JP7517137B2 - Rotor, rotating electric machine, vehicle - Google Patents

Description

The technology disclosed here relates to rotors, rotating electric machines, and vehicles.

Patent document 1 discloses a rotating electric machine having a stator and a rotor. The stator has an armature winding. The rotor has a rotor core, a fixed magnetic force magnet embedded in the rotor core, and variable magnetic force magnets arranged on both sides of the fixed magnetic force magnet. The magnetization state of the variable magnetic force magnet changes with the magnetic field formed by passing current through the armature winding.

JP 2013-51760 A

In the rotating electric machine of Patent Document 1, the magnetization state of the variable magnetic force magnet changes when a magnetic flux in a predetermined direction (e.g., magnetic flux in the same direction as the easy magnetization direction of the variable magnetic force magnet) is applied to the variable magnetic force magnet. However, in the rotating electric machine of Patent Document 1, magnetic flux in an unintended direction (e.g., magnetic flux in the same direction as the difficult magnetization direction of the variable magnetic force magnet) is applied to the variable magnetic force magnet while the rotor is rotating, which may result in an unintended change in the magnetization state of the variable magnetic force magnet.

The technology disclosed here has been developed in light of these issues, and its purpose is to prevent unintended changes in the magnetization state of variable magnets.

The technology disclosed herein relates to a rotor, which includes a rotor core and a plurality of magnetic poles arranged in the circumferential direction on the rotor core, each of which includes a fixed magnet magnetized in the radial direction, a first variable magnet and a second variable magnet arranged at one end and the other end of the fixed magnet in the circumferential direction, respectively, each capable of changing the magnetization state in the circumferential direction by a predetermined magnetic flux, a first anisotropic magnetic member adjacent to the first variable magnet in the circumferential direction, in which the narrow angle between the magnetization easy direction and the magnetization direction of the first variable magnet is smaller than the narrow angle between the magnetization easy direction and a first orthogonal direction perpendicular to the magnetization direction of the first variable magnet, and a second anisotropic magnetic member adjacent to the second variable magnet in the circumferential direction, in which the narrow angle between the magnetization easy direction and the magnetization direction of the second variable magnet is smaller than the narrow angle between the magnetization easy direction and a second orthogonal direction perpendicular to the magnetization direction of the second variable magnet.

In the above configuration, by providing a first anisotropic magnetic member, the direction of the magnetic flux passing through the first variable magnet can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the first variable magnet (unintended direction)" contained in the magnetic flux passing through the first variable magnet can be reduced. This makes it possible to suppress the occurrence of unintended changes in the magnetization state of the first variable magnet.

In addition, in the above configuration, by providing a second anisotropic magnetic member, the direction of the magnetic flux passing through the second variable magnet can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the second variable magnet (unintended direction)" contained in the magnetic flux passing through the second variable magnet can be reduced. This makes it possible to suppress the occurrence of unintended changes in the magnetization state of the second variable magnet.

In addition, in the rotor, the first anisotropic magnetic member may be arranged on the side of the first variable magnet farther from the fixed magnet, and the second anisotropic magnetic member may be arranged on the side of the second variable magnet farther from the fixed magnet.

In the above configuration, the direction of the magnetic flux (e.g., the magnetic flux flowing into the first variable magnet) with respect to the first variable magnet is more likely to change on the side of the first variable magnet farther from the fixed magnet than on the side of the first variable magnet closer to the fixed magnet. Therefore, by providing the first anisotropic magnetic member on the side of the first variable magnet farther from the fixed magnet, it is possible to effectively suppress the occurrence of unintended changes in the magnetization state of the first variable magnet.

In addition, in the above configuration, the direction of the magnetic flux (e.g., the magnetic flux flowing into the second variable magnet) with respect to the second variable magnet is more likely to change on the side of the second variable magnet farther from the fixed magnet than on the side of the second variable magnet closer to the fixed magnet. Therefore, by providing a second anisotropic magnetic member on the side of the second variable magnet farther from the fixed magnet, it is possible to effectively suppress the occurrence of unintended changes in the magnetization state of the second variable magnet.

In addition, in the rotor, each of the multiple magnetic pole portions may have a third anisotropic magnetic member arranged on the side of the first variable magnet closer to the fixed magnet, in which the narrow angle between the magnetization easy direction and the magnetization direction of the first variable magnet is smaller than the narrow angle between the magnetization easy direction and the first orthogonal direction, and a fourth anisotropic magnetic member arranged on the side of the second variable magnet closer to the fixed magnet, in which the narrow angle between the magnetization easy direction and the magnetization direction of the second variable magnet is smaller than the narrow angle between the magnetization easy direction and the second orthogonal direction.

In the above configuration, by providing a third anisotropic magnetic member, the direction of the magnetic flux passing through the first variable magnet can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the first variable magnet (unintended direction)" contained in the magnetic flux passing through the first variable magnet can be further reduced. This makes it possible to further suppress the occurrence of unintended changes in the magnetization state of the first variable magnet.

In addition, in the above configuration, by providing a fourth anisotropic magnetic member, the direction of the magnetic flux passing through the second variable magnet can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the second variable magnet (unintended direction)" contained in the magnetic flux passing through the second variable magnet can be further reduced. This makes it possible to further suppress the occurrence of unintended changes in the magnetization state of the second variable magnet.

Furthermore, in the rotor, a first cutout portion may be provided on the radial outer side of the first variable magnet. A second cutout portion may be provided on the radial outer side of the second variable magnet.

In the above configuration, by providing a first cutout portion on the radial outside of the first variable magnet, the flow of magnetic flux in the circumferential direction on the radial outside of the first variable magnet can be suppressed. This allows the flow of magnetic flux to be concentrated on the first variable magnet. Furthermore, by providing a second cutout portion on the radial outside of the second variable magnet, the flow of magnetic flux in the circumferential direction on the radial outside of the second variable magnet can be suppressed. This allows the flow of magnetic flux to be concentrated on the second variable magnet.

