 The diagram shows the magnetic pole centerline CL1, which extends radially from the axis CL0 through the circumferential center of the magnetic pole section 30. The magnetic pole centerline CL1 corresponds to the d-axis (the main magnetic flux direction of the permanent magnet 41) of the magnetic pole section 30. The magnetic pole centerline CL1 is set in each of the plurality of magnetic pole sections 30. The boundary of the plurality of magnetic pole sections 30 corresponds to the q-axis, which is electrically and magnetically orthogonal to the d-axis.

[0023] The stator 2 has a generally annular stator core 20 centered on an axis CL0 and coils 21 mounted on the stator core 20. The stator core 20 is arranged radially at a predetermined interval from the outer circumferential surface 1a of the rotor 1. The stator core 20 is constructed by stacking multiple sheets of electromagnetic steel, which are magnetic materials. Although a portion of the illustration is omitted, a plurality of circumferential teeth 22 are provided at equal intervals along the entire circumference of the inner circumference of the stator core 20, pointing radially inward. Slots are formed between adjacent teeth 22 in the circumferential direction. The coils 21 are, for example, formed by windings wound around the teeth 22.

[0024] When current flows through coil 21, a magnetic field is generated in stator 2. This magnetic field interacts with the magnetic field generated by the permanent magnet 41 of the magnetic pole section 30 of rotor 1, thereby causing rotor 1 to rotate. Specifically, rotor 1 rotates using permanent magnet torque and reluctance torque.

[0025] Figure 2 This shows the structure of a single magnetic pole section 30. Figure 1 Enlarged view of the main parts. (See image below.) Figure 2 As shown, the magnetic pole section 30 has a plurality of magnet receiving holes 31 that penetrate the rotor core 10 axially. The plurality of magnet receiving holes 31 includes three magnet receiving holes (referred to as inner magnet receiving holes) located on the inner circumference and three magnet receiving holes (referred to as outer magnet receiving holes) located on the outer circumference. These plurality of magnet receiving holes 31 are generally rectangular in shape in a cross section perpendicular to the axis CL0 and are symmetrically arranged about the magnetic pole centerline CL1.

[0026] More specifically, the inner side magnet housing holes have a first magnet housing hole (inner side central housing hole) 311 disposed on the pole center line CL1, second and third magnet housing holes 312 and 313 (a pair of inner side inclined housing holes) disposed on both sides in the circumferential direction of the first magnet housing hole 311. The first magnet housing hole 311 extends in the circumferential direction in a manner orthogonal to the pole center line CL1. The second and third magnet housing holes 312 and 313 respectively extend obliquely with respect to the pole center line CL1 in a manner that faces the radially outer side as it moves away from the pole center line CL1. Hereinafter, the first, second, and third magnet housing holes 311, 312, and 313 are sometimes referred to as inner side magnet housing holes 311 to 313.

[0027] The outer side magnet housing holes have a fourth magnet housing hole (outer side central housing hole) 314 disposed on the pole center line CL1, fifth and sixth magnet housing holes 315 and 316 (a pair of outer side inclined housing holes) disposed on both sides in the circumferential direction of the fourth magnet housing hole 314. The fourth magnet housing hole 314 extends in the circumferential direction in a manner orthogonal to the pole center line CL1. The fifth and sixth magnet housing holes 315 and 316 respectively extend obliquely with respect to the pole center line CL1 in a manner that faces the radially outer side as it moves away from the pole center line CL1. Hereinafter, the fourth, fifth, and sixth magnet housing holes 314, 315, and 316 are sometimes referred to as outer side magnet housing holes 314 to 316.

[0028] The outer side magnet housing holes 314 to 316 are respectively located radially outward of the inner side magnet housing holes 311 to 313. In a cross section perpendicular to the axis line CL0, the long side direction of each magnet housing hole 31 is referred to as the width, and the short side direction is referred to as the height. The heights of the magnet housing holes 311 to 316 are the same or substantially the same as each other. The widths of the inner side magnet housing holes 311 to 313 are the same or substantially the same as each other. The widths of the outer side magnet housing holes 314 to 316 are the same or substantially the same as each other. The widths of the inner side magnet housing holes 311 to 313 are longer than the widths of the outer side magnet housing holes 314 to 316.

[0029] The permanent magnets 41 include a first permanent magnet 411 housed in the first magnet housing hole 311, a second permanent magnet 412 housed in the second magnet housing hole 312, a third permanent magnet 413 housed in the third magnet housing hole 313, a fourth permanent magnet 414 housed in the fourth magnet housing hole 314, a fifth permanent magnet 415 housed in the fifth magnet housing hole 315, and a sixth permanent magnet 416 housed in the sixth magnet housing hole 316. The permanent magnets 41 can use various types of materials such as neodymium magnets, ferrite magnets, and the like.

[0030] The first permanent magnet 411, the second permanent magnet 412, and the third permanent magnet 413 are sometimes referred to as inner permanent magnets 411 to 413, and the fourth permanent magnet 414, the fifth permanent magnet 415, and the sixth permanent magnet 416 are sometimes referred to as outer permanent magnets 414 to 416. The inner permanent magnets 411 to 413 are the same or substantially the same shape as each other. The outer permanent magnets 414 to 416 are the same or substantially the same shape as each other.

