WO2023171530A1 - Rotor core, rotor, and rotating electrical machine - Google Patents

Abstract

This rotor core can rotate about a central axis and comprises: a plurality of magnetic pole parts disposed at intervals in the circumferential direction; and a plurality of magnetic pole intermediate parts respectively positioned between the magnetic pole parts adjacent in the circumferential direction. Each of the plurality of magnetic pole intermediate parts has a through-hole group including a plurality of through-holes disposed at intervals in a radial direction. Each through-hole has an outer end positioned on the radial-direction outer edge of the rotor core, and the outer ends are respectively disposed on the plurality of magnetic pole intermediate parts in a first region and a second region disposed sandwiching the circumferential-direction center of the magnetic pole intermediate parts. The number of outer ends disposed in the second region is less than the number of outer ends disposed in the first region.

Description

Rotor core, rotor and rotating electrical machinery

The present invention relates to a rotor core, a rotor, and a rotating electrical machine.

This application is based on Japanese Patent Application No. 2022-035304 filed on March 8, 2022. This application claims priority over that application. The entire contents are incorporated into this application by reference.

A rotating electric machine is known that has a rotor that includes a rotor core and a hole provided in the rotor core. For example, the rotor core of Patent Document 1 has a plurality of holes serving as flux barriers that are convex toward the inside in the radial direction when viewed in the axial direction of the rotor core. The plurality of holes have an asymmetric shape with respect to the center axis in the circumferential direction of two adjacent magnetic pole parts.

Chinese Patent No. 107872136

The plurality of holes in Patent Document 1 include holes that are asymmetrical with respect to the center axis in the circumferential direction of two adjacent magnetic pole parts in order to reduce torque ripple. In some cases, the performance of the rotating electrical machine at startup and the efficiency during normal rotation when the rotating electrical machine reaches its rated speed cannot be sufficiently improved.

In view of the above circumstances, an object of the present invention is to provide a rotor core, a rotor, and a rotating electrical machine having a structure that can improve the torque at startup while suitably maintaining the flow of magnetic flux during normal rotation in the rotating electrical machine. Make it one.

One aspect of the rotor core of the present invention is a rotor core that is rotatable around a central axis, and includes a plurality of magnetic pole portions arranged at intervals in the circumferential direction, and a space between the magnetic pole portions that are adjacent to each other in the circumferential direction. A plurality of magnetic pole intermediate portions are respectively located. Each of the plurality of magnetic pole intermediate portions has a through hole group including a plurality of through holes arranged at intervals in the radial direction. Each of the through holes has an outer end located at a radially outer edge of the rotor core, and in each of the plurality of magnetic pole intermediate portions, a first region is disposed across the circumferential center of the magnetic pole intermediate portion. The outer end portions are arranged in the and second regions, respectively. The number of the outer ends arranged in the second region is smaller than the number of the outer ends arranged in the first region.

One aspect of the rotor of the present invention includes the rotor core described above and a conductor located within the through hole.

One aspect of the rotating electric machine of the present invention includes the above-mentioned rotor and a stator located on the radially outer side of the rotor.

According to one aspect of the present invention, it is possible to provide a rotor core, a rotor, and a rotating electrical machine having a structure that can improve the torque at startup while suitably maintaining the flow of magnetic flux during normal rotation in the rotating electrical machine.

FIG. 1 is a sectional view showing a schematic diagram of a rotating electric machine according to this embodiment. FIG. 2 is a sectional view showing the rotor of this embodiment, and is a sectional view taken along line II-II in FIG. FIG. 3 is a partially enlarged view of the rotor core of this embodiment. FIG. 4 is a partial sectional view showing a modification of the rotor core of this embodiment. FIG. 5 is a sectional view showing another modification of the rotor core of this embodiment. FIG. 6 is a sectional view showing another modification of the rotor core of this embodiment. FIG. 7 is a partially enlarged view showing the rotor core of Comparative Example 1. FIG. 8 is a partially enlarged view showing the rotor core of Comparative Example 2.

The Z-axis direction appropriately shown in each figure is an up-down direction in which the positive side is the "upper side" and the negative side is the "lower side." A central axis J shown as appropriate in each figure is an imaginary line that is parallel to the Z-axis direction and extends in the vertical direction. In the following description, the axial direction of the central axis J, that is, the direction parallel to the vertical direction, 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." When viewed from above in the axial direction, the direction of clockwise movement in the circumferential direction is called the +θ side, and the direction of movement counterclockwise is called the -θ side.

Note that the terms "vertical direction, upper side," and "lower side" are simply names used to explain the arrangement of each part, and the actual arrangement may be other than those indicated by these names. There may be.

The rotating electrical machine 1 of this embodiment shown in FIG. 1 is an inner rotor type motor. As shown in FIG. 1, the rotating electric machine 1 of this embodiment includes a housing 2, a rotor 10, a stator 3, a bearing holder 4, and bearings 5a and 5b. The housing 2 houses therein a rotor 10, a stator 3, a bearing holder 4, and bearings 5a and 5b. The bottom of the housing 2 holds a bearing 5b. The bearing holder 4 holds a bearing 5a. The bearings 5a and 5b are, for example, ball bearings.

The stator 3 is located on the outside of the rotor 10 in the radial direction. As shown in FIG. 1, the stator 3 includes a stator core 3a, an insulator 3d, and a plurality of coils 3e. Stator core 3a has a core back 3b and a plurality of teeth 3c. The core back 3b has an annular shape centered on the central axis J. The plurality of teeth 3c extend radially inward from the core back 3b. The plurality of teeth 3c are arranged at equal intervals all around the circumferential direction. The plurality of coils 3e are attached to the stator core 3a via an insulator 3d.

