Rotating electric machine

Abstract

To provide a rotary electric machine capable of enhancing the mechanical strength of a rotor while suppressing leakage of magnetic flux.SOLUTION: A rotary electric machine includes a stator and a rotor 11. A magnetic pole 18 of the rotor includes a magnet hole 19, a permanent magnet 13A, a first gap part 21, a second gap part 22, and a rib 23. The magnet hole extends circumferentially across a magnet pole center line along a radial direction of the rotor, and is formed in an almost arc shape in an axial view so that both ends in an extension direction are close to an outer circumferential edge of the rotor. The permanent magnet is inserted and disposed in the magnet hole. The first gap part is formed between both ends of the magnet hole in the extension direction and the permanent magnet. The second gap part extends to be separated from the magnet hole on an extension of both ends of the magnet hole in the extension direction. The rib is disposed between the first gap part and the second gap part, and connects an outer region and an inner region of the first gap part and the second gap part in the radial direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine in which a rotor is rotatably disposed inside the radial direction of an annular stator.

Background Art

[0002] As a rotating electrical machine, there is known one in which a rotor is rotatably disposed inside the radial direction of an annular stator, and a plurality of permanent magnets are provided inside the rotor (see, for example, Patent Document 1).

[0003] In the rotating electrical machine described in Patent Document 1, a plurality of magnetic poles are provided inside the rotor with a circumferential spacing. Each magnetic pole is provided symmetrically on the left and right with respect to a magnetic pole center line (d-axis line) along which a substantially arc-shaped (cuneiform-shaped) magnet hole extends in the radial direction, and a permanent magnet is inserted and disposed in each magnet hole. The left and right magnet holes are formed so as to form a substantially U-shaped as a whole and open to the outside in the radial direction.

[0004] The permanent magnet accommodated and disposed in each magnet hole generates a magnetic torque (attraction / repulsion force) with the magnetic pole due to the winding current on the stator side. Further, the region where there is no permanent magnet in each magnet hole functions as a flux barrier for regulating the flow of magnetic flux. The vicinity of the outer peripheral edge of the rotor close to the outer ends of the pair of magnet holes having a substantially U-shaped functions as a salient pole on the rotor side and serves as a passage for the flow of the rotating magnetic flux of the stator. The rotor rotates under the action of the magnetic torque of the permanent magnet and the reluctance torque.

[0005] In addition, a center rib is disposed along the magnetic pole center line between the end portions on the magnetic pole center line side of the pair of magnet holes. The center rib connects the outer region and the inner region in the radial direction of the magnet hole divided by the magnet hole, and maintains the mechanical strength of the outer peripheral edge portion of the rotor. Since a large centrifugal force acts on the outer peripheral edge portion of the rotor during rotation of the rotor, the center rib suppresses deformation of the outer peripheral edge portion of the rotor due to this centrifugal force.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-137139 [Overview of the project] [Problems that the invention aims to solve]

[0007] The rotating electric machine described in Patent Document 1 has a center rib positioned between the left and right magnet holes, which allows for high mechanical strength of the rotor. However, because the center rib is positioned near the magnetic pole centerline (d-axis) where the flow of magnet flux and stator rotational flux is concentrated, the center rib becomes a short-circuit path for the magnet flux and rotational flux, increasing leakage flux. As a result, the above rotating electric machine cannot efficiently utilize the magnetic force of the magnets, leading to the need for larger permanent magnets.

[0008] Therefore, the present invention aims to provide a rotating electric machine that can increase the mechanical strength of the rotor while suppressing magnetic flux leakage. This invention also contributes to the miniaturization and weight reduction of the permanent magnets used, thereby improving energy efficiency. [Means for solving the problem]

[0009] A rotating electric machine according to one aspect of the present invention comprises an annular stator (for example, stator 10 in the embodiment) and a rotor (for example, rotor 11 in the embodiment) rotatably disposed radially inward of the stator and having a plurality of magnetic poles (for example, magnetic poles 18 in the embodiment) spaced apart in the circumferential direction, wherein the magnetic poles of the rotor extend circumferentially across a magnetic pole centerline (for example, magnetic pole centerline op in the embodiment) along the radial direction of the rotor, and both ends in the extending direction are close to the outer edge of the rotor. A magnet hole (for example, magnet hole 19 in the embodiment) formed in a substantially arc shape when viewed in the axial direction so as to be in contact with the magnet hole; a permanent magnet (for example, permanent magnet 13A in the embodiment) inserted and positioned in the magnet hole; a first void (for example, first void 21 in the embodiment) formed between the ends of the magnet hole in the extending direction and the permanent magnet; a second void (for example, second void 22 in the embodiment) extending away from the magnet hole on the extension of the ends of the magnet hole in the extending direction; and between the first void and the second void The first and second air gaps are provided with a rib (for example, rib 23 in the embodiment) that is arranged to connect the radial outer region and the inner region of the first and second air gaps, wherein the opening angle between the normal passing through the outer end of the permanent magnet on the side away from the magnetic pole centerline (for example, normal nm in the embodiment) and the magnetic pole centerline is θMag, and the opening angle between the normal passing through the outer end of the first air gap on the side away from the magnetic pole centerline (for example, normal nr in the embodiment) and the magnetic pole centerline is θRib, and the second air gap The opening angle θRib is set such that it satisfies the following equations (1) and (2), where θ1 is the opening angle between the magnetic pole centerline and the normal passing through the outer end on the side away from the magnetic pole centerline (for example, the normal ns in the embodiment), and θ2 is the opening angle between the magnetic pole centerline and the magnetic pole centerline and the normal passing through the intermediate position between the outer end of the permanent magnet on the side away from the magnetic pole centerline and the outer end of the second gap on the side away from the magnetic pole centerline. θ2 = (θ1 + θMag) / 2 …(1) θRib < θ² …(2)