[0031] The plurality of permanent magnets 41 are formed in a flat plate shape elongated in the axial direction in a substantially rectangular shape corresponding to the magnet housing hole 31 in a front view observed along the axis line CL0. In a cross section perpendicular to the axis line CL0, the long side direction of each permanent magnet 41 is referred to as the width, and the short side direction is referred to as the thickness. The width of the inner permanent magnets 411 to 413 is longer than the width of the outer permanent magnets 414 to 416. The thickness of the inner permanent magnets 411 to 413 is equal to or substantially equal to the thickness of the outer permanent magnets 414 to 416. The thickness of the inner permanent magnets 411 to 413 can also be thicker than the thickness of the outer permanent magnets 414 to 416.

[0032] The permanent magnets 41 are symmetrically configured as a whole with respect to a center line CL2 extending in the thickness direction through the center of the width direction. The center line CL2 of the first permanent magnet 411 and the center line CL2 of the fourth permanent magnet 414 coincide with the pole center line CL1. The plurality of permanent magnets 41 are magnetized in the thickness direction. For example, the end faces in the thickness direction on the radially outer side of the plurality of permanent magnets 41 are each magnetized to an N pole, and the end faces in the thickness direction on the radially inner side are each magnetized to an S pole. The directions of magnetization are opposite in the circumferentially adjacent pole portions 30.

[0033] In the rotor core 10, a magnetic flux barrier 33 is formed in connection with the magnet housing hole 31. The magnetic flux barrier 33 is in abutment with a pair of end faces 41a, 41b of the width direction both end portions of the permanent magnet 41, and extends toward the width direction outer side of the permanent magnet 32. In addition, a part of the magnetic flux barrier 33, particularly, the length in the radial direction (the length in the thickness direction of the permanent magnet 41) of the magnetic flux barrier 33 in abutment with the end faces 41a, 41b of the first permanent magnet 411, the magnetic flux barrier 33 in abutment with the end face 41b on the pole center side of the second permanent magnet 412, and the magnetic flux barrier 33 in abutment with the end face 41a on the pole center side of the third permanent magnet 413 is longer than the thickness of the permanent magnet 41.

[0034] The magnetic flux barrier 33 is an air layer having a larger magnetic resistance than the rotor core 10. By providing the magnetic flux barrier 33, it is possible to suppress the magnetic flux generated by the permanent magnet 41 from short-circuiting on the rotor side. It is also possible to fill the magnetic flux barrier 33 with a resin having a lower magnetic permeability than the rotor core 10, and to provide the magnetic flux barrier 33 as a resin layer.

[0035] In the rotor core 10, ribs 35 (referred to as inner side ribs) are provided between the first magnet accommodating hole 311 and the second magnet accommodating hole 312, and between the first magnet accommodating hole 311 and the third magnet accommodating hole 313. More specifically, the inner side ribs 35 are provided between the magnetic flux barrier 33 adjacent to the first magnet accommodating hole 311 and the magnetic flux barrier 33 adjacent to the second magnet accommodating hole 312, and between the magnetic flux barrier 33 adjacent to the first magnet accommodating hole 311 and the magnetic flux barrier 33 adjacent to the third magnet accommodating hole 313. Ribs are also provided between the magnetic flux barrier 33 adjacent to the second magnet accommodating hole 312 and the outer circumferential surface la of the rotor core 10, and between the magnetic flux barrier 33 adjacent to the third magnet accommodating hole 313 and the outer circumferential surface la of the rotor core 10.

[0036] In addition, in the rotor core 10, ribs 36 (referred to as outer side ribs) are provided between the fourth magnet accommodating hole 314 and the fifth magnet accommodating hole 315, and between the fourth magnet accommodating hole 314 and the sixth magnet accommodating hole 316. More specifically, the outer side ribs 36 are provided between the magnetic flux barrier 33 adjacent to the fourth magnet accommodating hole 314 and the magnetic flux barrier 33 adjacent to the fifth magnet accommodating hole 315, and between the magnetic flux barrier 33 adjacent to the fourth magnet accommodating hole 314 and the magnetic flux barrier 33 adjacent to the sixth magnet accommodating hole 316. Ribs are also provided between the magnetic flux barrier 33 adjacent to the fifth magnet accommodating hole 315 and the outer circumferential surface la of the rotor core 10, and between the magnetic flux barrier 33 adjacent to the sixth magnet accommodating hole 316 and the outer circumferential surface la of the rotor core 10.

[0037] The inner side ribs 35 extend in the substantially radial direction in a state in which the distance, i.e., the width, between the adjacent pair of magnetic flux barriers 33, 33 is constant or substantially constant. Strictly speaking, they extend obliquely in the radial direction outwardly in a manner so as to be directed toward the pole center line CL1. The outer side ribs 36 also extend in the substantially radial direction in a state in which the width is constant or substantially constant. Strictly speaking, they extend obliquely in the radial direction outwardly in a manner so as to be directed toward the pole center line CL1. The width of the inner side ribs 35 is wider than the width of the outer side ribs 36.

[0038] Figure 3This diagram shows an example of the magnetic pole section 30A as a reference example of this embodiment. In this reference example, there is no magnet receiving hole on the magnetic pole centerline CL1, and magnet receiving holes 31A are provided on both the inner and outer circumferential sides of the rotor core 10A, respectively, on both sides of the magnetic pole centerline CL1. A permanent magnet 41A is received in the magnet receiving hole 31A. Ribs (center ribs) 35A and 36A are provided along the magnetic pole centerline CL1 on the rotor core 10A. In this structure, when the rotor 1 rotates at high speeds (for example, when the rotor 1 rotates at speeds of 20,000 rpm or higher), in order to resist centrifugal force and ensure sufficient strength of the rotor core 10A, the center ribs 35A and 36A need to be set higher than... Figure 3 The magnets are thicker. As a result, leakage flux increases, leading to a decrease in the performance of the rotating electric machine. To suppress this performance degradation, the amount of magnets needs to be increased.