The rotor 10 is rotatable around the central axis J. As shown in FIGS. 1 and 2, the rotor 10 includes a shaft 11, a rotor core 20, a conductor 40, and an annular conductive portion 50. The shaft 11 has a cylindrical shape that extends in the axial direction centering on the central axis J. As shown in FIG. 1, the shaft 11 is rotatably supported around a central axis J by bearings 5a and 5b.

Rotor core 20 is a magnetic material. The material of the rotor core 20 is, for example, silicon steel, which has higher magnetic permeability and lower electrical conductivity than an alloy of iron and carbon. The rotor core 20 is fixed to the outer peripheral surface of the shaft 11. The rotor core 20 has a center through hole 20a that passes through the rotor core 20 in the axial direction. As shown in FIG. 2, the center through hole 20a has a circular shape centered on the center axis J when viewed in the axial direction. The shaft 11 is passed through the center through hole 20a. The shaft 11 is fixed within the center through hole 20a by, for example, press fitting. Although not shown, the rotor core 20 is configured by, for example, a plurality of electromagnetic steel sheets laminated in the axial direction.
The annular conductive portions 50 are arranged at both ends of the rotor core 20 in the axial direction. The annular conductive portion 50 has an annular shape centered on the central axis J. The outer diameter of the annular conductive portion 50 is equivalent to the outer diameter of the rotor core 20, and the inner diameter of the annular conductive portion 50 is larger than the inner diameter of the center through hole 20a of the rotor core 20. The material constituting the annular conductive portion 50 is a material with high electrical conductivity. Examples of the material constituting the annular conductive portion 50 include aluminum, copper, and an alloy of aluminum and copper.

The rotor core 20 has a plurality of through holes 30. In this embodiment, each through hole 30 is formed by a hole provided in the rotor core 20. For example, the through hole 30 passes through the rotor core 20 in the axial direction. Each through hole 30 extends along a plane perpendicular to the axial direction, and has a shape that is convex radially inward when viewed in the axial direction. The rotor core 20 is provided with a plurality of sets each including two or more through holes 30 . One set of through holes 30 is also referred to as a through hole group 130. Each through-hole group 130 includes a plurality of through-holes 30.

The rotor core 20 provided with the through holes 30 in this manner becomes a rotor core of a synchronous reluctance motor having a magnetic salient pole structure. More specifically, since the through-holes 30 through which magnetic flux is difficult to pass act as flux barriers for the rotor 10, when viewed from the axial direction, the two adjacent through-hole groups 130 are in the direction of salient poles through which magnetic flux can easily pass. A direction in which magnetic flux is difficult to pass is provided at the center in the circumferential direction of each through-hole group 130. In the following description, the salient pole direction through which the magnetic flux easily passes is referred to as the "d-axis direction", and the direction through which the magnetic flux is difficult to pass is referred to as the "q-axis direction". Since the rotor core 20 has magnetic anisotropy in the q-axis direction and the d-axis direction, reluctance torque is generated when a magnetic field is generated by the stator 3, making it possible to rotate the rotor 10.

Further, the d-axis direction is a radial direction passing through the circumferential center of the magnetic pole portions P of the rotor core 20, and the q-axis direction is a radial direction passing through the circumferential center between circumferentially adjacent magnetic pole portions P. The portion located between circumferentially adjacent magnetic pole portions P will hereinafter be referred to as a magnetic pole intermediate portion M. The q-axis passes through the middle part M of the magnetic pole.
In this way, the rotor 10 is provided with a plurality of magnetic pole parts P provided along the circumferential direction and a plurality of magnetic pole intermediate parts M located between circumferentially adjacent magnetic pole parts P. . Each of the magnetic pole intermediate portions M has a through hole group 130.

In this embodiment, a conductor 40 is disposed within the through hole 30 . Among the plurality of through holes 30, the insides of all the through holes 30 are filled with a conductor 40. The material constituting the conductor 40 has high electrical conductivity. The material constituting the conductor 40 is the same as the material constituting the annular conductive portion 50, and examples thereof include aluminum, copper, and an alloy of aluminum and copper. The material constituting the conductor 40 is a non-ferromagnetic metal so as not to affect the magnetic salient pole structure constituted by the through hole 30.
The conductor 40 disposed in each through hole 30 is electrically connected to an annular conductive portion 50, respectively. Therefore, the conductors 40 in each through hole 30 are electrically connected to each other via the annular conductive part 50, and the annular conductor 50 electrically shorts the conductors 40 in each through hole 30 to each other. .
The conductor 40 in the through hole 30 is made by heating the metal that will become the conductor 40 and pouring it into the through hole 30.
In this embodiment, the conductor 40 and the annular conductive portion 50 are part of the same single member. For example, molds for the annular conductive portion 50 are placed on both sides of the rotor core 20 in the axial direction, and the conductor 40 and the metal that will become the annular conductive portion 50 are heated and poured into the through hole 30 and the mold. And an annular conductive part 50 is made.
Note that the conductor 40 and the annular conductive portion 50 may be separate members or may be made of different constituent materials.

When the conductor 40 is placed in the through hole 30 of the synchronous reluctance motor, the conductor will be placed in a rotating magnetic field. Therefore, when the magnetic field generated by the stator 3 rotates, an induced current flows through the conductor 40 due to electromagnetic induction, and the Lorentz force of the induced current allows the rotor 10 to generate rotational force. In particular, since torque due to Lorentz force can be obtained when the stationary rotor 10 starts rotating, performance at startup can be improved. A synchronous reluctance motor with improved startup characteristics in this way is also called a DOL SynRM (Direct-On-Line Synchronous Reluctance Motor).

