Embedded magnet rotor and rotating electric machine

Abstract

The present invention provides an embedded magnet type rotor that suppresses short circuits of magnetic flux in the rotor's magnetic poles, increases reluctance torque, and suppresses the effects of stress generated in the rotor core. [Solution] In an embedded magnet rotor having multiple magnetic poles formed in the circumferential direction of an iron core, each magnetic pole comprises a magnet arranged on the iron core in a V-shaped pattern with increasing spacing toward the outer circumference of the rotor, and a pair of flux barriers formed at the inner circumferential end of the magnet on the iron core. The flux barriers are formed to protrude further inward than the inner circumferential end of the magnet, and have portions that protrude toward the d-axis of the magnetic pole and portions that protrude toward the q-axis of the magnetic pole.

Description

Technical Field

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[0001] The present invention relates to an embedded magnet rotor and a rotating electrical machine.

Background Art

[0002] Conventionally, in order to achieve high torque density and high output density of a rotating electrical machine, various types of embedded magnet rotors have been proposed in which a plurality of magnets are arranged in multiple layers on one pole and a flux barrier is provided at the position of the magnet end. For example, Patent Document 1 proposes a rotor structure in which the shape of the flux barrier provided on the outer peripheral side of the rotor is within a predetermined range, and vibration and noise can be suppressed by reducing torque ripple.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] This type of embedded magnet rotor is required to be able to cope with stress due to centrifugal force associated with high rotation and stress generated during press-fitting (or shrink-fitting) of the shaft. On the other hand, if the bridge width of the iron core formed between the magnets on the inner peripheral side is increased to relieve the above stress, there is a problem that the magnetic flux short-circuited at the magnetic poles of the rotor increases and the torque of the rotating electrical machine decreases. In addition, in a rotating electrical machine to which this type of embedded magnet rotor is applied, it is also required to increase reluctance torque to improve efficiency. Note that there was still room for improvement in the shape of the flux barrier provided on the inner peripheral side of the rotor in Patent Document 1.

[0005] The present invention has been made in view of the above circumstances, and aims to provide an embedded magnet type rotor that can increase reluctance torque while suppressing short circuits of magnetic flux in the rotor's magnetic poles, and can also suppress the influence of stress generated in the rotor core. [Means for solving the problem]

[0006] One embodiment is an embedded magnet type rotor in which multiple magnetic poles are formed in the circumferential direction of an iron core. Each magnetic pole comprises a magnet arranged on the iron core in a V-shaped pattern with increasing spacing toward the outer circumference of the rotor, and a pair of flux barriers formed at the inner circumferential end of the magnet on the iron core. The flux barriers are formed to protrude further inward than the inner circumferential end of the magnet, and have portions that protrude toward the d-axis of the magnetic pole and portions that protrude toward the q-axis of the magnetic pole. The flux barrier has a portion that protrudes inward from the inner circumference end of the magnet and a portion that protrudes outward from the inner circumference end of the magnet, at a position on the d-axis side of the inner circumference end of the magnet. When the direction along the d-axis is taken as the first direction and the direction perpendicular to the d-axis is taken as the second direction, the portion of the flux barrier that protrudes toward the q-axis side of the magnetic pole extends in the second direction. The flux barrier is formed such that the width in the first direction at the portion protruding toward the q-axis side is smaller than the width in the second direction at the portion protruding toward the d-axis side.

[0007] One aspect described above Iron The core may have a bridge portion extending radially along the d-axis between a pair of flux barriers. Furthermore, the bridge portion may be formed with a wider outer width than the inner width.

[0008] One aspect described above In, The portion of the Lux barrier that protrudes towards the q-axis may have a shape that includes a protrusion that extends toward the outer circumference of the iron core. The above-mentioned protrusion may be formed at the q-axis end of the flux barrier, and the protrusion and the q-axis end of the flux barrier may have a linear portion along the q-axis. The above-mentioned protrusion may be formed in a shape that protrudes further outward from the iron core than from the inner end of the magnet.

