WO2023195258A1

WO2023195258A1 - Rotor, and rotating electric machine

Info

Publication number: WO2023195258A1
Application number: PCT/JP2023/006316
Authority: WO
Inventors: 真弘北野; 智哉上田; 嵩征原
Original assignee: ニデック株式会社
Priority date: 2022-04-08
Filing date: 2023-02-21
Publication date: 2023-10-12

Abstract

One aspect of a rotor of the present invention has a plurality of magnetic poles arranged along the circumferential direction, a rotor core extending in a columnar shape centered on a central axis, and a plurality of magnets that are held in a magnet hole of the rotor core and form magnetic poles. A straight line passing through the center of the magnetic poles when seen axially is a d-axis. An outer circumferential surface of the rotor core, which faces radially outward, has a plurality of outer end portions located on the d-axis of the respective magnetic poles, and a plurality of retract portions, each of which is located between the outer end portions in the circumferential direction, and offset to a radially inner side relative to the outer end portions.

Description

Rotor and rotating electric machine

The present invention relates to a rotor and a rotating electric machine.

This application is based on Japanese Patent Application No. 2022-064651 filed on April 8, 2022. This application claims priority over that application. The entire contents are incorporated into this application by reference.

Rotating electric machines can suppress vibration and noise by reducing cogging torque. BACKGROUND ART Conventional rotating electric machines reduce cogging torque by providing step skew in a rotor and a stator, as described in Patent Document 1, for example.

Japanese Publication No. 2004-159492

There is a problem that providing a skew increases the number of manufacturing steps for the rotating electric machine and reduces productivity. For this reason, there are expectations for the development of rotors and rotating electric machines that can reduce cogging torque without providing skew.

One of the objects of the present invention is to provide a rotor and a rotating electrical machine that can reduce cogging torque without providing skew.

One aspect of the rotor of the present invention is a rotor having a plurality of magnetic poles arranged along the circumferential direction, the rotor core extending in a columnar shape around a central axis, and the rotor core being held in a magnet hole of the rotor core and forming the magnetic poles. It has a plurality of magnets. A straight line passing through the center of the magnetic pole when viewed from the axial direction is the d-axis. The outer circumferential surface of the rotor core facing outward in the radial direction includes a plurality of outer end portions located on the d-axis of each of the magnetic poles, and a plurality of outer end portions located between the outer end portions in the circumferential direction and further than the outer end portions. A plurality of retraction portions are provided which are offset inward in the radial direction.

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

According to one aspect of the present invention, it is possible to provide a rotor and a rotating electrical machine that can reduce cogging torque without providing skew.

FIG. 1 is a schematic cross-sectional view of a rotating electrical machine according to an embodiment. FIG. 2 is a cross-sectional view of a rotating electric machine according to an embodiment. FIG. 3 is a partial cross-sectional view of the rotor of one embodiment. FIG. 4 is a graph showing simulation results of cogging torque when the first angle is changed in one embodiment. FIG. 5 is a graph showing simulation results of cogging torque in the example and the comparative example.

In each figure, the central axis J is shown as appropriate. The central axis J is a virtual line passing through the center of the rotating electrical machine in the following embodiments. The Z axis shown as appropriate 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 centered on the central axis J is simply referred to as the "radial direction." The circumferential direction centered on is simply called the "circumferential direction."

The arrow θ shown in the drawings indicates the circumferential direction. In the following explanation, the side that moves counterclockwise around the central axis J when viewed from the axial direction, that is, the side that the arrow θ points to (+θ side) will be referred to as "one side in the circumferential direction," and the side that moves clockwise, In other words, the opposite side (-θ side) to the side toward which the arrow θ is directed is called "the other side in the circumferential direction."

(rotating electrical machine)
FIG. 1 is a schematic cross-sectional view of the rotating electrical machine 10 along the central axis J. FIG. 2 is a cross-sectional view of the rotating electrical machine 10 along a plane perpendicular to the central axis J. Note that in FIG. 2, illustration of the housing 9 is omitted.

