JP7797986B2 - Rotor and rotating electric machine - Google Patents

Description

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

For example, in motors used in electric vehicles such as EVs, HEVs, and PHEVs, reducing heat generation is an important issue, as overheating of the motor can lead to reduced performance and reliability. Previously, technologies for reducing heat generation in motors have been investigated.

Motors used in electric vehicles, for example, employ an embedded permanent magnet rotor, in which permanent magnets are embedded. It is known that such motors generate heat due to eddy currents that occur within the permanent magnets while in operation. Patent Document 1 discloses an invention in which the permanent magnets are divided in the direction along the rotor's rotation axis (hereinafter referred to as the axial direction), thereby reducing eddy current loss in the magnets and preventing an increase in magnet temperature that causes demagnetization.

Japanese Patent Application Laid-Open No. 2020-220440

When dividing a permanent magnet in the axial direction, it is possible to arrange the divided magnets at a fixed size so that the temperature of the permanent magnet remains below the desired maximum magnet temperature. Magnets positioned at both axial ends tend to have lower than average magnet temperatures due to their good cooling efficiency, while magnets positioned in the axial center tend to have higher than average magnet temperatures due to their poor cooling efficiency. For this reason, the maximum magnet temperature occurs in the axial center, and the optimal number of divisions is determined for the axial center. However, increasing the number of divisions increases the number of production processes, leading to increased costs.

Furthermore, in rotors made up of multiple magnets, magnets located on the outer diameter side of the rotating shaft are more susceptible to the effects of demagnetizing fields than magnets located on the inner diameter side, which can easily cause demagnetization.

In the past, for example, in configurations where multiple magnets are arranged in the radial direction, no consideration had been given to a structure that could suppress temperature without increasing the number of divisions too much, leaving room for improvement in the structure that suppresses temperature increases in permanent magnets.

The present invention aims to provide a rotating electric machine with an improved structure that suppresses temperature increases in permanent magnets embedded in the rotor.

A rotor according to one aspect of the present invention comprises a shaft extending along a central axis, an iron core to which the shaft is fixed, and magnets that form magnetic poles circumferentially around the iron core, the magnets being arranged in multiple layers at different radial positions around the iron core, the magnets penetrating the iron core in the axial direction and divided into multiple pieces in the axial direction , and the magnets with higher loss density having a greater number of divisions than the magnets with lower loss density .

In the rotor according to one aspect of the present invention, the magnets arranged in the layers with higher loss density among the multiple layers are divided into a greater number of parts than the magnets arranged in the layers with lower loss density among the multiple layers .

A rotor according to one aspect of the present invention comprises a shaft extending along a central axis, an iron core to which the shaft is fixed, and magnets that form magnetic poles circumferentially around the iron core, the magnets being arranged in multiple layers at different radial positions around the iron core, the magnets penetrating the iron core in the axial direction and divided into multiple parts in the axial direction, and the magnets that are more susceptible to demagnetization being divided into more parts than the magnets arranged between the magnets that are more susceptible to demagnetization .

A rotor according to one aspect of the present invention comprises a shaft extending along a central axis, an iron core to which the shaft is fixed, and magnets that form magnetic poles circumferentially around the iron core, the magnets being arranged in multiple layers at different radial positions around the iron core, the magnets penetrating the iron core in the axial direction and divided into multiple pieces in the axial direction, and the magnets having gaps at both ends have a greater number of divisions than the magnets arranged between the magnets having gaps at both ends .

A rotating electric machine according to one aspect of the present invention includes the rotor and a stator disposed radially outside the rotor via an air gap.

One aspect of the present invention provides a rotating electric machine with an improved structure that suppresses temperature increases in permanent magnets embedded in the rotor.

1 is a cross-sectional view of a motor according to a first embodiment of the present invention; FIG. 2 is an enlarged view of a portion of the cross-sectional view shown in FIG. 1 in the motor according to the first embodiment of the present invention. FIG. 3 is a perspective view of the portion shown in FIG. 2 . 2 is a schematic side cross-sectional view showing an example of a division pattern of a permanent magnet 6 according to the first embodiment of the present invention. FIG. FIG. 10 is a schematic cross-sectional side view showing an example of a division pattern of a permanent magnet 6 according to a second embodiment of the present invention. FIG. 10 is a schematic side cross-sectional view showing an example of a division pattern of a permanent magnet 6 according to a third embodiment of the present invention. FIG. 10 is a schematic side cross-sectional view showing an example of a division pattern of a permanent magnet 6 according to a fourth embodiment of the present invention. FIG. 10 is an enlarged view of a part of the cross-sectional view shown in FIG. 1 in a motor according to a fifth embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, to make the description easier to understand, structures and elements other than the main parts of the present invention will be simplified or omitted. In addition, the same elements will be given the same reference numerals in the drawings. Note that the shapes, dimensions, etc. of each element shown in the drawings are shown schematically and do not represent the actual shapes, dimensions, etc.