[0010] In the above configuration, the magnets are arranged so as to straddle the magnetic pole centerline, and ribs connecting the radial outer and inner regions of the air gaps (first and second air gaps) are positioned on one end and the other end in the extending direction of the magnet hole. Therefore, magnetic flux leakage due to the wrapping of magnetic flux and rotational flux is less likely to occur in the vicinity of the magnetic pole centerline where the magnetic flux of the magnets and the rotational magnetic flux of the stator tend to concentrate. In addition, when a tensile load is applied in a direction substantially aligned with the magnetic pole centerline, tension acts on the ribs on both sides in the extending direction of the magnet hole, suppressing deformation of the outer edge of the rotor. In particular, since the ribs are formed such that the opening angle θRib satisfies equations (1) and (2) above, bending stress is less likely to occur in the ribs when a tensile load is applied in a direction substantially aligned with the magnetic pole centerline. Therefore, the mechanical strength of the rotor can be maintained at a high level.

[0011] The first void may be provided with a first flange portion (for example, the first flange portion 24 in the embodiment) at the end facing the rib, which is thicker than the permanent magnet, and the second void may be provided with a second flange portion (for example, the second flange portion 25 in the embodiment) at the end facing the rib, which is thicker than the permanent magnet.

[0012] In this case, the length of the ribs can be increased by using the first and second flanges, which are thicker than the permanent magnets. This increases the magnetic path resistance of the magnetic flux trying to flow through the ribs, making it possible to further suppress the leakage of magnetic flux and rotating flux through the ribs. Therefore, by adopting this configuration, it becomes possible to utilize the magnetic force of the permanent magnets more effectively and to further miniaturize and lighten the permanent magnets.

[0013] It is desirable that the first flange portion and the second flange portion have substantially the same extension length radially inward of the rotor.

[0014] If one of the first and second flanges extends radially inward longer than the other, the flange with the longer extension is more likely to obstruct the flow of rotating magnetic flux. However, in this configuration, the radially inward extensions of the first and second flanges are approximately the same, so these flanges are less likely to obstruct the flow of rotating magnetic flux. Therefore, by adopting this configuration, it becomes possible to utilize the magnetic force of the permanent magnet more effectively.

[0015] The first flange and the second flange may extend radially inward and radially outward from the rotor, respectively.

[0016] In this case, while suppressing the radial extension length (projection length) on each side of the first and second flange portions, the length of the rib between the first and second flange portions can be made sufficiently long, thereby setting the magnetic flux resistance of the magnetic flux flowing through the rib to be sufficiently large.

[0017] The second gap may be provided with a third flange portion, which is thicker than the permanent magnet, at its outer end on the side that is spaced away from the magnetic pole centerline.

[0018] In this case, the length of the magnetic flux path between the outer end of the second air gap and the outer surface of the rotor increases, and as a result, the magnetic path resistance of the magnetic flux flowing through that path increases. This suppresses the leakage of magnetic flux near the outer end of the second air gap. Therefore, by adopting this configuration, it becomes possible to utilize the magnetic force of the permanent magnet more effectively, and further miniaturization and weight reduction of the permanent magnet becomes possible.

[0019] The components of the magnetic pole, including the magnet hole, the permanent magnet, the first void, the second void, and the rib, may be arranged in multiple layers in the radial direction.

[0020] In this case, the same functions as described above can be obtained by the components of the magnetic poles in each layer, and a greater rotational torque can be obtained by the components of the magnetic poles in multiple layers. [Effects of the Invention]

[0021] The rotating electrical machine according to the present invention is arranged such that the magnet holes straddle the magnetic pole center line, and ribs that connect the radially outer region and the inner region of the first air gap portion and the second air gap portion are arranged at one end side and the other end side in the extending direction of the magnet holes. Therefore, it is possible to suppress the intrusion of the magnet magnetic flux and the rotating magnetic flux in the vicinity of the magnetic pole center line, and to increase the mechanical strength of the rotor by the left and right ribs. Therefore, when the rotating electrical machine according to the present invention is adopted, it is possible to reduce the size and weight of the permanent magnet to be mounted.

Brief Description of the Drawings

[0022] [Figure 1] Cross-sectional view perpendicular to the axial direction of the rotating electrical machine of the first embodiment. [Figure 2] Cross-sectional view perpendicular to the axial direction of the rotor of the first embodiment. [Figure 3] Cross-sectional view of the rotor of the first embodiment showing the flow of magnetic flux in the rotor. [Figure 4] Schematic cross-sectional view of the rotor showing the deformation behavior of the rotor when the position of the rib is changed. [Figure 5] ​​​​​​​​​​​​​​​​​​​​​​​​A cross-sectional view of the rotor of the third embodiment, perpendicular to the axial direction. [Figure 14] A cross-sectional view of the rotor of the fourth embodiment, perpendicular to the axial direction. [Figure 15] A cross-sectional view of the rotor of the fifth embodiment, perpendicular to the axial direction. [Figure 16] A cross-sectional view of the rotor of the sixth embodiment, perpendicular to the axial direction. [Figure 17] An enlarged cross-sectional view of a portion of the rotor of the seventh embodiment. [Modes for carrying out the invention]

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments described below, common parts will be denoted by the same reference numerals, and some redundant explanations will be omitted.

