Rotary electric machine, rotary electric machine unit, and electric vehicle

Abstract

A rotary electric machine (1) is provided with: a rotor (20) that has, for each pole, a first permanent magnet (22A) and a second permanent magnet (22B); and a stator (30) that has a stator core (31) and a winding (32) and is arranged relative to the rotor (20) with a gap therebetween. The first permanent magnets (22A) are disposed at positions advanced in the forward rotation direction of the rotor (20) with respect to a d-axis (d0) of the rotor (20), and the second permanent magnets (22B) are disposed at delayed positions. On the basis of the difference in heat generation level between the first permanent magnets (22A) and the second permanent magnets (22B) that generate heat in accordance with the operation of the rotary electric machine (1), one group of the magnets among the first and second permanent magnets (22A, 22B) is taken as high-heat-generation magnets, and the other as low-heat-generation magnets, and the rotor (20) is cooled by heat transfer through a fluid (50) by making the heat dissipation from the high-heat-generation magnets larger than the heat dissipation from the low-heat-generation magnet.

Description

Rotating electric machine, rotating electric machine unit, and electric vehicle

[0001] The present application relates to a rotating electric machine, a rotating electric machine unit, and an electric vehicle.

[0002] Rotating electric motors for electric vehicles are required to be small and have high output, and it is effective to reduce the maximum temperature by improving the uniformity of the temperature distribution within the rotating electric motor. Furthermore, permanent magnet synchronous motors (PMSMs) with permanent magnets in the rotor are often used for rotating electric motors for electric vehicles in order to achieve high torque.

[0003] In the rotating electric machine according to the prior art described in Patent Document 1, in a coil in which a coil wire is wound around a stator core, the amount of heat generated by the coil wire is large in portions where heat can be easily dissipated through the heat dissipation path from the coil, and is small in portions where heat cannot be easily dissipated through the heat dissipation path from the coil. This reduces the temperature distribution difference within the coil and the maximum temperature of the coil.

[0004] Japanese Patent Application Laid-Open No. 2006-14471

[0005] In the prior art described in Patent Document 1, the temperature distribution inside the coil is adjusted by varying the cross-sectional area of ​​the coil wire, and it is not possible to improve the uniformity of the temperature distribution in a rotor having permanent magnets.

[0006] This application discloses a technique for solving the above-mentioned problems, and aims to improve the uniformity of temperature distribution within a rotating electric machine having a permanent magnet in the rotor, thereby reducing the maximum temperature and achieving a smaller size and higher output. It also aims to provide a rotating electric machine unit and an electric vehicle equipped with such a rotating electric machine.

[0007] The rotating electric machine disclosed herein includes a cylindrical rotor having at least one first permanent magnet and at least one second permanent magnet for each pole, and a cylindrical stator having a stator core and windings and disposed with an air gap between the rotor and the stator. The first permanent magnet is positioned ahead of the d-axis of the rotor in the forward rotation direction of the rotor, and the second permanent magnet is positioned behind the d-axis of the rotor in the forward rotation direction of the rotor. Based on the difference in heat generation level between the first permanent magnet and the second permanent magnet, which generate heat in response to operation of the rotating electric machine, one of the first and second permanent magnets is designated as a high-heat-generation magnet and the other as a low-heat-generation magnet, and the rotor is cooled by heat transfer via a fluid, with the high-heat-generation magnet having a higher heat dissipation capacity than the low-heat-generation magnet.

[0008] In addition, the rotating electric machine unit disclosed in the present application comprises the rotating electric machine and an inverter that drives and controls the rotating electric machine, the rotor comprises a first block that has the first permanent magnet for each pole and a second block that has the second permanent magnet for each pole, arranged in the axial direction, and the inverter is arranged on one axial end side of the rotating electric machine, on the side of the first and second blocks that is closer to the block that has the low-heat-generating magnet.

[0009] In addition, the rotating electric machine unit disclosed in the present application comprises the rotating electric machine and a reducer connected to the rotating electric machine, the rotor comprises a first block having the first permanent magnet for each pole and a second block having the second permanent magnet for each pole arranged in the axial direction, and the reducer is arranged on one axial end side of the rotating electric machine, on the side of the first and second blocks closer to the block having the low heat-generating magnet.

[0010] Furthermore, the electric vehicle disclosed in the present application is driven by the rotating electric machine, and the forward rotation of the rotor is the main rotation direction, which is the rotation direction when the electric vehicle moves forward.

[0011] The rotating electric machine disclosed in the present application is a rotating electric machine having a permanent magnet in the rotor, which can improve the uniformity of temperature distribution within the rotating electric machine, reduce the maximum temperature, and achieve a compact and high-output rotating electric machine unit and an electric vehicle equipped with such a rotating electric machine.

[0012] 1 is a block diagram showing a system configuration of an electric vehicle according to a first embodiment. FIG. 1 is a cross-sectional view showing a schematic configuration of a rotating electric machine according to the first embodiment. FIG. 1 is a cross-sectional view showing a configuration of a rotor according to the first embodiment. FIG. 2 is a perspective view illustrating a configuration for one rotor pole according to the first embodiment. FIG. 3 is a cross-sectional view showing a configuration of a first block for one rotor pole according to the first embodiment. FIG. 4 is a cross-sectional view showing a configuration of a second block for one rotor pole according to the first embodiment. FIG. 5 is a diagram showing, using an electrical angle, field magnet positions in a first block of a rotor according to the first embodiment. FIG. 6 is a cross-sectional view showing a configuration of a rotor and a stator according to a second embodiment. FIG. 7 is a diagram showing, using an electrical angle, field magnet positions in a second block of a rotor according to the first embodiment. FIG. 8 is a cross-sectional view showing a configuration of a rotor and a stator according to a second embodiment. FIG. 9 is a diagram showing teeth portions in an axial end region according to the second embodiment. FIG. 10 is a diagram showing teeth portions in an axial central region according to the second embodiment. FIG. 11 is a diagram showing teeth portions in an axial central region according to another example of the second embodiment. FIG. 12 is a cross-sectional view showing a configuration of a rotor according to a third embodiment. FIG. 13 is a cross-sectional view showing a configuration of a first block for one rotor pole according to the third embodiment. FIG. 14 is a cross-sectional view showing a configuration of a second block for one rotor pole according to the third embodiment. FIG. 15 is a cross-sectional view showing a configuration of a rotor according to a fourth embodiment. FIG. 16 is a block diagram showing a system configuration of an electric vehicle according to a fifth embodiment. FIG. 17 is a cross-sectional view showing a configuration of a first block for one rotor pole according to a sixth embodiment. FIG. 22 is a cross-sectional view showing the configuration of a second block for one rotor pole according to a sixth embodiment. FIG. 23 is a cross-sectional view showing the general configuration of a rotary electric machine unit according to a seventh embodiment. FIG. 24 is a partial detailed view of FIG. 20. FIG. 25 is a cross-sectional view showing the general configuration of a rotary electric machine unit according to an eighth embodiment. FIG. 26 is a partial detailed view of FIG. 22. FIG. 27 is a cross-sectional view showing the configuration of a rotor according to a ninth embodiment. FIG. 28 is a cross-sectional view showing the configuration of one rotor pole according to the ninth embodiment. FIG. 29 is a diagram showing the field magnet position in the rotor according to the ninth embodiment using electrical angles. FIG. 30 is a cross-sectional view showing the configuration of one rotor pole according to a tenth embodiment. FIG. 31 is a block diagram showing the system configuration of an electric vehicle according to another example of the tenth embodiment. FIG. 32 is a cross-sectional view showing the general configuration of a rotary electric machine according to another example of the first to tenth embodiments.

[0013] Embodiment 1. Hereinafter, embodiment 1 will be described with reference to the drawings. FIG. 1 is a block diagram showing the system configuration of an electric vehicle according to embodiment 1. As shown in FIG. 1, electric vehicle 100 includes a motor, which is a rotating electric machine 1 that drives electric vehicle 100, a rotation sensor 2 provided on rotating electric machine 1, an inverter 3 that drives and controls rotating electric machine 1, and a battery 4 that supplies power to inverter 3. The rotation sensor 2 may be a resolver, an encoder, an MR sensor (Magneto Resistive Sensor), or the like. The rotation sensor 2 acquires rotational speed information 2a, such as the angle or angular velocity of the rotating electric machine 1.