Here, in the rotor 10 having a magnetic salient pole structure, since the conductors 40 are not arranged in the magnetic pole part P, the amount of the conductors 40 arranged in the circumferential direction is not equal. For this reason, compared to conventional induction motors, the Lorentz force generated during startup is small, resulting in poor performance during startup.

Therefore, in a rotor core 20 having a plurality of through holes 30 having an asymmetric shape when the q-axis is an axis of symmetry, the inventors have developed It has been found that by increasing the cross-sectional area of the conductor 40 in the through hole 30 and increasing the arrangement area of the conductor 40 in the through hole 30, a larger torque due to the Lorentz force can be obtained when starting the stationary rotor 10. Furthermore, it has been found that with such a rotor core 20, efficiency can also be suitably ensured during normal rotation when the rotating electric machine 1 rotates at the rated speed.

Hereinafter, the configuration of the through hole 30 of the rotor core 20 of this embodiment will be described in more detail using FIGS. 2 and 3.

(Through hole 30)
The rotor core 20 of this embodiment includes four sets of through holes 30, each including an outermost through hole 31, a first intermediate through hole 32, a second intermediate through hole 33, and an innermost through hole 34. It has a group of through holes 130. The outermost through hole 31, the first intermediate through hole 32, the second intermediate through hole 33, and the innermost through hole 34 are arranged in this order from the radially outer side to the radially inner side. In the through-hole group 130 of the present embodiment, among the plurality of through-holes 30, the through-hole located most radially outward is the outermost through-hole 31, and the through-hole located most radially inward is the innermost through-hole 31. It is 34.

In this embodiment, four through holes 30 are arranged in one through hole group 130. The number of through holes 30 in one set of through hole groups 130 is not limited to four, as long as two or more through holes 30 including the outermost through hole 31 and the innermost through hole 34 are arranged. . That is, the intermediate through hole between the outermost through hole 31 and the innermost through hole 34 may not be arranged. The number of through holes 30 may be changed as appropriate depending on the size of rotor core 20.
Hereinafter, when any one of the outermost through hole 31, the first intermediate through hole 32, the second intermediate through hole 33, and the innermost through hole 34 is referred to, it will also simply be referred to as the through hole 30.

The four through-hole groups 130 are arranged at equal intervals along the circumferential direction of the rotor core 20. Each set of through-hole groups 130 has the same configuration except that each set is arranged in a position rotated by 90° in the circumferential direction. In the following description of each through-hole 30, the through-hole 30 included in one representative group among the four through-hole groups 130 will be described.

The outermost through hole 31, the first intermediate through hole 32, the second intermediate through hole 33, and the innermost through hole 34 included in the through hole group 130 are not in contact with each other and are separated from each other in the radial direction. It is well located. In the rotor core 20, a radially outer region of the outermost through hole 31, a region between two radially adjacent through holes 30, and a radially inner region of the through hole group 130 are This becomes a magnetic path MP through which the magnetic flux generated by 3 flows.

The through hole 30 has an arcuate shape that is convex radially inward when viewed in the axial direction. The arc radius of the first intermediate through hole 32 is larger than the arc radius of the outermost through hole 31. The arc radius of the second intermediate through hole 33 is larger than the arc radius of the first intermediate through hole 32. The arc radius of the innermost through hole 34 is larger than the arc radius of the second intermediate through hole 33.
In the following description, the direction in which the through hole 30 extends when viewed in the axial direction will be referred to as the "stretching direction." The directions in which the outermost through hole 31, the first intermediate through hole 32, the second intermediate through hole 33, and the innermost through hole 34 extend when viewed in the axial direction are referred to as a "first stretching direction" and a "second stretching direction," respectively. They will be referred to as the "third stretching direction" and the "fourth stretching direction."

When viewed in the axial direction, among the outermost through hole 31, the first intermediate through hole 32, and the second intermediate through hole 33, the farther the through hole 30 is located on the outer side in the radial direction, the shorter the dimension in the extending direction of the through hole 30 is. That is, the dimension of the outermost through hole 31 in the first stretching direction is shorter than the dimension of the first intermediate through hole 32 in the second stretching direction. The dimension of the first intermediate through hole 32 in the second extending direction is shorter than the dimension of the second intermediate through hole 33 in the third extending direction.
In the innermost through hole 34, one of the two ends in the fourth stretching direction does not extend to the radially outer edge 20b of the rotor core 20, and the dimension of the innermost through hole 34 in the fourth stretching direction is It is shorter than the dimension of the second intermediate through hole 33 in the third extending direction. Note that the radially outer edge portion 20b of the rotor core 20 is a region of the rotor core 20 that is inside the outer circumferential end of the rotor core 20 in the radial direction, and includes the outermost through hole 31, the first intermediate through hole 32, and the second intermediate through hole. Both ends of the through hole 33 in the extending direction and an end of the innermost through hole 34 on the −θ side in the extending direction are arranged.

Both ends of the outermost through hole 31, the first intermediate through hole 32, and the second intermediate through hole 33 in the extending direction and the −θ side end of the innermost through hole 34 in the circumferential direction are the radial outer edge of the rotor core 20. 20b, hereinafter referred to as the outer end.
The -θ side outer ends of the outermost through hole 31, the first intermediate through hole 32, the second intermediate through hole 33, and the innermost through hole 34 are connected to the first outer end 31a, the first outer end 32a, and the -θ side. They are referred to by reference numerals as a first outer end portion 33a and a first outer end portion 34a. The +θ side outer ends of the outermost through hole 31, the first intermediate through hole 32, and the second intermediate through hole 33 are defined as a second outer end 31b, a second outer end 32b, and a second outer end 33b. Called with a sign.
Hereinafter, when referring to the first outer end of any one of the through holes 30, it is simply referred to as the first outer end 30a, and when referring to the second outer end of any of the through holes 30, it is simply referred to as the second outer end. It is also called the end portion 30b. The radial positions of the first outer end 30a and the second outer end 30b are the same.