[0024] <First Embodiment> Figure 1 is a diagram showing a cross-section of the rotating electric machine 1 of this embodiment that is perpendicular to the axial direction. The rotating electric machine 1 of this embodiment can be used, for example, as a power source for a vehicle. The rotating electric machine 1 comprises an annular stator 10 and a rotor 11 rotatably arranged radially inward of the stator 10. The rotating electric machine 1 of this embodiment is a magnet-synchronous rotating electric machine in which a plurality of permanent magnets 13A, 13B are embedded inside the rotor core 12 of the rotor 11.

[0025] The stator 10 comprises an annular stator core 16 with a plurality of teeth 15 formed on its inner periphery, and coils 17 wound around each tooth 15 of the stator core 16. The coils 17 are U-phase, V-phase, and W-phase coils and are connected to a drive circuit (not shown). The coils 17 wound around each tooth 15 are energized by a three-phase alternating current from the drive circuit, generating a rotating magnetic field on the inner periphery of the stator 10.

[0026] Figure 2 shows a cross-section of the rotor 11 perpendicular to the axial direction. As shown in Figures 1 and 2, the rotor 11 is formed in a cylindrical shape with a thick wall, and a rotating shaft (not shown) is fixed to its axial center. The rotor 11 and the rotating shaft are arranged coaxially with the inner surface of the stator 10 on the radially inward (inner circumference) side of the stator 10. A small gap is maintained between the inner surface of the stator 10 and the outer surface of the rotor 11. In this description of the embodiment, the direction in which the rotor 11 and the axis of rotation are oriented is referred to as the "axial direction," and the radial direction perpendicular to the axial direction and centered on the axis is referred to as the "radial direction." Furthermore, the circumferential direction centered on the axis is referred to as the "circumferential direction."

[0027] The rotor 11 comprises a rotor core 12 made of a magnetic material such as laminated steel sheet, and multiple pairs of permanent magnets 13A and 13B embedded inside the rotor core 12. Two permanent magnets 13A and 13B are spaced apart radially inward and outward, forming pairs, and multiple sets of these paired permanent magnets 13A and 13B are spaced apart around the circumferential region of the rotor core 12. The paired permanent magnets 13A and 13B are embedded in the rotor core 12 such that their magnetic poles face the same side radially. Furthermore, pairs of permanent magnets 13A and 13B adjacent to each other in the circumferential region have opposite poles facing radially outward. Multiple magnetic poles 18, each having a pair of permanent magnets 13A and 13B, are arranged at equal intervals around the circumferential region of the rotor 11.

[0028] Each magnetic pole 18 of the rotor 11 comprises a first magnetic pole component 18F located radially inward and a second magnetic pole component 18S located radially outward. That is, each magnetic pole 18 is composed of two layers of magnetic pole components (first magnetic pole component 18F and second magnetic pole component 18S).

[0029] The first magnetic pole component 18F includes a magnet hole 19, a permanent magnet 13A, a first air gap 21, a second air gap 22, and a rib 23.

[0030] The magnetic hole 19 extends circumferentially across the magnetic pole center line op (d-axis) which runs along the radial direction of the rotor 11. The magnetic hole 19 is a hole that penetrates the rotor core 12 in the axial direction. The shape of the magnetic hole 19 in an axial view is an arc shape with the arc center oa set at an arbitrary point radially outside the outer circumferential surface of the rotor 11 on the magnetic pole center line op. Both ends of the magnetic hole 19 in the extending direction are curved radially outward.

[0031] The permanent magnet 13A is formed in an arc shape when viewed axially and is inserted and positioned within the magnet hole 19 so as to straddle the magnetic pole center line op. The permanent magnet 13A is positioned in the central region in the extending direction of the magnet hole 19. The arc shape of the permanent magnet 13A is an arc shape with the same radius as the magnet hole 19, centered on the same arc center oa as the magnet hole 19. The permanent magnet 13A is fixed to the inner circumferential surface of the magnet hole 19 by press-fitting or adhesive. The length of the permanent magnet 13A in the extending direction is set to be sufficiently short compared to the length of the magnet hole 19 in the extending direction.

[0032] The first void 21 is a void formed between the ends of the magnet hole 19 in the extending direction and each end face of the permanent magnet 13A, and is provided so as to face the end faces of the permanent magnet 13A in the extending direction. The second void 22 is a void that extends from the magnet hole 19 at a distance from the magnet hole 19, on the extension of the ends of the magnet hole 19 in the extending direction, and has the same arc shape with the same radius centered on the same arc center oa as the first void 21. The second void 22 is composed of an arc-shaped hole that penetrates the rotor core 12 in the axial direction. The first void 21 and the second void 22 function as flux barriers that restrict the flow of magnetic flux on the outside of the extending direction of the permanent magnet 13A. Figure 3 is a cross-sectional view of the rotor 11, similar to Figure 2, showing the flow of magnetic flux within the rotor 11. As shown in the figure, the flow of magnetic flux within the rotor 11 is regulated by the first air gap 21 and the second air gap 22.

[0033] The ribs 23 are positioned between the first and second air gaps 21 and 22 on the left and right sides of the permanent magnet 13A. Each of the left and right ribs 23 extends substantially along the normal to the arc center oa. Each rib 23 connects the radial outer and inner regions of the first and second air gaps 21 and 22, thereby suppressing the reduction in the mechanical strength of the rotor core 12 caused by these air gaps 21 and 22.