[0039] In contrast, in this embodiment, such as Figure 2 As shown, a magnet receiving hole 31 is provided on the magnetic pole center line CL1 of the rotor core 10, and magnet receiving holes 31 are provided on both sides of the central magnet receiving hole 31 via inner ribs 35 and outer ribs 36. Thus, multiple inner ribs 35 and outer ribs 36 are provided on the inner diameter side and outer diameter side of the rotor core 10, respectively, thus compared to the case where a single central rib 35A, 36A is provided ( Figure 3 In comparison, the overall cross-sectional area of ​​the inner rib 35 and the outer rib 36 is increased. As a result, when the rotor 1 is rotating at high speed, the thickness of the ribs 35 and 36 can be set to be thinner compared to the case where the center ribs 35A and 36A are provided. This helps to suppress performance degradation while ensuring sufficient strength of the rotor core 10.

[0040] Figure 2 In this diagram, θ1 represents the angle between the extension line L21 of the center line CL2 of the second permanent magnet 412 and the third permanent magnet 413 (for simplicity, only the extension line L21 of the second permanent magnet 412 is shown) and the center line CL1 of the magnetic pole. Similarly, θ2 represents the angle between the extension line L22 of the center line CL2 of the fifth permanent magnet 415 and the sixth permanent magnet 416 (for simplicity, only the extension line CL22 of the fifth permanent magnet 415 is shown) and the center line CL1 of the magnetic pole. Extension line L21 corresponds to the direction of the main magnetic flux of permanent magnets 412 and 413, and extension line L22 corresponds to the direction of the main magnetic flux of permanent magnets 415 and 416. Angle θ1 is larger than angle θ2.

[0041] In this embodiment, as such, the permanent magnet 41 is disposed on the pole center line CL1, and the permanent magnets 41 are disposed at an angle θ1 > θ2 on both sides thereof. Thus, the magnetic flux from the permanent magnet 41 can be concentrated on the rotation center side (the axis CL0 side) of the rotor 1, thereby increasing the magnetic flux on the d-axis, and the saliency of the pole portion 30 can be increased. That is, the saliency ratio can be increased. As a result, compared with the case where θ1 ≤ θ2, the torque of the rotor 1 can be increased. Further, by setting θ1 > θ2, the length in the radial direction between the inner magnet housing holes 311 to 313 and the outer magnet housing holes 314 to 316 increases as it goes outward in the circumferential direction toward the pole center line CL1. Thus, the magnetic flux from the stator 2 can be prevented from being concentrated to cause magnetic saturation.

[0042] Further, in Figure 2 , θ3 denotes the angle of the reference line L23 extending along the inner rib 35 through the width direction center of the inner rib 35 with respect to the pole center line CL1. Further, θ4 denotes the angle of the reference line L24 extending along the outer rib 36 through the width direction center of the outer rib 36 with respect to the pole center line CL1. The angle θ3 is larger than the angle θ4. That is, the angle of the direction in which the ribs 35, 36 extend (rib angle) is larger for the inner rib 35 than for the outer rib 36.

[0043] The stress occurring in the rotor core 10 is likely to be the largest near the inner rib 35. Figure 4 is an example of a contour map showing the results of stress analysis near the inner rib 35. In the drawing, on the left side of the pole center line CL1, an example of the results of analysis of the rotor core 10 of this embodiment is shown in which the rib angle θ3 along the reference line L23 is larger than the rib angle θ4 along the reference line L24 Figure 2 ) on the right side of the pole center line CL1, an example of the results of analysis of the rotor core in the case where θ3 = θ4 is set as a reference example, that is, in the case where the inner rib 35B extends along the reference line L23B parallel to the pole center line CL1. In the reference example, the magnetic flux barrier is not lengthened in the radial direction. For convenience, in Figure 4 , the region A in which the maximum stress of a prescribed value or more occurs and the region B in which a stress one level lower than the maximum stress occurs are indicated by hatching.

[0044] As Figure 4 shown, compared with the reference example, in this embodiment, stress occurs uniformly in the inner rib 35. Thus, the stress concentration near the inner rib 35 can be alleviated, and high rotation of the rotor 1 can be achieved.

[0045] Figure 5 is a schematic view showing the main forces acting on the rotor core 10. As Figure 5As shown, a centrifugal force acts radially on the rotor core 10, and a reaction force of this centrifugal force acts circumferentially. Therefore, a tensile force F0 acts circumferentially on the inner circumference of the rotor core 10. Thus, a centrifugal force mainly acts near the outer rib 36, while a circumferential tensile force F0 acts near the inner rib 35 in addition to the centrifugal force. Therefore, a force as indicated by arrow F1 acts along the direction of extension of the outer rib 36, and a force as indicated by arrow F2 acts along the direction of extension of the inner rib 35. Thus, the force acts uniformly on the inner rib 35, resulting in... Figure 4 As shown, this can alleviate the stress concentration of the inner rib 35.

