JP2023094105A - Rotor, and rotary electric machine - Google Patents

Abstract

To provide a rotor, and a rotary electric machine which can stably hold a magnet.SOLUTION: One embodiment of a rotor of the present invention comprises: a rotor core 32 extending along an axial direction centering on a center axis and provided with a plurality of magnet holes 38 extending in the axial direction; and a plurality of magnetic poles having a plurality of magnets 36 arranged in the magnet holes. Each of the plurality of magnet holes includes a pair of first magnet holes 38A extending in a radial direction and symmetrically arranged in a circumferential direction to a magnetic pole center line L passing through the center of the magnetic poles. Each inner peripheral surface of the magnet hole comprises a first inner surface 51 located on the magnetic pole center line side to the magnet to be accommodated. The first inner surface comprises: a first curved part 51a curved in a recessed shape; and a second curved part 51b connected to an end inside the radial direction of the first curved part and curved in the recessed shape. A curvature radius of the first curved part is larger than a curvature radius of the second curved part. The first inner surface is most close to the magnetic pole center line at the first curved part.SELECTED DRAWING: Figure 4

Description

The present invention relates to rotors and rotating electric machines.

2. Description of the Related Art Development of rotating electric machines for driving vehicles, such as electric vehicles and hybrid vehicles, is underway in various places. Since these rotating electric machines require a high rotational speed, a large force is applied to the rotor core that holds the magnets. Therefore, there is a demand for a rotor core that can stably hold a magnet even during high-speed rotation. Patent Literature 1 discloses a structure that relieves stress in a bridge portion when magnets are arranged in a V shape.

WO2017/038311

Conventional rotor cores have corners at the edges of the bridges. Therefore, when the rotor rotates at a high speed and a large tensile stress is applied to the bridge portions, there is a risk of stress concentration occurring at the corner portions and damage to the bridge portions.

An object of the present invention is to provide a rotor and a rotating electrical machine that can stably hold a magnet.

According to one aspect of the rotor of the present invention, a rotor core is provided with a plurality of magnet holes extending in the axial direction around a central axis, and a plurality of magnets are arranged in the magnet holes. and a magnetic pole. The plurality of magnet holes includes a pair of first magnet holes extending in the radial direction and arranged symmetrically in the circumferential direction with respect to a magnetic pole center line passing through the centers of the magnetic poles. The inner peripheral surface of the magnet hole has a first inner surface located on the magnetic pole center line side with respect to the magnet to be accommodated. The first inner surface has a concavely curved first curved portion and a concavely curved second curved portion connected to a radially inner end portion of the first curved portion. The radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion. The first inner surface is closest to the pole centerline at the first bend.

One aspect of the rotating electric machine of the present invention includes the rotor and a stator arranged radially outside the rotor.

ADVANTAGE OF THE INVENTION According to one aspect of this invention, the rotor which can hold|maintain a magnet stably, and a rotary electric machine can be provided.

FIG. 1 is a schematic cross-sectional view of a rotating electric machine according to one embodiment. FIG. 2 is a cross-sectional view of the rotor 30 of one embodiment. FIG. 3 is a partially enlarged view of FIG. 2 showing one magnetic pole. FIG. 4 is a partially enlarged view of FIG. 3 showing the vicinity of the first inner surface of the inner magnet hole (first magnet hole). FIG. 5 is a partial cross-sectional view of a modified rotor.

Each figure shows the central axis J as appropriate. A central axis J is a virtual line passing through the center of the rotating electric machine in the following embodiments. The Z-axis appropriately shown in each figure indicates the direction in which the central axis J extends. In the following description, the axial direction of the central axis J, that is, the direction parallel to the Z-axis is simply referred to as the "axial direction", and the radial direction around the central axis J is simply referred to as the "radial direction". is simply referred to as the "circumferential direction".

An arrow .theta. appropriately shown in the figure indicates the circumferential direction. In the following description, the side that advances counterclockwise about the center axis J when viewed from the axial direction, that is, the side to which the arrow θ points (+θ side) is referred to as the “one side in the circumferential direction”, and the side that advances clockwise, That is, the opposite side (−θ side) to the side to which the arrow θ is directed is called the “other side in the circumferential direction”.

