JP6151050B2 - Rotor and permanent magnet motor - Google Patents

Description

  The present invention relates to a rotor provided with a permanent magnet and a permanent magnet electric motor including a rotor provided with a permanent magnet, and more particularly to a technique for suppressing a short-circuit magnetic flux while suppressing a decrease in strength against centrifugal force.

As a permanent magnet provided in a rotor of a permanent magnet motor, a rare earth magnet such as a neodymium magnet having a high magnetic flux density is used. However, rare earth magnets are expensive. For this reason, the use of a ferrite magnet or the like that is less expensive than a rare earth magnet has been studied.
Here, the ferrite magnet has a lower magnetic flux density than the rare earth magnet. For this reason, when using a ferrite magnet instead of the rare earth magnet, it is necessary to increase the magnet surface area (the magnetic pole surface area of the N pole and the S pole) and increase the amount of magnetic flux generated from the permanent magnet.
As a permanent magnet motor capable of increasing the magnet surface area, a permanent magnet motor disclosed in Patent Document 1 is known. The permanent magnet motor disclosed in Patent Document 1 uses a rotor having a rotor core 1000 shown in FIG. FIG. 16 is a cross-sectional view of the rotor core 1000 viewed from a direction perpendicular to the axial direction. The rotor core 1000 shown in FIG. 16 has a plurality of magnet insertion holes 1011 extending linearly from the rotation center O along the radial direction along the circumferential direction. A permanent magnet 1021 is inserted into the magnet insertion hole 1011. The magnet insertion hole 1011 and the permanent magnet 1021 have a quadrangular cross section.

JP 2010-4722 A

The permanent magnet motor disclosed in Patent Document 1 can increase the amount of magnetic flux generated from a permanent magnet even when a ferrite magnet is used as the permanent magnet.
However, as indicated by broken line arrows in FIG. 16, the magnetic flux is short-circuited through the inner peripheral surface portion of the rotor core. As a method for suppressing the short circuit of the magnetic flux, it is conceivable to reduce the interval W on the inner peripheral surface side of the magnet insertion holes 1011 adjacent in the circumferential direction. On the other hand, when the interval W is reduced, the strength against centrifugal force is reduced. For this reason, there is a limit in reducing the interval W, and the short circuit of the magnetic flux cannot be sufficiently suppressed.
The present invention has been made in view of such a point, and an object of the present invention is to provide a technique capable of suppressing a short circuit of magnetic flux while preventing a decrease in strength against centrifugal force.

The present invention can be configured as follows. In the following, the term “parallel” is used to include “an aspect that is substantially parallel”.
One invention relates to a rotor.
The rotor of the present invention has a rotor core in which a magnet insertion hole into which a permanent magnet is inserted is formed. The rotor core is typically formed by laminating electromagnetic steel sheets. The permanent magnets inserted into the magnet insertion holes and the magnet insertion holes extend along the radial direction when viewed in a cross section perpendicular to the axial direction, and are provided at intervals along the circumferential direction. The main magnetic flux flows by the permanent magnet inserted into the magnet insertion hole, and the d axis (direction of the main magnetic flux) and the q axis (direction perpendicular to the d axis) are defined.
In the present invention, the magnet insertion hole is provided on the inner peripheral side of the first portion (linear insertion portion) extending linearly along the q-axis and on the inner peripheral side from the first portion, and is circular along the circumferential direction. It has the 2nd part (arc-shaped insertion part) extended in the arc shape. The permanent magnet is inserted into the first part of the magnet insertion hole and extends linearly along the q-axis, and the second part of the magnet insertion hole. And a second magnet portion (arc-shaped magnet portion) extending in an arc shape along the circumferential direction. The first magnet portion and the second magnet portion of the permanent magnet are magnetized so that the N-pole main pole and the S-pole main pole are alternately arranged along the circumferential direction. In the present invention, the first magnet portion and the second magnet portion of the permanent magnet are magnetized along the circumferential direction.
A side wall on one side along the circumferential direction of the second portion of the magnet insertion hole is located on one side along the circumferential direction with respect to the permanent magnet inserted into the magnet insertion hole. It is formed in parallel to the d-axis defined by the permanent magnet inserted into the adjacent magnet insertion hole. Further, the side wall on the other direction side in the circumferential direction of the second portion of the magnet insertion hole has a permanent magnet inserted into the magnet insertion hole and the other direction along the circumferential direction with respect to the magnet insertion hole. It is formed in parallel with the d-axis defined by the permanent magnet inserted into the magnet insertion hole adjacent to the side.
And the circumferential direction of the side wall of the one direction side along the circumferential direction of the 2nd part of one magnet insertion hole among the magnet insertion holes adjacent to the circumferential direction, and the 2nd part of the other magnet insertion hole A magnet insertion hole is formed so that a bridge portion having a width and a length capable of suppressing a short circuit of magnetic flux extends along the radial direction between the side wall on the other side along Has been.
In the present invention, the magnet insertion hole is configured by a first portion extending along the radial direction and a second portion provided on the inner peripheral side from the first portion and extending along the circumferential direction. Therefore, the magnet surface area can be increased. Moreover, since the bridge | bridging part which has the width | variety and length which can suppress the short circuit of magnetic flux is formed between the two magnet insertion holes adjacent to the circumferential direction, the short circuit of magnetic flux can be suppressed. In addition, since both side walls of the second portion forming the bridge portion extend in parallel with the d-axis (radial direction), the strength against centrifugal force can be increased. Thereby, even when a ferrite magnet having a magnetic flux density lower than that of the rare earth magnet is used as the permanent magnet, a sufficient amount of magnetic flux can be generated from the permanent magnet. In particular, since the permanent magnet is composed of a first portion extending along the radial direction and a second portion extending along the circumferential direction, the amount of magnetic flux generated from the permanent magnet can be further increased. it can. Moreover, since the 1st magnet part and 2nd magnet part of a permanent magnet are magnetized along the circumferential direction, a 1st magnet part and a 2nd magnet part can be magnetized simultaneously. In particular, magnetization (incorporation magnetization) can be performed in a state where a permanent magnet is incorporated.
In a different form of one invention, the first magnet portion and the second magnet portion of the permanent magnet are formed by separate first and second permanent magnets, respectively.
In this embodiment, since the first magnet portion and the second magnet portion can be formed separately, the permanent magnet can be easily formed.
In another different form of the invention, the first portion of the magnet insertion hole is disposed on one side and the other side along the circumferential direction with respect to the q axis, and extends in parallel to the q axis. It has one side wall and a second side wall. The second portion of the magnet insertion hole has a third side wall and a fourth side wall disposed on one side and the other side along the circumferential direction with respect to the q axis. The third side wall is defined by the permanent magnet inserted into the magnet insertion hole and the permanent magnet inserted into the magnet insertion hole adjacent to the magnet insertion hole on one side along the circumferential direction. Formed parallel to the d-axis. The fourth side wall is defined by a permanent magnet inserted into the magnet insertion hole and a permanent magnet inserted into the magnet insertion hole adjacent to the magnet insertion hole in the other direction along the circumferential direction. Formed parallel to the d-axis. The third and fourth sidewalls act as respective sidewalls along the circumferential direction of the second portion. Preferably, the first portion of the magnet insertion hole has an outer peripheral wall connected to the first side wall and the second side wall. In addition, the second portion of the magnet insertion hole includes a first intermediate wall connected to the first side wall and the third side wall, a second intermediate wall connected to the second side wall and the fourth side wall, It has an inner peripheral wall connected to the third side wall and the fourth side wall.
In this embodiment, the magnet insertion hole can be easily formed.
In another different form of one invention, the outer peripheral surface of the rotor core is a first outer peripheral surface intersecting with the d axis and a second outer peripheral surface intersecting with the q axis when viewed in a cross section perpendicular to the axial direction. Are alternately connected. The first outer peripheral surface is formed in an arc shape having a center of curvature on the d-axis, and the second outer peripheral surface has a center of curvature on the q-axis and is larger than the curvature radius of the first outer peripheral surface. It is formed in the circular arc shape which has. Preferably, the center of curvature of the second outer peripheral surface is set at a position along the q axis in a direction away from the second outer peripheral surface from the rotation center of the rotor core. A portion between the outer peripheral wall of the magnet insertion hole and the outer peripheral surface of the rotor core acts as a bridge portion that suppresses a short circuit of the magnetic flux.
In this embodiment, since the second outer peripheral surface of the rotor core is substantially parallel to the outer peripheral wall of the magnet insertion hole, the distance between the second outer peripheral surface of the rotor core and the outer peripheral wall of the magnet insertion hole is substantially the same. Will be equal. Thereby, the radial width of the bridge portion can be reduced while preventing a decrease in mechanical strength, and a short circuit of magnetic flux can be suppressed.
In another different form of one invention, a ferrite magnet is used as the permanent magnet.
In this embodiment, an inexpensive permanent magnet can be used while ensuring the amount of magnetic flux generated from the magnet.