[0046] Figure 6 This is an enlarged view of the inner rib 35 on the side of the second permanent magnet 412. Figure 6 In the diagram, symbol 331 represents the magnetic flux barrier 33 adjacent to the end face 41a of the first permanent magnet 411, and symbol 332 represents the magnetic flux barrier 33 adjacent to the end face 41b of the second permanent magnet 412. For example... Figure 6 As shown, magnetic flux barriers 331 and 332 protrude outwards from the magnet receiving holes 311 and 312 in the thickness direction of the permanent magnets 411 and 412. Along the baseline L23 ( Figure 2 The length L332 of the magnetic flux barrier 332 is longer than the length L331 of the magnetic flux barrier 331. The magnetic flux barriers 331 and 332 are formed asymmetrically about the baseline L23.

[0047] Figure 7 This is a contour plot showing an example of the stress analysis results near the inner rib 35. Figure 7 also with Figure 4 Similarly, to the left of the magnetic pole centerline CL1, an example of the analysis results of the rotor core 10 of this embodiment is shown; to the right of the magnetic pole centerline CL1, an example of the analysis results of the rotor core as a reference example is shown. Figure 7 In the reference example, the inner rib 35C is provided in the same manner as this embodiment, with θ3 > θ4. However, in the reference example, unlike this embodiment, the magnetic flux barrier is not lengthened in the radial direction (thickness direction of the permanent magnet 41).

[0048] like Figure 7 As shown, compared to the reference example, in this embodiment, stress is uniformly generated in the inner rib 35. This alleviates stress concentration near the inner rib 35, enabling high rotational speed of the rotor 1.

[0049] Thus, in the present embodiment, the magnetic flux barriers 331, 332 are formed longer in the radial direction than the magnet housing holes 31, so that the force can be absorbed by the gap (magnetic flux barrier), whereby stress concentration can be mitigated. In the present embodiment, the magnetic flux barrier 332 is made longer than the magnetic flux barrier 331, and the magnetic flux barriers 331, 332 are configured asymmetrically with respect to the reference line L23. More specifically, the magnetic flux barrier 332 on the side of the force in the direction of the arrow F2 is made longer than the magnetic flux barrier 331 on the other side. Thereby, stress concentration can be further mitigated. Figure 5

[0050] In the above, the inner magnet housing holes 311 to 313 and the outer magnet housing holes 314 to 316 are provided in the pole portion 30 of the rotor 1. That is, two layers of magnet housing holes 31 are provided in the radial direction, but three or more layers of magnet housing holes 31 can also be provided in the radial direction. Figure 8 is a view showing an example of the pole portion 30 in which three layers of magnet housing holes 31 are provided in the pole portion 30. Figure 8 In the above, the inner magnet housing holes 311 to 313 and the outer magnet housing holes 314 to 316 are provided in the pole portion 30 of the rotor 1. That is, two layers of magnet housing holes 31 are provided in the radial direction, but three or more layers of magnet housing holes 31 can also be provided in the radial direction.

[0051] As shown in Figure 8 , in the rotor core 10, the seventh magnet housing hole 317, the eighth magnet housing hole 318, and the ninth magnet housing hole 319 are provided symmetrically with respect to the pole center line CL1 on the radially inner side of the first magnet housing hole 311, the second magnet housing hole 312, and the third magnet housing hole 313. More specifically, the seventh magnet housing hole 317 (third central housing hole) is provided extending in the circumferential direction in a manner orthogonal to the pole center line CL1 on the pole center line CL1. The eighth magnet housing hole 318 and the ninth magnet housing hole 319 (a pair of third inclined housing holes) are respectively provided extending obliquely with respect to the pole center line CL1 in a manner that moves toward the radially outer side as it moves away from the pole center line CL1.

[0052] The seventh magnet 417, the eighth magnet 418, and the ninth magnet 419 are housed in the seventh magnet housing hole 317, the eighth magnet housing hole 318, and the ninth magnet housing hole 319, respectively. These magnets 417 to 419 are the same as the inner magnets 411 to 413 and the outer magnets 414 to 416, and correspond to the magnet housing holes 31 in a substantially rectangular shape in the front view when viewed along the axis CL0, and are the same or substantially the same shape as each other. The width of the magnets 417 to 419 is longer than the width of the inner magnets 411 to 413. That is, the magnets 411 to 419 are longer toward the radially inner side. The width direction of each magnet 411 to 419 is the same or substantially the same as the extending direction of the magnetic induction lines 10b.

[0053] Figure 8 ​The angle θ5 is an angle between the extension line L25 of each center line CL2 of the eighth permanent magnet 418 and the ninth permanent magnet 419 and the pole center line CL1. The angle θ5 is larger than the angle θ1 between the extension line L21 and the pole center line CL1. Figure 2 ) That is, the angles θ1, θ2, θ5 between the extension lines L21, L22, L25 and the pole center line CL1 gradually increase toward the radially inner side (θ2 < θ1 < θ5).

[0054] Thus, the magnetic flux from the permanent magnets 41 can be concentrated on the rotation center side (the axis CL0 side) of the rotor 1, thereby increasing the magnetic flux on the d-axis and improving the saliency of the pole portion 30. In addition, by increasing the number of layers of the permanent magnets 41, a larger torque increase can be achieved.

[0055] In the above, three magnet housing holes 31 are provided in each layer of the pole portion 30 of the rotor 1, but the number of magnet housing holes 31 in each layer can be five or more as long as it is an odd number. Figure 9 is a view showing an example of the pole portion 30 in which five magnet housing holes 31 are provided on the inner and outer circumferential sides of the pole portion 30. In Figure 9 , the magnetic induction lines 10b from the stator 2 are shown as in Figure 8 , and the illustration of the flux barrier 33 is omitted.

