Rotors for rotating electrical machines

Abstract

The present invention provides a rotor for a rotating electric machine in which a cavity is provided as close to the magnet as possible while suppressing obstruction of the passage of the magnet magnetic flux. In the present invention, an arc having a vertex S2 as the center and passing through the inner peripheral corners (bi, ci) of a first magnet (b, c) provided on the inner peripheral side of the rotor core is set as a boundary imaginary line (Lm), and a cooling hole (cavity) (42) is provided on the inner peripheral side of the rotor core relative to the boundary imaginary line (Lm). Therefore, the cooling hole (42) is suppressed from obstructing the passage of the magnet magnetic flux, and a decrease in the motor torque or motor efficiency caused by the cooling hole (42) is suppressed. Furthermore, since the q-axis magnetic flux passage width (Wq2) on the cooling hole (42) side is smaller than the q-axis salient pole width (Wq1) at the intersection (P) with the boundary imaginary line (Lm) on the shortest line segment (Ls) between the first magnet (b, c) and the cooling hole (42), the cooling hole (42) is arranged at a position as close to the first magnet (b, c) as possible while ensuring the passage cross section of the magnet magnetic flux and the stator magnetic flux, thereby appropriately obtaining the cooling performance of the first magnet (b, c) achieved by the cooling hole (42).

Description

Technical Field

[0001] The present invention relates to a rotor for a rotating electrical machine, and more particularly to a technology capable of appropriately defining the position of a cavity. Background Art

[0002] There is known a rotor for a rotating electric machine, which has a cylindrical rotor core, and a pair of flux barriers having magnet mounting portions are symmetrically provided on both sides of the rotor core in the circumferential direction with the q-axis being sandwiched therebetween, and magnets are provided on the magnet mounting portions, and a cavity portion is provided on the q-axis, and a stator flux passes along the q-axis. The technology described in Patent Document 1 is an example thereof. In Patent Document 1, the magnets on both sides of the q-axis are arranged in an inverted V-shaped posture, and since the magnetic resistance increases as the spacing distance increases toward the inner circumference, it can be considered that there is almost no magnetic line of force flowing on the inner circumference side of the rotor core compared to the arc at the middle position of the connecting magnets, and thus a cavity portion is provided on the inner circumference side of the rotor core compared to the arc (see Patent Document 1). Figure 2 ).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6042976 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, in Patent Document 1, since the cavity is provided on the line connecting the inner circumferential ends of the pair of magnets, and magnetic lines of force pass between these inner circumferential ends, there is a possibility that the cavity will obstruct the passage of the magnet magnetic flux, thereby reducing the magnetic flux and lowering the motor torque. Furthermore, the increased magnetic flux density increases iron loss, further reducing motor efficiency. While moving the cavity away from the magnets eliminates the possibility of obstructing the passage of the magnet magnetic flux, this will reduce the cooling performance of the magnets, resulting in a decrease in motor torque due to demagnetization caused by overheating.

[0008] The present invention has been made against the background of the above-mentioned actual situation, and its object is to provide a cavity as close to the magnet as possible while suppressing the obstruction of the passage of the magnet's magnetic flux.

[0009] Methods for solving problems

[0010] In order to achieve the objects involved, the first invention is a rotor for a rotating electric machine, which has a cylindrical rotor core, and on which a pair of flux barriers having magnet mounting portions are symmetrically arranged on both sides of the circumferential direction with a q axis sandwiched therebetween, wherein a magnet is arranged in the magnet mounting portion, a cavity is provided on the q axis, and a stator flux passes along the q axis. In the rotor for the rotating electric machine, it is characterized in that: (a) a pair of first magnets are provided as the magnets in the pair of flux barriers in a symmetrical manner with the q axis sandwiched therebetween, and the cross-section of the first magnets at right angles to the center line of the rotor shaft is a rectangular cross-section and is arranged in an inverted V-shape that expands as it approaches the inner circumference of the rotor core; and on the other hand, (b) the pair of flux barriers provided on both sides of the q axis are symmetrically arranged. The shortest distance between them is set as the q-axis salient pole width Wq1 through which the stator magnetic flux passes, (c) a straight line connecting the inner circumferential corner of the rotor core located closest to the inner circumference of the respective corners of the pair of first magnets, or an arc protruding toward the inner circumference of the rotor core compared to the straight line is set as the magnetic flux of the first magnet, that is, the boundary imaginary line Lm of the magnet magnetic flux, (d) the cavity is arranged on the inner circumference side of the rotor core compared to the boundary imaginary line Lm, and (e) when the line segment connecting the closest part between the first magnet and the cavity is set as the shortest line segment Ls, and the length on the shortest line segment Ls on the cavity side compared to the intersection P with the boundary imaginary line Lm is set as the q-axis magnetic flux passing width Wq2, the q-axis magnetic flux passing width Wq2 is smaller than the q-axis salient pole width Wq1.