Another invention relates to a permanent magnet electric motor including a stator and a rotor supported rotatably with respect to the stator. The rotor has a rotor core, a magnet insertion hole formed in the rotor core, and a permanent magnet inserted into the magnet insertion hole. In the present invention, any of the rotors described above is used as the rotor.
The present invention has the effect of each rotor described above.

  By using the rotor and permanent magnet motor of the present invention, it is possible to suppress a short circuit of magnetic flux while suppressing a decrease in strength against centrifugal force.

It is a figure which shows schematic structure of the permanent magnet electric motor of 1st Embodiment. It is sectional drawing of the rotor used with the permanent magnet electric motor of 1st Embodiment. FIG. 3 is a partially enlarged view of FIG. 2. It is sectional drawing of the rotor used with the permanent magnet electric motor of 2nd Embodiment. It is the elements on larger scale of FIG. It is sectional drawing of the rotor used with the permanent magnet electric motor of 3rd Embodiment. It is the elements on larger scale of FIG. It is sectional drawing of the rotor used with the permanent magnet electric motor of 4th Embodiment. It is sectional drawing of the rotor used with the permanent magnet electric motor of 5th Embodiment. FIG. 10 is a partially enlarged view of FIG. 9. It is sectional drawing of the rotor used with the permanent magnet electric motor of 6th Embodiment. It is the elements on larger scale of sectional drawing of the rotor used with the permanent magnet electric motor of 7th Embodiment. It is the elements on larger scale of sectional drawing of the rotor used with the permanent magnet electric motor of 8th Embodiment. It is sectional drawing of the rotor used with the permanent magnet electric motor of 9th Embodiment. It is the elements on larger scale of FIG. It is sectional drawing of the rotor used with the conventional permanent magnet electric motor.

Embodiments of the present invention will be described below with reference to the drawings.
In the present specification, the “axial direction” indicates the direction of the rotation center line passing through the center (rotation center) O of the rotor in a state where the rotor is rotatably supported with respect to the stator. The “circumferential direction” is a circle centered on the rotation center O when viewed in a cross section perpendicular to the axial direction (direction of the rotation center line) in a state where the rotor is rotatably supported with respect to the stator. Indicates the circumferential direction. The “radial direction” indicates a direction passing through the rotation center O when viewed in a cross section perpendicular to the axial direction in a state where the rotor is rotatably supported with respect to the stator.
Further, “d-axis” indicates a direction in which the main magnetic flux of the main magnetic pole (N pole, S pole) formed by the permanent magnet inserted in the magnet insertion hole flows in a cross section perpendicular to the axial direction. The “q-axis” indicates a direction that is electrically perpendicular to the “d-axis”.
Further, the description “parallel” is used to include an aspect of “substantially parallel”.
In the sectional view, “one direction along the circumferential direction” indicates the clockwise direction (clockwise direction), and “the other direction along the circumferential direction” indicates the counterclockwise direction (counterclockwise direction). . Of course, it may be in the opposite direction.

A first embodiment 10 of the permanent magnet motor of the present invention is shown in FIGS. FIG. 1 is a diagram illustrating a schematic configuration of the permanent magnet motor 10 according to the first embodiment. FIG. 2 is a cross-sectional view of the rotor core 100 used in the permanent magnet motor 10 according to the first embodiment when viewed from a direction perpendicular to the axial direction. FIG. 3 is a partially enlarged view of FIG. is there.
The permanent magnet motor 10 according to the first embodiment includes a stator 20 and a rotor 50 that is rotatably supported with respect to the stator 20.
The stator 20 includes a stator core 30 and a stator winding 40. The stator core 30 is formed by stacking electromagnetic steel plates. The stator core 30 includes a yoke extending along the circumferential direction when viewed in a cross section perpendicular to the axial direction, and a plurality of teeth extending from the yoke along the radial direction toward the rotation center of the rotor 50; It has a slot formed by teeth adjacent in the circumferential direction. The stator winding 40 is inserted into the slot.