[0014] The inverter 3 is connected to the battery 4, converts DC power from the battery 4 into AC power, and supplies it to the rotating electric machine 1. A current i of each phase (U phase, V phase, W phase) of the rotating electric machine 1 is detected, and this phase current i and rotation speed information 2a from the rotation sensor 2 are fed back to the inverter 3. A torque command T* and a rotation speed command N* for the electric vehicle 100 are also input to the inverter 3. Then, based on the torque command T* and the rotation speed command N*, the phase current i, and the rotation speed information 2a, the inverter 3 converts the DC power from the battery 4 into AC power and supplies the voltage and current of the AC power to the rotating electric machine 1 to drive and control the rotating electric machine 1.

[0015] In this embodiment, the rotating electric machine 1 is a drive motor that is driven in the power running region, i.e., that mainly performs power running, for more than half of the life cycle of the electric vehicle 100. Furthermore, the rotation direction of the rotating electric machine 1 when the electric vehicle 100 moves forward is defined as forward rotation.

[0016] 2 is a cross-sectional view showing a schematic configuration of the rotating electric machine 1, showing a cross section cut along a plane passing through the axis of the rotating electric machine 1. As shown in the figure, the rotating electric machine 1 includes a cylindrical shaft 10, a cylindrical rotor 20 fixed to the shaft 10, and a cylindrical stator 30 arranged outside the rotor 20 with a gap therebetween. The rotor 20 and the stator 30 are arranged so that their centers are concentric about an axis 10A. The shaft 10 is rotatably supported by a bearing 41, which is fitted into a bracket 42, and the bracket 42 is fastened to a housing 43 by fastening elements such as screws. The stator 30 is fixed to the housing 43.

[0017] The interior of the rotating electrical machine 1 is filled with air 50, which is a fluid, and heat generated by the rotor 20 is dissipated through the air 50 inside the rotating electrical machine 1 and the shaft 10. In other words, the rotor 20 is cooled by heat transfer through the air 50 and the shaft 10.

[0018] The stator 30 is an armature including a stator core 31 formed by laminating annular electromagnetic steel plates in the axial direction, and coils 32 wound around each tooth (not shown) of the stator core 31. A plurality of teeth are provided at equal intervals in the circumferential direction. The coils 32 include coil portions disposed within slots in the stator core 31 and coil end portions protruding from the stator core 31 on both axial sides. For convenience, the coil portions disposed within the slots are not shown in FIG. 2 . In this case, the rotating electric machine 1 has a three-phase configuration (U-phase, V-phase, and W-phase), and the stator 30 includes three-phase coils as the coils 32. The ends of each phase coil are connected to the AC terminals of the inverter 3. The stator 30 may be provided with multiple sets (e.g., two sets) of three-phase coils.

[0019] Fig. 3 is a cross-sectional view showing the configuration of the rotor 20, and schematically shows a cross section cut along a plane passing through the axis 10A of the rotating electric machine 1. Fig. 4 is a perspective view illustrating the configuration of one pole of the rotor 20. As shown in Figs. 3 and 4, the rotor 20 includes a rotor core 21 and first and second permanent magnets 22A and 22B, which serve as field magnets, and is configured of multiple stages (four stages in this case) of blocks 20A and 20B in the axial direction. Of the multiple stages of blocks 20A and 20B, the first block 20A at the axial end side includes the first permanent magnet 22A, and the second block 20B at the axial center side includes the second permanent magnet 22B.

[0020] The first and second blocks 20A, 20B are skewed at each stage and stacked in the axial direction. The skew angle is set to a mechanical angle of (±360° / number of poles / reduced-order components / 2) so that order components of torque ripple that are desired to be reduced are canceled out. In this case, the rotor 20 has eight poles, and is set to ±1.875° so as to reduce the 12th-order component. The forward rotation direction (arrow 60), which is the main rotation direction of the rotor 20, is the direction in which the rotor 20 rotates when the electric vehicle 100 moves forward, and in FIG. 4, this is the counterclockwise direction as viewed from the front. The positive direction of the skew angle is the forward rotation direction of the rotor 20.

[0021] The first and second blocks 20A, 20B are axially symmetrical with respect to the skew angles, with the first block 20A having a skew angle of +1.875° and the second block 20B having a skew angle of −1.875°. Thus, the first permanent magnet 22A is positioned +1.875° ahead of the rotor 20 in the forward rotation direction, and the second permanent magnet 22B is positioned −1.875° behind the rotor 20 in the forward rotation direction.

[0022] FIG. 5 is a cross-sectional view showing the configuration of the first block 20A for one pole of the rotor 20, taken perpendicular to the axial direction. As shown in FIG. 5, the d-axis d1 of the first block 20A alone, which is a line connecting the center of the first permanent magnet 22A and the center of rotation, is positioned ahead of the d-axis d0 of the rotor 20 as a whole in the forward rotation direction of the rotor 20 (arrow 60) by an angle θ1 (+1.875°). FIG. 6 is a cross-sectional view showing the configuration of the second block 20B for one pole of the rotor 20, taken perpendicular to the axial direction. As shown in FIG. 6, the d-axis d2 of the second block 20B alone, which is a line connecting the center of the second permanent magnet 22B and the center of rotation, is positioned behind the d-axis d0 of the rotor 20 as a whole in the forward rotation direction of the rotor 20 (arrow 60) by an angle θ2 (-1.875°).

[0023] When the d-axis d1 of the first block 20A and the d-axis d2 of the second block 20B are projected onto the same plane perpendicular to the axial direction, vector D0 indicating the direction of the d-axis d0 of the entire rotor 20 is expressed by the following equation: D0 = (L1 / (L1 + L2)) D1 + (L2 / (L1 + L2)) D2 where L1 is the axial length of the first block 20A, L2 is the axial length of the second block 20B, D1 is the two-dimensional direction vector when d1 is projected onto the plane, and D2 is the two-dimensional direction vector when d2 is projected onto the plane. In this case, L1 = L2, and d0 is located exactly midway between d1 and d2.

[0024] When the rotating electric machine 1 is powered, a certain lead angle β is generally set to utilize reluctance torque or for the purpose of flux-weakening control. This lead angle is based on the q-axis q0 of the rotor 20 as a whole. During powering operation, β is in the range of 0°<β<90°. FIG. 7 is a diagram showing the field magnet positions in the first block 20A of the rotor 20 using electrical angles. As shown in FIG. 7, the magnetic flux vector Q from the stator 30 has a lead angle β0 based on the q-axis q0 of the rotor 20 as a whole and a lead angle β1 based on the q-axis q1 of the first block 20A. Furthermore, the d-axis d1 of the first block 20A is located in the forward rotation direction of the rotor 20 (arrow 60) from the d-axis d0 of the rotor 20. The lead angles β0 and β1 have the relationship β1 = β0 - θ1 × (number of poles), where β1 = β0 - 15°.

[0025] 8 is a diagram showing the position of the field magnet in the second block 20B of the rotor 20 using electrical angles. As shown in FIG. 8, the magnetic flux vector Q from the stator 30 has an advance angle β0 based on the q-axis q0 of the rotor 20 as a whole, and an advance angle β2 based on the q-axis q2 of the second block 20B. The d-axis d2 of the second block 20B is positioned behind the d-axis d0 of the rotor 20 in the forward rotation direction of the rotor 20 (arrow 60). The advance angles β0 and β2 have a relationship of β2 = β0 - θ2 × (number of poles), and in this case, β2 = β0 + 15°.

[0026] Because the advance angle β0 is based on the q-axis q0 of the rotor 20 as a whole, the advance angle β2 based on the q-axis q2 of the second block 20B is greater than the advance angle β1 based on the q-axis q1 of the first block 20A. That is, the advance angle of the second block 20B is closer to 90 degrees than that of the first block 20A, and the amount of magnetic flux weakening is greater. Generally, when magnetic flux weakening control is performed, iron loss generated in the rotor 20 is reduced, so the second block 20B generates less heat than the first block 20A. That is, the first block 20A generates more heat than the second block 20B. Similarly, the first permanent magnet 22A generates more heat than the second permanent magnet 22B, making the first permanent magnet 22A a high-heat-generating magnet and the second permanent magnet 22B a low-heat-generating magnet.

[0027] In this embodiment, the first block 20A is disposed at the axial end, and the second block 20B is disposed at the axial center. Because the first block 20A, which generates a large amount of heat, is disposed at the axial end, the contact area with the air 50 inside the rotating electrical machine 1 is large, facilitating heat dissipation from the axial end. Furthermore, because the first block 20A is close to the end of the shaft 10, heat is easily diffused to the outside air through the shaft 10. Because the heat dissipation capability of the first block 20A, which generates a large amount of heat, is greater than that of the second block 20B, the temperature distribution between the first block 20A and the second block 20B is uniform. This reduces the maximum temperature of the entire rotor 20, enabling the rotating electrical machine 1 to be made smaller and with higher output.

