WO2023171488A1

WO2023171488A1 - Rotor and rotating electric machine

Info

Publication number: WO2023171488A1
Application number: PCT/JP2023/007545
Authority: WO
Inventors: 智数福▲崎▼; 瑞娟郭
Original assignee: ニデック株式会社
Priority date: 2022-03-09
Filing date: 2023-03-01
Publication date: 2023-09-14

Abstract

One aspect of a rotor of the present invention comprises: a rotor core having a plurality of magnet holes extending axially about a central axis, and a plurality of storage parts; a plurality of magnetic pole parts having magnets disposed in the magnet holes; and a magnetostrictive part that is disposed in the storage part with a gap between the magnetic pole parts, and has a relative magnetic permeability which varies with elastic deformation. The magnetostrictive part is disposed on the d-axis of the magnetic pole part on a radially outer side of the magnets, and extends in a circumferential direction.

Description

Rotor and rotating electrical machine

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

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

Patent Document 1 discloses a magnetic flux short circuit that is arranged in a plurality of flux barriers formed between adjacent magnet insertion holes and has a magnetic flux path from one first pole of the adjacent permanent magnet to the other second pole. Disclosed is a rotor core comprising a magnetic flux shorting member, at least a portion of which is made of a giant magnetostrictive material. In the rotor core described in Patent Document 1, when the rotor rotates at high speed, the magnetic permeability of the giant magnetostrictive material is improved compared to when the rotor rotates at low speed, thereby increasing the short-circuit magnetic flux.

Japanese Publication No. 2004-343842

Considering the average efficiency of the motor, when the rotor rotates at high speed, it is preferable to reduce the radial magnetic permeability of the rotor to reduce the magnet magnetic flux. However, in the rotor core described in Patent Document 1, the rotor Magnetic permeability increases when rotating at high speed. Therefore, the effect on improving the average efficiency of the motor and the system efficiency is small. Further, the rotor core described in Patent Document 1 is provided with a weight and a compression spring in order to change the magnetic permeability, which results in an increase in size and cost.

The present invention has been made in consideration of the above points, and one of the objects of the present invention is to provide a rotor and a rotating electrical machine that can improve efficiency with a simple configuration.

One aspect of the rotor of the present invention includes: a rotor core provided with a plurality of magnet holes and a plurality of accommodating parts extending in the axial direction around a central axis; a plurality of magnetic pole parts having magnets arranged in the magnet holes; a magnetostrictive part that is arranged in the housing part with a gap between the magnetic pole parts and whose relative magnetic permeability changes with elastic deformation, the magnetostrictive part being arranged on the radially outer side of the magnet, It is arranged on the d-axis in the section and extends in the circumferential direction.

One aspect of the rotating electric machine of the present invention includes the above rotor and a stator facing the rotor.

According to one aspect of the present invention, efficiency can be increased in a rotor and a rotating electric machine with a simple configuration.

FIG. 1 is a sectional view showing a rotating electric machine having a rotor according to the present embodiment. FIG. 2 is a sectional view showing a part of the rotating electric machine having the rotor of the first embodiment, and is a sectional view taken along line II-II in FIG. FIG. 3 is a sectional view showing a part of the magnetic pole part and stator core of the rotor according to the first embodiment. FIG. 4 is a sectional view showing a part of the magnetic pole part and stator core of the rotor according to the second embodiment. FIG. 5 is a sectional view showing a part of the magnetic pole part and stator core of the rotor according to the third embodiment.

Hereinafter, a rotor and a rotating electric machine according to embodiments of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments, and can be arbitrarily modified within the scope of the technical idea of the present invention. Further, in the following drawings, in order to make each structure easier to understand, the scale, number, etc. of each structure may be different from the actual structure.

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 a virtual line that is parallel to the Z-axis direction and extends in the vertical direction. In the following explanation, 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." Arrows θ appropriately shown in each figure indicate the circumferential direction. The arrow θ is oriented clockwise around the central axis J when viewed from above. In the following explanation, the side in the circumferential direction where the arrow θ is directed with a certain object as a reference, that is, the side that proceeds clockwise when viewed from above, will be referred to as "one side in the circumferential direction", and the side in the circumferential direction with a certain object as a reference The side opposite to the side toward which the arrow θ is directed, that is, the side that proceeds counterclockwise when viewed from above, is called the "other side in the circumferential direction."

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.

[Rotating electrical machine]
As shown in FIG. 1, the rotating electrical machine 1 is an inner rotor type rotating electrical machine.
In this embodiment, the rotating electrical machine 1 is a three-phase AC rotating electrical machine. The rotating electric machine 1 is, for example, a three-phase motor that is driven by being supplied with three-phase AC power. 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 accommodates the rotor 10, stator 60, bearing holder 4, and

bearings

5a and 5b inside. 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 60 is located on the outside of the rotor 10 in the radial direction. Stator 60 includes a stator core 61, an insulator 64, and a plurality of coils 65. Stator core 61 has a core back 62 and a plurality of teeth 63. The core back 62 is located on the radially outer side of the rotor core 20, which will be described later. Note that in FIGS. 2 to 3 below, illustration of the coil 65 is omitted. In FIGS. 2 and 3, illustration of the insulator 64 is omitted.

As shown in FIG. 2, the core back 62 has an annular shape surrounding the rotor core 20. The core back 62 has, for example, an annular shape centered on the central axis J.

The plurality of teeth 63 extend radially inward from the core back 62. The plurality of teeth 63 are arranged side by side at intervals in the circumferential direction. For example, the plurality of teeth 63 are arranged at equal intervals all around the circumferential direction. For example, 48 teeth 63 are provided. That is, the number of slots 67 in the rotating electric machine 1 is, for example, 48. As shown in FIG. 3, each of the plurality of teeth 63 has a base portion 63a and an umbrella portion 63b.