The rotor 50 includes a rotor core 100 in which a magnet insertion hole into which a permanent magnet is inserted is formed, and a rotating shaft 60.
The rotor core 100 is formed by laminating electromagnetic steel plates. In the present embodiment, the rotor core 100 is formed in a circular shape having a circular outer peripheral surface 101 when viewed in a cross section perpendicular to the axial direction.
The main pole (N pole, S pole) is formed by the permanent magnet inserted into the magnet insertion hole, and the main magnetic flux is generated from the main pole. The “d-axis” is a direction in which the main magnetic flux flows, and the “q-axis” is a direction that is electrically perpendicular to the d-axis (an electrical angle of 90 degrees). (For example, see FIG. 2)

The rotor core 100 is formed with a plurality of magnet insertion holes 111 extending along the radial direction (q-axis) when viewed in a cross section perpendicular to the axial direction.
In the present embodiment, as shown in FIG. 2 and FIG. 3, the magnet insertion hole 111 includes a first portion (linear portion) extending linearly along the radial direction (q-axis). The second portion (arc-shaped portion) is provided on the inner peripheral side (rotation center O side) from the first portion and extends in an arc shape along the circumferential direction.
The first portion (linear portion) of the magnet insertion hole 111 is formed by the outer peripheral wall 111a, the first side wall 111b, and the second side wall 111c. The outer peripheral wall 111a is disposed on the outer peripheral side (the outer peripheral surface 101 side) along the radial direction, and extends linearly. The first side wall 111b and the second side wall 111c are arranged on one side and the other side along the circumferential direction, and extend parallel to the q axis.
The second portion (arc-shaped portion) of the magnet insertion hole 111 is formed by the first intermediate wall 111d, the second intermediate wall 111e, the third side wall 111f, the fourth side wall 111g, and the inner peripheral wall 111h. . The first intermediate wall 111d is connected to the inner peripheral side of the first side wall 111b of the first portion, and extends in an arc shape along the circumferential direction. The second intermediate wall 111e is connected to the inner peripheral side of the second side wall 111c of the first portion, and extends in an arc shape along the circumferential direction. The third side wall 111f is disposed on one side along the circumferential direction, and extends parallel to the d axis on the one side along the circumferential direction from the q axis. The fourth side wall 111g is arranged on the other direction side along the circumferential direction, and extends parallel to the d axis on the other direction side along the circumferential direction from the q axis.

In the present embodiment, the permanent magnet inserted into the magnet insertion hole 111 is inserted into the first portion of the magnet insertion hole 111 and extends linearly along the radial direction (q-axis). Permanent magnet (linear permanent magnet) 121 and a second permanent magnet (arc-shaped permanent magnet) 122 inserted in the second portion of the magnet insertion hole 111 and extending in an arc shape along the circumferential direction. doing. The first permanent magnet 121 corresponds to the “first magnet portion” of the present invention, and the second permanent magnet 122 corresponds to the “second magnet portion” of the present invention.
The first permanent magnet 121 has an outer peripheral surface 121a and an inner peripheral surface 121d that extend linearly along the circumferential direction on both sides along the radial direction when viewed in a cross section perpendicular to the axial direction, along the circumferential direction. On both sides, the first side surface 121b and the second side surface 121c extending linearly in parallel with the q axis are formed in a square shape. The outer peripheral surface 121a, the first side surface 121b, and the second side surface 121c of the first permanent magnet 121 are connected to the outer peripheral wall 111a, the first side wall 111b, and the second side wall 111c of the first portion of the magnet insertion hole 111, respectively. It arrange | positions in the position which opposes.
The second permanent magnet 122 has an outer peripheral surface 122a and an inner peripheral surface 122d that extend in an arc shape along the circumferential direction on both sides along the radial direction when viewed in a cross section perpendicular to the axial direction, along the circumferential direction. The first side surface 122b extending linearly in parallel to the d-axis on one side along the circumferential direction with respect to the q-axis on the one-direction side, and on the q-axis on the other direction side along the circumferential direction On the other hand, it is formed in a circular arc shape by the second side surface 122c extending linearly in parallel with the d-axis on the other direction side along the circumferential direction. The outer peripheral surface 122 a, the first side surface 122 b, the second side surface 121 c and the inner peripheral surface 122 d of the second permanent magnet 122 are the first intermediate wall 111 d and the second intermediate portion of the second part of the magnet insertion hole 111. The wall 111e, the third side wall 111f, the fourth side wall 111g, and the inner peripheral wall 111h are arranged at positions facing each other.

The first permanent magnet 121 and the second permanent magnet 122 inserted into the magnet insertion hole 111 are magnetized (magnetized) so that the adjacent main magnetic poles have different polarities.
In the present embodiment, as shown in FIG. 3, the permanent magnet 121 has a circumferentially facing surface (for example, the first side surface 121 b of one first permanent magnet 121 and the other first magnet 121. The second side surface 121c) of one permanent magnet 121 is magnetized along the circumferential direction so as to have the same pole. That is, the surface on one side along the circumferential direction is one pole (for example, the first side surface 121b is the N pole), and the other side surface is the other pole (for example, the second side surface 121c is the S pole). It is magnetized so that Similarly to the first permanent magnet 121, the second permanent magnet 122 is also a surface facing in the circumferential direction (for example, the first side surface 121 b of one second permanent magnet 121 and the second second magnet 121. Are magnetized along the circumferential direction so that the second side surface 121c) of the permanent magnet 122 has the same pole.
As a method of magnetizing the permanent magnet, a parallel magnetization method of magnetizing in parallel or a radial magnetization method of magnetizing in the radial direction can be used.
In the present embodiment, since the magnetization direction of the first permanent magnet 121 and the magnetization direction of the second permanent magnet 122 are the same, the stator is inserted with the permanent magnets 121 and 122 inserted into the magnet insertion hole 111. A method of magnetizing using a winding or a dedicated winding for magnetization (external magnetization method) can be used.