[0034] The left and right ribs 23 are set to have an opening angle θRib with respect to the magnetic pole centerline op such that they satisfy the following equations (1) and (2). θ2 = (θ1 + θMag) / 2 …(1) θRib < θ² …(2)

[0035] The opening angles θMag, θRib, θ1, and θ2 in equations (1) and (2) (see Figure 2) are defined as follows. [Opening angle θMag] The angle of separation between the normal vector nm (for example, the normal vector centered at any point in the vicinity of the arc center oa) passing through the outer end of the permanent magnet 13A that is spaced away from the magnetic pole centerline op, and the magnetic pole centerline op. In the following, this opening angle θMag will be referred to as the "opening angle θMag of the permanent magnet." [Opening angle θRib] The angle of opening between the normal nr (for example, a normal centered at any point in the vicinity of the arc center oa) passing through the outer end of the first gap 21 that is spaced away from the magnetic pole centerline op, and the magnetic pole centerline op. In the following, this opening angle θRib will be referred to as "the opening angle θRib of rib 23". [Opening angle θ1] The angle of opening between the normal ns (for example, a normal centered at any point near the arc center oa) passing through the outer end of the second gap 22 that is spaced away from the magnetic pole centerline op, and the magnetic pole centerline op. In the following, this opening angle θ1 will be referred to as the "opening angle θ1 of the second gap 22". [Opening angle θ2] The angle of opening between the normal vector ni (for example, a normal vector centered at any point in the vicinity of the arc center oa) passing through an intermediate position between the outer end of the permanent magnet 13A that is spaced away from the magnetic pole centerline op and the outer end of the second gap 22 that is spaced away from the magnetic pole centerline op, and the magnetic pole centerline op. In the following, this opening angle θ2 will be referred to as the "opening angle θ2 at the midpoint of the void region."

[0036] Figure 4 is a schematic cross-sectional view of the rotor 11, showing the differences in deformation behavior of the rotor 11 when the position (opening angle θRib) of the rib 23 is changed, divided into (a), (b), and (c). In (a), the position of the rib 23 is set such that the opening angle θRib of the rib 23 is smaller than the opening angle θ2 at the intermediate position of the gap region. In (b), the position of the rib 23 is set such that the opening angle θRib of the rib 23 is the same as the opening angle θ2 at the midpoint of the gap region. In (c), the position of the rib 23 is set such that the opening angle θRib of the rib 23 is greater than the opening angle θ2 at the intermediate position of the gap region. Furthermore, the left half of each figure (a), (b), and (c) shows the state of the rotor 11 before deformation, while the right half of each figure shows the deformation behavior of the rotor 11 when a tensile load along the magnetic pole center line op is applied to the outer surface of the rotor 11. In the right half of each figure (a), (b), and (c), dots are marked in the areas where the stress exceeds a specified value.

[0037] As shown in Figures 4(a) and 4(b), when the opening angle θRib of the rib 23 is less than or equal to the opening angle θ2 at the midpoint of the gap region, the left and right ribs 23 receive the tensile load substantially along the magnetic pole centerline op as tension along the extension direction, and the deformation of the rotor 11 can be efficiently suppressed. On the other hand, as shown in Figure 4(c), when the opening angle θRib of the rib 23 is greater than the opening angle θ2 at the intermediate position of the gap region, when a tensile load acting on the rotor 11 substantially along the magnetic pole centerline op is generated, bending stress is generated in each rib 23, making it difficult to efficiently suppress the deformation of the rotor 11. Therefore, by setting the opening angle θRib of the rib 23 to be less than or equal to the opening angle θ2 at the intermediate position of the gap region, so as to satisfy equations (1) and (2) above, the deformation of the rotor 11 can be efficiently suppressed.

[0038] Furthermore, in this embodiment, the rotating electric machine 1 has a magnet hole 19 positioned so as to straddle the magnetic pole centerline op, and ribs 23 connecting the radial outer and inner regions of the first and second air gaps 21 and 22 are positioned on one end and the other end of the magnet hole 19 in the extending direction. As a result, as shown in Figure 3, magnetic flux leakage due to the wrapping of magnetic flux and rotating flux is less likely to occur in the vicinity of the magnetic pole centerline op, where the magnetic flux of the permanent magnet 13A and the rotational magnetic flux of the stator 10 tend to concentrate.

[0039] Figure 5 is an enlarged view of section V in Figure 1. As shown in Figure 5, the left and right first gaps 21 of the magnet hole 19 are provided with first flanges 24 at the ends facing the ribs 23, which are thicker than the permanent magnets 13A. In this embodiment, the first flanges 24 have an extended region 24a that extends radially inward along the normal nr to the general portion of the first gap 21 (the portion other than the first flanges 24). The first flanges 24 are thicker than the permanent magnets 13A by the length of the extended region 24a.

[0040] Furthermore, the left and right second gap portions 22 are provided with a second flange portion 25 at the end facing the rib 23, which is thicker than the permanent magnet 13A. In this embodiment, the second flange portion 25 has an extended region 25a that extends radially inward along the normal nr to the general portion of the second gap portion 22 (the portion other than the second flange portion 25). The second flange portion 25 is thicker than the permanent magnet 13A by the length of the extended region 25a. Therefore, the length of the rib 23 formed between the first gap 21 and the second gap 22 is longer than the thickness of the permanent magnet 13A by the amount of the extended regions 24a and 25a of each flange portion 24 and 25. Since the rib 23 is made up of a part of the rotor core 12 made of magnetic material, some of the magnetic flux and rotational flux flowing through the rotor core 12 may leak along the extension direction of the rib 23. However, since the rib 23 is set to a sufficient length in this way, the magnetic path resistance when magnetic flux flows becomes large. For this reason, leakage of magnetic flux through the rib 23 can be suppressed as much as possible.

