JP2024047791A - Rotor and rotary electric machine - Google Patents

Abstract

To provide a rotor and a rotary electric machine capable of increasing efficiency with a simple configuration.SOLUTION: The rotor includes: a rotor core 20 provided with a plurality of magnet holes 31a, 31b and a plurality of housing parts 33 extending axially about a central axis J; a plurality of magnetic pole parts 70 having magnets 41a, 41b disposed in the magnet holes 31a, 31b; and a magnetostrictive part 50 disposed in the housing parts 33 and having a specific magnetic permeability that changes with elastic deformation. One magnetic pole part 70 has two magnets 41a, 41b. The two magnets 41a, 41b are spaced apart from each other in a circumferential direction and extend away from each other in the circumferential direction from the inner side in a radial direction toward the outer side in the radial direction as seen in the axial direction. The magnetostrictive part 50 is disposed on the d-axis in the magnetic pole part 70 outside the two magnets 41a, 41b in the radial direction and extends in the circumferential direction.SELECTED DRAWING: Figure 3

Description

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

Automotive traction motors are required to operate over a wide range of conditions, from low-speed, high torque to high-speed rotation and high output, making it difficult to improve efficiency in all operating ranges. In recent years, attention has been focused on "variable field magnet technology," which can vary the effective magnetic flux of the motor depending on the operating point during operation.

Patent Document 1 discloses a rotor core that includes flux short-circuiting members that are arranged in multiple flux barriers between adjacent magnet insertion holes and have a magnetic flux path from a first pole of one of adjacent permanent magnets to a second pole of the other, at least a part of which is made of a super magnetostrictive material. In the rotor core described in Patent Document 1, when the rotor rotates at high speed, the magnetic permeability of the super magnetostrictive material is improved compared to when the rotor rotates at low speed, thereby increasing the short-circuit magnetic flux.

JP 2004-343842 A

Considering the average efficiency of the motor, it is preferable to reduce the magnetic flux by reducing the radial magnetic permeability of the rotor when the rotor rotates at high speed, but in the rotor core described in Patent Document 1, the magnetic permeability is increased when the rotor rotates at high speed. Therefore, the effect on improving the average efficiency of the motor and the system efficiency is small. In addition, the rotor core described in Patent Document 1 is provided with weights and compression springs to change the magnetic permeability, which results in an increase in size and cost.

The present invention was made in consideration of the above points, and one of its objectives is to provide a rotor and rotating electric machine that can increase efficiency with a simple configuration.

One aspect of the rotor of the present invention comprises a rotor core provided with a plurality of magnet holes and a plurality of housings extending in the axial direction around a central axis, a plurality of magnetic pole portions having magnets arranged in the magnet holes, and a magnetostrictive portion arranged in the housing portion, the relative permeability of which changes with elastic deformation. One of the magnetic pole portions has two magnets. The two magnets are arranged at a distance from each other in the circumferential direction, and extend in a direction that separates them from each other in the circumferential direction as they move from the radially inner side to the radially outer side as viewed in the axial direction. The magnetostrictive portion is arranged on the d-axis of the magnetic pole portions, radially outside the two magnets, and extends in the circumferential direction.

One embodiment of the rotating electric machine of the present invention comprises the rotor described above and a stator facing the rotor.

According to one aspect of the present invention, it is possible to increase the efficiency of a rotor and a rotating electric machine with a simple configuration.

FIG. 1 is a cross-sectional view showing a rotating electrical machine having a rotor according to this embodiment. FIG. 2 is a cross-sectional view showing a part of a rotating electric machine having a rotor according to an embodiment, taken along line II-II in FIG. FIG. 3 is a cross-sectional view showing a magnetic pole portion of a rotor and a part of a stator core according to one embodiment. FIG. 4 is a graph showing simulation results of the variable field width and torque when the first angle is changed in the rotor of one embodiment. FIG. 5 is a graph showing simulation results of the variable field width and torque when the first angle is changed in a rotor in which the thickness of the magnetostrictive portion is doubled compared to FIG. FIG. 6 is a graph showing simulation results of the variable field width and torque when the first angle is changed in a rotor in which the thickness of the magnetostrictive portion is three times that of FIG. FIG. 7 is a graph showing the variable field width when the second angle is changed in the rotor of one embodiment.

The rotor and rotating electric machine according to the embodiment of the present invention will be described below with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure may differ from the actual structure in order to make each configuration easier to understand.