[0056] As shown in Figure 9 , in the rotor core 10, the eleventh magnet housing hole 3111 and the twelfth magnet housing hole 3112 are provided symmetrically with respect to the pole center line CL1 on the circumferential outer side of the second magnet housing hole 312 and the third magnet housing hole 313. Further, the thirteenth magnet housing hole 3113 and the fourteenth magnet housing hole 3114 are provided symmetrically with respect to the pole center line CL1 on the circumferential outer side of the fifth magnet housing hole 315 and the sixth magnet housing hole 316. The eleventh magnet housing hole 3111 and the twelfth magnet housing hole 3112 are respectively provided so as to extend obliquely with respect to the pole center line CL1 in such a manner that they are directed toward the radially outer side as they move away from the pole center line CL1. The thirteenth magnet housing hole 3113 and the fourteenth magnet housing hole 3114 are respectively provided so as to extend obliquely with respect to the pole center line CL1 in such a manner that they are directed toward the radially outer side as they move away from the pole center line CL1.

[0057] The eleventh magnet housing hole 3111, the twelfth magnet housing hole 3112, the thirteenth magnet housing hole 3113, and the fourteenth magnet housing hole 3114 house the eleventh permanent magnet 4111, the twelfth permanent magnet 4112, the thirteenth permanent magnet 4113, and the fourteenth permanent magnet 4114, respectively. The eleventh permanent magnet 4111 and the twelfth permanent magnet 4112 each have the same or substantially the same shape as the inner permanent magnets 411 to 413 on the inner side in the circumferential direction thereof. The thirteenth permanent magnet 4113 and the fourteenth permanent magnet 4114 have the same or substantially the same shape as the outer permanent magnets 414 to 416 on the inner side in the circumferential direction thereof. The width direction of each of the permanent magnets 4111 to 4114 is the same or substantially the same as the extension direction of the magnetic induction line 10b.

[0058] Figure 9 The angle θ7 represents the angle of the extension line L27 of each center line CL2 of the eleventh permanent magnet 4111 and the twelfth permanent magnet 4112 with respect to the pole center line CL1. The angle θ8 represents the angle of the extension line L28 of each center line CL2 of the thirteenth permanent magnet 4113 and the fourteenth permanent magnet 4114 with respect to the pole center line CL1.

[0059] The angle θ7 is larger than the angle θ8 (θ7 > θ8). The angle θ7 is also larger than the angle θ1 defined by the extension line L21 of the permanent magnets 412 and 413 on the inner side in the circumferential direction thereof. The angle θ8 is larger than the angle θ2 defined by the extension line L22 of the permanent magnets 415 and 416 on the inner side in the circumferential direction thereof. That is, the angles θ1, θ2, θ7, and θ8 of the extension lines L21, L22, L27, and L28 with respect to the pole center line CL1 gradually increase as they move away from the pole center line CL1 in the circumferential direction (θ1 < θ7, θ2 < θ8).

[0060] Thus, without increasing the number of layers of the permanent magnets 41, it is possible to concentrate the magnetic flux from more permanent magnets 41 on the rotation center side (the axis CL0 side) of the rotor 1, thereby increasing the magnetic flux on the d-axis and improving the saliency of the pole portion 30. The permanent magnets 41 are sometimes referred to as "saliency magnets" or "saliency permanent magnets". Figure 9 The eleventh magnet housing hole 3111 and the twelfth magnet housing hole 3112 are referred to as inner large-inclination housing holes, the thirteenth magnet housing hole 3113 and the fourteenth magnet housing hole 3114 are referred to as outer large-inclination housing holes, the eleventh permanent magnet 4111 and the twelfth permanent magnet 4112 are referred to as inner large-inclination permanent magnets, the thirteenth permanent magnet 4113 and the fourteenth permanent magnet 4114 are referred to as outer large-inclination permanent magnets, the extension line L27 is referred to as an inner reference line, and the extension line L28 is referred to as an outer reference line.

[0061] In the present embodiment, the magnetic pole portion 30 is provided with 2 or more layers in the radial direction and 3 or more permanent magnets 41 in each layer. Thus, demagnetization of the permanent magnets 41 due to the reverse magnetic field from the stator 2 can be suppressed. Figure 10 is Figure 2 a reference example, is a diagram showing an example of the structure of the magnetic pole portion 30 in a case where the number of the permanent magnets 41 on the inner side and the outer side is different and the outer side permanent magnets are not provided on the magnetic pole center line CL1. As shown in Figure 10 , in a case where the number of the permanent magnets 41 in each layer is different, the permeance coefficient decreases due to the provision of the permanent magnets 41 and the ribs 37 on the straight line extending from the stator 2, and the influence of the reverse magnetic field is likely to be received. Thus, the demagnetization resistance of the permanent magnets 41 can decrease. In view of this, as in the present embodiment, it is preferable to make the number of the permanent magnets 41 in each layer equal.

[0062] By adopting the present embodiment, the following effects can be achieved.