Furthermore, in the rotor, when the narrow angle between the easy magnetization direction of the first anisotropic magnetic member and the magnetization direction of the first variable magnet is _θ11 , the saturation magnetic flux density in the easy magnetization direction of the first anisotropic magnetic member is _B1 , and the saturation magnetic flux density of the rotor core is _B0 , the following formula 1 may be established, and when the narrow angle between the easy magnetization direction of the second anisotropic magnetic member and the magnetization direction of the second variable magnet is _θ21 , the saturation magnetic flux density in the easy magnetization direction of the second anisotropic magnetic member is _B2 , and the saturation magnetic flux density of the rotor core is _B0 , the following formula 2 may be established.

In the above configuration, by setting a narrow angle between the magnetization easy direction of the first anisotropic magnetic member and the magnetization direction of the first variable magnet so that Equation 1 holds, it is possible to increase the "magnetic flux component acting in the magnetization direction (intended direction) of the first variable magnet" contained in the magnetic flux passing through the first variable magnet compared to when the first anisotropic magnetic member is not provided.

In addition, in the above configuration, by setting a narrow angle between the magnetization easy direction of the second anisotropic magnetic member and the magnetization direction of the second variable magnet so that Equation 2 holds, it is possible to increase the "magnetic flux component acting in the magnetization direction (intended direction) of the second variable magnet" contained in the magnetic flux passing through the second variable magnet compared to when the second anisotropic magnetic member is not provided.

The technology disclosed herein also relates to a rotating electric machine, which includes the rotor and a stator that faces the rotor in the radial direction across an air gap.

The technology disclosed herein also relates to a vehicle, the vehicle including the rotating electric machine and drive wheels to which power from the rotating electric machine is transmitted.
A vehicle characterized by:

The technology disclosed herein can effectively suppress the occurrence of unintended changes in the magnetization state of the first variable magnet and the second variable magnet.

1 is a cross-sectional view illustrating a configuration of a rotating electric machine according to an embodiment; 1 is a cross-sectional view illustrating a configuration of a main part of a rotating electric machine according to an embodiment; 4A and 4B are conceptual diagrams illustrating the easy magnetization directions of first and third anisotropic magnetic members. 5A and 5B are conceptual diagrams illustrating the easy magnetization directions of second and fourth anisotropic magnetic members. 10 is a schematic diagram illustrating magnetic flux applied to a first variable magnet in a comparative example of a rotating electric machine. FIG. 4 is a schematic diagram illustrating a magnetic flux applied to a first variable magnet in the rotating electric machine according to the embodiment; FIG. 1 is a schematic diagram illustrating a configuration of a vehicle including a rotating electric machine;

The following describes the embodiments in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals and their description will not be repeated.

(Embodiment)
1 illustrates a configuration of a rotating electric machine 1 according to an embodiment. The rotating electric machine 1 includes a rotor 10, a stator 20, and a shaft 30.

In the following description, the direction of the center of rotation Q of the rotor 10 is referred to as the "axial direction", the direction perpendicular to the axial direction is referred to as the "radial direction", and the direction along the direction of rotation of the rotor 10 is referred to as the "circumferential direction". The side farther from the center of rotation Q is referred to as the "radial outer side", and the side closer to the center of rotation Q is referred to as the "radial inner side". The shape of a cross section perpendicular to the axial direction is referred to as the "cross-sectional shape".

[Stator]
The stator 20 faces the rotor 10 in the radial direction across an air gap. The stator 20 includes a stator core 21 and a plurality of coils 22.

The stator core 21 has a back yoke 21a formed in an annular shape and a number of teeth 21b protruding radially inward from the back yoke 21a. For example, the stator core 21 is a laminated core in which a number of thin sheets of electromagnetic steel are stacked in the axial direction.

The multiple coils 22 are wound around the multiple teeth 21b. When current is applied to the multiple coils 22, magnetic flux is generated in the multiple coils 22. For example, the multiple coils 22 are three-phase coils.

In this example, the magnetic flux generated in the multiple coils 22 includes a rotational magnetic flux, which is a magnetic flux for rotating the rotor 10, and a variable magnetic flux (predetermined magnetic flux), which is a magnetic flux for changing the magnetization state of the first variable magnet 51 and the second variable magnet 52 described below.

For example, by supplying an AC current to the multiple coils 22, a rotating magnetic flux is generated in the multiple coils 22. This rotating magnetic flux rotates the rotor 10. Also, while the rotor 10 is rotating (or stopped), a predetermined current (e.g., a pulse current higher than the AC current that generates the rotating magnetic flux) is supplied to the multiple coils 22 for a predetermined period of time, thereby generating a variable magnetic flux in the multiple coils 22. This variable magnetic flux changes the magnetization state of the first variable magnet 51 and the second variable magnet 52, which will be described later.

[Rotor]
Next, the rotor 10 will be described with reference to Figures 1 and 2. The rotor 10 includes a rotor core 11 and a plurality of magnetic pole portions 12. The straight arrows in the figures illustrate the magnetization directions of the magnets.

[Rotor core]
The rotor core 11 is formed in a cylindrical shape. For example, the rotor core 11 is a laminated core in which a plurality of thin plates made of electromagnetic steel are laminated in the axial direction. A shaft hole S30 is provided in the center of the rotor core 11. A shaft 30 is inserted into and fixed in the shaft hole S30.

[Magnetic pole part]
The multiple magnetic pole portions 12 are provided on the rotor core 11 and are aligned in the circumferential direction. Each of the multiple magnetic pole portions 12 includes a fixed magnet 40, a first variable magnet 51, a second variable magnet 52, a first auxiliary magnet 61, a second auxiliary magnet 62, a first non-magnetic member 71, a second non-magnetic member 72, a first anisotropic magnetic member 81, a second anisotropic magnetic member 82, a third anisotropic magnetic member 83, and a fourth anisotropic magnetic member 84.

<Fixed magnet>
The fixed magnets 40 are embedded in the rotor core 11. In this example, the fixed magnets 40 are housed in fixed magnet holes S40 provided in the rotor core 11. The fixed magnets 40 extend in a direction perpendicular to the radial direction (the tangential direction). Specifically, the fixed magnets 40 have a rectangular cross-sectional shape, and the longitudinal direction faces the tangential direction.