The base 63a extends radially inward from the core back 62. The circumferential dimension of the base portion 63a is, for example, the same throughout the radial direction. Note that the circumferential dimension of the base portion 63a may become smaller toward the inside in the radial direction, for example.

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

The plurality of coils 65 are attached to the stator core 61. As shown in FIG. 1, the plurality of coils 65 are attached to the teeth 63 via an insulator 64, for example. In this embodiment, the coil 65 is wound in a distributed manner. In other words, each coil 65 is wound across a plurality of teeth 63. In this embodiment, the coil 65 is fully 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 that occurs when the stator 60 is supplied with three-phase AC power. The number of poles of the rotating electric machine 1 is, for example, eight. That is, the rotating electrical machine 1 is, for example, a rotating electrical machine with 8 poles and 48 slots. Thus, in the rotating electric machine 1 of this embodiment, when the number of poles is N, the number of slots is N×6.

[First embodiment of rotor 10]
The rotor 10 is rotatable around a central axis J. As shown in FIG. 2, the rotor 10 includes a shaft 11, a rotor core 20, a plurality of magnets 40, and a plurality of magnetostrictive sections 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.

The rotor core 20 is a magnetic material. 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 is passed through the through hole 21 . The shaft 11 is fixed within the through hole 21 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 rotor core 20 has a plurality of magnet holes 30 and a plurality of accommodating portions 33. For example, the plurality of magnet holes 30 penetrate the rotor core 20 in the axial direction. A plurality of magnets 40 are accommodated inside the plurality of magnet holes 30, respectively. The method of fixing the magnet 40 within the magnet hole 30 is not particularly limited. The plurality of magnet holes 30 include a pair of first magnet holes 31 a and 31 b and a second magnet hole 32 .

The types of the plurality of magnets 40 are not particularly limited. The magnet 40 may be, for example, a neodymium magnet or a ferrite magnet. The plurality of magnets 40 include a pair of

first magnets

41a and 41b and a second magnet 42. The pair of

first magnets

41a and 41b and the second magnet 42 constitute poles.

In this embodiment, a plurality of the pair of

first magnet holes

31a, 31b, the pair of

first magnets

41a, 41b, the second magnet hole 32, and the second magnet 42 are provided at intervals in the circumferential direction. The pair of

first magnet holes

31a, 31b, the pair of

first magnets

41a, 41b, the second magnet hole 32, and the second magnet 42 are provided, for example, eight each.

The rotor 10 has a plurality of magnetic pole parts 70 each including a pair of

first magnet holes

31a, 31b, a pair of

first magnets

41a, 41b, a second magnet hole 32, and a second magnet 42. For example, eight magnetic pole parts 70 are provided. For example, the plurality of magnetic pole parts 70 are arranged at equal intervals all around the circumferential direction. The plurality of magnetic pole parts 70 include a plurality of magnetic pole parts 70N whose magnetic poles on the outer circumferential surface of the rotor core 20 are north poles, and a plurality of magnetic pole parts 70S whose magnetic poles on the outer circumferential surface of the rotor core 20 are south poles. For example, four magnetic pole parts 70N and four magnetic pole parts 70S are provided. The four magnetic pole parts 70N and the four magnetic pole parts 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 positions in the circumferential direction are different.

As shown in FIG. 3, in the magnetic pole part 70, the pair of

first magnet holes

31a, 31b are arranged at intervals from each other in the circumferential direction. The first magnet hole 31a is located, for example, on one circumferential side (+θ side) of the first magnet hole 31b. For example, the

first magnet holes

31a and 31b extend substantially linearly in a direction oblique to the radial direction when viewed in the axial direction. The pair of

first magnet holes

31a, 31b extend in a direction that separates from each other in the circumferential direction from the radially inner side toward the radially outer side when viewed in the axial direction. That is, the circumferential distance between the first magnet hole 31a and the first magnet hole 31b increases from the radially inner side to the radially outer side. The first magnet hole 31a is located, for example, on one side in the circumferential direction from the inside in the radial direction to the outside in the radial direction. The first magnet hole 31b is located, for example, on the other circumferential side (−θ side) from the radially inner side toward the radially outer side. The radially outer ends of the first magnet holes 31 a and 31 b are located at the radially outer peripheral edge of the rotor core 20 .

The first magnet hole 31a and the first magnet hole 31b are, for example, arranged to sandwich the magnetic pole center line IL1 shown in FIG. 3, which constitutes the d-axis, in the circumferential direction when viewed in the axial direction. 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. The first magnet hole 31a and the first magnet hole 31b are, for example, arranged symmetrically with respect to the magnetic pole center line IL1 when viewed in the axial direction. Hereinafter, a description of the first magnet hole 31b may be omitted as the structure is similar to the first magnet hole 31a except that it is axisymmetric with respect to the magnetic pole center line IL1.

The first magnet hole 31a has a first straight portion 31c, an inner end 31d, and an outer end 31e. The first straight portion 31c extends linearly in the direction in which the first magnet hole 31a extends when viewed in the axial direction. The first straight portion 31c has, for example, a rectangular shape when viewed in the axial direction. The inner end portion 31d is connected to the radially inner end portion of the first straight portion 31c. The inner end 31d is a radially inner end of the first magnet hole 31a. The outer end portion 31e is connected to the radially outer end of the first straight portion 31c. The outer end 31e is a radially outer end of the first magnet hole 31a. The outer end portion 31e extends radially outward from the radially outer end of the first straight portion 31c along the magnetic pole center line IL1 (details will be described later). The first magnet hole 31b has a first straight portion 31f, an inner end 31g, and an outer end 31h.