[0063] (1) The rotary electric machine 100 includes a rotor 1 that rotates around an axis line CL0 and a stator 2 that is provided around the outer circumferential surface la of the rotor 1 and generates a rotating magnetic field that acts on the rotor 1 Figure 1 ). The rotor 1 includes a rotor core 10 provided with a magnet housing hole 31 that extends in the axial direction and a permanent magnet 41 housed in the magnet housing hole 31, and is composed of a plurality of magnetic pole portions 30 in the circumferential direction Figure 2 ). The magnet housing hole 31 includes a plurality of magnet housing holes 311 to 316 that are provided symmetrically with respect to a magnetic pole center line CL1 that extends radially from the axis line CL0, for each of the plurality of magnetic pole portions 30 in the circumferential direction Figure 2 ). The plurality of magnet housing holes 311 to 316 include a first magnet housing hole 311 and a fourth magnet housing hole 314 that extend to the inner side and the outer side in the radial direction, respectively, in a manner orthogonal to the magnetic pole center line CL1, a second magnet housing hole 312 and a third magnet housing hole 313 that are provided on both sides in the circumferential direction of the first magnet housing hole 311 and extend obliquely with respect to the magnetic pole center line CL1 in a manner that moves toward the outer side in the radial direction as it moves away from the magnetic pole center line CL1, and a fifth magnet housing hole 315 and a sixth magnet housing hole 316 that are provided on both sides in the circumferential direction of the fourth magnet housing hole 314 and extend obliquely with respect to the magnetic pole center line CL1 in a manner that moves toward the outer side in the radial direction as it moves away from the magnetic pole center line CL1 Figure 2 . The permanent magnet 41 is housed in the plurality of magnet housing holes 311 to 316, and includes a plurality of permanent magnets 411 to 416 that have a width in the long side direction and a thickness in the short side direction Figure 2). The plurality of permanent magnets 411 to 416 include the first permanent magnet 411 housed in the first magnet housing hole 311, the second permanent magnet 412 and the third permanent magnet 413 housed in the second magnet housing hole 312 and the third magnet housing hole 313, the fourth permanent magnet 414 housed in the fourth magnet housing hole 314, the fifth permanent magnet 415 and the sixth permanent magnet 416 housed in the fifth magnet housing hole 315 and the sixth magnet housing hole 316 Figure 2 ). The rotor core 10 has an inner side rib 35 disposed between the first magnet housing hole 311 and the second magnet housing hole 312 and the third magnet housing hole 313, and an outer side rib 36 disposed between the fourth magnet housing hole 314 and the fifth magnet housing hole 315 and the sixth magnet housing hole 316 Figure 2 ). An angle θ1 of an extension line L21 extending in the thickness direction from the center in the width direction of the second permanent magnet 412 and the third permanent magnet 413 with respect to the pole center line CL1 is larger than an angle θ2 of an extension line L22 extending in the thickness direction from the center in the width direction of the fifth permanent magnet 415 and the sixth permanent magnet 416 with respect to the pole center line CL1 Figure 2 ).

[0064] With this structure, the plurality of inner side ribs 35 and the plurality of outer side ribs 36 are disposed obliquely with respect to the pole center line CL1 on both sides in the circumferential direction of the pole center line CL1. Therefore, the thickness of the ribs 35, 36 can be made thinner than in the case where the center ribs 35A, 36A are disposed (see Figure 3 ), and the magnetic flux leakage can be suppressed. In addition, the permanent magnets 412, 413, 415, 416 on both sides in the circumferential direction of the pole center line CL1 are disposed obliquely in a manner that θ1 > θ2, and therefore the saliency of the rotor 1 is increased. Thus, the strength of the rotor 1 can be ensured while the maximum torque of the rotor 1 is increased.

[0065] (2) The inner side rib 35 is disposed extending along a reference line L23 toward the pole center line CL1 between the first magnet housing hole 311 and the second magnet housing hole 312 and the third magnet housing hole 313 Figure 2 ). The outer side rib 36 is disposed extending along a reference line L24 toward the pole center line CL1 between the fourth magnet housing hole 314 and the fifth magnet housing hole 315 and the sixth magnet housing hole 316 Figure 2 ). An angle θ3 of the reference line L23 with respect to the pole center line CL1 is larger than an angle θ4 of the reference line L24 with respect to the pole center line CL1 Figure 2 ). Thus, the stress concentration of the ribs 35, 36 can be alleviated, and high rotation of the rotor 1 can be achieved.

[0066] (3) In the rotor core 10, further provided across the inner side rib 35 are a magnetic flux barrier 331 that is adjacent to the width direction end of the first magnet housing hole 311 and a magnetic flux barrier 332 that is adjacent to the width direction end of the second magnet housing hole 312 and the third magnet housing hole 313. Figure 6 ). The length of the magnetic flux barrier 332 in the direction in which the inner side rib 35 extends is longer than the length of the magnetic flux barrier 331 in the direction in which the inner side rib 35 extends. Figure 6 ). Thus, stress concentration of the inner side rib 35 can be mitigated, and high rotation of the rotor 1 can be achieved.

[0067] (4) The plurality of magnet housing holes 31 further include a seventh magnet housing hole 317 that is provided further radially inward than the first magnet housing hole 311 in a manner that is orthogonal to the pole center line CL1, an eighth magnet housing hole 318 and a ninth magnet housing hole 319 that are provided on both circumferential sides of the seventh magnet housing hole 317 and that are provided in a manner that is inclined with respect to the pole center line CL1 so as to be directed radially outward as they are distanced from the pole center line CL1. Figure 8 ). The plurality of permanent magnets 41 further include a seventh permanent magnet 417 that is housed in the seventh magnet housing hole 317, an eighth permanent magnet 418 and a ninth permanent magnet 419 that are housed in the eighth magnet housing hole 318 and the ninth magnet housing hole 319. Figure 8 ). Thus, sufficient strength of the rotor 1 can be ensured while the maximum torque is improved. Figure 8

