Rotor of a rotating electrical machine

Abstract

To provide a rotor of a rotary electric machine that effectively utilizes a magnetic flux of a permanent magnet to enhance torque density to contribute improved energy efficiency.SOLUTION: In a rotor 101 of a rotary electric machine, a permanent magnet 6 is provided with: a d-axis oriented magnet 9 oriented in a d-axis direction of a rotor core 5; and an obliquely oriented magnet 11 disposed adjacently to the d-axis oriented magnet 9 in the circumferential direction and oriented in a direction inclined to the d-axis and the circumferential direction. A position of an end portion 9a of the d-axis oriented magnet 9 on the side opposite to the rotor core 5 is located closer to the rotor core 5 side than a position of an end portion 11a of the obliquely oriented magnet 11 on the side opposite to the rotor core 5. An outside end portion 9a of the d-axis oriented magnet 9 is equipped with a soft magnetic material 7.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotor for a rotating electrical machine. [Background technology]

[0002] In a rotating electric machine equipped with a rotor having a permanent magnet, when power is supplied to a stator around which a coil is wound, a magnetic flux linkage is formed in the stator. Magnetic attractive and repulsive forces are generated between this magnetic flux linkage and the permanent magnet, causing the rotor to continuously rotate. In order to increase the torque of the rotor, it is effective to concentrate the magnetic flux at the circumferential center of each magnetic pole (the direction of the magnetic flux of each magnetic pole, hereinafter referred to as the d-axis). For the purpose of concentrating this magnetic flux, a technology has been disclosed in which a plurality of permanent magnets are arranged in a Halbach array structure (see, for example, Patent Document 1).

[0003] This rotor includes, for example, a plurality of main pole permanent magnets magnetized in a direction perpendicular to the main surface of the rotor core (which serves as a back yoke) and arranged so that their magnetization direction alternates; a plurality of sub-pole permanent magnets magnetized in a direction different from that of the main pole permanent magnets and arranged so that their magnetization direction alternates, and arranged in the same direction as the main pole permanent magnets, alternating with the main pole permanent magnets; a magnetic body made of soft magnetic material between the sub-pole permanent magnets and adjacent sub-pole permanent magnets; and a non-magnetic layer, which is a non-magnetic region, arranged between the main pole permanent magnets and the adjacent main pole permanent magnets. Here, the sub-pole permanent magnets are longer than the non-magnetic layer, and both ends of the sub-pole permanent magnets are in contact with the main pole permanent magnets. The magnetic body has C-chamfered corners on the main pole permanent magnet side. This configuration allows magnetic flux to be concentrated along the d-axis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6947340 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a configuration in which the main pole permanent magnet and the sub pole permanent magnet are in contact with each other, the magnetic flux repels at the contact point, which poses a problem of reduced torque density. A configuration in which C-chamfering is applied to the two corners of the magnetic body facing the main pole permanent magnet is advantageous in that it allows for the creation of a gap below the magnetic body, thereby reducing the leakage flux caused by the backflow of magnetic flux that occurs at the corners of the magnetic body in a configuration without C-chamfering. However, creating a gap below the magnetic body poses the problem of significantly reducing torque density. This could result in inefficient energy utilization.

[0006] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a rotor for a rotating electrical machine that can improve torque density by effectively utilizing the magnetic flux of a permanent magnet, thereby contributing to energy efficiency. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. (1) A rotor (e.g., rotor 101 of the embodiment) of a rotating electric machine (e.g., rotating electric machine 100 of the embodiment) according to the present invention includes a rotor core (e.g., rotor core 5 of the embodiment), a permanent magnet (e.g., permanent magnet 6 of the embodiment) arranged on the circumferential surface of the rotor core, and a soft magnetic body (e.g., soft magnetic body 7 of the embodiment) provided at an end of the permanent magnet on the radially opposite side from the rotor core (e.g., outer end 9a of first magnet 9 of the embodiment) and having a saturation magnetic flux density greater than that of the permanent magnet, and the permanent magnet is located between the magnetic pole center of the rotor core and the rotation of the rotor core. The rotor core is characterized in that it comprises a d-axis oriented magnet (e.g., first magnet 9 in the embodiment) arranged on a d-axis passing through an axis (e.g., axis C in the embodiment) and oriented in the d-axis direction, and an obliquely oriented magnet (e.g., third magnet 11 in the embodiment) arranged adjacent to the d-axis oriented magnet in the circumferential direction and oriented in a direction oblique to the d-axis and the circumferential direction, the end of the d-axis oriented magnet opposite the rotor core is positioned closer to the rotor core than the end of the obliquely oriented magnet opposite the rotor core, and the soft magnetic material is provided at the end of the d-axis oriented magnet.

[0008] This configuration allows the magnetic flux of the permanent magnet to be concentrated on the soft magnetic material on the d-axis, improving the torque density of the rotor, which in turn contributes to energy efficiency.

[0009] (2) In the above configuration, the permanent magnet comprises a circumferentially oriented magnet (e.g., second magnet 10 in the embodiment) oriented in a circumferential direction perpendicular to the q-axis passing through the pole boundary between circumferentially adjacent magnetic poles and the rotation axis, and the circumferentially oriented magnet is arranged at a location overlapping with the q-axis, and the obliquely oriented magnet may be arranged between the d-axis oriented magnet and the circumferentially oriented magnet.

[0010] This configuration allows the orientation of the permanent magnets to change smoothly between the d-axis and the adjacent d-axis, which improves the torque density of the rotor compared to when the orientation of the permanent magnets changes suddenly.