[0041] Figure 6 is a graph showing the torque change rate of the rotating electric machine 1 when the thickness of the ends of the first gap 21 and the second gap 22 (the ends facing the rib 23) is changed. As shown in the figure, when the torque change rate is set to 0 when the thickness of the ends of the first gap 21 and the second gap 22 is the same as the thickness of the permanent magnet 13A, if the thickness of the ends of the first gap 21 and the second gap 22 is made thinner than the thickness of the permanent magnet 13A, the torque change rate increases in the negative direction approximately proportional to the decrease in thickness. Also, if the thickness of the ends of the first gap 21 and the second gap 22 is made thicker than the thickness of the permanent magnet 13A, the torque change rate increases in the positive direction approximately proportional to the increase in thickness. Therefore, as is clear from this figure, by providing the first flange portion 24 and the second flange portion 25 of sufficient thickness at the respective ends of the first gap portion 21 and the second gap portion 22, the rotational torque of the rotating electric machine 1 can be increased.

[0042] Figure 7 is a graph showing the torque change rate of the rotating electric machine 1 when the shape of the end of the second gap 22 (the end facing the rib 23) is changed. As shown in the figure, using the case where a first flange portion 24 is provided at the end of the first gap portion 21 and no flange portion is provided at the end of the second gap portion 22 as a baseline, if the extension length of the second flange portion 25 provided at the end of the second gap portion 22 is gradually increased from this state, the positive torque change rate of the rotating electric machine 1 will be maximized when the extension lengths of the first flange portion 24 and the second flange portion 25 become the same.

[0043] Figure 8 is a schematic cross-sectional view of the rotor 11 when the extension length of the second flange portion 25 is longer than the extension length of the first flange portion 24. As shown in Figure 8, if the length of the extended region 25a of the second flange 25 is made longer than the length of the extended region 24a of the first flange 24, the rotational magnetic flux flowing from the outer peripheral edge of the rotor core 12 along the extending direction of the second gap 22 is obstructed by the extended region 25a of the second flange 25. As a result, the rotational magnetic flux cannot be fully utilized to increase the rotational torque of the rotating electric machine 1. Therefore, by making the extended lengths of the extended regions 24a and 25a of the first flange 24 and the second flange 25 the same, the rotational torque of the rotating electric machine 1 can be further increased.

[0044] Figure 9 is an enlarged view of section IX in Figure 1. As shown in Figure 9, magnetic flux from the magnet or rotational flux may attempt to wrap around the region between the outer end of the second gap 22 in the extending direction (the end that is spaced away from the magnetic pole centerline op) and the outer circumferential surface of the rotor core 12.

[0045] Figure 10 is a graph showing the torque change rate of the rotating electric machine 1 when the shape of the outer end of the second gap 22 (the end that is spaced away from the magnetic pole center line op) is changed. As shown in Figure 10, increasing the thickness of the outer end of the second air gap 22 increases the torque change rate of the rotating electric machine 1 in a positive direction. In other words, it is desirable to provide a third flange 40 that is thicker than the permanent magnet 13A at the outer end of the second air gap 22 that is spaced away from the magnetic pole center line op. This allows the torque change rate of the rotating electric machine 1 to be increased in a positive direction. This is because increasing the thickness of the outer end of the second air gap 22 (providing the third flange 40 at the outer end) lengthens the region between the outer end of the second air gap 22 and the outer circumferential surface of the rotor core 12, and as a result, the magnetic path resistance of the magnetic flux flowing through the region increases. Therefore, by providing a third flange 40 that is thicker than the permanent magnet 13A at the outer end of the second air gap 22, the rotational torque of the rotating electric machine 1 can be increased.

[0046] Furthermore, the second magnetic pole component 18S shown in Figure 1 comprises a magnet hole 26, a permanent magnet 13B, and an air gap 27. The magnet hole 26 of the second magnetic pole component 18S is a hole that penetrates the rotor core 12 in the axial direction and extends so as to straddle the magnetic pole centerline op in the circumferential direction. The shape of the magnet hole 26 in an axial view is an arc shape with the arc center at an arbitrary point radially outside the outer circumferential surface of the rotor 11 on the magnetic pole centerline op. Similar to the magnet hole 19 of the first magnetic pole component 18F, both ends of the magnet hole 26 in the extending direction are curved radially outward.

[0047] The permanent magnet 13B is formed in an arc shape when viewed axially and is inserted and positioned within the magnet hole 26 so as to straddle the magnetic pole centerline op. The permanent magnet 13B is positioned in the central region in the extending direction of the magnet hole 26. The permanent magnet 13B is fixed to the inner circumferential surface of the magnet hole 26 by press-fitting or adhesive.

[0048] The length of the permanent magnet 13B in the extending direction is set to be sufficiently short compared to the length of the magnet hole 26 in the extending direction. There are gaps 27 between the ends of the permanent magnet 13B in the extending direction and the ends of the magnet hole 26 in the extending direction. The gaps 27 located on both sides of the permanent magnet 13B function as flux barriers to regulate the flow of magnetic flux and rotational magnetic flux.

[0049] As described above, in this embodiment, the rotating electric machine 1 has a magnet hole 19 of the first magnetic pole component 18F arranged to straddle the magnetic pole centerline op, and ribs 23 connecting the radial outer and inner regions of the first and second air gaps 21 and 22 are arranged on one end and the other end of the magnet hole 19 in the extending direction. Therefore, magnetic flux leakage due to the wrapping of magnetic flux and rotating flux is less likely to occur in the vicinity of the magnetic pole centerline op, where magnetic flux from the magnet and magnetic flux from the rotation tend to concentrate. The ribs 23 are formed such that the opening angle θRib satisfies the above equations (1) and (2), so that bending stress is less likely to occur in the ribs 23 when a tensile load is applied in a direction substantially along the magnetic pole centerline op. Therefore, the mechanical strength of the rotor 11 can be maintained at a high level. Therefore, when the rotating electric machine 1 of this embodiment is adopted, the leakage of magnetic flux and rotational flux in the vicinity of the magnetic pole center line op can be suppressed, and the mechanical strength of the rotor 11 can be increased by the left and right ribs 23. Thus, when the rotating electric machine 1 of this embodiment is adopted, the size and weight of the permanent magnet 13A to be mounted can be reduced, contributing to energy efficiency.