[0009] The embedded magnet rotor in one embodiment described above may further include a shaft extending along the axis of rotation of the iron core. The flux barrier may be arranged in a ring around the iron core along the outer circumference of the shaft, with portions that protrude inward beyond the inner circumference ends of the magnets.

[0010] In one embodiment of the above, magnets may be arranged in multiple layers from the outer circumference to the inner circumference of the magnetic pole, and a pair of flux barriers may be formed at the inner circumference ends of the magnets arranged on the inner circumference. Furthermore, another embodiment of the rotating electric machine comprises a stator and an embedded magnet type rotor as described in one embodiment above. [Effects of the Invention]

[0011] According to one embodiment, it is possible to provide an embedded magnet type rotor that can increase reluctance torque while suppressing short circuits of magnetic flux in the rotor's magnetic poles, and can also suppress the influence of stress generated in the rotor core. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view of the rotating electric machine according to the first embodiment. [Figure 2] This figure shows an example of the configuration of a rotor for one magnetic pole in the first embodiment. [Figure 3] This is a magnified view of a portion of Figure 2. [Figure 4] This figure shows an example of the configuration of a rotor for one magnetic pole in the second embodiment. [Figure 5] This is a magnified view of a portion of Figure 4. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, for the sake of clarity, structures and elements other than the main parts of the present invention will be simplified or omitted in the description. Also, the same elements will be denoted by the same reference numerals in the drawings. Note that the shapes and dimensions of each element shown in the drawings are schematic representations and do not represent the actual shapes and dimensions.

[0014] <First Embodiment> FIG. 1 is a cross-sectional view showing a cross-section in a direction orthogonal to the rotation axis Ax of the rotating electrical machine according to the first embodiment. In the following description, the direction parallel to the extension direction of the rotation axis Ax is referred to as the axial direction, the circumferential direction centered on the rotation axis Ax is simply referred to as the circumferential direction, and the radial direction centered on the rotation axis Ax is simply referred to as the radial direction.

[0015] The rotating electrical machine 1 shown in FIG. 1 is an inner rotor type motor and includes a rotor 2 which is an example of an embedded magnet type rotor, and a cylindrical stator 3 disposed on the outer periphery of the rotor 2. In FIG. 1, the extension direction of the rotation axis Ax of the rotating electrical machine 1 is perpendicular to the plane of the paper.

[0016] The stator 3 is disposed on the outer periphery of the rotor 2 with an air gap therebetween. In the rotating electrical machine 1, by sequentially switching the magnetic field of the stator 3 by controlling the current of the coil described later, the rotor 2 rotates about the rotation axis Ax due to the attractive force or repulsive force with the magnetic field of the rotor 2.

[0017] The stator 3 houses the rotor 2 in a central space portion centered on the rotation axis Ax. On the inner peripheral side of the stator 3, a plurality of teeth 3a protruding radially inward toward the rotation axis Ax are provided at equal intervals in the circumferential direction. Slots 3b are formed between adjacent teeth 3a. Coils (not shown) are mounted in the slots 3b of the stator 3 along the outer periphery of the rotor 2.

[0018] The rotor 2 has a core 4, a shaft 5, and a plurality of permanent magnets 6, 7. The core 4 of the rotor 2 is, for example, a cylindrical member formed by laminating punched silicon steel sheets in the axial direction. An insulating adhesive is interposed between the individual silicon steel sheets constituting the core 4, and the individual silicon steel sheets are in an insulated state from each other. And a shaft 5 extending along the rotation axis Ax is fitted into the central portion of the core 4. In the rotating electrical machine 1, the shaft 5 is rotatably supported by bearings (not shown).

[0019] The rotor 2 of the first embodiment is an 8-pole rotor, and a plurality of permanent magnets 6, 7 are arranged in a predetermined arrangement on the iron core 4 of the rotor 2 so that eight magnetic poles are formed at equal intervals along the circumferential direction. In the rotor 2, the permanent magnets 6, 7 are arranged such that adjacent magnetic poles in the circumferential direction have opposite polarities.

