Rotary electric machine and method for manufacturing rotary electric machine

Abstract

This rotary electric machine (100) comprises a rotor (300) which has: a rotor core (311); and a plurality of permanent magnets (321) embedded in the circumferential direction on the outer peripheral part side of the rotor core (311), wherein a shaft (400) is press-fitted in the inner peripheral part of the rotor (300). The rotor (300) includes: flux barrier parts (331a) at both ends of the permanent magnets (321) in the circumferential direction; and openings (311d, 311g, 410g) between the shaft (400) and bridge parts (331b) disposed between the flux barrier parts (331a) of adjacent permanent magnets.

Description

Rotating electric machine and method of manufacturing the same

[0001] The present disclosure relates to a rotating electric machine and a method for manufacturing the rotating electric machine.

[0002] For reasons such as reducing manufacturing costs and improving assembly, conventional rotors for rotating electrical machines have adopted a structure in which a shaft is press-fitted into a laminated iron core (rotor core) equipped with permanent magnets, and the laminated iron core is fixed to the outer periphery of the shaft (see, for example, Patent Document 1).

[0003] JP 2012-100477 A

[0004] In conventional rotors for rotating electric machines, when a shaft is press-fitted into a laminated core, deformation and displacement are transmitted from the shaft to the laminated core, resulting in a decrease in runout accuracy of the rotor's outer diameter. The decrease in runout accuracy of the rotor's outer diameter leads to an uneven rotor outer diameter, causing vibration and noise throughout the device. Furthermore, the stator is disposed on the outer periphery of the rotor with a gap, but an uneven gap between the stator and rotor reduces magnetic efficiency, resulting in a decrease in output and efficiency of the rotating electric machine. Furthermore, an uneven gap between the stator and rotor leads to an uneven magnetism, resulting in an increase in magnetic noise. Furthermore, the low runout accuracy of the rotor's outer diameter requires a larger gap between the stator and rotor to avoid contact between the stator and rotor, which results in a decrease in magnetic properties, a decrease in output and efficiency of the rotating electric machine, and other issues.

[0005] The present disclosure discloses a technology for solving the above-mentioned problems, and aims to provide a rotating electric machine and a method for manufacturing the rotating electric machine that can suppress a decrease in the outer diameter runout accuracy of the rotor and achieve high output in a rotating electric machine in which a shaft is pressed into a laminated iron core (rotor).

[0006] The rotating electric machine disclosed herein is a rotating electric machine equipped with a rotor having a rotor core and a plurality of permanent magnets embedded circumferentially on the outer periphery of the rotor core, with a shaft pressed into the inner periphery, wherein the rotor has flux barrier portions at both circumferential ends of the permanent magnets, and an opening between the shaft and a bridge portion between the flux barrier portions of adjacent permanent magnets.

[0007] According to the rotating electric machine of the present disclosure, deterioration in the outer diameter runout accuracy of the rotor is suppressed, and it is possible to achieve high output.

[0008] 1 is a cross-sectional view showing the configuration of a rotating electric machine according to a first embodiment. FIG. 2 is an axial cross-sectional view showing the configuration of a rotor of the rotating electric machine according to the first embodiment, showing the A-A cross-section in FIG. 1 . FIG. 3 is an axial cross-sectional view showing the configuration of a rotor of the rotating electric machine according to the first embodiment. FIG. 4 is a view for explaining suppression of outer diameter runout in a rotor core according to the first embodiment. FIG. 5 is a view for explaining suppression of outer diameter runout in a rotor core according to the first embodiment. FIG. 6 is an axial cross-sectional view showing the configuration of a rotor of the rotating electric machine according to the first embodiment, showing the radial thickness of the rotor core. FIG. 7 is an enlarged cross-sectional view of a part of a rotor according to a first modified example of the first embodiment. FIG. 8 is an enlarged cross-sectional view of a part of a rotor according to the first modified example. FIG. 9 is an enlarged cross-sectional view of a rotor according to the second modified example of the first embodiment. FIG. 10 is an enlarged cross-sectional view of a rotor according to the second modified example of the first embodiment.

[0009] The present embodiment will be described below with reference to the drawings, in which the same reference numerals indicate the same or corresponding parts.

[0010] Embodiment 1. A rotating electric machine according to embodiment 1 will now be described with reference to the drawings. <Configuration of rotating electric machine> Fig. 1 is a diagram showing the configuration of a rotating electric machine according to embodiment 1, and is a cross-sectional view taken along a plane along the axial direction of the rotating shaft. The rotating electric machine is surrounded by a housing 210 having a cylindrical frame 211 with a bottom and an end plate 212 that closes the opening of the frame 211.

[0011] A stator 220 is fixed to the cylindrical portion of the frame 211 and fitted therein. The stator 220 is also called a stator. A rotor 300 is rotatably supported by the bottom portion of the frame 211 and an end plate 212 via bearings 500. The rotor 300 is also called a rotor. The rotor 300 is disposed on the inner periphery of the stator 220.

[0012] The stator 220 includes a plurality of coils 221 that generate magnetic flux, a connection plate 222 that distributes current to the plurality of coils 221, and a stator core 223 that allows the magnetic flux to pass through. The stator 220 has a coil 221 for each of a plurality of phases, and power is supplied to each phase from the connection plate 222 provided for each phase. FIG. 1 illustrates the case of a rotating electric machine 100 having three-phase coils 221. However, the technology described in this specification can also be applied to two-phase rotating electric machines and rotating electric machines with four or more phases. The coils 221, connection plate 222, and stator core 223 are each fixed and electrically insulated by bobbins 224, which are insulators.