First Embodiment
FIG. 1 is a cross-sectional view of a motor according to a first embodiment of the present invention. The motor 1 according to the first embodiment is an example of a rotating electric machine. The motor 1 is an inner rotor type motor. FIG. 1 shows a cross-section of the motor 1 in a direction perpendicular to the rotation axis Ax. In FIG. 1, the direction in which the rotation axis Ax of the motor 1 extends is perpendicular to the plane of the page.

Unless otherwise specified, the direction along the extension of the rotation axis Ax, i.e., the direction parallel to the rotation axis Ax, will be referred to simply as the "axial direction." Furthermore, the radial direction centered on the rotation axis Ax will be referred to simply as the "radial direction." Furthermore, the circumferential direction centered on the rotation axis Ax, i.e., around the central axis J, will be referred to simply as the "circumferential direction." In the axial direction, the side indicated by the arrow indicating the axial direction in Figure 3 (described below) will be referred to as the "one axial side," and the opposite side will be referred to as the "other axial side." In the radial direction, the side approaching the rotation axis Ax will be referred to as the "radially inner side," and the side away from the rotation axis Ax will be referred to as the "radially outer side."

The motor 1 has a rotor 2 and a stator 3. The rotor 2 has an iron core 4, a shaft 5, and a permanent magnet 6. The shaft 5 is coaxial with the rotation axis Ax and extends in the axial direction. The rotor 2 is cylindrical and coaxial with the rotation axis Ax. The rotor 2 is an example of an embedded magnet rotor in which the permanent magnet 6 is embedded. The stator 3 is an example of a stator.

The stator 3 is cylindrical and coaxial with the rotation axis Ax. The stator 3 houses the rotor 2 in a space on the radially opposite side. The stator 3 is positioned radially outward from the rotor 2 with a gap between them. On the inner periphery of the stator 3, multiple teeth 3a are arranged at equal intervals around the periphery, each protruding radially inward toward the rotation axis Ax. The spaces between adjacent teeth 3a form slots 3b. The slots 3b house stator coils.

The motor 1 controls the current flowing through the stator coil to sequentially switch the magnetic field of the stator 3, causing the rotor 2 to rotate around the rotation axis Ax due to the attractive or repulsive forces with the magnetic field of the permanent magnet 6 arranged on the rotor 2.

The iron core 4 of the rotor 2 is a cylindrical member formed, for example, by stacking stamped silicon steel plates in the axial direction. An insulating adhesive is interposed between the individual silicon steel plates that make up the iron core 4, so that the individual silicon steel plates are insulated from one another. The iron core 4 is coaxial with the rotation axis Ax. A shaft 5 is fixed to the axial center of the iron core 4 along the rotation axis Ax. The shaft 5 is fixed, for example, by being inserted into the iron core 4. The shaft 5 is rotatably supported by bearings.

The rotor 2 in the first embodiment is an eight-pole rotor, and multiple permanent magnets 6 are arranged in a predetermined array on the iron core 4 of the rotor 2 to form eight main poles equally spaced circumferentially. The permanent magnets 6 are arranged so that adjacent main poles in the rotor 2 along the circumferential direction have opposite polarities.

Figure 2 is an enlarged view of a portion of the cross-sectional view shown in Figure 1. Figure 2 shows one of the eight main poles. The other poles are the same as those in Figure 2, so illustrations and repeated explanations will be omitted. Figure 3 is a perspective view of the portion shown in Figure 2.

In this embodiment, the iron core 4 has through holes 7a, 7b, 7c, and 7d that accommodate the permanent magnets 6. The through holes 7a, 7b, 7c, and 7d pass through the iron core 4 in the axial direction. The through hole 7a accommodates the permanent magnet 6a of the permanent magnets 6. The through hole 7b accommodates the permanent magnet 6b of the permanent magnets 6. The through hole 7c accommodates the permanent magnet 6c of the permanent magnets 6. The through hole 7d accommodates the permanent magnet 6d of the permanent magnets 6.