As shown in FIG. 1, the rotating electrical machine 10 of this embodiment is an inner rotor type rotating electrical machine. 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. As shown in FIG. 2, the rotating electric machine of this embodiment is an inner rotor type motor with 8 poles and 48 slots. Further, in this embodiment, the rotating electric machine 10 is a three-phase AC motor.

(stator)
As shown in FIG. 1, the stator 40 faces the rotor 30 with a gap therebetween. Stator 40 is arranged radially outside of rotor 30. Stator 40 includes a stator core 41, an insulator 42a, and a plurality of coils 42. Stator core 41 has an annular core back 41a and a plurality of teeth 41b that protrude radially inward from core back 41a. The plurality of coils 42 are respectively 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 includes a shaft 31, a rotor core 32, and a plurality of magnets 36. The shaft 31 has a cylindrical shape that extends in the axial direction centering on the central axis J.

As shown in FIG. 2, the rotor core 32 has an annular shape centered on the central axis J. The rotor 30 includes a plurality of magnetic poles 3 arranged along the circumferential direction. The plurality of magnetic poles 3 constitute N poles and S poles alternately in the circumferential direction. The rotor 30 of this embodiment includes eight magnetic poles 3. Therefore, the rotor 30 is assumed to have four d-axes and four q-axes. A straight line passing through the center of the magnetic pole 3 when looking at the rotor 30 from the axial direction is the d-axis Ld. Further, when the rotor 30 is viewed from the axial direction, the bisector of the d-axes Ld adjacent to each other in the circumferential direction is the q-axis Lq. All d-axes Ld and q-axes Lq pass through the central axis J.

The magnetic pole 3 is composed of a plurality of magnets 36. In this embodiment, one magnetic pole 3 includes three magnets 36. The rotor 30 of this embodiment has 24 magnets 36. The three magnets 36 of one magnetic pole 3 are arranged symmetrically about the d-axis Ld.

(rotor core)
The rotor core 32 extends in the axial direction centering on the central axis J in a columnar shape. The rotor core 32 has a central hole 32a that passes through the rotor core 32 in the axial direction, and a plurality of lightening holes 32h. The central hole 32a has a substantially circular shape centered on the central axis J. The shaft 31 (see FIG. 1) is passed through the central hole 32a in the axial direction. The lightening holes 32h are arranged along the circumferential direction. The lightening hole 32h is arranged on the q-axis Lq. Although the lightening hole 32h of this embodiment has a substantially triangular shape when viewed from the axial direction, the shape of the lightening hole 32h is not limited to this embodiment.

The rotor core 32 is made of magnetic material. Although not particularly illustrated, 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 in the axial direction. The lamination has a substantially annular plate shape centered on the central axis J. The lamination is, for example, an electrical steel sheet.

A plurality of magnet holes 38 are provided in the rotor core 32. When viewed from the axial direction, the magnet holes 38 are arranged radially outward of the center hole 32a and spaced apart in the circumferential direction. Each magnet hole 38 passes through the rotor core 32 in the axial direction. The magnet hole 38 has a uniform shape and extends in the axial direction. 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, caulking, and adhesive. That is, the magnet 36 is held in the magnet hole 38 of the rotor core 32.

FIG. 3 is a partial cross-sectional view of the rotor 30 around the magnetic poles 3.
The plurality of magnet holes 38 include a first magnet hole 38A and a second magnet hole 38B. The first magnet hole 38A is arranged radially outward of the second magnet hole 38B. The pair of second magnet holes 38B are arranged symmetrically in the circumferential direction with respect to the d-axis Ld.

The number of second magnet holes 38B in this embodiment is twice the number of first magnet holes 38A. A total of three magnets 36, one placed in each of these three magnet holes 38, constitute one magnetic pole 3. The three magnet holes 38 in which the three magnets 36 constituting one magnetic pole 3 are arranged are called a group S of magnet holes 38.