[0013] The rotor 300 is arranged with a magnetic gap between it and the stator 220, and includes a rotor core 311 made of laminated electromagnetic steel sheets, and permanent magnets 321 embedded in magnet accommodating holes, which are through-holes provided on the outer periphery of the rotor core 311. The permanent magnets 321 are arranged at a preset pitch in the circumferential direction to form magnetic poles, and are structurally fixed between the permanent magnets 321 and the rotor core 311 by, for example, using a silicone resin adhesive that is heated and hardened.

[0014] A rotor core 311 is disposed on the outer periphery of a cylindrical rotary holder 400 that constitutes the rotor shaft, and the rotary holder 400 is structurally connected to the rotor 300 and extends in the direction of the rotation axis. The rotary holder 400 is rotatably supported by a bearing 500 provided in the housing 210.

[0015] With the above configuration, the ratio of the diameter of the rotary holder 400 to the outer diameter of the rotor core 311 is high, and the thickness of the rotor core 311 in the radial direction of the rotating shaft is thinner than the diameter of the rotary holder 400. This configuration reduces the amount of electromagnetic steel sheet used to make up the rotor core 311, contributing to cost reduction. Furthermore, the rotary holder 400 that holds the rotor core 311 has a configuration that is advantageous for weight reduction, for example, by providing a hollow space between the rotating shaft and the cylindrical rotary holder 400.

[0016] 1 shows an example of a configuration in which the rotary holder 400 that holds the rotor core 311 is rotatably supported directly by the bearing 500. Without being limited to this, for example, the rotary holder 400 may be configured as a cylinder having an internal cavity, and a shaft (not shown) having a smaller diameter than the rotary holder 400 may be separately provided at the position of the rotation axis through the cavity, and this shaft may be rotatably supported by the bearing 500. Furthermore, the rotary holder 400 and the shaft may be integrally connected via a connecting member (not shown) extending in the radial direction, thereby forming a rotary holder member that holds the rotor core 311. In other words, in this specification, the shaft that holds the rotor core 311 is broadly defined to include the rotary holder 400 that holds the rotor core 311 as in the above-described exemplary configuration.

[0017] In this way, even when the interior of rotary holder 400 is hollow and a shaft is provided, the provision of space between the shaft and rotary holder 400 makes it possible to achieve a configuration advantageous for weight reduction, similar to the configuration shown in Fig. 1. Furthermore, mechanical components such as a speed change mechanism or torque transmission device can be incorporated into the hollow portion of rotary holder 400, which is space-efficient and can reduce the overall size of a vehicle when used as a vehicle drive unit, for example.

[0018] Furthermore, even when a configuration in which such a cylindrical rotary holder 400 and a small-diameter shaft are integrally connected via a connecting member extending in the radial direction is used, the radial thickness of the rotor core 311 is reduced. In other words, the ratio of the inner diameter of the rotor core 311 to the outer diameter of the rotor core 311 is significantly greater than half. Therefore, the influence of deviations from the outer diameter of the rotary holder 400 and the circularity of the rotor core 311 when the cylindrical rotary holder 400 is press-fitted into the rotor core 311 is easily transmitted directly to the outer diameter of the rotor core 311. Therefore, this configuration also reduces the radial thickness of the rotor core 311, and is a configuration that is more likely to exhibit the effect of suppressing runout in the outer diameter described in this specification, as will be described later.

[0019] <Suppression of Outer Diameter Runout of Rotor Core 311> Next, a specific example of suppressing outer diameter runout of rotor core 311 when rotary holder 400, which is a shaft, is press-fitted into rotor core 311 will be described with reference to the drawings. Fig. 2 is an axial cross-sectional view showing the configuration of rotor 300 of rotating electric machine 100 according to embodiment 1, showing cross section A-A in Fig. 1. Fig. 3 is an enlarged view of region B in Fig. 2, showing a partial cross-sectional view of rotor 300. Note that hatching has been partially omitted in the subsequent axial cross-sectional views to avoid complication.

[0020] In FIG. 2 , the rotary holder 400 is press-fitted into the rotor core 311, and the rotor core 311 is fixed to the outer periphery of the boss portion 410 of the rotary holder 400. As shown in FIG. 3 , the rotor core 311 has magnet accommodating holes 311a formed on the outer periphery, with permanent magnets 321 embedded therein with adhesive 321a. When the permanent magnets 321 are fixed to the outer periphery of the magnet accommodating holes 311a with adhesive 321a, gaps 311f are formed on the inner periphery (shaft side) of the magnet accommodating holes 311a. As described above, the permanent magnets 321 are arranged at equal intervals in the circumferential direction at a predetermined pitch. Openings 311d are formed between the flux barrier portions 331a at both longitudinal ends of the permanent magnets 321, i.e., at both circumferential ends, and the bridge portions 331b between the flux barrier portions 331a of adjacent permanent magnets 321, and the shaft, so as to radially sandwich the crimped portions 311e. In other words, an opening 311d is formed between adjacent permanent magnets 321 and boss portion 410. This opening 311d penetrates rotor core 311 in the axial direction.