Through holes 7a, 7b, 7c, and 7d differ in orientation and size, but are similar in shape. Therefore, we will explain the shape of through hole 7a as a representative and omit explanations of through holes 7b, 7c, and 7d.

The through holes 7a are arranged so that the radially outer side is offset counterclockwise by an angle of up to 90 degrees in the circumferential direction from the direction parallel to the radial direction. The cross-sectional shape of the through holes 7a extends in this direction.

Through hole 7b is positioned at a position offset clockwise in the circumferential direction relative to through hole 7a. Through hole 7b is positioned such that the radially outer side is offset clockwise in the circumferential direction by an angle of up to 90 degrees relative to a direction parallel to the radial direction. The cross-sectional shape of through hole 7b extends in this direction.

Through hole 7c is positioned radially outward of through hole 7a. The radially outer side of through hole 7c is positioned in a direction that is offset by an angle of up to 90 degrees counterclockwise in the circumferential direction from a direction parallel to the radial direction. The cross-sectional shape of through hole 7c extends in this direction.

Through hole 7d is positioned radially outward of through hole 7b. Through hole 7d is positioned circumferentially offset clockwise from through hole 7c. Through hole 7d is positioned such that the radially outer side is offset clockwise by an angle of up to 90 degrees from a direction parallel to the radial direction. The cross-sectional shape of through hole 7a extends in this direction.

In this embodiment, permanent magnets 6a and 6b are located at approximately the same radial position and are referred to as the first layer, while permanent magnets 6c and 6d are located at approximately the same radial position and are referred to as the second layer. Permanent magnets 6a and 6a are arranged radially inward of permanent magnets 6c and 6d. As such, in this embodiment, the magnets are arranged in two layers in a two-layer arrangement, but the present invention is not limited to this. A single-layer arrangement in which magnets are arranged in one layer or a multi-layer arrangement in which magnets are arranged in two or more layers is also possible.

The through hole 7a has a central portion 7a1 in which the permanent magnet 6a is embedded. The through hole 7a has an end portion 7a2 radially outward from the central portion 7a1. The through hole 7a has an end portion 7a3 radially inward from the central portion 7a1. The width of the central portion 7a1 in a direction perpendicular to the line connecting the end portions 7a2 and 7a3 is shorter than the widths of the end portions 7a2 and 7a3. The permanent magnet 6a fitted into the central portion 7a1 of the through hole 7a does not reach the end portions 7a2 and 7a3. The end portions 7a2 and 7a3 function as flux barriers.

The axial length of each of the permanent magnets 6a, 6b, 6c, and 6d is approximately equal to the axial length of each of the through holes 7a, 7b, 7c, and 7d. Each of the permanent magnets 6a, 6b, 6c, and 6d passes through the iron core 4 in the axial direction. Regarding permanent magnet 6a as a representative example, both axial ends of the permanent magnet 6a reach both ends of the iron core 4 and are close to the outside of the iron core 4, making heat dissipation easier and preventing the temperature from rising as much as the axial center of the permanent magnet 6a.

Each of the permanent magnets 6a, 6b, 6c, and 6d is divided in the axial direction. Each of the permanent magnets 6a, 6b, 6c, and 6d has a structure in which multiple rectangular parallelepiped magnets are arranged in the axial direction. The shape of each of the permanent magnets 6a, 6b, 6c, and 6d is not limited to a rectangular parallelepiped. In this embodiment, the division pattern of each of the permanent magnets 6a, 6b, 6c, and 6d is a first pattern extending from the axial center to one axial side, and a second pattern extending from the axial center to the other axial side.

Figure 4 is a schematic side cross-sectional view showing an example of the division pattern of the permanent magnet 6 according to the first embodiment of the present invention. In this embodiment, permanent magnets 6a and 6b are examples of inner-circumference magnets, and permanent magnets 6c and 6d are examples of outer-circumference magnets. In Figure 4, permanent magnet 6a is shown as an inner-circumference magnet, and permanent magnet 6c is shown as an outer-circumference magnet. In this embodiment, the first and second patterns have the same magnet division pattern from the axial center toward the axial end, but the present invention is not limited to this, and the first and second patterns may have different division patterns.