In the magnetic pole intermediate portion M, a region located on the -θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M is referred to as a first region P1, and a region located on the +θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M. The area is called a second area P2. In this embodiment, the circumferential center IM of the magnetic pole intermediate portion M is provided at a position that coincides with the q-axis of the rotor core 20. However, the positions of the circumferential center IM of the magnetic pole intermediate portion M and the q-axis may not coincide with each other.
The first outer end portion 30a is arranged in the first region P1. A second outer end portion 30b is arranged in the second region.
In the fourth stretching direction, the second end 34m of the innermost through hole 34, which is the end opposite to the first outer end 34a, does not extend to the radial outer edge 20b of the rotor core 20. That is, the innermost through hole 34 does not have a second outer end. In this way, in the through-hole group 130, the innermost through-hole 34 located radially innermost among the plurality of through-holes 30 has only one outer end. Thereby, in the rotor core 20, the magnetic path MP in the region radially inner than the second intermediate through hole 33 and the innermost through hole 34 can be easily formed into a suitable shape.

In this embodiment, the number of first outer end portions 30a arranged in the first region P1 is four, and the number of second outer end portions 30b arranged in the second region P2 is three. Thus, the number of second outer ends 30b arranged in the second region P2 is smaller than the number of first outer ends 30a arranged in the first region P1. As a result, when the circumferential center IM of the magnetic pole intermediate portion M is set as the axis of symmetry, the through holes 30 can be arranged asymmetrically, improving both the performance during startup and the efficiency during normal rotation of the rotating electric machine 1. It becomes possible to make the shape of the through hole 30 into a suitable shape. The number of second outer ends 30b arranged in the second region P2 is one less than the number of first outer ends 30a arranged in the first region P1. Thereby, the shape of the outermost through hole 31 disposed at the outermost position in the radial direction in the second region P2 can be made into a suitable shape so that the performance of the rotating electric machine 1 at startup can be improved.

In this embodiment, the second end 34m of the innermost through hole 34 is located on the −θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M. That is, the second end portion 34m is arranged in the first region P1. Thereby, the dimension between the center through hole 20a and the innermost through hole 34 can be suitably secured, so that the strength of the rotor core 20 can be maintained.
The position of the second end portion 34m is not limited to the example of this embodiment, and may be placed on the circumferential center IM of the magnetic pole intermediate portion M, or may be placed on the second region P2. The strength of the rotor core 20 due to the dimension between the center through hole 20a and the innermost through hole 34, and the strength of the through hole group 130 having the innermost through hole 34 and other through holes arranged on the +θ side of the through hole group 130 The position of the second end portion 34m may be changed as appropriate, taking into account the dimensions of the magnetic pole portion P between the through hole group 130.

<Arrangement of outer end portions 30a, 30b in circumferential direction>
As shown in FIG. 3, the circumferential angles τ11 to τ18 and τ21 to τ26 between the circumferential ends of the outer ends 30a and 30b of the through hole 30 and the circumferential center IM of the magnetic pole intermediate portion M are defined as follows. The arrangement of the outer end portions 30a and 30b in the circumferential direction will be described in more detail. Note that in FIG. 3, illustration of components other than the rotor core 20 is omitted for the sake of explanation.
The circumferential angles τ11, τ13, τ15, and τ17 are the circumferential ends of the first outer ends 31a, 32a, 33a, and 34a that are closer to the circumferential center IM of the magnetic pole intermediate portion M, and the circumferential angles of the first outer ends 31a, 32a, 33a, and 34a, respectively, and This is the circumferential angle between the circumferential center IM and the circumferential center IM.
The circumferential angles τ12, τ14, τ16, and τ18 are the circumferential ends of the first outer ends 31a, 32a, 33a, and 34a that are far from the circumferential center IM of the magnetic pole intermediate portion M, and the circumferential angles of the magnetic pole intermediate portion M, respectively. This is the circumferential angle between the circumferential center IM and the circumferential center IM.
The circumferential angles τ21, τ23, and τ25 are the circumferential ends of the second outer ends 31b, 32b, and 33b that are closer to the circumferential center IM of the magnetic pole intermediate portion M, and the circumferential center of the magnetic pole intermediate portion M, respectively. This is the circumferential angle between the IM and the IM.
The circumferential angles τ22, τ24, and τ26 are the circumferential end of the second outer end portions 31b, 32b, and 33b that is far from the circumferential center IM of the magnetic pole intermediate portion M, and the circumferential center IM of the magnetic pole intermediate portion M, respectively. is the circumferential angle between

In the outermost through hole 31, the second outer end 31b has a larger circumferential dimension than the first outer end 31a. That is, the second outer end 30b disposed in the second region P2 has at least one second outer end 30b having a larger circumferential dimension than the first outer end 30a disposed in the first region P1. include. As a result, the through holes 30 can be arranged asymmetrically when the circumferential center IM of the magnetic pole intermediate portion M is set as the axis of symmetry, so that both the performance at startup and the efficiency during normal rotation of the rotating electric machine 1 can be improved. In this way, the shape of the through hole 30 can be made into a suitable shape.

Further, in the through-hole group 130, the outermost through-hole 31 located at the outermost radial direction among the plurality of through-holes 30 has a first outer end 31a, which is an outer end located in the first region P1, and a first outer end 31a, which is an outer end located in the first region P1. a second outer end 31b that is an outer end located in the second region P2, and the circumferential dimension of the second outer end 31b is larger than the circumferential dimension of the first outer end 31a. . That is, τ12-τ11<τ22-τ21 is satisfied. As a result, it is possible to increase the circumferential width of the second outer end portion 31b disposed in the second region P2 and ensure a large cross-sectional area of the outermost through hole 31. The arrangement area of the body 40 can also be increased. Therefore, the performance of the rotating electric machine 1 at startup can be improved.