Of the pair of second magnet holes 38B of one set S, one of the circumferential one side (+θ side) of the d-axis Ld becomes smaller as it goes radially outward as seen from the axial direction. ). Of the pair of second magnet holes 38B of one set S, the other one on the other side in the circumferential direction (-θ side) of the d-axis Ld becomes smaller on the other side in the circumferential direction (-θ side) as it goes radially outward when viewed from the axial direction. θ side). That is, the distance between the pair of second magnet holes 38B included in one set S in the circumferential direction gradually increases toward the outside in the radial direction. On the other hand, the first magnet hole 38A is arranged in the circumferential direction between each radially outer end 36h of the pair of second magnet holes 38B. The first magnet hole 38A is arranged radially outward with respect to the pair of second magnet holes 38B. The first magnet hole 38A extends orthogonally to the d-axis Ld.

A pair of first flux barrier parts 38c are provided at both ends of the first magnet hole 38A. The pair of first flux barrier parts 38c are arranged at both ends of the magnet 36 accommodated in the first magnet hole 38A. A second flux barrier portion 38d is provided at the radially inner end of the second magnet hole 38B. A third flux barrier portion 38e is provided at the radially outer end of the second magnet hole 38B. The second flux barrier section 38d and the third flux barrier section 38e are arranged at both ends of the magnet 36 accommodated in the second magnet hole 38B.

In this specification, the "flux barrier section" is a section that can suppress the flow of magnetic flux. The configuration of each of the

flux barrier parts

38c, 38d, and 38e is not particularly limited as long as it can suppress the flow of magnetic flux, and may include a gap or a non-magnetic part such as a resin part. In this embodiment, the

flux barrier portions

38c, 38d, and 38e are void portions formed by holes that penetrate the rotor core 32 in the axial direction.

One magnet 36 is placed 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.

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. In the following description, when the magnet 36 is viewed from the axial direction, the direction along the short side of the magnet 36 will be referred to as the thickness direction, and the direction along the long side will be referred to as the longitudinal direction. The magnet 36 of this embodiment has a thickness direction as a magnetization direction.

The magnet 36 extends, for example, from one axial end of the rotor core 32 to the other axial end. Note that 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). Furthermore, the shape of the magnet 36 is not limited to that described above.

In the following description, the magnet 36 disposed in the first magnet hole 38A will be referred to as a first magnet 36A. Similarly, the magnet 36 disposed in the second magnet hole 38B is referred to as a second magnet 36B. The magnetic pole 3 includes one first magnet 36A and a pair of second magnets 36B. The first magnet 36A and the second magnet 36B of this embodiment both have a rectangular shape when viewed from the axial direction, but have different dimensions in the thickness direction and the longitudinal direction. However, the first magnet 36A and the second magnet 36B may have the same shape.

One first magnet 36A included in one magnetic pole 3 is arranged on the d-axis Ld. The first magnet 36A makes the thickness direction coincide with the radial direction. Therefore, the first magnet 36A has its magnetization direction in the direction in which the d-axis Ld extends. Further, the center position of the first magnet 36A in the longitudinal direction is located on the d-axis Ld.

A pair of second magnets 36B included in one magnetic pole 3 are arranged symmetrically in the circumferential direction with respect to the d-axis Ld. The pair of second magnets 36B are spaced apart from each other toward the outside in the radial direction. The second magnet 36B has its thickness direction directed toward the first magnet 36A. The magnetization direction of the second magnet 36B points toward the first magnet 36A.

One first magnet 36A and a pair of second magnets 36B constituting one magnetic pole 3 each have the same polarity radially outward. For example, if the radially outward facing surface of the first magnet 36A is a north pole, the radially outward facing surface of the second magnet 36B is also a north pole.

(Outer peripheral surface of rotor core)
Rotor core 32 has an outer circumferential surface 35. The outer circumferential surface 35 is a surface facing outward in the radial direction. The outer peripheral surface 35 is provided with a plurality of outer end portions 35c and a plurality of retraction portions 35d.