[0011] The second invention is a rotor for a rotating electrical machine according to the first invention, characterized in that: (a) in the pair of flux barriers, a pair of second magnets are provided as the magnets on the outer peripheral side of the rotor core relative to the first magnets in a symmetrical manner with respect to the q-axis, and the second magnets have a rectangular cross-section at right angles to the center line of the rotor shaft and are arranged in an inverted V-shape that expands as it approaches the inner peripheral side of the rotor core; and (b) the boundary imaginary line Lm is an arc centered at the vertex S2 of the inverted V-shape of the second magnet and passing through the inner peripheral corners of the pair of first magnets.

[0012] A third invention is the rotating electrical machine rotor according to the first invention, wherein the virtual boundary line Lm is a straight line connecting the inner peripheral corner portions of the pair of first magnets.

[0013] The fourth invention is a rotor for a rotating electrical machine according to any one of the first to third inventions, characterized in that: (a) in the rotor core, at least two magnetic flux barriers are arranged in a V-shaped or U-shaped V-shaped pattern in a manner that expands as it approaches the outer peripheral side as a group, and multiple groups are arranged at equal angular intervals around the center line of the rotor shaft; (b) the middle line of two groups of V-shaped configuration patterns adjacent to each other in the circumferential direction is the q-axis, and the pair of magnetic flux barriers located on both sides closest to the q-axis are the pair of magnetic flux barriers symmetrically arranged on both sides in the circumferential direction with the q-axis sandwiched therebetween.

[0014] A fifth invention is the rotating electrical machine rotor according to any one of the first to fourth inventions, wherein the q-axis magnetic flux passage width Wq2 is smaller than the q-axis salient pole width Wq1 and is equal to or greater than 1 / 2 of the q-axis salient pole width Wq1.

[0015] Effects of the Invention

[0016] In this rotating electric machine rotor, a straight line or arc passing through the inner circumferential corners of a pair of symmetrically arranged first magnets sandwiching the q-axis is defined as the imaginary boundary line Lm, and a cavity is provided closer to the inner circumference of the rotor core than this imaginary boundary line Lm. This prevents the cavity from obstructing the passage of magnet magnetic flux, thereby suppressing a decrease in motor torque and efficiency due to the cavity. Furthermore, since the length of the shortest line segment Ls between the first magnet and the cavity, closer to the cavity than the intersection point P with the imaginary boundary line Lm, is defined as the q-axis magnetic flux passage width Wq2, which is smaller than the q-axis salient pole width Wq1, the shortest distance between the magnetic flux barriers on either side of the q-axis. Therefore, while ensuring a sufficient cross-sectional area for the passage of magnet magnetic flux and stator magnetic flux, the cavity is provided as close to the first magnet as possible, thereby achieving optimal cooling performance for the first magnet by the cavity and suppressing a decrease in motor torque due to overheating and demagnetization. Since the stator magnetic flux passing through the q-axis salient pole width Wq1 is divided into two directions by the cavity portion, even if the q-axis magnetic flux passing width Wq2 is smaller than the q-axis salient pole width Wq1, the stator magnetic flux passing cross section can be ensured.

[0017] In the second invention, since the boundary imaginary line Lm is a circular arc centered on the vertex S2 of the inverted V shape of the second magnet arranged on the outer peripheral side of the rotor core compared to the first magnet and passing through the inner peripheral corners of a pair of first magnets, the boundary imaginary line Lm is close to the boundary line of the magnet flux of the first magnet, thereby appropriately obtaining the effect of the first invention.

[0018] In the third invention, by defining the imaginary boundary line Lm as the straight line connecting the inner circumferential corners of the pair of first magnets and providing the cavity on the inner circumferential side of the rotor core relative to the imaginary boundary line Lm, the effects of the first invention, such as reduced obstruction of the magnet magnetic flux, are achieved more effectively than in the case of providing the cavity on the straight line connecting the inner circumferential corners as in Patent Document 1. This third invention is substantially equivalent to the second invention, in which the vertex S2 is infinitely spaced from the inner circumferential corners of the first magnets.

[0019] In the fourth invention, the present invention is preferably applied in the following case, that is, a V-shaped or U-shaped V-shaped configuration pattern of the magnetic flux barrier is taken as a group, and multiple groups are arranged around the center line of the rotor core, the middle line of the two groups of V-shaped configuration patterns adjacent in the circumferential direction is the q-axis, and a pair of magnetic flux barriers located on both sides closest to the q-axis are configured to form an inverted V-shaped posture.