The circumferential angle τ11 between the circumferential end of the first outer end 31a that is closer to the circumferential center IM of the magnetic pole intermediate portion M and the circumferential center IM is the circumferential angle τ11 between the circumferential center IM of the second outer end 31b. This angle is ±1° with respect to the circumferential angle τ21 between the circumferential end on the side closer to IM and the circumferential center IM. That is, τ11=τ21±1° is satisfied. This can prevent the magnetic path MP located radially outward from the outermost through hole 31 from becoming too narrow, thereby improving the torque at startup while maintaining a suitable flow of magnetic flux during normal rotation. can. Further, in the rotor core 20, a region disposed radially outward from the outermost through hole 31 can be secured, so that the strength of the rotor core 20 can be increased.

In each of the first region P1 and the second region P2, two or more circumferential ends including both circumferential ends of the outer ends 30a and 30b are provided at intervals in the circumferential direction, and k is 2 or more. When expressed as an integer, the circumferential angle between the (k+2)th closest circumferential end to the circumferential center IM among the circumferential ends located in the first region P1 and the circumferential center IM is the second region P1. This is an angle that is ±1° with respect to the circumferential angle between the circumferential end that is kth closest to the circumferential center IM among the circumferential ends located at P2 and the circumferential center IM. That is, when k is an integer satisfying k≧2, τ1(k+2)=τ2k±1° is satisfied.
In this embodiment, when k=2, τ14=τ22±1°, when k=3, τ15=τ23±1°, when k=4, τ16=τ24±1°, and when k=5, τ17=τ25 ±1°, when k=6, τ18=τ26±1° is satisfied.

Since the circumferential ends are arranged in this manner, the first outer end 31a and the first outer end 32a are arranged at positions overlapping the second outer end 31b with the circumferential center IM as the axis of symmetry. The first outer end portions 33a and 34a are arranged line-symmetrically with the second outer end portions 32b and 33b, respectively, with the circumferential center IM as an axis of symmetry.
As a result, the circumferential width of the second outer end 31b of the outermost through hole 31 can be increased to ensure a large cross-sectional area of the outermost through hole 31, so that the conductor 40 disposed within the outermost through hole 31 can be The arrangement area can also be increased. Therefore, the performance of the rotating electric machine 1 at startup can be improved. Furthermore, when viewed in the axial direction, the cross-sectional area in the first region P1 of the outermost through hole 31 is smaller than that in the second region P2, but the number of first outer end portions 30a in the first region P1 is smaller than that in the first region P1. The number is greater than the number of second outer ends 30b in the second region P2. For this reason, the plurality of through-holes are arranged so that the difference between the sum of the cross-sectional areas of the through-holes 30 in the first region P1 and the sum of the cross-sectional areas of the through-holes 30 in the second region P2 does not become excessively large when viewed in the axial direction. 30 can be placed. Thereby, performance can be improved when the rotor 10 starts rotating in either the +θ side or the -θ side.

<Width of through hole 30>
The width of the through hole 30 is the dimension in the direction perpendicular to the extending direction of each through hole 30 when viewed in the axial direction.
When viewed in the axial direction, the width of the outermost through hole 31 increases from the first outer end 31a toward the second outer end 31b. As a result, the circumferential width of the outermost through hole 31 on the second outer end 31b side can be increased to ensure a large cross-sectional area of the outermost through hole 31, so that the conductor disposed inside the outermost through hole 31 can The arrangement area of 40 can also be increased. Therefore, the performance of the rotating electric machine 1 at startup can be improved.
When viewed in the axial direction, the width of the first intermediate through hole 32, the width of the second intermediate through hole 33, and the width of the innermost through hole 34 excluding the second end 34m are all uniform in the stretching direction. There is. As a result, even when the cross-sectional area of the outermost through hole 31 is increased, the magnetic path MP between the outermost through hole 31 and the first intermediate through hole 32, the first intermediate through hole 32 and the second intermediate through hole 33 It is possible to prevent the magnetic path MP between the second intermediate through hole 33 and the innermost through hole 34 from becoming too narrow.
In the second end 34m, the width of the innermost through hole 34 in the fourth stretching direction becomes smaller toward the tip of the second end 34m. Thereby, in the rotor core 20, the dimension between the center through hole 20a and the innermost through hole 34 can be secured, so that the mechanical strength of the rotor core 20 can be maintained.

<Bridge portion 30g of through hole 30>
The through-hole group 130 includes three or more through-holes 30, and in the through-hole group 130, the through-holes excluding the through-hole 30 located most radially outside and the through-hole 30 located most radially inside At least one of the through holes 30 is provided with a bridge portion 30g that connects a first edge 30e1 on the radially inner side of the through hole 30 and a second edge 30e2 on the radially outer side. In this embodiment, as shown in FIG. 2, the outermost through hole 31 and the innermost through hole 34 are not provided with the bridge portion 30g, and the first intermediate through hole 32 and the second intermediate through hole 33 are provided with no bridge portion 30g. Bridge portions 30g are arranged at positions overlapping with the circumferential center IM. As a result, the mechanical strength of the rotor core 20 can be suitably maintained. Further, since the bridge portion 30g that electrically separates the conductor 40 is not arranged in the outermost through hole 31, the performance at startup can be suitably improved.
Note that the bridge portion 30g may be provided in only one of the first intermediate through hole 32 and the second intermediate through hole 33. The number of bridge portions 30g provided in each through hole 30 is not limited to one, but may be two or more. Further, the bridge portion 30g may be arranged at a position other than the circumferential center IM.