The second magnet hole 32 is located between the radially outer ends of the pair of

first magnet holes

31a and 31b in the circumferential direction. That is, in this embodiment, the second magnet hole 32 is located between the outer end portion 31e and the outer end portion 31h in the circumferential direction. For example, the second magnet hole 32 extends substantially linearly in a direction orthogonal to the radial direction when viewed in the axial direction. The second magnet hole 32 extends, for example, in a direction perpendicular to the magnetic pole center line IL1 when viewed in the axial direction. The pair of

first magnet holes

31a, 31b and the second magnet hole 32 are arranged, for example, along a ∇ shape when viewed in the axial direction.

Note that in this specification, "a certain object extends in a direction perpendicular to a certain direction" means that a certain object extends in a direction strictly orthogonal to a certain direction; This also includes cases in which it extends in a direction substantially orthogonal to a certain direction. "A direction substantially perpendicular to a certain direction" includes, for example, a direction that is tilted within a range of several degrees [°] with respect to a direction strictly perpendicular to a certain direction, due to manufacturing tolerances or the like.

When viewed in the axial direction, for example, the magnetic pole center line IL1 passes through the circumferential center of the second magnet hole 32. That is, the circumferential position of the circumferential center of the second magnet hole 32 coincides with the circumferential position of the circumferential center of the magnetic pole portion 70, for example. The shape of the second magnet hole 32 when viewed in the axial direction is, for example, a line-symmetrical shape centered on the magnetic pole center line IL1. The second magnet hole 32 is located at the radially outer peripheral edge of the rotor core 20 .

The second magnet hole 32 has a second straight portion 32a, one end 32b, and the other end 32c. The second straight portion 32a extends linearly in the direction in which the second magnet hole 32 extends when viewed in the axial direction. The second straight portion 32a has, for example, a rectangular shape when viewed in the axial direction. The one end portion 32b is connected to the end portion of the second straight portion 32a on one circumferential side (+θ side). One end portion 32b is an end portion of the second magnet hole 32 on one side in the circumferential direction. The one end portion 32b is disposed at a distance from the outer end portion 31e of the first magnet hole 31a on the other circumferential side (−θ side). The other end portion 32c is connected to the end portion of the second straight portion 32a on the other side (−θ side) in the circumferential direction. The other end 32c is the other end of the second magnet hole 32 in the circumferential direction. The other end 32c is spaced apart from the outer end 31h of the first magnet hole 31b on one side in the circumferential direction.

The pair of

first magnets

41a and 41b are housed inside the pair of

first magnet holes

31a and 31b, respectively. The first magnet 41a is housed inside the first magnet hole 31a. The first magnet 41b is housed inside the first magnet hole 31b. The pair of

first magnets

41a and 41b have, for example, a rectangular shape when viewed in the axial direction. The lengths in the extending direction of the pair of

first magnets

41a and 41b are the same. The lengths of the

first magnets

41a, 41b in the direction orthogonal to the direction in which the pair of

first magnets

41a, 41b extend are the same.

Although not shown, the

first magnets

41a and 41b have, for example, a rectangular parallelepiped shape. Although not shown, the

first magnets

41a and 41b are provided, for example, throughout the

first magnet holes

31a and 31b in the axial direction. The pair of

first magnets

41a and 41b are spaced apart from each other in the circumferential direction. The first magnet 41a is located, for example, on one circumferential side (+θ side) of the first magnet 41b.

The first magnet 41a extends along the first magnet hole 31a when viewed in the axial direction. The first magnet 41b extends along the first magnet hole 31b when viewed in the axial direction. For example, the

first magnets

41a and 41b extend substantially linearly in a direction oblique to the radial direction when viewed in the axial direction. The pair of

first magnets

41a and 41b extend in a direction that separates from each other in the circumferential direction from the radially inner side toward the radially outer side when viewed in the axial direction. That is, the circumferential distance between the first magnet 41a and the first magnet 41b increases from the radially inner side to the radially outer side.

The first magnet 41a is located, for example, on one circumferential side (+θ side) from the radially inner side to the radially outer side. The first magnet 41b is located, for example, on the other circumferential side (-θ side) from the radially inner side to the radially outer side. The first magnet 41a and the first magnet 41b are, for example, arranged to sandwich the magnetic pole center line IL1 in the circumferential direction when viewed in the axial direction. The first magnet 41a and the first magnet 41b are arranged symmetrically with respect to the magnetic pole center line IL1, for example, when viewed in the axial direction. Hereinafter, a description of the first magnet 41b may be omitted for the same configuration as the first magnet 41a except that it is line symmetrical with respect to the magnetic pole center line IL1.

The first magnet 41a is fitted into the first magnet hole 31a. More specifically, the first magnet 41a is fitted within the first straight portion 31c. Among the side surfaces of the first magnet 41a, at least the radially inner side surface of both side surfaces in the direction orthogonal to the direction in which the first straight portion 31c extends has a gap between it and the inner surface of the first straight portion 31c. It has a slit S1. The first magnet 41a has a slit S1 between the radially inner side surface and the inner side surface of the first straight portion 31c, so that the diameter of the first magnet 41a is increased by centrifugal force when the rotor 10 rotates, as shown in FIG. The radially outer side surface contacts the inner side of the first straight portion 31c while the inner side surface in the radial direction is separated from the inner surface of the first straight portion 31c. The first magnet 41a is configured to be in contact with the inner surface of the first linear portion 31c when not rotating, and a slit S1 is provided between the first magnet 41a and the inner surface of the first linear portion 31c due to centrifugal force when the rotor 10 rotates. It's okay.

By providing the slit S1, the magnetic pole portion 70 in the rotor core 20 is divided into a first region 20A located on the radially outer side of the

first magnets

41a and 41b, and a second region 20B located on the radially outer side. The width of the first region 20A in the circumferential direction becomes narrower toward the inner side in the radial direction. A boundary between the first region 20A and the second region 20B is formed by slits S1 and S2. The angle formed by the boundary formed by the slits S1 and S2 is larger than the angle occupied by the magnetic pole portion 70 on the rotor core 20.