In Figure 4, the letters a, b, c, and d in the permanent magnets 6a and 6c indicate the respective divided magnets. Permanent magnet 6a is divided into magnet a, magnet b, magnet c, magnet d, magnet d, magnet c, magnet b, and magnet a, in that order, from one axial end toward the other axial end. Magnets with the same name, such as magnet a at one axial end and magnet a at the other axial end, have the same axial length. The axial length of magnet b is shorter than that of magnet a. The axial length of magnet c is shorter than that of magnet b. The axial length of magnet d is shorter than that of magnet c. In this embodiment, permanent magnet 6c is also divided into magnet a, magnet b, magnet c, magnet d, magnet d, magnet c, magnet b, and magnet a, in that order, from one axial end toward the other axial end. The number of divided magnets shown in Figure 4 is merely an example, and the present invention is not limited thereto.

In this embodiment, the number of magnet divisions decreases from the axial center toward the axial ends. In other words, the permanent magnets 6a and 6c are divided into more fine divisions at the axial center than at the axial ends.

In the example in Figure 4, the division dimensions when the magnet is divided in the axial direction are such that the axial length of the magnet at the axial center is less than the axial length of the magnet at the axial end. A longer axial length of the magnet means fewer divisions in the axial direction.

According to this embodiment, in a configuration in which multiple magnets are arranged radially, the permanent magnets 6a and 6c are divided more finely at the axial center than at the axial ends, thereby suppressing the temperature rise of the permanent magnets embedded in the rotor 2. Furthermore, according to this embodiment, the total number of axial divisions of the magnet can be effectively reduced, thereby reducing manufacturing costs.

In this embodiment, the number of divisions in the axial direction of the magnet is varied depending on the surrounding environment, i.e., ease of heat dissipation. In other words, by reducing the number of divisions in areas where heat dissipation is easy and increasing the number of divisions in areas where heat dissipation is difficult, it is possible to prevent temperature increases while reducing the total number of divisions in the axial direction of the magnet and lower manufacturing costs.

Second Embodiment
5 is a schematic cross-sectional side view showing an example of a division pattern of a permanent magnet 6 according to a second embodiment of the present invention. In the second embodiment, the structures shown in FIGS. 1, 2 and 3 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

In Figure 5, permanent magnet 6a is divided into magnet a, magnet b, magnet c, magnet d, magnet d, magnet d, magnet d, magnet c, magnet b, and magnet a, in that order, from one axial end toward the other axial end. In this embodiment, permanent magnet 6c is also divided into magnet a, magnet b, magnet c, magnet d, magnet d, magnet d, magnet d, magnet c, magnet b, and magnet a, in that order, from one axial end toward the other axial end. The number of magnet divisions shown in Figure 5 is an example, and the present invention is not limited to this. In this embodiment, four magnets d, which have the shortest axial length, are arranged side by side at the axial center, thereby increasing the number of magnet divisions at the axial center. Note that multiple magnets with the same axial length may be arranged adjacent to each other in the axial direction.

In the example of Figure 5, when the magnet is divided in the axial direction, the division dimensions are such that the axial length of the magnet at the axial center is less than or equal to the axial length of the magnet at the axial end. However, if the number of divisions of the outer peripheral magnet and the inner peripheral magnet is the same, it is desirable that the axial length of the axially central magnet be less than the axial length of the axially end magnet.

According to this embodiment, in a configuration in which multiple magnets are arranged radially, the permanent magnets 6a and 6c are divided into smaller pieces at the axial center, thereby suppressing the temperature rise of the permanent magnets embedded in the rotor 2. Furthermore, according to this embodiment, the total number of axial divisions of the magnet can be effectively reduced, thereby reducing manufacturing costs.

Third Embodiment
6 is a schematic side cross-sectional view showing an example of a division pattern of a permanent magnet 6 according to a third embodiment of the present invention. In the third embodiment, the structures shown in FIGS. 1, 2 and 3 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

In Figure 6, permanent magnet 6a is divided into six magnets b, all of which have the same axial length. In this embodiment, permanent magnet 6c is divided into 22 magnets a, all of which have the same axial length. In this embodiment, the axial length of magnet a is shorter than the axial length of magnet b.

In the example of Figure 6, since the loss density of the outer magnet is greater than the loss density of the inner magnet, the number of axial divisions of the outer magnet is greater than the number of axial divisions of the inner magnet. However, depending on the operating range of motor 1, the loss density of the outer magnet may be less than the loss density of the inner magnet, so the number of axial divisions of the outer magnet may be less than the number of axial divisions of the inner magnet.