In the present embodiment, the width that extends along the circumferential direction between the outer peripheral wall 111a of the first portion of the magnet insertion hole 111 and the outer peripheral surface 101 of the rotor core 100 and can suppress a short circuit of the magnetic flux. A bridge portion 105 having a length is formed.
The bridge portion 105 can suppress a short circuit of the magnetic flux through a portion of the rotor core 100 between the magnet insertion hole 111 and the outer peripheral surface 101 of the rotor core 100.
The bridge unit 105 corresponds to the “second bridge unit” of the present invention.
In addition, the first side wall 111f of the second part of one magnet insertion hole 111 and the second side wall of the second part of the other magnet insertion hole 111 among the two magnet insertion holes 111 adjacent in the circumferential direction. 111 g forms a bridge portion 106 that extends along the d-axis and has a width (length along the circumferential direction) and a length (length along the d-axis) that can suppress a short circuit of magnetic flux. ing.
By this bridge portion 106, it is possible to prevent the magnetic flux from being short-circuited through a portion of the rotor core 100 between the magnet insertion holes 111 adjacent in the circumferential direction.
The bridge unit 106 corresponds to the “first bridge unit” of the present invention.
Preferably, the bridge portion 106 has an interval (width) along the circumferential direction set within a range of 0.35 mm to 0.5 mm, and a length (length) along the radial direction of 1.5 mm. Set as above.

In the present embodiment, since the permanent magnet is arranged so as to extend along the radial direction, the magnet surface area of the permanent magnet can be increased, and the amount of magnetic flux generated from the permanent magnet can be increased.
In particular, as a permanent magnet, a first permanent magnet (first magnet portion) (121) extending linearly along the radial direction (q-axis), and an inner peripheral side from the first permanent magnet (121) In the case where only the first permanent magnet (121) is used because the second permanent magnet (second magnet portion) (122) is arranged in a circular arc shape along the circumferential direction. The amount of magnetic flux can be increased compared to
In addition, among the magnet insertion holes (111) adjacent in the circumferential direction, the third side wall (111f) of the second portion of one of the magnet insertion holes (111) into which the second permanent magnet (122) is inserted. Between the other magnet insertion hole (111) and the fourth side wall (111g) of the second portion into which the second permanent magnet (122) is inserted (the bridge portion extending along the d-axis ( 106) is formed. Thereby, it can suppress that a magnetic flux short-circuits via the part between the magnet insertion holes (111) adjacent to the circumferential direction of a rotor core (100). Furthermore, the third side wall (111f) and the fourth side wall (111g) forming the bridge portion (106) extend in parallel to the d-axis (radial direction). Thereby, the intensity | strength with respect to the centrifugal force which acts on the rotor core (100) during rotation can be made high.
Therefore, as a permanent magnet provided on the rotor, even when a ferrite magnet with a low magnetic flux density but a low magnetic flux density is used instead of a rare earth magnet with a high magnetic flux density, the strength against centrifugal force is reduced and the magnetic flux is short-circuited. It is possible to secure a sufficient amount of magnetic flux while suppressing.

  Next, another embodiment of the present invention will be described below. In the following embodiment, since the configuration of the stator is the same as that of the first embodiment, only the configuration of the rotor will be described. In addition, among the reference numerals attached to the constituent elements of the following embodiment and the reference numerals attached to the constituent elements of the first embodiment, reference numerals in which the numerals other than the third digit are the same. Constituent elements marked with are the same.

A rotor core 200 of a rotor according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a cross-sectional view of the rotor core 200 of the rotor according to the second embodiment viewed from a direction perpendicular to the axial direction, and FIG. 5 is a partially enlarged view of FIG.
The rotor core 200 according to the present embodiment includes a first portion (linear portion) extending linearly along the q axis, and the first portion, similarly to the rotor core 100 according to the first embodiment. A magnet insertion hole 211 having a second portion (arc-shaped portion) that is disposed on the inner peripheral side from the portion and extends in an arc shape along the circumferential direction is formed.
In addition, the permanent magnet inserted into the magnet insertion hole 211 is inserted into the first part of the magnet insertion hole 211 and linearly along the q axis, as in the rotor core 100 of the first embodiment. A first permanent magnet (first magnet portion) 221 that extends and a second permanent magnet (second magnet) that is inserted into the second portion of the magnet insertion hole 211 and extends in an arc shape along the circumferential direction. Magnet portion) 222.

Then, the first permanent magnet 221 and the second permanent magnet 222 inserted into the magnet insertion hole 211 are magnetized (magnetized) so that the adjacent main magnetic poles have different polarities.
In the present embodiment, the magnetization direction of the permanent magnet is different from that of the first embodiment.
That is, as shown in FIG. 5, the permanent magnet 221 is similar to the first permanent magnet 121 of the first embodiment so that the surfaces facing each other along the circumferential direction have the same poles. Magnetized along the circumferential direction.
On the other hand, the second permanent magnet 222 is magnetized in the radial direction. For example, the second permanent magnet 222 is magnetized so that the outer peripheral surface 222a is an N pole and the inner peripheral surface 222d is an S pole. At this time, a portion of the outer peripheral surface 222a of the second permanent magnet 222 that faces the first side surface 221b of the first permanent magnet 221 has the same polarity as the first side surface 221b and faces the second side surface 221c. The portion to be magnetized is the same polarity as the second side surface 221c. That is, in the second permanent magnet 222, a portion on one side along the circumferential direction and a portion on the other side are magnetized so as to have different polarities along the radial direction. In the present embodiment, the outer peripheral surface 222a is an N pole, and the inner peripheral surface 222d is an S pole, with the second permanent magnet at a center line along the circumferential direction as a boundary, The other side of the circumferential direction is magnetized so that the outer peripheral surface 222a is an S pole and the inner peripheral surface 222d is an N pole.
In the present embodiment, since the second permanent magnet 222 extending in an arc shape along the circumferential direction is magnetized in the radial direction, the portion between the magnet insertion holes 221 adjacent in the circumferential direction is interposed. Magnetic flux is difficult to short circuit. In addition, the amount of magnetic flux can be increased more than in the first embodiment.

A rotor core 300 of a rotor according to a third embodiment of the present invention will be described with reference to FIGS. 6 is a cross-sectional view of the rotor core 300 of the rotor according to the third embodiment as viewed from a direction perpendicular to the axial direction, and FIG. 7 is a partially enlarged view of FIG.
The magnet insertion hole 311 formed in the rotor core 300 of the present embodiment, the first permanent magnet 321 and the second permanent magnet 322 inserted into the magnet insertion hole 311 are the rotations of the first embodiment. The configuration is the same as the magnet insertion hole 111, the first permanent magnet 121, and the second permanent magnet 122 formed in the child core 100.