Therefore, the first region 20A pushes a location radially outward from the first region 20A due to centrifugal force when the rotor 10 rotates. The first region 20A and the second region 20B are connected at a third region 20C located between the radially inner ends of the

first magnets

41a and 41b. In the direction in which the first straight portion 31c extends when viewed in the axial direction, the length of the first magnet 41a is, for example, the same as the length of the first straight portion 31c.

When viewed in the axial direction, both ends of the first magnet 41a in the stretching direction are arranged apart from both ends of the first magnet hole 31a in the stretching direction. When viewed in the axial direction, an inner end 31d and an outer end 31e are arranged adjacent to each other on both sides of the first magnet 41a in the direction in which the first magnet 41a extends. Here, in this embodiment, the inner end portion 31d constitutes the first flux barrier portion 51a. The outer end portion 31e constitutes a first flux barrier portion 51b. In other words, the rotor core 20 has a pair of first

flux barrier parts

51a and 51b arranged with the first magnet 41a in between in the direction in which the first magnet 41a extends when viewed in the axial direction. The rotor core 20 includes a pair of first

flux barrier portions

51c and 51d arranged with the first magnet 41b in between in the direction in which the first magnet 41b extends when viewed in the axial direction.

The first flux barrier portion 51b located on the radially outer side extends radially outward from the radial end of the first magnet 41a in parallel to the magnetic pole center line IL1. The first flux barrier portion 51d located on the radially outer side extends radially outward from the radial end of the first magnet 41b in parallel with the magnetic pole center line IL1.

As described above, the rotor core 20 includes first

flux barrier portions

51a and 51b arranged in pairs with each of the

first magnets

41a and 41b sandwiched therebetween in the direction in which the

first magnets

41a and 41b extend when viewed in the axial direction. , 51c, and 51d. The first

flux barrier parts

51a, 51b, 51c, and 51d and the second

flux barrier parts

52a and 52b, which will be described later, are parts that can suppress the flow of magnetic flux. That is, it is difficult for magnetic flux to pass through each flux barrier portion. Each flux barrier section is not particularly limited as long as it can suppress the flow of magnetic flux, and may include a gap section or a non-magnetic section such as a resin section.

The second magnet 42 is housed inside the second magnet hole 32. The second magnet 42 is disposed at a position in the circumferential direction between the pair of

first magnets

41a, 41b on the radially outer side than the radially inner end portions of the pair of

first magnets

41a, 41b. The second magnet 42 extends along the second magnet hole 32 when viewed in the axial direction. The second magnet 42 extends in a direction perpendicular to the radial direction when viewed in the axial direction. The pair of

first magnets

41a, 41b and second magnet 42 are arranged, for example, along a ∇ shape when viewed in the axial direction.

Note that in this specification, "the second magnet is disposed at a position in the circumferential direction between the pair of first magnets" means that the position in the circumferential direction of the second magnet is located at the position in the circumferential direction between the pair of first magnets. The radial position of the second magnet with respect to the first magnet is not particularly limited as long as it is included in the directional position.

The shape of the second magnet 42 when viewed in the axial direction is, for example, a shape that is axisymmetric with respect to the magnetic pole center line IL1. The second magnet 42 has, for example, a rectangular shape when viewed in the axial direction. When viewed in the axial direction, the length of the second magnet 42 in the radial direction is shorter than the length of the

first magnets

41a, 41b in the direction orthogonal to the direction in which the

first magnets

41a, 41b extend. By making the length of the second magnet 42 in the radial direction shorter and thinner than the length of the

first magnets

41a, 41b in the direction orthogonal to the direction in which the

first magnets

41a, 41b extend, the weight of the second magnet 42 can be reduced. The weight can be made smaller than the weight of the

first magnets

41a and 41b. By reducing the weight of the second magnet 42, the centrifugal force of the second magnet 42 during rotation of the rotor 10 can be reduced. Therefore, the load on the rotor core 20 can be reduced.

By making the second magnet 42 thinner, the second magnet 42 can be placed outside the rotor core 20 in the radial direction. By arranging the second magnet 42 outside the rotor core 20 in the radial direction, it is possible to increase the output of the rotating electric machine 1. Since the magnetization of the second magnet 42 is strengthened by the

first magnets

41a and 41b, it is possible to increase the strength of the rotor core 20 and the output of the rotating electric machine 1 without impairing the demagnetization resistance. Furthermore, high demagnetization resistance can be obtained with a small amount of magnets.

Although not shown, the second magnet 42 has a rectangular parallelepiped shape, for example. Although not shown, the second magnet 42 is provided, for example, throughout the second magnet hole 32 in the axial direction. The radially inner portion of the second magnet 42 is located, for example, between the radially outer ends of the pair of

first magnets

41a, 41b in the circumferential direction. The radially outer portion of the second magnet 42 is located, for example, radially outer than the pair of

first magnets

41a, 41b.

The second magnet 42 is fitted into the second magnet hole 32. More specifically, the second magnet 42 is fitted within the second straight portion 32a. Among the side surfaces of the second magnet 42, both side surfaces in the radial direction perpendicular to the direction in which the second linear portion 32a extends are in contact with, for example, the inner surface of the second linear portion 32a, respectively. The second magnet 42 may have a slit between the radially inner side surface and the inner surface of the second linear portion 32a among both side surfaces in the radial direction perpendicular to the direction in which the second linear portion 32a extends. . In the direction in which the second straight portion 32a extends when viewed in the axial direction, the length of the second magnet 42 is, for example, the same as the length of the second straight portion 32a.