The fixed magnets 40 are magnetized in the radial direction. In this example, multiple fixed magnets 40 are magnetized so that fixed magnets 40 with north poles at their radially outer ends and fixed magnets 40 with south poles at their radially outer ends are arranged alternately in the circumferential direction.

The fixed magnet 40 is a permanent magnet that maintains its magnetization direction. Specifically, the magnetization state of the fixed magnet 40 does not substantially change even when a predetermined magnetic flux (in this example, the variable magnetic flux generated in the coil 22 of the stator 20) is applied. The fixed magnet 40 is a permanent magnet whose magnetization state is less likely to change than the first variable magnet 51 and the second variable magnet 52. For example, the coercive force of the fixed magnet 40 is higher than the coercive force of the first variable magnet 51 and the second variable magnet 52. Examples of the fixed magnet 40 include Nd-Fe-B magnets, Sm-Co magnets, metal magnets (e.g., Fe-Ni magnets), ferrite magnets, etc.

Variable magnet
The first variable magnet 51 included in each of the multiple magnetic pole portions 12 is adjacent to a second variable magnet 52 included in another magnetic pole portion 12 located at one circumferential end side (adjacent in the clockwise direction in the examples of FIGS. 1 and 2 ) of that magnetic pole portion 12, across the q axis. The q axis is an imaginary line that extends radially, passing between two magnetic pole portions 12 adjacent to each other in the circumferential direction.

In addition, in each of the multiple magnetic pole portions 12, the first variable magnet 51 and the second variable magnet 52 are symmetrical with respect to an imaginary line (d-axis) that passes through the center of the fixed magnet 40 in the circumferential direction and extends radially.

First variable magnet
The first variable magnet 51 is disposed on one circumferential end side of the fixed magnet 40. The first variable magnet 51 faces the fixed magnet 40 at a distance in the circumferential direction. The circumferential length between the first variable magnet 51 and the q axis is shorter than the circumferential length between the first variable magnet 51 and the fixed magnet 40.

The first variable magnet 51 is embedded in the rotor core 11. In this example, the first variable magnet 51 is housed in a first variable magnet hole S51 provided in the rotor core 11. The first variable magnet 51 also extends along the q axis (the q axis adjacent in the circumferential direction). Specifically, the first variable magnet 51 has a rectangular cross-sectional shape, and its longitudinal direction is parallel to the q axis.

<Second variable magnet>
The second variable magnet 52 is disposed on the other circumferential end side of the fixed magnet 40. The second variable magnet 52 faces the fixed magnet 40 at a distance in the circumferential direction. The circumferential length between the second variable magnet 52 and the q axis is shorter than the circumferential length between the second variable magnet 52 and the fixed magnet 40.

The second variable magnet 52 is embedded in the rotor core 11. In this example, the second variable magnet 52 is housed in a second variable magnet hole S52 provided in the rotor core 11. The second variable magnet 52 also extends along the q axis (the q axis adjacent in the circumferential direction). Specifically, the second variable magnet 52 has a rectangular cross-sectional shape, and its longitudinal direction is parallel to the q axis.

<Magnetic properties of variable magnets>
Each of the first variable magnet 51 and the second variable magnet 52 is a permanent magnet capable of changing the magnetization state. Specifically, each of the first variable magnet 51 and the second variable magnet 52 is capable of changing the magnetization state in the circumferential direction by a predetermined magnetic flux (in this example, the variable magnetic flux generated in the coil 22 of the stator 20). Each of the first variable magnet 51 and the second variable magnet 52 is a permanent magnet whose magnetization state is easier to change than the fixed magnet 40. For example, the coercive force of the first variable magnet 51 and the second variable magnet 52 is lower than the coercive force of the fixed magnet 40. Examples of the first variable magnet 51 and the second variable magnet 52 include Sm-Co magnets, Nd-Fe-B magnets, metal magnets (e.g., Fe-Ni magnets), ferrite magnets, and Al-Ni-Co magnets.

In this example, the easy magnetization direction of each of the first variable magnet 51 and the second variable magnet 52 is oriented in a direction perpendicular to the radial direction (tangential direction). The hard magnetization direction of the first variable magnet 51 is oriented in a direction perpendicular to the easy magnetization direction of the first variable magnet 51 (radial direction in this example). The hard magnetization direction of the second variable magnet 52 is oriented in a direction perpendicular to the easy magnetization direction of the second variable magnet 52 (radial direction in this example).

In this example, each of the first variable magnet 51 and the second variable magnet 52 can be switched between a first state in which the magnetization direction faces a first direction, a second state in which the magnetization direction faces a second direction, and a zero state in which the magnetic force is substantially zero. The first direction is a direction that increases the magnetic flux (effective magnetic flux) that links with the teeth 21b. The second direction is a direction that decreases the magnetic flux (effective magnetic flux) that links with the teeth 21b. For example, when the magnetization direction of the fixed magnet 40 is a direction toward the radial outward direction, the first direction is a direction from the first variable magnet 51 (or the second variable magnet 52) toward the fixed magnet 40, and the second direction is a direction from the fixed magnet 40 toward the first variable magnet 51 (or the second variable magnet 52).

<Auxiliary magnet>
In each of the multiple magnetic pole portions 12, the first auxiliary magnet 61 and the second auxiliary magnet 62 are symmetrical with respect to an imaginary line (d-axis) that passes through the circumferential center of the fixed magnet 40 and extends radially.

<First auxiliary magnet>
The first auxiliary magnet 61 is disposed between the fixed magnet 40 and the first variable magnet 51. The circumferential length between the first auxiliary magnet 61 and the fixed magnet 40 is shorter than the circumferential length between the first auxiliary magnet 61 and the first variable magnet 51.

The first auxiliary magnet 61 is embedded in the rotor core 11. In this example, the first auxiliary magnet 61 is housed in a first auxiliary magnet hole S61 provided in the rotor core 11. The first auxiliary magnet 61 also extends along one circumferential end of the fixed magnet 40. Specifically, the first auxiliary magnet 61 has a rectangular cross-sectional shape, with its short side facing the longitudinal direction of the fixed magnet 40.