[0028] Heat generated by the rotor 20 is mainly generated by the first and second permanent magnets 22A and 22B, which are field magnets. In this case, making the heat dissipation ability of the first block 20A greater than that of the second block 20B is the same as making the heat dissipation ability of the first permanent magnet 22A greater than that of the second permanent magnet 22B.

[0029] As described above, in this embodiment, the first permanent magnet 22A is a high-heat-generating magnet and the second permanent magnet 22B is a low-heat-generating magnet based on the difference in heat generation level between the first permanent magnet 22A and the second permanent magnet 22B, which generate heat in response to the operation of the rotating electric machine 1. The rotor 20 is cooled by heat transfer via a fluid, with the heat dissipation ability of the high-heat-generating magnet being greater than that of the low-heat-generating magnet. This improves the uniformity of the temperature distribution within the rotating electric machine 1, reducing the maximum temperature and enabling the rotating electric machine 1 to be made smaller and with higher output.

[0030] In this embodiment, the rotor 20 includes multiple tiers of blocks arranged in the axial direction, each tier consisting of at least one first block 20A having a first permanent magnet 22A for each pole and at least one second block 20B having a second permanent magnet 22B for each pole, with the blocks including the high-heat-generating magnets being arranged at the axial ends and the blocks including the low-heat-generating magnets being arranged at the axial center. This allows the heat dissipation of the high-heat-generating magnets to be easily and reliably greater than that of the low-heat-generating magnets, and the rotor 20 is cooled effectively.

[0031] In the above embodiment, the rotor 20 is configured with four axially arranged blocks, but the number of stages may be other than four as long as the first block 20A is arranged at the axial end side and the second block 20B is arranged at the axial center side. Also, in the above embodiment, the rotor 20 is cooled via the air 50 and the shaft 10, but the fluid is not limited to the air 50 and, for example, oil may be used.

[0032] When the rotating electric machine 1 performs regenerative operation, the second block 20B, in which the second permanent magnet 22B is arranged in a position lagging in the forward rotation direction of the rotor 20, generates a higher amount of heat than the first block 20A. The above-mentioned advance angle β is in the range of 0° < β < 90° during power running, but in the range of 90° < β < 180° during regenerative operation. That is, during regeneration, the first block, which is arranged in a phase-advancing position, has β closer to 90 degrees, which increases the amount of magnetic flux weakening and reduces the amount of heat generated. Therefore, the second block 20B generates a higher amount of heat.

[0033] In the above embodiment, the rotating electric machine 1 has been described as a drive motor that mainly performs power running, but the electric vehicle 100 may be provided with a rotating electric machine that functions as a generator separate from the drive motor. When the rotating electric machine 1 is a generator that mainly performs regenerative operation, it is configured as follows.

[0034] When the rotating electric machine 1 is a generator that mainly performs regenerative operation, the second block 20B, in which the second permanent magnets 22B are arranged in a position that is delayed in the forward rotation direction of the rotor 20, generates a higher amount of heat than the first block 20A, in which the first permanent magnets 22A are arranged in a position that is advanced in the forward rotation direction of the rotor 20. Similarly, the second permanent magnets 22B generate a higher amount of heat than the first permanent magnets 22A, making the second permanent magnets 22B high-heat-generating magnets and the first permanent magnets 22A low-heat-generating magnets. The second block 20B is arranged at the axial end of the rotor 20, and the first block 20A is arranged at the axial center. Note that the arrangement of the first block 20A and the second block 20B is reversed in Figures 3 and 4, and is not shown for convenience.

[0035] In this case, the rotor 20 is cooled by heat transfer via the fluid, with the heat dissipation of the high-heat-generating magnets (second permanent magnets 22B) being greater than that of the low-heat-generating magnets (first permanent magnets 22A). This increases the uniformity of the temperature distribution within the rotating electrical machine 1, reducing the maximum temperature and enabling the rotating electrical machine 1 to be made smaller and with higher output.

[0036] Second Embodiment Next, a second embodiment will be described with reference to the drawings. The second embodiment differs from the rotating electric machine 1 shown in the first embodiment in the configuration of the stator 30. FIG. 9 is a cross-sectional view showing the configuration of the rotor and stator according to the second embodiment, and schematically shows a cross section cut along a plane passing through the axis 10A of the rotating electric machine 1. As shown in FIG. 9, the configuration of the rotor 20 is the same as that of the first embodiment, and the stator core 31 of the stator 30, which is disposed outside the rotor 20 with a gap therebetween, has teeth with different shapes between axial end regions 31A of the stator core 31 and an axial central region 31B sandwiched between the axial end regions 31A on both sides.

[0037] The stator core 31 has teeth protruding toward the rotor 20, in this case, protruding from the outer periphery to the inner periphery, stacked in the axial direction, with multiple teeth made up of stacked teeth evenly spaced circumferentially. FIG. 10 is a diagram showing the teeth in the axial end region 31A. FIG. 11 is a diagram showing the teeth in the axial center region 31B. As shown in FIG. 10, the teeth 31AA in the axial end region 31A have a tip angle of x [°] and a base width of a [mm]. Also, as shown in FIG. 11, the teeth 31BA in the axial center region 31B have a tip angle of y (>x) [°] and a base width of b (>a) [mm]. Note that the larger the tip angle, the larger the tip width.

[0038] In this embodiment, the tooth portions 31AA in the axial end regions 31A have narrower tip and base widths than the tooth portions 31BA in the axial center region 31B. Therefore, the tooth portions 31AA in the axial end regions 31A have narrower magnetic path widths and are more susceptible to magnetic saturation than the tooth portions 31BA in the axial center region 31B. This results in less loss in the axial end regions 31A of the stator 30 than in the axial center region 31B. Furthermore, less magnetic flux passes from the tooth portions 31AA in the axial end regions 31A to the rotor 20, reducing the loss generated in the corresponding regions of the rotor 20.

[0039] As described above, in the rotor 20, the first block 20A, which generates a high amount of heat, is disposed at the axial end portion, and the second block 20B, which generates a low amount of heat, is disposed at the axial center portion. By combining this rotor 20 with the stator 30 in which the teeth 31AA in the axial end region 31A are narrower than the teeth 31BA in the axial center region 31B, the uniformity of the temperature distribution within the rotating electric machine 1 can be improved, further reducing the maximum temperature. In addition, because the teeth 31AA in the axial end region 31A are narrower than the teeth 31BA in the axial center region 31B, winding the coil 32 becomes easier.

[0040] In the stator core 31 according to the above embodiment, the tooth portions 31AA in the axial end regions 31A have narrower tip widths and root widths than the tooth portions 31BA in the axial central region 31B, but the same effect can be obtained if at least one of the tip width and root width is narrow.

[0041] FIG. 12 is a diagram showing teeth in the axial center region 31B according to another example of the second embodiment. In this case, the teeth 31AA shown in FIG. 10 are used in the axial end region 31A. As shown in FIG. 12, the teeth 31BB in the axial center region 31B have a tip angle of z (>x) [°] and a base width of b (>a) [mm]. In this example, the teeth 31BB have a flanged shape, with the tip end being wider than the base. In this example, the tip width of the teeth 31BB is larger than the base width, so the base width of the teeth 31BB may be the same as the base width of the teeth 31AA in the axial end region 31A.

[0042] In this way, the structure of the stator core 31, which combines multiple tooth portions 31AA, 31BB with different tip widths, is effective in reducing torque ripple and is particularly suitable for rotating electrical machines 1 that are operated in a manner that is sensitive to torque ripple.

[0043] Third Embodiment Next, a third embodiment will be described with reference to the drawings. In the first embodiment, the rotor 20 is configured with four blocks arranged in the axial direction, but in this third embodiment, a fluid flows in the axial direction, and the rotor is configured with two blocks arranged upstream and downstream of the fluid. Figure 13 is a cross-sectional view showing the configuration of the rotor according to the third embodiment, and schematically shows a cross section taken along a plane passing through the axis 10A of the rotating electrical machine 1.

[0044] 13, the rotor 200 includes a rotor core 21 and first and second permanent magnets 22A and 22B, and is cooled by a fluid 51, which is oil, flowing through a through-hole 55 that penetrates the rotor 200 in the axial direction. The rotor 200 is composed of a first block 200A on the upstream side of the fluid 51 in the axial direction and a second block 200B on the downstream side, with the first block 200A including the first permanent magnets 22A and the second block 200B including the second permanent magnets 22B.