[0011] (3) In the above configuration, the obliquely oriented magnet has a plurality of divided magnets (e.g., the first divided magnet 13 and the second divided magnet 14 in the embodiment) arranged in the circumferential direction, and the orientation of each divided magnet may gradually change to align with the d-axis as it approaches the d-axis.

[0012] This configuration allows the orientation of the permanent magnets to gradually change to align with the d-axis direction as they move from the q-axis toward the d-axis. Because the orientation of the permanent magnets changes smoothly, the torque density of the rotor can be improved compared to when the orientation of the permanent magnets changes suddenly.

[0013] (4) In the above configuration, a flux barrier (e.g., flux barrier 12 in the embodiment) that does not allow magnetic flux to pass easily may be provided between at least one of the permanent magnets and the rotor core at a location where the pole boundary between adjacent magnetic poles in the circumferential direction overlaps with the q-axis passing through the rotation axis.

[0014] By providing a flux barrier, such as an air gap or resin, the rotor can be made lighter. The magnetic flux on the rotor core side of the permanent magnets does not easily contribute to the torque of the rotor. By providing a flux barrier between the permanent magnets and the rotor core, the rotor can be made lighter while improving torque density.

[0015] (5) In the above configuration, the soft magnetic body may have a width in the circumferential direction of the rotor core that decreases toward the rotor core in the radial direction of the rotor core.

[0016] This configuration allows the magnetic flux of the permanent magnets to be further concentrated on the d-axis, which increases the magnetic flux density on the d-axis and improves the torque density of the rotor.

[0017] (6) In the above configuration, the side surface of the flux barrier facing the permanent magnet (for example, the peripheral surface 12a of the flux barrier 12 in the embodiment) may be formed in an uneven shape so as to be concave on the q axis.

[0018] This configuration ensures that the magnetic flux path between the obliquely oriented magnets arranged on both sides of the q-axis in the circumferential direction is on the rotor core side, allowing the magnetic flux of the obliquely oriented magnets to be utilized as effectively as possible.

[0019] (7) In the above configuration, the circumferential surface of the rotor core that contacts the permanent magnet (for example, the outer circumferential surface 5a of the rotor core 5 in the embodiment) may be made of a soft magnetic material (for example, the soft magnetic material 5b in the embodiment).

[0020] This configuration allows a magnetic path to be formed on the circumferential surface of the rotor core using soft magnetic material, thereby increasing the effective magnetic flux of the rotor and increasing the torque of the rotor.

[0021] (8) In the above configuration, the permanent magnet that is in contact with both the soft magnetic material and the flux barrier may have a constant thickness between the soft magnetic material and the flux barrier (for example, the thickness L1 between the soft magnetic material and the flux barrier in the fifth variant).

[0022] This configuration allows the width of the magnetic path of the permanent magnet itself to be kept constant between the soft magnetic material and the flux barrier. In other words, it is possible to prevent the width of the magnetic path of the permanent magnet itself from being locally narrowed between the soft magnetic material and the flux barrier. This improves the demagnetization resistance and torque density of the permanent magnet.

[0023] (9) In the above configuration, the flux barrier may include a gap formed by being surrounded by the rotor core and the permanent magnet, and an adhesive (e.g., adhesive 22 of the sixth variant) filled in the gap.

[0024] The permanent magnets on the q-axis have a weak magnetic attraction to the rotor core, so by using an adhesive, the adhesive strength of the permanent magnets on the q-axis to the rotor core can be increased.

[0025] (10) In the above configuration, the flux barrier may include a non-magnetic material (e.g., non-magnetic material 23 of the seventh variant) housed in the gap, and the adhesive may be filled between the gap and the non-magnetic material.

[0026] With this configuration, the rigidity of the entire permanent magnet can be increased by providing a non-magnetic material in the gap.

[0027] (11) In the above configuration, a ring member (for example, ring member 24 of the eighth modified example) may be provided to cover the peripheral surface of the permanent magnet on the side opposite to the rotor core, and the permanent magnet may be fixed by the ring member.

[0028] With this configuration, the centrifugal force acting on the permanent magnets can be received by the ring member, which increases the adhesive force of the permanent magnets to the rotor core and enables the rotor to rotate at high speeds. [Effects of the Invention]

[0029] According to the present invention, by effectively utilizing the magnetic flux of the permanent magnet, it is possible to improve torque density, which in turn contributes to energy efficiency. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view of a rotor of a rotating electrical machine according to an embodiment of the present invention; [Figure 2] Enlarged view of part II in Figure 1. [Figure 3] FIG. 10 is a diagram showing the configuration of a rotor according to a first modified example. [Figure 4] FIG. 10 is a diagram showing the configuration of a rotor according to a second modified example. [Figure 5] FIG. 10 is a diagram showing the configuration of a rotor according to a third modified example. [Figure 6]10A and 10B are diagrams showing rotors according to the present embodiment and a third modified example, in which (a) is a graph showing changes in magnetic flux density of a permanent magnet, and (b) is a diagram showing the configuration of the rotor. [Figure 7] FIG. 10 is a diagram showing the configuration of a rotor according to a fourth modified example. [Figure 8] FIG. 10 is a diagram showing the configuration of a rotor according to a fifth modified example. [Figure 9] FIG. 13 is a diagram showing the configuration of a rotor according to a sixth modified example. [Figure 10] FIG. 13 is a diagram showing the configuration of a rotor according to a seventh modified example. [Figure 11] FIG. 13 is a diagram showing the configuration of a rotor according to an eighth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0031] [Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0032] <Rotating electric machines> Fig. 1 is a cross-sectional view of a rotating electrical machine 100 according to this embodiment. Fig. 2 is an enlarged view of part II in Fig. 1. As shown in FIG. 1, a rotating electric machine 100 includes a cylindrical stator 103 and a rotor 101 that is rotatable relative to the stator 103. In the following description, the direction parallel to the rotation axis C of the rotor 101 (hereinafter simply referred to as axis C) will be referred to simply as the axial direction. The rotation direction of the rotor 101 will be referred to as the circumferential direction. The direction perpendicular to the axial direction and the circumferential direction will be referred to as the radial direction.

