Rotary electric machine

Abstract

To provide a rotary electric machine capable of improving endurance of a rotor core for centrifugal force at a time of high-speed rotation.SOLUTION: A rotor of a rotary electric machine has: a rotor core which has a plurality of magnetic poles arranged along an outer peripheral surface facing an inner peripheral surface of a stator core at a gap; and a plurality of permanent magnets which are provided at each of the magnetic poles. The rotor is provided rotatably around a center axis concentric with the stator core. The rotor core is configured by laminating a plurality of thin core pieces concentrically with the center axis, and has two embedment holes which are provided on both sides of a d-axis in each of the magnet poles and in which the permanent magnets are loaded, respectively. Each of the plurality of core pieces has a thin part which is thinner than other parts in the whole thereof and is deformable with respect to the other parts.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotating electric machine. [Background technology]

[0002] In recent years, due to remarkable research and development of permanent magnets, permanent magnets with high magnetic energy products have been developed. Permanent magnet type rotating electric machines using such permanent magnets are used as electric motors or generators for trains and automobiles. Normally, a permanent magnet type rotating electric machine has a cylindrical stator and a columnar rotor supported inside the stator so as to be freely rotatable. The rotor has a rotor core and a number of permanent magnets embedded in the rotor core.

[0003] In such permanent magnet type rotating electric machines, it has been proposed to form a magnetic circuit that can utilize reluctance torque in addition to magnet torque by arranging a pair of permanent magnets symmetrically at each magnetic pole so that they open from the inner circumferential surface side toward the outer circumferential surface side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-185081 A [Patent Document 2] International Publication No. 2018 / 012599 Brochure [Patent Document 3] JP 2014-050208 A Summary of the Invention [Problem to be solved by the invention]

[0005] 2. Description of the Related Art When a rotating electric machine is used as an electric motor for a vehicle such as a train or an automobile, it is necessary to take into consideration the effect of centrifugal force when the rotating electric machine rotates at high speed. The present invention has been made in light of the above, and an object of the present invention is to provide a rotating electric machine capable of improving the durability of a rotor core against centrifugal force during high speed rotation. [Means for solving the problem]

[0006] A rotating electric machine according to an embodiment includes a stator and a rotor. The stator includes a cylindrical stator core in which teeth and slots are alternately arranged in the circumferential direction, and an armature winding wound around the teeth through the slots. The rotor includes a rotor core having a plurality of magnetic poles arranged along an outer circumferential surface facing the inner circumferential surface of the stator core with a gap therebetween, and a plurality of permanent magnets provided on each of the magnetic poles, and is provided rotatably about a central axis that is concentric with the stator core. In a cross section of the rotor core perpendicular to the central axis, an axis extending radially through the circumferential ends of the magnetic poles and the central axis is defined as a q-axis, and an axis electrically spaced 90 degrees from the q-axis in the circumferential direction is defined as a d-axis. The rotor core is configured by stacking a plurality of thin-plate-shaped core pieces concentrically with the central axis, and has two embedding holes provided on both sides of the d-axis in each of the magnetic poles, into which the permanent magnets are respectively loaded. Each of the plurality of core pieces has a thin portion that is thinner than other portions throughout the entirety and is deformable relative to the other portions. [Brief description of the drawings]

[0007] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a rotating electric machine according to a first embodiment. [Diagram 2] 2 is an enlarged view of a part (one magnetic pole portion) of the rotor of the rotating electric machine according to the first embodiment shown in FIG. 1; [Diagram 3] 1 is a perspective view that illustrates a schematic view of the vicinity of an embedding hole in a rotor core of a rotor in a rotating electric machine according to a first embodiment. [Figure 4] 3 is a perspective view showing an example of a configuration of a thin-walled portion in a rotor core segment of a rotor core of a rotating electric machine according to a first embodiment. FIG. [Diagram 5]FIG. 4 is a perspective view illustrating a first modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 6] FIG. 4 is a perspective view illustrating a second modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 7] FIG. 11 is a perspective view illustrating a third modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 8] FIG. 11 is a perspective view illustrating a fourth modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 9] FIG. 11 is a perspective view illustrating a fifth modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 10] FIG. 13 is a perspective view illustrating a sixth modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 11] FIG. 13 is a perspective view illustrating a seventh modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 12] FIG. 13 is a perspective view illustrating an eighth modified example of a thin-walled portion in a rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 13] FIG. 13 is a perspective view illustrating a ninth modified example of the thin-walled portion in the rotor core segment of the rotor core of the rotating electric machine according to the first embodiment. [Figure 14] 3 is a schematic diagram showing a state (initial state) in which permanent magnets are loaded into loading areas of embedding holes in a rotor core in the rotating electric machine according to the first embodiment; FIG. [Figure 15] 4 is a schematic diagram illustrating a contact state between a permanent magnet and a thin portion of a rotor core piece when a centrifugal force acts on the rotor of the rotating electric machine according to the first embodiment as the rotor rotates at high speed; FIG. [Figure 16] 13 is a diagram illustrating a cross section, taken along a predetermined plane, of a thin-walled portion of a rotor core segment of a rotor core of a rotating electric machine according to a second embodiment. FIG. [Figure 17]13 is a diagram illustrating a cross section, taken along a predetermined plane, of a thin-walled portion of a rotor core segment of a rotor core for a rotating electric machine according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a rotating electric machine according to an embodiment will be described with reference to the drawings. Note that the same reference numerals are used to designate common components throughout the embodiments, and duplicated descriptions will be omitted. Also, each figure is a schematic diagram for facilitating understanding of the embodiment and its configuration, dimensions, ratios, etc., and although there are some differences from the actual device, these can be appropriately modified in design by taking into consideration the following description and known techniques.