[0020] Figure 2 shows an example of the configuration of a rotor 2 for one magnetic pole in the first embodiment. Here, for one magnetic pole of rotor 2, the axis connecting the axis of rotor 2 (rotation axis Ax) in Figure 1 and the magnetic pole center that generates the magnetic torque becomes the d-axis of the dq-axis coordinate system. Furthermore, the axis perpendicular to the above d-axis in terms of electrical angle becomes the q-axis of the dq-axis coordinate system.

[0021] The iron core 4 of the rotor 2 has a structure in which permanent magnets are arranged in two layers on the outer and inner sides of one magnetic pole. Hereinafter, the arrangement of a pair of permanent magnets 6 located on the outer side of one magnetic pole will be referred to as the first layer, and the arrangement of a pair of permanent magnets 7 having a portion located on the inner side of the first layer will be referred to as the second layer.

[0022] The first layer consists of a pair of first magnet holes 11 that penetrate the iron core 4 in the axial direction, and a pair of permanent magnets 6 fitted into the first magnet holes 11. The first magnet holes 11 are arranged symmetrically with respect to the d-axis of the magnetic poles and open into the iron core 4 in a tapered pattern, with the spacing between them increasing as they approach the outer circumference of the iron core 4.

[0023] Each permanent magnet 6 has a rectangular cross-sectional shape intersecting the axial direction, and is magnetized in a direction perpendicular to its longer side in a plane perpendicular to the rotation axis Ax. When the permanent magnets 6 are inserted into the first magnet holes 11, the permanent magnets 6 are arranged in a V-shaped pattern in the first layer on the outer circumference of the iron core 4 at one magnetic pole.

[0024] The second layer consists of a pair of second magnet holes 12 that penetrate the iron core 4 in the axial direction, and a pair of permanent magnets 7 fitted into each of the second magnet holes 12. The second magnet holes 12 are arranged symmetrically with respect to the d-axis of the magnetic poles and open into the iron core 4 in a tapered pattern, with the spacing between them increasing as they approach the outer circumference of the iron core 4.

[0025] Furthermore, the second magnet hole 12 is formed on the inner circumference side than the first magnet hole 11. The longitudinal length of the second magnet hole 12 is longer than the longitudinal length of the first magnet hole 11. Also, the inclination in the direction perpendicular to the d-axis in Figure 2 (left-right direction in Figure 2) is greater than that of the first magnet hole 11. As a result, the second magnet hole 12 of the second layer has a pattern that covers the first magnet hole 11 of the first layer from the inner circumference side.

[0026] Each permanent magnet 7 has a rectangular cross-sectional shape intersecting the axial direction, and is magnetized in a direction perpendicular to its longer side in a plane perpendicular to the rotation axis Ax. Furthermore, the longitudinal length of the permanent magnets 7 in the second layer is longer than the longitudinal length of the permanent magnets 6 in the first layer, similar to the second magnet hole 12. When the permanent magnets 7 are inserted into the second magnet hole 12, the permanent magnets 7 are arranged in a V-shaped pattern in the second layer on the inner circumference side of the iron core 4 at one magnetic pole.

[0027] Furthermore, each permanent magnet 6 and 7 in the same magnetic pole has its magnetic pole surface facing the outer periphery aligned to have the same magnetic polarity (either south or north pole).

[0028] Flux barriers 13 are formed at the outer circumference end of the first magnet hole 11, and flux barriers 14 are formed at the inner circumference end of the first magnet hole 11. Both flux barriers 13 and 14 are holes (spaces) that communicate with the first magnet hole 11 and penetrate the iron core 4 in the axial direction. Similarly, flux barriers 15 are formed at the outer circumference end of the second magnet hole 12, and flux barriers 16 are formed at the inner circumference end of the second magnet hole 12. Both flux barriers 15 and 16 are holes (spaces) that communicate with the second magnet hole 12 and penetrate the iron core 4 in the axial direction.

[0029] Flux barriers 13, 14, 15, and 16 have extremely low magnetic permeability compared to the iron core 4, making it difficult for magnetic flux to pass through, and therefore each functions as a magnetic shielding element.