The Z-axis direction shown in each figure is an up-down direction with the positive side being the "upper side" and the negative side being the "lower side". The central axis J shown in each figure is an imaginary line that is parallel to the Z-axis direction and extends in the up-down direction. In the following description, the axial direction of the central axis J, i.e., the direction parallel to the up-down direction, is simply referred to as the "axial direction", the radial direction centered on the central axis J is simply referred to as the "radial direction", and the circumferential direction centered on the central axis J is simply referred to as the "circumferential direction". The arrow θ shown in each figure indicates the circumferential direction. The arrow θ points clockwise around the central axis J when viewed from above. In the following description, the side to which the arrow θ points in the circumferential direction based on a certain object, i.e., the side moving clockwise when viewed from above, is referred to as the "one circumferential side", and the side opposite to the side to which the arrow θ points in the circumferential direction based on a certain object, i.e., the side moving counterclockwise when viewed from above, is referred to as the "other circumferential side".

Note that the terms "upper", "upper side", and "lower side" are simply names used to describe the relative positions of the various parts, and the actual relative positions may be other than those indicated by these names.

[Rotary Electric Machine]
1 is a cross-sectional view showing a rotating electric machine 1 according to the present embodiment. The rotating electric machine 1 according to the present embodiment is an inner rotor type rotating electric machine. In the present embodiment, the rotating electric machine 1 is a three-phase AC type rotating electric machine. The rotating electric machine 1 is, for example, a three-phase motor that is driven by being supplied with a three-phase AC power source. The rotating electric machine 1 includes a housing 2, a rotor 10, a stator 60, a bearing holder 4, and bearings 5a and 5b.

The housing 2 contains the rotor 10, the stator 60, the bearing holder 4, and the bearings 5a and 5b. The bottom of the housing 2 holds the bearing 5b. The bearing holder 4 holds the bearing 5a. The bearings 5a and 5b are, for example, ball bearings.

The stator 60 is located radially outside the rotor 10. The stator 60 has a stator core 61, an insulator 64, and multiple coils 65. The stator core 61 has a core back 62 and multiple teeth 63. The core back 62 is located radially outside the rotor core 20 described below. Note that the coils 65 are not shown in the following Figures 2 to 3. The insulators 64 are not shown in the following Figures 2 to 3.

FIG. 2 is a cross-sectional view of the rotating electric machine 1 taken along line II-II in FIG.
The core back 62 has an annular shape surrounding the rotor core 20. The core back 62 has an annular shape centered on the central axis J.

The teeth 63 extend radially inward from the core back 62. The teeth 63 are arranged in a line at intervals in the circumferential direction. The teeth 63 are arranged at equal intervals around the circumference. In this embodiment, 48 teeth 63 are provided. In other words, the number of slots 67 in the rotating electric machine 1 of this embodiment is 48. As shown in FIG. 3, each of the teeth 63 has a base portion and an umbrella portion.

The bases of the teeth 63 extend radially inward from the core back 62. The circumferential dimension of the bases is the same throughout the entire radial direction. The circumferential dimension of the bases may decrease radially inward.

The umbrella portion of the tooth 63 is provided at the radially inner end of the base. The umbrella portion protrudes from the base on both sides in the circumferential direction. The circumferential dimension of the umbrella portion is greater than the circumferential dimension at the radially inner end of the base. The radially inner surface of the umbrella portion is a curved surface along the circumferential direction. When viewed in the axial direction, the radially inner surface of the umbrella portion extends in an arc shape centered on the central axis J. The radially inner surface of the umbrella portion faces the outer peripheral surface of the rotor core 20 described later with a gap in the radial direction. The umbrella portions of the teeth 63 adjacent to each other in the circumferential direction are arranged side by side with a gap in the circumferential direction.

The coils 65 are attached to the stator core 61. As shown in FIG. 1, the coils 65 are attached to the teeth 63 via the insulators 64. In this embodiment, the coils 65 are distributed wound. That is, each coil 65 is wound across the teeth 63. In this embodiment, the coils 65 are full-pitch wound. That is, the circumferential pitch between the slots of the stator 60 into which the coils 65 are inserted is equal to the circumferential pitch of the magnetic poles generated when a three-phase AC power supply is supplied to the stator 60. The number of poles of the rotating electric machine 1 of this embodiment is 8. In other words, the rotating electric machine 1 of this embodiment is an 8-pole, 48-slot rotating electric machine. Thus, in the rotating electric machine 1 of this embodiment, when the number of poles is N, the number of slots is N×6.

[Rotor]
The rotor 10 is rotatable about a central axis J. As shown in Fig. 2, the rotor 10 has a shaft 11, a rotor core 20, a plurality of magnets 40, and a plurality of magnetostrictive portions 50. The shaft 11 is cylindrical and extends in the axial direction about the central axis J. As shown in Fig. 1, the shaft 11 is supported by bearings 5a and 5b so as to be rotatable about the central axis J.