[0009] (First embodiment) 1 is a cross-sectional view showing a schematic configuration of a permanent magnet type rotating electric machine according to this embodiment, specifically, a cross-sectional view taken along a plane perpendicular to the central axis of the rotating electric machine. The rotating electric machine is used as a main motor, a drive motor, or a generator in, for example, a railroad car, a hybrid electric vehicle (HEV), or an electric vehicle (EV). However, the use of the rotating electric machine is not limited to this, and it can also be used for other purposes.

[0010] As shown in Fig. 1, the rotating electric machine 10 is configured as, for example, an inner rotor type rotating electric machine. The rotating electric machine 10 includes an annular or cylindrical stator 12 supported by a fixed frame (not shown), and a rotor 14 supported inside the stator 12 so as to be rotatable around a central axis CL and concentric with the stator 12. In the following description, the direction along the central axis CL when the rotor 14 rotates in the rotating electric machine 10 is defined as the axial direction, and the direction in which the rotor 14 rotates around the central axis CL is defined as the circumferential direction. The direction perpendicular to the axial direction and the circumferential direction is defined as the radial direction, and the side approaching the central axis CL in the radial direction is defined as the inner side, and the side moving away from the central axis CL is defined as the outer side.

[0011] The stator 12 includes a cylindrical stator core 16 and an armature winding (coil) 18 wound around the stator core 16. The stator core 16 is configured by concentrically stacking a plurality (a large number of sheets) of magnetic material, for example, annular electromagnetic steel sheets such as silicon steel. The stator core 16 has a plurality of slots 20 and teeth 21. The plurality of slots 20 are arranged at approximately equal intervals in the circumferential direction. Each slot 20 opens on the inner peripheral surface of the stator core 16 and extends in the radial direction (radial direction) from the inner peripheral surface. Each slot 20 is continuous over the entire axial length of the stator core 16. By forming the plurality of slots 20, a plurality of teeth 21 (48 in this embodiment, for example) facing the rotor 14 are formed between the slots 20 adjacent to each other in the circumferential direction on the inner peripheral portion of the stator core 16. In other words, each gap between the teeth 21 adjacent to each other in the circumferential direction is configured as a slot 20. As a result, the teeth 21 and the slots 20 are arranged alternately in the circumferential direction.

[0012] The armature windings 18 are wound around the teeth 21 through slots 20. When a current is applied to the armature windings 18, a predetermined interlinkage magnetic flux is formed in the stator 12, specifically, in the teeth 21.

[0013] The rotor 14 is supported at both axial ends by bearings (not shown) and is rotatable together with the shaft (rotating shaft) 22 about the central axis CL. Therefore, the rotor 14 is arranged concentrically with the stator 12, with the outer circumferential surface facing the inner circumferential surface of the stator 12 with a small gap therebetween.

[0014] The rotor 14 includes a rotor core 24 and a permanent magnet 26. The rotor core 24 is substantially cylindrical and has an inner hole 25 that is concentric with the central axis CL. The shaft 22 is inserted and fitted into the inner hole 25, and extends concentrically with the rotor core 24. The inner hole 25 is a hole portion for fitting the shaft 22 and fixing it to the rotor 14. The rotor core 24 is configured by concentrically stacking a plurality (a large number of pieces) of annular core pieces (hereinafter referred to as rotor core pieces) 27 made of a magnetic material, such as silicon steel, and has a plurality of magnetic poles (eight poles in this embodiment, as an example). The rotor core pieces 27 are formed of, for example, an electromagnetic steel plate. The number of magnetic poles is not particularly limited. The magnetic poles are aligned along the outer circumferential surface 24a of the rotor core 24 and face the inner circumferential surface 16a of the stator core 16 with a gap therebetween. Each permanent magnet 26 is provided at a magnetic pole of the rotor core 24 .

[0015] Here, in a cross section of the rotor core 24 perpendicular to the central axis CL as shown in FIG. 1, the d-axis and q-axis are defined as follows. The d-axis is an axis that passes through the central axis CL and the center of each magnetic pole, and extends in the radial direction (radial direction). The q-axis is an axis that passes through the central axis CL and the circumferential end of each magnetic pole, and extends in the radial direction (radial direction), and forms an electrical angle of 90° with respect to the d-axis. The d-axis and q-axis are set alternately in the circumferential direction of the rotor core 24, and at a predetermined phase. One magnetic pole of the rotor core 24 refers to the region between the q-axes (a circumferential angle region of 1 / 8 of a circumference). For this reason, the rotor core 24 is configured with eight poles (magnetic poles). The circumferential center of one magnetic pole is the d-axis.