[0068] The present embodiment can be modified in various ways. Hereinafter, several modified examples will be described. In the above-described embodiment, the plurality of magnet housing holes 31 are provided symmetrically with respect to the pole center line CL1 in the rotor core 10. That is, the first magnet housing hole 311 is provided as an inner side central housing hole, the second magnet housing hole 312 and the third magnet housing hole 313 are provided as a pair of inner side inclined housing holes, the fourth magnet housing hole 314 is provided as an outer side central housing hole, the fifth magnet housing hole 315 and the sixth magnet housing hole 316 are provided as a pair of outer side inclined housing holes, the seventh magnet housing hole 317 is provided as a third central housing hole, and the eighth magnet housing hole 318 and the ninth magnet housing hole 319 are provided as a pair of third inclined housing holes. However, as long as a plurality of central housing holes are provided in the radial direction in a manner that is orthogonal to the pole center line CL1 and a plurality of inclined housing holes are provided on both circumferential sides of each of the central housing holes in a manner that is inclined with respect to the pole center line CL1 so as to be directed radially outward as they are distanced from the pole center line CL1, the number and arrangement of the magnet housing holes are not limited to those described above.​

[0069] In the above embodiment, the plurality of magnet housing holes 31 are configured with a plurality of permanent magnets 41 in a substantially rectangular shape, and the plurality of permanent magnets 41 include a first permanent magnet 411 as an inner central permanent magnet, a second permanent magnet 412 and a third permanent magnet 413 as a pair of inner inclined permanent magnets, a fourth permanent magnet 414 as an outer central permanent magnet, a fifth permanent magnet 415 and a sixth permanent magnet 416 as a pair of outer inclined permanent magnets, a seventh permanent magnet 417 as a third central permanent magnet, and an eighth permanent magnet 418 and a ninth permanent magnet 419 as a pair of third inclined permanent magnets. However, the shape and number of the permanent magnets 41 are not limited to the above. The permanent magnets 41 can also be configured in a circular arc shape.

[0070] Regardless of whether the permanent magnets 41 are configured in a substantially rectangular shape or a circular arc shape, as long as the angle θ1 of the extension line L21 (first reference line) extending in the thickness direction from the center in the width direction of the inner inclined permanent magnet with respect to the pole center line CL1 is larger than the angle θ2 of the extension line L22 (second reference line) extending in the thickness direction from the center in the width direction of the outer inclined permanent magnet with respect to the pole center line CL1, it is acceptable. In addition, in the case where a third central permanent magnet and a third inclined permanent magnet are provided, as long as the angle θ5 of the extension line L25 (fifth reference line) extending in the thickness direction from the center in the width direction of the third inclined permanent magnet with respect to the pole center line CL1 is larger than the angle θ1 of the extension line L21 with respect to the pole center line CL1, it is acceptable.

[0071] In the above embodiment, in the rotor core 10, the inner rib 35 is provided along the reference line L23 (third reference line) toward the pole center line CL1 between the first magnet housing hole 311 and the second magnet housing hole 312 and the third magnet housing hole 313, and the outer rib 36 is provided along the reference line L24 (fourth reference line) toward the pole center line CL1 between the fourth magnet housing hole 314 and the fifth magnet housing hole 315 and the sixth magnet housing hole 316. However, as long as the angle θ3 of the reference line L23 with respect to the pole center line CL1 is larger than the angle θ4 of the reference line L24 with respect to the pole center line CL1, the structure of the inner rib and the outer rib is not limited to the above. In the above embodiment ( Figure 6 ), the magnetic flux barrier 332 (second magnetic flux barrier) is provided longer than the magnetic flux barrier 331 (first magnetic flux barrier) in the circumferential direction of the inner rib 35, but the structure of the magnetic flux barrier is not limited to the above.

[0072] One or more of the above embodiments and modified examples can be arbitrarily combined, and each modified example can be combined with each other.

[0073] With the present application, it is possible to ensure sufficient strength of the rotor while improving the maximum torque of the rotor.

[0074] The application has been described above with reference to preferred embodiments. However, those skilled in the art will understand that various modifications and changes can be made without departing from the scope of the disclosure as set forth in the claims.

Claims

1. A rotary electric machine, which is a rotary electric machine (100) provided with a rotor (1) that rotates around an axis line (CL0) and a stator (2) that is disposed around an outer peripheral surface (la) of the rotor (1) and generates a rotating magnetic field that acts on the rotor (1), characterized by the rotor (1) has a rotor core (10) provided with a magnet housing hole (31) that extends in an axial direction and a permanent magnet (41) that is housed in the magnet housing hole (31), and is composed of a plurality of magnetic pole portions (30) in a circumferential direction, the magnet housing hole (31) includes a plurality of magnet housing holes that are symmetrically disposed with respect to a magnetic pole center line (CL1) that extends radially from the axis line (CL0) for each of the plurality of magnetic pole portions (30) in the circumferential direction, the plurality of magnet housing holes include: an inner central housing hole (311) and an outer central housing hole (314) that are respectively disposed extending to a radially inner side and a radially outer side in a manner orthogonal to the magnetic pole center line (CL1); a pair of inner inclined housing holes (312, 313) that are disposed on both sides in the circumferential direction of the inner central housing hole (311) and are disposed extending obliquely with respect to the magnetic pole center line (CL1) in a manner toward the radially outer side as they move away from the magnetic pole center line (CL1); a pair of outer inclined housing holes (315, 316) that are disposed on both sides in the circumferential direction of the outer central housing hole (314) and are disposed extending obliquely with respect to the magnetic pole center line (CL1) in a manner toward the radially outer side as they move away from the magnetic pole center line (CL1), the permanent magnet (41) includes a plurality of permanent magnets that are housed in the plurality of magnet housing holes, have a width in a long side direction and a thickness in a short side direction, the plurality of permanent magnets include an inner central permanent magnet (411) that is housed in the inner central housing hole (311), a pair of inner inclined permanent magnets (412, 413) that are housed in the pair of inner inclined housing holes (312, 313), an outer central permanent magnet (414) that is housed in the outer central housing hole (314), and a pair of outer inclined permanent magnets (415, 416) that are housed in the pair of outer inclined housing holes (315, 316), the rotor core (10) has an inner rib (35) that is disposed between the inner central housing hole (311) and the pair of inner inclined housing holes (312, 313), and an outer rib (36) that is disposed between the outer central housing hole (314) and the pair of outer inclined housing holes (315, 316), an included angle (θ1) between a first reference line (L21) that extends in the thickness direction from the center in the width direction of the pair of inner inclined permanent magnets (412, 413) and the magnetic pole center line (CL1) is larger than an included angle (θ2) between a second reference line (L22) that extends in the thickness direction from the center in the width direction of the pair of outer inclined permanent magnets (415, 416) and the magnetic pole center line (CL1).