<Characteristic evaluation of rotor core 20>
Hereinafter, the results of comparing the strength of the rotor core, the performance at startup, and the efficiency during normal rotation in a plurality of rotor cores with different shapes of through holes will be explained using Table 1. Note that the rotor core of Example 1 in Table 1 is the rotor core 20 shown in FIG. 2, the rotor core of Comparative Example 1 is the rotor core 200 shown in FIG. The rotor core of Example 2) is the rotor core 201 shown in FIG. Conductors are arranged in the through holes of the rotor cores of Example 1, Comparative Example 1, and Comparative Example 2, respectively.
Table 1 shows the characteristics when each rotor core is rotated in the +θ direction (CW: clockwise) or −θ direction (CCW: counter-clockwise).

The rotor core 200 shown in FIG. 7 has a plurality of through holes 230, including a first through hole 231, a second through hole 232, a third through hole 233, and a fourth through hole 234. The through holes 230 are arcuate and concentric with each other when viewed in the axial direction. The arc radius of the through hole 230 that is radially inner is larger. The widths of the through holes 230 are the same. The plurality of through holes 230 have a line-symmetrical shape with respect to the circumferential center IM of the magnetic pole intermediate portion M as an axis of symmetry.

In FIG. 7, the through holes 30 of the rotor core 20 of Example 1 are shown overlapped by broken lines. As shown in FIG. 7, the positions of the first outer ends 230a of the rotor core 200 are the same as the positions of the first outer ends 30a of the rotor core 20.
As shown in FIG. 7, the second outer end 231b of the first through hole 231 of the rotor core 200 and the second outer end 232b of the second through hole 232 are the second outer end of the outermost through hole 31 of the rotor core 20. It is arranged at a position overlapping the portion 31b. The circumferential end of the second outer end 231b of the first through hole 231 of the rotor core 200 that is closer to the circumferential center IM is located at the circumferential center of the second outer end 31b of the outermost through hole 31 of the rotor core 20. The circumferential end of the second outer end 232b of the second through hole 232 of the rotor core 200 that is far from the circumferential center IM is disposed at the same position as the circumferential end of the second through hole 232 of the rotor core 200. It is arranged at the same position as the circumferential end of the second outer end 31b of the through hole 31 that is far from the circumferential center IM.
The second outer end 233b of the third through hole 233 of the rotor core 200 and the second outer end 234b of the fourth through hole 234 are respectively the second outer end 32b of the first intermediate through hole 32 of the rotor core 20 and the second outer end 234b of the third through hole 233 of the rotor core 200. It is arranged at the same position as the second outer end 33b of the intermediate through hole 33.

The rotor core 201 shown in FIG. 8 has the same shape as the rotor core 200 except that the shape of the first through hole 231 is different. More specifically, compared to the rotor core 200, the first through hole 231 of the rotor core 201 widens toward the outside in the radial direction when viewed from the axial direction. Therefore, the cross-sectional area of the first through hole 231 of the rotor core 201 is larger than that of the rotor core 200, and the arrangement area of the conductor 40 arranged inside the first through hole 231 is also larger.

The "structural rigidity" column shown in Table 1 shows the results of evaluating the mechanical strength of the rotor core. In Comparative Example 1, in which the cross-sectional area of the first through hole disposed at the outermost position in the radial direction was smaller than that in Comparative Example 2, the strength was very good. This is considered to be because, in Comparative Example 1, the radially outer dimension of the first through hole 231 in the rotor core 200 is ensured. Although the strengths of Example 1 and Comparative Example 2 were slightly inferior to Comparative Example 1, they were good results. It can be seen that the rotor core 20 of Example 1 has a structure in which deformation of the rotor core 20 is unlikely to occur during the manufacturing process of the rotor core 20 and during the rotor rotation.

The "starting load capacity" column shown in Table 1 shows the results of evaluating the load capacity required to start rotation of the rotor core.
Comparative Example 1 gave poor results. This is because in Comparative Example 1, the cross-sectional area of the first through hole 231 disposed at the outermost position in the radial direction is smaller than in Comparative Example 2 and Example 1, and the conductor disposed at the radially outer peripheral edge of the rotor core 200 This is thought to be because the area in which 40 is arranged is narrow. Therefore, in Comparative Example 1, it was not possible to suitably obtain torque due to Lorentz force at the time of startup.
Comparative Example 2, in which the conductor 40 was arranged in a wider area than Comparative Example 1, had good results. It has been shown that by expanding the outermost first through hole 231 in the radial direction to the outside in the radial direction as in Comparative Example 2 compared to Comparative Example 1, the area in which the conductor 40 is arranged can be increased and the performance at startup can be improved to some extent. However, the effect was limited.

The performance of Example 1 at startup was very good compared to Comparative Example 2. In Example 1, the through hole 30 has an asymmetric shape when the circumferential center IM is set as the axis of symmetry, and the position where the conductor 40 is arranged and the area of the arrangement region are optimized, so compared to Comparative Example 2. This is thought to be due to the fact that the Lorentz force at startup could be obtained more favorably.

The "performance at rated condition" column shown in Table 1 shows the results of evaluating the efficiency during normal rotation when the rotation speed of the rotor core is the rated speed.
In Example 1, Comparative Example 1, and Comparative Example 2, the through holes that serve as flux barriers are arranged in all cases, so the reluctance torque generated by the magnetic anisotropy of the rotor core allows for good rotation during normal rotation. I understand that.

From the above results, it can be seen that the rotor core 20 of Example 1 can satisfactorily improve the performance at startup while suitably ensuring strength and rotational efficiency during normal rotation.