In the rotor core 300 of the present embodiment, the shape of the outer peripheral surface 311 of the rotor core 300 is different from the shape of the outer peripheral surface 101 of the rotor core 100 of the first embodiment.
The outer peripheral surface 301 of the rotor core 300 is configured by alternately arranging the first curved portion 301A and the second curved portion 301B when viewed in a cross section perpendicular to the axial direction.
The first curved portion 301 </ b> A is formed in a first curved shape that intersects the d-axis and protrudes in the outer circumferential direction of the rotor core 300. The second curved portion 301B is formed in a second curved shape that intersects the q axis and protrudes in the outer circumferential direction of the rotor core 300. The first curved shape is an arc shape having a radius R1 with the center of curvature at the rotation center O on the d-axis. The second curved line shape is an arc shape having a radius R2 (> R1) having a center of curvature at a point P on the q axis that is away from the rotation center O in the direction opposite to the second curved line portion 301B.
The first curved portion 301A corresponds to the “first outer peripheral surface” of the present invention, and the second curved portion 301B corresponds to the “second outer peripheral surface” of the present invention.
In the present embodiment, when the switching portion 301a between the first curved portion (301A) and the second curved portion (301B) passes through a location facing the teeth, a rapid change in the amount of magnetic flux flowing through the teeth is suppressed. can do. Thereby, it is possible to prevent an increase in the harmonic component included in the waveform of the induced voltage induced in the stator winding due to a sudden change in the amount of magnetic flux flowing through the teeth. Therefore, the inverter can be accurately controlled based on the induced voltage of the stator winding.
Further, since the distance between the outer peripheral wall 311a of the first portion of the magnet insertion hole 311 and the second curved portion 301B of the outer peripheral surface 301 of the rotor core 300 is substantially equal, the outer peripheral wall 311a and the second curved line An interval between the portion 301B can be reduced, and a short circuit of magnetic flux can be suppressed. When the outer peripheral surface 301 of the rotor core has a circular shape, the distance between both end portions along the circumferential direction of the outer peripheral wall 311a and the outer peripheral surface 301 is the central portion and the outer peripheral surface along the circumferential direction. It is smaller than the distance between 301. For this reason, it is necessary to design that the part between the both ends of the outer peripheral wall 311a and the outer peripheral surface 301 has the intensity | strength with respect to a centrifugal force, and there exists a limit in suppressing the short circuit of magnetic flux.

A rotor core 400 of a rotor according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of the rotor core 400 of the rotor according to the fourth embodiment as viewed from a direction perpendicular to the axial direction.
The magnet insertion hole 411 formed in the rotor core 400 of the present embodiment, the first permanent magnet 421 and the second permanent magnet 422 inserted into the magnet insertion hole 411 are the rotations of the second embodiment. The configuration is the same as the magnet insertion hole 211, the first permanent magnet 221, and the second permanent magnet 222 formed in the child core 200.
Further, the outer peripheral surface 401 of the rotor core 400 is formed by alternately arranging the first curved portion 401A and the second curved portion 401B in the same manner as the outer peripheral surface 301 of the rotor core 300 of the third embodiment. It is configured. The first curve shape is an arc shape having a radius R1 that intersects the d-axis and has a center of curvature at the center of rotation O on the d-axis. The second curved line shape is an arc shape having a radius R2 (> R1) that intersects the q-axis and has a curvature center at a point P on the q-axis that is away from the second curved line portion 401B from the rotation center O.

A rotor core 500 of a rotor according to a fifth embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a cross-sectional view of a rotor core 500 of a rotor according to a fifth embodiment viewed from a direction perpendicular to the axial direction, and FIG. 10 is a partially enlarged view of FIG.
In the rotor core 500 of the present embodiment, a first portion (straight portion) extending linearly along the q axis, and the first portion, like the rotor core 100 of the first embodiment, A magnet insertion hole 511 is formed having a second portion (arc-shaped portion) that is arranged on the inner peripheral side from the portion and extends in an arc shape along the circumferential direction.

In the rotor core 100 of the first embodiment, the two permanent magnets 121 and 122 are inserted into the magnet insertion hole 111, but in the rotor core 500 of the present embodiment, one permanent magnet 521 is inserted. doing.
As shown in FIG. 10, the permanent magnet 521 is inserted into the first portion of the magnet insertion hole 511 when viewed in a cross section perpendicular to the axial direction, and linearly extends along the radial direction (q axis). A first magnet portion (linear magnet portion) that extends and a second magnet portion (arc-shaped magnet portion) that is inserted into the second portion of the magnet insertion hole 511 and extends in an arc shape along the circumferential direction. )have.
The first magnet portion (linear magnet portion) of the permanent magnet 521 is formed by the outer peripheral surface 521a, the first side surface 521b, and the second side surface 521c. The outer peripheral surface 521a is disposed on the outer peripheral side (the outer peripheral surface 501 side) along the radial direction, and extends linearly. The first side surface 521b and the second side surface 521c are arranged on one side and the other side along the circumferential direction, and extend parallel to the q axis.
The second magnet portion (arc-shaped magnet portion) of the permanent magnet 521 is formed by the first intermediate surface 521d, the second intermediate surface 521e, the third side surface 521f, the fourth side surface 521g, and the inner peripheral surface 521h. ing. The first intermediate surface 521d is connected to the inner peripheral side of the first side surface 521b of the first magnet portion, and extends in an arc shape along the circumferential direction. The second intermediate surface 521e is connected to the inner peripheral side of the second side surface 521c of the first magnet portion, and extends in an arc shape along the circumferential direction. The third side surface 521f is disposed on one side along the circumferential direction, and extends in parallel to the d axis on the one direction side along the circumferential direction from the q axis. The fourth side surface 521g is arranged on the other direction side along the circumferential direction, and extends in parallel to the d axis on the other direction side along the circumferential direction from the q axis.
The outer peripheral surface 521a, the first side surface 521b, the second side surface 521c, the first intermediate surface 521d, the second intermediate surface 521e, the third side surface 521f, the fourth side surface 521g and the inner peripheral surface 521h of the permanent magnet 521. Are the outer peripheral wall 511a, the first side wall 511b, the second side wall 511c, the first intermediate wall 511d, the second intermediate wall 511e, the third side wall 511f, the fourth side wall 521g and the inner wall of the magnet insertion hole 511. It arrange | positions in the position facing the surrounding wall 511h.
Further, in the present embodiment, the permanent magnet 521 is a surface facing along the circumferential direction (for example, the first side surface 521b and the third side surface 521f of one permanent magnet 521, and the first surface of the other permanent magnet 521). The second side surface 521c and the fourth side surface 521g) are magnetized along the circumferential direction so as to have the same pole.