[0033] <Stator> The stator 103 includes a cylindrical stator core 1 and a coil 2 wound around the stator core 1 . The stator core 1 is formed, for example, by laminating multiple electromagnetic steel sheets. The stator core 1 has a cylindrical back yoke 25 and multiple teeth 3 that protrude radially inward from an inner peripheral surface 25a of the back yoke 25. The teeth 3 are arranged at equal intervals in the circumferential direction. Slots 4 are formed between each tooth 3. A coil 2 is inserted into each slot 4 and wound around each tooth 3.

[0034] <Rotor> The rotor 101 is disposed radially inside the stator 103. That is, the rotating electric machine 100 is a so-called inner rotor type rotating electric machine. The rotor 101 includes a shaft 102, a cylindrical rotor core 5 fixed to the outer peripheral surface of the shaft 102, and a permanent magnet 6 provided on the outer peripheral surface 5a of the rotor core 5. The central axis of the shaft 102 coincides with the axis C and rotates around this axis C.

[0035] A through-hole 8 that penetrates the rotor core 5 in the axial direction is formed in the radial center of the rotor core 5. A shaft 102 is inserted or press-fitted into this through-hole 8, thereby fixing the rotor core 5 to the outer peripheral surface of the shaft 102. A soft magnetic material 5b is provided on the outer peripheral surface 5a of the rotor core 5. The soft magnetic material 5b covers the entire outer peripheral surface 5a of the rotor core 5. A permanent magnet 6 is provided on the outer peripheral surface of the soft magnetic material 5b.

[0036] The permanent magnet 6 has a plurality of magnetic poles set in the circumferential direction, which is the same as the plurality of magnetic poles set on the outer peripheral surface 5a of the rotor core 5. The orientation of each magnetic pole alternates in the circumferential direction. In the following description, the line passing through the magnetic pole center of each magnetic pole and the axis C is defined as the d-axis. The line passing through the pole boundary between adjacent magnetic poles in the circumferential direction and the axis C is defined as the q-axis.

[0037] <Permanent magnet> 2, one magnetic pole of the permanent magnet 6 includes a first magnet 9 arranged on the d-axis, a second magnet 10 arranged on the q-axis, a third magnet 11 arranged between the first magnet 9 and the second magnet 10, and a soft magnetic body 7 arranged on the d-axis and radially outward of the first magnet 9. The permanent magnet 6 forms a flux barrier 12 between itself and the rotor core 5 at a location overlapping with the q-axis.

[0038] <First magnet> The first magnets 9 are oriented in the d-axis direction. More specifically, the north pole of the first magnets 9 is oriented radially outward. The south pole of the first magnets 9 is oriented radially inward. The arrows shown on the permanent magnets 6 in the figure indicate the orientation of the magnets. The first magnet 9 is integrally formed of a first magnet base portion 17 that is rectangular and long in the circumferential direction when viewed from the direction of the axis C, and a first magnet main body portion 18 that is trapezoidal and whose circumferential width decreases as it extends radially outward from the first magnet base portion 17. The radially outer end 9a of the first magnet 9 is located radially inward of the radially outer end 10a of the second magnet 10 and the radially outer end 11a of the third magnet 11. The circumferential side surface 18b of the first magnet body 18 is slightly curved so as to be convex toward the d-axis.

[0039] <Second magnet> The second magnet 10 is oriented in the circumferential direction perpendicular to the q axis. When viewed from the direction of the axis C, the second magnet 10 is integrally formed with a second magnet body portion 15 having a rectangular shape that is elongated in the radial direction, and a second magnet inner end portion 16 that is positioned radially inward of the second magnet body portion 15. The outer end portion 15a of the second magnet body portion 15 is curved along a circle centered on the axis C. The second magnet inner end portion 16 is triangular when viewed from the direction of the axis C, tapering radially inward. The tip of the second magnet inner end portion 16 is located on the q axis.

[0040] <Third magnet> The third magnet 11 is oriented in a direction inclined with respect to the d-axis and the circumferential direction. The q-axis side surface 11b of the third magnet 11 in the circumferential direction is in contact with the side surface 10b of the second magnet 10. The q-axis side surface 11b of the third magnet 11 is formed to fit along the side surface 10b of the second magnet 10. The d-axis side surface 11c of the third magnet 11 in the circumferential direction is in contact with the side surface 18b of the first magnet main body portion 18. The d-axis side surface 11c of the third magnet 11 is formed to fit along the side surface 18b of the first magnet main body portion 18. The radially inner inner surface 11d of the third magnet is located on a plane that passes through the radially inner corner 18a of the first magnet main body portion 18 and the radially inner corner 15b of the second magnet main body portion 15.

[0041] The outer end 11a of the third magnet 11 is curved along a circle centered on the axis C. The outer end 11a of the third magnet 11 is located on the same circle as the outer end 15a of the second magnet main body 15. The third magnet 11 is divided into two parts in the circumferential direction of the third magnet 11. That is, the third magnet 11 includes a first divided magnet 13 located on the second magnet 10 side and a second divided magnet 14 located on the first magnet 9 side.