[0016] 2 is an enlarged view of a portion (one magnetic pole portion) of the rotor of the rotating electric machine shown in FIG. 1. The rotor core 24 has two holes (hereinafter referred to as embedding holes) 34 in each magnetic pole into which a permanent magnet 26 is respectively loaded. In the example shown in FIG. 1 and FIG. 2, a total of 16 embedding holes 34 are arranged, one on each side of each d-axis in the circumferential direction of the rotor core 24, i.e., two for each magnetic pole. Each embedding hole 34 has a shape corresponding to the shape of the permanent magnet 26, and penetrates the rotor core 24 over its entire length in the axial direction. Each embedding hole 34 is loaded with one permanent magnet 26. As a result, two permanent magnets 26 are arranged for each magnetic pole.

[0017] Each embedment hole 34 has a substantially rectangular cross-sectional shape and is inclined with respect to the d-axis. In the cross-section of the rotor core 24, two embedment holes 34 corresponding to one magnetic pole are arranged side by side, for example, in a substantially V-shape. That is, the inner circumferential ends of the two embedment holes 34 are adjacent to the d-axis and face each other with a small gap between them. In the rotor core 24, a narrow magnetic path narrow portion (hereinafter referred to as a center bridge) 36 is formed between the inner circumferential ends of the two embedment holes 34.

[0018] The outer peripheral ends of the two embedding holes 34 are spaced from the d-axis in the circumferential direction of the rotor core 24, and are located near the outer peripheral surface 24a of the rotor core 24 and near the q-axis. As a result, the outer peripheral ends of the embedding holes 34 face the outer peripheral ends of the embedding holes 34 of the adjacent magnetic pole across the q-axis. In the rotor core 24, a narrow magnetic path narrow portion (hereinafter referred to as a top bridge) 38 is formed between the outer peripheral end of each embedding hole 34 and the outer peripheral surface 24a of the rotor core 24. In this way, the two embedding holes 34 are arranged such that the distance from the d-axis gradually increases from the inner peripheral end to the outer peripheral end.

[0019] As shown in FIG. 2, the permanent magnets 26 are loaded into the respective embedding holes 34 and embedded in the rotor core 24. The permanent magnets 26 are formed, for example, in the shape of an elongated flat plate having a rectangular cross section, and have a first surface 26a and a second surface 26b that face each other in parallel, and a pair of side surfaces that face each other. The permanent magnets 26 have a length that is approximately equal to the entire axial length of the rotor core 24. The permanent magnets 26 may be formed, for example, by combining magnets that are divided into a plurality of parts in the axial direction (longitudinal direction). In this case, the total length of the plurality of magnets is set to be approximately equal to the entire axial length of the rotor core 24. The magnetization direction of each permanent magnet 26 is set to be perpendicular to the first surface 26a and the second surface 26b of the permanent magnet 26.

[0020] Each embedding hole 34 has a rectangular loading region 34a corresponding to the cross-sectional shape of the permanent magnet 26, two gaps (an inner circumferential gap 34b and an outer circumferential gap 34c) extending from both longitudinal ends of the loading region 34a, and a pair of protrusions (engaging protrusions) 34d protruding into the embedding hole 34 from the inner circumferential end face 35a of the embedding hole 34 at both longitudinal ends of the loading region 34a.

[0021] The loading area 34a is defined as a space between a rectangular inner end surface 35a and a rectangular outer end surface 35b that faces the inner end surface 35a and is substantially parallel to the inner end surface 35a. The inner gap 34b is defined by a first inner side surface 44a, a second inner side surface 44b, and a third inner side surface 44c. The first inner side surface 44a extends from one end (the end on the d-axis side) of the outer end surface 35b of the loading area 34a and is substantially flush with the outer end surface 35b. The second inner side surface 44b extends from one end (the end on the d-axis side, here the protrusion 34d) of the inner end surface 35a of the loading area 34a toward the d-axis. The third inner side surface 44c spans the extending end of the first inner side surface 44a and the extending end of the second inner side surface 44b, and extends substantially parallel to the d-axis. Both ends of the third inner surface 44c are connected to the first inner surface 44a and the second inner surface 44b via curved surfaces. The inner peripheral side gaps 34b of the two embedding holes 34 are arranged such that the third inner surfaces 44c face each other with the d-axis and the center bridge 36 interposed therebetween.

[0022] The outer periphery side gap 34c is defined by a first inner side surface 46a, a second inner side surface 46b, and a third inner side surface 46c. The first inner side surface 46a extends from the other end of the outer periphery side end surface 35b of the loading area 34a (the end on the outer periphery side surface 24a side of the rotor core 24) and spreads out almost flush with the outer periphery side end surface 35b. The second inner side surface 46b extends from the other end of the inner periphery side end surface 35a of the loading area 34a (the end on the outer periphery side surface 24a side of the rotor core 24, here the protrusion 34d) toward the outer periphery side surface 24a of the rotor core 24 almost parallel to the inner periphery side end surface 35a and spreads out. The third inner side surface 46c straddles the extending end of the first inner side surface 46a and the extending end of the second inner side surface 46b and extends out along the outer periphery side surface 24a of the rotor core 24. Both end portions of the third inner side surface 46c are connected to the first inner side surface 46a and the second inner side surface 46b via curved surfaces. A top bridge 38 is defined between the third inner side surface 46c and the outer circumferential surface 24a of the rotor core 24.