The outer end portion 35c is located on the d-axis Ld of each magnetic pole 3. The outer end portion 35c extends in an arc shape when viewed from the axial direction. The plurality of outer end portions 35c are arranged on a virtual circle CV centered on the central axis J. The outer circumferential surface 35 of the rotor core 32 is not provided with a portion that protrudes radially outward from the virtual circle CV. That is, the outer end portion 35c constitutes the outer diameter of the rotor core 32. The outer end portion 35c is a fixed area provided on both sides of the d-axis Ld in the circumferential direction with the d-axis Ld as the center. The outer end portion 35c is provided for each magnetic pole 3. Therefore, the rotor core 32 of this embodiment is provided with eight outer end portions 35c, the same number as the magnetic poles 3.

The retraction portion 35d is offset radially inward from the outer end portion 35c. Therefore, the outer end 35c is located radially inward than the virtual circle CV passing through the outer end 35c. The retraction portion 35d is located between a pair of outer end portions 35c adjacent to each other in the circumferential direction. The retraction portion 35d is located on the q-axis Lq. The rotor core 32 is provided with the same number (eight) of retraction portions 35d as the outer end portions 35c.

According to this embodiment, the outer end portion 35c located on the d-axis Ld constitutes the outermost diameter of the rotor core 32. Therefore, the rotor 30 is closest to the stator 40 in the radial direction at the outer end 35c. On the other hand, the outer diameter of the retracted portion 35d is smaller than the outer diameter of the outer end portion 35c. Therefore, the radial gap between the rotor 30 and the stator 40 is larger on the radially outer side of the retracted portion 35d than on the radially outer side of the outer end portion 35c. According to this embodiment, the rotor 30 can make the attractive force and repulsive force received from the magnetic field of the stator 40 at the retracting portion 35d relatively smaller than the attractive force and repulsive force received at the outer end portion 35c.

As shown in FIG. 2, the rotating electric machine 10 of this embodiment has a sufficiently large number of poles relative to the number of slots, and one magnetic pole 3 faces a plurality of teeth 41b. The force that one magnetic pole 3 receives from the stator 40 on the d-axis Ld and the force that it receives from the stator 40 at the end in the circumferential direction are different in phase and cause cogging torque.

The outer circumferential surface 35 of the rotor 30 of this embodiment is provided with a retraction portion 35d between the d-axes Ld arranged in the circumferential direction, thereby reducing the force received from the stator 40 in areas remote from the d-axis Ld on both sides in the circumferential direction. Therefore, the cogging torque of the rotating electric machine 10 can be suppressed.

As shown in FIG. 3, the retraction portion 35d has a first flat surface 35a and a second flat surface 35b as flat surfaces. That is, the retraction portion 35d has

flat surfaces

35a and 35b. The first flat surface 35a and the second flat surface 35b are flat surfaces each facing outward in the radial direction and extending along the axial direction. The first flat surface 35a is located between the outer end 35c and the second flat surface 35b in the circumferential direction. On the other hand, the second flat surface 35b is located between the first flat surfaces 35a in the circumferential direction. Therefore, one retraction portion 35d is provided with one second flat surface 35b and a pair of first flat surfaces 35a located on both sides of the second flat surface 35b in the circumferential direction.

The first flat surface 35a is orthogonal to a virtual orthogonal line La passing through the central axis J when viewed from the axial direction. Therefore, the distance between the first flat surface 35a and the virtual circle CV is greatest on the orthogonal line La. Similarly, the distance between the first flat surface 35a and the stator 40 is also greatest on the orthogonal line La. The first flat surface 35a is located on the radially outer side of the radially outer end 36k of the first magnet 36A. Note that the radially outer end 36k of the first magnet 36A means a portion of the first magnet 36A that is disposed farthest from the center axis J in the radial direction. In the first magnet 36A of this embodiment, the radial position is furthest away from the central axis J at the longitudinal end 36k. Therefore, the first flat surface 35a is located on the radially outer side of the longitudinal end portion 36k of the first magnet 36A.

The first flat surface 35a is located on the radially outer side of the first flux barrier section 38c. The first flux barrier portion 38c faces the end portion 36k of the first magnet 36A in the longitudinal direction of the first magnet 36A. The magnetic flux within the rotor core 32 tends to concentrate between the first flux barrier portion 38c and the outer peripheral surface 35. The first flat surface 35a is located on the radially outer side of the portion of the rotor core 32 where the magnetic flux density is high.