The rotor core 20 is a magnetic body. The rotor core 20 is fixed to the outer peripheral surface of the shaft 11. The rotor core 20 has a through hole 21 that passes through the rotor core 20 in the axial direction. As shown in FIG. 2, the through hole 21 has a circular shape centered on the central axis J when viewed in the axial direction. The shaft 11 passes through the through hole 21. The shaft 11 is fixed in the through hole 21 by press fitting or the like. Although not shown in the figure, the rotor core 20 is constructed by stacking multiple electromagnetic steel plates in the axial direction.

The rotor core 20 has a plurality of magnet holes 30 and a plurality of housings 33. The plurality of magnet holes 30 penetrate the rotor core 20 in the axial direction. Each of the plurality of magnet holes 30 houses one magnet 40. The method of fixing the magnet 40 in the magnet hole 30 is not particularly limited. The plurality of magnet holes 30 are classified into a plurality of sets, with a pair of magnet holes 31a, 31b as one set. The number of sets of magnet holes 30 provided in the rotor core 20 is the same as the number of poles of the rotor 10. Therefore, the rotor core 20 is provided with eight sets of magnet holes 30, with each set being a pair of magnet holes 31a, 31b. The sets of magnet holes 30 are arranged with a gap between them in the circumferential direction.

The type of the magnets 40 is not particularly limited. The magnets 40 may be, for example, neodymium magnets or ferrite magnets. The magnets 40 are classified into a plurality of sets, with a pair of magnets 41a, 41b as one set. A pair of magnets 41a, 41b constitutes one pole. Therefore, the number of sets of magnets 40 matches the number of poles of the rotor 10 (8 in this embodiment). The number of poles of the rotor 10 in this embodiment is 8. Therefore, the rotor core 20 in this embodiment is provided with 8 sets of magnet holes 30, with each set being a pair of magnet holes 31a, 31b. The sets of magnet holes 30 are arranged with a gap between them in the circumferential direction.

The rotor 10 has a plurality of magnetic pole portions 70, each of which includes a pair of magnet holes 31a, 31b and a pair of magnets 41a, 41b. The rotor 10 of this embodiment is provided with eight magnetic pole portions 70. The magnetic pole portions 70 are arranged at equal intervals around the circumference in the circumferential direction. The magnetic pole portions 70 include a plurality of magnetic pole portions 70N with a magnetic pole of N pole on the outer peripheral surface of the rotor core 20 and a magnetic pole portion 70S with a magnetic pole of S pole on the outer peripheral surface of the rotor core 20 (four in this embodiment). The magnetic pole portions 70N and the four magnetic pole portions 70S are arranged alternately along the circumferential direction. The configuration of each magnetic pole portion 70 is the same, except that the magnetic poles on the outer peripheral surface of the rotor core 20 are different and the circumferential positions are different.

FIG. 3 is a cross-sectional view showing the magnetic pole portion of the rotor 10 and a part of the stator core.
In the magnetic pole portion 70, the pair of magnet holes 31a, 31b are arranged with a gap between them in the circumferential direction. One magnet hole 31a is located on one circumferential side (+θ side) of the other magnet hole 31b. The pair of magnet holes 31a, 31b extend in a substantially linear manner in a direction inclined obliquely with respect to the radial direction when viewed in the axial direction. The pair of magnet holes 31a, 31b extend in a direction that separates them from each other in the circumferential direction as they move from the radial inner side to the radial outer side when viewed in the axial direction. In other words, the circumferential distance between the one magnet hole 31a and the other magnet hole 31b increases as they move from the radial inner side to the radial outer side. The one magnet hole 31a is located on one circumferential side as they move from the radial inner side to the radial outer side. The other magnet hole 31b is located on the other circumferential side (-θ side) as they move from the radial inner side to the radial outer side. The radially outer ends of the pair of magnet holes 31a, 31b are located at the radially outer peripheral edge of the rotor core 20.

When viewed in the axial direction, one magnet hole 31a and the other magnet hole 31b are arranged on either side of the magnetic pole center line IL1 shown in FIG. 3, which constitutes the d-axis. The magnetic pole center line IL1 is an imaginary line that passes through the circumferential center of the magnetic pole portion 70 and the central axis J, and extends in the radial direction. When viewed in the axial direction, one magnet hole 31a and the other magnet hole 31b are arranged symmetrically with respect to the magnetic pole center line IL1.

In this embodiment, the magnet holes 31a and 31b are rectangular. However, the magnet hole 30 may have flux barriers located at the radially inner end and the radially outer end. In this case, the flux barriers are provided so as to expand both ends of the magnet holes 31a and 31b in the length direction of the magnet holes 31a and 31b. The flux barrier is a part that can suppress the flow of magnetic flux. The flux barrier is not particularly limited as long as it can suppress the flow of magnetic flux, and may include a void portion or be filled with a resin portion or the like.