[0023] The inner peripheral gap 34b and the outer peripheral gap 34c function as flux barriers that suppress magnetic flux leakage from both longitudinal ends of the permanent magnet 26 to the rotor core 24, and also contribute to reducing the weight of the rotor core 24.

[0024] Each permanent magnet 26 is loaded in the loading area 34a of the embedding hole 34 so that the first surface 26a faces the outer peripheral end surface 35b and the second surface 26b faces the inner peripheral end surface 35a. The permanent magnet 26 is engaged by a pair of corners abutting the protrusions 34d. This positions the permanent magnet 26 in the loading area 34a. The permanent magnet 26 positioned in the loading area 34a may be fixed to the embedding hole 34 by, for example, an adhesive. As described above, the two permanent magnets 26 located on both sides of each d axis are loaded one by one into two embedding holes 34 arranged side by side in a substantially V-shape, and are arranged side by side in a substantially V-shape corresponding to these embedding holes 34. That is, these two permanent magnets 26 are arranged so that the distance from the d axis gradually increases from the inner peripheral end to the outer peripheral end.

[0025] As described above, each permanent magnet 26 is magnetized in a direction perpendicular to the first surface 26a and the second surface 26b. The two permanent magnets 26 located on both sides of each d-axis, that is, the two permanent magnets 26 constituting one magnetic pole, are arranged so that their magnetization directions are the same. The two permanent magnets 26 located on both sides of each q-axis are arranged so that their magnetization directions are opposite to each other. By arranging the multiple permanent magnets 26 in this manner, the regions on each d-axis on the outer periphery of the rotor core 24 are formed around one magnetic pole, and the regions on each q-axis are formed around an inter-pole portion. As an example, in this embodiment, the rotating electric machine 10 is configured as a permanent magnet embedded rotating electric machine wound in a distributed winding manner with 8 poles (4 pole pairs) and 48 slots, in which the front and back of the N poles and S poles of the permanent magnets 26 are alternately arranged for each adjacent magnetic pole.

[0026] As shown in FIG. 1, the rotor core 24 has a plurality of air gap holes (hollow portions) 30. The air gap holes 30 penetrate the rotor core 24 over the entire axial length. Each air gap hole 30 is located approximately at the center of the rotor core 24 in the radial direction on the q axis, and is provided between two embedded holes 34 of adjacent magnetic poles. In the example shown in FIG. 1, the air gap hole 30 has an approximately circular cross-sectional shape. The air gap hole 30 functions as a flux barrier that makes it difficult for magnetic flux to pass through, and regulates the flow of interlinkage magnetic flux of the stator 12 and the flow of magnetic flux of the permanent magnet 26. In addition, by forming the air gap holes 30, the weight of the rotor core 24 can be reduced.

[0027] Next, the configuration of the rotor core 24 of this embodiment will be further described. FIG. 3 is a perspective view that shows a schematic view of the vicinity of the embedding hole 34 of the rotor core 24. As shown in FIG.

[0028] As described above, the rotor core 24 is configured by concentrically stacking a large number of rotor core pieces 27 made of, for example, electromagnetic steel sheets. As shown in Fig. 3, each of the rotor core pieces 27 has a plurality of thin-walled portions 50 in a portion thereof.

[0029] FIG. 4 is a perspective view showing a schematic example of the configuration of the thin-walled portion 50 in the rotor core piece 27. As shown in FIGS. 3 and 4, each thin-walled portion 50 is a portion of the entire rotor core piece 27 that is thinner than the other portions of the thin-walled portion 50. The thickness of the other portions of the rotor core piece 27 is set to, for example, the sheet thickness of the electromagnetic steel sheet that is the base material. For example, the thin-walled portion 50 is formed by applying a larger pressure (coining) than the other portions when punching out the electromagnetic steel sheet by press working. This causes a difference in thickness between the thin-walled portion 50 and the other portions.

[0030] The thin-walled portion 50 is disposed at a predetermined portion of the rotor core 24. When the rotor 14 rotates at high speed, the permanent magnets 26 loaded in the loading areas 34a of the embedding holes 34 hit the predetermined portion of the rotor core 24 relatively more strongly than other portions due to centrifugal force, and a large load is applied to the predetermined portion. In other words, the thin-walled portion 50 is weaker than the other portions of the rotor core piece 27 as a whole, and is deformable relative to the other portions.

[0031] 1 to 3, each thin portion 50 is disposed on the periphery of the embedding hole 34. In the illustrated example, the thin portion 50 is disposed in a region of the rotor core piece 27 that is continuous along the entire outer peripheral end face 35b of the loading region 34a in the corresponding embedding hole 34. The thin portion 50 has a substantially rectangular shape with the elongated direction being along the outer peripheral end face 35b of the loading region 34a when viewed in the axial direction (direction along the central axis CL). However, the shape is not limited to this.