[0050] Furthermore, in this embodiment, the rotating electric machine 1 is provided with a first flange portion 24 thicker than the permanent magnet 13A at the end of the first air gap portion 21 facing the rib 23, and a second flange portion 25 thicker than the permanent magnet 13A at the end of the second air gap portion 22 facing the rib 23. Therefore, the length of the rib 23 in the extending direction formed between the first air gap portion 21 and the second air gap portion 22 can be made sufficiently long, increasing the magnetic path resistance of the magnetic flux trying to flow through the rib 23. This makes it possible to further suppress the wrapping around of magnet magnetic flux and rotating magnetic flux passing through the rib 23. Therefore, by adopting the rotating electric machine 1 of this embodiment, it becomes possible to utilize the magnetic force of the permanent magnet 13A more effectively, and to further reduce the size and weight of the permanent magnet 13A.

[0051] Furthermore, in the rotating electric machine 1 of this embodiment, the radially inward extension lengths of the first flange portion 24 and the second flange portion 25 are set to be approximately the same length. Therefore, the flange portion with the longer extension length does not obstruct the flow of the rotating magnetic flux. Consequently, when the rotating electric machine 1 with this configuration is adopted, it becomes possible to utilize the magnetic force of the permanent magnet 13A more effectively.

[0052] Furthermore, in the rotating electric machine 1 of this embodiment, a third flange portion 40, which is thicker than the permanent magnet 13A, is provided at the outer end of the second air gap portion 22 on the side that is spaced away from the magnetic pole center line op. As a result, the length of the magnetic flux path between the outer end of the second air gap portion 22 and the outer surface of the rotor core 12 (rotor 11) is increased, and the magnetic path resistance of the magnetic flux flowing through that magnetic flux path increases. As a result, the leakage of magnetic flux near the outer end of the second air gap portion 22 is suppressed. Therefore, by adopting this configuration, it becomes possible to utilize the magnetic force of the permanent magnet 13A more effectively, and it becomes possible to further miniaturize and lighten the permanent magnet 13A.

[0053] <Second Embodiment> Figure 11 is a cross-sectional view similar to Figure 5, showing an enlarged portion of the rotor 11 of this embodiment. The basic configuration of the rotating electric machine in this embodiment is substantially the same as that of the first embodiment. However, in the first embodiment, the first flange portion 24 of the first gap portion 21 and the second flange portion 25 of the second gap portion 22 extend only radially inward, whereas in this embodiment, the first flange portion 124 and the second flange portion 125 extend not only radially inward but also radially outward. In this embodiment, the radially inward extension length and the radially outward extension length of the first flange portion 124 and the second flange portion 125 are substantially the same.

[0054] Figure 12 is a graph showing the torque change rate of the rotating electric machine when the shape of the ends of the first gap 21 and the second gap 22 (the ends facing the rib 23) is changed. As shown in the figure, when the thickness of the ends of the first gap 21 and the second gap 22 is made thinner than the thickness of the permanent magnet 13A, the torque change rate increases in the negative direction approximately proportional to the decrease in thickness, and when the thickness of the ends of the first gap 21 and the second gap 22 is made thicker than the thickness of the permanent magnet 13A, the torque change rate increases in the positive direction approximately proportional to the increase in thickness. Furthermore, when the first flange 124 and the second flange 125 formed at the respective ends of the first gap 21 and the second gap 22 are extended on both the radially inward and outward sides, the extension length of the rib 23 can be increased while suppressing an increase in the extension length per side.

[0055] Since the basic configuration of the rotating electric machine of this embodiment is the same as that of the first embodiment, the same basic effects as those of the first embodiment described above can be obtained. In addition, in this embodiment, since the first flange portion 124 and the second flange portion 125 extend to both the radially inward and radially outward sides of the rotating electric machine, the extension length per side required to obtain the same magnetic flux leakage prevention effect can be shortened compared to when the first flange portion 124 and the second flange portion 125 extend only to one of the radially inward or radially outward sides.

[0056] <Third Embodiment> Figure 13 shows a cross-section of the rotor 211 in this embodiment perpendicular to the axial direction. In this embodiment, the configuration of the first magnetic pole component 18F of each magnetic pole 18 is the same as that of the first embodiment, but the configuration of the second magnetic pole component 218S of each magnetic pole 18 is different from that of the first embodiment. The second magnetic pole component 218S of this embodiment has a configuration that is substantially the same as that of the first magnetic pole component 18F.

[0057] The second magnetic pole component 218S is positioned radially outward from the first magnetic pole component 18F and is spaced apart from it. It comprises a magnet hole 30, a permanent magnet 13B, a first air gap 31, a second air gap 32, and a rib 33.

[0058] The magnetic hole 30 extends so as to straddle the magnetic pole centerline op (d-axis) in the circumferential direction. The magnetic hole 30 is a hole that penetrates the rotor core 12 in the axial direction. The shape of the magnetic hole 30 in an axial view is an arc shape with the arc center at an arbitrary point radially outside the outer surface of the rotor 211 on the magnetic pole centerline op. Both ends of the magnetic hole 30 in the extending direction are curved radially outward.