[0020] In the fifth invention, since the q-axis magnetic flux passage width Wq2 is smaller than the q-axis salient pole width Wq1 and is at least 1 / 2 of the q-axis salient pole width Wq1, a cavity portion can be provided near the first magnet, thereby ensuring cooling performance for the first magnet while also appropriately securing a sufficient cross-section for the passage of the magnet magnetic flux and the stator magnetic flux. Specifically, since the stator magnetic flux passing through the q-axis salient pole width Wq1 is bifurcated by the cavity portion, by making the q-axis magnetic flux passage width Wq2 smaller than the q-axis salient pole width Wq1 and at least 1 / 2 of the q-axis salient pole width Wq1, an adequate cross-section for the passage of the stator magnetic flux can be secured. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic cross-sectional view for explaining a rotating electrical machine including a rotor for a rotating electrical machine according to one embodiment of the present invention.

[0022] Figure 2 It is a cross-sectional view of the rotor at right angles to the center line O, and is a view showing a 1 / 4 portion around the center line O in an enlarged manner.

[0023] Figure 3 To further amplify Figure 2 The diagram shows the portion of the rotor near the q-axis.

[0024] Figure 4 FIG. 1 is a diagram illustrating another embodiment of the present invention and is similar to FIG. Figure 3 The corresponding enlarged view of the part near the q-axis. DETAILED DESCRIPTION

[0025] A rotating electrical machine, sometimes also called a rotating machine, is a rotating electrical machine that can be a motor, a generator, or a motor-generator used for both, such as a permanent magnet synchronous motor. While rare earth magnets are preferred, other permanent magnets may also be used. The flux barriers are arranged in a V-shaped or U-shaped pattern that expands toward the outer circumference of the rotor core. Multiple sets of V-shaped or U-shaped V-shaped patterns are arranged at equal angular intervals around the centerline of the rotor core, with the midline between two circumferentially adjacent V-shaped patterns being the q-axis. A pair of flux barriers located closest to the q-axis are symmetrically arranged to form an inverted V-shape. However, the arrangement pattern of the flux barriers can be arbitrarily specified. While one or more magnets are arranged in the flux barrier, for example, with predetermined cavities, the magnets may be embedded throughout the entire flux barrier. The flux barrier may also be divided into multiple pieces, with the first and second magnets arranged in each flux barrier.

[0026] While cooling holes, through which cooling fluid flows as needed, are suitable as the cavity, weight-saving holes, etc., are also possible. For example, a straight line connecting the inner corners of a pair of first magnets, or an arc passing through the inner corners of the first magnets with vertex S2 of the inverted V-shaped outer-circumferential second magnet as its center, are suitable for the imaginary boundary line Lm. However, various other configurations are also possible, such as an arc passing through the inner corners of the first magnets with vertex S1 of the inverted V-shaped outer-circumferential second magnet as its center. Preferably, an arc centered at a point closer to the outer circumference of the rotor core than vertex S1 is used. While the angle of vertex S2 of the inverted V-shaped outer-circumferential second magnet is smaller than the angle of vertex S1 of the inverted V-shaped outer-circumferential first magnet, it can also be the same as or greater than the angle of vertex S1. The outer-circumferential second magnet can also be omitted. While the q-axis magnetic flux passage width Wq2 is preferably smaller than the q-axis salient pole width Wq1 and at least 1 / 2 of the q-axis salient pole width Wq1, it can also be less than 1 / 2 of the q-axis salient pole width Wq1. The rectangular cross section of the magnet may be formed, for example, by arranging a plurality of magnets in close contact with each other so as to form a rectangular cross section as a whole.

[0027] [Example]

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the drawings are appropriately simplified or deformed for the purpose of explanation, and the dimensional ratios, angles, shapes, etc. of each part are not necessarily accurately depicted.

[0029] Figure 1The diagram is a schematic cross-sectional view taken along a center line O for explaining a rotating electrical machine 10 including a rotating electrical machine rotor 12 (hereinafter simply referred to as a rotor 12 ) as one embodiment of the present invention. Figure 2 This is a cross-sectional view of the rotor 12 at right angles to the centerline O, showing an enlarged 1 / 4 portion (90° angle range). This rotating electrical machine 10 is a permanent magnet embedded synchronous motor and a motor-generator capable of operating as either a motor or a generator. It is suitable for use as a driving force source for electric vehicles, including hybrid vehicles, for example. The rotating electrical machine 10 includes a rotor 12 and a stator 14, which are arranged concentrically with the centerline O. In the description of this embodiment, the centerline O of the rotating electrical machine 10 will be used as the centerline of the rotor 12, stator 14, and rotor shaft 20. The stator 14 includes a cylindrical stator core 16 disposed on the outer periphery of the rotor 12 and a plurality of stator coils 18 wound around the stator core 16. The stator core 16 is formed by stacking a large number of annular steel plates in an axial direction, that is, parallel to the centerline O, perpendicular to the centerline O. The stator core 16 is secured to a housing (not shown) by press-fitting or bolting.