[0021] 3, the openings 311d are, for example, elliptical in shape with a minor axis in the radial direction and a major axis perpendicular to the radial direction or in the circumferential direction. That is, the openings 311d are flattened in a direction perpendicular to the radial direction. The openings 311d are provided at positions corresponding to the bridge portions 331b, i.e., between adjacent permanent magnets 321, and are therefore arranged in rotational symmetry at equal intervals around the circumferential direction of the rotor core 311 at an angle corresponding to the number of magnetic poles.

[0022] When the rotary holder 400 having the boss portion 410 is press-fitted into the rotor core 311 provided with the openings 311d, the openings 311d are crushed in the radial direction, thereby blocking the pressure from the boss portion 410 from being transmitted to the outer periphery, thereby suppressing runout of the outer diameter. In particular, by providing a plurality of openings 311d in a rotationally symmetrical arrangement around the circumferential direction of the rotor core 311, runout of the outer diameter can be further suppressed.

[0023] Furthermore, by forming the opening 311d so as to penetrate in the axial direction, the weight of the rotor core 311 can be reduced. The opening 311d can also be used as a cooling water or oil passage. The distortion of the opening 311d due to pressure from the boss portion 410 is less than a few percent in the radial direction, so there is almost no impact on the refrigerant passage. Furthermore, because the opening 311d is an elliptical opening that is flattened perpendicular to the radial direction, it is easily crushed in the radial direction by pressure from the radial direction, which significantly suppresses the vibration of the outer diameter. The rotating shaft radial V-shaped crimped portion 361 is located inside the permanent magnet 321 in the rotating shaft radial direction. The rotating shaft radial V-shaped crimped portion 361 will be described later.

[0024] Next, the effect of the opening 311d will be described in more detail. Figures 4A and 4B are diagrams illustrating how outer diameter runout is suppressed in the rotor core 311 having the opening 311d formed therein. Figure 4A is a diagram showing the outer diameters R1 and R2 at different locations on the rotor core 311 and the outer diameters D1 and D2 of the press-fit boss portion 410 in Figure 2. Figure 4B is a simplified diagram illustrating the opening 311d in Figure 3 as a single diagram to explain the effect of the opening 311d. The distortion of the inner diameter of the rotor core 311 due to pressure from the boss portion 410 is shown as d2, the distortion at the opening 311d as w1, and the distortion of the outer diameter of the rotor core 311 as d1 are shown. In Figure 4B, the opening 311d is formed, and when the shaft is press-fitted, the opening 311d collapses and distorts, absorbing the pressure from the boss portion 410. Therefore, it can be seen that the distortion d1 of the outer diameter of the rotor core 311 is reduced by the distortion w1 at the opening 311d.

[0025] Here, consider the case where the boss portion 410 has a large circularity. For example, in FIG. 4A , if the difference between the outer diameters D1 and D2 of the boss portion 410 is large, i.e., D1 > D2, the strain d2_D1 of the rotor core 311 corresponding to the portion with the relatively large outer diameter D1 will be larger than the strain d2_D2 corresponding to the portion with the outer diameter D2. However, the strain w1_D1 corresponding to the radial width of the opening 311d corresponding to the outer diameter D1 of the boss portion 410 is relatively larger than the strain w1_D2 corresponding to the radial width of the opening 311d corresponding to the outer diameter D2, which acts to average out the strain d1 transmitted to the outer diameter portion of the rotor core 311. As a result, the difference between the outer diameters R1 and R2 of the rotor core 311 is smaller than the difference between the outer diameters D1 and D2 of the boss portion 410, and the rotor core 311 will have a smaller circularity than the boss portion 410 into which it is press-fitted, becoming closer to a perfect circle. As a result, outer diameter runout is suppressed.

[0026] For example, if the outer diameter of the outer periphery of the shaft, including the outer periphery of the boss portion 410, is distorted by 1%, when the shaft is pressed into the rotor core 311 of this embodiment, the distortion of the outer diameter at the outer periphery of the rotor core 311 will be less than 1%.

[0027] Next, regarding the rotor 300 of the rotating electric machine 100 according to the first embodiment, the effects obtained by configuring the rotor core 311 to have a relatively thin thickness in the radial direction will be described. FIG. 5 is a cross-sectional view taken along the rotational axis direction of the rotor 300 in the rotating electric machine 100 according to the first embodiment. The rotor core 311 is configured by laminating electromagnetic steel sheets punched into a predetermined shape, but the rotor core 311 is prone to eddy current loss due to residual stress generated when punching the electromagnetic steel sheets and a decrease in insulation between the laminations. Therefore, in order to reduce the influence of magnetic characteristics, the V-shaped crimped portion 361 in the radial direction of the rotation shaft is positioned inside the permanent magnet 321 in the radial direction of the rotation shaft.

[0028] When outermost diameter portion 902 of rotor core 311 is φa and innermost diameter portion 903 of rotor core 311 is φb, the thickness of rotor core 311 in the radial direction of the rotation shaft satisfies the following formula: (φa - φb) / 2 ≦ 0.1 × φa In other words, the thickness of rotor core 311 in the radial direction of the rotation shaft is 10% or less of outermost diameter portion 902.

[0029] Furthermore, when the diameter 904 of the rotation holder inner cylindrical portion 420 of the rotation holder 400 is φc, the thickness of the rotation holder 400 in the radial direction of the rotation shaft satisfies the following formula: (φb−φc) / 2≦0.1×φa In other words, the thickness of the rotation holder 400 in the radial direction of the rotation shaft is 10% or less of the outermost diameter portion 902 of the rotor core 311.