The first auxiliary magnet 61 is magnetized in a direction that obstructs the flow of magnetic flux between the radially outer end of the fixed magnet 40 and the first variable magnet 51. Specifically, when the magnetization direction of the fixed magnet 40 is a direction toward the radially outward direction, the magnetization direction of the first auxiliary magnet 61 is a direction from the first variable magnet 51 toward the fixed magnet 40. When the magnetization direction of the fixed magnet 40 is a direction toward the radially inward direction, the magnetization direction of the first auxiliary magnet 61 is a direction from the fixed magnet 40 toward the first variable magnet 51.

<Second auxiliary magnet>
The second auxiliary magnet 62 is disposed between the fixed magnet 40 and the second variable magnet 52. The circumferential length between the second auxiliary magnet 62 and the fixed magnet 40 is shorter than the circumferential length between the second auxiliary magnet 62 and the second variable magnet 52.

The second auxiliary magnet 62 is embedded in the rotor core 11. In this example, the second auxiliary magnet 62 is housed in a second auxiliary magnet hole S62 provided in the rotor core 11. The second auxiliary magnet 62 also extends along the other circumferential end of the fixed magnet 40. Specifically, the second auxiliary magnet 62 has a rectangular cross-sectional shape, with its short side facing the longitudinal direction of the fixed magnet 40.

The second auxiliary magnet 62 is magnetized in a direction that obstructs the flow of magnetic flux between the radially outer end of the fixed magnet 40 and the second variable magnet 52. Specifically, when the magnetization direction of the fixed magnet 40 is a direction toward the radially outward direction, the magnetization direction of the second auxiliary magnet 62 is a direction from the second variable magnet 52 toward the fixed magnet 40. When the magnetization direction of the fixed magnet 40 is a direction toward the radially inward direction, the magnetization direction of the second auxiliary magnet 62 is a direction from the fixed magnet 40 toward the second variable magnet 52.

<Magnetic properties of auxiliary magnets>
Each of the first auxiliary magnet 61 and the second auxiliary magnet 62 is a permanent magnet that maintains its magnetization direction. Specifically, the magnetization state of each of the first auxiliary magnet 61 and the second auxiliary magnet 62 does not substantially change even when a predetermined magnetic flux (in this example, the variable magnetic flux generated in the coil 22 of the stator 20) is applied. The first auxiliary magnet 61 and the second auxiliary magnet 62 are permanent magnets whose magnetization state is less likely to change than the first variable magnet 51 and the second variable magnet 52. For example, the coercive force of the first auxiliary magnet 61 and the second auxiliary magnet 62 is higher than the coercive force of the first variable magnet 51 and the second variable magnet 52. Examples of the first auxiliary magnet 61 and the second auxiliary magnet 62 include Nd-Fe-B magnets, Sm-Co magnets, metal magnets (e.g., Fe-Ni magnets), ferrite magnets, and the like.

<Details of auxiliary magnet>
In this example, the radially outer ends of the first auxiliary magnet 61 and the second auxiliary magnet 62 are located radially outward from the radially outer end of the fixed magnet 40 .

In this example, the first auxiliary magnet 61 contacts one circumferential end of the fixed magnet 40. Specifically, the first auxiliary magnet hole S61 communicates with the fixed magnet hole S40. The first auxiliary magnet 61 is housed in the first auxiliary magnet hole S61 while in contact with the fixed magnet 40 housed in the fixed magnet hole S40.

In this example, the second auxiliary magnet 62 contacts the other circumferential end of the fixed magnet 40. Specifically, the second auxiliary magnet hole S62 communicates with the fixed magnet hole S40. The second auxiliary magnet 62 is housed in the second auxiliary magnet hole S62 while in contact with the fixed magnet 40 housed in the fixed magnet hole S40.

<Non-magnetic materials>
The first non-magnetic member 71 included in each of the multiple magnetic pole portions 12 is adjacent to a second non-magnetic member 72 included in another magnetic pole portion 12 located on one circumferential end side of the magnetic pole portion 12 (adjacent in the clockwise direction in the examples of Figures 1 and 2).

In each of the multiple magnetic pole portions 12, the first non-magnetic member 71 and the second non-magnetic member 72 are symmetrical about an imaginary line (d-axis) that passes through the center in the circumferential direction of the fixed magnet 40 and extends in the radial direction. For example, the first non-magnetic member 71 and the second non-magnetic member 72 are made of insulating resin.

<First non-magnetic member>
The first non-magnetic member 71 is disposed radially inward of the first auxiliary magnet 61 and the fixed magnet 40. The first non-magnetic member 71 faces the radially inner ends of the first auxiliary magnet 61 and the fixed magnet 40 with a gap therebetween.

The first non-magnetic member 71 is embedded in the rotor core 11. In this example, the first non-magnetic member 71 is accommodated in a first accommodation hole S71 provided in the rotor core 11. The first non-magnetic member 71 also extends along the q axis (the q axis adjacent in the circumferential direction). Specifically, the cross-sectional shape of the first non-magnetic member 71 is formed into a trapezoid. One oblique side of the first non-magnetic member 71 faces in a direction parallel to the q axis, and the other oblique side of the first non-magnetic member 71 faces in a direction parallel to the d axis.

In this example, the first non-magnetic member 71 is a member for holding the first variable magnet 51. Specifically, the first storage hole S71 is connected to the first variable magnet hole S51. The first non-magnetic member 71 has a protruding portion that protrudes toward the first variable magnet 51. The first non-magnetic member 71 is housed in the first storage hole S71 with the protruding portion pressing radially outward against the first variable magnet 51 housed in the first variable magnet hole S51.

In this example, the first non-magnetic member 71 also has a first hollow portion 71a. The first hollow portion 71a penetrates the first non-magnetic member 71 in the axial direction.