[0042] <First divided magnet and second divided magnet> The first divided surface 19 between the first divided magnet 13 and the second divided magnet 14 is located in the center between the side surface 18b of the first magnet main body 18 and the side surface 10b of the second magnet 10. Of the d-axis side surface 11c of the second divided magnet 14 on the first magnet 9 side, a portion of the radially outer side is located radially outward of the outer end 9a of the first magnet 9 (hereinafter, this portion of the d-axis side surface 11c will be referred to as the outer side surface 14a). The outer side surface 14a is formed with an inclination that moves away from the d-axis as it extends radially outward.

[0043] The magnetization directions of the first and second magnet segments 13 and 14 gradually change to align with the d-axis as they move from the q-axis toward the d-axis. At this time, the inclination of the magnetization direction of the first magnet segment 13 relative to the d-axis is greater than the inclination of the magnetization direction of the second magnet segment 14 relative to the d-axis. The first magnet 9, second magnet 10, and third magnet 11 are formed in line symmetry about the d-axis and line symmetry about the q-axis when viewed from the direction of axis C. That is, a recess 26 is formed on the outer peripheral surface of the permanent magnet 6 by the outer end 9a of the first magnet 9 and the outer side surfaces 14a of the second divided magnets 14 arranged on both circumferential sides of the first magnet 9. A soft magnetic body 7 is provided in this recess 26.

[0044] <Soft magnetic material> The soft magnetic body 7 has a trapezoidal shape whose circumferential width decreases radially inward when viewed from the direction of the axis C. The circumferential width of the bottom surface 7a of the soft magnetic body 7 that contacts the first magnet 9 is the same as the circumferential width of the outer end 9a of the first magnet 9. The circumferential side surface 7b of the soft magnetic body 7 contacts the outer side surface 14a of the second divided magnet 14. The outer end 7c on the radially outer side of the soft magnetic body 7 is curved to follow a circle centered on the axis C. The outer end 7c is located on the same circle as the outer end 15a of the second magnet main body 15 and the outer end 11a of the third magnet 11. The saturation magnetic flux density of the soft magnetic body 7 is greater than that of the first magnet 9.

[0045] <Flux Barrier> Multiple flux barriers 12 are formed in the circumferential direction of rotor core 5. Each flux barrier 12 is a gap surrounded by the soft magnetic material 5b of rotor core 5, the side surface 17a of first magnet base portion 17, the inner surface 11d of third magnet 11, and the inner surface 16a of second magnet inner end portion 16. Therefore, due to the shape of second magnet inner end portion 16, flux barrier 12 has a radially outer peripheral surface 12a formed with an uneven shape so as to be concave on the q axis. In other words, ridge line 12b of this peripheral surface 12a is aligned with the tip of second magnet inner end portion 16. Therefore, ridge line 12b of peripheral surface 12a is located on the q axis.

[0046] <Actions and Effects> Next, the operation and effects of the rotor 101 of the rotating electrical machine 100 according to this embodiment will be described. In a rotating electric machine 100 including a rotor 101 according to this embodiment, when power is supplied to the coil 2, a flux linkage is formed in the stator core 1 around which the coil 2 is wound. Magnetic attractive and repulsive forces are generated between the flux linkage and the permanent magnets 6, causing the rotor 101 to rotate continuously.

[0047] Because the orientation of the permanent magnets 6 changes smoothly from the q axis to the d axis, the surface magnetic flux density of the rotor 101 can be more easily concentrated on the d axis compared to when the orientation of the permanent magnets 6 changes abruptly. As a result, the torque density of the rotor 101 can be improved. Furthermore, the soft magnetic body 7 is provided on the outer end 9a of the first magnet 9. The saturation magnetic flux density of the soft magnetic body 7 is greater than that of the first magnet 9. Therefore, the surface magnetic flux density on the d axis can be increased compared to when the soft magnetic body 7 is not provided. As a result, the magnetic flux of the permanent magnets 6 can be further concentrated on the d axis. Therefore, the torque density of the rotor 101 can be improved, which in turn contributes to energy efficiency.

[0048] The third magnet 11 is divided in the circumferential direction and is composed of a first divided magnet 13 and a second divided magnet 14. This allows for smoother changes in orientation within the third magnet 11. This further improves the torque density of the rotor 101.

[0049] The circumferential width of the soft magnetic body 7 decreases as it moves radially inward. That is, the circumferential side surface 7b of the soft magnetic body 7 (the outer side surface 14a of the second divided magnet 14) is inclined so as to move away from the d-axis as it moves radially outward. This makes it easier to concentrate the direction of the magnetic flux flowing into the soft magnetic body 7 on the d-axis. This further improves the torque density of the rotor 101.

[0050] By making the flux barrier 12 an air gap, it is possible to reduce the weight of the rotor 101. The magnetic flux of the permanent magnet 6 on the rotor core 5 side is unlikely to contribute to the torque of the rotor 101. By providing the flux barrier 12 at a position where it has little effect on the torque, it is possible to reduce the weight of the rotor 101 while improving the torque density. The flux barrier 12 has a radially outer peripheral surface 12a that is concave on the q axis. This shape is due to the configuration of the second magnet inner end portion 16, and it ensures a magnetic path. That is, in the third magnets 11 located on both sides of the first magnet 9 in the circumferential direction, the magnetic flux that flows between them from the radially inner side can pass through the second magnet inner end portion 16. This allows the magnetic flux of the third magnets located on both sides in the circumferential direction to be utilized as effectively as possible.

[0051] A soft magnetic material 5b is provided on the outer peripheral surface 5a of the rotor core 5. With this configuration, a magnetic path can be formed on the outer peripheral surface 5a of the rotor core 5. This allows the effective magnetic flux of the rotor 101 to be further increased, and the torque of the rotor 101 to be increased.