[0030] In a configuration in which the radial thickness of rotor core 311 in the rotational shaft direction is 10% or less of outermost diameter portion 902, as in the present embodiment, this corresponds to a configuration in which rotor core 311 has a relatively thin radial thickness. The same applies to a configuration in which cylindrical rotary holder 400 and a small-diameter shaft are integrally connected via a connecting member extending in the radial direction, in which the radial thickness of rotor core 311 in the rotational shaft direction is 10% or less of outermost diameter portion 902, i.e., corresponds to a configuration in which rotor core 311 has a relatively thin radial thickness. Therefore, a configuration in which rotor core 311 has a relatively thin radial thickness makes it easier for the influence of deviations from the outer diameter of rotary holder 400 and the roundness of rotor core 311 to be transmitted directly to the outer periphery of rotor core 311, and therefore this is one of the configurations in which opening 311d in the present embodiment is more effective in improving runout in the outer diameter.

[0031] Furthermore, in a configuration in which the radial thickness of the rotary holder 400 in the rotational shaft direction is 10% or less of the outermost diameter portion 902 of the rotor core 311, as in the present embodiment, this corresponds to a configuration in which the radial thickness of the rotary holder 400 is relatively thin. In this configuration, it is expected that the strength of the cylindrical member will decrease, and the circularity of the outer diameter of the rotary holder will increase, i.e., the deviation from a perfect circle will become relatively large. Therefore, this is one of the configurations in which the opening 311d in the present embodiment is more effective in improving the runout of the outer diameter. Furthermore, the configuration in which the radial thickness of the rotary holder 400 is relatively thin is a common feature also in a configuration in which the cylindrical rotary holder 400 and a small-diameter shaft are integrally connected via a connecting member extending in the radial direction, and therefore the above-mentioned effect can be similarly achieved in this configuration.

[0032] Note that a configuration in which the radial thickness of the rotating holder 400 or the radial thickness of the rotating holder 400 is 10% or less of the outermost diameter portion 902 of the rotor core 311 has been described as a suitable example in which the effect of this embodiment can be exerted. However, if the radial thickness of the rotor core 311 or the radial thickness of the rotating holder 400 is relatively thin, the effect of this embodiment can be exerted to varying degrees, and if the radial thickness of the rotating holder 400 is 30% or less of the outermost diameter portion 902 of the rotor core 311, it is expected that the effect expected in this embodiment can be obtained.

[0033] Next, the effect of the configuration shown in FIG. 3 , in which openings 311d are formed between bridge portion 331b and the shaft so as to sandwich crimped portion 311e in the radial direction, will be described. Crimped portion 311e functions to secure the laminations of the electromagnetic steel sheets that make up rotor core 311 together in the axial direction. While crimping between laminations is a commonly known construction method, the load applied during crimping can worsen runout of the outer diameter. However, in this embodiment, two openings 311d that are flattened perpendicular to the radial direction are provided and positioned so as to sandwich crimped portion 311e in the radial direction, thereby effectively reducing the effect on runout of the outer diameter caused by the load applied during crimping.

[0034] Also, as shown in Figure 3, in the rotor 300 of this embodiment 1, the permanent magnet 321 is fixed inside the magnet accommodating hole 311a of the rotor core 311 on the outer periphery side by adhesive 321a, and a gap portion 311f is formed on the inner periphery side (shaft side) of the magnet accommodating hole 311a.

[0035] Furthermore, a rotational shaft radial V crimping portion 361 is provided in a range sandwiched between the permanent magnets 321 of the rotor core 311 and the shaft. The rotational shaft radial V crimping portion 361 may be disposed at a position on the inner periphery of all of the permanent magnets 321, but is not required to be disposed at a position on the inner periphery of all of the permanent magnets 321. Because of concerns about the effects that may be caused by disposing the rotational shaft radial V crimping portion 361, in the first embodiment, the rotational shaft radial V crimping portion 361 is disposed at every other position of the permanent magnets 321 arranged in the circumferential direction. In other words, the positions where the rotational shaft radial V crimping portion 361 is provided and where it is not provided are arranged alternately.

[0036] Furthermore, there is a concern that the influence of the pressure from boss portion 410 when the shaft is press-fitted into rotor core 311 will be transmitted to some extent to the outer periphery of rotor core 311, even in the region where permanent magnet 321 is arranged. However, in rotor 300 of the first embodiment, gap 311f is formed on the inner periphery of magnet accommodating hole 311a, so that the influence of the pressure from boss portion 410 is suppressed so as not to affect the outer diameter runout of rotor core 311. This has the same effect as opening 311d provided between bridge portion 331b and the shaft. Furthermore, gap 311f also has the effect of mitigating distortion that occurs when rotary shaft radial V-shaped crimped portion 361 is formed.

[0037] Below, we will explain modified examples that are partially different from the configuration shown in FIG. 3 of the first embodiment. In these modified examples, we will mainly explain the modified parts, and omit explanations of common parts as appropriate. Furthermore, in the drawings used for explanation, the modified parts are shown in detail, but the common parts are not shown in detail. For example, the magnet accommodating holes 311a are simply shown as rectangles, and the flux barrier portions 331a arranged at both longitudinal ends of the permanent magnets 321 are not shown. However, each magnet will have a flux barrier portion 331a similar to the flux barrier portion 331a shown in FIG. 3 at both longitudinal ends, and a bridge portion 331b will be formed in the area sandwiched between the flux barrier portions 331a of adjacent permanent magnets 321.