[0030] The rotor 12 includes a cylindrical rotor core 22 mounted on the outer circumference of a rotor shaft 20, and a large number of magnets 24 embedded in the rotor core 22. The rotor core 22 is formed by stacking a large number of annular steel plates perpendicular to the centerline O and in the axial direction, that is, parallel to the centerline O. A pair of end plates 30, 30 are provided at each end of the rotor core 22, securing it to the rotor shaft 20. A flange 32 is provided on the rotor shaft 20, and a nut 34 is screwed onto the flange 32. The rotor core 22 is clamped and secured to the rotor shaft 20 between the flange 32 and the nut 34. The magnets 24 are rare earth magnets and, if necessary, are covered with an insulating film.

[0031] like Figure 2 As shown, on the rotor core 22, four types of flux barriers 40a, 40b, 40c, and 40d (hereinafter referred to as flux barriers 40 unless otherwise specified) are provided so as to penetrate in the axial direction, and magnets 24 are inserted into the magnet mounting portions of the flux barriers 40 and fixed in a certain posture by adhesive or the like. Figure 2In the figure, the magnets 24 are represented by six different types of magnets, A, a, B, b, C, and c. In the following description, the magnets 24 will be referred to as magnets A, a, B, b, C, and c as needed. Magnets A, a, B, b, C, and c all have rectangular cross-sections perpendicular to the centerline O, and each has a rectangular parallelepiped shape with approximately the same length as the rotor core 22. Magnet A is mounted in flux barrier 40a, magnet a is mounted in flux barrier 40b, two magnets B and b are mounted in flux barrier 40c, and two magnets C and c are mounted in flux barrier 40d. The flux barriers 40c and 40d are long strips bent midway, with magnets B, b, C, and c fixed to either side of the bent portion. Furthermore, each flux barrier 40 has hollow portions on either side of the magnets 24, which can be used as channels for a cooling fluid to cool the magnets 24.

[0032] The four types of flux barriers 40a-40d are arranged in a V-shaped or U-shaped V-shaped pattern Pv that expands toward the outer periphery of the rotor core 22. Multiple sets (eight in this embodiment) of these V-shaped patterns Pv are arranged at equal angular intervals around the centerline O of the rotor core 22. The V-shaped patterns Pv are symmetrical about the d-axis passing through the centerline O. The flux barrier 40a with magnet A and the flux barrier 40b with magnet a are symmetrical, while the flux barrier 40c with magnets B and b and the flux barrier 40d with magnets C and c are symmetrical. In other words, the V-shaped pattern Pv of this embodiment has a double structure, with a pair of flux barriers 40a and 40b arranged on the outer periphery of the pair of flux barriers 40c and 40d. Furthermore, even the flux barrier 40 c provided with the magnets B and b and the flux barrier 40 d provided with the magnets C and c can be regarded as a V-shaped arrangement pattern Pv that expands toward the outer peripheral side of the rotor core 22 .

[0033] In this rotor 12, the midline between two circumferentially adjacent pairs of V-shaped patterns Pv forms the q-axis. When used as the rotating electrical machine 10, the magnetic flux (stator flux) of the rotating magnetic field formed by the stator 14 passes through the rotor 12 along this q-axis. In this case, the pair of flux barriers 40c and 40d located closest to the q-axis are symmetrically arranged on either side of the circumference, forming an inverted V-shape that expands toward the inner circumference of the rotor core 22. Furthermore, the rectangular-shaped magnets B and C, and b and c, secured to the flux barriers 40c and 40d, are also arranged symmetrically on either side of the circumference, with the long sides of the rectangular cross-section forming an inverted V-shape. The pair of magnets b and c located on the inner circumference of the rotor core 22 are referred to as first magnets, and the pair of magnets B and C located on the outer circumference are referred to as second magnets. In the following description, they will be referred to as first magnets b and c and second magnets B and C, as appropriate. The apex S1 of the inverted V-shape of the first magnets b and c on the inner circumference side (see Figure 3 ) is larger than the angle of the vertex S2 of the inverted V-shape of the outer peripheral second magnets B and C. The angle of the vertex S1 is greater than 90°, and is approximately 120° in this embodiment. Figure 2 The solid arrows fs in FIG. 1 are examples of magnetic flux lines of the stator magnetic flux passing along the q-axis. The shortest distance between the flux barriers 40c and 40d provided on either side of the q-axis is the q-axis salient pole width Wq1, and the stator magnetic flux passes within this q-axis salient pole width Wq1. The directions of the magnetic flux lines fs of the stator magnetic flux may also be opposite.