[0052] Next, first to eighth modified examples of the above-described embodiment will be described. In the first to eighth modified examples, the same components as those in the above-described embodiment will be assigned the same reference numerals, and their description will be omitted. In the first to eighth modified examples, only the differences will be described.

[0053] [First Modification] First, a first modified example will be described with reference to Fig. 3. Fig. 3 is a diagram showing the configuration of a rotor 101 according to the first modified example. Fig. 3 corresponds to Fig. 2 described above (the same applies to the following modified examples). The difference between the above-described embodiment and the first modified example is that the configuration and shape of the permanent magnet 6 in the embodiment are different from those in the first modified example. 3, the first magnet 9 has a rectangular shape that is long in the radial direction when viewed from the direction of the axis C. Therefore, the side surface 17a of the first magnet base portion 17 is integral with the side surface 18b of the first magnet main body portion 18 and is located on the same plane (hereinafter, the side surface 17a and the side surface 18b are collectively referred to as the circumferential side surface 9b of the first magnet 9). The side surface 9b of the first magnet 9 is aligned in the radial direction.

[0054] The second magnet 10 has a rectangular shape that is slightly elongated in the radial direction when viewed from the direction of the axis C. The second magnet 10 is formed by a second magnet body portion 15. The third magnet 11 is composed of a single permanent magnet. The d-axis side inner surface 11e of the third magnet 11 is in contact with the soft magnetic material 5b. The q-axis side inner surface 11f of the third magnet 11 is curved so as to be convex radially outward. One end of the q-axis side inner surface 11f of the third magnet 11 is in contact with the soft magnetic material 5b, and the other end is in contact with the corner 15b of the second magnet main body 15. The magnetization direction of the third magnet 11 is oriented in a direction inclined with respect to the d-axis and the circumferential direction so as to point from the magnetization direction of the first magnet 9 toward the magnetization direction of the second magnet 10.

[0055] Even with this configuration, the orientation of the permanent magnets 6 can be gradually changed to align with the q-axis direction as it moves from the q-axis toward the d-axis, thereby achieving the same effects as the above-described embodiment.

[0056] The flux barrier 12 is a gap surrounded by the outer peripheral surface of the soft magnetic material 5b, the inner surface 11f of the third magnet 11 on the q-axis side, and the inner surface 15c of the second magnet main body portion 15. Even with this configuration, the same effects as those of the above-described embodiment can be achieved.

[0057] [Second Modification] Next, a second modification of the above-described embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram showing the configuration of a rotor 101 according to the second modification. The difference between the first and second modified examples described above is that while there is one third magnet 11 in the first modified example, the third magnet 11 in the second modified example is made up of three magnets 13, 14, and 20.

[0058] 4, the third magnet 11 of the second modified example is divided into three parts in the circumferential direction. The third magnet 11 includes a first divided magnet 13 arranged on the second magnet 10 side, a second divided magnet 14 arranged on the first magnet 9 side of the first divided magnet 13, and a third divided magnet 20 arranged between the second divided magnet 14 and the first magnet 9.

[0059] The first division surface 19 between the first divided magnet 13 and the second divided magnet 14 is located closer to the second magnet 10 than the second division surface 21 between the second divided magnet 14 and the third divided magnet 20. The first division surface 19 and the second division surface 21 are aligned in the radial direction.

[0060] A portion of the q-axis side inner surface 11f of the third magnet 11 is the inner side surface 20a of the third magnet segment 20. For this reason, the q-axis side inner surface 11f of the third magnet 11 extends radially outward from the soft magnetic material 5b and is curved so as to be convex radially outward from above the inner side surface 20a of the third magnet segment 20 toward the corner 15b of the second magnet main body portion 15. The magnetization directions of the first divided magnet 13, the second divided magnet 14, and the third divided magnet 20 gradually change to align with the d-axis as they move from the q-axis to the d-axis. The inclination of the magnetization direction of the first divided magnet 13 with respect to the d-axis is greater than the inclination of the magnetization direction of the second divided magnet 14 with respect to the d-axis. The inclination of the magnetization direction of the second divided magnet 14 with respect to the d-axis is greater than the inclination of the magnetization direction of the third divided magnet 20 with respect to the d-axis.

[0061] Even with this configuration, the orientation of the permanent magnets 6 can be gradually changed to align with the q-axis direction as it moves from the q-axis toward the d-axis. Furthermore, the orientation of the permanent magnets 6 can be changed more smoothly than in the previous embodiment. This allows for a higher torque density than in the previous embodiment.

[0062] [Third Modification] Next, a third modified example will be described with reference to Figures 5 and 6. Figure 5 is a diagram showing the configuration of a rotor 101 according to the third modified example. The difference between the above-described embodiment and the third modified example is that the shapes of the soft magnetic body 7 and the first magnet 9 in the above-described embodiment are different from those of the soft magnetic body 7 and the first magnet 9 in the third modified example.

[0063] Specifically, as shown in FIG. 5, the soft magnetic body 7 of the third modified example is formed in a triangular shape when viewed from the direction of the axis C so that its circumferential width tapers radially inward. The width of the bottom surface 7a of the soft magnetic body 7 is extremely small. Accordingly, the circumferential width of the outer end portion 9a of the first magnet 9 that contacts the bottom surface 7a of the soft magnetic body 7 also becomes small. In other words, the first magnet main body portion 18 is formed so as to taper radially outward, and is formed in a triangular shape when viewed from the direction of the axis C. The side surface 18b of the first magnet main body portion 18 is convex toward the d axis and is more curved than in the above-described embodiment.