A rotor core 600 of a rotor according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view of the rotor core 600 of the rotor according to the sixth embodiment when viewed from a direction perpendicular to the axial direction.
The magnet insertion hole 611 formed in the rotor core 600 of the present embodiment and the permanent magnet 621 inserted in the magnet insertion hole 611 are magnets formed in the rotor core 500 of the fifth embodiment. The configuration is the same as that of the permanent magnet 521 inserted into the insertion hole 511 and the magnet insertion hole 511.
In addition, the outer peripheral surface 601 of the rotor core 600 is formed by alternately arranging the first curved portions 601A and the second curved portions 601B in the same manner as the outer peripheral surface 301 of the rotor core 300 of the third embodiment. It is configured.

A rotor core 700 of a rotor according to a seventh embodiment of the present invention will be described with reference to FIG. FIG. 12 is a partially enlarged view of a sectional view of the rotor core 700 of the rotor according to the seventh embodiment viewed from a direction perpendicular to the axial direction.
In rotor core 700 of the present embodiment, the corners of the permanent magnet are formed in an R shape (arc shape) when viewed in a cross section perpendicular to the axial direction. That is, an R surface (arc-shaped surface) 721 e is formed at the corner of the first permanent magnet 721, and an R surface 722 e is formed at the corner of the second permanent magnet 722. The corners forming the R plane can be selected as appropriate.

A rotor core 800 of a rotor according to an eighth embodiment of the present invention will be described with reference to FIG. FIG. 13 is a partial enlarged view of a cross-sectional view of a rotor core 800 of a rotor according to an eighth embodiment as viewed from a direction perpendicular to the axial direction.
In the rotor core 800 of the present embodiment, the corners of the permanent magnet are formed in a tapered shape (straight shape) when viewed in a cross section perpendicular to the axial direction. That is, a tapered surface (linear surface) 821 f is formed at the corner of the first permanent magnet 821, and a tapered surface 822 f is formed at the corner of the second permanent magnet 822. The corners forming the tapered surface can be selected as appropriate.

A rotor core 900 of a rotor according to a ninth embodiment of the present invention will be described with reference to FIGS. 14 and 15. FIG. 14 is a cross-sectional view of a rotor core 900 of a rotor according to the ninth embodiment as viewed from a direction perpendicular to the axial direction, and FIG. 15 is a partially enlarged view of FIG.
In the rotor cores 100 to 800 of the first to eighth embodiments, a magnet insertion hole having a linear portion and an arc-shaped portion and a permanent magnet having a linear magnet portion and an arc-shaped magnet portion are used. In the rotor core 900 of the present embodiment, a magnet insertion hole 911 having a linear portion and a permanent magnet having a linear magnet portion are used.

As shown in FIG. 15, the magnet insertion hole 911 has an outer peripheral wall 911a, a first side wall 911b, a second side wall 911c, a first inclined wall 911i, The two inclined walls 911j and the inner peripheral wall 911h are formed.
The outer peripheral wall 911a is arranged on the outer peripheral side along the radial direction and extends linearly. The first side wall 911b and the second side wall 911c are disposed on the inner peripheral side of the outer peripheral wall 911a on one side and the other side along the circumferential direction, and extend in parallel to the q axis. The inner peripheral wall 911h is disposed on the inner peripheral side along the radial direction and extends linearly. The first inclined wall 911i is connected to the first side wall 911b and the inner peripheral wall 911h (arranged on one side along the circumferential direction), and is parallel to the d axis on the one side along the circumferential direction from the q axis. It extends in a straight line. The second side wall 911j is connected to the second side wall 911c and the inner peripheral wall 911h (arranged on the other direction side along the circumferential direction) and parallel to the d axis on the other direction side along the circumferential direction from the q axis. It extends in a straight line.

The permanent magnet 921 extends linearly in parallel to the q axis on both sides along the circumferential direction, the outer circumferential surface 921a and the inner circumferential surface 921h extending linearly on both sides along the radial direction. The first side surface 921b and the second side surface 921c are connected to the first side surface 921b and the inner peripheral surface 921h, and extend in a straight line parallel to the d-axis, and the second side surface 921c. The second inclined surface 921j is connected to the inner peripheral surface 921h and extends linearly in parallel with the d-axis. The outer peripheral surface 921a, the first side surface 921b, the second side surface 921c, the first inclined surface 921i, the second inclined surface 921j, and the inner peripheral surface 921h of the permanent magnet 921 are the outer peripheral wall 911a of the magnet insertion hole 911, the first The side wall 911b, the second side wall 911c, the first inclined wall 911i, the second inclined wall 911j, and the inner peripheral wall 911h are arranged at positions facing each other.
Further, the permanent magnet 921 is configured so that the surfaces facing in the circumferential direction (for example, the first side surface 921b of one permanent magnet 921 and the second side surface 921c of the other permanent magnet 921) have the same pole. Magnetized along the circumferential direction. That is, one surface along the circumferential direction is one pole (for example, the first side surface 921b is the N pole), and the other surface is the other pole (for example, the second side surface 921c is the S pole). It is magnetized to become.

Further, in the present embodiment, the width and length that extend along the circumferential direction between the outer peripheral wall 911a of the magnet insertion hole 911 and the outer peripheral surface 901 of the rotor core 900 and can suppress a short circuit of magnetic flux. A bridge portion 905 having the shape is formed.
The bridge portion 905 can suppress a short circuit of the magnetic flux through a portion of the rotor core 900 between the magnet insertion hole 911 and the outer peripheral surface 901 of the rotor core 900.
The bridge unit 905 corresponds to a “second bridge unit” of the present invention.
Further, along the d-axis, the first inclined wall 911i of one magnet insertion hole 911 and the second inclined wall 911j of the other magnet insertion hole 911 out of two magnet insertion holes 911 adjacent in the circumferential direction. Thus, a bridge portion 906 having a width (length along the circumferential direction) and a length (length along the d-axis) that can suppress a short circuit of the magnetic flux is formed.
The bridge portion 906 can prevent the magnetic flux from being short-circuited through the portion of the rotor core 900 between the magnet insertion holes 911 adjacent in the circumferential direction.
The bridge unit 906 corresponds to the “first bridge unit” of the present invention.
Preferably, the width of the bridge portion 906 is set to 0.35 mm to 0.5 mm, and the length of the bridge 906 is set to 1.5 mm or more.