According to this embodiment, in a configuration in which multiple magnets are arranged radially, the temperature rise of the permanent magnets embedded in the rotor 2 can be suppressed by dividing the outer magnets more finely than the inner magnets. Furthermore, according to this embodiment, the total number of divisions of the magnet in the axial direction can be effectively reduced, thereby reducing manufacturing costs. Furthermore, according to this embodiment, by dividing the magnets into equal axial lengths, manufacturing costs can be reduced.

In this embodiment, the number of divisions in the axial direction of the magnet is varied depending on the surrounding environment, namely loss density. In other words, by increasing the number of divisions for magnets with high loss density and decreasing the number of divisions for magnets with low loss density, it is possible to prevent temperature increases while reducing the total number of divisions in the axial direction of the magnet and lower manufacturing costs.

Fourth Embodiment
7 is a schematic side cross-sectional view showing an example of a division pattern of a permanent magnet 6 according to a fourth embodiment of the present invention. In the fourth embodiment, the structures shown in FIGS. 1, 2 and 3 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

In Figure 7, permanent magnet 6a is divided into magnet a, magnet b, magnet c, magnet d, magnet d, magnet d, magnet d, magnet c, magnet b, and magnet a, in that order, from one axial end toward the other axial end. In this embodiment, permanent magnet 6c is divided into magnet e, magnet f, magnet f, and magnet e, in that order, from one axial end toward the other axial end. The axial length of magnet f is shorter than the axial length of magnet e. The number of divisions of the magnet shown in Figure 7 is one example, and the present invention is not limited to this. In the example of Figure 7, a combination of the division methods shown in Figures 4, 5, and 6 is used.

According to this embodiment, in a configuration in which multiple magnets are arranged radially, the permanent magnets 6a and 6c are divided more finely at the axial center than at the axial ends, thereby suppressing the temperature rise of the permanent magnets embedded in the rotor 2. Also, according to this embodiment, in a configuration in which multiple magnets are arranged radially, the outer peripheral magnets are divided more finely than the inner peripheral magnets, thereby suppressing the temperature rise of the permanent magnets embedded in the rotor 2. Also, according to this embodiment, the total number of axial divisions of the magnet can be effectively reduced, thereby reducing manufacturing costs.

Fifth Embodiment
Fig. 8 is an enlarged view of a portion of the cross-sectional view shown in Fig. 1 in a motor according to a fifth embodiment of the present invention. In this embodiment, the arrangement of magnets in a plane perpendicular to the axial direction is different from that shown in Fig. 2.

In this embodiment, the permanent magnets 6 include permanent magnets 16a, 16b, 16c, 16d, 16e, and 16f. The iron core 4 has through holes that accommodate the permanent magnets 16a, 16b, 16c, 16d, 16e, and 16f.

Permanent magnet 16a is arranged so that its radially outer side is offset counterclockwise by an angle of up to 90 degrees in the circumferential direction from a direction parallel to the radial direction. Permanent magnet 16b is arranged so that its radially outer side is offset clockwise by an angle of up to 90 degrees in the circumferential direction from a direction parallel to the radial direction. Permanent magnet 16c is arranged between permanent magnets 16a and 16b in the circumferential direction, and at the same radially inner position as permanent magnets 16a and 16b in the radial direction.

Permanent magnet 16d is positioned radially outward from permanent magnet 16a. Permanent magnet 16e is positioned radially outward from permanent magnet 16b. Permanent magnet 16f is positioned radially outward from permanent magnet 16c.

Permanent magnet 16d is arranged so that its radially outer side is offset counterclockwise by an angle of up to 90 degrees in the circumferential direction from a direction parallel to the radial direction. Permanent magnet 16e is arranged so that its radially outer side is offset clockwise by an angle of up to 90 degrees in the circumferential direction from a direction parallel to the radial direction. Permanent magnet 16f is arranged between permanent magnets 16d and 16e in the circumferential direction, and in the radial direction at the same position as permanent magnets 16d and 16e radially inside.

Permanent magnets 16a, 16b, 16d, and 16e each have a gap at both ends that functions as a flux barrier. Permanent magnets 16c and 16ef are placed between magnets that have gaps at both ends. Two magnets with gaps at both ends are easily demagnetized. In this embodiment, the number of axial divisions of the two easily demagnetized magnets with gaps at both ends is set to be greater than the number of axial divisions of the magnet placed between the magnets with gaps at both ends. In the example of Figure 8, for example, one permanent magnet 16c is placed between permanent magnets 16a and 16b, but multiple magnets may be placed between permanent magnets 16a and 16b.