[0064] Here, a change in magnetic flux density caused by the permanent magnet 6 due to the difference between the shape of the soft magnetic body 7 in the above embodiment and the shape of the soft magnetic body 7 in the third modified example will be described. 6 shows the configuration of the rotor 101 according to this embodiment and the third modified example, where (a) is a graph showing the change in magnetic flux density of the permanent magnet 6 when the vertical axis represents the magnetic flux density of the permanent magnet 6 and the horizontal axis represents the rotation angle of the rotor 101, and (b) is a diagram showing the configuration of the rotor. For convenience of explanation, (b) shows the configuration of the rotor 101 in a linear manner. (a) corresponds to the shape of (b). In FIG. 6, the solid line indicates the magnetic flux density waveform W1 according to the third modified example, and the two-dot chain line indicates the magnetic flux density waveform W2 according to this embodiment.

[0065] Both the magnetic flux density waveform W1 and the magnetic flux density waveform W2 have a maximum value on the d-axis. However, the magnetic flux density waveform W1 is flat near the d-axis. On the other hand, the magnetic flux density waveform W2 has a peak on the d-axis. The configurations according to the above-described embodiment and the third modified example include a soft magnetic body 7. The circumferential side surface 7b of the soft magnetic body 7 is inclined so as to move away from the d-axis as it extends radially outward. Of these, in the third modified example, the circumferential width of the bottom surface 7a of the soft magnetic body 7 is smaller than in the above-described embodiment. Furthermore, the inclination of the side surface 7b of the soft magnetic body 7 with respect to the d-axis is greater than in the above-described embodiment.

[0066] Therefore, by adopting the configuration according to the third modification, the direction of the magnetic flux flowing into the soft magnetic body 7 can be more easily concentrated on the d-axis than in the above-described embodiment, and the magnetic flux density can be increased. Therefore, the torque density of the rotor 101 can be further improved compared to the above-described embodiment.

[0067] [Fourth Modification] Next, a fourth modified example will be described with reference to Fig. 7. Fig. 7 is a diagram showing the configuration of a rotor 101 according to the fourth modified example. The difference between the above-mentioned embodiment and the fourth variant is that the shapes of the second magnet 10, the third magnet 11 and the flux barrier 12 in the above-mentioned embodiment are different from the shapes of the second magnet 10, the third magnet 11 and the flux barrier 12 in the fourth variant.

[0068] Specifically, as shown in FIG. 7, the second magnet 10 of the fourth modified example is made up of a second magnet main body portion 15. The inner surface 11d of the third magnet 11 is composed of a plane passing through the corner 18a of the first magnet main body 18 and the radially inner end 19a of the first divided surface 19 (hereinafter referred to as the inner surface 14b of the second divided magnet 14), and a plane passing through the radially inner end 19a of the first divided surface 19 and the corner 15b of the second magnet main body 15 (hereinafter referred to as the inner surface 13a of the first divided magnet 13). The inner surface 13a of the first divided magnet 13 is aligned with the outer peripheral surface 5a of the rotor core 5.

[0069] A radially inner end 19a of the first divided surface 19 is located radially outward of a plane passing through a corner 18a of the first magnet body portion 18 and a corner 15b of the second magnet body portion 15. The flux barrier 12 is a gap surrounded by the outer surface of the soft magnetic material 5b of the rotor core 5, the side surface 17a of the first magnet base portion 17, the inner surface 11d of the third magnet 11, and the inner surface 15c of the second magnet main body portion 15. Even with this configuration, the same effects as those of the above-described embodiment can be achieved.

[0070] [Fifth Modification] Next, a fifth modified example will be described with reference to Fig. 8. Fig. 8 is a diagram showing the configuration of a rotor 101 according to the fifth modified example. The fifth modified example differs from the above-described embodiment in that the shapes of the permanent magnets 6 and soft magnetic bodies 7 in the above-described embodiment are different from the shapes of the permanent magnets 6 and soft magnetic bodies 7 in the fifth modified example. In the fifth modification, the thickness L1 of the permanent magnet 6 at the portion located between the soft magnetic material 7 and the flux barrier 12 (hereinafter referred to as the thickness between the soft magnetic material and the flux barrier) is constant.

[0071] The thickness L1 between the soft magnetic material and the flux barrier is defined as the thickness of the permanent magnet 6 located between the side surface 7b of the soft magnetic material 7 and the inner surface 11d of the third magnet 11. In this case, the inclination angles of the side surface 7b of the soft magnetic material 7 and the inner surface 11d of the third magnet 11 with respect to the d-axis are formed to be equal so that the thickness L1 between the soft magnetic material and the flux barrier is constant. This configuration allows the permanent magnet 6, whose soft magnetic material-flux barrier thickness L1 is constant, to maintain a constant width of the magnetic path. In other words, it is possible to prevent the width of the magnetic path of the permanent magnet 6 itself from being locally narrowed between the soft magnetic material 7 and the flux barrier 12. This improves the demagnetization resistance of the permanent magnet 6 and the torque density of the rotor 101.

[0072] [Sixth Modification] Next, a sixth modified example will be described with reference to Fig. 9. Fig. 9 is a diagram showing the configuration of a rotor 101 according to the sixth modified example. The difference between the above-described embodiment and the sixth modification is that the configuration of the flux barrier 12 in the embodiment is different from the configuration of the flux barrier 12 in the sixth modification. Specifically, as shown in FIG. 9, the gap that was provided as the flux barrier 12 is filled with adhesive 22.