[0034] Meanwhile, cooling holes 42 are provided axially through the rotor core 22, on the q-axis and on the inner circumference of the rotor core 22 relative to the flux barriers 40c and 40d. These cooling holes 42 are holes used to cool the magnets 24, particularly the pair of first magnets b and c located closest to the innermost side of the rotor core 22, and allow cooling fluid to flow through them. The cooling holes 42 are symmetrically arranged on either side of the circumference about the q-axis and have a curved shape that convexly projects toward the outer circumference of the rotor core 22. These cooling holes 42 are located closer to the inner circumference of the rotor core 22 than the pair of first magnets b and c located closest to the innermost side of the rotor core 22 in the q-axis direction. These cooling holes 42 correspond to cavities.

[0035] The polarities of the NS of the first magnets b and c and the second magnets B and C are opposite to each other, and magnet fluxes are formed between the facing portions of the first magnets b and c and between the facing portions of the second magnets B and C, respectively. Figure 2The dashed arrows fr1 to fr4 illustrate the magnetic flux lines between the first magnets b and c and the second magnets B and C. The region between the magnetic flux line fr1 connecting the inner circumferential ends of the long sides of the first magnets b and c, which face each other across the q-axis, and the magnetic flux line fr2 connecting the outer circumferential ends is the region through which the magnetic flux passes between the first magnets b and c. Furthermore, the region between the magnetic flux line fr3 connecting the inner circumferential ends of the long sides of the second magnets B and C, which face each other across the q-axis, and the magnetic flux line fr4 connecting the outer circumferential ends is the region through which the magnetic flux passes between the second magnets B and C. The directions of the magnetic flux lines fr1 to fr4 may be opposite, and the paths of the magnetic flux lines fr1 to fr4 vary depending on the orientation, magnetic mass (magnetic moment) of the magnets b, c, B, and C, the magnetic permeability of the rotor core 22, and other factors.

[0036] Figure 3 The figure further magnifies the pair of flux barriers 40c and 40d on both sides of the q-axis and the vicinity of the cooling hole 42. Figure 3 In the figure, the arc centered at the vertex S2 of the inverted V-shaped portion of the pair of second magnets B and C arranged on the outer circumference of the rotor core 22 and passing through the inner circumference corners bi and ci of the pair of first magnets b and c arranged on the inner circumference of the rotor core 22 is set as the boundary imaginary line Lm of the magnetic flux between the first magnets b and c, i.e., the magnet magnetic flux. Furthermore, the cooling hole 42 is provided on the inner circumference of the rotor core 22 relative to the boundary imaginary line Lm, thereby preventing the cooling hole 42 from obstructing the passage of the magnet magnetic flux and preventing a decrease in the motor torque or motor efficiency caused by the cooling hole 42. The boundary imaginary line Lm is approximately Figure 2 By positioning the cooling holes 42 closer to the inner circumference of the rotor core 22 than the imaginary boundary line Lm, the cooling holes 42 are effectively prevented from obstructing the passage of the magnet magnetic flux. Although the imaginary boundary line Lm varies depending on the position of the vertex S2, that is, the posture of the second magnets B and C, there is a possibility that the imaginary boundary line Lm may be positioned closer to the outer circumference of the rotor core 22 than the magnetic flux line fr1, thereby obstructing the passage of the magnetic flux by the cooling holes 42, at least because it is positioned closer to the inner circumference of the rotor core 22 than the straight line connecting the inner circumference corners bi and ci of the pair of first magnets b and c, the degree of obstruction is reduced compared to a case where the cooling holes 42 are positioned on the straight line connecting the inner circumference corners bi and ci of the pair of first magnets b and c, as in Patent Document 1.