(Rotating electric machine)
FIG. 1 is a schematic cross-sectional view of a rotating electric machine 10. As shown in FIG.
The rotary electric machine 10 of this embodiment is an inner rotor type rotary electric machine. In this embodiment, the rotating electric machine 10 is a motor. The rotating electric machine 10 may be a generator.

The rotating electric machine 10 includes a rotor 30, a stator 40, and a housing 9 that accommodates the rotor 30 and the stator 40 inside.

(stator)
The stator 40 faces the rotor 30 with a gap therebetween. The stator 40 is positioned radially outside the rotor 30 . The stator 40 has a stator core 41 , insulators 42 a and multiple coils 42 . The stator core 41 has an annular core back 41a and a plurality of teeth 41b protruding radially inward from the core back 41a. The plurality of coils 42 are attached to the plurality of teeth 41b via insulators 42a.

(rotor)
The rotor 30 is rotatable around a central axis J extending in the axial direction. The rotor 30 has a shaft 31 , a rotor core 32 and a plurality of magnets 36 . The shaft 31 has a columnar shape extending in the axial direction around the central axis J. As shown in FIG.

The rotor 30 has an annular rotor core 32 centered on the central axis J, a plurality of magnets 36, and a shaft 31 (not shown in FIG. 2).

FIG. 2 is a cross-sectional view of the rotor 30. As shown in FIG.
The rotor 30 has a plurality of magnetic poles 3 arranged along the circumferential direction. The rotor 30 of this embodiment has eight magnetic poles 3 . One magnetic pole 3 includes four magnets 36 . The four magnets 36 of one magnetic pole 3 are arranged in mirror symmetry with the magnetic pole center line L as the center. Here, the magnetic pole center line L is a virtual line passing through the circumferential center of the magnetic pole 3 and the center axis line J and extending in the radial direction. In this embodiment, the magnetic pole center line L is substantially parallel to the d-axis, which is the direction of the main magnetic flux.

(rotor core)
The rotor core 32 extends axially around the central axis J. As shown in FIG. The rotor core 32 has a central hole 32a that axially penetrates the rotor core 32 . The central hole 32a has a substantially circular shape centered on the central axis J. As shown in FIG. A shaft 31 (see FIG. 1) is axially passed through the central hole 32a.

The rotor core 32 is made of magnetic material. Although not shown, the rotor core 32 has a plurality of laminations stacked in the axial direction. A lamination is a plate-like member. The plate surface of the lamination faces the axial direction. The lamination has a substantially annular plate shape centered on the central axis J. As shown in FIG. The lamination is, for example, electromagnetic steel sheets.

A plurality of magnet holes 38 are provided in the rotor core 32 . Each magnet hole 38 is arranged in a portion of the rotor core 32 other than the central hole 32a. More specifically, when viewed from the axial direction, the magnet holes 38 are arranged radially outside and circumferentially spaced apart from the central hole 32a. Each magnet hole 38 axially penetrates the rotor core 32 . The magnet hole 38 extends axially in a uniform shape. One magnet 36 is arranged in each magnet hole 38 . The magnet 36 is fixed to the inner surface of the magnet hole 38 by known means such as resin molding, crimping, and adhesion.

FIG. 3 is a partially enlarged view showing the periphery of one magnetic pole 3 in FIG.
The multiple magnet holes 38 include an inner magnet hole (first magnet hole) 38A and an outer magnet hole 38B. The outer magnet hole 38B is arranged radially outside the inner magnet hole 38A. The number of inner magnet holes 38A and the number of outer magnet holes 38B are the same.

The pair of inner magnet holes 38A are arranged symmetrically with respect to the magnetic pole center line L in the circumferential direction. Similarly, the pair of outer magnet holes 38B are arranged symmetrically with respect to the magnetic pole center line L in the circumferential direction. The outer magnet hole 38B is arranged radially outside the inner magnet hole 38A.