[0059] The permanent magnet 13B is formed in an arc shape when viewed in the axial direction and is inserted and positioned within the magnet hole 30 so as to straddle the magnetic pole center line op. The permanent magnet 13B is positioned in the central region in the extending direction of the magnet hole 30. The permanent magnet 13B is fixed to the inner circumferential surface of the magnet hole 30 by press-fitting or adhesive.

[0060] The first void 31 is a void formed between the ends of the magnet hole 30 in the extending direction and each end face of the permanent magnet 13B, and is provided so as to face the end faces of the permanent magnet 13B in the extending direction. The second void 32 is a void that extends from the magnet hole 30, spaced apart from the magnet hole 30, on the extension of the ends of the magnet hole 30 in the extending direction. The second void 32 is formed in the shape of an arc with the same radius and centered on the same arc center as the first void 31. The first void 31 and the second void 32 function as flux barriers that restrict the flow of magnetic flux on the outside of the extending direction of the permanent magnet 13B.

[0061] The ribs 33 are positioned between the first and second air gaps 31 and 32 on the left and right sides of the permanent magnet 13B. Each of the left and right ribs 33 extends substantially along the normal to the arc center of the magnet hole 30 and the second air gap 32. Each rib 33 connects the radial outer and inner regions of the first and second air gaps 31 and 32, respectively.

[0062] The rib 23 is set to have an opening angle θRib with respect to the magnetic pole centerline op such that it satisfies equations (1) and (2) described in the description of the first embodiment. However, when applying equations (1) and (2) to the second magnetic pole component 218S, the definitions of the opening angles θMag, θRib, θ1, and θ2 shall be reinterpreted as follows. [Opening angle θMag] The angle of separation between the normal line passing through the outer end of the permanent magnet 13B that is spaced away from the magnetic pole centerline op, and the magnetic pole centerline op. [Opening angle θRib] The angle of separation between the normal line passing through the outer end of the first gap 31 that is spaced away from the magnetic pole centerline op and the magnetic pole centerline op. [Opening angle θ1] The angle of opening between the normal passing through the outer end of the second gap 32 that is spaced away from the magnetic pole centerline op and the magnetic pole centerline op. [Opening angle θ2] The normal line passing through the intermediate position between the outer end of the permanent magnet 13B that is spaced away from the magnetic pole centerline op and the outer end of the second gap 32 that is spaced away from the magnetic pole centerline op, and the opening angle between the magnetic pole centerline op and op.

[0063] As described above, the rotating electric machine of this embodiment is equipped with a first magnetic pole component 18F having the same configuration as the first embodiment, and therefore the same basic effects as the first embodiment described above can be obtained. In addition, in this embodiment, the rotating electric machine has a second magnetic pole component 218S, which has substantially the same configuration as the first magnetic pole component 18F, arranged radially outward from each first magnetic pole component 18F. Therefore, a larger rotational torque can be obtained by having multiple magnetic poles (magnetic pole components) arranged radially.

[0064] <Fourth Embodiment> Figure 14 shows a cross-section of the rotor 311 in this embodiment perpendicular to the axial direction. The rotating electric machine of this embodiment includes a first magnetic pole component 18F similar to that of the first embodiment. However, it does not include the second magnetic pole component 18S of the first embodiment or the second magnetic pole component 218S of the third embodiment.

[0065] Although the rotating electric machine of this embodiment does not have the second magnetic pole components 18S and 218S, it has the first magnetic pole component 18F, and therefore can obtain the same basic effects as the first embodiment described above.

[0066] <Fifth Embodiment> Figure 15 shows a cross-section of the rotor 411 in this embodiment perpendicular to the axial direction. The basic configuration of the rotating electric machine in this embodiment is the same as that of the third embodiment shown in Figure 13. That is, the first magnetic pole component 18F and the second magnetic pole component 218S, which have the same configuration, are arranged in two layers in the radial direction of the rotor 411. However, in the third embodiment shown in Figure 13, one permanent magnet 13A and one 13B, which have a substantially arc shape in axial view, are housed in the magnet hole 19 of the first magnetic pole component 18F and the magnet hole 30 of the second magnetic pole component 218S, respectively. In contrast, in the rotating electric machine of this embodiment, two permanent magnets 413A and 413B, which have a substantially rectangular shape in axial view, are housed in the magnet hole 19 of the first magnetic pole component 18F and two permanent magnets 413A and two 413B, respectively.

[0067] Each of the magnet holes 19 and 30 houses a pair of permanent magnets 413A and 413B, but the permanent magnets 413A and 413B in each pair are positioned in close proximity without any gaps.

[0068] Since the rotating electric machine of this embodiment has a basic configuration that is almost the same as that of the third embodiment, the same basic effects as those of the third embodiment described above can be obtained. In addition, in this embodiment, the permanent magnets 413A and 413B housed in the respective magnet holes 19 and 30 are composed of a pair of segmented pieces that are substantially rectangular in axial view. This simplifies the shape of each permanent magnet 413A and 413B, making it easier to manufacture them. In particular, as in this embodiment, when the shape and size of all permanent magnets 413A and 413B are set to be the same, productivity improves and product costs can be reduced.

[0069] <Sixth Embodiment> Figure 16 shows a cross-sectional view of the rotor 511 in this embodiment, perpendicular to the axial direction. The rotating electric machine of this embodiment has a configuration almost identical to that of the fifth embodiment, but differs from that of the fifth embodiment in that the permanent magnet 513A housed in the magnet hole 19 of the first magnetic pole component 18F is composed of three divided pieces that are substantially rectangular in axial view. The permanent magnet 513A consists of three magnets of the same shape and size. The three segments of the permanent magnet 513A are positioned so that the central segment straddles the magnetic pole centerline op.