[0073] The outer peripheral surface of the soft magnetic material 5b of the rotor core 5, the side surface 17a of the first magnet base portion 17, the inner surface 16a of the second magnet inner end portion 16, and the inner surface 11d of the third magnet 11 are bonded together via the adhesive 22. As a result, the second magnet 10 and the third magnet 11, which were provided separately from the rotor core 5, are fixed to the rotor core 5 via the adhesive 22. The magnetization direction of the permanent magnets 6 on the q axis has a weak magnetic attraction force to the rotor core 5. Therefore, by using adhesive 22, the adhesive force of the permanent magnets 6 on the q axis to the rotor core 5 can be increased.

[0074] [Seventh Modification] Next, a seventh modified example will be described with reference to Fig. 10. Fig. 10 is a diagram showing the configuration of a rotor 101 according to the seventh modified example. The difference between the sixth and seventh modified examples is that the configuration and shape of the flux barrier 12 in the sixth modified example differs from the configuration and shape of the flux barrier 12 in the seventh modified example. Specifically, as shown in Fig. 10, the gap that was provided as the flux barrier 12 is filled with adhesive 22. Furthermore, a non-magnetic material 23 is embedded in the adhesive 22. The non-magnetic material 23 is, for example, a resin. However, this is not a limitation, and the non-magnetic material 23 may be any material as long as it is not magnetic. The shape of the flux barrier 12 is the same as that of the fourth modified example (Fig. 7) described above.

[0075] Compared to the sixth modification, the flux barrier 12 further includes a non-magnetic material 23 . The non-magnetic body 23 is formed in a shape that follows the peripheral surface 12a of the flux barrier 12. In other words, the non-magnetic body 23 is similar in shape to the flux barrier 12 and is reduced in size so that it can be inserted into the gap in the flux barrier 12. With this configuration, in addition to achieving the same effects as the sixth modified example described above, the rigidity of the permanent magnet 6 can be increased.

[0076] [Eighth Modification] Next, an eighth modified example will be described with reference to Fig. 11. Fig. 11 is a diagram showing the configuration of a rotor 101 according to the eighth modified example. The difference between the above-described embodiment and the eighth modified example is that the configuration of the rotor 101 in the above-described embodiment is different from the configuration of the rotor 101 in the eighth modified example. Specifically, as shown in FIG. 11, a rotor 101 of the eighth modified example has a ring member 24 on the radially outer side of the permanent magnets 6 and the soft magnetic bodies 7.

[0077] The ring member 24 is formed in a cylindrical shape centered on the axis C. The inner diameter of the ring member 24 is equal to the outer diameter of the rotor 101. The inner peripheral surface 24a of the ring member 24 contacts the outer peripheral surface of the rotor 101 formed by the outer ends of the permanent magnets 6 (the outer ends 10a of the second magnets 10 and the outer ends 11a of the third magnets 11) and the outer end 7c of the soft magnetic body 7. The ring member 24 is formed of a non-magnetic material, such as CFRP (carbon fiber reinforced plastic) or SUS (stainless steel).

[0078] The ring member 24 can press and fix the permanent magnets 6 and soft magnetic bodies 7 of the rotor 101 from the radially outer side. Therefore, the centrifugal force acting on the permanent magnets 6 due to the rotation of the rotor 101 can be received by the ring member 24. This increases the adhesive force of the permanent magnets 6 to the rotor core 5, enabling the rotor 101 to rotate at high speeds.

[0079] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment and modified example, the third magnet 11 is described as being divided into at most three pieces. However, this is not limited to this, and the third magnet 11 may be composed of four or more permanent magnets with different orientations. In this case, the orientation of each of the multiple permanent magnets constituting the third magnet may gradually change to align with the d-axis as it moves from the q-axis toward the d-axis.

[0080] In the above-described embodiment and modified examples, the case where the second magnet is provided on the permanent magnet 6 has been described. However, this is not limited to this, and the permanent magnet 6 does not have to be provided with the second magnet 10. In this case, a part of the third magnet 11 is provided in the portion where the second magnet 10 was disposed. Therefore, the third magnets 11 are arranged side by side on both sides in the circumferential direction around the q axis. Even in this configuration, the same effects as those of the above-described embodiment and modified examples can be achieved.

[0081] In the above-described embodiment and modified examples, the permanent magnet 6 is provided with the flux barrier 12. However, the present invention is not limited to this, and the permanent magnet 6 does not necessarily need to be provided with the flux barrier 12. Here, we show the calculation results of torque density for the first modified example in which the third magnet 11 is composed of one permanent magnet and the second modified example in which the third magnet 11 is composed of three permanent magnets, with and without the soft magnetic body 7 and the flux barrier 12. The shape of the soft magnetic body 7 is the same in both cases. The flux barrier 12 is formed by an air gap.

[0082] In the following, a case where the rotor 101 does not include the soft magnetic material 7 and the flux barrier 12 will be referred to as Case 1. A case where the rotor 101 includes the soft magnetic material 7 but does not include the flux barrier 12 will be referred to as Case 2. A case where the rotor 101 includes both the soft magnetic material 7 and the flux barrier 12 will be referred to as Case 3.

[0083] In the first modified example, it was confirmed that the torque densities in Cases 2 and 3 increased by 1.29% and 3.83%, respectively, relative to Case 1. In the second modified example, it was confirmed that the torque densities in Cases 2 and 3 increased by 1.26% and 3.93%, respectively, relative to Case 1.

[0084] If the flux barrier 12 is not provided, a magnetic path through which magnetic flux passes is formed inside the permanent magnet 6, making it possible to increase the torque. However, the weight increases due to the permanent magnet 6. If the flux barrier 12 is provided, the magnetic path inside the permanent magnet 6 is reduced, making the torque smaller. However, it is possible to reduce the weight of the rotor 101.