A total of four magnets 36 arranged in a pair of inner magnet holes 38A and a pair of outer magnet holes 38B arranged with respect to the magnetic pole center line L constitute one magnetic pole 3 . In the following description, the four magnet holes 38 in which the magnets 36 forming one magnetic pole 3 are arranged are referred to as a set S of magnet holes 38 .

Among the pair of inner magnet holes 38A of one set S, one on the one circumferential side (+θ side) of the magnetic pole center line L increases radially outward when viewed from the axial direction. ). Of the pair of inner magnet holes 38A of one set S, the other side (-.theta. θ side). That is, the circumferential distance between a pair of inner magnet holes 38A included in one set S gradually increases radially outward.

Of the pair of outer magnet holes 38B of one set S, one on the one circumferential side (+θ side) of the magnetic pole center line L increases radially outward when viewed from the axial direction. ). Of the pair of outer magnet holes 38B of one set S, the other on the other side in the circumferential direction (−θ side) of the magnetic pole center line L is arranged on the other side in the circumferential direction (− θ side). That is, the circumferential distance between a pair of outer magnet holes 38B included in one set S gradually increases radially outward.

A first bridge portion 33 of the rotor core 32 is provided between a pair of inner magnet holes 38A arranged symmetrically with respect to the magnetic pole center line L. As shown in FIG. Similarly, a second bridge portion 34 of the rotor core 32 is provided between a pair of outer magnet holes 38B arranged symmetrically with respect to the magnetic pole center line L. As shown in FIG. That is, the rotor core 32 has a first bridge portion 33 and a second bridge portion 34 . The first bridge portion 33 and the second bridge portion 34 extend radially along the magnetic pole center line L, respectively. The centers in the circumferential direction of the first bridge portion 33 and the second bridge portion 34 overlap the magnetic pole center line L when viewed from the axial direction.

A flux barrier portion 38e is provided in the inner magnet hole 38A and the outer magnet hole 38B. The flux barrier portions 38e are arranged on both sides of the magnet 36 to be housed when viewed from the axial direction. In this specification, the term “flux barrier portion” means a portion capable of suppressing the flow of magnetic flux. In other words, it is difficult for the magnetic flux to pass through the flux barrier portion 38e. The flux barrier portion 38e is not particularly limited as long as it can suppress the flow of magnetic flux, and may include a void portion or a non-magnetic portion such as a resin portion. In the present embodiment, the flux barrier portion 38e is a gap formed by a hole penetrating the rotor core 32 in the axial direction.

One magnet 36 is arranged in each magnet hole 38 . The type of magnet 36 is not particularly limited. The magnet 36 may be, for example, a neodymium magnet or a ferrite magnet. In this embodiment, the magnet 36 has a rectangular parallelepiped shape that is long in the axial direction. Therefore, the magnet 36 has a rectangular shape when viewed from the axial direction. The magnet 36 extends, for example, from one axial end of the rotor core 32 to the other axial end. The axial dimension of the magnet 36 may be shorter than the axial dimension of the rotor core 32 (the axial dimension of the magnet hole 38). Also, the shape of the magnet 36 is not limited to that described above.

Four magnets 36 are arranged on one magnetic pole 3 . In the following description, the magnets 36 arranged in the inner magnet holes 38A are called inner magnets 36A. Similarly, the magnets 36 arranged in the outer magnet holes 38B are called outer magnets 36B. Magnetic pole 3 includes two inner magnets 36A and two outer magnets 36B.

In one magnetic pole 3, the two inner magnets 36A are arranged symmetrically in the circumferential direction with respect to the magnetic pole centerline L. As shown in FIG. In one magnetic pole 3, the two inner magnets 36A are spaced apart from each other as they extend radially outward. In one magnetic pole 3, the two outer magnets 36B are arranged symmetrically in the circumferential direction with respect to the magnetic pole center line L radially inside the inner magnet 36A. In one magnetic pole 3, the two outer magnets 36B are spaced apart from each other as they go radially outward.

The magnetization direction of the inner magnet 36A and the outer magnet 36B is the thickness direction. A pair of inner magnets 36A and a pair of outer magnet holes 38B, which constitute one magnetic pole 3, face the same poles radially outward. For example, if the surface of the inner magnet 36A facing radially outward is the N pole (or S pole), the surface of the outer magnet hole 38B facing radially outward is also the N pole (or S pole).

(inner magnet hole)
Next, the specific shape of the inner magnet hole 38A and its periphery will be described.
The inner peripheral surface of the inner magnet hole 38A has a first inner surface 51, a second inner surface 52, a third inner surface 53, a fourth inner surface 54, and a pair of protrusions 58 and 59.

The first inner side surface 51 is the inner side surface of one flux barrier portion 38e arranged on the magnetic pole center line L side. The first inner side surface 51 is positioned on the magnetic pole center line L side with respect to the inner magnet 36A housed in the inner magnet hole 38A.

The second inner surface 52 extends linearly along the circumferential direction. The second inner surface 52 faces radially outward. That is, the second inner side surface 52 is positioned radially inward with respect to the inner magnet 36A accommodated in the inner magnet hole 38A.

The third inner surface 53 extends linearly along the circumferential direction. The third inner surface 53 faces radially inward. That is, the third inner side surface 53 is positioned radially outwardly of the inner magnet 36A accommodated in the inner magnet hole 38A. The third inner side surface 53 faces the second inner side surface 52 . The inner magnet 36A is arranged between the second inner surface 52 and the third inner surface 53. As shown in FIG.

The fourth inner surface 54 is the inner surface of the flux barrier portion 38e located on the side opposite to the magnetic pole center line L side. The fourth inner surface 54 is located on the opposite side of the magnetic pole centerline L with respect to the inner magnet 36A accommodated in the inner magnet hole 38A.

A pair of protrusions 58 and 59 are provided on the inner peripheral surface of the inner magnet hole 38A. The pair of protrusions 58 and 59 are arranged at both ends of the second inner side surface 52 when viewed in the axial direction. Therefore, of the pair of protrusions 58 and 59, one protrusion 59 is positioned between the first inner side surface 51 and the second inner side surface 52, and the other protrusion 58 is located between the fourth inner side surface 54 and the second inner side surface 54. It is positioned between the inner surface 52 . The pair of protrusions 58 and 59 protrude from the second inner surface 52 side toward the third inner surface 53 side. That is, the pair of protrusions 58 and 59 protrude radially outward. The pair of protrusions 58 and 59 extend in a stripe shape along the axial direction. The inner magnet 36A is arranged between the pair of projections 58,59.

FIG. 4 is a partially enlarged view of FIG. 3 showing the vicinity of the first inner side surface 51 of the inner magnet hole 38A.
A first inner side surface 51 of the inner magnet hole 38A is concavely curved toward the magnetic pole center line L side. Therefore, the first bridge portion 33 arranged between the pair of inner magnet holes 38A has a symmetrically constricted shape with the magnetic pole center line L as the center.

The first inner side surface 51 of the inner magnet hole 38A has a first curved portion 51a, a second curved portion 51b, and a third curved portion 51c. The first curved portion 51a, the second curved portion 51b, and the third curved portion 51c curve concavely. The radii of curvature of the first curved portion 51a, the second curved portion 51b, and the third curved portion 51c are different from each other. The first curved portion 51a, the second curved portion 51b, and the third curved portion 51c are connected radially inward in this order. The second curved portion 51b is connected to the radially inner side of the first curved portion 51a. The third curved portion 51 c connects between the second curved portion 51 b and the protrusion 59 .

In the following description, the boundary portion between the first curved portion 51a and the second curved portion 51b is called a first boundary portion 55a. A boundary portion between the second curved portion 51b and the third curved portion 51c is called a second boundary portion 55b. A boundary portion between the third curved portion 51c and the projecting portion 59 is called a third boundary portion 55c. A boundary portion between the first curved portion 51a and the third inner side surface 53 is called a fourth boundary portion 55d.

In this embodiment, the curvature radius R1 of the first curved portion 51a is larger than the curvature radius R2 of the second curved portion 51b. Also, the radius of curvature R2 of the second curved portion 51b is larger than the radius of curvature R3 of the third curved portion 51c. Therefore, the radius of curvature of the first inner side surface 51 is the largest at the first curved portion 51a. As an example, the radius of curvature R1 of the first curved portion 51a of this embodiment is 3.5 mm, the radius of curvature R2 of the second curved portion 51b is 2.0 mm, and the radius of curvature R3 of the third curved portion 51c is 0. .8 mm.

The first inner side surface 51 is closest to the magnetic pole center line L at the first curved portion 51a. Therefore, the thinnest portion 33a of the first bridge portion 33 is positioned between the first curved portions 51a of the pair of inner magnet holes 38A. A boundary portion (first boundary portion 55 a ) between the first curved portion 51 a and the second curved portion 51 b is positioned radially inward of the smallest portion 33 a of the first bridge portion 33 .

When the motor 1 is energized to rotate the rotor 30, the magnet 36 is given magnetic force drawn from the coil 42 of the stator 40 and centrifugal force due to the rotation. Therefore, when the motor 1 is driven, the magnets 36 of the rotor 30 are applied with radially outward force. A radially outward force applied to the magnets 36 is supported by the first bridge portions 33 of the rotor core 32 . Therefore, tensile stress is applied to the first bridge portion 33 when the motor 1 is started.

According to the present embodiment, since the entire first inner side surface 51 is curved in a concave shape, corner portions are not provided as compared with the case where the first inner side surface extends linearly. Therefore, the stress can be dispersed over the entire first inner side surface 51, and stress concentration can be suppressed. Thereby, the strength of the first bridge portion 33 can be increased, and even if the rotor 30 rotates at a high speed and a large force is applied to the inner magnets 36A, the rotor core 32 can stably support the inner magnets 36A.

According to this embodiment, the first bridge portion 33 is located between the first curved portions 51a having the largest curvature radius. Therefore, a large radius of curvature can be ensured at the closest portion to suppress stress concentration, the strength of the first bridge portion 33 can be increased, and the magnet 36 can be stably supported by the rotor core 32 .

Further, according to the first inner side surface 51 of the present embodiment, the second curved portion 51b having a radius of curvature smaller than that of the first curved portion 51a is provided radially inward of the first curved portion 51a. Therefore, the entire first inner side surface 51 can be smoothly curved to connect the second inner side surface 52 and the protrusion 59 while the first curved portion 51a is made sufficiently large. Accordingly, the first inner side surface 51 is not provided with corners, and stress concentration on the first bridge portion 33 can be suppressed.

In the present embodiment, the curvature radius R1 of the first curved portion 51a is preferably 1.5 times or more, more preferably 2.0 times or more, the curvature radius R2 of the second curved portion 51b. By setting the ratio between the radius of curvature R1 of the first curved portion 51a and the radius of curvature R2 of the second curved portion 51b within the above range, stress concentration on the first bridge portion 33 can be suppressed more effectively.

In this embodiment, the first inner side surface 51 is closest to the central axis J in the second curved portion. Therefore, the boundary portion (second boundary portion 55b) between the second curved portion 51b and the third curved portion 51c is located closer to the inner magnet 36A than the inner end portion 55p where the first inner side surface 51 is closest to the radially inner side. .

The radially outward force of the inner magnet 36A is supported by the region (first bridge portion 33) sandwiched between the pair of inner magnet holes 38A. Therefore, the tensile stress accompanying the support of the inner magnet 36A is applied to the region sandwiched between the pair of inner magnet holes 38A. That is, the region to which the tensile stress is applied is the region closer to the magnetic pole center line L than the inner end portion 55p where the first inner side surface 51 is closest to the radially inner side. According to this embodiment, the third curved portion 51c having a larger radius of curvature than the second curved portion 51b can be arranged closer to the inner magnet 36A than the inner end portion 55p to which no tensile stress is applied. As a result, concentration of stress on the third curved portion 51c can be suppressed.

In this embodiment, the curvature radius R2 of the second curved portion 51b is preferably 1.5 times or more, more preferably 2.0 times or more, the curvature radius R3 of the third curved portion 51c. By setting the ratio between the radius of curvature R2 of the second curved portion 51b and the radius of curvature R3 of the third curved portion 51c within the above range, stress concentration on the first bridge portion 33 can be suppressed more effectively.

The projecting portion 59 has a first side surface 59a facing the magnetic pole center line L side and a second side surface 59b facing the inner magnet 36A side. The first side surface 59a extends linearly when viewed from the axial direction. The first side surface 59a is smoothly connected to the third curved portion 51c at the third boundary portion 55c. As a result, a corner is not provided at the boundary portion between the protrusion 59 and the first inner side surface 51 , and stress concentration in the rotor core 32 can be suppressed.

A second side surface 59b of the protrusion 59 extends linearly when viewed in the axial direction. The second side surface 59b faces the side surface of the inner magnet 36A. The second side 59b may contact the side of the inner magnet 36A. A boundary portion (fourth boundary portion 55d) between the third inner side surface 53 and the first curved portion 51a is arranged on an extension line of the second side surface 59b.

(outer magnet hole)
Next, the specific shape of the outer magnet hole 38B and its periphery will be described with reference to FIG.
The inner peripheral surface of the outer magnet hole 38B has a fifth inner surface 61, a sixth inner surface 62, a seventh inner surface 63, an eighth inner surface 64, and a pair of projections 68, 69. As shown in FIG.

The fifth inner side surface 61 is the inner side surface of one flux barrier portion 38e arranged on the magnetic pole center line L side. The fifth inner side surface 61 is located on the magnetic pole center line L side with respect to the outer magnet 36B accommodated in the outer magnet hole 38B.

The sixth inner surface 62 extends linearly along the circumferential direction. The sixth inner surface 62 faces radially outward. That is, the sixth inner side surface 62 is positioned radially inward with respect to the outer magnet 36B accommodated in the outer magnet hole 38B.

The seventh inner surface 63 extends linearly along the circumferential direction. The seventh inner surface 63 faces radially inward. That is, the seventh inner side surface 63 is located radially outside the outer magnet 36B housed in the outer magnet hole 38B. The seventh inner side surface 63 faces the sixth inner side surface 62 . The outer magnet 36B is arranged between the sixth inner surface 62 and the seventh inner surface 63 .

The eighth inner surface 64 is the inner surface of the flux barrier portion 38e located on the side opposite to the magnetic pole center line L side. The eighth inner surface 64 is located on the opposite side of the magnetic pole center line L with respect to the outer magnet 36B housed in the outer magnet hole 38B.

A pair of protrusions 68 and 69 are provided on the inner peripheral surface of the outer magnet hole 38B. The pair of protrusions 68 and 69 are arranged at both ends of the sixth inner surface 62 when viewed in the axial direction. Therefore, of the pair of protrusions 68 and 69, one protrusion 69 is located between the fifth inner surface 61 and the sixth inner surface 62, and the other protrusion 68 is positioned between the eighth inner surface 64 and the sixth inner surface. It is positioned between the inner surface 62 . The pair of protrusions 68 and 69 protrude from the sixth inner surface 62 side toward the seventh inner surface 63 side. That is, the pair of protrusions 68 and 69 protrude radially outward. The pair of protrusions 68 and 69 extend in a stripe shape along the axial direction. The outer magnet 36B is arranged between a pair of projections 68,69.

A fifth inner side surface 61 of the outer magnet hole 38B has a straight portion 61a extending parallel to the magnetic pole center line L at the end on the magnetic pole center line L side. Therefore, the second bridge portion 34 arranged between the pair of outer magnet holes 38B extends radially with a substantially uniform width dimension around the magnetic pole center line L. As shown in FIG. That is, according to the present embodiment, the inner peripheral surface of the outer magnet hole 38B has the straight portion 61a which is located on the magnetic pole center line L side with respect to the outer magnet 36B to be accommodated and extends linearly along the radial direction.