The pair of magnets 41a, 41b are housed in the pair of magnet holes 31a, 31b, respectively. More specifically, one magnet 41a is housed in one magnet hole 31a, and the other magnet 41b is housed in the other magnet hole 31b. The pair of magnets 41a, 41b are, for example, rectangular when viewed in the axial direction. The length of the pair of magnets 41a, 41b in the direction in which they extend is the same. The length of the magnets 41a, 41b in the direction perpendicular to the direction in which the pair of magnets 41a, 41b extend is the same.

The magnets 41a and 41b are, for example, rectangular parallelepiped-shaped. The magnets 41a and 41b are provided over almost the entire axial length of the magnet holes 31a and 31b. The pair of magnets 41a and 41b are arranged at a distance from each other in the circumferential direction. One magnet 41a is located on one circumferential side (+θ side) of the other magnet 41b.

One magnet 41a extends along one magnet hole 31a when viewed in the axial direction. The other magnet 41b extends along the other magnet hole 31b when viewed in the axial direction. The pair of magnets 41a, 41b extend in a substantially straight line in a direction inclined at an angle to the radial direction when viewed in the axial direction. The pair of magnets 41a, 41b extend in a direction that separates them circumferentially from each other as they move from the radially inner side to the radially outer side when viewed in the axial direction. In other words, the circumferential distance between one magnet 41a and the other magnet 41b increases as they move from the radially inner side to the radially outer side.

One magnet 41a is located on one circumferential side (+θ side) from the radial inside to the radial outside. The other magnet 41b is located on the other circumferential side (-θ side) from the radial inside to the radial outside. One magnet 41a and the other magnet 41b are arranged on either side of the magnetic pole center line IL1 in the circumferential direction when viewed in the axial direction. One magnet 41a and the other magnet 41b are arranged symmetrically with respect to the d axis (magnetic pole center line IL1) when viewed in the axial direction.

Here, the angle between the two magnets 41a, 41b is defined as the first angle α. The first angle is the angle between the surface of one magnet 41a facing radially outward and the surface of the other magnet 41b facing radially outward. In this embodiment, the first angle α is preferably 50° or more and 60° or less. By setting the first angle α to 50° or more and 60° or less, it is possible to provide a rotating electric machine 1 that increases the variable field width of the rotor 10 and enables efficient driving according to the rotation speed. Simulation results in which the first angle α is changed will be described later with reference to Figures 4 to 6.

Two magnets 41a, 41b are housed in magnet holes 31a, 31b, respectively. A gap S1 is provided between the inner side of magnet holes 31a, 31b and the radially inner side of magnets 41a, 41b. Magnet holes 31a, 31b are made larger than the dimensions of magnets 41a, 41b, taking into account ease of insertion of magnets 41a, 41b during the assembly process. By providing gap S1 between the radially inner side of magnets 41a, 41b and the inner side of magnet holes 31a, 31b, even when centrifugal force is applied when rotor 10 rotates, the radially outer side of magnets 41a, 41b can be reliably brought into contact with the inner side of magnet holes 31a, 41b. This allows magnetic flux of magnet 41b to smoothly enter rotor core 20 from the surface of magnet 41b facing radially outward.

The magnetic pole portion 70 in the rotor core 20 is divided into a first region 20A located radially outside the pair of magnets 41a, 41b, and a second region 20B located radially inside. The circumferential width of the first region 20A narrows as it moves radially inward. The first region 20A and the second region 20B are defined by a pair of magnet holes 31a, 31b as a boundary. The first region 20A is pushed radially outward from the first region 20A by the centrifugal force generated when the rotor 10 rotates. The first region 20A and the second region 20B are connected by a third region 20C located between the radially inner ends of the pair of magnet holes 31a, 31b.

The magnetic poles of the pair of magnets 41a, 41b are arranged along a direction perpendicular to the direction in which the magnets 41a, 41b extend when viewed in the axial direction. The magnetic pole of one magnet 41a located on the radial outside is the same as the magnetic pole of the other magnet 41b located on the radial outside.

As shown in FIG. 3, in the magnetic pole portion 70N, the magnetic pole located radially outside one magnet 41a and the magnetic pole located radially outside the other magnet 41b are north poles. Also, although not shown, in the magnetic pole portion 70S, the magnetic poles of each magnet 40 are arranged inverted with respect to the magnetic pole portion 70N. In other words, in the magnetic pole portion 70S, the magnetic pole located radially outside one magnet 41a and the magnetic pole located radially outside the other magnet 41b are south poles.