[0030] Between the d-axis and q-axis on the outer circumference of the rotor 2, flux barriers 13 are formed at the outer circumference ends 6a of the first layer permanent magnets 6, and flux barriers 15 are formed at the outer circumference ends 7a of the second layer permanent magnets 7, thereby suppressing harmonic components included in the magnetic flux density waveform. As a result, the distribution of magnetic flux density generated on the outer circumference of the rotor 2 by the permanent magnets 6 and 7 changes, and the magnetic flux density distribution at both ends in the circumferential direction of the magnetic poles approaches a sine wave. Consequently, electromagnetic excitation forces such as torque ripple are effectively reduced in the rotor 2.

[0031] Furthermore, the formation of flux barriers 14 on the inner circumference ends 6b of the first layer permanent magnets 6 narrows the width of the d-axis side core 4 sandwiched between the pair of permanent magnets 6 and the flux barriers 14 in the first layer. This suppresses the short-circuiting magnetic flux in the first layer permanent magnets 6, improving the torque of the rotating electric machine 1. As shown in the example in Figure 2, when the cross-sectional shape of the permanent magnets 6 and 7 is rectangular, the inner circumference ends 6b and 7b are both flat and have an end (corner) on the d-axis side and an end (corner) on the q-axis side, respectively.

[0032] Here, the flux barriers 16 formed on the inner circumference end 7b of the second layer permanent magnet 7 are formed in the following shape as an example.

[0033] Figure 3 is a partially enlarged view of Figure 2. The overall shape of the flux barrier 16 is a roughly triangular shape with rounded corners. The flux barrier 16 has an inner wall portion 21, a radially extending portion 22, and a hypotenuse portion 23.

[0034] The inner wall portion 21 of the flux barrier 16 faces the shaft 5 and extends circumferentially from the q-axis side to the d-axis side. The radially extending portion 22 of the flux barrier 16 extends radially along the d-axis. The inner circumference of the radially extending portion 22 is connected to the d-axis side of the inner wall portion 21. In addition, the slanted edge portion 23 of the flux barrier 16 extends inclined toward the q-axis from the outer circumference side to the inner circumference side of the iron core 4. The outer circumference of the slanted edge portion 23 is connected to the outer circumference side of the radially extending portion 22, and the inner circumference of the slanted edge portion 23 is connected to the q-axis side of the inner wall portion 21.

[0035] The flux barrier 16 is connected to the second magnet hole 12 in the middle of the slanted edge portion 23. As a result, the flux barrier 16 has a portion that protrudes inward from the inner end portion 7b of the permanent magnet 7 and a portion that protrudes outward from the inner end portion 7b of the permanent magnet 7.

[0036] The portion of the flux barrier 16 that protrudes inward faces the entire inner wall portion 21, the region in the radially extending portion 22 that is located further inward than the inner end 7b of the permanent magnet 7, and the region in the slanted edge portion 23 that is located further inward than the inner end 7b of the permanent magnet 7. The portion of the flux barrier 16 that protrudes outward faces the region in the radially extending portion 22 that is located further outward than the inner end 7b of the permanent magnet 7, and the region in the slanted edge portion 23 that is located further outward than the inner end 7b of the permanent magnet 7.

[0037] Furthermore, the flux barrier 16 has a portion that protrudes q-axis further than the inner circumference end 7b of the permanent magnet 7, and a portion that protrudes d-axis further than the inner circumference end 7b of the permanent magnet 7. In the example shown in Figure 2, the flux barrier 16 has a portion that protrudes q-axis further than the q-axis end of the inner circumference end 7b, and a portion that protrudes d-axis further than the d-axis end of the inner circumference end 7b. Note that the portion of the flux barrier 16 that protrudes q-axis further than the dashed line (shown as a dotted line in Figure 3) extended along the q-axis side surface of the permanent magnet 7, as shown in Figure 3.

[0038] The portion of the flux barrier 16 that protrudes toward the q-axis faces the region on the hypotenuse 23 that is located on the q-axis side of the inner circumference end 7b of the permanent magnet 7, and the region on the inner wall 21 that is located on the q-axis side of the inner circumference end 7b of the permanent magnet 7. The portion of the flux barrier 16 that protrudes toward the d-axis faces the entire radially extending portion 22, the region on the hypotenuse 23 that is located on the d-axis side of the inner circumference end 7b of the permanent magnet 7, and the region on the inner wall 21 that is located on the d-axis side of the inner circumference end 7b of the permanent magnet 7.