Although Table 1 shows only the evaluation results of the rotor core 20 of Example 1 in the counterclockwise direction, the evaluation results of all items in the clockwise direction were as good as the evaluation results in the clockwise direction. Ta. However, in the rotor core 20 of Example 1, the shape of the through hole 30 is asymmetrical with respect to the circumferential center IM of the magnetic pole intermediate portion M. It was possible to further improve performance by starting the rotation around the periphery.

As described above, the rotor core 20 of the present embodiment is a rotor core 20 that is rotatable around the central axis J, and includes a plurality of magnetic pole parts P arranged at intervals in the circumferential direction, and a plurality of magnetic pole parts P arranged at intervals in the circumferential direction. A plurality of magnetic pole intermediate parts M are respectively located between the magnetic pole parts P, and each of the plurality of magnetic pole intermediate parts M has a through hole including a plurality of through holes 30 arranged at intervals in the radial direction. Each through hole 30 has an outer end portion 30a, 30b located at the radially outer edge portion 20b of the rotor core 20, and in each of the plurality of magnetic pole intermediate portions M, each through hole 30 has an outer end portion 30a, 30b located at the radial outer edge portion 20b of the rotor core 20. Outer end portions 30a and 30b are arranged in the first region P1 and the second region P2, which are arranged on both sides of the center IM, respectively, and the number of the second outer end portions 30b arranged in the second region P2 is as follows. The number is smaller than the number of first outer end portions 30a arranged in the first region P1.

As a result, the circumferential width of one of the second outer ends 30b disposed in the second region P2 is increased to enlarge the through hole 30, and the arrangement area of the conductor 40 disposed within the through hole 30 is enlarged. can do. Furthermore, even if the cross-sectional area of the through-holes 30 is increased when viewed from the axial direction, it is possible to prevent the magnetic path MP between the through-holes 30 from becoming too narrow, and the magnetic flux can be suitably distributed in the magnetic path MP. can flow. Therefore, the torque at startup can be improved while suitably maintaining the flow of magnetic flux during normal rotation. Furthermore, since the dimensions of the rotor core 20 near the through hole 30 can be suitably secured, the strength of the rotor core 20 can be improved. Furthermore, although torque ripples may occur when the rotor 10 rotates around the central axis J and the position of the magnetic path MP in the circumferential direction relative to the stator 3 moves, the width of each magnetic path MP can be appropriately secured. , torque ripple can be reduced.

Further, the rotor 10 of this embodiment includes the above-described rotor core 20 and a conductor 40 located within the through hole 30. The Lorentz force generated in the conductor 40 can improve the torque at the time of starting the rotor 10.

Further, the rotating electrical machine 1 of the present embodiment includes the above-described rotor 10 and the stator 3 located on the outside of the rotor 10 in the radial direction.
As a result, it is possible to obtain the rotating electric machine 1 that satisfactorily ensures the strength of the rotor 10 and the efficiency of rotation during normal rotation, while improving the performance during startup.

The present invention is not limited to the above-described embodiments, and other configurations may be adopted within the scope of the technical idea of the present invention.

In the example shown in FIG. 2, in the magnetic pole intermediate portion M, the first region P1 is arranged on the −θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M, and on the +θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M. Although the second region P2 having a smaller number of second outer ends 30b than the number of first outer ends 30a arranged in the first region P1 has been arranged, the present invention is not limited to this example.
For example, the first region P1 is arranged on the +θ side of the circumferential center IM of the magnetic pole intermediate portion M, and the first outer region P1 is arranged on the −θ side of the circumferential center IM of the magnetic pole intermediate portion M. The second region P2 having a smaller number of second outer end portions 30b than the number of end portions 30a may be arranged.

Further, as shown in FIG. 4, two circumferentially adjacent through hole groups 130 may be mirror symmetrical with respect to the d-axis as an axis of symmetry. The partially enlarged view of the rotor core 20 shown in FIG. 4 shows two through-hole groups 130 including a through-hole group 130A and a through-hole group 130B arranged on the −θ side of the through-hole group 130A. . The through-hole group 130A and the through-hole group 130B are mirror-image symmetrical with respect to the d-axis between the two through- hole groups 130A and 130B.
That is, in the through hole group 130A, the −θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M is the first region P1, and the +θ side is the second region P2. In the through-hole group 130B, the +θ side with respect to the circumferential center IM of the magnetic pole intermediate portion M is the first region P1, and the −θ side is the second region P2. Thereby, performance at startup can be improved regardless of whether the rotor core 20 is started to rotate clockwise or counterclockwise.

Further, the number of through holes 30 that each through hole group 130 has is not limited to four, and it is sufficient that it has at least two through holes 30, an outermost through hole and an innermost through hole. For example, the number of through holes 30 that each through hole group 130 has may be two, three, or four or more.
For example, in the rotor core 20 shown in FIG. 4, each through-hole group 130 has two through-holes 30, and no intermediate through-hole is arranged.

Further, the number of magnetic pole parts P of the rotor core 20 is not limited to four poles, and may be less than four poles or more than four poles. The number of magnetic pole parts P of the rotor 10 may be, for example, two poles, six poles, or eight poles.
FIG. 5 shows a rotor 10 having a six-pole structure. The six through-hole groups 130 are arranged at equal intervals along the circumferential direction of the rotor 10. Since the magnetic pole portions P are provided between the through hole groups 130 adjacent to each other in the circumferential direction, the rotor 10 shown in FIG. 5 is provided with six magnetic pole portions P.

Further, as shown in FIG. 6, the bridge portion 30g may not be provided in the through hole 30. In the rotor core 20 of FIG. 6, the bridge portion 30g is not provided in the first intermediate through hole 32 and the second intermediate through hole 33, compared to the rotor core 20 shown in FIG.
For example, if the conductor 40 is electrically separated by the bridge portion 30g, the Lorentz force generated when the rotor 10 starts rotating may not be obtained appropriately. By not providing the bridge portion 30g, it becomes possible to obtain the Lorentz force generated at the time of startup more appropriately.