When viewed in the axial direction, both ends of the second magnet 42 in the extending direction are spaced apart from both ends of the second magnet hole 32 in the extending direction. When viewed in the axial direction, one end 32b and the other end 32c are arranged adjacent to each other on both sides of the second magnet 42 in the direction in which the second magnet 42 extends. Here, in this embodiment, the one end portion 32b constitutes the second flux barrier portion 52a. The other end portion 32c constitutes a second flux barrier portion 52b. In other words, the rotor core 20 includes a pair of second

flux barrier parts

52a and 52b that are arranged to sandwich the second magnet 42 in the direction in which the second magnet 42 extends when viewed in the axial direction.

The second

flux barrier portions

52a and 52b each have an arcuate shape that extends from the circumferential end of the second magnet 42 toward the side away from the second magnet 42 in the circumferential direction and toward the inner side in the radial direction. When the second

flux barrier parts

52a, 52b extend radially outward, the distance between the second

flux barrier parts

52a, 52b and the outer peripheral surface of the rotor core 20 becomes shorter, and the load on the rotor core 20 is reduced due to centrifugal force during rotation. It has the potential to become larger. By extending the second

flux barrier portions

52a and 52b radially inward, the load on the rotor core 20 can be reduced. By forming the second

flux barrier portions

52a, 52b in an arcuate shape, stress concentration at the intersection between the circumferentially extending portion and the radially extending portion can be alleviated, thereby further reducing the load on the rotor core 20.

The pair of second

flux barrier parts

52a, 52b and the second magnet 42 are composed of a first flux barrier part 51b located on the radially outer side of the pair of first

flux barrier parts

51a, 51b sandwiching the first magnet 41a, and a first flux barrier part 51b located on the outside in the radial direction. It is located between the first flux barrier part 51d, which is located on the radially outer side of the pair of first

flux barrier parts

51c and 51d sandwiching the first magnet 41b, and the first flux barrier part 51d in the circumferential direction.

The magnetic poles of the first magnet 41a are arranged along a direction perpendicular to the direction in which the first magnet 41a extends when viewed in the axial direction. The magnetic poles of the first magnet 41b are arranged along a direction perpendicular to the direction in which the first magnet 41b extends when viewed in the axial direction. The magnetic poles of the second magnet 42 are arranged along the radial direction.

Among the magnetic poles of the first magnet 41a, the magnetic poles located on the outside in the radial direction, among the magnetic poles of the first magnet 41b, the magnetic poles located on the outside in the radial direction, and among the magnetic poles of the second magnet 42, the magnetic poles located on the outside in the radial direction are as follows: are the same as each other. Among the magnetic poles of the first magnet 41a, the magnetic poles located on the inside in the radial direction, among the magnetic poles of the first magnet 41b, the magnetic poles located on the inside in the radial direction, and among the magnetic poles of the second magnet 42, the magnetic poles located on the inside in the radial direction are as follows: are the same as each other.

As shown in FIG. 3, in the magnetic pole portion 70N, the magnetic pole of the first magnet 41a that is located on the radially outer side, the magnetic pole of the first magnet 41b that is located on the radially outer side, and the magnetic pole of the second magnet 42. The magnetic pole located on the outer side in the radial direction is, for example, an N pole. In the magnetic pole portion 70N, one of the magnetic poles of the first magnet 41a is located on the radially inner side, one of the magnetic poles of the first magnet 41b is located on the radially inner side, and one of the magnetic poles of the second magnet 42 is located on the inner side in the radial direction. The magnetic pole is, for example, the S pole.

Although not shown, in the magnetic pole part 70S, the magnetic poles of each magnet 40 are arranged inverted with respect to the magnetic pole part 70N. That is, in the magnetic pole part 70S, among the magnetic poles of the first magnet 41a, the magnetic pole located on the radially outer side, among the magnetic poles of the first magnet 41b, the magnetic pole located on the radially outer side, and among the magnetic poles of the second magnet 42, the magnetic pole is located on the radially outer side. The magnetic pole located at is, for example, the S pole. In the magnetic pole portion 70S, one of the magnetic poles of the first magnet 41a is located on the radially inner side, one of the magnetic poles of the first magnet 41b is located on the radially inner side, and one of the magnetic poles of the second magnet 42 is located on the inner side in the radial direction. The magnetic pole is, for example, the N pole.

The plurality of accommodating portions 33 are arranged radially outward from the plurality of magnet holes 30. The accommodating portion 33 extends in an arcuate manner in the circumferential direction. Viewed in the axial direction, the accommodating portion 33 is arranged symmetrically with respect to the magnetic pole center line IL1. The housing portion 33 is arranged in each of the magnetic pole portions 70 . The accommodating parts 33 in the circumferentially adjacent magnetic pole parts 70 are arranged apart from each other. For example, the plurality of accommodating portions 33 penetrate the rotor core 20 in the axial direction.

The housing portion 33 is connected to the first

flux barrier portions

51b and 51d. Since the accommodating portion 33 is connected to the first

flux barrier portions

51b and 51d, the first region 20A in the rotor core 20 is connected to the second region 20B only through the third region 20C.
Thereby, a larger load can be applied to the magnetostrictive portion 50 due to centrifugal force when the rotor 10 rotates.

A plurality of magnetostrictive sections 50 are accommodated inside the plurality of accommodating sections 33, respectively. The plurality of magnetostrictive parts 50 are arranged in the housing part 33 with

gaps

33a and 33b between the magnetic pole parts 70 when viewed in the axial direction. The method of fixing the housing section 33 within the housing section 33 is not particularly limited.