[0032] As shown in FIG. 4, the thin-walled portion 50 is formed by equally recessing both the first surface 27a and the second surface 27b of the rotor core piece 27. The first surface 27a and the second surface 27b are main surfaces (principal surfaces) constituting the rotor core piece 27. That is, the rotor core piece 27 has a pair of recesses 27c, 27d on the first surface 27a side and the second surface 27b side. These recesses 27c, 27d define the thin-walled portion 50. In the illustrated example, the recesses 27c, 27d are made equal, and the thin-walled portion 50 is a flat plate with a substantially constant thickness. The thickness of the thin-walled portion 50 may be any thickness that allows the thin-walled portion 50 to deform relative to the portion of the rotor core piece 27 other than the thin-walled portion 50.

[0033] 4, the thin-walled portion 50 is connected to the first surface 27a and the second surface 27b via the inclined portions 52. The rotor core piece 27 is gradually thinner in thickness from the first surface 27a and the second surface 27b to the thin-walled portion 50 in accordance with the inclined portions 52. However, as in a first modified example shown in FIG. 5, a step portion 54 may be provided between the thin-walled portion 50a and the first surface 27a and the second surface 27b instead of the inclined portions 52.

[0034] In the example shown in FIG. 4, the thin-walled portion 50 is formed by equally recessing both the first surface 27a and the second surface 27b of the rotor core piece 27, but the recessed degree (depth of recesses 27c, 27d) of the first surface 27a and the second surface 27b may not be equal. For example, as in the second modified example shown in FIG. 6, the recessed degree (depth of recess 27c) of the first surface 27a may be greater than the recessed degree (depth of recess 27d) of the second surface 27b. The thin-walled portion 50b defined by these recesses 27c, 27d is disposed closer to the second surface 27b than to the first surface 27a. Note that, contrary to the second modified example shown in FIG. 6, the recessed degree (depth of recess 27d) of the second surface 27b may be greater than the recessed degree (depth of recess 27c) of the first surface 27a.

[0035] Alternatively, as in the third modified example shown in FIG. 7, only the first surface 27a may have the recess 27c, and the thin-walled portion 50c may be defined only by the recess 27c. In this case, the second surface 27b does not have a recess and is a flat surface over the entire surface. In other words, the thin-walled portion 50c forms a part of the second surface 27b corresponding to the position of the recess 27c of the first surface 27a, and is flush with the second surface 27b. Note that, contrary to the third modified example shown in FIG. 7, only the second surface 27b may have the recess 27d, and the thin-walled portion may be defined only by the recess 27d. In this case, the first surface 27a is a flat surface over the entire surface.

[0036] 6 and 7 show the form of the thin-walled portions 50b, 50c in which a step portion 54 is formed between the first surface 27a and the second surface 27b, similar to the first modified example shown in Fig. 5. However, in the second and third modified examples shown in Fig. 6 and 7, the thin-walled portions 50b, 50c may be connected to the first surface 27a and the second surface 27b via the inclined portions 52, respectively, as in the example shown in Fig. 4.

[0037] Furthermore, the shape and arrangement of the thin-walled portions as viewed from the axial direction (the direction along the central axis CL) are not limited to the example shown in Fig. 2. For example, the thin-walled portions may have shapes and arrangements as shown in the fourth to ninth modified examples shown in Figs. 8 to 13. In the above-mentioned first to third modified examples and the fourth to ninth modified examples described below, the configurations of the rotor core pieces other than the thin-walled portions, and further the rotor and stator, are the same as those of the rotating electric machine 10 according to the first embodiment shown in Figs. 1 to 4, and the configurations shown in these figures are applied.

[0038] In the fourth modified example shown in Fig. 8, the thin-walled portion 50d has a generally rectangular shape with its elongated direction along the outer peripheral end face 35b of the loading region 34a when viewed in the axial direction, similar to the example shown in Fig. 2. Meanwhile, the thin-walled portion 50d is not disposed on the entire outer peripheral end face 35b of the loading region 34a in the embedding hole 34, but is disposed only on a portion of the outer peripheral end face 35b close to the first inner side surface 44a of the inner peripheral gap 34b.

[0039] In the fifth modified example shown in FIG. 9, the thin-walled portion 50e is disposed on the protrusion 341d adjacent to the outer periphery side gap 34c among the pair of protrusions 34d of the embedding hole 34, in other words, the protrusion 341d located between the second inner side surface 46b of the outer periphery side gap 34c and the inner periphery side end surface 35a of the loading area 34a, and in its vicinity. The thin-walled portion 50e is disposed in an area surrounded by the contour line 34e of the protrusion 341d and a predetermined boundary line 34f when viewed from the axial direction. The contour line 34e is a curve that defines the outer edge of the protrusion 341d. The boundary line 34f is a curve that is concavely curved in the opposite direction to the contour line 34e that is a substantially inverted version of the contour line 34e, and connects the second inner side surface 46b and the inner periphery side end surface 35a.