The second bridge portion 34 arranged between the pair of outer magnet holes 38B supports the radially outward force applied to the outer magnets 36B. On the other hand, the first bridge portion 33 supports the radially outward force applied not only to the outer magnet 36B but also to the inner magnet 36A. That is, the tensile stress applied to the second bridge portion 34 is smaller than the tensile stress applied to the first bridge portion 33 .

According to the present embodiment, the linear portion 61a is provided at the edge of the second bridge portion 34 to increase the strength of the second bridge portion 34 to the extent that it can sufficiently hold the outer magnet 36B even if stress is concentrated on the corner portion. can be secured. In addition, according to the present embodiment, by providing the straight portion 61a on the fifth inner side surface 61, compared with the case where the entire fifth inner side surface 61 is curved, the mold for forming the outer magnet hole 38B is reduced. Shape can be simplified. Thereby, the rotor core 32 can be manufactured at low cost.

In this specification, a pair of magnet holes arranged symmetrically in the circumferential direction with respect to the magnetic pole centerline L and having a curved first inner side surface 51 similar to the inner magnet hole 38A is referred to as a first magnet hole. call. That is, in the rotor core 32 of the present embodiment, only the inner magnet hole 38A of the inner magnet hole 38A and the outer magnet hole 38B is the first magnet hole. It should be noted that not only the inner magnet hole 38A but also the outer magnet hole 38B may be formed as first magnet holes in which the magnetic pole center line L side is curved in the same manner as the first inner surface 51. FIG. In this case, the strength of the second bridge portion 34 between the outer magnet holes 38B can be increased. That is, if at least one of the inner magnet hole 38A and the outer magnet hole 38B is the first magnet hole, it is possible to obtain a certain effect as described above.

<Modification>
Next, modifications that can be employed in the above-described embodiment will be described. In addition, in description of each modification described below, the same code|symbol is attached|subjected about the component of the same aspect as embodiment or modification already described, and the description is abbreviate|omitted.

FIG. 5 is a partial cross-sectional view of the rotor 130 of this modification.
The rotor 130 of this modified example differs from the above-described embodiment mainly in the configuration of a plurality of (three) magnets 136 forming one magnetic pole 103 and the configuration of the magnet holes 138 that accommodate these magnets 136. .

The rotor 130 of this modified example has a rotor core 132 and a plurality of magnets 136 as in the above-described embodiment. In this modification, three magnets 136 constitute one magnetic pole 103 . The rotor 130 has a plurality of magnetic poles 103 .

The plurality of magnets 136 includes inner magnets 36A and outer magnets 136B. In this modification, one magnetic pole 103 includes two inner magnets 36A and one outer magnet 136B. The inner magnet 36A has a configuration similar to that of the above embodiment.

A plurality of magnet holes 138 are provided in the rotor core 132 . Each magnet hole 138 axially penetrates the rotor core 132 . One magnet 136 is arranged in each magnet hole 138 .

The plurality of magnet holes 138 includes an inner magnet hole (first magnet hole) 38A and an outer magnet hole (second magnet hole) 138B. The number of inner magnet holes 38A in the embodiment is twice the number of outer magnet holes 138B. Three magnets 136 arranged in these three magnet holes 138 constitute one magnetic pole 103 . Three magnet holes 138 in which three magnets 136 forming one magnetic pole 103 are arranged are called a set S of magnet holes 138 .

Among the pair of inner magnet holes 38A of one set S, one on the one circumferential side (+θ side) of the magnetic pole center line L increases radially outward when viewed from the axial direction. ). Of the pair of inner magnet holes 38A of one set S, the other side (-.theta. θ side). That is, the circumferential distance between a pair of inner magnet holes 38A included in one set S gradually increases radially outward. On the other hand, the outer magnet hole 138B is arranged in the circumferential direction between the radially outer ends of the pair of inner magnet holes 38A. The outer magnet hole 138B is arranged radially outward of the pair of inner magnet holes 38A. The outer magnet hole 138B extends perpendicular to the magnetic pole centerline L. As shown in FIG.