The magnetostrictive portion 50 is arranged on the magnetic pole center line IL1 of the magnetic pole portion 70 on the outside in the radial direction of the magnet 40. The magnetostrictive portion 50 extends in an arcuate manner in the circumferential direction. The magnetostrictive portion 50 is provided with a dimension that spans the range in which the magnet 40 is arranged in the circumferential direction. The magnetostrictive portion 50 includes a material whose relative magnetic permeability changes with elastic deformation. The magnetostrictive portion 50 is made of, for example, an electromagnetic steel plate with a small amount of Si. The material of the magnetostrictive portion 50 is, for example, permendur. In the magnetostrictive portion 50, the axis of easy magnetization is the circumferential direction, which is the longitudinal direction, and the axis of difficult magnetization is the radial direction, which is perpendicular to the longitudinal direction. Therefore, in the magnetostrictive portion 50, the relative magnetic permeability in the circumferential direction becomes larger and the relative magnetic permeability in the radial direction becomes smaller under a tensile stress whose tensile direction is the circumferential direction, compared to when no tensile stress is applied.

By disposing the magnetostrictive section 50 on the radially outer side of the magnet 40, when the rotor 10 rotates at high speed, the magnetostrictive section 50 is arranged in the first region 20A, the

first magnets

41a, 41b, and the second magnet 42 in the rotor core 20. is pushed radially outward by centrifugal force. Thereby, the magnetostrictive portion 50 is elastically deformed in the circumferential direction. The magnetostrictive portion 50 generates tensile stress by elastically deforming in the circumferential direction. The circumferential elastic deformation amount of the magnetostrictive portion 50 is shorter than the circumferential length of the

gaps

33a and 33b. Therefore, the magnetostrictive portion 50 is elastically deformed without being restricted in the housing portion 33. By applying tensile stress to the magnetostrictive portion 50, the relative magnetic permeability in the circumferential direction can be increased, and the relative magnetic permeability in the radial direction can be decreased. This provides a large variable field width and maximum torque.

For example, when the rotor core 20 with a magnetic permeability of 5000 μ is rotated at a low speed and the tensile stress of the magnetostrictive portion 50 is 0 MPa, the relative magnetic permeability μr (per) in the radial direction of the magnetostrictive portion 50 is 5000. On the other hand, when the rotor core 20 rotates at high speed and the tensile stress of the magnetostrictive portion 50 is 50 MPa, the relative magnetic permeability μr (per) in the radial direction of the magnetostrictive portion 50 is approximately 100. That is, according to the above configuration, the relative magnetic permeability in the radial direction can be reduced to 1/10 or less. Furthermore, when the rotor core 20 rotates at a high speed of, for example, 15,000 rpm, the relative magnetic permeability μr (per) in the radial direction of the magnetostrictive portion 50 is approximately 200.

Therefore, when the rotor core 20 rotates at a low speed, the magnetic flux of the magnet passes through the magnetostrictive portion 50 and almost flows to the stator 60 and interlinks therewith. On the other hand, when the rotor core 20 rotates at high speed, the excitation current of the coil 65 decreases, so a part of the magnetic flux leaks to the bypass path in the rotor core 20, and the magnetic flux preferentially passes through the magnetostrictive section 50. The magnetic flux linkage to the stator 60 decreases. Since the rotational speed of the rotor 10 and the tensile stress of the magnetostrictive portion 50 are in a proportional relationship, the magnetic flux of the magnet interlinking with the stator 60 can be passively varied according to the rotational speed without inputting energy for a magnetic field.

The magnetostrictive portion 50 is arranged symmetrically with respect to the magnetic pole center line IL1. By arranging the magnetostrictive portion 50 line-symmetrically with respect to the magnetic pole center line IL1, it is possible to apply tensile stress to the magnetostrictive portion 50 in a well-balanced manner, thereby reducing the relative magnetic permeability in the radial direction. The rotor core 20 has a first region 20A and a second region 20B, and the circumferential width of the first region 20A narrows toward the inside in the radial direction, so that when the rotor 10 rotates at high speed, the first region 20A becomes easier to push the magnetostrictive section 50 by centrifugal force. This makes it easier to apply tensile stress to the magnetostrictive portion 50. Since the first region 20A and the second region 20B are bounded by the slits S1 and S2, the first region 20A can easily push the magnetostrictive section 50 by centrifugal force when the rotor 10 rotates at high speed. . This makes it easier to apply tensile stress to the magnetostrictive portion 50. Since the angle formed by the boundary is larger than the angle occupied by the magnetic pole part 70 on the rotor core 20, the first region 20A can easily push the magnetostrictive part 50 by 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% or more and within 10% of the diameter of the rotor core 20 from the outer periphery of the rotor core 20. The magnetostrictive portion 50 may be exposed on the outside in the radial direction. When the radially outer side of the magnetostrictive portion 50 is exposed, the accommodating portion 33 is constituted by a recessed portion recessed radially inward from the outer peripheral surface of the rotor core 20 . By arranging the magnetostrictive portion 50 within 0% or more and within 10% of the diameter of the rotor core 20 from the outer periphery of the rotor core 20, the magnet 40 can be arranged close to the outer periphery of the rotor core 20, thereby achieving high torque.

According to the above configuration, tensile stress is applied to the magnetostrictive portion 50 due to centrifugal force when the rotor core 20 rotates at high speed, and the relative magnetic permeability in the radial direction is changed, so a device for changing the relative magnetic permeability is separately provided. This eliminates the need for this, contributing to miniaturization and cost reduction. According to the above configuration, by providing the magnetostrictive section 50 to the existing rotor 10, it becomes possible to easily add a variable field function.

According to the above configuration, the relative magnetic permeability in the radial direction can be reduced to 1/10 or less compared to when the magnetostrictive portion 50 is stress-free, and as a result, a variable field width of 30% or more can be obtained. was completed. Furthermore, according to the above configuration, it was possible to apply an average stress of 60 MPa or more to the magnetostrictive portion 50, and a maximum torque of 200 Nm or more was obtained.