[0037] In addition, Figure 3In the figure, the line segment connecting the shortest distance between the cooling hole 42 and the first magnet b is defined as the shortest line segment Ls. In this embodiment, since the long side of the rectangular cross section of the first magnet b is inclined so as to intersect the q axis at approximately 60 degrees, and the cooling hole 42 is provided so as to include a position perpendicular to the long side of the rectangular cross section, the image is obtained according to the embodiment. Figure 3 As is clear, a shortest line segment Ls is defined between the long side and the cooling hole 42. Furthermore, on this shortest line segment Ls, there is an intersection point P with the aforementioned imaginary boundary line Lm. Therefore, if the length of the shortest line segment Ls is set as the shortest distance Wb, the length from the intersection point P to the first magnet b is set as the d-axis magnetic flux passage width Wd, and the length from the intersection point P to the cooling hole 42 is set as the q-axis magnetic flux passage width Wq2, the shortest distance Wb can be expressed by the following equation (1). The d-axis magnetic flux passage width Wd is mainly the area through which the magnet magnetic flux between the first magnets b and c passes, and the q-axis magnetic flux passage width Wq2 is mainly the area through which the stator magnetic flux passes. Thus, since there is an intersection point P with the imaginary boundary line Lm within the shortest line segment Ls, and there is a q-axis magnetic flux passage width Wq2 between the intersection point P and the cooling hole 42, the stator magnetic flux can appropriately pass between the first magnet b and the cooling hole 42.

[0038] Wb=Wd+Wq2···(1)

[0039] The cooling holes 42 are also arranged so that the q-axis magnetic flux passage width Wq2 is smaller than the q-axis salient pole width Wq1. In this embodiment, as shown in the following equation (2), they are arranged so that they are at least 1 / 2 of the q-axis salient pole width Wq1. That is, by making the q-axis magnetic flux passage width Wq2 smaller than the q-axis salient pole width Wq1, the cooling holes 42 are positioned further away from the first magnet b than necessary, thereby preventing any loss of cooling performance. Furthermore, by placing the cooling holes 42 as close to the first magnet b as possible, it is possible to achieve adequate cooling performance for the first magnet b. Furthermore, by setting the q-axis magnetic flux passage width Wq2 to at least 1 / 2 of the q-axis salient pole width Wq1, a suitable cross-section for the passage of the magnet magnetic flux and the stator magnetic flux is ensured between the first magnet b and the cooling holes 42. This appropriately prevents performance degradation, such as the cooling holes 42 obstructing the passage of the magnet magnetic flux or the stator magnetic flux, which reduces magnetic flux and thus reduces motor torque, or increases iron loss due to increased magnetic flux density and thus reduces motor efficiency. That is, since the stator magnetic flux passing through the q-axis salient pole width Wq1 is split in two directions by the cooling holes 42, by setting the q-axis magnetic flux passage width Wq2 to be at least 1 / 2 of the q-axis salient pole width Wq1, the stator magnetic flux passage cross-section can be appropriately ensured. The position and shape of the cooling holes 42 are specified to satisfy equation (2).

[0040] (1 / 2)Wq1≤Wq2<Wq1···(2)

[0041] The magnetic flux lines fs of the stator magnetic flux are formed by the presence of the cooling holes 42. Figure 2 As shown, the first magnet b and the first magnet c are divided on both sides of the cooling hole 42 and pass between the cooling hole 42 and the first magnets b and c. In this case, since the first magnets b and c and the cooling hole 42 are symmetrically arranged with respect to the q-axis, the relationship between the first magnet c and the cooling hole 42 on the opposite side is the same as the relationship between the first magnet b and the cooling hole 42 described above, and the same operational effects can be achieved.

[0042] Thus, according to the rotor 12 of the rotating electric machine 10 of this embodiment, the arc centered on the vertex S2 and passing through the inner circumferential corners bi and ci of the pair of first magnets b and c is defined as the imaginary boundary line Lm, and the cooling holes 42 are located closer to the inner circumference of the rotor core 22 than the imaginary boundary line Lm. This prevents the cooling holes 42 from obstructing the passage of magnet magnetic flux, thereby suppressing a decrease in motor torque and motor efficiency caused by the cooling holes 42. Furthermore, because the q-axis magnetic flux passage width Wq2 on the cooling hole 42 side relative to the intersection point P with the imaginary boundary line Lm on the shortest line segment Ls between the first magnets b and c and the cooling holes 42 is smaller than the q-axis salient pole width Wq1, the cooling holes 42 are located as close to the first magnets b and c as possible while ensuring a sufficient passage cross-section for the magnet magnetic flux and the stator magnetic flux. This ensures that the cooling holes 42 provide adequate cooling performance for the first magnets b and c, thereby suppressing a decrease in motor torque due to overheating and demagnetization. Since the stator magnetic flux passing through the q-axis salient pole width Wq1 is divided into two directions by the cooling hole 42 , even if the q-axis magnetic flux passing width Wq2 is smaller than the q-axis salient pole width Wq1 , the stator magnetic flux passing cross section can be ensured.