[0038] <Modification 1> FIGS. 6A and 6B are partially enlarged cross-sectional views of a rotor 300 according to Modification 1 of Embodiment 1, illustrating the openings 311d of the rotor core 311. In FIG. 3, the openings 311d disposed between the bridge portion 331b and the shaft are elliptical openings flattened in a direction perpendicular to the radial direction. Two openings 311d are arranged radially, sandwiching the crimped portion 311e. As long as the openings penetrate the rotor axially and flatten in a direction perpendicular to the radial direction, they may be rectangular openings 311d with their longitudinal direction perpendicular to the radial direction, as shown in FIG. 6A. Alternatively, as shown in FIG. 6B, they may be triangular openings 311d with obtuse angles in the radial direction. These openings 311d are easily crushed in the radial direction by radial pressure, thereby suppressing external diameter runout. Furthermore, the openings 311d are not necessarily limited to a shape flattened in a direction perpendicular to the radial direction. For example, they may be circular openings. Even with a circular opening, a certain level of external diameter runout suppression effect can be achieved.

[0039] 3, the crimped portions 311e are arranged so as to sandwich the crimped portions 311e in the radial direction, but the various openings 311d described above may be arranged between the bridge portion 331b and the shaft regardless of whether or not crimped portions are arranged. Furthermore, the number of openings 311d may be multiple or one. When multiple openings 311d are provided, the same effect can be achieved even if openings 311d of different shapes are arranged between the bridge portion 331b and the shaft.

[0040] 7A and 7B are enlarged cross-sectional views of a portion of a rotor 300 according to a second modification of the first embodiment. As shown in Fig. 7A, an opening 311g disposed between the bridge portion 331b and the shaft is formed between the bridge portion 331b and the shaft by a recess cut out in the axial direction through the inner periphery of the rotor core 311. Even with this configuration, the influence of the pressure of the boss portion 410 when the boss portion 410 is press-fitted into the rotor core 311 can be suppressed from being transmitted to the outer periphery of the rotor core 311. This additionally makes it possible to reduce stress generated between the bridge portion 331b and the shaft.

[0041] Furthermore, the recess cut in the axial direction may be formed on the shaft side. As shown in FIG. 7B , a groove or recess may be provided along the axial direction on the outer periphery of the boss portion 410 extending from the bridge portion 331b toward the shaft, forming an opening between the bridge portion 331b and the rotor core 311, forming opening 410g between the bridge portion 331b and the shaft. By providing an opening at the contact point between the rotor core 311 and the boss portion 410 (shaft) in this manner, the same effect as in the first embodiment described above can be achieved. Note that, in FIGS. 7A and 7B , tapering the opening side from the bottom can further reduce stress.

[0042] <Modification 3> Figure 8 is a partially enlarged cross-sectional view of a rotor 300 according to Modification 3 of Embodiment 1, illustrating the opening 311d of the rotor core 311. In Figure 3, two elliptical openings 311d that are flattened perpendicular to the radial direction are provided between the bridge portion 331b and the shaft, and are arranged so as to sandwich the crimped portion 311e in the radial direction. In Modification 3, as shown in Figure 8, flat U-shaped openings 311d are arranged facing each other and surrounding the crimped portion 311e except for a portion of the crimped portion 311e in the longitudinal direction. In this way, by arranging the openings 311d so as to substantially surround the periphery of the crimped portion 311e, it is possible to more significantly reduce the influence of outer diameter runout caused by the load during crimping. Note that this flat U-shaped opening 311d is an example of an opening that penetrates in the axial direction and is flattened perpendicular to the radial direction.

[0043] 9A and 9B are partially enlarged cross-sectional views of a rotor 300 according to a fourth modification of the first embodiment, illustrating the opening 311d of the rotor core 311. In the third modification described above, the flat U-shaped opening 311d is disposed between the bridge portion 331b and the shaft, facing each other, and surrounding the crimped portion 311e except for a portion of the crimped portion 311e in the longitudinal direction. As shown in FIG. 9A , the opening 311d shown in the third modification may also be disposed in the radial V-shaped crimped portion 361 of the rotating shaft provided on the inner periphery of the permanent magnet 321. In this way, in the region between the permanent magnet 321 and the shaft, the opening 311d, together with the gap 311f provided on the inner periphery of the permanent magnet 321, can also reduce the influence of outer diameter runout caused by the load during crimping of the radial V-shaped crimped portion 361 of the rotating shaft.

[0044] 9B is a diagram showing an example in which flat U-shaped openings 311d are arranged to face both crimped portion 311e between bridge portion 331b and the shaft and rotation shaft radial V crimped portion 361 provided on the inner peripheral side of permanent magnet 321, and surround the crimped portions. That is, it is a diagram showing an example combining FIGS. 8 and 9A. By arranging openings 311d in this way, the influence of outer diameter runout caused by the load during crimping of all crimped portions arranged on rotor core 311 can be reduced over the entire circumference, contributing to uniformity of the outer diameter of rotor core 311.

[0045] In the first embodiment and the first to third variations, a configuration was described in which an opening or crimped portion 311e and an opening sandwiching it at least radially were provided between the bridge portion 331b and the shaft. However, as shown in the fourth variation, the openings shown in the first embodiment and the first to third variations may also be arranged on the inner circumferential side of the permanent magnet 321.