Furthermore, in the A20 70kW motor, the magnetic flux starts variable field from 5000 rpm, becomes 70% of the magnetic flux at 12000 rpm, and when the magnetic flux changes to maximize efficiency according to the speed, NEDC (New European The theoretical efficiency in Driving Cycles mode was calculated. The motor having the magnetostrictive section 50 can increase the motor average efficiency by 1.8% and the system efficiency including the gear section and the inverter by 1.5% compared to a motor not having the magnetostrictive section 50. Ta.

[Second embodiment of rotor 10]
A second embodiment of the rotor 10 will be described with reference to FIG. 4.
FIG. 4 is a diagram showing a second embodiment of the rotor of the present invention.
In this figure, the same elements as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

As shown in FIG. 4, the rotor 10 of the second embodiment includes a third magnet hole 34 as the magnet hole 30 and a third magnet 43 as the magnet 40.
When viewed in the axial direction, the third magnet hole 34 has an arc shape that curves and extends in the circumferential direction. The third magnet hole 34 is located inside the housing portion 33 in the radial direction. For example, the magnetic pole center line IL1 passes through the circumferential center of the third magnet hole 34 when viewed in the axial direction. That is, the circumferential position of the circumferential center of the third magnet hole 34 coincides with the circumferential position of the circumferential center of the magnetic pole portion 70, for example. The shape of the third magnet hole 34 when viewed in the axial direction is, for example, a line-symmetrical shape about the magnetic pole center line IL1.

The third magnet hole 34 has a curved portion 34a, one end 34b, and the other end 34c. The curved portion 34a extends in a curved manner in the direction in which the third magnet hole 34 extends when viewed in the axial direction. The curved portion 34a has, for example, an arc shape when viewed in the axial direction. The one end portion 34b is an end portion on one circumferential side (+θ side) of the curved portion 34a. The other end portion 34c is the end portion on the other circumferential side (−θ side) of the curved portion 34a.

The third magnet 43 is housed inside the third magnet hole 34. The third magnet 43 extends along the third magnet hole 34 when viewed in the axial direction. The third magnet 43 extends in a curved manner in the circumferential direction when viewed in the axial direction. The third magnet 43 has an arc shape that curves and extends in the circumferential direction. The circumferential end of the third magnet 43 is located closer to the magnetic pole center line IL1 than the circumferential end of the magnetostrictive portion 50. Therefore, the magnetic flux from the third magnet 43 can be varied outward in the radial direction or in the circumferential direction depending on the relative magnetic permeability of the magnetostrictive portion 50. The shape of the third magnet 43 when viewed in the axial direction is, for example, a shape that is axisymmetric with respect to the magnetic pole center line IL1. When viewed in the axial direction, both ends of the third magnet 43 in the circumferential direction are spaced apart from both ends of the third magnet hole 34 in the circumferential direction.

One end 34b and the other end 34c are arranged adjacent to each other on both sides of the third magnet 43 in the direction in which the third magnet 43 extends when viewed in the axial direction. Here, in this embodiment, the one end portion 34b constitutes a third flux barrier portion 53a. The other end portion 34c constitutes a third flux barrier portion 53b. In other words, the rotor core 20 includes a pair of third

flux barrier parts

53a and 53b that are arranged to sandwich the third magnet 43 in the direction in which the third magnet 43 extends when viewed in the axial direction.

A boundary between the first region 20A and the second region 20B in this embodiment is formed by slits S3 and S4. The slit S3 extends from one end of the third magnet hole 34 in the circumferential direction toward the magnetic pole center line IL1 as it goes radially inward. The slit S4 extends from the other circumferential end of the third magnet hole 34 toward the magnetic pole center line IL1 as it goes radially inward. A third region 20C is provided between the radially inner ends of the slits S3 and S4. The radially outer sides of the slits S3 and S4 are connected to the third magnet hole 34. By connecting the radially outer sides of the slits S3 and S4 to the third magnet hole 34, the first region 20A has a length larger than the circumferential dimension of the third magnet 43 due to centrifugal force when the rotor 10 rotates. Stress can be applied to the magnetostrictive portion 50 by the following steps.

According to the above configuration, it was possible to apply an average stress of 50 MPa or more to the magnetostrictive portion 50, and a maximum torque of 200 Nm or more was obtained.

According to the rotor 10 and rotating electric machine 1 of this embodiment, in addition to obtaining the same functions and effects as those of the first embodiment, the number of magnets is reduced, which contributes to weight reduction and cost reduction.

[Third embodiment of rotor 10]
A third embodiment of the rotor 10 will be described with reference to FIG. 5.
FIG. 5 is a diagram showing a third embodiment of the rotor of the present invention.
In this figure, the same elements as those of the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and the explanation thereof may be omitted or simplified in some cases.

As shown in FIG. 5, the rotor 10 of the third embodiment includes a rotor core 20 and a plurality of magnets 40. The rotor core 20 includes a pair of first magnet holes 31 a and 31 b and a second magnet hole 32 as the plurality of magnet holes 30 . The pair of

first magnet holes

31a and 31b are connected at their radially inner ends. The plurality of magnets 40 include a pair of

first magnets

41a and 41b and a second magnet 45.

The second magnet hole 32 is located radially inside the pair of

first magnet holes

31a and 31b. The end of the second magnet hole 32 on one side in the circumferential direction is located closer to the one side in the circumferential direction than the end of the first magnet hole 31a on the other side in the circumferential direction. The end of the second magnet hole 32 on the other side in the circumferential direction is located on the other side in the circumferential direction than the end of the first magnet hole 31b on the one side in the circumferential direction. That is, both ends of the second magnet hole 32 in the circumferential direction are located further from the magnetic pole center line IL1 than the radially inner sides of the

first magnet holes

31a and 31b.