[0045] FIG. 14 is a cross-sectional view showing the configuration of a first block 200A corresponding to one pole of the rotor 200, taken perpendicular to the axial direction. FIG. 15 is a cross-sectional view showing the configuration of a second block 200B corresponding to one pole of the rotor 200, taken perpendicular to the axial direction. Similar to the first embodiment, the first block 200A includes a first permanent magnet 22A arranged at a position leading in the forward rotation direction (arrow 60) of the rotor 200 for each pole. Similarly to the first embodiment, the second block 200B includes a second permanent magnet 22B arranged at a position lagging in the forward rotation direction (arrow 60) of the rotor 200 for each pole. Furthermore, a through-hole 55 penetrating the rotor 200 in the axial direction is provided for each pole of the rotor 200 on the d-axis d0 of the entire rotor 200.

[0046] As described in the first embodiment above, when the rotating electric machine 1 is in power running, a certain advance angle is set based on the q-axis q0 of the rotor 200 as a whole, for the purpose of utilizing reluctance torque or flux-weakening control. Similarly, in this embodiment, the advance angle based on the q-axis of the second block 200B is greater than the advance angle based on the q-axis of the first block 200A. That is, the advance angle of the second block 200B is closer to 90 degrees than the first block 200A, and the amount of flux weakening is greater, resulting in a lower heat generation. In this case, the first permanent magnet 22A is a high-heat-generating magnet, and the second permanent magnet 22B is a low-heat-generating magnet.

[0047] In this embodiment, the rotating electric machine 1 is a drive motor that mainly performs power running. The first block 200A, which generates a large amount of heat, is located upstream of the fluid 51 in the axial direction, and the second block 200B, which generates a small amount of heat, is located downstream. The fluid 51 flowing through the through holes 55 absorbs heat from the first block 200A and then absorbs heat from the second block 200B. The temperature of the fluid 51 in contact with the first block 200A is lower than the temperature of the fluid 51 in contact with the second block 200B, providing a high heat dissipation effect. This allows the temperatures of the first block 200A and the second block 200B to be uniform.

[0048] In this way, the heat dissipation ability of the first block 200A, which generates a large amount of heat, is made greater than that of the second block 200B, which makes the temperature distribution between the first block 200A and the second block 200B uniform. This reduces the maximum temperature of the entire rotor 200, thereby achieving a smaller, higher-output rotating electric machine 1. Note that in this case as well, making the heat dissipation ability of the first block 200A greater than that of the second block 200B is the same as making the heat dissipation ability of the first permanent magnet 22A greater than that of the second permanent magnet 22B.

[0049] In the third embodiment, the rotating electric machine 1 has been described as a drive motor that primarily performs power running, but when the rotating electric machine 1 is a generator that primarily performs regenerative operation, it is configured as follows. In this case, as described above, the second permanent magnet 22B has a higher heat generation amount than the first permanent magnet 22A, so that the second permanent magnet 22B is a high-heat-generation magnet and the first permanent magnet 22A is a low-heat-generation magnet. The second block 200B, which generates a high heat generation amount, is disposed upstream of the fluid 51 in the axial direction, and the first block 200A, which generates a low heat generation amount, is disposed downstream.

[0050] In this case as well, the rotor 20 is cooled by heat transfer via the fluid 51, with the heat dissipation capacity of the high-heat-generating magnets (second permanent magnets 22B) being greater than that of the low-heat-generating magnets (first permanent magnets 22A). This increases the uniformity of the temperature distribution within the rotating electric machine 1, reducing the maximum temperature and enabling the rotating electric machine 1 to be made smaller and with higher output.

[0051] Fourth Embodiment Next, a fourth embodiment will be described with reference to the drawings. In the third embodiment, the rotor 200 is cooled by the fluid 51 flowing through the through holes 55 provided for each pole of the rotor 200. In this fourth embodiment, no through holes are provided, and the rotor is cooled by the fluid flowing in the axial direction within the rotating electric machine 1. Figure 16 is a cross-sectional view showing the configuration of the rotor according to the fourth embodiment, and schematically shows a cross section taken along a plane passing through the axis 10A of the rotating electric machine 1. In this case, the rotating electric machine 1 will be described as a drive motor that mainly performs power running.

[0052] As shown in Figure 16, the rotor 201 includes a rotor core 21 and first and second permanent magnets 22A and 22B, and is cooled by a fluid 50A, which is air flowing in the axial direction. The rotor 201 is composed of a first block 20A located upstream of the fluid 50A in the axial direction and a second block 20B located downstream. The first block 20A includes the first permanent magnets 22A, and the second block 20B includes the second permanent magnets 22B. The configuration of the first and second blocks 20A and 20B is the same as that of the first embodiment (see Figures 5 and 6). In this case, the first permanent magnets 22A are high-heat-generating magnets, and the second permanent magnets 22B are low-heat-generating magnets.

[0053] In this embodiment, as in the third embodiment, the first block 20A, which generates a high amount of heat, is arranged upstream of the fluid 50A in the axial direction, and the second block 20B, which generates a low amount of heat, is arranged downstream. The fluid 50A flowing in the axial direction first absorbs heat from the first block 20A and then absorbs heat from the second block 20B. The temperature of the fluid 50A in contact with the first block 20A is lower than the temperature of the fluid 50A in contact with the second block 20B, resulting in a high heat removal effect. This allows the temperatures of the first block 20A and the second block 20B to be uniform.

[0054] In this way, the heat dissipation of the first block 20A, which generates a large amount of heat, is made greater than that of the second block 20B, which results in a uniform temperature distribution between the first block 20A and the second block 20B. This reduces the maximum temperature of the entire rotor 201, thereby enabling a smaller, more powerful rotating electric machine 1. Furthermore, since the rotating electric machine 1 is a ventilation-cooled type that does not require the provision of additional through holes, it can be realized with a simple configuration.

[0055] In the fourth embodiment, the rotating electric machine 1 has been described as a drive motor that primarily performs power running, but when the rotating electric machine 1 is a generator that primarily performs regenerative operation, it is configured as follows. In this case, as described above, the second permanent magnet 22B has a higher heat generation amount than the first permanent magnet 22A, so that the second permanent magnet 22B is a high-heat-generation magnet and the first permanent magnet 22A is a low-heat-generation magnet. The second block 20B, which generates a high heat generation amount, is disposed upstream of the fluid 50A in the axial direction, and the first block 20A, which generates a low heat generation amount, is disposed downstream.

[0056] In this case as well, the rotor 201 is cooled by heat transfer via the fluid 50 A, with the heat dissipation capacity of the high-heat-generating magnet (second permanent magnet 22B) being greater than that of the low-heat-generating magnet (first permanent magnet 22A). This increases the uniformity of the temperature distribution within the rotating electric machine 1, reducing the maximum temperature and enabling the rotating electric machine 1 to be made smaller and with higher output.

[0057] The fluids 51 and 50A used in the third and fourth embodiments are not limited to oil or air, but may be any fluid with high heat transfer performance.

[0058] Fifth Embodiment Next, a fifth embodiment will be described with reference to the drawings. Fig. 17 is a block diagram showing the system configuration of an electric vehicle according to the fifth embodiment. As shown in Fig. 17, an electric vehicle 100A includes a motor, which is a rotating electric machine 1 that drives the electric vehicle 100A, a rotation sensor 2 provided in the rotating electric machine 1, an inverter 3 that drives and controls the rotating electric machine 1, a battery 4 that supplies power to the inverter 3, and a flow path switch 5 provided in the rotating electric machine 1. The rotating electric machine 1, the rotation sensor 2, the inverter 3, and the battery 4 are the same as those described with reference to Fig. 1 in the first embodiment above, but the configuration of the rotor within the rotating electric machine 1 is the same as that in the third or fourth embodiment above.

[0059] In this case, an example will be shown in which the rotating electric machine 1 according to the third embodiment is used. As shown in the third embodiment, the rotor 200 is cooled by the fluid 51 flowing axially through the through hole 55. The flow path switch 5 reverses the direction of the fluid 51 when the rotating electric machine 1 switches between powering operation and regenerative operation. The flow path switch 5 has, for example, a solenoid-type directional control valve therein and is operated by a switching command 3 a from the inverter 3. When the driving condition of the rotating electric machine 1 changes from powering to regenerative operation, the inverter 3 provides the switching command 3 a to the flow path switch 5, which reverses the flow direction of the fluid 51. As a result, the fluid 51 flowing from the first block 200A to the second block 200B during powering is reversed during regeneration, and flows from the second block 200B to the first block 200A.