2. The rotary electric machine according to claim 1, characterized by The inner side rib (35) is provided extending along a third reference line (L23) toward the magnetic pole center line (CL1) between the inner side central accommodation hole (311) and the pair of inner side inclined accommodation holes (312, 313), The outer side rib (36) is provided extending along a fourth reference line (L24) toward the magnetic pole center line (CL1) between the outer side central accommodation hole (314) and the pair of outer side inclined accommodation holes (315, 316), The angle (θ3) between the third reference line (L23) and the magnetic pole center line (CL1) is larger than the angle (θ4) between the fourth reference line (L24) and the magnetic pole center line (CL1).

3. The rotary electric machine according to claim 1, wherein a first magnetic flux barrier (331) abutting on a width direction end portion of the inner side central accommodation hole (311) and a second magnetic flux barrier (332) abutting on width direction end portions of the pair of inner side inclined accommodation holes (312, 313) are further provided in the rotor core (10) across the inner side rib (35), the length of the first magnetic flux barrier (331) and the length of the second magnetic flux barrier (332) in the direction in which the inner side rib (35) is provided extending are above the thickness of the permanent magnet (41), and the length of the second magnetic flux barrier (332) in the direction in which the inner side rib (35) is provided extending is longer than the length of the first magnetic flux barrier (331).

4. The rotary electric machine according to any one of claims 1 to 3, wherein the plurality of magnet accommodation holes further include: a third central accommodation hole (317) provided extending radially inward of the inner side central accommodation hole (311) in a manner orthogonal to the magnetic pole center line (CL1); and a pair of third inclined accommodation holes (318, 319) provided on both circumferential sides of the third central accommodation hole (317) in a manner obliquely extending with respect to the magnetic pole center line (CL1) toward a radially outer side as away from the magnetic pole center line (CL1), the plurality of permanent magnets further include a third central permanent magnet (417) accommodated in the third central accommodation hole (317) and a pair of third inclined permanent magnets (418, 419) accommodated in the pair of third inclined accommodation holes (318, 319), a fifth reference line (L25) extending in the thickness direction from the center in the width direction of the pair of third inclined permanent magnets (418, 419) has an angle (θ5) with the magnetic pole center line (CL1) larger than the angle of the first reference line (L21) with the magnetic pole center line (CL1).

5. The rotary electric machine according to any one of claims 1 to 3, wherein the widths of the inner side central permanent magnet (411) and the pair of inner side inclined permanent magnets (412, 413) are longer than the widths of the outer side central permanent magnet (414) and the pair of outer side inclined permanent magnets (415, 416).

6. The rotary electric machine according to any one of claims 1 to 3, wherein The plurality of magnet housing holes further include: a pair of inner large-inclination housing holes (3111, 3112) disposed on both circumferential sides of the pair of inner-inclination housing holes (312, 313) so as to be disposed in an inclined manner with respect to the magnetic pole center line (CL1) in a manner that inclines toward the radially outer side as it moves away from the magnetic pole center line (CL1); and a pair of outer large-inclination housing holes (3113, 3114) disposed on both circumferential sides of the pair of outer-inclination housing holes (315, 316) so as to be disposed in an inclined manner with respect to the magnetic pole center line (CL1) in a manner that inclines toward the radially outer side as it moves away from the magnetic pole center line (CL1), The plurality of permanent magnets further include a pair of inner large-inclination permanent magnets (4111, 4112) housed in the pair of inner large-inclination housing holes (3111, 3112) and a pair of outer large-inclination permanent magnets (4113, 4114) housed in the pair of outer large-inclination housing holes (3113, 3114), An inner reference line (L27) extending in the thickness direction from the width direction center of the pair of inner large-inclination permanent magnets (4111, 4112) has a larger angle (θ7) with respect to the magnetic pole center line (CL1) than the angle (θ1) of the first reference line (L21) with respect to the magnetic pole center line (CL1), and an outer reference line (L28) extending in the thickness direction from the width direction center of the pair of outer large-inclination permanent magnets (4113, 4114) has a larger angle (θ8) with respect to the magnetic pole center line (CL1) than the angle (θ2) of the second reference line (L22) with respect to the magnetic pole center line (CL1).

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