[0040] In a sixth modified example shown in Fig. 10, both the thin-walled portion 50d of the fourth modified example shown in Fig. 8 and the thin-walled portion 50e of the fifth modified example shown in Fig. 9 are arranged on a rotor core piece 27. That is, in the sixth modified example, two thin-walled portions 50d, 50e are arranged on the periphery of each embedding hole 34.

[0041] In the seventh modified example shown in FIG. 11, the thin-walled portion 50f is disposed in the region of the rotor core piece 27 that is continuous along the entire outer peripheral end surface 35b of the loading area 34a of the embedding hole 34, in the same manner as in the example shown in FIG. 2, among the peripheral portion of the embedding hole 34. Meanwhile, the thin-walled portion 50f is formed in a substantially trapezoidal shape with a height that is the length along the outer peripheral end surface 35b of the loading area 34a when viewed from the axial direction. In the illustrated example, the upper base of the substantially trapezoidal thin-walled portion 50f is located on the outer peripheral gap 34c side of the embedding hole 34, and the lower base, which is larger than the upper base, is located on the inner peripheral gap 34b side of the embedding hole 34, and one leg portion extends along the outer peripheral end surface 35b. In the illustrated example, the thin-walled portion 50f is formed in a trapezoidal shape with the lower base larger than the upper base. However, the trapezoid may be formed in a reverse manner with the upper base larger than the lower base.

[0042] In the eighth modified example shown in Fig. 12, the thin-walled portion 50g is disposed in a region of the rotor core piece 27 that is continuous along the entire outer circumferential end surface 35b of the loading region 34a of the embedding hole 34, in the same manner as in the example shown in Fig. 2, among the peripheral portion of the embedding hole 34. On the other hand, the thin-walled portion 50g has a region 501g that is a convexly curved and expanded region on the inner circumferential gap 34b side of the embedding hole 34 in the thin-walled portion 50 shown in Fig. 2, as viewed in the axial direction. A region 502g of the thin-walled portion 50g other than the region 501g (a region on the outer circumferential gap 34c side of the embedding hole 34 in the thin-walled portion 50g) has a substantially rectangular shape with the elongated direction being along the outer circumferential end surface 35b of the embedding hole 34 in the thin-walled portion 50g, as in the thin-walled portion 50 shown in Fig. 2, as viewed in the axial direction.

[0043] In the rotor core pieces 27 according to the first embodiment (FIG. 2) and the first to eighth modified examples (FIGS. 5 to 12) described above, the thin-walled portions 50, 50a to 50g arranged on the periphery of each of the two embedding holes 34 corresponding to one magnetic pole of the rotor core 24 are arranged symmetrically with respect to the d axis. However, these thin-walled portions 50, 50a to 50g may be arranged asymmetrically with respect to the d axis. FIG. 13 shows a modified example (ninth modified example) in which the thin-walled portions are arranged asymmetrically with respect to the d axis in this manner.

[0044] In the ninth modified example shown in FIG. 13, the thin-walled portion 50 of the first embodiment shown in FIG. 2 and the thin-walled portion 50e of the fifth modified example shown in FIG. 9 are arranged on one side across the d axis. In contrast, only the thin-walled portion 50e of the fifth modified example shown in FIG. 9 is arranged on the other side across the d axis. Note that the arrangement (combination) of the thin-walled portions asymmetrical with respect to the d axis is not limited to the illustrated example. For example, the thin-walled portion 50 of the first embodiment shown in FIG. 2, the thin-walled portion 50d of the fourth modified example shown in FIG. 8, the thin-walled portion 50e of the fifth modified example shown in FIG. 9, the thin-walled portion 50f of the seventh modified example shown in FIG. 11, and the thin-walled portion 50g of the eighth modified example shown in FIG. 12 may be arbitrarily combined and arranged so as to be asymmetrical with respect to the d axis.

[0045] According to the first embodiment (FIGS. 2 to 4) and the first to ninth modified examples (FIGS. 5 to 13), the following effects are achieved. These effects are described with reference to FIG. 14 and FIG. 15. FIG. 14 and FIG. 15 show a schematic diagram of a contact state between the permanent magnet 26 loaded in the loading area 34a of the embedding hole 34 of the rotor core 24 and the thin-walled portion 50 of each of the laminated rotor core pieces 27. FIG. 14 is a schematic diagram showing a state (initial state) in which the permanent magnet 26 is loaded in the loading area 34a. FIG. 15 is a schematic diagram showing a state when the rotor 14 rotates at high speed and centrifugal force acts thereon.

[0046] As shown in FIG. 14, the positions of the tip portions 501a, 502a, 503a of the thin-walled portions 50 (501, 502, 503) of the laminated rotor core pieces 27 (271, 272, 273 in the illustrated example) may be shifted due to manufacturing errors within the tolerance. Note that the shift is exaggerated in FIG. 14 for ease of understanding. In the rotor core 24 formed by the laminated rotor core pieces 271, 272, 273, the tip portions 501a, 502a, 503a form the outer peripheral end surface 35b of the loading area 34a of the embedding hole 34 (see FIG. 3). The outer peripheral end surface 35b of the loading area 34a faces the first surface 26a of the permanent magnet 26 loaded in the loading area 34a.