[0060] As described above, the first block 200A includes the first permanent magnets 22A arranged at positions advanced in the forward rotation direction of the rotor 200 for each pole, and the second block 200B includes the second permanent magnets 22B arranged at positions delayed in the forward rotation direction of the rotor 200 for each pole. Between the first block 200A and the second block 200B, the first block 200A generates more heat during power running, and the second block 200B generates more heat during regeneration.

[0061] In this embodiment, the rotary electric machine 1 is provided with a flow path switch 5 that reverses the flow direction of the fluid 51, so that the fluid 51 flows from the first block 200A or the second block 200B, whichever generates more heat, to the block with the lesser heat generation, not only during power running but also during regeneration. This allows the rotor 200 to be cooled effectively, and the temperature distribution between the first block 200A and the second block 200B is made uniform even during regeneration, thereby reducing the maximum temperature of the entire rotor 200.

[0062] While the above embodiment has shown an example in which the rotating electric machine 1 according to the above embodiment 3 is used, the rotating electric machine 1 according to the above embodiment 4 can also be used in the same way. In this case, too, when the drive condition of the rotating electric machine 1 changes from powering to regeneration, the inverter 3 issues a switching command 3a to the flow path switch 5, and the flow path switch 5 reverses the flow direction of the fluid 50A. As a result, the fluid 50A that flows from the first block 20A toward the second block 20B during powering is reversed during regeneration, and flows from the second block 20B toward the first block 20A. Therefore, the rotor 201 can be effectively cooled not only during powering but also during regeneration.

[0063] Furthermore, the flow path switch 5 is not limited to being operated by a command from the inverter 3, and may perform switching based on other information, for example, the current value or angular velocity information of the rotating electrical machine 1.

[0064] The fifth embodiment can also be applied to a rotating electric machine 1 that is a generator that primarily performs regenerative operation. In this case, the second permanent magnet 22B is a high-heat-generating magnet, and the first permanent magnet 22A is a low-heat-generating magnet. The second block 20B, which generates a high amount of heat, is located upstream of the fluid 50A in the axial direction, and the first block 20A, which generates a low amount of heat, is located downstream. When the driving condition of the rotating electric machine 1 changes from regeneration to power running, the flow path switch 5 reverses the flow direction of the fluid 50A. As a result, the fluid 50A, which flows from the second block 20B to the first block 20A during regeneration, is reversed during power running, and flows from the first block 20A to the second block 20B. This allows the rotor 201 to be effectively cooled not only during regeneration but also during power running.

[0065] Sixth Embodiment Next, a sixth embodiment will be described with reference to the drawings. The rotating electric machine 1 will be described as a drive motor that mainly performs power running. In the third embodiment, the through-hole 55 penetrating in the axial direction was provided on the d-axis d0 of the rotor 200, but in this sixth embodiment, the through-hole is provided in a different position. FIG. 18 is a cross-sectional view showing the configuration of a first block 210A corresponding to one pole of the rotor 200, and shows a cross-section perpendicular to the axial direction. FIG. 19 is a cross-sectional view showing the configuration of a second block 210B corresponding to one pole of the rotor 200, and shows a cross-section perpendicular to the axial direction.

[0066] In this sixth embodiment, as in the third embodiment, the rotor 200 includes a rotor core 21 and first and second permanent magnets 22A, 22B, and is cooled by oil fluid 51 that flows through a through-hole 55A that penetrates the rotor 200 in the axial direction. The rotor 200 is composed of a first block 210A on the upstream side of the fluid 51 in the axial direction and a second block 210B on the downstream side, with the first block 210A including the first permanent magnets 22A and the second block 210B including the second permanent magnets 22B.

[0067] The first block 210A includes a first permanent magnet 22A arranged at a position advanced in the forward rotation direction (arrow 60) of the rotor 200 for each pole. The second block 210B includes a second permanent magnet 22B arranged at a position delayed in the forward rotation direction (arrow 60) of the rotor 200 for each pole. Each pole of the rotor 200 is also provided with a through-hole 55A penetrating in the axial direction. The through-hole 55A is arranged on the d-axis d1 side of the first block 210A with respect to the d-axis d0 of the rotor 200. That is, the through-hole 55A is arranged at a position where the distance DA from the through-hole 55A to the first permanent magnet 22A is shorter than the distance DB from the through-hole 55A to the second permanent magnet 22B.

[0068] In addition, in order to make the first permanent magnet 22A and the second permanent magnet 22B have the same magnet temperature, it is preferable that the ratio between the distance DA and the distance DB is the inverse ratio of the heat generation amounts of the first and second permanent magnets 22A and 22B.

[0069] In this embodiment, the through-holes 55A extending axially are positioned closer to the first permanent magnets 22A, which are high-heat-generating magnets, than to the second permanent magnets 22B, which are low-heat-generating magnets. This allows the heat generated by the first permanent magnets 22A in the first block 210A to escape into the fluid 51 flowing through the through-holes 55A more easily than the heat generated by the second permanent magnets 22B in the second block 210B. This results in greater heat dissipation from the first permanent magnets 22A (high-heat-generating magnets) than from the second permanent magnets 22B (low-heat-generating magnets). This allows the first block 210A, which generates more heat, to dissipate more heat than the second block 210B, which generates less heat, resulting in a more uniform temperature distribution between the first block 210A and the second block 210B. This reduces the maximum temperature of the entire rotor 200, enabling the rotating electric machine 1 to be smaller and more powerful.

[0070] In this embodiment, the first block 210A is positioned upstream of the fluid 51, and the second block 210B is positioned downstream. This, combined with the effect of the placement of the through holes 55A, further improves the heat dissipation properties of the first block 210A, which generates a large amount of heat, thereby reducing the maximum temperature of the entire rotor 200.

[0071] The arrangement of the first blocks 210A and the second blocks 210B is not limited to the above embodiment, and may be the same as that of the first embodiment, or the first blocks 210A and the second blocks 210B may be arranged alternately in four stages in total. Even in these cases, by providing the through holes 55A at positions closer to the first permanent magnets 22A than the second permanent magnets 22B, the heat dissipation ability of the first permanent magnets 22A becomes greater than that of the second permanent magnets 22B, and the maximum temperature of the entire rotor 200 can be reduced.

[0072] In this embodiment, the fluid 51 is not limited to oil or air, but may be any fluid with high heat transfer performance.

[0073] The sixth embodiment can also be applied to a rotating electric machine 1 that is a generator that primarily performs regenerative operation. In this case, the second permanent magnet 22B is a high-heat-generating magnet, and the first permanent magnet 22A is a low-heat-generating magnet. The second block 210B, which generates a high amount of heat, is disposed upstream of the fluid 51 in the axial direction, and the first block 210A, which generates a low amount of heat, is disposed downstream. Each pole of the rotor 200 is provided with a through-hole 55A that penetrates the rotor 200 in the axial direction. In this case, the through-hole 55A is disposed on the d-axis d2 side of the second block 210B with respect to the d-axis d0 of the rotor 200. That is, the through-hole 55A is disposed at a position where the distance from the through-hole 55A to the second permanent magnet 22B is shorter than the distance from the through-hole 55A to the first permanent magnet 22A.

[0074] Therefore, the heat dissipation of the second permanent magnet 22B (high heat generating magnet) is greater than that of the first permanent magnet 22A (low heat generating magnet), and the maximum temperature of the entire rotor 200 can be reduced.

[0075] Seventh Embodiment Next, a seventh embodiment will be described with reference to the drawings. The rotating electric machine 1 will be described as a drive motor that mainly performs power running. FIG. 20 is a cross-sectional view showing the schematic configuration of a rotating electric machine unit according to the seventh embodiment, showing a cross section cut along a plane passing through the axis of the rotating electric machine 1. FIG. 21 is a partial detailed view of FIG. 20, showing a schematic cross section. As shown in the figure, the rotating electric machine unit 6 has a structure in which the rotating electric machine 1 and an inverter 3 that drives the rotating electric machine 1 are integrated, and the inverter 3 is disposed on one axial end side of the rotating electric machine 1.

[0076] In this embodiment, the rotating electric machine 1 uses a rotor 201 in which a first block 20A and a second block 20B are arranged in two stages in the axial direction. The configuration of the rotating electric machine 1 other than the rotor 201 is the same as that of the first embodiment shown in Fig. 2. The configurations of the first and second blocks 20A and 20B are also the same as those of the first embodiment (see Figs. 5 and 6), with the first block 20A including a first permanent magnet 22A and the second block 20B including a second permanent magnet 22B.