In the present embodiment, since the permanent magnet is arranged so as to extend along the radial direction, the magnet surface area of the permanent magnet can be increased, and the amount of magnetic flux generated from the permanent magnet can be increased.
Of the magnet insertion holes (911) adjacent in the circumferential direction, the first slant wall (911i) of one magnet insertion hole (911) and the second slant wall (911) of the other magnet insertion hole (911) ( 911j), a bridge portion (906) extending along the d-axis is formed. Thereby, it can suppress that a magnetic flux short-circuits via the part between the magnet insertion holes (911) adjacent to the circumferential direction of a rotor core (900). Furthermore, the first slant wall (911i) and the second slant wall (911j) forming the bridge portion (906) extend in parallel to the d-axis (radial direction). Thereby, the intensity | strength with respect to the centrifugal force which acts on the rotor core (900) during rotation can be made high.
Therefore, as a permanent magnet provided on the rotor, even when a ferrite magnet with a low magnetic flux density but a low magnetic flux density is used instead of a rare earth magnet with a high magnetic flux density, the strength against centrifugal force is reduced and the magnetic flux is short-circuited. It is possible to secure a sufficient amount of magnetic flux while suppressing.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions are possible.
Each structure described in the embodiment can be used alone, or can be appropriately selected and used in combination.
The permanent magnet is not limited to a ferrite magnet, and various permanent magnets including rare earth magnets can be used.
The shape of the magnet insertion hole and the permanent magnet is not limited to the shape described in the embodiment, and can be set to various shapes.

The present invention includes a “rotor core, a magnet insertion hole formed in the rotor core, and a permanent magnet inserted into the magnet insertion hole. The rotor and the permanent magnet extend along the radial direction, and a plurality of the permanent magnets are provided along the circumferential direction, and the d-axis and the q-axis are defined by the permanent magnet. The hole has a first portion that extends linearly along the q-axis, and a second portion that is provided on the inner peripheral side of the first portion and extends in an arc shape along the circumferential direction. The permanent magnet has a first magnet part inserted into the first part of the magnet insertion hole and a second magnet part inserted into the second part of the magnet insertion hole, and the magnet A side wall on one side along the circumferential direction of the second portion of the insertion hole is a permanent magnet inserted into the magnet insertion hole. And a permanent magnet inserted into a magnet insertion hole adjacent to the magnet insertion hole on one side along the circumferential direction with respect to the magnet insertion hole. The side wall in the other direction along the circumferential direction of the portion 2 is a permanent magnet inserted into the magnet insertion hole and a magnet insertion hole adjacent to the magnet insertion hole in the other direction along the circumferential direction. Formed in parallel to the d-axis defined by the permanent magnet inserted into the
  A bridge portion is formed by the side wall on the one-direction side of the second portion of one magnet insertion hole and the side wall on the other-direction side of the second portion of the other magnet insertion hole among the magnet insertion holes adjacent in the circumferential direction. Rotor characterized by being made. (Aspect 1).
Also, “in the rotor of aspect 1, the first magnet portion and the second magnet portion of the permanent magnet are respectively formed by separate first and second permanent magnets. (Aspect 2) ”.
Further, “the rotor according to aspect 1 or 2, wherein the first portion of the magnet insertion hole is disposed on one side and the other side along the circumferential direction with respect to the q axis, and is parallel to the q axis. And the second portion of the magnet insertion hole is disposed on one direction side and the other direction side along the circumferential direction with respect to the q axis. 3 side walls and a fourth side wall, and the third side wall is a permanent magnet inserted into the magnet insertion hole and a magnet adjacent to the magnet insertion hole on one side along the circumferential direction. The fourth side wall extends in parallel with the permanent magnet inserted into the magnet insertion hole, and extends in parallel with the d-axis defined by the permanent magnet inserted into the insertion hole. Parallel to the d axis defined by the permanent magnet inserted into the magnet insertion hole adjacent to the other direction side It extends can be configured as a rotor. "(Aspect 3), characterized in.
Further, “the rotor according to any one of aspects 1 to 3, wherein the first magnet portion and the second magnet portion of the permanent magnet are magnetized along a circumferential direction. (Aspect 4).
Further, “in the rotor according to any one of aspects 1 to 3, the first magnet portion of the permanent magnet is magnetized along the circumferential direction, and the second magnet portion is along the radial direction. The rotor is characterized by being magnetized. ”(Aspect 5).
Further, “a rotor core, a magnet insertion hole formed in the rotor core, and a permanent magnet inserted into the magnet insertion hole, and the magnet insertion hole as viewed in a cross section perpendicular to the axial direction, The permanent magnet extends along the radial direction, and a plurality of the permanent magnets are provided along the circumferential direction. The rotor has a d-axis and a q-axis defined by the permanent magnet. The first side wall and the second side wall, which are arranged on one side and the other side along the circumferential direction and extend in parallel with the q axis, are arranged on the outer circumferential side and the inner circumferential side along the radial direction, An outer peripheral wall and an inner peripheral wall extending along the circumferential direction, a first oblique wall connected to the first side wall and the inner peripheral wall, a second wall connected to the second side wall and the inner peripheral wall. The first inclined wall is formed by inserting a magnet having the first inclined wall. A d-axis defined by a permanent magnet inserted into the hole and a permanent magnet inserted into the magnet insertion hole adjacent to one side along the circumferential direction with respect to the magnet insertion hole having the first inclined wall The second inclined wall is formed in a circumferential direction with respect to the permanent magnet inserted into the magnet insertion hole having the second inclined wall and the magnet insertion hole having the second inclined wall. The first of the magnet insertion holes is formed in parallel with the d-axis defined by the permanent magnet inserted into the magnet insertion hole adjacent to the other direction side along the circumferential direction and adjacent to the circumferential direction. A bridge portion is formed by the inclined wall and the second inclined wall of the other magnet insertion hole. ”(Aspect 6).
Further, the rotor according to any one of aspects 1 to 6, wherein the outer peripheral surface of the rotor core is a first outer peripheral surface intersecting with the d axis when viewed in a cross section perpendicular to the axial direction, and the q axis Second outer peripheral surfaces intersecting each other are alternately connected, the first outer peripheral surface is formed in an arc shape having a center of curvature on the d-axis, and the second outer peripheral surface is q A rotor having a center of curvature on an axis and having a larger radius of curvature than the radius of curvature of the first outer peripheral surface. ”(Aspect 7) .
Further, it can be configured as “a rotor according to any one of aspects 1 to 7, wherein a ferrite magnet is used as a permanent magnet” (aspect 8).
Further, “a stator and a rotor supported rotatably with respect to the stator, the stator having a stator core and a stator winding, and the rotor being a rotor core A permanent magnet electric motor having a magnet insertion hole formed in the rotor core and a permanent magnet inserted in the magnet insertion hole, wherein the rotation according to any one of aspects 1 to 8 is used as the rotor. A permanent magnet motor characterized in that a child is used. ”(Mode 1).