The second flat surface 35b is arranged on the q-axis Lq. The second flat surface 35b is a surface perpendicular to the q-axis. That is, the q-axis Lq is a line orthogonal to the second flat surface 35b. Moreover, the second flat surface 35b is perpendicular to a virtual orthogonal line (q-axis Lq) passing through the central axis when viewed from the axial direction. The distance between the second flat surface 35b and the virtual circle CV is greatest on the q-axis Lq. Similarly, in the second flat surface 35b, the distance between the second flat surface 35b and the stator 40 is also the largest on the q-axis Lq. The second flat surface 35b is located on the radially outer side of the radially outer end 36h of the second magnet 36B.

The second flat surface 35b is located on the radially outer side of the third flux barrier portion 38e. The third flux barrier portion 38e faces the end portion 36h of the second magnet 36B in the longitudinal direction of the second magnet 36B. The magnetic flux within the rotor core 32 tends to concentrate between the third flux barrier portion 38e and the outer peripheral surface 35. The second flat surface 35b is located on the radially outer side of the portion of the rotor core 32 where the magnetic flux density is high.

According to the present embodiment, the retraction portion 35d has a first flat surface 35a and a second flat surface 35b, which are perpendicular to virtual orthogonal lines La and Lq passing through the central axis when viewed from the axial direction. . Therefore, the dimensions of the retracted portion 35d can be measured on a flat surface, and the dimensions can be easily controlled in the manufacturing process of the rotor core 32.

According to this embodiment, the first flat surface 35a is located on the radially outer side of the radially outer end 36k of the first magnet 36A, and the second flat surface 35b is located on the radially outer side of the second magnet 36B. It is located on the radially outer side of the end portion 36h. The magnetic flux within the rotor core 32 tends to increase on the radially outer side of the

ends

36k and 36h of the magnet 36. Therefore, the attractive force and repulsive force applied from the stator 40 to the radially outer sides of the

end portions

36k and 36h of the magnet 36 change with large amplitude depending on the rotation angle, and become a factor in increasing the cogging torque. By providing

flat surfaces

35a and 35b on the radially outer sides of the

ends

36k and 36h of the magnet 36, the attractive and repulsive forces generated at the

ends

36k and 36h of the magnet 36 can be suppressed, and the cogging torque of the rotating electric machine 10 can be reduced. Can be reduced.

In particular, in this embodiment, the rotor core 32 is provided with

flux barrier parts

38c and 38e that face the

ends

36k and 36h of the magnet 36. The magnetic flux density within the rotor core 32 tends to be high on the radially outer side of the

flux barrier portions

38c and 38e. In this embodiment, the first flat surface 35a and the second flat surface 35b are located on the radially outer side of the flux barrier parts 38c and 35e, so that the stator 40 It is possible to suppress the magnetic flux density between the two and reduce the cogging torque.

According to this embodiment, the retraction portion 35d has a first flat surface 35a located on the radially outer side of the radially outer end 36k of the first magnet 36A. The first flat surface 35a reduces the attractive force and repulsive force acting on the radially outer region of the end portion 36k of the first magnet 36A. The first flat surface 35a can reduce cogging torque caused by the first magnet 36A.

Note that the effect of suppressing cogging torque by the first flat surface 35a can be obtained with the rotor 30 having the first magnet 36A. This effect can also be obtained, for example, in the rotor 30 that has only the first magnet 36A and does not have the second magnet 36B.

Here, the angle formed by the orthogonal line La passing through the central axis J and orthogonal to the first flat surface 35a and the d-axis Ld is defined as a first angle α. Further, the angle formed by the d-axis Ld and the q-axis Lq is defined as a second angle φ. Since the rotor 30 of this embodiment has eight poles, the second angle φ is 22.5°. The first angle α is preferably 49% or more and 50.5% or less with respect to the second angle φ (49%≦α/φ≦50.5%).