[0043] Furthermore, in this embodiment, the imaginary boundary line Lm is defined by the arc extending from the vertex S2 of the inverted V-shaped second magnets B and C, which are positioned on the outer circumference of the rotor core 22 relative to the first magnets b and c, and passing through the inner circumferential corners bi and ci of the first magnets b and c. This imaginary boundary line Lm approximates the boundary line of the magnet flux of the first magnets b and c, that is, the magnetic flux line fr1. This effectively prevents the cooling holes 42 from obstructing the passage of the magnet flux. Furthermore, while ensuring sufficient cross-sections for the passage of the magnet flux and the stator flux, the cooling holes 42 are positioned as close to the first magnets b and c as possible, ensuring optimal cooling performance for the first magnets b and c.

[0044] In addition, since multiple flux barriers 40 are grouped as a V-shaped or U-shaped V-shaped configuration pattern Pv, ​​and multiple groups are arranged around the center line O of the rotor core 22, and the middle line of two groups of V-shaped configuration patterns Pv adjacent to each other in the circumferential direction is the q-axis, and a pair of flux barriers 40c and 40d located on both sides closest to the q-axis are arranged to form an inverted V-shaped posture, the present invention is preferably applied.

[0045] Furthermore, since the q-axis magnetic flux passage width Wq2 is smaller than the q-axis salient pole width Wq1 and is at least 1 / 2 of the q-axis salient pole width Wq1, cooling holes 42 can be provided near the first magnets b and c. This ensures cooling performance for the first magnets b and c while also appropriately ensuring a sufficient cross-section for the passage of the magnet magnetic flux and the stator magnetic flux. Since the stator magnetic flux passing through the q-axis salient pole width Wq1 is split into two directions by the cooling holes 42, by making the q-axis magnetic flux passage width Wq2 smaller than the q-axis salient pole width Wq1 and at least 1 / 2 of the q-axis salient pole width Wq1, an adequate cross-section for the passage of the stator magnetic flux can be ensured.

[0046] In the above embodiment, the arc having the vertex S2 of the inverted V shape of the second magnets B and C disposed on the outer peripheral side of the rotor core 22 relative to the first magnets b and c as the center and passing through the inner peripheral corners bi and ci of the first magnets b and c is set as the boundary imaginary line Lm. However, Figure 4 As shown, the straight line connecting the inner circumferential corners bi and ci of a pair of first magnets b and c disposed on the innermost circumferential side of the rotor core 22 can also be set as the boundary imaginary line Lm. Hereinafter, the boundary imaginary line Lm will be referred to as the boundary imaginary line (straight line) Lm. Then, by arranging the cooling hole 42 closer to the inner circumference of the rotor core 22 than the boundary imaginary line (straight line) Lm, it is possible to prevent the cooling hole 42 from obstructing the passage of the magnet magnetic flux, thereby suppressing the decrease in motor torque or motor efficiency caused by the cooling hole 42. Although Figure 2 The magnetic lines of force fr1 pass through the inner circumference of the rotor core 22 relative to the boundary imaginary line (straight line) Lm, so there is a possibility of being blocked by the cooling hole 42. However, compared with the case where the cooling hole 42 is provided on the straight line connecting the inner circumference corners bi and ci of a pair of first magnets b and c as in the patent document 1, the degree of obstruction is reduced.

[0047] Furthermore, on the shortest line segment Ls between the first magnets b and c and the cooling hole 42, the position and shape of the cooling hole 42 are determined so that the q-axis magnetic flux passage width Wq2 on the cooling hole 42 side relative to the intersection point P with the aforementioned imaginary boundary line (straight line) Lm is smaller than the q-axis salient pole width Wq1. This ensures that the cooling hole 42 is positioned as close to the first magnets b and c as possible while ensuring sufficient passage cross-sections for the magnet magnetic flux and stator magnetic flux. This ensures optimal cooling performance for the first magnets b and c through the cooling hole 42, thereby suppressing a decrease in motor torque caused by overheating and demagnetization.

[0048] Furthermore, by specifying the position and shape of the cooling hole 42 so as to satisfy equation (2), specifically, so that the q-axis magnetic flux passage width Wq2 is smaller than the q-axis salient pole width Wq1 and is at least 1 / 2 of the q-axis salient pole width Wq1, the cooling hole 42 can be positioned close to the first magnets b and c, thereby ensuring cooling performance for the first magnets b and c while also appropriately ensuring a sufficient passage cross-section for the magnet magnetic flux and the stator magnetic flux. That is, since the stator magnetic flux passing through the q-axis salient pole width Wq1 is split into two directions by the cooling hole 42, the stator magnetic flux passage cross-section can be appropriately ensured by setting the q-axis magnetic flux passage width Wq2 smaller than the q-axis salient pole width Wq1 and at least 1 / 2 of the q-axis salient pole width Wq1.

[0049] Although the embodiment of the present invention has been described in detail above with reference to the drawings, this is ultimately only one embodiment, and the present invention can be implemented in various ways with various modifications and improvements added based on the knowledge of those skilled in the art.