[0047] In the illustrated example, that is, in a state where the permanent magnet 26 is loaded in the loading area 34a (initial state), the tip 502a of the thin-walled portion 502, the tip 501a of the thin-walled portion 501, and the tip 503a of the thin-walled portion 503 protrude from the loading area 34a in this order. Of these, the tip 502a of the thin-walled portion 502 is in contact with the first surface 26a of the permanent magnet 26. On the other hand, neither the tip 501a of the thin-walled portion 501 nor the tip 503a of the thin-walled portion 503 is in contact with the first surface 26a of the permanent magnet 26. The opposing distance between the tip 501a and the first surface 26a is narrower than the opposing distance between the tip 503a and the first surface 26a.

[0048] When the rotor 14 rotates at high speed and centrifugal force acts on the permanent magnets 26, the permanent magnets 26 are swung toward the outer peripheral end face 35b of the loading area 34a. In the example shown in Fig. 15, the permanent magnets 26 are displaced toward the outer peripheral end face 35b, specifically, toward the tips 501a, 502a, and 503a of the thin-walled portions 501, 502, and 503, from the initial state shown in Fig. 14.

[0049] As the permanent magnet 26 is displaced, the tip 501a of the thin-walled portion 501 comes into contact with the first surface 26a of the permanent magnet 26, as shown in FIG. 15. During this time, centrifugal force is applied to the thin-walled portion 502, so that the thin-walled portion 502 starts to deform due to the centrifugal force. Then, the tip 503a of the thin-walled portion 503 comes into contact with the first surface 26a. During this time, centrifugal force is applied to the thin-walled portion 501 in addition to the thin-walled portion 502, so that the thin-walled portion 502 is deformed even more due to the centrifugal force, and the thin-walled portion 501 also starts to deform. Then, as shown in FIG. 15, the tip portions 501a and 502a of the thin-walled portions 501 and 502 are in contact with the first surface 26a while the thin-walled portion 503 is not deformed and the tip portion 503a is in contact with the first surface 26a.

[0050] Since the thin-walled portions 501, 502 deform and act as cushions (shock-absorbing materials), the load acting due to centrifugal force on portions of the rotor core 24 other than the thin-walled portions 501, 502 of the rotor core pieces 271, 272 can be reduced. Therefore, the load due to centrifugal force transmitted to the center bridge 36 and the top bridge 38 of the rotor core 24, for example, can be alleviated. This suppresses the concentration of the load on the outer periphery of the permanent magnet 26 when the rotor 14 rotates at high speed, and prevents the center bridge 36 and the top bridge 38 from breaking.

[0051] As described above, in the first embodiment and the first to ninth modified examples, the thin-walled portions 50, 50a to 50g are disposed at the portions where the permanent magnets 26 loaded in the loading areas 34a of the embedding holes 34 hit relatively stronger than other portions due to centrifugal force when the rotor 14 rotates at high speed, and where a large load is applied. This makes the thin-walled portions 50, 50a to 50g weaker than the portions other than the thin-walled portions 50, 50a to 50g in the entire rotor core piece 27, and allows the portions to be deformed. As a result, the concentration of the load on the outer periphery of the permanent magnets 26 during high speed rotation of the rotor 14 can be suppressed, and the durability of the rotor core 24 against the centrifugal force during high speed rotation can be improved. In addition, the impact of the permanent magnets 26 can be distributed to the thin-walled portions 50, 50a to 50g of the laminated rotor core pieces 27 without being concentrated, so that damage to the permanent magnets 26 can be suppressed.

[0052] Here, in the first embodiment (FIGS. 2 to 4) and the first to ninth modified examples (FIGS. 5 to 13), the thin-walled parts 50, 50a to 50g have a flat plate-like cross-sectional shape. The cross-section here is a cross-section in a plane (hereinafter referred to as a predetermined plane) along the direction in which the outer peripheral end face 35b of the loading area 34a and the first face 26a of the permanent magnet 26 loaded in the loading area 34a face each other. In order to further increase the deformability of the thin-walled parts 50, 50a to 50g, these shapes may be other than a flat plate-like shape, in short, a shape that is easier to deform. Hereinafter, such shapes of the thin-walled parts other than a flat plate-like shape will be described as the second embodiment and the third embodiment. In the second embodiment and the third embodiment, the configurations of the rotor core pieces other than the thin-walled parts, and further the rotor and the stator are the same as those of the rotating electric machine 10 according to the first embodiment shown in FIGS. 1 to 4, and the configurations shown in these figures are applied.

[0053] Second embodiment FIG. 16 is a diagram that shows a schematic cross section of the thin-walled portion 50h in a predetermined plane according to this embodiment. As shown in FIG. 16, in this embodiment, the thin-walled portion 50h has a plate-like cross section in a predetermined plane that is curved in a wave shape. By making the thin-walled portion 50h in such a wave shape, when the rotor 14 rotates at high speed and centrifugal force acts on the permanent magnet 26, and the permanent magnet 26 comes into contact with the thin-walled portion 50h, stress against the centrifugal force can be concentrated on the peaks 56 and valleys 57 of the wave-shaped thin-walled portion 50h. Therefore, the thin-walled portion 50h can be actively deformed starting from the peaks 56 and valleys 57 of the thin-walled portion 50h. Therefore, the thin-walled portion 50h can be easily deformed compared to the thin-walled portions 50, 50a to 50g, for example, whose cross section is a flat plate shape. The number of peaks 56 and valleys 57 of the thin-walled portion 50h is not limited to the illustrated example.