FIG. 4 is a graph showing the simulation results of cogging torque when the first angle α is changed in this embodiment. As shown in FIG. 4, the cogging torque changes by changing the first angle α. According to FIG. 4, the cogging torque can be reduced most when the first angle α is approximately 49.5% of the second angle φ. More specifically, cogging torque can be effectively suppressed by setting the first angle α to 49% or more and 50.5% or less of the second angle φ.

In the present embodiment, the retraction portion 35d has a second flat surface 35b located on the radially outer side of the radially outer end of the second magnet 36B. The second flat surface 35b reduces the attractive force and repulsive force acting on the radially outer region of the end portion 36h of the second magnet 36B. The second flat surface 35b can reduce cogging torque caused by the second magnet 36B.

Note that the effect of suppressing cogging torque by the second flat surface 35b can be obtained if the rotor 30 has a pair of second magnets 36B. This effect can also be obtained, for example, in the rotor 30 that has only the pair of second magnets 36B and does not have the first magnet 36A.

In this embodiment, the second flat surface 35b is perpendicular to the q-axis Lq. Therefore, the second flat surface 35b is spaced farthest from the stator 40 on the q-axis Lq. Since the q-axis Lq is located between the d-axes Ld, the function of the q-axis Lq is that the magnetic flux density is low. By making the second flat surface 35b orthogonal to the q-axis Lq, reduction in the average torque of the rotor 30 can be suppressed. That is, by setting the second flat surface 35b to the q-axis Lq, cogging torque can be suppressed while maintaining the average torque.

Furthermore, in this embodiment, the retraction portion 35d has the largest offset amount on the q-axis Lq. That is, the amount of offset of the second flat surface 35b is larger than the amount of offset of the first flat surface 35a. Here, the offset amount means the distance in the radial direction from the virtual circle CV. Even if the offset amount is increased near the q-axis Lq, it is easy to maintain the average torque. According to this embodiment, cogging torque can be suppressed while maintaining average torque.

FIG. 5 is a graph showing the simulation results of cogging torque of the example and the comparative example. The rotating electrical machine of the example is a rotating electrical machine having the same configuration as this embodiment. Moreover, the rotating electrical machine of the comparative example is a rotating electrical machine with a conventional structure. That is, in the rotating electric machine of the comparative example, the outer peripheral surface of the rotor core is circular when viewed from the axial direction. The outer circumferential surface of the rotor core of the comparative example is located on the virtual circle CV in FIG. 3 over the entire circumference. In FIG. 5, the horizontal axis is the rotation angle, and the vertical axis is the rotational torque of the rotor. As shown in FIG. 5, according to the rotating electrical machine of this embodiment (example), cogging torque can be reduced compared to the conventional structure (comparative example).

The rotating electric machine to which the present invention is applied is not limited to a motor, but may be a generator. The use of the rotating electric machine is not particularly limited. For example, the rotating electric machine may be mounted on a vehicle for purposes other than driving the vehicle, or may be mounted on equipment other than the vehicle. Moreover, the posture when the rotating electric machine is used is not particularly limited.