<Second non-magnetic member>
The second non-magnetic member 72 is disposed radially inward of the second auxiliary magnet 62 and the fixed magnet 40. The second non-magnetic member 72 faces the radially inner ends of the second auxiliary magnet 62 and the fixed magnet 40 with a gap therebetween.

The second non-magnetic member 72 is embedded in the rotor core 11. In this example, the second non-magnetic member 72 is accommodated in a second accommodation hole S72 provided in the rotor core 11. The second non-magnetic member 72 also extends along the q axis (the q axis adjacent in the circumferential direction). Specifically, the cross-sectional shape of the second non-magnetic member 72 is formed into a trapezoid. One oblique side of the second non-magnetic member 72 faces in a direction parallel to the q axis, and the other oblique side of the second non-magnetic member 72 faces in a direction parallel to the d axis.

In this example, the second non-magnetic member 72 is a member for holding the second variable magnet 52. Specifically, the second housing hole S72 is connected to the second variable magnet hole S52. The second non-magnetic member 72 has a protruding portion that protrudes toward the second variable magnet 52. The second non-magnetic member 72 is housed in the second housing hole S72 with the protruding portion pressing the second variable magnet 52 housed in the second variable magnet hole S52 radially outward.

In this example, the second non-magnetic member 72 also has a second hollow portion 72a. The second hollow portion 72a penetrates the second non-magnetic member 72 in the axial direction.

<Cutout>
A first cutout portion S55 is provided on the radial outer side of the first variable magnet 51. The first cutout portion S55 is provided on the outer circumferential surface of the rotor core 11 and extends in the axial direction. In this example, the first cutout portion S55 communicates with the first variable magnet hole S51.

A second cutout portion S56 is provided on the radially outer side of the second variable magnet 52. The second cutout portion S56 is provided on the outer peripheral surface of the rotor core 11 and extends in the axial direction. In this example, the second cutout portion S56 communicates with the second variable magnet hole S52.

<Vacancy>
A first gap S65 is provided radially outward of the first auxiliary magnet 61. The first gap S65 axially passes through the rotor core 11. In this example, the first gap S65 communicates with the first auxiliary magnet hole S61.

A second gap S66 is provided radially outward of the second auxiliary magnet 62. The second gap S66 penetrates the rotor core 11 in the axial direction. In this example, the second gap S66 communicates with the second auxiliary magnet hole S62.

Anisotropic magnetic components
In each of the multiple magnetic pole parts 12, the first anisotropic magnetic member 81 and the second anisotropic magnetic member 82 are symmetrical with respect to a virtual line (d-axis) that passes through the center in the circumferential direction of the fixed magnet 40 and extends in the radial direction. The third anisotropic magnetic member 83 and the fourth anisotropic magnetic member 84 are symmetrical with respect to the d-axis. Examples of the first to fourth anisotropic magnetic members 81 to 84 include directional electromagnetic steel sheets (also called anisotropic electromagnetic steel sheets) and amorphous magnetic materials that utilize induced magnetic anisotropy. Examples of amorphous magnetic materials that utilize induced magnetic anisotropy include Fe-Co-Si-B and Fe-Co-Si-B-Nb.

In this example, the first anisotropic magnetic member 81 included in each of the multiple magnetic pole parts 12 is adjacent to the second anisotropic magnetic member 82 included in another magnetic pole part 12 located on one circumferential end side of the magnetic pole part 12 (adjacent in the clockwise direction in the examples of Figures 1 and 2).

First anisotropic magnetic member
2 , the first anisotropic magnetic member 81 is adjacent to the first variable magnet 51 in the circumferential direction. In this example, the first anisotropic magnetic member 81 is disposed on the side of the first variable magnet 51 farther from the fixed magnet 40. The first anisotropic magnetic member 81 contacts the first variable magnet 51.

The first anisotropic magnetic member 81 is embedded in the rotor core 11. In this example, the first anisotropic magnetic member 81 is housed in the first variable magnet hole S51 together with the first variable magnet 51 while being in contact with the first variable magnet 51. The first anisotropic magnetic member 81 also extends in the radial direction. Specifically, the first anisotropic magnetic member 81 has a rectangular cross-sectional shape, and its longitudinal direction is parallel to the longitudinal direction of the first variable magnet 51.

As shown in FIG. 3, the narrow angle θ11 between the magnetization easy direction D1 of the first anisotropic magnetic member 81 and the magnetization direction of the first variable magnet 51 is smaller than the narrow angle θ12 between the magnetization easy direction D1 of the first anisotropic magnetic member 81 and a direction perpendicular to the magnetization direction of the first variable magnet 51 (hereinafter referred to as the "first perpendicular direction").

In this example, if the narrow angle θ11 between the magnetization easy direction D1 of the first anisotropic magnetic member 81 and the magnetization direction of the first variable magnet 51 is " _θ11 ", the saturation magnetic flux density of the magnetization easy direction D1 of the first anisotropic magnetic member 81 is " _B1 ", and the saturation magnetic flux density of the rotor core 11 is " _B0 ", the following equation 1 holds.

Second anisotropic magnetic member
2 , the second anisotropic magnetic member 82 is adjacent to the second variable magnet 52 in the circumferential direction. In this example, the second anisotropic magnetic member 82 is disposed on the side of the second variable magnet 52 farther from the fixed magnet 40. The second anisotropic magnetic member 82 contacts the second variable magnet 52.

The second anisotropic magnetic member 82 is embedded in the rotor core 11. In this example, the second anisotropic magnetic member 82 is housed in the second variable magnet hole S52 together with the second variable magnet 52 while being in contact with the second variable magnet 52. The second anisotropic magnetic member 82 also extends in the radial direction. Specifically, the second anisotropic magnetic member 82 has a rectangular cross-sectional shape, and its longitudinal direction is parallel to the longitudinal direction of the second variable magnet 52.

As shown in FIG. 4, the narrow angle θ21 between the magnetization easy direction D2 of the second anisotropic magnetic member 82 and the magnetization direction of the second variable magnet 52 is smaller than the narrow angle θ22 between the magnetization easy direction D2 of the second anisotropic magnetic member 82 and the direction perpendicular to the magnetization direction of the second variable magnet 52 (hereinafter referred to as the "second perpendicular direction").