[0070] The rotating electric machine of this embodiment can achieve the same effects as that of the fifth embodiment, and the central permanent magnet 513A (central segmented piece) housed in the magnet hole 19 is positioned across the magnetic pole centerline op, and the three permanent magnets 513A are housed in the magnet hole 19 in a smooth arc. As a result, the magnetic flux of the magnets and the rotational magnetic flux can be utilized more effectively without loss.

[0071] <Seventh Embodiment> Figure 17 is an enlarged cross-sectional view showing a portion of the rotor 611 of this embodiment. The rotating electric machine of this embodiment differs from that of the other embodiments described above in the shape of the magnet hole 619 including the first gap 621 and the shape of the second gap 622 which is located outside the extending direction of the first gap 621.

[0072] The magnet hole 619 extends so as to straddle the magnetic pole centerline op in the circumferential direction, and has a roughly V-shape in which it opens radially outward when viewed axially. The magnet hole 619 has inclined hole components 619a and 619b of a constant width that extend to the left and right, inclined radially outward, with the magnetic pole centerline op as the center. A permanent magnet 413A, which has a roughly rectangular shape when viewed axially, is housed in each hole component 619a and 619b. An air gap is secured between the extending ends of each hole component 619a and 619b and the permanent magnet 413A, and this air gap is referred to as the first air gap 621. In this embodiment, the magnet hole 619 is precisely V-shaped when viewed in the axial direction, but it can also be said to have a roughly arc-shaped form such that both ends in the extending direction are close to the outer edge of the rotor 611.

[0073] The second void 622 extends linearly along the extension of the ends of each hole component 619a, 619b in the extending direction, at the same angle as the inclination angle of each hole component 619a, 619b. The second void 622 is provided at a predetermined width distance from the adjacent first void 621. A rib 23 is provided between the first void 621 and the second void 622.

[0074] Although the shape of the magnet hole 619 including the first gap 621 and the shape of the second gap 622 differ from those of the other embodiments described above, the basic configuration itself remains unchanged, and therefore the same basic effects as those of the other embodiments described above can be obtained.

[0075] It should be noted that the present invention is not limited to the embodiments described above, and various design modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0076] 1… Rotating electric machine 10…Status 11,211,311,411,511,611… Rotor 13A,13B,413A,413B,513A...Permanent magnet 18...Magnetic pole 19,30,619…Magnetic holes 21,31,621...first cavity 22,32,622…Second cavity 23,33… Ribs 24,124...First guard section 25,125...Second guard section 40... Third guard section nm,nr,ns,ni…normal op…Magnetic pole center line

Claims

1. A ring-shaped stator, The stator comprises a rotor rotatably arranged radially inward and having multiple magnetic poles spaced apart in the circumferential direction, The magnetic poles of the rotor are A magnetic hole is formed in an arc shape with the center of the arc at an arbitrary point radially outside the outer surface of the rotor on the magnetic pole center line, such that the magnetic pole center line extends circumferentially along the radial direction of the rotor, and both ends in the extending direction are close to the outer edge of the rotor, and the arc center is at an arbitrary point radially outside the outer surface of the rotor on the magnetic pole center line when viewed in the axial direction, A permanent magnet is inserted and positioned along the arc-shaped magnet hole, and is formed in an arc shape with the same radius as the magnet hole, with the same arc center as the magnet hole when viewed in the axial direction, A first gap in the shape of an arc with the same radius centered on the arc center, formed between the ends of the magnet hole in the extending direction and the permanent magnet, A second gap portion, which is arc-shaped and has the same radius as the center of the arc, extends from the magnetic hole, spaced apart from the magnetic hole, along the extension of both ends in the extending direction of the magnetic hole, The structure comprises a rib positioned between the first void and the second void, connecting the radial outer region and the inner region of the first void and the second void, Let θMag be the angle of separation between the normal line passing through the outer end of the permanent magnet that is spaced away from the magnetic pole centerline and the magnetic pole centerline. Let θRib be the angle of separation between the normal line passing through the outer end of the first gap that is spaced away from the magnetic pole centerline and the magnetic pole centerline. Let θ1 be the angle of separation between the normal line passing through the outer end of the second gap that is spaced away from the magnetic pole centerline and the magnetic pole centerline. When the normal line passing through the intermediate position between the outer end of the permanent magnet that is spaced away from the magnetic pole centerline and the outer end of the second gap that is spaced away from the magnetic pole centerline, and the angle of opening between the magnetic pole centerline and the normal line is θ2, A rotating electric machine characterized in that the opening angle θRib is set to satisfy the following equations (1) and (2). θ2=(θ1+θMag) / 2…(1) θRib < θ² …(2)

2. The first void portion is provided with a first flange portion at the end facing the rib, which is thicker than the permanent magnet. The rotating electric machine according to claim 1, characterized in that the second gap portion has a second flange portion that is thicker than the permanent magnet at the end portion facing the rib.

3. The rotating electric machine according to claim 2, characterized in that the first flange portion and the second flange portion have substantially the same extension length radially inward of the rotor.

4. The rotating electric machine according to claim 2, characterized in that the first flange portion and the second flange portion extend radially inward and radially outward, respectively, of the rotor.

5. The rotating electric machine according to claim 1, characterized in that the second gap portion is provided with a third flange portion having a greater thickness than the permanent magnet at the outer end portion on the side that is spaced away from the magnetic pole centerline.

6. The rotating electric machine according to claim 1, characterized in that the components of the magnetic pole, which include the magnet hole, the permanent magnet, the first void, the second void, and the rib, are arranged in multiple layers in the radial direction.

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