Rotor for rotary electric machine

Abstract

The present invention discloses a rotor for a rotary electric machine, comprising: a rotor core having an annular shape when viewed in an axial direction; a rotor shaft disposed on the inside in the radial direction of the rotor core and coupled to the rotor core by means of interference in the radial direction; and a magnet disposed in the rotor core for each magnetic pole so that a plurality of magnetic poles are formed in the circumferential direction. The rotor core has a plurality of holes extending in the axial direction at a position closer to the radial inner side than the magnet, and the plurality of holes respectively form a first hole row and a second hole row arranged in the circumferential direction at a first radial position and a second radial position in a sequence closer to the radial position of the magnet. A first circumferential range between adjacent plural holes forming the first hole row is offset in a circumferential direction with respect to a circumferential position between the magnets of each magnetic pole.

Description

Technical Field

[0001] The present disclosure relates to a rotor for a rotating electrical machine. Background Art

[0002] A technique is known in which magnet holes for inserting a plurality of permanent magnets are formed in a rotor core of a rotating electrical machine rotor, and slits are formed radially inward of the magnet holes.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-136785 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, the above-mentioned conventional technology still has difficulty in coping with the increase in centrifugal force associated with the higher rotation speed of the rotating electrical machine. In other words, the change (increase) in the inner diameter of the rotor core caused by the centrifugal force still tends to increase.

[0008] Therefore, in one aspect, an object of the present disclosure is to achieve a further reduction in the amount of change in the inner diameter of the rotor core caused by centrifugal force.

[0009] Technical means to solve the problem

[0010] In one aspect, a rotor for a rotating electrical machine is provided, wherein:

[0011] include:

[0012] A rotor core that is annular when viewed along the axial direction;

[0013] a rotor shaft, disposed radially inward of the rotor core and coupled to the rotor core with radial interference; and

[0014] a magnet disposed on the rotor core so as to form a plurality of magnetic poles along the circumferential direction;

[0015] The rotor core has a plurality of holes extending in the axial direction at a position radially inward of the magnets.

[0016] The plurality of holes form a first hole row in which the plurality of holes are circumferentially arranged at a first radial position radially inward of the radial position of the magnet, and a second hole row in which the plurality of holes are circumferentially arranged at a second radial position radially inward of the first radial position.

[0017] The first circumferential range between the plurality of adjacent holes forming the first hole row is circumferentially offset relative to the circumferential position of the q-axis.

[0018] Effects of the Invention

[0019] In one aspect, according to the present disclosure, it is possible to further reduce the amount of change in the inner diameter of the rotor core caused by centrifugal force. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a cross-sectional view schematically showing the cross-sectional structure of a motor according to an embodiment.

[0021] Figure 2 It is a cross-sectional view of the rotor core of the rotor (a cross-sectional view taken along a plane perpendicular to the axial direction).

[0022] Figure 3 It is an enlarged view of a portion of one magnetic pole of the rotor and a portion of its adjacent portion.

[0023] Figure 4 It is an enlarged view of a portion of one magnetic pole and a portion of an adjacent portion of a rotor core of a comparative example.

[0024] Figure 5 This is a diagram showing the analysis results of the amount of change in the inner diameter of the rotor core when centrifugal force is generated.

[0025] Figure 6 This is an enlarged view of a portion of one magnetic pole and a portion of an adjacent portion of a rotor core according to a modified example. DETAILED DESCRIPTION

[0026] The following describes various embodiments in detail with reference to the accompanying drawings. The dimensional ratios in the drawings are merely examples and are not intended to be limiting. For ease of explanation, shapes and other aspects of the drawings may be partially exaggerated. In the drawings, for ease of viewing, reference numerals may be assigned to only some of the components with the same attributes.

[0027] Figure 1 It is a cross-sectional view schematically showing the cross-sectional structure of the motor 1 according to one embodiment. Figure 2 It is a cross-sectional view of the rotor core 32 of the rotor 30 (a cross-sectional view taken along a plane perpendicular to the axial direction). Figure 3 It is an enlarged view of a portion of one magnetic pole of the rotor 30 and a portion of an adjacent portion thereof.