[0046] In particular, in order to prevent the influence of the rotating shaft radial V-shaped crimped portion 361 on the inner periphery of the permanent magnet 321 on the outer diameter runout, it is desirable to provide an opening so as to radially sandwich the rotating shaft radial V-shaped crimped portion 361. Utilizing the gap 311f on the inner periphery (shaft side) of the magnet accommodating hole 311a that is already provided, an opening may be arranged so that the rotating shaft radial V-shaped crimped portion 361 is radially sandwiched between this gap 311f and the opening. As described above, this configuration can reduce the influence of the outer diameter runout caused by the load during crimping of all crimped portions arranged on the rotor core 311 over the entire circumference, contributing to uniformity of the outer diameter of the rotor core 311.

[0047] <Modification 5> In the configuration shown in FIG. 3 in which two elliptical openings 311d flattened in a direction perpendicular to the radial direction are provided, and in the configurations of the openings 311d having other shapes shown in Modifications 1 to 4, openings 311d of essentially the same shape are provided between the bridge portions 331b sandwiched between the flux barrier portions 331a of adjacent permanent magnets 321 and the shaft, and are arranged rotationally symmetrically in the circumferential direction. This is effective in suppressing runout of the outer diameter of the rotor core 311. However, this is not limited to this. For example, two types of openings 311d of different shapes may be arranged alternately in the circumferential direction between each bridge portion 331b and the shaft. This basically rotationally symmetric arrangement is effective in reducing runout of the outer diameter.

[0048] Furthermore, openings of different shapes may be arranged between one bridge portion 331b and the shaft, and this shape may be applied around the entire circumference between another bridge portion 331b and the shaft. For example, it is possible to arrange elliptical openings 311d and rectangular openings 311d together, or to arrange elliptical openings 311d and openings 311g formed by recesses cut axially through the inner periphery of rotor core 311. By arranging gaps of different shapes together, it is expected that the effects of each opening shape can be combined to produce a synergistic effect.

[0049] <Manufacturing Method of Rotating Electric Machine 100> Next, a manufacturing method of the rotating electric machine 100 according to the first embodiment will be described, focusing on the manufacturing process of the rotor 300. FIG. 10 is a diagram showing the rotor manufacturing process in the manufacturing method of the rotating electric machine according to the first embodiment. Although not shown, this process includes the following preparation process of the rotor core 311. Electromagnetic steel sheets punched into a predetermined shape are stacked and integrated by caulking to form the rotor core 311. The rotor core 311 also has an opening 311d penetrating in the axial direction and a magnet accommodating hole 311a. An adhesive 321a is applied to the magnet accommodating hole 311a, and a permanent magnet 321 is inserted therein.

[0050] The shaft is press-fitted into the rotor core 311, and the boss portion 410 of the shaft and the rotor core 311 are fixed together (shaft press-fitting process). Next, the permanent magnets 321 arranged in the magnet accommodating holes 311a, which penetrate the rotor core 311 in the axial direction, are bonded with adhesive 321a at least on the outer periphery of the magnet accommodating holes 311a, and the adhesive 321a is thermally cured using a heat source such as a heater 20 to fix the permanent magnets 321 (adhesive curing process). Next, the permanent magnets 321 are magnetized using a magnetizer 30 (magnetizing process), and the rotor 300 fixed to the shaft is completed. Although not shown, a separately manufactured stator 220 is attached to the outer periphery of the rotor, and the rotor 300 is assembled together with the housing 210 to complete the rotating electric machine 100.

[0051] A distinctive feature of the manufacturing method for rotor 300 according to the first embodiment is that the rotor is manufactured in the following order: shaft press-fitting process, adhesive curing process, and magnetization process. The other processes, including the assembly process of the stator, etc., may be in the order of conventional, well-known manufacturing processes. When permanent magnets 321 are magnetized, the outer diameter of rotor core 311 changes due to the influence of magnetic force, resulting in runout of the outer diameter. By performing magnetization after the magnets are inserted and after the adhesive for the magnets has cured, the magnets can be stably positioned on the outer diameter side, suppressing runout of the outer diameter, resulting in a rotating electric machine with stable, high output.

[0052] As described above, the rotating electric machine according to the first embodiment is a rotating electric machine including a rotor having a rotor core and a plurality of permanent magnets embedded circumferentially on the outer periphery side of the rotor core, with a shaft press-fitted into the inner periphery, and the rotor is provided with flux barrier portions at both circumferential ends of the permanent magnets, and an opening is provided between the shaft and the bridge portion between the flux barrier portions of adjacent permanent magnets. Therefore, distortion caused when the shaft is press-fitted into the rotor core is prevented from being transmitted to the outer diameter of the rotor core by the opening being crushed and deformed in the radial direction, thereby suppressing outer diameter runout. By suppressing outer diameter runout of the rotor core, a decrease in accuracy of outer diameter runout is suppressed, and a rotating electric machine with high output can be obtained.

[0053] Second Embodiment A rotating electric machine according to the second embodiment will now be described with reference to the drawings. Fig. 11 is a partially enlarged axial cross-sectional view of a rotor 300 of a rotating electric machine according to the second embodiment. In the first embodiment, the permanent magnets 321 arranged in the magnet accommodating holes 311a of the rotor core 311 are fixed at the outer periphery of the magnet accommodating holes 311a with adhesive 321a, and gaps 311f are formed between the permanent magnets 321 and the inner periphery of the magnet accommodating holes 311a. In the second embodiment, as shown in Fig. 11, the magnet accommodating holes 311a are filled with adhesive 321a, and gaps 311f are not formed.