[0077] As shown in the figure, the inverter 3 is disposed on the shaft end side closer to the second block 20B, which generates a lower amount of heat. That is, the first block 20A, which generates a higher amount of heat, is disposed at a position away from the inverter 3, and the second block 20B, which generates a lower amount of heat, is disposed at a position closer to the inverter 3. When the rotating electric machine 1 is driven, not only heat is generated on the rotating electric machine 1 side, but also heat is generated by the inverter 3. In the rotating electric machine unit 6 according to this embodiment, the first block 20A, which generates a higher amount of heat, is disposed at a position away from the inverter 3, thereby reducing the thermal effect from the inverter 3 on the first block 20A.

[0078] As a result, the heat dissipation properties of the first permanent magnet 22A (high heat generating magnet) are greater than those of the second permanent magnet 22B (low heat generating magnet), the temperature distribution between the first block 20A and the second block 20B is made uniform, and the maximum temperature of the entire rotor 201 can be reduced.

[0079] In the above embodiment, as in the fourth embodiment, the first block 20A may be arranged on the upstream side and the second block 20B on the downstream side, and the cooling fluid 50A may be made to flow in the axial direction, thereby further achieving uniform temperature distribution.

[0080] Furthermore, similar to the third or sixth embodiment, the cooling fluid 50A may be caused to flow in the axial direction using the rotor 200 having the through holes 55, 55A. In this case, too, by locating the first blocks 200A, 210A, which generate a large amount of heat, at a position away from the inverter 3, the thermal effect from the inverter 3 on the first blocks 200A, 210A can be reduced, and the temperature distribution can be further uniformed.

[0081] Eighth Embodiment Next, an eighth embodiment will be described with reference to the drawings. The rotating electric machine 1 will be described as a drive motor that mainly performs power running. FIG. 22 is a cross-sectional view showing a schematic configuration of a rotating electric machine unit according to the eighth embodiment, showing a cross section cut along a plane passing through the axis of the rotating electric machine 1. FIG. 23 is a partial detailed view of FIG. 22, showing a schematic cross section. As shown in the figure, the rotating electric machine unit 8 has a structure including the rotating electric machine 1 and a reducer 7 connected to a shaft 10 of the rotating electric machine 1 to adjust the rotational speed, and the reducer 7 is disposed on one axial end side of the rotating electric machine 1.

[0082] In this embodiment, the rotating electric machine 1 uses a rotor 201 in which a first block 20A and a second block 20B are arranged in two stages in the axial direction. The configuration of the rotating electric machine 1 other than the rotor 201 is the same as that of the first embodiment shown in Fig. 2. The configurations of the first and second blocks 20A and 20B are also the same as those of the first embodiment (see Figs. 5 and 6), with the first block 20A including a first permanent magnet 22A and the second block 20B including a second permanent magnet 22B.

[0083] As shown in the figure, the reducer 7 is disposed on the shaft end side closer to the second block 20B, which generates a lower amount of heat. That is, the first block 20A, which generates a higher amount of heat, is disposed at a position away from the reducer 7, and the second block 20B, which generates a lower amount of heat, is disposed at a position closer to the reducer 7. When the rotating electric machine 1 is driven, not only heat is generated on the rotating electric machine 1 side, but also by the reducer 7. In the rotating electric machine unit 8 according to this embodiment, the first block 20A, which generates a higher amount of heat, is disposed at a position away from the reducer 7, thereby reducing the thermal effect of the reducer 7 on the first block 20A.

[0084] As a result, the heat dissipation properties of the first permanent magnet 22A (high heat generating magnet) are greater than those of the second permanent magnet 22B (low heat generating magnet), the temperature distribution between the first block 20A and the second block 20B is made uniform, and the maximum temperature of the entire rotor 201 can be reduced.

[0085] In the above embodiment, as in the fourth embodiment, the first block 20A may be arranged on the upstream side and the second block 20B on the downstream side, and the cooling fluid 50A may be made to flow in the axial direction, thereby further achieving uniform temperature distribution.

[0086] Furthermore, similar to the third or sixth embodiment, the cooling fluid 50A may be caused to flow in the axial direction by using the rotor 200 having the through holes 55, 55A. In this case, too, by arranging the first blocks 200A, 210A, which generate a large amount of heat, at a position away from the reducer 7, the thermal influence from the inverter 3 on the first blocks 200A, 210A can be reduced, and the temperature distribution can be further uniformed.

[0087] Although the seventh and eighth embodiments have been described with reference to the rotating electric machine 1 as a drive motor primarily performing power running, they can also be applied to a rotating electric machine 1 that is a generator primarily performing regenerative operation. In this case, the second permanent magnet 22B is a high-heat-generating magnet, and the first permanent magnet 22A is a low-heat-generating magnet. The second block 20B, which generates a high amount of heat, is located upstream of the fluid 50A in the axial direction, and the first block 20A, which generates a low amount of heat, is located downstream. The inverter 3 (or the reducer 7), which generates heat, is disposed on the axial end closer to the first block 20A, which generates a low amount of heat. That is, the second block 20B, which generates a high amount of heat, is located away from the inverter 3 (or the reducer 7), and the first block 20A, which generates a low amount of heat, is located closer to the inverter 3 (or the reducer 7). As in the seventh and eighth embodiments, this uniformizes the temperature distribution between the first block 20A and the second block 20B, thereby reducing the maximum temperature of the entire rotor 201.

[0088] Ninth Embodiment Next, a ninth embodiment will be described with reference to the drawings. The rotating electric machine 1 will be described as a drive motor that mainly performs power running. In the above-described embodiments, rotors 20, 200, 201 having multiple stages of blocks in the axial direction are used, but in this embodiment, a single structure is used in the axial direction. Figure 24 is a cross-sectional view showing the configuration of a rotor according to the ninth embodiment, and schematically shows a cross section cut along a plane passing through the axis 10A of the rotating electric machine 1. Figure 25 is a cross-sectional view showing the configuration for one pole of the rotor, showing a cross section perpendicular to the axial direction.

[0089] 24 and 25 , the rotor 220 includes a rotor core 21 and first and second permanent magnets 22A and 22B, and is cooled by oil-based fluid 51 that flows through through-holes 55A that penetrate the rotor 220 in the axial direction. The rotor 220 includes, for each pole, a first permanent magnet 22A that is positioned ahead of the rotor 220 in the forward rotation direction (arrow 60), a second permanent magnet 22B that is positioned behind the rotor 220, and through-holes 55A through which the fluid 51 flows.

[0090] The first permanent magnet 22A and the second permanent magnet 22B are arranged symmetrically or approximately symmetrically with respect to the d-axis d0 of the rotor 220. The through-hole 55A is arranged on the first permanent magnet 22A side with respect to the d-axis d0 of the rotor 220. That is, the through-hole 55A is provided at a position where the distance DA from the through-hole 55A to the first permanent magnet 22A is shorter than the distance DB from the through-hole 55A to the second permanent magnet 22B.

[0091] FIG. 26 is a diagram showing the position of the field magnets in the rotor 220 using electrical angles. As described above, when the rotating electric machine 1 is powered, it is operated with a constant lead angle β (0°<β<90°) based on the q-axis q0 in order to utilize reluctance torque or perform flux-weakening control. As shown in FIG. 26 , the magnetic flux vector Q from the stator 30 has a lead angle β0 based on the q-axis q0 of the rotor 220. Furthermore, with respect to the d-axis d0 of the rotor 220, the first permanent magnet 22A is positioned ahead in the forward rotation direction (arrow 60), and the second permanent magnet 22B is positioned behind in the forward rotation direction (arrow 60).

[0092] When the rotor 220 is driven with the advance angle β0, the second permanent magnet 22B is more strongly affected by weakening the field magnetic flux than the first permanent magnet 22A. Therefore, the second permanent magnet 22B and the rotor core 21 around it generate less heat than the first permanent magnet 22A and the rotor core 21 around it. In other words, the first permanent magnet 22A generates more heat than the second permanent magnet 22B, making the first permanent magnet 22A a high-heat-generating magnet and the second permanent magnet 22B a low-heat-generating magnet.

[0093] On the other hand, the heat transfer from the first and second permanent magnets 22A, 22B to the fluid 51 increases as the distance to the fluid 51 decreases. That is, the first permanent magnet 22A, which is closer to the through hole 55A through which the fluid 51 flows, is more likely to extract heat than the second permanent magnet 22B, and has higher heat dissipation properties.