DESCRIPTION OF SYMBOLS 10 Permanent magnet motor 20 Stator 30 Stator core 40 Stator winding 50 Rotor 60 Rotary shaft 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 Rotor core 101, 201, 301, 401, 501, 601, 701, 801, 901, 1001 Outer peripheral surface 102, 202, 302, 402, 502, 602, 702, 802, 902, 1002 Inner peripheral surface 105, 205, 305, 405, 505, 605, 705 , 805, 905, 1005 Outer bridge part 106, 206, 306, 406, 506, 606, 706, 806, 906, 1006 Inner bridge part 111, 112, 211, 212, 311, 312, 311, 411, 412, 511, 512, 611, 612, 711, 712, 811, 812, 91 , 912, 1011 Magnet insertion holes 111a, 211a, 311a, 511a, 911a 911b, 911c Side walls 111d, 111e, 211d, 212e, 311d, 311e, 511d, 511e Intermediate walls 111h, 211h, 311h, 511h, 911h Inner peripheral walls 121, 122, 221, 222, 321, 322, 421, 422, 521, 522, 621, 622, 721, 722, 821, 822, 921, 922, 1021 Permanent magnets 121a, 122a, 221a, 222a, 321a, 322a, 521a, 721a, 722a, 921a Peripheral surfaces 121b, 121c, 122b, 122c, 221b, 221c, 222b, 222c, 321b, 321c, 322b, 322c, 521b, 521c, 521f, 521g, 721b, 721c, 722b, 722c, 921b, 921c side surface 121d 122d, 221d, 222d, 321d, 322d, 521h, 721d, 722d, 921h Peripheral magnet inner peripheral surfaces 301A, 401A, 601A, 701A First outer peripheral surfaces 301B, 401B, 601B, 701B Second outer peripheral surfaces 721e, 722e R surfaces 821f, 822f Tapered surfaces 521d, 521e Intermediate surfaces 911i, 911j Slope walls 921i, 921j Slope

Claims (6)

A rotor core, a magnet insertion hole formed in the rotor core, and a permanent magnet inserted into the magnet insertion hole, the magnet insertion hole and the permanent magnet as viewed in a cross section perpendicular to the axial direction Is a rotor which extends along the radial direction and is provided along the circumferential direction, the d-axis and the q-axis being defined by the permanent magnet,
The magnet insertion hole includes a first portion extending linearly along the q axis, and a second portion provided on the inner peripheral side of the first portion and extending in an arc shape along the circumferential direction. Have
The permanent magnet has a first magnet part inserted into the first part of the magnet insertion hole, and a second magnet part inserted into the second part of the magnet insertion hole,
The side wall on one side along the circumferential direction of the second portion of the magnet insertion hole has a permanent magnet inserted into the magnet insertion hole and one side along the circumferential direction with respect to the magnet insertion hole. Is formed parallel to the d axis defined by the permanent magnet inserted into the magnet insertion hole adjacent to
The side wall on the other direction side in the circumferential direction of the second portion of the magnet insertion hole has a permanent magnet inserted into the magnet insertion hole and the other direction side along the circumferential direction with respect to the magnet insertion hole. Is formed parallel to the d axis defined by the permanent magnet inserted into the magnet insertion hole adjacent to
A bridge portion is formed by the side wall on the one-direction side of the second portion of one magnet insertion hole and the side wall on the other-direction side of the second portion of the other magnet insertion hole among the magnet insertion holes adjacent in the circumferential direction. Has been
The rotor according to claim 1, wherein the first magnet portion and the second magnet portion of the permanent magnet are magnetized along a circumferential direction . The rotor according to claim 1,
The rotor according to claim 1, wherein the first magnet portion and the second magnet portion of the permanent magnet are formed by separate first and second permanent magnets, respectively. The rotor according to claim 1 or 2,
The first portion of the magnet insertion hole is disposed on one side and the other side along the circumferential direction with respect to the q axis, and includes a first side wall and a second side wall extending in parallel with the q axis. Have
The second portion of the magnet insertion hole has a third side wall and a fourth side wall disposed on one side and the other side along the circumferential direction with respect to the q axis,
The third side wall is defined by a permanent magnet inserted into the magnet insertion hole and a permanent magnet inserted into a magnet insertion hole adjacent to the magnet insertion hole on one side along the circumferential direction. The fourth side wall is inserted into the permanent magnet inserted into the magnet insertion hole and the magnet insertion hole adjacent to the magnet insertion hole on the other direction side along the circumferential direction. The rotor extends in parallel with the d-axis defined by the permanent magnet. It is a rotor as described in any one of Claims 1-3 ,
The outer circumferential surface of the rotor core is formed by alternately connecting a first outer circumferential surface intersecting with the d axis and a second outer circumferential surface intersecting with the q axis when viewed in a cross section perpendicular to the axial direction. The first outer peripheral surface is formed in an arc shape having a center of curvature on the d-axis, the second outer peripheral surface has a center of curvature on the q-axis, and the curvature of the first outer peripheral surface is A rotor characterized by being formed into an arc shape having a radius of curvature larger than the radius. It is a rotor as described in any one of Claims 1-4 ,
A rotor characterized in that a ferrite magnet is used as a permanent magnet. A stator, and a rotor supported rotatably with respect to the stator, the stator having a stator core and a stator winding, the rotor including the rotor core, and A permanent magnet motor having a magnet insertion hole formed in a rotor core and a permanent magnet inserted into the magnet insertion hole, wherein the rotor is the rotor according to any one of claims 1 to 5. A permanent magnet electric motor characterized by using a rotor.

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