[0054] In this way, when magnet accommodating hole 311a is filled with adhesive 321a, the adhesive has hardened, and there is nothing to suppress the effects (distortion) caused by the press-fitting of boss portion 410, so the distortion is easily transmitted to the outer diameter of rotor core 311, causing outer diameter runout. Here, for example, flat U-shaped opening 311d shown in Figure 9A is arranged to face each other and surround the crimped portion. This reduces the effects of the press-fitting of boss portion 410 on the outer diameter runout of rotor core 311, making it possible to obtain a rotating electric machine with high output.

[0055] It should be noted that, with reference to the above-described first embodiment and its modifications, similar effects can be achieved even when an opening having a shape other than the flat U-shaped opening 311d shown in Fig. 9A is applied. It goes without saying that the configuration of the second embodiment can also be applied to the configuration shown in the first embodiment in which an opening is provided between the bridge portion 331b sandwiched between the flux barrier portions 331a of adjacent permanent magnets 321 and the shaft.

[0056] As described above, according to the second embodiment, since an opening is provided between the permanent magnet and the shaft, runout of the rotor core can be suppressed not only in the bridge portion but also on the outer diameter side of the permanent magnet. When the magnet accommodating holes are filled with adhesive, distortion caused by press-fitting is likely to be transmitted to the outer diameter of the rotor core. Therefore, by providing an opening, the effect on runout of the outer diameter can be reduced. As in the first embodiment, this suppresses runout of the rotor core's outer diameter, thereby suppressing a decrease in accuracy of runout of the outer diameter, and making it possible to obtain a rotating electric machine with high output.

[0057] Third Embodiment A rotating electric machine according to a third embodiment will now be described with reference to the drawings. Fig. 12 is a partially enlarged, axial cross-sectional view of a rotor 300 of a rotating electric machine according to the third embodiment. In the first embodiment, the permanent magnets 321 arranged in the magnet accommodating holes 311a of the rotor core 311 are fixed at their outer peripheries within the magnet accommodating holes 311a with adhesive 321a, and gaps 311f are formed between the permanent magnets 321 and the magnet accommodating holes 311a on the inner periphery side. In the third embodiment, as shown in Fig. 12, the permanent magnets 321 are fixed at their outer peripheries within the magnet accommodating holes 311a with adhesive 321a on both longitudinal sides, with the central portion left unattached, and gaps 311f are also formed at their outer peripheries.

[0058] Since adhesive 321a shrinks as it hardens, when adhesive is filled between permanent magnets 321 on the outer periphery inside magnet accommodating holes 311a and hardens, the distortion caused by hardening is transmitted to rotor core 311, causing runout in the outer diameter. Therefore, by forming gap 311f in the center between permanent magnets 321 on the outer periphery inside magnet accommodating holes 311a, it is possible to obtain rotating electric machine 100 having rotor 300 with reduced shrinkage caused by adhesive hardening and suppressed runout in the outer diameter.

[0059] As shown in Figure 12, by moving the permanent magnet 321 closer to the outer periphery of the magnet accommodating hole 311a and forming a gap 311f on the inner periphery of the magnet accommodating hole 311a, the permanent magnet 321 is positioned closer to the stator, which is on the outer side, so that a high-performance rotating electric machine can be obtained.

[0060] Although an example has been shown in which the permanent magnet 321 is fixed with adhesive 321a on both longitudinal sides of the outer periphery of the magnet accommodating hole 311a and not glued in the center, this is not limiting. As long as gaps 311f can be formed on the outer periphery of the magnet accommodating hole 311a, adhesive may be applied at multiple locations with intervals. By adjusting the adhesive application position, it is possible to determine the adhesive position and the position where the gap 311f is not to be glued. In other words, in the adhesive curing step shown in FIG. 10 of the first embodiment, the adhesive application position is adjusted and then cured, thereby manufacturing a rotating electric machine similar to that of the first embodiment.

[0061] Furthermore, the permanent magnet 321 may be fixed in a part of the inner periphery of the magnet accommodating hole 311a with adhesive 321a, with a gap 311f formed in the outer periphery, and with a gap 311f formed in the inner periphery that is not bonded. Furthermore, the permanent magnet 321 may be fixed in a part of the outer periphery and a part of the inner periphery of the magnet accommodating hole 311a with adhesive 321a, with a gap 311f formed in the outer periphery and the inner periphery that is not bonded.

[0062] As described above, according to embodiment 3, the same effects as those of embodiment 1 are achieved. Furthermore, the rotor core has magnet accommodating holes in which permanent magnets are embedded, and the permanent magnets are fixed with adhesive on at least a portion of the inner circumferential side and the outer circumferential side inside the magnet accommodating holes, and at least a portion of the permanent magnets has a gap portion where they are not fixed with adhesive, so that the gap portion can suppress outer diameter runout of the rotor core on the outer diameter side of the permanent magnets.

[0063] Fourth Embodiment A rotating electric machine according to a fourth embodiment will now be described with reference to the drawings. Fig. 13 is an axial cross-sectional view of a rotor 300 of a rotating electric machine according to the fourth embodiment. The fourth embodiment differs from the first to third embodiments in the arrangement of the magnet accommodating holes 311a and the permanent magnets 321 in the rotor core 311.