In this example, if the narrow angle θ21 between the magnetization easy direction D2 of the second anisotropic magnetic member 82 and the magnetization direction of the second variable magnet 52 is " _θ21 ", the saturation magnetic flux density of the magnetization easy direction D2 of the second anisotropic magnetic member 82 is " _B2 ", and the saturation magnetic flux density of the rotor core 11 is " _B0 ", the following equation 2 holds.

<Third anisotropic magnetic member>
2 , the third anisotropic magnetic member 83 is adjacent to the first variable magnet 51 in the circumferential direction. In this example, the third anisotropic magnetic member 83 is disposed on the side of the first variable magnet 51 closer to the fixed magnet 40. The third anisotropic magnetic member 83 contacts the first variable magnet 51.

The third anisotropic magnetic member 83 is embedded in the rotor core 11. In this example, the third anisotropic magnetic member 83 is housed in the first variable magnet hole S51 together with the first variable magnet 51 and the first anisotropic magnetic member 81 while being in contact with the first variable magnet 51. The third anisotropic magnetic member 83 also extends in the radial direction. Specifically, the third anisotropic magnetic member 83 has a rectangular cross-sectional shape, and its longitudinal direction is parallel to the longitudinal direction of the first variable magnet 51.

As shown in FIG. 3, the narrow angle θ31 between the magnetization easy direction D3 of the third anisotropic magnetic member 83 and the magnetization direction of the first variable magnet 51 is smaller than the narrow angle θ32 between the magnetization easy direction D3 of the third anisotropic magnetic member 83 and the first orthogonal direction (the direction orthogonal to the magnetization direction of the first variable magnet 51).

In this example, if the narrow angle θ31 between the magnetization easy direction D3 of the third anisotropic magnetic member 83 and the magnetization direction of the first variable magnet 51 is " _θ31 ", the saturation magnetic flux density of the magnetization easy direction D3 of the third anisotropic magnetic member 83 is " _B3 ", and the saturation magnetic flux density of the rotor core 11 is " _B0 ", the following equation 3 holds.

<Fourth anisotropic magnetic member>
2 , the fourth anisotropic magnetic member 84 is adjacent to the second variable magnet 52 in the circumferential direction. In this example, the fourth anisotropic magnetic member 84 is disposed on the side of the second variable magnet 52 closer to the fixed magnet 40. The fourth anisotropic magnetic member 84 contacts the second variable magnet 52.

The fourth anisotropic magnetic member 84 is embedded in the rotor core 11. In this example, the fourth anisotropic magnetic member 84 is housed in the second variable magnet hole S52 together with the second variable magnet 52 and the second anisotropic magnetic member 82 while in contact with the second variable magnet 52. The fourth anisotropic magnetic member 84 also extends in the radial direction. Specifically, the fourth anisotropic magnetic member 84 has a rectangular cross-sectional shape, and its longitudinal direction is parallel to the longitudinal direction of the second variable magnet 52.

As shown in FIG. 4, the narrow angle θ41 between the magnetization easy direction D4 of the fourth anisotropic magnetic member 84 and the magnetization direction of the second variable magnet 52 is smaller than the narrow angle θ42 between the magnetization easy direction D4 of the fourth anisotropic magnetic member 84 and the second orthogonal direction (the direction orthogonal to the magnetization direction of the second variable magnet 52).

In this example, if the narrow angle θ41 between the magnetization easy direction D4 of the fourth anisotropic magnetic member 84 and the magnetization direction of the second variable magnet 52 is " _θ41 ", the saturation magnetic flux density of the magnetization easy direction D4 of the fourth anisotropic magnetic member 84 is " _B4 ", and the saturation magnetic flux density of the rotor core 11 is " _B0 ", the following equation 4 holds.

[Comparison between the embodiment and the comparative example]
Next, the rotating electric machine 1 of the embodiment and a comparative example of a rotating electric machine will be described with reference to Figures 5 and 6. In the following, for the sake of convenience, the components of the comparative example of the rotating electric machine that are similar to the components of the rotating electric machine 1 of the embodiment are given the same reference numerals as the components of the rotating electric machine 1 of the embodiment. Note that the arrows in the figures illustrate the magnetization direction (direction of easy magnetization) of the first variable magnet 51, and the thin lines in the figures illustrate the flow of magnetic flux.

Figure 5 illustrates the main parts of a comparative example of a rotating electric machine. In this comparative example of a rotating electric machine, instead of the first anisotropic magnetic member 81, a first isotropic magnetic member 91 is arranged on one circumferential end side of the first variable magnet 51. Also, instead of the third anisotropic magnetic member 83, a third isotropic magnetic member 93 is arranged on the other circumferential end side of the first variable magnet 51. Note that the first isotropic magnetic member 91 and the third isotropic magnetic member 93 do not have an easy magnetization direction.

As shown in FIG. 5, the direction of the magnetic flux does not change in the first isotropic magnetic member 91. Furthermore, the direction of the magnetic flux does not change in the third isotropic magnetic member 93.

The first variable magnet 51 is configured so that the magnetization state changes when variable magnetic flux (a predetermined amount of magnetic flux) flows in an intended direction. In this example, when variable magnetic flux flows in the easy magnetization direction of the first variable magnet 51 (the tangential direction in this example), the magnetization state of the first variable magnet 51 changes. However, there is a possibility that the magnetization state of the first variable magnet 51 will change due to magnetic flux flowing in an unintended direction (for example, a difficult magnetization direction perpendicular to the easy magnetization direction of the first variable magnet 51).

Figure 6 illustrates the main parts of the rotating electric machine 1 of the embodiment. In the rotating electric machine 1 of the embodiment, a first anisotropic magnetic member 81 is arranged on one circumferential end side of the first variable magnet 51, and a third anisotropic magnetic member 83 is arranged on the other circumferential end side of the first variable magnet 51. In the example of Figure 6, the magnetization easy direction of each of the first anisotropic magnetic member 81 and the third anisotropic magnetic member 83 is set to be parallel to the magnetization direction (magnetization easy direction) of the first variable magnet 51.