[0094] In this embodiment, each pole of the rotor 220 is provided with a first permanent magnet 22A and a second permanent magnet 22B. Furthermore, a through-hole 55A through which a fluid 51 flows in the axial direction is provided for each pole, closer to the first permanent magnet 22A (high-heat-generating magnet) than to the second permanent magnet 22B (low-heat-generating magnet). Therefore, heat generated by the first permanent magnet 22A is more likely to escape into the fluid 51 flowing through the through-hole 55A than heat generated by the second permanent magnet 22B, resulting in greater heat dissipation from the first permanent magnet 22A than from the second permanent magnet 22B. In this way, the first permanent magnet 22A, which generates a higher amount of heat, can dissipate heat more efficiently than the second permanent magnet 22B, which generates a lower amount of heat. This allows for a more uniform temperature distribution in the rotor 220, reducing the maximum temperature and enabling the rotating electric machine 1 to be made smaller and with higher output.

[0095] It is desirable to provide through holes 55A in positions that do not interfere with the magnetic circuit, and it is desirable to select distances DA and DB between first and second permanent magnets 22A, 22B and through holes 55A so that there is no interference with the magnetic circuit due to through holes 55A. For example, through holes 55A are provided in positions that make distance DA as small as possible within an area where the magnetic flux density of rotor core 21 would be 0.1 T or less if through holes 55A were not provided.

[0096] In addition, in order to make the first permanent magnet 22A and the second permanent magnet 22B have the same magnet temperature, the ratio of the distance DA to the distance DB may be set to the inverse ratio of the heat generation amounts of the first and second permanent magnets 22A and 22B.

[0097] Although the above-described ninth embodiment has been described as a rotating electric machine 1 serving as a drive motor primarily performing power running, the present invention can also be applied to a rotating electric machine 1 serving as a generator primarily performing regenerative operation. In this case, the second permanent magnet 22B is a high-heat-generating magnet, and the first permanent magnet 22A is a low-heat-generating magnet, and the through-hole 55A is disposed on the second permanent magnet 22B side with respect to the d-axis d0 of the rotor 220. That is, the through-hole 55A is disposed in a position where the distance from the through-hole 55A to the second permanent magnet 22B is shorter than the distance from the through-hole 55A to the first permanent magnet 22A. This allows the second permanent magnet 22B, which generates a higher amount of heat, to dissipate heat more effectively than the first permanent magnet 22A, which generates a lower amount of heat. This allows the temperature distribution in the rotor 220 to be uniform, reducing the maximum temperature, and achieving a smaller, higher-output rotating electric machine 1.

[0098] Tenth Embodiment Next, a tenth embodiment will be described with reference to the drawings. The rotating electric machine 1 will be described as a drive motor that mainly performs power running. In the ninth embodiment, the rotor 220 had one through-hole 55A that penetrates in the axial direction for each pole, but in this embodiment, two through-holes are provided. Figure 27 is a cross-sectional view showing the configuration of a rotor according to the tenth embodiment, and schematically shows a cross-section cut along a plane that passes through the axis 10A of the rotating electric machine 1. In this embodiment, as in the ninth embodiment, the rotor 230 has a single configuration in the axial direction.

[0099] 27 , the rotor 230 includes, for each pole, a first permanent magnet 22A disposed at a leading position in the forward rotation direction (arrow 60) of the rotor 230, a second permanent magnet 22B disposed at a lagging position, and a first through hole 55B and a second through hole 55C through which the fluid 51 flows. The first permanent magnet 22A and the second permanent magnet 22B are disposed symmetrically or approximately symmetrically with respect to the d axis d0 of the rotor 230. The first through hole 55B is disposed on the first permanent magnet 22A side with respect to the d axis d0 of the rotor 230, and the second through hole 55C is disposed on the second permanent magnet 22B side with respect to the d axis d0 of the rotor 230.

[0100] The first through hole 55B and the second through hole 55C are arranged symmetrically or approximately symmetrically with respect to the d-axis d0 of the rotor 230. The fluid 51 for cooling the rotor 230 flows through the first through hole 55B and the second through hole 55C in the same axial direction, but the speed at which the fluid flows through the first through hole 55B is set to be greater than the speed at which the fluid flows through the second through hole 55C. The first permanent magnet 22A generates more heat than the second permanent magnet 22B, so that the first permanent magnet 22A is a high-heat-generating magnet and the second permanent magnet 22B is a low-heat-generating magnet.

[0101] In this embodiment, a first permanent magnet 22A and a second permanent magnet 22B are provided on each pole of the rotor 230, and a first through hole 55B and a second through hole 55C are provided for each pole to allow the fluid 51 to flow in the axial direction. The flow velocity of the fluid 51 flowing in the axial direction through the first through hole 55B is set to be higher than the flow velocity through the second through hole 55C. Specifically, the fluid 51 flows at high speed through the first through hole 55B, which is located near the first permanent magnet 22A (high-heat-generating magnet) that generates a high amount of heat, and flows at low speed through the second through hole 55C, which is located near the second permanent magnet 22B (low-heat-generating magnet) that generates a low amount of heat.

[0102] Because heat transfer from a solid to a fluid increases as the flow velocity increases, the heat generated by the first permanent magnet 22A is more likely to escape into the fluid 51 than the heat generated by the second permanent magnet 22B, and the heat dissipation ability of the first permanent magnet 22A is greater than that of the second permanent magnet 22B. In this way, the first permanent magnet 22A, which generates a greater amount of heat, can dissipate heat more effectively than the second permanent magnet 22B, which generates a smaller amount of heat, making it possible to uniformly distribute the temperature of the rotor 230 and reduce the maximum temperature, thereby enabling the rotating electric machine 1 to be made smaller and with higher output.

[0103] Furthermore, in this embodiment, the rotor 230 can be made symmetrical with respect to the d-axis d0, which makes it easy to design the magnetic circuit.

[0104] The method for setting the positions of the first and second through holes 55B and 55C is not limited as long as they are symmetrical with respect to the d-axis d0 of the rotor 230. For example, flux barriers on the magnetic circuit can be used as the first and second through holes 55B and 55C.

[0105] Although the above-described tenth embodiment has been described as a rotating electric machine 1 serving as a drive motor primarily performing power running, the present invention can also be applied to a rotating electric machine 1 serving as a generator primarily performing regenerative operation. In this case, the second permanent magnet 22B is a high-heat-generating magnet, and the first permanent magnet 22A is a low-heat-generating magnet. The flow velocity of the fluid 51 flowing in the axial direction through the second through-hole 55C is set to be greater than the flow velocity through the first through-hole 55B. That is, the fluid 51 flows at a high speed through the second through-hole 55C located near the second permanent magnet 22B (high-heat-generating magnet) with a high heat generation rate, and at a low speed through the first through-hole 55B located near the first permanent magnet 22A (low-heat-generating magnet) with a low heat generation rate. This allows the second permanent magnet 22B with a high heat generation rate to dissipate heat more efficiently than the first permanent magnet 22A with a low heat generation rate. This allows the temperature distribution of the rotor 230 to be uniform, reducing the maximum temperature and enabling the rotating electric machine 1 to be made smaller and with higher output.

[0106] Furthermore, in this embodiment, as will be described below, the rotating electric machine 1 may be provided with a flow rate switch 9 that switches the flow rate of the fluid 51. Fig. 28 is a block diagram showing the system configuration of an electric vehicle according to another example of embodiment 10. As shown in Fig. 28, an electric vehicle 100B includes a rotating electric machine 1, a rotation sensor 2, an inverter 3, a battery 4, and further a flow rate switch 9 provided in the rotating electric machine 1. The flow rate switch 9 reverses the magnitude relationship between the speed of the fluid 51 flowing through the first through hole 55B and the speed of the fluid 51 flowing through the second through hole 55C when the rotating electric machine 1 switches between powering operation and regenerative operation.

[0107] When the drive condition of the rotating electric machine 1 changes from powering to regeneration, the inverter 3 provides a switching command 3a to the flow rate switch 9, which reduces the flow rate of the fluid 51 through the first through hole 55B and increases the flow rate through the second through hole 55C. That is, the flow rate switch 9 switches the flow rate so that the flow rate of the fluid 51 through the first through hole 55B is slower than the flow rate through the second through hole 55C. When the rotating electric machine 1 is powering, the first permanent magnet 22A generates more heat, and when the rotating electric machine 1 is regenerating, the second permanent magnet 22B generates more heat. In this case, since the flow rate switch 9 is provided in the rotating electric machine 1, the rotor 230 can be effectively cooled not only during powering but also during regeneration.

[0108] In this way, by providing the flow rate switch 9, the rotor 230 can be cooled effectively during both power running and regeneration operations, so that the rotor 230 can be cooled equally effectively whether the main operation of the rotating electric machine 1 is power running, regeneration, or both operations to the same extent.