[0085] The flux barrier 12 is located on the q-axis, where the effect on torque is small, and on the rotor core 5 side of the permanent magnet 6. Therefore, it was confirmed that the weight could be reduced without significantly reducing torque, and as a result, the torque density could be improved. Therefore, when a reduction in the weight of the rotating electrical machine 100 is required, providing the flux barrier 12 is advantageous in that the torque density can be increased.

[0086] In the above-described embodiment and modified examples, the rotating electric machine 100 has been described as a so-called inner rotor type rotating electric machine in which the rotor 101 is disposed radially inside the stator 103. However, this is not limited to this, and the configurations of the above-described embodiment and modified examples can be adopted even if the rotating electric machine 100 is a so-called outer rotor type rotating electric machine in which the rotor 101 is disposed radially outside the stator 103.

[0087] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, as long as this does not deviate from the spirit of the present invention. [Explanation of symbols]

[0088] 5...Rotor core 5a...Outer surface (peripheral surface) 5b…Soft magnetic material 6...Permanent magnet 7...Soft magnetic material 9...First magnet (d-axis oriented magnet) 9a...Outer end (end of d-axis oriented magnet opposite to the rotor core) 10...Second magnet (circumferentially oriented magnet) 11...Third magnet (diagonally oriented magnet) 11a...Outer end (end of the obliquely oriented magnet opposite the rotor core) 12...Flux Barrier 12a…Surface (side) 13...First divided magnet (divided magnet) 14...Second divided magnet (divided magnet) 22...Adhesive 23…Nonmagnetic material 24...Ring member 100...Rotating electric machine 101...Rotor C...Axis (rotation axis) L1: Thickness between soft magnetic material and flux barrier (thickness)

Claims

1. A rotor core; a permanent magnet disposed on the circumferential surface of the rotor core; a soft magnetic body provided at an end of the permanent magnet opposite to the rotor core in the radial direction, the soft magnetic body having a saturation magnetic flux density greater than that of the permanent magnet; Equipped with The permanent magnet is a d-axis oriented magnet arranged on a d-axis passing through a magnetic pole center of the rotor core and a rotation axis of the rotor core, and oriented in the d-axis direction; an obliquely oriented magnet arranged adjacent to the d-axis oriented magnet in the circumferential direction and oriented in a direction oblique to the d-axis and the circumferential direction; Equipped with the position of the end of the d-axis oriented magnet opposite to the rotor core is located closer to the rotor core than the position of the end of the obliquely oriented magnet opposite to the rotor core, The soft magnetic material is provided at the end of the d-axis oriented magnet, a flux barrier that does not easily allow magnetic flux to pass between at least one of the permanent magnets and the rotor core at a location where a pole boundary between adjacent magnetic poles in the circumferential direction overlaps with a q-axis passing through the rotation axis; a side surface of the flux barrier facing the permanent magnet is formed in an uneven shape so as to be concave on the q axis; A rotor for a rotating electric machine.

2. A rotor core; a permanent magnet disposed on the circumferential surface of the rotor core; a soft magnetic body provided at an end of the permanent magnet opposite to the rotor core in the radial direction, the soft magnetic body having a saturation magnetic flux density greater than that of the permanent magnet; Equipped with The permanent magnet is a d-axis oriented magnet arranged on a d-axis passing through a magnetic pole center of the rotor core and a rotation axis of the rotor core, and oriented in the d-axis direction; an obliquely oriented magnet arranged adjacent to the d-axis oriented magnet in the circumferential direction and oriented in a direction oblique to the d-axis and the circumferential direction; Equipped with the position of the end of the d-axis oriented magnet opposite to the rotor core is located closer to the rotor core than the position of the end of the obliquely oriented magnet opposite to the rotor core, The soft magnetic material is provided at the end of the d-axis oriented magnet, a flux barrier that does not easily allow magnetic flux to pass between at least one of the permanent magnets and the rotor core at a location where a pole boundary between adjacent magnetic poles in the circumferential direction overlaps with a q-axis passing through the rotation axis; the permanent magnet in contact with both the soft magnetic material and the flux barrier has a constant thickness between the soft magnetic material and the flux barrier; A rotor for a rotating electric machine.

3. The permanent magnets include circumferentially oriented magnets that are oriented in the circumferential direction so as to be perpendicular to a q-axis that passes through a pole boundary between adjacent magnetic poles in the circumferential direction and the rotation axis, The circumferentially oriented magnet is disposed at a location overlapping with the q-axis, The obliquely oriented magnet is disposed between the d-axis oriented magnet and the circumferentially oriented magnet.

3. The rotor for a rotating electrical machine according to claim 1 or 2.

4. The obliquely oriented magnet has a plurality of divided magnets arranged in a circumferential direction, The orientation of each of the divided magnets gradually changes to be aligned with the d-axis as it approaches the d-axis.

3. The rotor for a rotating electrical machine according to claim 1 or 2.

5. the soft magnetic body has a circumferential width that decreases toward the rotor core in the radial direction of the rotor core; 3. The rotor for a rotating electrical machine according to claim 1 or 2.

6. The peripheral surface of the rotor core that contacts the permanent magnet is made of a soft magnetic material.

3. The rotor for a rotating electrical machine according to claim 1 or 2.

7. The flux barrier includes a gap formed by being surrounded by the rotor core and the permanent magnet, and an adhesive filled in the gap.

3. The rotor for a rotating electrical machine according to claim 1 or 2.

8. the flux barrier includes a non-magnetic material housed in the gap; The adhesive is filled between the gap and the non-magnetic material.

8. The rotor for a rotating electrical machine according to claim 7.

9. a ring member covering a peripheral surface of the permanent magnet opposite to the rotor core, and the permanent magnet being fixed by the ring member; 3. The rotor for a rotating electrical machine according to claim 1 or 2.

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