The pair of

first magnets

41a and 41b are housed inside the pair of

first magnet holes

first magnets

41a and 41b are the same. The lengths of the

first magnets

41a, 41b in the direction orthogonal to the direction in which the pair of

first magnets

41a, 41b extend are the same. The pair of

first magnets

41a and 41b have their respective radially outer ends in contact with the magnetostrictive portion 50.

When viewed in the axial direction, both ends of the first magnet 41a in the stretching direction are arranged apart from both ends of the first magnet hole 31a in the stretching direction. When viewed in the axial direction, an inner end 31d and an outer end 31e are arranged adjacent to each other on both sides of the first magnet 41a in the direction in which the first magnet 41a extends. When viewed in the axial direction, both ends of the first magnet 41b in the extending direction are spaced apart from both ends of the first magnet hole 31b in the extending direction. When viewed in the axial direction, an inner end portion 31d and an outer end portion 31h are arranged adjacent to each other on both sides of the first magnet 41b in the direction in which the first magnet 41b extends. That is, the radially inner ends of the

first magnets

41a, 41b both face the inner end 31d. The inner end portion 31d constitutes a fourth flux barrier portion 54a in the

first magnets

41a, 41b.

The second magnet 45 is housed inside the second magnet hole 32. The second magnet 45 is arranged radially inward from the radially inner end portions of the pair of

first magnets

41a, 41b. The second magnet 45 is located further from the magnetic pole center line IL1 in the circumferential direction than the radially inner end portions of the pair of

first magnets

41a and 41b. The second magnet 45 is arranged at a circumferential position that includes the radially inner ends of the pair of

first magnets

41a and 41b. The second magnet 45 is curved in the circumferential direction when viewed in the axial direction and extends in an arc shape. The radially outer surface of the second magnet 45 faces the fourth flux barrier portion 54a and is exposed. The pair of

first magnets

41a, 41b and second magnet 45 are arranged, for example, along a U shape when viewed in the axial direction.

According to the above configuration, it was possible to apply an average stress of 90 MPa or more to the magnetostrictive portion 50, and a maximum torque of 220 Nm or more was obtained. Further, according to the above configuration, it was possible to obtain a variable field width of 35% or more.

According to the rotor 10 and rotating electric machine 1 of this embodiment, in addition to obtaining the same functions and effects as those of the first embodiment, it is possible to obtain a larger variable field width and maximum torque.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such examples. The various shapes and combinations of the constituent members shown in the above example are merely examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

The rotating electric machine to which the present invention is applied is not limited to a motor, but may be a generator. In this case, the rotating electrical machine may be a three-phase AC generator. The use of the rotating electric machine 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 number of poles and the number of slots of the rotating electric machine are not particularly limited. In a rotating electrical machine, a coil may be wound in any manner. The configurations described above in this specification can be combined as appropriate within a mutually consistent range.

DESCRIPTION OF SYMBOLS 1... Rotating electric machine, 10... Rotor, 20... Rotor core, 20A... First region, 20B... Second region, 30... Magnet hole, 33... Accommodating part, 33a, 33b... Gap, 40... Magnet, 41a, 41b...th 1 magnet, 42, 45...second magnet, 50...magnetostrictive part, 60...stator, 70, 70N, 70S...magnetic pole part, IL1...magnetic pole center line (d axis), S1, S2, S3, S4... slit

Claims

a rotor core provided with 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 parts having magnets arranged in the magnet holes;
a magnetostrictive part that is arranged in the housing part with a gap between the magnetic pole parts and whose relative magnetic permeability changes with elastic deformation;
Equipped with
The magnetostrictive portion is arranged on the d-axis of the magnetic pole portion on the radially outer side of the magnet, and extends in the circumferential direction of the rotor.
The magnetostrictive portion is elastically deformed in the circumferential direction by centrifugal force accompanying rotation of the rotor core.
A rotor according to claim 1.
The magnetic pole portion in the rotor core is
a first region located on the radially outer side;
a second region located on the radially inner side;
Divided into
The first region has a width in the circumferential direction that decreases toward the inside in the radial direction.
The rotor according to claim 1 or 2.
A boundary is formed between the first region and the second region by a slit.
A rotor according to claim 3.
The angle formed by the boundary is larger than the angle occupied by the magnetic pole portion on the rotor core.
A rotor according to claim 4.
The magnet and the magnetostrictive section are arranged line-symmetrically with respect to the d-axis,
A rotor according to any one of claims 1 to 5.
A gap is provided between the inner surface of the magnet hole and the radially inner side surface of the magnet.
A rotor according to any one of claims 1 to 6.
The magnetostrictive portion extends in a curved manner in the circumferential direction.
A rotor according to any one of claims 1 to 7.
The magnetostrictive portion is arranged within 0% or more and 10% of the diameter of the rotor core from the outer periphery of the rotor core.
A rotor according to claim 8.
The plurality of magnets are
a pair of first magnets that are spaced apart 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 to the radially outer side when viewed in the axial direction;
A second magnet disposed at a position in the circumferential direction between the pair of first magnets on the radially outer side of the radially inner end portions of the pair of first magnets, and extending in a direction orthogonal to the radial direction when viewed in the axial direction. magnet and
including,
A rotor according to any one of claims 1 to 9.
The plurality of magnets extend in a curved manner in the circumferential direction.
A rotor according to any one of claims 1 to 9.
The plurality of magnets are
a pair of first magnets that are spaced apart 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 to the radially outer side when viewed in the axial direction;
The magnet is disposed at a circumferential position including the radially inner ends of the pair of first magnets on the radially inner side than the radially inner ends of the pair of first magnets, and is curved in the circumferential direction when viewed in the axial direction. a second magnet extending;
including,
A rotor according to any one of claims 1 to 9.
A rotor according to any one of claims 1 to 12,
a stator facing the rotor;
A rotating electric machine equipped with