[0109] In the first embodiment described above, an inner rotor type rotating electric machine 1 having a stator 30 on the outside of the rotor 20 is shown, but each of the first to tenth embodiments may use an outer rotor type rotating electric machine as shown in Fig. 29, and similar effects can be obtained. Fig. 29 is a cross-sectional view showing the schematic configuration of a rotating electric machine 1A, and shows a cross section cut along a plane passing through the axis of the rotating electric machine 1A.

[0110] As shown in the figure, the rotating electric machine 1A includes a cylindrical shaft 10, a cylindrical rotor 20, and a cylindrical stator 30 disposed inside the rotor 20 with a gap therebetween. The rotor 20 and the stator 30 are disposed with an axis 10A coaxial with each other. The shaft 10 is rotatably supported by a bearing 41, which is fitted into a bracket 42, and the bracket 42 is fastened to a housing 43 by fastening elements such as screws. The stator 30 is an armature including a stator core 31 and coils 32 wound around each tooth (not shown) of the stator core 31.

[0111] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this application. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0112] REFERENCE SIGNS LIST 1, 1A Rotating electric machine, 3 Inverter, 5 Flow path switch, 6 Rotating electric machine unit, 7 Reducer, 8 Rotating electric machine unit, 9 Flow rate switch, 20 Rotor, 20A First block, 20B Second block, 22A First permanent magnet, 22B Second permanent magnet, 30 Stator, 31 Stator core, 31A Axial end region, 31B Axial central region, 31AA, 31BA, 31BB Teeth portion, 32 Coil, 50 Air, 50A Fluid, 51 Fluid, 55, 55A Through hole, 55B First through hole, 55C Second through hole, 100, 100A, 100B Electric vehicle, 200 Rotor, 200A First block, 200B Second block, 201 Rotor, 210A First block, 210B Second block, 220 Rotor, d0 Rotor d-axis.

Claims

1. In a rotating electrical machine comprising a cylindrical rotor having at least one first permanent magnet and at least one second permanent magnet for each pole, and a cylindrical stator having a stator core and windings and disposed via a gap with respect to the rotor, the first permanent magnet is disposed at a position advanced in the forward rotation direction of the rotor with respect to the d-axis of the rotor, and the second permanent magnet is disposed at a position delayed in the forward rotation direction of the rotor with respect to the d-axis of the rotor, based on the difference in the heat generation levels between the first permanent magnet and the second permanent magnet that generate heat according to the operation of the rotating electrical machine, one of the first and second permanent magnets is defined as a high heat generation magnet and the other as a low heat generation magnet, the rotor is cooled by heat transfer through a fluid with the heat dissipation property of the high heat generation magnet being made greater than that of the low heat generation magnet, rotating electrical machine.

2. The rotor includes a plurality of stages of blocks arranged axially, each stage including at least one first block having the first permanent magnet for each pole and at least one second block having the second permanent magnet for each pole, among the plurality of stages of blocks, the block including the high heat generation magnet is disposed on the axial end side, and the block including the low heat generation magnet is disposed on the axial center side, The rotating electrical machine according to claim 1.

3. The stator core has teeth portions protruding toward the rotor side and is axially laminated, and in the axial end region, at least one of the tip width and the root width of the teeth portion is narrower than that of the teeth portion in the axial center region, The rotating electrical machine according to claim 2.

4. The fluid flows axially to cool the rotor, the rotor includes a first block having the first permanent magnet for each pole and a second block having the second permanent magnet for each pole arranged axially, among the first and second blocks, the block including the high heat generation magnet is disposed on the upstream side of the fluid, and the block including the low heat generation magnet is disposed on the downstream side of the fluid, The rotating electrical machine according to claim 1.

5. The rotor includes through holes penetrating axially for each pole, and the fluid flows through the through holes, The rotating electrical machine according to claim 4.

6. A switch for reversing the direction of flow of the fluid is provided, and the direction of the fluid is reversed when switching between the motoring operation and the regenerative operation of the rotating electrical machine, The rotating electrical machine according to claim 4 or claim 5.

7. The rotor includes through holes that penetrate axially for each pole, and the fluid flows through the through holes to cool the rotor. The through holes are provided at positions where the distance from the through holes to the high heat - generating magnet is shorter than the distance from the through holes to the low heat - generating magnet. The rotating electrical machine according to any one of claims 1 to 4.

8. The rotor includes, for each pole, the first permanent magnet and the second permanent magnet arranged symmetrically with respect to the d - axis. The rotating electrical machine according to claim 7.

9. The rotor includes, for each pole, the first permanent magnet and the second permanent magnet arranged symmetrically with respect to the d - axis, and further includes first through holes and second through holes that penetrate axially for each pole. The fluid flows through the first through holes and the second through holes in the same direction to cool the rotor. The first through holes are located on the first permanent magnet side of the d - axis, and the second through holes are located on the second permanent magnet side of the d - axis, and the first through holes and the second through holes are arranged symmetrically with respect to the d - axis. Among the first and second through holes, the velocity of the fluid flowing through the through hole on the high heat - generating magnet side is greater than the velocity of the fluid flowing through the through hole on the low heat - generating magnet side. The rotating electrical machine according to claim 1.

10. A switch for switching the velocity of the fluid is provided, and when switching between the motoring operation and the regenerative operation of the rotating electrical machine, the magnitude relationship between the velocity of the fluid flowing through the first through hole and the velocity of the fluid flowing through the second through hole is reversed. The rotating electrical machine according to claim 9.

11. The rotating electrical machine is a motor that mainly performs a motoring operation, the high heat - generating magnet is the first permanent magnet, and the low heat - generating magnet is the second permanent magnet. The rotating electrical machine according to any one of claims 1 to 5, claim 9, and claim 10.

12. The rotating electrical machine is a generator that mainly performs a regenerative operation, the high heat - generating magnet is the second permanent magnet, and the low heat - generating magnet is the first permanent magnet. The rotating electrical machine according to any one of claims 1 to 5, claim 9, and claim 10.

13. The rotating electrical machine according to claim 1 and an inverter for driving and controlling the rotating electrical machine are provided. The rotor includes, in the axial direction, a first block including the first permanent magnet for each pole and a second block including the second permanent magnet for each pole. The inverter is disposed on one axial end side of the rotating electrical machine, on the side closer to the block including the low heat - generating magnet among the first and second blocks. Rotating electrical machine unit.

14. A rotating electrical machine unit comprising the rotating electrical machine according to claim 4 or claim 5, and an inverter for driving and controlling the rotating electrical machine, wherein the inverter is disposed on the axial end side on the downstream side of the fluid with respect to the rotating electrical machine. Rotating electrical machine unit.

15. A rotating electrical machine unit comprising the rotating electrical machine according to claim 6, and an inverter connected to the rotating electrical machine, wherein the switch operates by a switching command from the inverter. Rotating electrical machine unit.

16. A rotating electrical machine unit comprising the rotating electrical machine according to claim 10, and an inverter connected to the rotating electrical machine, wherein the switch operates by a switching command from the inverter. Rotating electrical machine unit.

17. A rotating electrical machine unit comprising the rotating electrical machine according to claim 1, and a speed reducer connected to the rotating electrical machine, wherein the rotor includes, in the axial direction, a first block including the first permanent magnet for each pole and a second block including the second permanent magnet for each pole, and the speed reducer is disposed on one axial end side of the rotating electrical machine, on the side closer to the block including the low heat - generating magnet among the first and second blocks. Rotating electrical machine unit.

18. A rotating electrical machine unit comprising the rotating electrical machine according to claim 4 or claim 5, and a speed reducer connected to the rotating electrical machine, wherein the speed reducer is disposed on the axial end side on the downstream side of the fluid with respect to the rotating electrical machine. Rotating electrical machine unit.

19. The rotating electrical machine is a motor mainly performing power running operation, the high heat - generating magnet is the first permanent magnet, and the low heat - generating magnet is the second permanent magnet. Rotating electrical machine unit according to any one of claims 13, 16, and 17.

20. The rotating electrical machine is a generator mainly performing regenerative operation, the high heat - generating magnet is the second permanent magnet, and the low heat - generating magnet is the first permanent magnet. Rotating electrical machine unit according to any one of claims 13, 16, and 17.

21. In an electric vehicle driven by comprising the rotating electrical machine according to any one of claims 1 to 5, 9, and 10, wherein the forward rotation of the rotor is the main rotation direction, which is the rotation direction when the electric vehicle moves forward. Electric vehicle.