The inner magnet hole 38A of this modified example has the same configuration as that of the above-described embodiment. That is, in the rotor core 132 of this modified example, the inner magnet hole 38A has the same first inner surface 51 as in the above-described embodiment. Therefore, according to this modified example, the strength of the first bridge portion 33 arranged between the inner magnet holes 38A can be increased, and the magnet 136 can be held stably.

A rotating electric machine to which the present invention is applied is not limited to a motor, and may be a generator. Applications of the rotating electric machine are not particularly limited. For example, the rotating electric machine may be mounted on a vehicle for an application other than driving the vehicle, or may be mounted on a device other than the vehicle. In addition, there are no particular restrictions on the orientation of the rotating electric machine when it is used.

Although the embodiments of the present invention and their modifications have been described above, each configuration and combination thereof in the embodiments and modifications are examples, and additions of configurations, Omissions, substitutions and other changes are possible. Moreover, the present invention is not limited by the embodiments.

3 Magnetic poles 10 Rotating electrical machine 30 Rotor 32 Rotor core 36 Magnets 38, 138 Magnet holes 38A Inner magnet hole (first magnet hole) 38B Outer magnet hole 138B Outer magnet Hole (second magnet hole) 40... Stator 51... First inner surface 51a... First curved portion 51b... Second curved portion 51c... Third curved portion 52... Second inner surface 58, 59 ... Protruding portion 61 ... Straight portion 61a, L ... Magnetic pole center line, J ... Central axis line

Claims (8)

a rotor core extending in the axial direction about the central axis and provided with a plurality of axially extending magnet holes;
a plurality of magnetic poles having a plurality of magnets arranged in the magnet holes,
The plurality of magnet holes includes a pair of first magnet holes extending in the radial direction and arranged symmetrically in the circumferential direction with respect to a magnetic pole center line passing through the center of the magnetic pole,
The inner peripheral surface of the magnet hole has a first inner surface located on the magnetic pole center line side with respect to the magnet to be accommodated,
The first inner surface is
a first curved portion curved in a concave shape;
a second curved portion connected to a radially inner end portion of the first curved portion and curved in a concave shape;
the radius of curvature of the first curved portion is greater than the radius of curvature of the second curved portion;
The first inner surface is closest to the magnetic pole centerline at the first curved portion,
rotor. The radius of curvature of the first curved portion is 1.5 times or more the radius of curvature of the second curved portion.
A rotor according to claim 1 . The inner peripheral surface of the first magnet hole is
a second inner surface that extends linearly along the circumferential direction and is positioned radially inward with respect to the accommodated magnet;
a protrusion positioned between the first inner surface and the second inner surface and protruding radially outward;
The first inner surface has a third curved portion that connects the second curved portion and the protrusion and curves in a concave shape,
the radius of curvature of the second curved portion is greater than the radius of curvature of the third curved portion;
The first inner surface is closest to the central axis in the second curved portion,
A rotor according to claim 1 or 2. The radius of curvature of the second curved portion is 1.5 times or more the radius of curvature of the third curved portion.
A rotor according to claim 3. The plurality of magnet holes are
a pair of inner magnet holes arranged symmetrically in the circumferential direction with respect to the magnetic pole center line;
a pair of outer magnet holes arranged radially outward of the inner magnet holes and arranged symmetrically in the circumferential direction with respect to the magnetic pole center line;
At least one of the inner magnet hole and the outer magnet hole is the first magnet hole,
A rotor according to any one of claims 1-4. Only the inner magnet hole is the first magnet hole,
The inner peripheral surface of the outer magnet hole has a linear portion located on the magnetic pole center line side with respect to the magnet to be housed and extending linearly along the radial direction,
A rotor according to claim 5 . The plurality of magnet holes includes a second magnet hole arranged radially outwardly of the pair of first magnet holes and extending orthogonally to the magnetic pole center line,
A rotor according to any one of claims 1-5. A rotor according to any one of claims 1 to 7;
a stator arranged radially outside the rotor;
rotating electric machine.

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