[0039] Furthermore, at one magnetic pole, a pair of flux barriers 16 are formed on the iron core 4 in a symmetrical pattern such that the radially extending portions 22 face each other around the d-axis. This forms a bridge portion 24 extending radially along the d-axis between the pair of flux barriers 16. The bridge portion 24 is formed such that the width L2 on the radially outer side is wider than the width L1 on the radially inner side (L1 <L2)。

[0040] As described above, the flux barrier 16 formed at the inner circumference end 7b of the second layer permanent magnet 7 has a portion that protrudes toward the d-axis, thus reducing the width from the flux barrier 16 to the d-axis in the iron core 4. Furthermore, since the flux barrier 16 has a portion that protrudes toward the q-axis, the width from the flux barrier 16 to the q-axis in the iron core 4 is also reduced. As a result, in the rotor 2 of the first embodiment, short-circuiting of the magnetic flux of the permanent magnet 7 is suppressed at the inner circumference end 7b of the permanent magnet 7.

[0041] Furthermore, since the flux barrier 16 has a portion that protrudes toward the d-axis, the magnetic field in the d-axis is reduced by the flux barrier 16 in the rotor 2. As a result, the rotor 2 of the first embodiment can increase the reluctance torque.

[0042] Furthermore, the portion of the flux barrier 16 that protrudes inward from the inner end 7b of the permanent magnet 7 serves to alleviate the stress generated in the iron core 4 when the shaft 5 is fixed to the iron core 4 of the rotor 2 by shrink fitting or press fitting. As shown in Figure 1, in the iron core 4, multiple flux barriers 16 are arranged in an annular pattern on the outer circumference side of the shaft 5 such that each inner wall portion 21 faces the shaft 5. When the shaft 5 is fixed, the strain in the iron core 4 is absorbed by the gaps in the flux barriers 16, so that stress concentration in the portion of the iron core 4 near the shaft 5 can be reduced, and the mechanical strength of the rotor 2 can be improved.

[0043] Furthermore, the flux barrier 16 has portions that protrude inward and outward on the d-axis side. This increases the radial length of the bridge portion formed between the pair of flux barriers 16, making it easier to suppress short circuits of the magnetic flux of the permanent magnet 7 and also increasing the reluctance torque. Furthermore, by making the outer width L2 of the bridge section 24 wider than the inner width L1, it is possible to increase the reluctance torque while improving the mechanical strength of the bridge section 24 against centrifugal force.

[0044] Furthermore, since the flux barrier 16 has a relatively large opening area and penetrates the rotor 2 axially, it can also be used as a through-hole for inserting assembly bolts during the assembly of the rotor 2. In this way, the flux barrier 16 can also contribute to improving the ease of assembly of the rotor 2.

[0045] <Second Embodiment> Figure 4 shows an example of the configuration of a rotor 2A for one magnetic pole in the second embodiment. In describing the rotor 2A of the second embodiment, elements common to the rotor 2 of the first embodiment are denoted by the same reference numerals, and redundant explanations are omitted as appropriate.

[0046] The rotor 2A of the second embodiment is a modified version of the rotor 2 of the first embodiment. In the second embodiment, the shape of the flux barrier 16A formed on the inner circumference end 7b of the second layer permanent magnet 7 differs from that of the flux barrier 16 of the first embodiment. Also, the outer diameter of the rotor 2A of the second embodiment is the same as the outer diameter of the rotor 2 of the first embodiment, but the diameter of the shaft 5 fitted into the iron core 4 is smaller than that of the first embodiment. Therefore, the radial length of the iron core 4 in the second embodiment (length from the outer circumference of the iron core to the inner circumference of the iron core) is longer than that of the iron core 4 in the first embodiment.