[0054] (Third embodiment) FIG. 17 is a diagram that shows a schematic cross section of the thin-walled portion 50i in a predetermined plane according to this embodiment. As shown in FIG. 17, in this embodiment, the thin-walled portion 50i has a plate-like cross section in a predetermined plane that is bent into a substantially V-shape. That is, the thin-walled portion 50i has a bent portion 58 in which the cross section in the predetermined plane is bent into a substantially V-shape. In the illustrated example, the thin-walled portion 50i has one bent portion 58, and the entire cross section in the predetermined plane is a plate-like cross section bent into a substantially V-shape. By making the thin-walled portion 50i into such a substantially V-shape, when the rotor 14 rotates at high speed and centrifugal force acts on the permanent magnet 26, and the permanent magnet 26 and the thin-walled portion 50i come into contact with each other, stress against the centrifugal force can be concentrated in the bent portion 58 of the substantially V-shaped thin-walled portion 50i. Therefore, the thin-walled portion 50i can be actively deformed starting from the bent portion 58 of the thin-walled portion 50i. Therefore, the thin portion 50i can be easily deformed compared to the thin portions 50, 50a to 50g each having a flat plate-like cross section.The number and bending angle of the bent portions 58 of the thin portion 50i are not limited to those shown in the figures.

[0055] Although several embodiments of the present invention have been described above, the above-mentioned embodiments and their modifications are presented as examples and are not intended to limit the scope of the invention. Such novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0056] 10... rotating machine, 12... stator, 14... rotor, 16... stator core, 16a... inner peripheral surface, 18... armature winding (coil), 20... slot, 21... teeth, 22... shaft (rotating shaft), 24... rotor core, 24a... outer peripheral surface, 25... inner hole, 26... permanent magnet, 26a... first surface, 26b... second surface, 27, 271, 272, 273... core piece (rotor core piece), 27a... first surface, 27b... second surface, 27c, 27d... recess, 30... gap hole, 34... hole portion (embedding hole), 34a... loading area, 34b... inner peripheral gap, 34c... outer peripheral gap, 34d, 341d... protrusion (engagement protrusion), 34e... Contour line, 34f...boundary line, 35a...inner end face, 35b...outer end face, 36...narrow magnetic path portion (center bridge), 38...narrow magnetic path portion (top bridge), 44a...first inner surface, 44b...second inner surface, 44c...third inner surface, 46a...first inner surface, 46b...second inner surface, 46c...third inner surface, 50, 50a, 50b, 50c, 50d, 50e, 50f, 50g, 50h, 50i, 501, 502, 503...thin-walled portion, 52...inclined portion, 54...step portion, 56...ridge portion, 57...valley portion, 58...bent portion, 501a, 502a, 503a...tip portion, 501g...area, CL...central axis.

Claims

1. a stator having a cylindrical stator core in which teeth and slots are alternately arranged in a circumferential direction, and an armature winding wound around the teeth and passing through the slots; a rotor having a rotor core having a plurality of magnetic poles arranged along an outer circumferential surface facing an inner circumferential surface of the stator core with a gap therebetween, and a plurality of permanent magnets provided on each of the magnetic poles, the rotor being provided rotatably about a central axis that is concentric with the stator core, In a cross section of the rotor core perpendicular to the central axis, an axis extending radially through the circumferential ends of the magnetic poles and the central axis is defined as a q-axis, and an axis electrically spaced 90 degrees from the q-axis in the circumferential direction is defined as a d-axis. the rotor core is configured by stacking a plurality of thin-plate-shaped core pieces concentrically about the central axis, and has two embedding holes provided on both sides of the d-axis in each of the magnetic poles, into which the permanent magnets are respectively inserted; Each of the plurality of core pieces has a thin portion that is thinner than other portions throughout the entirety and is deformable relative to the other portions. Rotating electric motor.

2. The thin-walled portion is disposed in a portion of the core piece against which the permanent magnet loaded in the embedding hole hits relatively more strongly due to centrifugal force than the portion other than the thin-walled portion when the rotor rotates. The rotating electric machine according to claim 1 .

3. The thin portion is disposed on the periphery of the embedment hole adjacent to a mounting region of the permanent magnet in the embedment hole. The rotating electric machine according to claim 2 .

4. The thin-walled portion has a wavy, curved plate-like cross-sectional shape in a plane along a direction in which an outer peripheral end face of the loading area and the permanent magnet loaded in the loading area face each other. The rotating electric machine according to claim 3 .

5. The thin-walled portion has a bent portion whose cross section in a plane along a direction in which an outer peripheral end face of the loading area and the permanent magnet loaded in the loading area face each other is substantially V-shaped. The rotating electric machine according to claim 3 .

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