According to this embodiment, by dividing permanent magnets 16a and 16b more finely than permanent magnet 16c, it is possible to suppress the temperature rise of the permanent magnets embedded in the iron core 4. Furthermore, according to this embodiment, it is possible to effectively reduce the total number of divisions of the magnet in the axial direction, thereby reducing manufacturing costs.

In this embodiment, the number of divisions in the axial direction of the magnet is varied depending on the surrounding environment, i.e., how easily the magnet is demagnetized. In other words, by increasing the number of divisions for magnets that are easily demagnetized and decreasing the number of divisions for magnets placed between magnets that are easily demagnetized, it is possible to reduce the total number of divisions in the axial direction of the magnet while preventing temperature increases, thereby reducing manufacturing costs.

In this embodiment, permanent magnets 16a, 16b, and 16c may be defined as the first layer, and permanent magnets 16d, 16e, and 16f may be defined as the second layer, and division may be performed using the axial division patterns of the magnets shown in Figures 4 to 7.

According to the present invention as described above, by increasing the number of axial divisions of the magnet in the axial center, where heat dissipation is poor and the magnet temperature is high, and decreasing the number of axial divisions of the magnet at the axial ends, where heat dissipation is good and the magnet temperature is low, it is possible to reduce the average magnet temperature while also reducing the total number of divisions.

Furthermore, according to the present invention, the total number of divisions can be reduced by increasing the number of axial divisions of the outer magnet, which is more susceptible to harmonic currents, and decreasing the number of axial divisions of the inner magnet, which is less susceptible to harmonic currents. Note that, depending on the motor's operating range, the loss density of the outer magnet may be smaller than the loss density of the inner magnet. In this case, the number of axial divisions of the outer magnet may be smaller than the number of axial divisions of the inner magnet. Magnet loss is eddy current loss caused by harmonic currents, and by dividing the magnets and insulating them, eddy currents can be reduced and loss can be reduced. Therefore, by increasing the number of axial divisions of the magnet at the axial center and the number of axial divisions of the outer magnet or inner magnet, whichever has the greater loss density, loss can be reduced and heat generation can be suppressed.

Furthermore, according to the present invention, by increasing the number of divisions of two magnets with gaps at both ends and decreasing the number of divisions of one or more magnets placed between them, it is possible to reduce the total number of divisions while mitigating the effects of demagnetization due to anti-magnetic fields.

In the present invention, the number of divisions of the magnet in the axial direction may be determined based on a combination of the ease of heat dissipation, loss density, and ease of demagnetization in the surrounding environment.

The present invention is not limited to the above-described embodiments, and various improvements and design changes may be made without departing from the spirit of the present invention. The present invention also includes combinations of the various embodiments. Furthermore, the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

1...motor, 2...rotor, 3...stator, 4...iron core, 5...shaft, 6...permanent magnet

Claims (5)

a shaft extending along a central axis;
an iron core to which the shaft is fixed;
a magnet that forms magnetic poles in the circumferential direction of the iron core;
and
the magnets are arranged in a plurality of layers at different radial positions of the iron core,
The magnet is divided into a plurality of pieces in the axial direction by penetrating the iron core in the axial direction ,
The magnet with a high loss density has a larger number of divisions than the magnet with a low loss density.
A rotor characterized by: the magnets arranged in a layer with a higher loss density among the plurality of layers have a larger number of divisions than the magnets arranged in a layer with a lower loss density among the plurality of layers;
2. The rotor according to claim 1 . a shaft extending along a central axis;
an iron core to which the shaft is fixed;
a magnet that forms magnetic poles in the circumferential direction of the iron core;
and
the magnets are arranged in a plurality of layers at different radial positions of the iron core,
The magnet is divided into a plurality of pieces in the axial direction by penetrating the iron core in the axial direction ,
The magnets that are easily demagnetized have a larger number of divisions than the magnets that are arranged between the magnets that are easily demagnetized.
A rotor characterized by: a shaft extending along a central axis;
an iron core to which the shaft is fixed;
a magnet that forms magnetic poles in the circumferential direction of the iron core;
and
the magnets are arranged in a plurality of layers at different radial positions of the iron core,
The magnet is divided into a plurality of pieces in the axial direction by penetrating the iron core in the axial direction ,
The magnet having gaps at both ends has a larger number of divisions than the magnet arranged between the magnets having gaps at both ends.
A rotor characterized by: A rotor according to any one of claims 1 to 4 ;
a stator disposed radially outside the rotor via an air gap;
having
A rotating electric machine characterized by: