JP2014171340A5 - - Google Patents

Description

Rotor and permanent magnet motor

  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 600 shown in FIG. FIG. 9 is a cross-sectional view of the rotor core 600 viewed from a direction perpendicular to the axial direction. The rotor core 600 shown in FIG. 9 has a plurality of magnet insertion holes 611 extending linearly from the rotation center O along the radial direction along the circumferential direction. A permanent magnet 621 is inserted into the magnet insertion hole 611. The magnet insertion hole 611 and the permanent magnet 621 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. 9, the magnetic flux is short-circuited through the inner peripheral surface portion of the rotor core. As a method for preventing this magnetic flux short circuit, it is conceivable to reduce the interval W on the inner peripheral surface side of the magnet insertion holes 611 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 short-circuiting of the magnetic flux cannot be sufficiently prevented.
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. The permanent magnet is 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 insertion hole and the second magnet insertion hole which are arranged on one side and the other side along the circumferential direction with the q axis interposed therebetween and extend linearly along the q axis. Thus, a magnet insertion hole group is configured, and a plurality of magnet insertion hole groups are arranged along the circumferential direction. Typically, the first magnet insertion hole (second magnet insertion hole) is disposed on the outer peripheral side and the inner peripheral side along the radial direction, and has an outer peripheral wall extending linearly along the circumferential direction and The inner peripheral wall is formed by a first side wall and a second side wall that are arranged on one side and the other side along the circumferential direction and extend linearly in parallel to the q axis.
Moreover, the permanent magnet comprises the permanent magnet group by the 1st permanent magnet inserted in the 1st magnet insertion hole, and the 2nd permanent magnet inserted in the 2nd magnet insertion hole.
And the magnet insertion hole group adjacent to the circumferential direction is formed so that a 1st bridge part may be formed between adjacent magnet insertion hole groups. The first magnet insertion hole and the second magnet insertion hole are formed with a second bridge portion between the first magnet insertion hole and the second magnet insertion hole constituting the same magnet insertion hole group. It is formed so that. The 1st bridge part and the 2nd bridge part are formed so that the short circuit of magnetic flux can be controlled.
In the present invention, since a plurality of magnet insertion hole groups extending along the radial direction are arranged along the circumferential direction, the magnet surface area can be increased. In addition, a first bridge portion is formed between two magnet insertion hole groups adjacent in the circumferential direction, and a first magnet insertion hole and a second magnet insertion hole that constitute the same magnet insertion hole group, Since the 2nd bridge | bridging part is formed between these, the intensity | strength with respect to a centrifugal force can be raised. Thereby, the space | interval between magnet insertion hole groups can be made small, and it can prevent that a magnetic flux short-circuits via the part between adjacent magnet insertion hole groups of a rotor core. Therefore, 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 a different form of one invention, the first magnet insertion hole is disposed on one side and the other side along the circumferential direction, and extends in parallel with the q axis. The outer peripheral wall and the inner peripheral wall are disposed on the outer peripheral side and the inner peripheral side along the radial direction and extend along the circumferential direction, and the first inclined wall is formed. The first slant wall of the first magnet insertion hole is connected to the first side wall and the inner peripheral wall that are arranged on one side along the circumferential direction among the first side wall and the second side wall. Yes. Further, the first inclined wall of the first magnet insertion hole includes the first permanent magnet and the second inserted into the magnet insertion hole group including the first magnet insertion hole having the first inclined wall. A d-axis defined by a permanent magnet and a first permanent magnet and a second permanent magnet that are inserted into a magnet insertion hole group adjacent to the magnet insertion hole group in one direction along the circumferential direction; They are formed in parallel.
The second magnet insertion hole is disposed on one side and the other side along the circumferential direction, and extends along the radial direction with the first side wall and the second side wall extending parallel to the q axis. The outer peripheral wall and the inner peripheral wall are arranged on the outer peripheral side and the inner peripheral side and extend along the circumferential direction, and are formed by a second inclined wall. The second inclined wall of the second magnet insertion hole is connected to the second side wall and the inner peripheral wall, which are arranged on the other side of the first side wall and the second side wall along the circumferential direction. Yes. Further, the second inclined wall of the second magnet insertion hole includes the first permanent magnet and the second inserted into the magnet insertion hole group including the second magnet insertion hole having the second inclined wall. A d-axis defined by a permanent magnet and a first permanent magnet and a second permanent magnet inserted in a magnet insertion hole group adjacent to the magnet insertion hole group on the other side in the other direction along the circumferential direction. Are formed in parallel.
And the 1st slant wall of the 1st magnet insertion hole which comprises one magnet insertion hole group among the two magnet insertion hole groups adjacent to the circumferential direction, and the 2nd which comprises the other magnet insertion hole group A first bridge portion is formed by the second inclined wall of the magnet insertion hole.
In this embodiment, since a bridge portion having a width and a length that extends along the d-axis (radial direction) and can suppress a short circuit of magnetic flux is formed between the magnet insertion hole groups, the rotor core The magnetic flux can be effectively prevented from being short-circuited through the portion between the magnet insertion hole groups. Further, the first inclined wall of the first magnet insertion hole forming the second bridge portion and the second inclined wall of the second magnet insertion hole are formed in parallel to the d-axis (radial direction). The strength due to centrifugal force can be effectively increased.

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 prevents a short circuit of the magnetic flux.
In this embodiment, since the second outer circumferential surface of the rotor core is substantially parallel to the outer peripheral wall of the magnet insertion holes, substantially the distance between the second outer peripheral surface and the outer peripheral wall of the magnet insertion holes of the rotor core Will be equal. Thereby, the width | variety of a 1st bridge part can be made small, preventing the fall of the intensity | strength with respect to a centrifugal force, and the 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 effects of the above-described inventions.

  By using the rotor and permanent magnet motor of the present invention, it is possible to suppress a short circuit of magnetic flux while preventing 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 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. 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. 2 is a cross-sectional view of the rotor core 100 used in the permanent magnet motor 10 of the first embodiment as viewed from a direction perpendicular to the axial direction. FIG. 3 is a partially enlarged view of FIG. FIG.
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 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 first is arranged on one side along the circumferential direction with the q axis in between and extends linearly along the q axis. The magnet insertion holes 111 and the second magnet insertion holes 112 arranged in the other direction along the circumferential direction across the q axis and extending linearly along the q axis constitute a magnet insertion hole group. ing. A plurality of magnet insertion hole groups are arranged along the circumferential direction.
The first magnet insertion hole 111 is formed by an outer peripheral wall 111a, a first side wall 111b, a second side wall 111c, and an inner peripheral wall 111d. 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 along the circumferential direction. The first side wall 111b and the second side wall 111c are disposed on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The inner peripheral wall 111d is disposed on the inner peripheral side (rotation center O side) along the radial direction, and extends linearly along the circumferential direction. Similarly to the first magnet insertion hole 111, the second magnet insertion hole 112 is also formed by an outer peripheral wall 112a, a first side wall 112b, a second side wall 112c, and an inner peripheral wall 112d.

In addition, the first permanent magnet 121 inserted into the first magnet insertion hole 111 and the second permanent magnet 122 inserted into the second magnet insertion hole 112 extend linearly along the q axis. .
The first permanent magnet 121 is formed by an outer peripheral surface 121a, a first side surface 121b, a second side surface 121c, and an inner peripheral surface 121d. The outer peripheral surface 121a is arrange | positioned at the outer peripheral side (outer peripheral surface 101 side) along a radial direction, and is extended linearly along the circumferential direction. The first side surface 121b and the second side surface 121c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The inner peripheral surface 121d is disposed on the inner peripheral side (rotation center O side) along the radial direction, and extends linearly along the circumferential direction. Similarly to the first permanent magnet 121, the second permanent magnet 122 is also formed by an outer peripheral surface 122a, a first side surface 122b, a second side surface 122c, and an inner peripheral surface 122d.
The outer peripheral surface 121a, the first side surface 121b, the second side surface 121c, and the inner peripheral surface 121d of the first permanent magnet 121 are the outer peripheral wall 111a, the first side wall 111b, the second peripheral surface 121d of the first magnet insertion hole 111. It arrange | positions in the position which opposes the side wall 111c and the internal peripheral wall 111d. The outer peripheral surface 122a, the first side surface 122b, the second side surface 122c, and the inner peripheral surface 122d of the second permanent magnet 122 are the outer peripheral wall 112a, the first side wall 112b, and the second inner surface 122d of the second magnet insertion hole 112. It arrange | positions in the position which opposes the side wall 112c and the internal peripheral wall 112d. The first permanent magnet 121 and the second permanent magnet 122 constitute a permanent magnet group.

The first permanent magnet 121 and the second permanent magnet 122 are magnetized (magnetized) so that adjacent main magnetic poles have different polarities.
In the present embodiment, as shown in FIG. 3, the first permanent magnet inserted into the first magnet insertion hole 111 and the second magnet insertion hole 112 constituting the same magnet insertion hole group. 121 and the second permanent magnet 122 are magnetized to have the same polarity along the circumferential direction. For example, the first side surface 121b of the first permanent magnet 121 and the first side surface 122b of the second permanent magnet 122 become N poles, and the second side surface 121c of the first permanent magnet 121 and the second permanent magnet. The second side surface 122c of 122 is magnetized so as to be an S pole. That is, in the first permanent magnet and the second permanent magnet constituting the same permanent magnet group, one side surface along the circumferential direction becomes one pole, and the other side surface along the circumferential direction. Is magnetized along the circumferential direction so as to be the other pole.
Moreover, about the 1st permanent magnet 121 and the 2nd permanent magnet 122 which comprise the permanent magnet group adjacent to the circumferential direction, the surface (for example, one permanent magnet group is comprised) which opposes along the circumferential direction. The first side surface 121b of the first permanent magnet 121 and the second side surface 121c of the second permanent magnet 122 constituting the other permanent magnet group are magnetized along the circumferential direction so as to have the same pole. The That is, one surface along the circumferential direction of one permanent magnet group of the permanent magnet groups adjacent in the circumferential direction and the other surface along the circumferential direction of the other permanent magnet group have the same pole. Is magnetized.
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, a bridge portion 105 is formed between the outer peripheral wall 111 a of the first magnet insertion hole 111 and the outer peripheral wall 112 a of the second magnet insertion hole 112 and the outer peripheral surface 101 of the rotor core 100. Yes.
By this bridge portion 105, a portion of the rotor core 100 between the first magnet insertion hole 111 and the outer peripheral surface 101 of the rotor core 100 and the second magnet insertion hole 112 and the outer peripheral surface 101 of the rotor core 100 are provided. The magnetic flux can be prevented from being short-circuited through the portion between the two.
The bridge unit 105 corresponds to the “third bridge unit” of the present invention.

A bridge portion 106 is formed between the magnet insertion hole groups adjacent in the circumferential direction. That is, the first side wall 111b of the first magnet insertion hole 111 constituting the one magnet insertion hole group among the magnet insertion hole groups adjacent in the circumferential direction (the first magnet on the one direction side along the circumferential direction). The first side surface on one side along the circumferential direction of the insertion hole) and the second side wall 112c of the second magnet insertion hole 112 constituting the other magnet insertion hole group (the other direction side along the circumferential direction) The bridge portion 106 is formed between the second magnet insertion hole and the second side surface on the other direction side in the circumferential direction.
By this bridge portion 106, between the magnet insertion hole groups adjacent to each other in the circumferential direction of the rotor core 100 (the first magnet insertion hole group constituting one magnet insertion hole group and the first magnet insertion hole group constituting the other magnet insertion hole group). The magnetic flux can be prevented from being short-circuited through the portion between the two magnet insertion holes.
Preferably, the minimum value (minimum width) of the distance along the circumferential direction of the bridge portion 106 is set within a range of 0.35 mm to 0.5 mm.
The bridge unit 106 corresponds to the “first bridge unit” of the present invention.