The multiple storage sections 33 are arranged radially outward from the multiple magnet holes 30. The storage sections 33 extend in a curved arc shape in the circumferential direction. When viewed in the axial direction, the storage sections 33 are arranged symmetrically with respect to the d-axis (magnetic pole center line IL1). The storage sections 33 are arranged in each of the magnetic pole sections 70. The storage sections 33 are arranged separately in the magnetic pole sections 70 adjacent to each other in the circumferential direction. The multiple storage sections 33 penetrate the rotor core 20 in the axial direction. The storage sections 33 may be connected to the magnet holes 31a. In this case, a larger load can be applied to the magnetostrictive section 50 by the centrifugal force when the rotor 10 rotates.

A number of magnetostrictive portions 50 are housed inside each of the multiple housing portions 33. The multiple magnetostrictive portions 50 are arranged in the housing portion 33 radially outside the magnetic pole portions 70 when viewed in the axial direction. Gaps 33a, 33b are provided between both circumferential ends of the magnetostrictive portions 50 and the inner surface of the housing portion 33. The gaps 33a, 33b are located between the magnetic pole portions 70 that are lined up in the circumferential direction. There are no particular limitations on the method of fixing the housing portion 33 inside the housing portion 33.

The magnetostrictive portion 50 is disposed on the magnetic pole center line IL1 of the magnetic pole portion 70, radially outside the magnet 40. The magnetostrictive portion 50 extends in a curved arc shape in the circumferential direction. That is, the magnetostrictive portion 50 is disposed on the d-axis of the magnetic pole portion 70, radially outside the two magnets 41a, 41b, and extends in the circumferential direction. The center of curvature of the curved magnetostrictive portion 50 is the central axis J.

The magnetostrictive portion 50 is provided with a dimension that covers the range in which the magnet 40 is arranged in the circumferential direction. The magnetostrictive portion 50 includes a material whose relative permeability changes with elastic deformation. The magnetostrictive portion 50 is made of, for example, an electromagnetic steel sheet with a small amount of Si. One example of the material of the magnetostrictive portion 50 is permendur. The magnetostrictive portion 50 has an easy axis of magnetization in the circumferential direction, which is the longitudinal direction, and a hard axis in the radial direction, which is perpendicular to the longitudinal direction. Therefore, the magnetostrictive portion 50 has a larger relative permeability in the circumferential direction and a smaller relative permeability in the radial direction under a tensile stress in which the tensile direction is the circumferential direction, compared to when no tensile stress acts.

By arranging the magnetostrictive portion 50 radially outward from the magnet 40, when the rotor 10 rotates at high speed, the magnetostrictive portion 50 is given a compressive stress toward the radially outward direction by the centrifugal force of the first region 20A in the rotor core 20 and the magnets 41a and 41b. As a result, the magnetostrictive portion 50 is compressed in the radial direction, reducing the radial dimension, and expands on both sides in the circumferential direction to increase the circumferential dimension. That is, the magnetostrictive portion 50 elastically deforms in the circumferential direction. The magnetostrictive portion 50 generates a tensile stress by elastically deforming in the circumferential direction. In this embodiment, gaps 33a and 33b are provided between both circumferential ends 50a and 50b of the magnetostrictive portion 50 and the inner surface of the accommodation portion 33, respectively. The amount of elastic deformation of the magnetostrictive portion 50 in the circumferential direction is shorter than the circumferential length of the gaps 33a and 33b. Therefore, the magnetostrictive portion 50 elastically deforms without being restricted by the accommodation portion 33. By applying tensile stress to the magnetostrictive portion 50, the relative permeability in the circumferential direction can be increased and the relative permeability in the radial direction can be decreased. This results in a large variable field width and maximum torque.

When the rotor 10 rotates at a low speed, the tensile stress generated in the magnetostrictive portion 50 is extremely small. On the other hand, when the rotor 10 rotates at a high speed, a large tensile stress is generated in the magnetostrictive portion 50, and the relative magnetic permeability in the radial direction in the magnetostrictive portion 50 is significantly reduced (for example, to 1/10 or less). According to this embodiment, when the rotor core 20 rotates at a low speed, the magnetic flux of the magnet passes through the magnetostrictive portion 50 and flows almost entirely to the stator 60 and interlinks with it. On the other hand, when the rotor core 20 rotates at a high speed, the excitation current of the coil 65 decreases, so that a part of the magnetic flux of the magnet leaks to the bypass path in the rotor core 20, and the magnetic flux of the magnet preferentially passes through the magnetostrictive portion 50, and the interlinkage magnetic flux to the stator 60 decreases. Since the rotation speed of the rotor 10 and the tensile stress of the magnetostrictive portion 50 are proportional to each other, the magnetic flux of the magnet interlinking with the stator 60 can be passively changed according to the rotation speed without inputting energy for the field magnet.