[0028] exist Figure 1 , the rotating shaft 12 of the motor 1 is shown. In the following description, the axial direction refers to the direction in which the rotating shaft (rotation center) 12 of the motor 1 extends, and the radial direction refers to the radial direction centered on the rotating shaft 12. Therefore, the radially outer side refers to the side away from the rotating shaft 12, and the radially inner side refers to the side toward the rotating shaft 12. Furthermore, the circumferential direction corresponds to the direction of rotation around the rotating shaft 12.

[0029] The motor 1 may be a vehicle driving motor used in, for example, a hybrid vehicle or an electric vehicle, but the motor 1 may also be used for any other purpose.

[0030] The motor 1 is an inner rotor type, and the stator 21 is provided around the radially outer side of the rotor 30. The stator 21 is fixed to the motor housing 10. The stator 21 has a stator core 211 composed of, for example, an annular magnetic laminated steel plate. A plurality of slots (not shown) are formed radially inside the stator core 211, around which the coils 22 are wound.

[0031] The rotor 30 is arranged radially inside the stator 21 .

[0032] The rotor 30 includes a rotor core 32, a rotor shaft 34, end plates 35A and 35B, and magnet pieces 61 and 62. The end plates 35A and 35B may be omitted.

[0033] The rotor core 32 is fixed to the radially outer surface of the rotor shaft 34 and rotates integrally with the rotor shaft 34. The rotor core 32 has an axial hole 320 (see Figure 2 ), and the rotor shaft 34 is fitted into the shaft hole 320. The rotor core 32 is coupled to the rotor shaft 34 with a radial interference fit. That is, the rotor core 32 and the rotor shaft 34 are coupled to each other by fixing using an interference fit. For example, the rotor core 32 and the rotor shaft 34 can be coupled with a radial interference fit by shrink fit, press fit, hydroforming, or similar methods. However, the coupling force between the rotor core 32 and the rotor shaft 34 includes not only the radial interference fit but also the axial force generated by the nut, etc.

[0034] The rotor shaft 34 is rotatably supported by the motor housing 10 via bearings 14a and 14b. The rotor shaft 34 defines the rotating shaft 12 of the motor 1.

[0035] The rotor core 32 is formed of, for example, an annular magnetic laminated steel plate. Magnet pieces 61 and 62 are embedded in the rotor core 32 (see FIG. Figure 3 That is, the rotor core 32 has magnet holes 321 and 322 that penetrate in the axial direction (see Figure 2 ), magnet pieces 61, 62 are inserted and fixed in the magnet holes 321, 322. In a modified example, the rotor core 32 may be formed of a powder compact formed by compressing and solidifying magnetic powder.

[0036] The rotor core 32 is designed to have a circular shape with an outer diameter r1 and an inner diameter r2 (the diameter of the shaft hole 320). In a modified example, the circular shape of the rotor core 32 does not need to be a perfect circle, and may be a circular shape with a notch in part, for example.

[0037] like Figure 2As shown, the rotor core 32 has a rotationally symmetrical shape with the rotation axis 12 as the center when viewed in the axial direction. Figure 2 In the illustrated example, the rotor core 32 is configured such that each set of magnet pieces 61 and 62 overlaps each other every time the rotor core 32 rotates 45 degrees around the rotation shaft 12 .

[0038] The plurality of magnet pieces 61 and 62 are in the form of sintered magnets and can be formed of neodymium or the like. However, in a modified embodiment, magnets formed of bonded magnet material can also be used instead of the magnet pieces 61 and 62. In this embodiment, as an example, Figure 3 As shown, the plurality of magnet pieces 61 and 62 are arranged in a manner that is rotationally symmetrical with respect to each magnetic pole when viewed in the axial direction. In addition, the plurality of magnet pieces 61 and 62 are arranged in a manner that the S pole and the N pole appear alternately in the circumferential direction. In this embodiment, the number of magnetic poles is eight, but the number of magnetic poles is arbitrary. In addition, in this embodiment, the magnet pieces 61 and 62 are the same straight-line shape when viewed in the axial direction, but can also be different shapes. In addition, at least one of the magnet pieces 61 and 62 can also be in an arc-shaped shape when viewed in the axial direction.

[0039] In addition, Figure 1 , a motor 1 having a specific structure is shown, but the structure of the motor 1 is not limited to this specific structure. Figure 1 In the embodiment, the rotor shaft 34 is hollow, but it can also be solid.

[0040] Next, refer to Figure 3 The following figures will explain the rotor core 32 and the magnet pieces 61 and 62 in more detail. Although the structure of one magnetic pole will be explained below, the structures of the other magnetic poles may be the same.

[0041] like Figure 3 As shown, the structure of one magnetic pole is basically relative to the d-axis (in the direction of the main magnetic flux (the direction of the field pole) Figure 3 The d-axis is symmetrical. The direction of the d-axis corresponds to the direction of the magnetic field generated by the magnet pieces 61 and 62 arranged on the rotor 30. In the following, the circumferential outer side refers to the side away from the d-axis, and the circumferential inner side refers to the side close to the d-axis. The d-axis is formed at the circumferential center of the circumferential range of each magnetic pole, and the q-axis (at Figure 3 The q-axis (expressed in English as "q-axis") is formed at the boundary of the circumferential extent of each magnetic pole (the circumferential position between the magnet pieces 61, 62 of each magnetic pole).

[0042] The rotor core 32 includes magnet holes 321 (hereinafter referred to as "first-layer magnet holes 321") and magnet holes 322 (hereinafter referred to as "second-layer magnet holes 322"). The magnet holes 321 and 322 are formed to be rotationally symmetrical for each magnetic pole.

[0043] The magnet holes 321 of the first layer are formed in pairs in a roughly V-shape (a roughly V-shape that opens radially outward or radially inward). However, in a modified example, the magnet holes 321 of the first layer can also be formed in pairs in a straight line, or can be achieved by a single straight line (a straight line perpendicular to the d-axis). A magnet piece 61 is provided in each of the magnet holes 321 of the first layer. In addition, a gap is provided between the magnet holes 321 of the first layer and the magnet piece 61 at both ends in the longitudinal direction of the magnet piece 61. In addition, the gap can be a cavity or can be filled with resin, etc.

[0044] The second-layer magnet holes 322 are positioned radially inward relative to the first-layer magnet holes 321. Regarding the positional relationship between the first-layer magnet holes 321 and the second-layer magnet holes 322, "radially outward" or "radially inward" refers to the positional relationship when compared at the point where a common line segment passing through the rotation axis 12 intersects, as viewed axially. This also applies to the positional relationship between the first portion 3211 and the first-layer magnet holes 321, described later.

[0045] Like the first-layer magnet holes 321, the second-layer magnet holes 322 are formed in pairs symmetrically about the d-axis. Furthermore, the second-layer magnet holes 322 on either side of the d-axis extend circumferentially wider than the first-layer magnet holes 321 on either side of the d-axis. A magnet piece 62 is positioned above each of the second-layer magnet holes 322. Furthermore, gaps are provided between the second-layer magnet holes 322 and the magnet piece 62 at both ends of the magnet piece 62 in the longitudinal direction. These gaps can be hollow or filled with resin, for example.

[0046] In this embodiment, two second-layer magnet holes 322 are formed on one side of the d-axis in the circumferential direction, and two are formed on the other side of the d-axis in the circumferential direction. That is, a total of four second-layer magnet holes 322 are formed for one magnetic pole.

[0047] The rotor core 32 has the first and second magnet holes 321 and 322 , and thus has three portions 3211 , 3212 , and 3213 (hereinafter also referred to as a first portion 3211 , a second portion 3212 , and a third portion 3213 ) connected in the radial direction only via bridge portions.

[0048] Specifically, the first portion 3211 extends radially outward relative to the first layer of magnet holes 321. The first portion 3211 forms a portion 328A of the outer peripheral surface 328 of the rotor core 32 (see Figure 3 The first portion 3211 forms a magnetic path for the q-axis magnetic flux. Specifically, the q-axis magnetic flux of the first portion 3211 flows from one circumferential end of the first portion 3211 toward the other circumferential end through the first portion 3211 (a region radially outward of the first layer's magnet holes 321).

[0049] The second portion 3212 passes between the second layer magnet holes 322 and the first layer magnet holes 321 and extends to the outer peripheral surface 328 of the rotor core 32 on both sides of the circumference. The second portion 3212 forms a portion 328B of the outer peripheral surface 328 of the rotor core 32 (hereinafter also referred to as "the outer peripheral surface portion 328B of the second portion 3212") on both sides of the circumference of the first portion 3211 (see Figure 3 The second portion 3212 forms a magnetic path for the q-axis magnetic flux. Specifically, the q-axis magnetic flux of the second portion 3212 flows from one end of the second portion 3212 (one outer peripheral surface 328B) toward the other end (the other outer peripheral surface 328B) through the second-layer magnet holes 322 and the first-layer magnet holes 321.

[0050] The third portion 3213 passes through the radially inner side of the second layer of magnet holes 322 and extends to the outer peripheral surface 328 of the rotor core 32 on both circumferential sides. The third portion 3213 forms a portion 328C of the outer peripheral surface 328 of the rotor core 32 on both circumferential sides of the second portion 3212 (see FIG. Figure 3 ).

[0051] In addition, in this embodiment, the mass of the third portion 3213 may be significantly greater than the mass of the second portion 3212 , and the mass of the second portion 3212 may be significantly greater than the mass of the first portion 3211 .

[0052] Furthermore, the rotor core 32 includes the three portions 3211 , 3212 , and 3213 , thereby including a plurality of bridge portions 41 , 42 , 43 , 44 , and 45 connecting the three portions 3211 , 3212 , and 3213 .

[0053] The bridge portion 41 (hereinafter referred to as the "first bridge portion 41") supports the first portion 3211 radially outwardly from the second portion 3212. Specifically, the first bridge portion 41 connects the second portion 3212 to the first portion 3211 and extends circumferentially. The first bridge portions 41 are provided in pairs on both circumferential sides (circumferentially outward) of the first portion 3211.

[0054] The bridge portion 42 (hereinafter referred to as the "second bridge portion 42") supports the second portion 3212 radially outwardly from the third portion 3213. Specifically, the second bridge portion 42 connects the third portion 3213 to the second portion 3212 and extends circumferentially. The second bridge portions 42 are provided in pairs on both circumferential sides (circumferentially outward) of the second portion 3212.

[0055] The bridge portion 43 (hereinafter referred to as “first center bridge portion 43 ”) supports the first site 3211 on the second site 3212 along the d-axis.

[0056] The bridge portion 44 (hereinafter referred to as “second center bridge portion 44 ”) supports the second site 3212 on the third site 3213 along the d-axis.

[0057] The bridge portion 45 (hereinafter referred to as “second intermediate bridge portion 45 ”) supports the second portion 3212 on the third portion 3213 between the two second-layer magnet holes 322 .

[0058] exist Figure 3 In the illustrated example, the magnet pieces 61 inserted into the first-layer magnet holes 321 form the first layer of permanent magnets from the radially outer side, and the magnet pieces 62 inserted into the second-layer magnet holes 322 form the second layer of permanent magnets from the radially outer side. Furthermore, in this embodiment, a single magnet piece (either magnet piece 61 or magnet piece 62) is inserted into each magnet hole (the first-layer magnet hole 321 or the second-layer magnet hole 322). However, in a modified example, two or more magnet pieces may be inserted into a single magnet hole.

[0059] In addition, Figure 3 In the illustrated example, neither the first-layer magnet holes 321 nor the second-layer magnet holes 322 extend along the d-axis, but rather have first and second center bridge portions 43 and 44 along the d-axis. However, in a modified embodiment, either or both of the first-layer magnet holes 321 and the second-layer magnet holes 322 may extend along the d-axis.

[0060] In addition, Figure 3 In the example shown, the magnet pieces 61 and 62 do not extend on the d-axis, similarly to the magnet holes 321 of the first layer and the magnet holes 322 of the second layer. However, only one or both of them may extend on the d-axis. In addition, at least one of the first bridge portion 41, the second bridge portion 42, and the second intermediate bridge portion 45 may be omitted. Figure 3 In the example shown, the magnet pieces 61 and 62 are arranged in two layers in the radial direction. However, a single-layer structure (for example, a structure in which one of the magnet pieces 61 and 62 is omitted) or a structure with three or more layers may be used.

[0061] Next, refer to Figure 3The characteristic structure of this embodiment will be described.

[0062] In this embodiment, if Figure 3 As shown, the rotor core 32 has a first slit 71 and a second slit 72 radially inward of the magnet holes 321, 322 (and the magnet pieces 61, 62 therein). Specifically, the first slit 71 and the second slit 72 are formed in the third portion 3213 of the rotor core 32. The first slit 71 and the second slit 72 are each in the form of an axial hole extending axially through the rotor core 32.

[0063] The first slit 71 is located radially inward of the magnet hole 322 and radially outward of the second slit 72 (hereinafter referred to as the "first radial position"). The second slit 72 is located radially inward of the first slit 71 and radially outward of the shaft hole 320 (hereinafter referred to as the "second radial position").

[0064] A plurality of first slits 71 are provided. The plurality of first slits 71 are arranged at first radial positions so as to be rotationally symmetrical with respect to each magnetic pole. The plurality of first slits 71 form a circumferentially arranged hole row (an example of a first hole row). In this embodiment, the first slit 71 for each magnetic pole consists of one slit with its circumferential center on the d-axis and two halves of each slit with its circumferential center on the q-axis (the halves divided by the q-axis).

[0065] A bridge portion (hereinafter also referred to as "first inter-slit bridge 710") extending in the radial direction is formed in the circumferential range (an example of the first circumferential range) between the plurality of first slits 71. Figure 3 As shown in FIG, the first inter-slit bridge 710 is offset in the circumferential direction relative to the q-axis. That is, the first inter-slit bridge 710 is formed at a position where the q-axis does not pass. Figure 3 As shown, the first inter-slit bridge 710 is offset in the circumferential direction with respect to the d-axis. That is, the first inter-slit bridge 710 is formed at a position where neither the d-axis nor the q-axis passes through.

[0066] A plurality of second slits 72 are provided. The plurality of second slits 72 are arranged at second radial positions so as to be rotationally symmetrical with respect to each magnetic pole. The plurality of second slits 72 form a circumferentially arranged hole row (an example of a second hole row). In this embodiment, the second slits 72 for each magnetic pole are composed of two slits between the d-axis and the q-axis in the circumferential direction.

[0067] A bridge portion (hereinafter also referred to as "second inter-slit bridge 720") extending in the radial direction is formed in the circumferential range (an example of the second circumferential range) between the plurality of second slits 72. Figure 3As shown, a portion of the plurality of second inter-slit bridges 720 is formed on the q-axis, and the rest is formed on the d-axis. That is, the plurality of second inter-slit bridges 720 are composed of the second inter-slit bridges 720 on the q-axis and the second inter-slit bridges 720 on the d-axis.

[0068] Here, refer to Figure 4 The comparative examples shown and Figure 5 The analysis results shown are used to illustrate the effects of this embodiment.

[0069] Figure 4 This is an enlarged view of a portion of one magnetic pole of the rotor core 32' of the comparative example and a portion of its adjacent portion. Figure 3 Comparison chart.

[0070] The difference of the rotor core 32' of the comparative example is that the first slit 71 and the second slit 72 are replaced by the first slit 71' and the second slit 72'. The first slit 71' and the second slit 72' have different circumferential phases compared to the first slit 71 and the second slit 72 of the present embodiment. That is, the first slit 71' of each magnetic pole is composed of two slits between the d-axis and the q-axis in the circumferential direction. In this case, the first inter-slit bridge 710' extends on the q-axis or the d-axis. In addition, the second slit 72' of each magnetic pole is composed of one slit whose circumferential center is located on the d-axis and one half of each of the two slits whose circumferential centers are located on the q-axis (the halves divided by the q-axis). In this case, the second inter-slit bridge 720' is offset in the circumferential direction relative to the d-axis and the q-axis.

[0071] Figure 5 The inner diameter of the rotor core 32 when the motor 1 (rotor 30) is rotated at high speed to generate centrifugal force (see Figure 2 Graph showing the analytical results of the maximum value of the change in r2).

[0072] exist Figure 5 Zhongyu Figure 4 The comparative example shown in FIG. 1 shows the analysis results of the present embodiment and another comparative example together. The vertical axis of the bar graph represents the inner diameter of the rotor core 32 (see FIG. 1 ). Figure 2 The maximum value of the change in r2) (hereinafter also referred to as "core inner diameter change") decreases as it goes down. In addition, the inner diameter of the rotor core 32 (refer to Figure 2 The maximum value of the change amount r2) refers to the maximum value among the various changes at different circumferential positions of the peripheral edge portion of the shaft hole 320 of the rotor core 32.

[0073] Although not shown in the figure, another comparative example is a structure without slits such as the first slit 71 and the second slit 72, the first slit 71' and the second slit 72', and is hereinafter also referred to as a "comparative example without slits". Figure 5 In order to distinguish, Figure 4 The comparative example shown is also referred to as a "comparative example with slits".

[0074] If the change (increase) in the core inner diameter is too large, the radial interference between the rotor core 32 and the rotor shaft 34 may be significantly reduced or eliminated, potentially hindering torque transmission between the rotor core 32 and the rotor shaft 34. The greater the centrifugal force (i.e., the higher the rotation speed), the greater the change (increase) in the core inner diameter. Therefore, a smaller change in the core inner diameter is more advantageous in achieving higher rotation speeds in the motor 1.

[0075] from Figure 5 It can be seen that in this embodiment, Figure 4 Similarly, the comparative example with slits shown in the figure shows a significantly reduced change in the core inner diameter compared to the comparative example without slits. This demonstrates that the first slits 71 and the second slits 72 (and similarly the first slits 71' and the second slits 72') function to mitigate the radially outward force exerted on the peripheral edge of the axial hole 320 of the rotor core 32 by centrifugal force. According to this embodiment, the two-layer (two-row) structure, in which the first slits 71 and the second slits 72 are arranged at different radial positions, effectively enhances this mitigating function.

[0076] In addition, in this embodiment, Figure 4 Similarly to the comparative example with slits shown, the circumferential positions (phases) of the first inter-slit bridge 710 and the second inter-slit bridge 720 are different from each other. This effectively mitigates the radially outward force exerted on the peripheral edge of the axial hole 320 of the rotor core 32 by centrifugal force. Consequently, the change in the core inner diameter can be effectively reduced.

[0077] In addition, in this embodiment, Figure 5 As shown, Figure 4 Compared with the comparative example shown in FIG. 1 , the change in the core inner diameter can be further reduced. This is because, in this embodiment, the first inter-slit bridge 710 is offset in the circumferential direction relative to the q-axis as described above. When the first inter-slit bridge 710 is offset in the circumferential direction relative to the q-axis, the force exerted on the entire peripheral portion of the axial hole 320 of the rotor core 32 is alleviated. This is because Figure 3 The radially outward force F1 along the q-axis is actually supported by the three second inter-slit bridges 720 (refer to force F3) via the two first inter-slit bridges 710 (refer to force F2). Figure 4 In the comparative example shown, the radially outward force F1 ′ along the q-axis is substantially borne by the two second inter-slit bridges 720 ′ (see force F2 ′).

[0078] Here, the radially outward force F1 along the q-axis is described, but the radially outward force along the d-axis has the same tendency. In addition, the radially outward force F1 along the q-axis generated by the centrifugal force tends to be greater than the radially outward force along the d-axis.

[0079] Thus, according to this embodiment, Figure 4 Compared with the comparative example shown, the amount of change in the inner diameter of the rotor core 32 caused by the centrifugal force can be further reduced. As a result, the motor 1 can be rotated at a higher speed.

[0080] Next, refer to Figure 6 Modifications will be described.

[0081] Figure 6 This is an enlarged view of a portion of one magnetic pole of the rotor core 32A of the modified example and a portion of its adjacent portion, which is different from the previous Figure 3 The corresponding figure.

[0082] The rotor core 32A of this modification differs in that the first slits 71 and the second slits 72 are replaced with first slits 71A and second slits 72A. The first slits 71A and second slits 72A have the same circumferential phase as the first slits 71 and second slits 72 of this embodiment, but have a different radial relationship and shape.

[0083] Specifically, in this modification, if Figure 6 As shown, the radial extension ranges of the first slit 71A and the second slit 72A overlap each other. That is, the radially inner portion of the first slit 71A and the radially outer portion of the second slit 72A are offset in the circumferential direction and extend in the same radial range.

[0084] In this case, the first slit 71A has a slit configuration in which the circumferential slit width gradually narrows as it moves radially inward, and the second slit 72A has a slit configuration in which the circumferential slit width gradually narrows as it moves radially outward. Furthermore, a portion 730A connecting the first inter-slit bridge 710A and the second inter-slit bridge 720A extends in both the circumferential and radial directions.

[0085] According to this modification, the same effect as the above embodiment can be obtained. Furthermore, according to this modification, the radial extension range of the first slit 71A and the radial extension range of the second slit 72A overlap, so that the radial extension range of the first slit 71 and the second slit 72 as a whole can be minimized. As a result, the distance L6 between the radial extension range of the slit and the radial extension range of the magnet in the rotor core 32A can be reduced (see Figure 6 ) becomes relatively large. As a result, the strength of the rotor core 32A can be improved, and the stress generated in each bridge portion (bridge portions 41, 42, etc.) can be effectively reduced.

[0086] Although each embodiment has been described in detail above, the present invention is not limited to the specific embodiment and various modifications and changes can be made within the scope of the claims. In addition, all or a plurality of the structural components of the above-mentioned embodiments can be combined.

[0087] For example, in the above-described embodiment (and the same applies to the modified embodiment), the slit structure comprises two rows of holes, one comprising a plurality of first slits 71 and one comprising a plurality of second slits 72. However, the number of rows is arbitrary, and a slit structure of three or more rows is also possible. In this case, the plurality of slits forming the hole row closest to the radial outside (i.e., the hole row closest to the radial extension range of the magnet) can have the same structure (circumferential phase) as the plurality of first slits 71. In this case, the plurality of slits forming the second radially outer hole row have the same structure (circumferential phase) as the plurality of second slits 72, and the plurality of slits forming the third radially outer hole row have the same structure (circumferential phase) as the plurality of first slits 71, and the same applies to the following.

[0088] Description of reference numerals:

[0089] 30: Rotor (rotor for rotating electrical machine), 32: Rotor core, 34: Rotor shaft, 61, 62: Magnet pieces (magnets), 71: First slit (axial hole forming the first hole row), 72: Second slit (axial hole forming the second hole row).

Claims

1. A rotor for a rotating electrical machine, in, include: A rotor core that is annular when viewed along the axial direction; a rotor shaft, disposed radially inward of the rotor core and coupled to the rotor core with radial interference; and a magnet disposed on the rotor core so as to form a plurality of magnetic poles along the circumferential direction; The rotor core has a plurality of holes extending in the axial direction at a position radially inward of the magnets. The plurality of holes form a first hole row in which the plurality of holes are circumferentially arranged at a first radial position radially inward of the radial position of the magnet, and a second hole row in which the plurality of holes are circumferentially arranged at a second radial position radially inward of the first radial position. A first circumferential range between adjacent holes forming the first hole row is circumferentially offset relative to the circumferential position of the q-axis.

2. The rotor for a rotating electrical machine according to claim 1, wherein: The first circumferential extent is also circumferentially offset relative to the circumferential position of the d-axis.

3. The rotor for a rotating electrical machine according to claim 2, wherein: A second circumferential range between the axial holes forming the second hole row includes a circumferential position of the q-axis.

4. The rotor for a rotating electrical machine according to claim 3, wherein: The second circumferential range includes the circumferential position of the d-axis.

5. The rotor for a rotating electrical machine according to any one of claims 1 to 4, wherein: The radial extensions of the first hole row and the second hole row overlap with each other.

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