[0064] In FIG. 13 , the magnet accommodating holes 311a and the permanent magnets 321 are arranged alternately at different angles around the rotor core 311, forming a V-shaped magnet arrangement. The bridge portions 331b sandwiched between the flux barrier portions 331a of adjacent permanent magnets 321 forming the V-shape are located on both the outer and inner sides. In a V-shaped magnet arrangement, the radial thickness of the rotor core is particularly thin at the outer bridge portion 331b closest to the outer diameter, making it easy for distortion on the inner side to propagate to the outer periphery. Therefore, as shown in FIG. 13 , it is desirable to position the openings 311d on the inner side between the outer bridge portion 331b and the shaft (boss portion 410). In other words, no openings are positioned between the inner bridge portion 331b and the shaft, as in the area indicated by the dashed line C in FIG. 13 . This configuration prevents the influence of the pressure of the boss portion 410 when the shaft is press-fitted into the rotor core 311 from being transmitted to the outer periphery of the rotor core 311.

[0065] While Figure 13 illustrates an example of a rectangular opening 311d, it goes without saying that the above-described first embodiment and various modified examples can also be applied. That is, the opening can be an oval shape, a U-shape surrounding the crimped portion, or the like. It is also possible to use an opening formed by cutting out a recess on the inner periphery of the rotor core 311, or by forming a groove (recess) on the shaft side. A combination of these can also be applied, and the same effect as in the first embodiment can be achieved.

[0066] As described above, embodiment 4 can also be applied to a rotor with a V-shaped magnet arrangement in which the permanent magnets are embedded in a V-shaped arrangement with alternating angles around the circumferential direction of the rotor core, and the bridge portion between the flux barrier portions of adjacent permanent magnets has an outer periphery bridge portion located on the outer periphery side of the rotor core and an outer periphery bridge portion located on the inner periphery side, and an opening is provided between the outer periphery bridge portion and the shaft, so that the same effects as embodiment 1 can be achieved even in a rotating electric machine equipped with a rotor with a V-shaped magnet arrangement.

[0067] Although various exemplary embodiments and examples are described in this disclosure, 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 variations not illustrated are anticipated within the scope of the technology disclosed in this specification. 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.

[0068] 100: Rotating electric machine, 210: Housing, 211: Frame, 212: End plate, 220: Stator, 300: Rotor, 311: Rotor core, 311a: Magnet accommodating hole, 311d, 311g, 410g: Opening, 311e: Crimped portion, 311f: Gap portion, 321: Permanent magnet, 321a: Adhesive, 331a: Flux barrier portion, 331b: Bridge portion, 361: Rotating shaft radial V-crimped portion, 400: Rotation holder, 410: Boss portion, 500: Bearing.

Claims

1. A rotating electric machine having a rotor comprising a rotor core and a plurality of permanent magnets embedded circumferentially on the outer periphery of the rotor core, with a shaft pressed into the inner periphery, wherein the rotor is provided with flux barrier portions at both circumferential ends of the permanent magnets, and an opening is provided between the shaft and a bridge portion between the flux barrier portions of adjacent permanent magnets.

2. The rotating electric machine according to claim 1, wherein the opening penetrates in the axial direction.

3. A rotating electric machine according to claim 1 or 2, wherein the opening is provided in the rotor core and has a shape that is flattened in a direction perpendicular to the radial direction.

4. A rotating electric machine according to any one of claims 1 to 3, wherein the openings are provided in the rotor core, and two openings are provided in the radial direction with the crimped portion sandwiched between them.

5. A rotating electric machine according to claim 1 or 2, wherein the opening is provided in the rotor core, has a U-shape, and two openings are provided in the radial direction with a crimped portion sandwiched between them.

6. A rotating electric machine according to claim 1 or 2, wherein the opening is an opening provided between the shaft and a recess formed in the inner peripheral portion of the rotor core.

7. A rotating electric machine according to claim 1 or 2, wherein the opening is an opening provided between a groove formed in the outer periphery of the shaft in the axial direction and the rotor core.

8. A rotating electric machine according to any one of claims 1 to 7, further comprising the opening between the permanent magnet and the shaft.

9. A rotating electric machine according to claim 8, wherein the rotor core has magnet accommodating holes in which the permanent magnets are embedded, and the permanent magnets are fixed inside the magnet accommodating holes by being filled with adhesive around the entire circumference.

10. A rotating electric motor as described in any one of claims 1 to 8, wherein the rotor core has magnet accommodating holes in which the permanent magnets are embedded, and the permanent magnets are fixed with adhesive on at least a portion of the inner and outer circumferential sides inside the magnet accommodating holes, and have at least a gap portion that is not fixed with adhesive.

11. A rotating electric machine as described in any one of claims 1 to 7, wherein the permanent magnets are embedded in a V-shaped arrangement with alternating angles in the circumferential direction of the rotor core, the bridge portions between the flux barrier portions of adjacent permanent magnets have an outer bridge portion located on the outer periphery of the rotor core and an outer bridge portion located on the inner periphery, and the opening is provided between the outer bridge portion and the shaft.

12. A method for manufacturing a rotating electric machine according to any one of claims 1 to 11, comprising the steps of press-fitting the shaft into a rotor core having the opening, hardening an adhesive to fix the permanent magnet to the rotor core, and magnetizing the fixed permanent magnet.

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