[0047] In the rotor 2A of the second embodiment, the second layer is composed of a pair of second magnet holes 12 that penetrate the iron core 4 in the axial direction, and a pair of permanent magnets 7 that are fitted into the second magnet holes 12. Flux barriers 15 are formed at the outer circumference ends of the second magnet holes 12, and flux barriers 16A are formed at the inner circumference ends of the second magnet holes 12. Both flux barriers 15 and 16A are holes (spaces) that communicate with the second magnet holes 12 and penetrate the iron core 4 in the axial direction. In the second embodiment, each flux barrier 16A is formed in the following shape as an example.

[0048] Figure 5 is a partially enlarged view of Figure 4. The overall shape of the flux barrier 16A is a roughly L-shaped configuration in which a first void portion extending in the d-axis direction and a second void portion extending in the circumferential direction are connected. The flux barrier 16A has a first inner wall portion 31, a radially extending portion 32, a second inner wall portion 33, and a protruding portion 34.

[0049] The first inner wall portion 31 of the flux barrier 16A faces the shaft 5 and extends circumferentially from the q-axis side to the d-axis side. The radially extending portion 32 of the flux barrier 16A extends radially along the d-axis. The inner circumference of the radially extending portion 32 is connected to the d-axis side of the first inner wall portion 31. The second inner wall portion 33 of the flux barrier 16A is located on the outer circumference side of the iron core 4, further than the first inner wall portion 31, and extends in an arc shape that is convex toward the inner circumference. The outer circumference of the second inner wall portion 33 is connected to the outer circumference side of the radially extending portion 32, and the inner circumference of the second inner wall portion 33 is connected to the protruding portion 34.

[0050] The protrusion 34 is formed at the q-axis end of the flux barrier 16A. The protrusion 34, in the portion of the flux barrier 16A that protrudes toward the q-axis, forms an air gap that protrudes further toward the outer circumference of the iron core 4 than the second inner wall portion 33, and plays a function in suppressing short circuits of the magnetic flux of the permanent magnet 7.

[0051] The protruding portion 34 has a first portion 34a connected to the q-axis side of the first inner wall portion 31, a second portion 34b connected to the inner circumference (q-axis side) of the second inner wall portion 33, and a connecting portion 34c connecting the first portion 34a and the second portion 34b. The first portion 34a is an example of a linear portion.

[0052] The first portion 34a forms the q-axis side end of the flux barrier 16A and is formed to extend linearly along the q-axis from the q-axis side of the first inner wall portion 31. By forming the first portion 34a linearly along the q-axis, it is possible to increase the size of the protruding portion 34 while ensuring sufficient width between the flux barriers 16A of adjacent magnetic poles separated by the q-axis. In addition, although Figures 4 and 5 show an example in which the second portion 34b is formed linearly, the second portion 34b may have other shapes such as curved shapes.

[0053] Furthermore, the protrusion 34 may be formed to protrude further outward from the core 4 than the inner circumference end 7b on the q-axis side of the permanent magnet 7. This further suppresses short-circuiting of the magnetic flux of the permanent magnet 7 by the protrusion 34. The tip of the protrusion 34 may also be formed to be located further inward than the inner circumference end 7b on the q-axis side of the permanent magnet 7.

[0054] The flux barrier 16A is connected to the second magnet hole 12 in the middle of the second inner wall portion 33. As a result, the flux barrier 16A has a portion that protrudes inward from the inner circumferential end portion 7b of the permanent magnet 7, and a portion that protrudes outward from the inner circumferential end portion 7b of the permanent magnet 7.

[0055] The portion of the flux barrier 16A that protrudes inward faces the entire first inner wall portion 31, the region in the radially extending portion 32 located further inward than the inner end 7b of the permanent magnet 7, and the region in the second inner wall portion 33 located further inward than the inner end 7b of the permanent magnet 7. The portion of the flux barrier 16A that protrudes outward faces the region in the radially extending portion 32 located further outward than the inner end 7b of the permanent magnet 7, and the region in the second inner wall portion 33 located further outward than the inner end 7b of the permanent magnet 7.

[0056] Furthermore, the flux barrier 16A has a portion that protrudes q-axis further than the q-axis end of the inner circumference end 7b of the permanent magnet 7, and a portion that protrudes d-axis further than the d-axis end of the inner circumference end 7b of the permanent magnet 7. Note that the portion of the flux barrier 16 that protrudes q-axis further than the dashed line (shown as a dotted line in Figure 5) that extends along the q-axis side surface of the permanent magnet 7, as shown in Figure 5.

[0057] The portion of the flux barrier 16A protruding toward the q-axis side faces a region on the second inner wall portion 33 that is located on the q-axis side of the inner peripheral end portion 7b of the permanent magnet 7, and a region on the first inner wall portion 31 that is located on the q-axis side of the inner peripheral end portion 7b of the permanent magnet 7, respectively. The portion of the flux barrier 16A protruding toward the d-axis side faces the entire radially extending portion 32, a region on the second inner wall portion 33 that is located on the d-axis side of the inner peripheral end portion 7b of the permanent magnet 7, and a region on the first inner wall portion 31 that is located on the d-axis side of the inner peripheral end portion 7b of the permanent magnet 7, respectively.

[0058] Also, for the flux barrier 16A, the width W1 in the first direction Dir1 from the inner peripheral end portion 7b (the q-axis side end portion) of the permanent magnet 7 to the first inner wall portion 31 is smaller than the width W2 in the second direction Dir2 from the inner peripheral end portion 7b (the d-axis side end portion) of the permanent magnet 7 to the radially extending portion 32 (W1 < W2). Here, the first direction Dir1 is a direction parallel to the d-axis of the magnetic pole center, and the second direction Dir2 is a direction orthogonal to the first direction Dir1. That is, the flux barrier 16A is formed such that the width W1 in the first direction Dir1 along the d-axis at the portion protruding toward the q-axis side is smaller than the width W2 in the second direction Dir2 at the portion protruding toward the d-axis side.

[0059] Also, in one magnetic pole, a pair of flux barriers 16A are formed on the iron core 4 in a line-symmetric pattern such that the radially extending portion 32 faces with the d-axis as the center. As a result, between the pair of flux barriers 16A, a bridge portion 24 extending radially along the d-axis is formed, similar to the rotor 2 of the first embodiment.

[0060] In the rotor 2A of the second embodiment, the flux barrier 16A formed at the inner peripheral end portion 7b of the second layer of the permanent magnet 7 has a portion protruding toward the d-axis side and a portion protruding toward the q-axis side from the inner peripheral end portion of the permanent magnet 7. Therefore, the rotor 2A of the second embodiment can also obtain the same effect as the rotor 2 of the first embodiment.

[0061] Furthermore, in the rotor 2A of the second embodiment, the flux barrier 16A is formed such that the width W1 in the first direction Dir1 at the portion protruding towards the q-axis is smaller than the width W2 in the second direction Dir2 at the portion protruding towards the d-axis. As a result, in the rotor 2A of the second embodiment, the amount of protrusion of the flux barrier 16A towards the inner circumference is smaller compared to the rotor 2 of the first embodiment, and the length of the core 4 from the first inner wall portion 31 of the flux barrier 16A to the inner surface of the core 4 can be made larger. This makes it possible to further improve the mechanical strength of the rotor 2A. Furthermore, according to the second embodiment, while improving the mechanical strength of the rotor 2A, the width W2 of the portion of the flux barrier 16A that protrudes toward the d-axis can be increased, thereby sufficiently suppressing the short circuit of the magnetic flux of the permanent magnet 7 toward the d-axis at the portion protruding toward the d-axis.

[0062] Furthermore, in the second embodiment, by forming a protrusion 34 at the q-axis side end of the flux barrier 16A, the function of suppressing short circuits of the magnetic flux of the permanent magnet 7 can be improved even in the portion of the flux barrier 16A that protrudes on the q-axis side.

[0063] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention.

[0064] For example, although the above embodiment described a case where the rotating electric machine 1 is a motor, the embedded magnet rotor of the present invention may also be applied to a generator.

[0065] In the above embodiment, an example was described in which permanent magnets 6 and 7 are arranged in two layers on one magnetic pole. However, in the embedded magnet rotor of the present invention, there may be configurations in which only one layer of permanent magnets is arranged on one magnetic pole, or configurations in which three or more layers of permanent magnets are arranged on one magnetic pole. In these cases, the configuration of the flux barrier 16 (or flux barrier 16A) in the above embodiment may be applied to the inner circumference end of the permanent magnet located on the innermost circumference.

[0066] Although the above embodiment describes an example configuration with an 8-pole rotor, the number of poles of the rotor 2 is not limited to the above embodiment. Furthermore, the shape of the permanent magnet used in the rotor 2 is not limited to the rectangular cross-section of the above embodiment; permanent magnets with an arc cross-section or the like may be used.

[0067] In the above embodiment, an example was described in which the permanent magnets and flux barriers are arranged symmetrically with respect to the d-axis at the magnetic poles of the rotor 2. However, the permanent magnets and flux barriers may also be arranged asymmetrically with respect to the d-axis at the magnetic poles of the rotor 2.

[0068] Furthermore, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0069] 1…Rotating electric machine, 2,2A…Rotor, 3…Stator, 4…Core, 5…Shaft, 6,7…Permanent magnet, 11…First magnet hole, 12…Second magnet hole, 13,14,15,16,16A…Flux barrier, 21…Inner wall section, 22,32…Radial extension section, 23…Hypotenuse section, 24…Bridge section, 31…First inner wall section, 33…Second inner wall section, 34…Protruding section

Claims

1. An embedded magnet type rotor having multiple magnetic poles formed in the circumferential direction of the iron core, Each of the aforementioned magnetic poles is, Magnets arranged on the iron core in a V-shaped pattern with increasing spacing toward the outer circumference of the rotor, The iron core comprises a pair of flux barriers formed on the inner circumference end of the magnet, The flux barrier is formed to protrude further inward than the inner circumference end of the magnet, and has a portion that protrudes toward the d-axis of the magnetic pole further than the inner circumference end of the magnet and a portion that protrudes toward the q-axis of the magnetic pole further than the inner circumference end of the magnet. The flux barrier has a portion that protrudes inward from the inner circumference end of the magnet and a portion that protrudes outward from the inner circumference end of the magnet, at a position on the d-axis side of the inner circumference end of the magnet. When the direction along the d-axis is defined as the first direction and the direction perpendicular to the d-axis is defined as the second direction, the portion of the flux barrier that protrudes toward the q-axis side of the magnetic pole is formed extending in the second direction. The flux barrier is formed such that the width in the first direction at the portion protruding towards the q-axis is smaller than the width in the second direction at the portion protruding towards the d-axis. Embedded magnetic rotor.

2. The iron core has a bridge portion extending radially along the d-axis between a pair of flux barriers. The embedded magnet type rotor according to claim 1.

3. The bridge portion is formed with a width on the outer circumference that is wider than the width on the inner circumference. The embedded magnet type rotor according to claim 2.

4. The portion of the flux barrier that protrudes toward the q-axis has a shape that includes a projection that protrudes toward the outer circumference of the iron core. The embedded magnet type rotor according to claim 1.

5. The aforementioned protrusion is formed at the q-axis end of the flux barrier, The protruding portion and the q-axis side end of the flux barrier have a linear portion along the q-axis. The embedded magnet type rotor according to claim 4.

6. The aforementioned protrusion is formed to protrude outward from the outer circumference of the iron core, beyond the inner circumference end of the magnet. The embedded magnet type rotor according to claim 4.

7. The iron core further comprises a shaft extending along its axis of rotation, The flux barrier has portions that protrude inward from the inner circumference end of the magnet, and these portions are arranged in an annular manner on the iron core along the outer circumference of the shaft. The embedded magnet type rotor according to claim 1.

8. The magnetic pole has multiple layers of magnets arranged from the outer circumference to the inner circumference. The pair of flux barriers are formed at the inner circumference ends of the magnets, which are positioned on the inner circumference side. The embedded magnet type rotor according to claim 1.

9. Stator and, The embedded magnet rotor according to any one of claims 1 to 8 A rotating electric machine equipped with the following features.

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