Further, in the rotor core 20 shown in FIG. 2, the shape of the plurality of through holes 30 is an arc shape that is convex radially inward when viewed in the axial direction, but is not limited to this example. It may also be in the form of a polygonal line that is convex inward in the radial direction. Furthermore, one set of through-hole groups 130 may include both arc-shaped through-holes 30 and polygonal-line-shaped through holes 30.

Further, the rotor 10 may include a magnet located within the through hole 30. For example, a ferrite magnet may be provided in at least one through hole 30 at a position overlapping the circumferential center IM of the magnetic pole intermediate portion M. Alternatively, ferrite magnets may be provided on the outer end portions 30a and 30b of at least one through hole 30, respectively. The type of magnet is not particularly limited, and the magnet may be a neodymium magnet.
In this case, the torque of the rotor 10 can be improved by the magnetic force of the magnet. The magnet may be placed in the through hole 30, and after the magnet is placed, the through hole 30 may be filled with a molten conductor 40, so that the inside of the through hole 30 is closed by the conductor 40 and the magnet. .

Further, the through hole 30 does not have to penetrate the rotor core 20 in the axial direction. The through hole 30 may be open at the end surface of the rotor core 20 in the axial direction.

The through hole 30 is not particularly limited as long as it can suppress the flow of magnetic flux. In the embodiment described above, the conductor 40 is arranged inside the through hole 30, but the inside of the through hole 30 may be a void. Further, the through hole 30 may be formed by filling the void with a nonmagnetic material such as resin.

The use of the rotating electric machine to which the present invention is applied is not particularly limited. The rotating electrical machine may be mounted on a vehicle, or may be mounted on equipment other than the vehicle, for example. The configurations described above in this specification can be combined as appropriate within a mutually consistent range.

DESCRIPTION OF SYMBOLS 1... Rotating electric machine, 3... Stator, 10... Rotor, 20... Rotor core, 20b... Radial outer edge of rotor core, 30... Through hole, 30a... First outer end (outer end), 30b... Second outer end part (outer end), 30e1...first edge, 30e2...second edge, 30g...bridge part, 31...outermost through hole, 34...innermost through hole, 40...conductor, 130...through hole group , IM...Circumferential center of the magnetic pole intermediate part, J...Central axis line, M...Magnetic pole intermediate part, P...Magnetic pole part, P1...first region, P2...second region

Claims (12)

1. A rotor core rotatable around a central axis,
   a plurality of magnetic pole parts arranged at intervals in the circumferential direction;
   a plurality of magnetic pole intermediate portions each located between the circumferentially adjacent magnetic pole portions;
   Equipped with
   Each of the plurality of magnetic pole intermediate portions has a through hole group including a plurality of through holes arranged at intervals in the radial direction,
   Each of the through holes has an outer end located at a radially outer edge of the rotor core,
   In each of the plurality of magnetic pole intermediate portions, the outer end portions are respectively disposed in a first region and a second region that are arranged on both sides of the circumferential center of the magnetic pole intermediate portion,
   The number of the outer end portions arranged in the second region is smaller than the number of the outer end portions arranged in the first region.
2. The outer end portion disposed in the second region includes at least one outer end portion having a larger circumferential dimension than the outer end portion disposed in the first region. rotor core.
3. In the through hole group, the outermost through hole located radially outermost among the plurality of through holes has a first outer end portion that is the outer end portion located in the first region, and a first outer end portion that is the outer end portion located in the first region, and a first outer end portion that is the outer end portion located in the first region. a second outer end portion that is the outer end portion located at
   The rotor core according to claim 2, wherein a circumferential dimension of the second outer end is larger than a circumferential dimension of the first outer end.
4. The rotor core according to claim 3, wherein the width of the outermost through hole increases from the first outer end toward the second outer end when viewed in the axial direction.
5. The circumferential angle between the circumferential end of the first outer end closer to the circumferential center and the circumferential center is equal to the circumferential angle of the second outer end closer to the circumferential center. The rotor core according to claim 3 or 4, wherein the angle is ±1° with respect to the circumferential angle between the direction end and the circumferential center.
6. In each of the first region and the second region, two or more circumferential ends including both circumferential ends of the outer end portion are provided at intervals in the circumferential direction,
   When k is an integer of 2 or more, the circumference between the circumferential edge that is (k+2)th closest to the circumferential center among the circumferential edges located in the first area and the circumferential center; The direction angle is ±1° with respect to the circumferential angle between the circumferential end that is kth closest to the circumferential center among the circumferential ends located in the second region and the circumferential center. The rotor core according to any one of claims 3 to 5, which has an angle of .
7. The rotor core according to any one of claims 1 to 6, wherein the number of the outer ends arranged in the second region is one less than the number of the outer ends arranged in the first region. .
8. The rotor core according to claim 7, wherein in the through-hole group, the innermost through-hole located radially innermost among the plurality of through-holes has only one outer end.
9. The through-hole group includes three or more through-holes,
   In the through-hole group, at least one of the through-holes, excluding the through-hole located at the radially outermost position and the through-hole located at the radially innermost position, includes a first hole located at the radially inner side of the through-hole. The rotor core according to any one of claims 1 to 8, further comprising a bridge portion connecting the edge portion and the radially outer second edge portion.
10. The rotor core according to any one of claims 1 to 9,
    a conductor located within the through hole;
    A rotor.
11. The rotor according to claim 10, comprising a magnet located within the through hole.
12. A rotor according to claim 10 or 11;
    a stator located on the radially outer side of the rotor;
    A rotating electric machine equipped with

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