Note that the present technology can have the following configuration.
(1) A rotor having a plurality of magnetic poles arranged along the circumferential direction, including a rotor core extending in a columnar shape around a central axis, and a plurality of magnets held in magnet holes of the rotor core and forming the magnetic poles. A straight line passing through the center of the magnetic pole when viewed from the axial direction is the d-axis, and the outer peripheral surface of the rotor core facing outward in the radial direction has a plurality of outer end portions located on the d-axis of each of the magnetic poles. and a plurality of retraction portions located between the outer end portions in the circumferential direction and offset radially inward from the outer end portions.
(2) The rotor according to (1), wherein the retracting portion has a flat surface that is perpendicular to a virtual orthogonal line passing through the central axis when viewed from the axial direction.
(3) The rotor according to (2), wherein the flat surface is located on the radially outer side of the radially outer end of the magnet.
(4) The magnetic pole includes a first magnet that is arranged on the d-axis and whose magnetization direction is in the direction in which the d-axis extends, and the recessed portion includes a radially outer end of the first magnet as the flat surface. The rotor according to (3), wherein the rotor has a first flat surface located on a radially outer side of the rotor.
(5) The bisector of the d-axes adjacent to each other in the circumferential direction is the q-axis, and when viewed from the axial direction, the orthogonal line passing through the central axis and orthogonal to the first flat surface and the d-axis The rotor according to (4), wherein the angle formed by the d-axis and the q-axis is 49% or more and 50.5% or less with respect to the angle formed by the d-axis and the q-axis.
(6) The magnetic poles include a pair of second magnets arranged symmetrically in the circumferential direction with respect to the d-axis, and the pair of second magnets are spaced apart from each other toward the outside in the radial direction. , the retracting portion has a second flat surface located radially outward of the radially outer end of the second magnet as the flat surface, according to any one of (3) to (5). Rotor.
(7) The q-axis is the bisector between the d-axes adjacent to each other in the circumferential direction, and the second flat surface is perpendicular to the q-axis located on the bisector between the d-axes adjacent to the circumferential direction. , (6). (8) The rotor described in (1) to (7) is provided, and a stator disposed radially outward of the rotor.

The embodiments of the present invention and their modifications have been described above, but each configuration and combination thereof in the embodiments and modifications are merely examples, and additions of configurations and modifications may be made without departing from the spirit of the present invention. Omissions, substitutions and other changes are possible. Moreover, the present invention is not limited by the embodiments.

3... Magnetic pole, 10... Rotating electric machine, 30... Rotor, 32... Rotor core, 35... Outer peripheral surface, 35a... First flat surface (flat surface), 35b... Second flat surface (flat surface), 35c... Outer end part, 35d... Retraction part, 36... Magnet, 36h, 36k... End, 36A... First magnet, 36B... Second magnet, 38... Magnet hole, 40... Stator, 48... Pole, J... Central axis line, La... Orthogonal line , Ld...d axis, Lq...q axis (orthogonal line)

Claims

A rotor having a plurality of magnetic poles arranged along the circumferential direction,
A rotor core that extends in a columnar shape around a central axis,
a plurality of magnets held in the magnet holes of the rotor core and forming the magnetic poles;
A straight line passing through the center of the magnetic pole when viewed from the axial direction is the d-axis,
The outer circumferential surface of the rotor core facing outward in the radial direction includes:
a plurality of outer ends located on the d-axis of each of the magnetic poles;
a plurality of retraction portions located between the outer ends in the circumferential direction and offset radially inward from the outer ends;
Rotor.
The retraction portion has a flat surface that is perpendicular to a virtual orthogonal line passing through the central axis when viewed from the axial direction.
A rotor according to claim 1.
The flat surface is located on the radially outer side of the radially outer end of the magnet.
A rotor according to claim 2.
The magnetic pole includes a first magnet that is arranged on the d-axis and whose magnetization direction is the direction in which the d-axis extends,
The retraction portion has a first flat surface located radially outward of a radially outer end of the first magnet as the flat surface.
A rotor according to claim 3.
The bisector of the d-axes adjacent to each other in the circumferential direction is the q-axis,
Viewed from the axial direction, the angle formed by the orthogonal line passing through the central axis and orthogonal to the first flat surface and the d-axis is 49% of the angle formed by the d-axis and the q-axis. It is not less than 50.5%,
A rotor according to claim 4.
The magnetic poles include a pair of second magnets disposed line-symmetrically in the circumferential direction with respect to the d-axis,
The pair of second magnets are arranged to be spaced apart from each other as they go radially outward, and the recessed portion is a second magnet located radially outward of a radially outer end of the second magnet as the flat surface. having a flat surface,
The rotor according to any one of claims 3 to 5.
The bisector of the d-axes adjacent to each other in the circumferential direction is the q-axis,
The second flat surface is orthogonal to the q-axis located on the bisector of the d-axes adjacent to each other in the circumferential direction.
A rotor according to claim 6.
A rotor according to any one of claims 1 to 5,
A rotating electrical machine, comprising: a stator disposed radially outside the rotor.