The magnetostrictive portion 50 is arranged symmetrically with respect to the magnetic pole center line IL1. By arranging the magnetostrictive portion 50 symmetrically with respect to the magnetic pole center line IL1, it is possible to apply a tensile stress to the magnetostrictive portion 50 in a well-balanced manner and reduce the relative permeability in the radial direction. The rotor core 20 has the first region 20A and the second region 20B, and the circumferential width of the first region 20A narrows as it moves radially inward. This makes it easier for the first region 20A to press the magnetostrictive portion 50 with centrifugal force when the rotor 10 rotates at high speed. This makes it easier to apply tensile stress to the magnetostrictive portion 50. The first region 20A and the second region 20B are bounded by the magnet holes 31a and 31b, so that the first region 20A can easily press the magnetostrictive portion 50 with centrifugal force when the rotor 10 rotates at high speed. This makes it easier to apply tensile stress to the magnetostrictive portion 50.

The magnetostrictive portion 50 is disposed within 0% to 10% of the diameter of the rotor core 20 from the outer periphery of the rotor core 20. The magnetostrictive portion 50 may have an exposed radially outer side. When the radially outer side of the magnetostrictive portion 50 is exposed, the housing portion 33 is configured as a recess recessed radially inward from the outer periphery of the rotor core 20. By disposing the magnetostrictive portion 50 within 0% to 10% of the diameter of the rotor core 20 from the outer periphery of the rotor core 20, the magnet 40 can be disposed close to the outer periphery of the rotor core 20, thereby realizing high torque.

According to the above configuration, when the rotor core 20 rotates at high speed, a tensile stress is applied to the magnetostrictive portion 50 due to the centrifugal force, which changes the relative permeability in the radial direction, eliminating the need to provide a separate device for changing the relative permeability, which contributes to miniaturization and cost reduction. According to the above configuration, by providing the magnetostrictive portion 50 to an existing rotor 10, it is possible to easily add a variable field magnet function.

In the rotor 10 of this embodiment, each magnetic pole portion 70 has two magnets 41a, 41b. The two magnets 41a, 41b are arranged at a distance from each other in the circumferential direction, and extend in a direction that separates them from each other in the circumferential direction as they move from the radially inner side to the radially outer side when viewed in the axial direction. That is, the magnetic pole portion 70 of this embodiment is provided with only two magnets 41a, 41b, which are arranged in a V-shape. When each magnetic pole portion 70 has such a configuration, it is easier to achieve high torque while increasing the variable field width of the relative magnetic permeability, compared to when the magnetic pole portion has only one magnet or when three or more magnets are arranged in a triangular shape (∇ shape). This will be explained below using Figures 4 to 6.

4 is a graph showing the variable field width and torque when the first angle α is changed in the rotor 10 of the above embodiment. Note that Fig. 4 shows the simulation results when the thickness of the magnetostrictive portion 50 is d.
FIG. 5 is a graph similar to FIG. 4, but shows the results of a simulation in which the thickness of the magnetostrictive portion 50 is set to 2d (twice that in FIG. 4).
FIG. 6 is a graph similar to FIGS. 4 and 5, but shows the results of a simulation in which the thickness of the magnetostrictive portion 50 is set to 3d (three times that in the case of FIG. 4).

In none of the graphs in Figures 4 to 6 does the torque of the rotor 10 change significantly when the first angle α is changed. On the other hand, when comparing the graphs in Figures 4 to 6, it can be seen that in all cases, the variable field width reaches its peak when the first angle α is in the range of 50° to 60°.

From this, it can be seen that with the rotor 10 of this embodiment, the torque of the rotor 10 can be stabilized regardless of the first angle α. Furthermore, by setting the first angle α within a specific range (50° or more and 60° or less), the variable field width can be increased. With the rotor 10 of this embodiment, the torque and the variable field width are not in a trade-off relationship with respect to the first angle α, and by appropriately designing the first angle α, a rotating electric machine 1 with appropriately increased torque and variable field width can be provided.

According to this embodiment, the angle (first angle α) between the two magnets 41a, 41b is set to 50° or more and 60° or less, thereby making it possible to increase the variable field width while suppressing torque reduction. In addition, by increasing the variable field width of the rotor 10, the relative permeability of the magnetostrictive portion 50 can be significantly changed during both low-speed rotation and high-speed rotation, thereby increasing the rotational efficiency of the rotor at each rotation speed and suppressing the power consumption of the rotating electric machine 1.