[0050] Explanation of symbols

[0051] 10: Rotating electric machine; 12: Rotor for rotating electric machine; 20: Rotor shaft; 22: Rotor core; 24, A, a, B, b, C, c: Magnet; b, c: Magnet (first magnet); B, C: Magnet (second magnet); 40a, 40b, 40c, 40d: Flux barrier; 40c, 40d: A pair of flux barriers; 42: Cooling hole (cavity); O: Center line; q: q-axis; Pv: V-shaped configuration pattern; fs: Magnetic lines of stator flux (stator flux); fr1, fr2, fr3, fr4: Magnetic lines of magnet flux (magnet flux); S1, S2: Vertex; Lm: Imaginary boundary line; Ls: Shortest line segment; P: Intersection point; Wq1: q-axis salient pole width; Wq2: q-axis flux passage width.

Claims

1. A rotor (12) for a rotating electric machine, comprising a cylindrical rotor core (22), wherein a pair of flux barriers (40c, 40d) having magnet mounting portions are symmetrically arranged on both sides of a q-axis in the rotor core (22), wherein magnets are arranged in the magnet mounting portions, a cavity (42) is provided on the q-axis, and a stator magnetic flux (fs) passes along the q-axis. The rotor (12) for a rotating electric machine is characterized in that: In the pair of flux barriers (40c, 40d), a pair of first magnets (b, c) are provided as the magnets in a symmetrical manner with respect to the q-axis, and the first magnets (b, c) have a rectangular cross-section perpendicular to the center line (O) of the rotor shaft (20) and are arranged in an inverted V-shape that expands toward the inner circumference of the rotor core (22). On the other hand, the shortest distance between the pair of flux barriers (40c, 40d) provided on both sides of the q-axis is set to be the q-axis salient pole width Wq1 through which the stator flux (fs) passes. A straight line connecting the inner circumferential corners (bi, ci) of the pair of first magnets (b, c) located on the innermost circumferential side of the rotor core (22), or an arc protruding toward the inner circumference of the rotor core (22) relative to the straight line, is set as a boundary imaginary line Lm of the magnetic flux of the first magnets (b, c), i.e., the magnet magnetic flux. The cavity (42) is provided on the inner circumference side of the rotor core (22) relative to the imaginary boundary line Lm. Furthermore, when the line segment connecting the first magnet (b, c) and the cavity portion (42) at the shortest distance is set as the shortest line segment Ls, and the length on the side of the cavity portion (42) compared to the intersection P with the boundary imaginary line Lm on the shortest line segment Ls is set as the q-axis magnetic flux passing width Wq2, the q-axis magnetic flux passing width Wq2 is smaller than the q-axis salient pole width Wq1.

2. The rotor (12) for a rotating electrical machine according to claim 1, characterized in that In the pair of flux barriers (40c, 40d), a pair of second magnets (B, C) are provided as the magnets on the outer peripheral side of the rotor core (22) relative to the first magnets (b, c) in a symmetrical manner with respect to the q-axis, and the second magnets (B, C) have a rectangular cross-section perpendicular to the center line (O) of the rotor shaft (20) and are arranged in an inverted V-shape that expands toward the inner peripheral side of the rotor core (22). The virtual boundary line Lm is an arc having the vertex S2 of the inverted V-shape of the second magnet (B, C) as its center and passing through the inner circumferential corners (bi, ci) of the pair of first magnets (b, c).

3. The rotor (12) for a rotating electrical machine according to claim 1, characterized in that The virtual boundary line Lm is a straight line connecting the inner peripheral corner portions (bi, ci) of the pair of first magnets (b, c).

4. The rotor (12) for a rotating electrical machine according to any one of claims 1 to 3, characterized in that: In the rotor core (22), at least two magnetic flux barriers (40a, 40b, 40c, 40d) are arranged in a V-shaped or U-shaped V-shaped pattern (Pv) in a manner that expands toward the outer peripheral side as a group, and a plurality of groups are arranged at equal angular intervals around the center line (O) of the rotor shaft (20). The middle line of two groups of V-shaped configuration patterns (Pv) adjacent in the circumferential direction is the q-axis, and a pair of flux barriers (40c, 40d) located on both sides closest to the q-axis are the pair of flux barriers (40c, 40d) symmetrically arranged on both sides in the circumferential direction with the q-axis sandwiched therebetween.

5. The rotor (12) for a rotating electrical machine according to any one of claims 1 to 4, characterized in that: The q-axis magnetic flux passage width Wq2 is smaller than the q-axis salient pole width Wq1 and is greater than 1 / 2 of the q-axis salient pole width Wq1.

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