As shown in FIG. 6, the direction of the magnetic flux passing through the first anisotropic magnetic member 81 changes in a direction approaching the easy magnetization direction of the first anisotropic magnetic member 81. As a result, the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the first variable magnet 51" contained in the magnetic flux passing through the first variable magnet 51 is reduced. Similarly, the direction of the magnetic flux passing through the third anisotropic magnetic member 83 changes in a direction approaching the easy magnetization direction of the third anisotropic magnetic member 83. As a result, the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the first variable magnet 51" contained in the magnetic flux passing through the first variable magnet 51 is reduced.

The same can be said about the second variable magnet 52, the second anisotropic magnetic member 82, and the fourth anisotropic magnetic member 84 as about the first variable magnet 51, the first anisotropic magnetic member 81, and the third anisotropic magnetic member 83.

[Effects of the embodiment]
As described above, in the rotor 10 of the embodiment, by providing the first anisotropic magnetic member 81, it is possible to change the direction of the magnetic flux passing through the first variable magnet 51 and reduce "magnetic flux components acting in a direction perpendicular to the magnetization direction of the first variable magnet 51 (unintended direction)" contained in the magnetic flux passing through the first variable magnet 51. This makes it possible to suppress the occurrence of unintended changes in the magnetization state of the first variable magnet 51.

In addition, in the rotor 10 of the embodiment, by providing the second anisotropic magnetic member 82, the direction of the magnetic flux passing through the second variable magnet 52 can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the second variable magnet 52 (unintended direction)" contained in the magnetic flux passing through the second variable magnet 52 can be reduced. This makes it possible to suppress the occurrence of unintended changes in the magnetization state of the second variable magnet 52.

In addition, in the rotor 10 of the embodiment, the first anisotropic magnetic member 81 is provided on the side of the first variable magnet 51 farther from the fixed magnet 40. Note that the direction of the magnetic flux (e.g., the magnetic flux flowing into the first variable magnet 51) with respect to the first variable magnet 51 is more likely to change on the side of the first variable magnet 51 farther from the fixed magnet 40 than on the side of the first variable magnet 51 closer to the fixed magnet 40. Therefore, by providing the first anisotropic magnetic member 81 on the side of the first variable magnet 51 farther from the fixed magnet 40, it is possible to effectively suppress the occurrence of unintended changes in the magnetization state of the first variable magnet 51.

In addition, in the rotor 10 of the embodiment, the second anisotropic magnetic member 82 is provided on the side of the second variable magnet 52 farther from the fixed magnet 40. Note that the direction of the magnetic flux (e.g., the magnetic flux flowing into the second variable magnet 52) for the second variable magnet 52 is more likely to change on the side of the second variable magnet 52 farther from the fixed magnet 40 than on the side of the second variable magnet 52 closer to the fixed magnet 40. Therefore, by providing the second anisotropic magnetic member 82 on the side of the second variable magnet 52 farther from the fixed magnet 40, it is possible to effectively suppress the occurrence of unintended changes in the magnetization state of the second variable magnet 52.

In addition, in the rotor 10 of the embodiment, by providing a third anisotropic magnetic member 83, the direction of the magnetic flux passing through the first variable magnet 51 can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the first variable magnet 51 (unintended direction)" contained in the magnetic flux passing through the first variable magnet 51 can be further reduced. This makes it possible to further suppress the occurrence of unintended changes in the magnetization state of the first variable magnet 51.

In addition, in the rotor 10 of the embodiment, by providing a fourth anisotropic magnetic member 84, the direction of the magnetic flux passing through the second variable magnet 52 can be changed, and the "magnetic flux component acting in a direction perpendicular to the magnetization direction of the second variable magnet 52 (unintended direction)" contained in the magnetic flux passing through the second variable magnet 52 can be further reduced. This makes it possible to further suppress the occurrence of unintended changes in the magnetization state of the second variable magnet 52.

In addition, in the rotor 10 of the embodiment, a first cutout portion S55 is provided on the radial outside of the first variable magnet 51. With this configuration, it is possible to suppress the flow of magnetic flux in the circumferential direction on the radial outside of the first variable magnet 51. This allows the flow of magnetic flux to be concentrated on the first variable magnet 51. In addition, a second cutout portion S56 is provided on the radial outside of the second variable magnet 52. With this configuration, it is possible to suppress the flow of magnetic flux in the circumferential direction on the radial outside of the second variable magnet 52. This allows the flow of magnetic flux to be concentrated on the second variable magnet 52.

In addition, in the rotor 10 of the embodiment, the narrow angle θ11 between the magnetization easy direction D1 of the first anisotropic magnetic member 81 and the magnetization direction of the first variable magnet 51 is set so that Equation 1 holds. With this configuration, it is possible to increase the "magnetic flux component acting in the magnetization direction (intended direction) of the first variable magnet 51" contained in the magnetic flux passing through the first variable magnet 51 compared to the case where the first anisotropic magnetic member 81 is not provided.

In addition, in the rotor 10 of the embodiment, the narrow angle θ21 between the magnetization easy direction D2 of the second anisotropic magnetic member 82 and the magnetization direction of the second variable magnet 52 is set so that Equation 2 is satisfied. With this configuration, it is possible to increase the "magnetic flux component acting in the magnetization direction (intended direction) of the second variable magnet 52" contained in the magnetic flux passing through the second variable magnet 52 compared to the case where the second anisotropic magnetic member 82 is not provided.

In addition, in the rotor 10 of the embodiment, the narrow angle θ31 between the magnetization easy direction D3 of the third anisotropic magnetic member 83 and the magnetization direction of the first variable magnet 51 is set so that Equation 3 is satisfied. With this configuration, it is possible to increase the "magnetic flux component acting in the magnetization direction (intended direction) of the first variable magnet 51" contained in the magnetic flux passing through the first variable magnet 51 compared to the case where the third anisotropic magnetic member 83 is not provided.

In addition, in the rotor 10 of the embodiment, the narrow angle θ41 between the magnetization easy direction D4 of the fourth anisotropic magnetic member 84 and the magnetization direction of the second variable magnet 52 is set so that Equation 4 is satisfied. With this configuration, it is possible to increase the "magnetic flux component acting in the magnetization direction (intended direction) of the second variable magnet 52" contained in the magnetic flux passing through the second variable magnet 52 compared to when the fourth anisotropic magnetic member 84 is not provided.

In addition, in the rotor 10 of the embodiment, by providing the first auxiliary magnet 61 and the second auxiliary magnet 62, it is possible to suppress short-circuiting of the magnetic flux between the radial outer end of the fixed magnet 40 and the first variable magnet 51 and the second variable magnet 52. This allows the magnetic flux of the fixed magnet 40, the first variable magnet 51, and the second variable magnet 52 to be effectively utilized.

(Modification of the embodiment)
In the embodiment, the third anisotropic magnetic member 83 may be omitted. The first anisotropic magnetic member 81 may be disposed on the side of the first variable magnet 51 closer to the fixed magnet 40.

In addition, in the embodiment, the fourth anisotropic magnetic member 84 may be omitted. Furthermore, the second anisotropic magnetic member 82 may be disposed on the side of the second variable magnet 52 closer to the fixed magnet 40.

(vehicle)
7 illustrates an example of the configuration of a vehicle including a rotating electric machine 1. In addition to the rotating electric machine 1, the vehicle includes a control device 2, drive wheels 3, a power transmission mechanism 4, and a battery 5.

The control device 2 controls the rotating electric machine 1. The control device 2 has a drive unit 2a and a control unit 2b. The drive unit 2a drives the rotating electric machine 1 by supplying power to the rotating electric machine 1. The control unit 2b controls the operation of the rotating electric machine 1 by controlling the drive unit 2a.

The power transmission mechanism 4 transmits the power of the rotating electric machine 1 to the drive wheels 3. In this way, the power of the rotating electric machine 1 is transmitted to the drive wheels 3. The battery 5 supplies power to the drive unit 2a and the control unit 2b.

Other Embodiments
In the above description, the rotating electric machine 1 is provided in a vehicle, but the present invention is not limited to this. For example, the rotating electric machine 1 may be provided in a refrigerator, a washing machine, a dryer, or the like.

The above embodiments may be combined as appropriate. The above embodiments are essentially preferred examples and are not intended to limit the scope of the technology disclosed herein, its applications, or its uses.

As explained above, the technology disclosed herein is useful for rotors, rotating electric machines, and vehicles.

Reference Signs List 1 Rotating electric machine 2 Control device 3 Drive wheel 10 Rotor 11 Rotor core 12 Magnetic pole portion 20 Stator 30 Shaft 40 Fixed magnet 51 First variable magnet 52 Second variable magnet 61 First auxiliary magnet 62 Second auxiliary magnet 71 First non-magnetic member 72 Second non-magnetic member 81 First anisotropic magnetic member 82 Second anisotropic magnetic member 83 Third anisotropic magnetic member 84 Fourth anisotropic magnetic member

Claims (7)

A rotor core;
A plurality of magnetic pole portions are provided on the rotor core and arranged in a circumferential direction,
Each of the plurality of magnetic pole portions is
A fixed magnet that is magnetized in the radial direction;
a first variable magnet and a second variable magnet, which are respectively disposed on one end side and the other end side of the fixed magnet in the circumferential direction, and each of which is capable of changing a magnetization state in the circumferential direction by a predetermined magnetic flux;
a first anisotropic magnetic member adjacent to the first variable magnet in the circumferential direction, the narrow angle between the easy magnetization direction and the magnetization direction of the first variable magnet being smaller than the narrow angle between the easy magnetization direction and a first orthogonal direction orthogonal to the magnetization direction of the first variable magnet;
a second anisotropic magnetic member adjacent to the second variable magnet in the circumferential direction, the narrow angle between the easy magnetization direction and the magnetization direction of the second variable magnet being smaller than the narrow angle between the easy magnetization direction and a second orthogonal direction perpendicular to the magnetization direction of the second variable magnet. The rotor of claim 1,
the first anisotropic magnetic member is disposed on a side of the first variable magnet farther from the fixed magnet,
The rotor according to claim 1, wherein the second anisotropic magnetic member is disposed on a side of the second variable magnet farther from the fixed magnet. The rotor of claim 2,
Each of the plurality of magnetic pole portions is
a third anisotropic magnetic member disposed on a side of the first variable magnet closer to the fixed magnet, the narrow angle between the magnetization easy direction and the magnetization direction of the first variable magnet being smaller than the narrow angle between the magnetization easy direction and the first orthogonal direction;
a fourth anisotropic magnetic member arranged on a side of the second variable magnet closer to the fixed magnet, the narrow angle between the easy magnetization direction and the magnetization direction of the second variable magnet being smaller than the narrow angle between the easy magnetization direction and the second orthogonal direction. In any one of claims 1 to 3,
A first cutout portion is provided on a radially outer side of the first variable magnet,
The rotor is characterized in that a second cutout portion is provided on the radially outer side of the second variable magnet. In any one of claims 1 to 4,
If the narrow angle between the magnetization easy direction of the first anisotropic magnetic member and the magnetization direction of the first variable magnet is _θ11 , the saturation magnetic flux density of the magnetization easy direction of the first anisotropic magnetic member is _B1 , and the saturation magnetic flux density of the rotor core is _B0 , the following formula 1 is established:
A rotor characterized in that the following equation 2 is established when the narrow angle between the easy magnetization direction of the second anisotropic magnetic member and the magnetization direction of the second variable magnet is _θ21 , the saturation magnetic flux density of the easy magnetization direction of the second anisotropic magnetic member is _B2 , and the saturation magnetic flux density of the rotor core is _B0 .

A rotor according to any one of claims 1 to 5;
a stator facing the rotor across an air gap in the radial direction. The rotating electric machine according to claim 6 ;
and drive wheels to which the power of the rotating electric machine is transmitted.

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