In this embodiment, both circumferential ends 50a, 50b of the magnetostrictive portion 50 are located circumferentially outward from the region between the radially outer ends 41aa, 41ba of the two magnets 41a, 41b. That is, the end 50a on one circumferential side (+θ side) of the magnetostrictive portion 50 is located on one circumferential side (+θ side) of the radially outer end 41aa of one magnet 41a. Also, the end 50b on the other circumferential side (-θ side) of the magnetostrictive portion 50 is located on the other circumferential side (-θ side) of the radially outer end 41ba of the other magnet 41b. According to this embodiment, most of the magnetic flux coming out from the end faces facing the radial outside of the pair of magnets 41a, 41b easily passes through the magnetostrictive portion 50. As a result, the rotor 10 is more susceptible to the effect of the change in relative permeability due to the deformation of the magnetostrictive portion 50, and the variable field width can be increased. In addition, because the entire magnetostrictive portion 50 is positioned radially outside the first region 20A, centrifugal force is more easily applied to the magnetostrictive portion 50, and the magnetostrictive portion 50 is easily elastically deformed sufficiently to change the relative permeability of the magnetostrictive portion 50.

In this embodiment, both circumferential ends 50a, 50b of the magnetostrictive portion 50 are located circumferentially inward from the region between the circumferential outer ends 41ab, 41bb of the two magnets 41a, 41b. That is, the end 50a on one circumferential side (+θ side) of the magnetostrictive portion 50 is located on the other circumferential side (-θ side) than the circumferential outer end 41ab of one magnet 41a. Also, the end 50b on the other circumferential side (-θ side) of the magnetostrictive portion 50 is located on one circumferential side (+θ side) than the circumferential outer end 41bb of the other magnet 41b. In the magnetic pole portion 70, the magnetic flux density passing circumferentially outward is sufficiently low from the region between the circumferential outer ends 41ab, 41bb of the two magnets 41a, 41b. For this reason, even if the magnetostrictive portion 50 is extended circumferentially further outward than the region between the circumferentially outer ends 41ab, 41bb of the two magnets 41a, 41b, it is difficult to contribute to the change in the characteristics of the rotor 10 according to the rotation speed. According to this embodiment, by arranging the magnetostrictive portion 50 circumferentially inward than the region between the circumferentially outer ends 41ab, 41bb of the two magnets 41a, 41b, it is possible to change the characteristics of the rotor 10 according to the rotation speed while suppressing the material cost of the magnetostrictive portion 50.

Here, the angle between the circumferential ends 50a, 50b of the magnetostrictive portion and the central axis J is defined as the second angle β. Similarly, the angle between the radially outer ends 41aa, 41ba of the two magnets 41a, 41b and the central axis J is defined as the first reference angle A1, and the angle between the circumferentially outer ends 41ab, 41bb is defined as the second reference angle A2.

In this embodiment, the magnetostrictive portion 50 is arranged symmetrically with respect to the magnetic pole center line IL1. Therefore, when the second angle β is greater than the first reference angle A1, the circumferential ends 50a, 50b of the magnetostrictive portion 50 are located circumferentially outward from the region between the radially outer ends 41aa, 41ba of the two magnets 41a, 41b. Also, when the second angle β is equal to or less than the second reference angle A2, the circumferential ends 50a, 50b of the magnetostrictive portion 50 are located circumferentially inward from the region between the circumferentially outer ends 41ab, 41bb of the two magnets 41a, 41b. The circumferential ends 50a, 50b of the magnetostrictive portion 50 of this embodiment satisfy the above-mentioned relationship (A1<β<A2), and the above-mentioned effect can be obtained.

Figure 7 is a graph showing the variable field width when the second angle β is changed in the rotor 10 of the above embodiment. As shown in Figure 7, in the rotor 10 of this embodiment, it can be seen that the variable field width peaks when the second angle β is around 20°. In addition, for reference, a line of 20° centered on the central axis J is drawn in Figure 3 so as to be linearly symmetrical with the magnetic pole center line IL1. The simulation results shown in Figure 7 also confirmed the advantage of setting the second angle β to the first reference angle A1 or more. In addition, the simulation results shown in Figure 7 show that there is no improvement in the variable field width even if the second angle β is increased beyond 20°. From this, it was confirmed that the variable field width can be sufficiently increased even if the second angle β is made smaller than the second reference angle A2 to save on material costs.

Although the preferred embodiment of the present invention has been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to the examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

The rotating electric machine to which the present invention is applied is not limited to a motor, and may be a generator. In this case, the rotating electric machine may be a three-phase AC generator. The use of the rotating electric machine is not particularly limited. The rotating electric machine may be mounted, for example, on a vehicle, or on equipment other than a vehicle. The number of poles and the number of slots of the rotating electric machine are not particularly limited. The coils in the rotating electric machine may be configured in any winding method. The configurations described above in this specification can be combined as appropriate within a range that does not contradict each other.

The present technology can be configured as follows.
(1) A rotor comprising: a rotor core having a plurality of magnet holes and a plurality of accommodating portions extending in the axial direction around a central axis; a plurality of magnetic pole portions having magnets arranged in the magnet holes; and a magnetostrictive portion arranged in the accommodating portion, the relative magnetic permeability of which changes with elastic deformation, wherein each of the magnetic pole portions has two magnets, the two magnets being arranged at a distance from each other in the circumferential direction and extending in a direction separating them from each other in the circumferential direction as viewed in the axial direction from the radially inner side to the radially outer side, and the magnetostrictive portion being arranged on the d-axis of the magnetic pole portions, radially outside the two magnets, and extending in the circumferential direction.
(2) The rotor according to (1), wherein the angle between the two magnets is equal to or greater than 50° and equal to or less than 60°.
(3) The rotor according to (1) or (2), in which both circumferential ends of the magnetostrictive portion are located circumferentially outward of a region between radially outer ends of the two magnets.
(4) The rotor according to (3), in which both circumferential ends of the magnetostrictive portion are located circumferentially inward of a region between circumferentially outer ends of the two magnets.
(5) The rotor according to any one of (1) to (4), wherein a gap is provided between each of both circumferential ends of the magnetostrictive portion and an inner surface of the housing portion.
(6) The rotor according to any one of (1) to (5), wherein the magnetostrictive portion elastically deforms in a circumferential direction due to centrifugal force generated by rotation of the rotor core.
(7) The rotor according to any one of (1) to (6), wherein the two magnets and the magnetostrictive portion are arranged line-symmetrically with respect to the d-axis.
(8) The rotor according to any one of (1) to (7), wherein a gap is provided between an inner side surface of the magnet hole and a radially inner side surface of the magnet.
(9) The rotor according to any one of (1) to (8), wherein the magnetostrictive portion extends in a curved manner in the circumferential direction.
(10) The rotor according to (9), wherein the magnetostrictive portion is disposed within a range of 0% to 10% of a diameter of the rotor core from an outer periphery of the rotor core.
(11) A rotating electric machine comprising: a rotor according to any one of (1) to (10); and a stator opposed to the rotor.

1... rotating electric machine, 10... rotor, 20... rotor core, 30, 31a, 31b... magnet hole, 33... storage section, 33a, 33b, S1... gap, 40, 41a, 41b... magnet, 41aa, 41ab, 41ba, 41bb, 50a, 50b... end, 50... magnetostrictive section, 60... stator, 70, 70N, 70S... magnetic pole section, J... central axis, α... first angle, β... second angle, A1... first reference angle, A2... second reference angle

Claims (11)

a rotor core having a plurality of magnet holes and a plurality of housing portions extending in an axial direction around a central axis;
a plurality of magnetic pole portions each having a magnet disposed in the magnet hole;
A magnetostrictive portion is disposed in the housing portion, and the relative permeability of the magnetostrictive portion changes with elastic deformation.
One of the magnetic pole portions has two magnets,
The two magnets are arranged at an interval from each other in the circumferential direction, and extend in a direction that separates from each other in the circumferential direction from the radially inner side toward the radially outer side as viewed in the axial direction,
The magnetostrictive portion is disposed on the d-axis of the magnetic pole portion radially outside the two magnets and extends in the circumferential direction.
Rotor. The angle between the two magnets is greater than or equal to 50° and less than or equal to 60°.
The rotor of claim 1 . Both circumferential ends of the magnetostrictive portion are located circumferentially outward of a region between radially outer ends of the two magnets.
The rotor of claim 1 . Both circumferential end portions of the magnetostrictive portion are located circumferentially inward of a region between the circumferentially outer ends of the two magnets.
A rotor as claimed in claim 3. A gap is provided between each of the circumferential ends of the magnetostrictive portion and an inner surface of the accommodation portion.
The rotor of claim 1 . The magnetostrictive portion elastically deforms in a circumferential direction due to centrifugal force generated by rotation of the rotor core.
The rotor of claim 1 . The two magnets and the magnetostrictive portion are arranged line-symmetrically with respect to the d-axis.
The rotor of claim 1 . A gap is provided between the inner surface of the magnet hole and the radially inner side surface of the magnet.
The rotor of claim 1 . The magnetostrictive portion extends in a curved manner in the circumferential direction.
The rotor of claim 1 . The magnetostrictive portion is disposed within a range of 0% to 10% of a diameter of the rotor core from an outer periphery of the rotor core.
A rotor according to claim 9. A rotor according to any one of claims 1 to 10;
a stator facing the rotor;
A rotating electric machine comprising:

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