Further, a bridge portion 107 is formed between the first magnet insertion hole 111 and the second magnet insertion hole 112 constituting the same magnet insertion hole group. That is, the second side wall 111c on the other direction side along the circumferential direction of the first magnet insertion hole 111 on the one direction side along the circumferential direction, and the second magnet insertion hole on the other direction side along the circumferential direction. A bridge portion 107 is formed between the first side wall 112 b on one side along the circumferential direction of the 112.
Since the bridge portion 107 extends along the q axis (radial direction), the strength against centrifugal force is increased. The bridge portion 107 is formed so as to be able to suppress a short circuit of magnetic flux through the bridge portion 107 portion.
Preferably, the interval (width) along the circumferential direction of the bridge portion 107 is set within a range of 0.35 mm to 0.5 mm.
The bridge unit 107 corresponds to the “second bridge unit” of the present invention.

In the present embodiment, since the permanent magnets (permanent magnet group composed of the first permanent magnet 112 and the second permanent magnet 122) are arranged so as to extend along the radial direction, the magnet surface area of the permanent magnets. Can be increased, and the amount of magnetic flux generated from the permanent magnet can be increased.
Further, the first magnet insertion hole (111) and the second magnet insertion hole (112) constitute a magnet insertion hole group, and the first magnet insertion hole (111) and the second magnet insertion hole group constituting the same magnet insertion hole group. A second bridge portion (107) is formed between the magnet insertion holes (112). Thereby, the intensity | strength with respect to the centrifugal force of a rotor core can be raised with the 2nd bridge part (107) and the 1st bridge part (106) formed between adjacent magnet insertion hole groups. In particular, the second side wall (111c) of the first magnet insertion hole (111) forming the second bridge portion (107) and the first side wall (112b) of the second magnet insertion hole (112) are q. Since it extends linearly parallel to the axis (radial direction), the strength against centrifugal force can be further increased. In this case, since the space | interval of a 1st bridge | bridging part (106) can be made small, it can suppress efficiently that a magnetic flux short-circuits via the part between adjacent magnet insertion hole groups.
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.
Similarly to the rotor core 100 of the first embodiment, the rotor core 200 of the present embodiment is arranged on one side and the other side along the circumferential direction with the q axis interposed therebetween, and q A first magnet insertion hole 211 and a second magnet insertion hole 212 that extend linearly along the axis constitute a magnet insertion hole group. A plurality of magnet insertion hole groups are arranged along the circumferential direction.
Further, the first permanent magnet 221 and the second permanent magnet 222 having the same configuration as the permanent magnets 121 and 122 of the first embodiment are provided in the first magnet insertion hole 211 and the second magnet insertion hole 222, respectively. Has been inserted.

In the rotor core 200 of the present embodiment, the shape of the outer peripheral surface 201 of the rotor core 200 is different from the shape of the outer peripheral surface 101 of the rotor core 100 of the first embodiment.
The outer peripheral surface 201 of the rotor core 200 is configured by alternately arranging the first curved portions 201A and the second curved portions 201B when viewed in a cross section perpendicular to the axial direction.
The first curved portion 201A is formed in a first curved shape that intersects the d-axis and protrudes in the outer circumferential direction of the rotor core 200. The second curved line portion 201 </ b> B is formed in a second curved shape that intersects the q axis and protrudes in the outer circumferential direction of the rotor core 200. 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 201B.
The first curved portion 201A corresponds to the “first outer peripheral surface” of the present invention, and the second curved portion 201B corresponds to the “second outer peripheral surface” of the present invention.
In the present embodiment, when the switching portion 201a of the first curved portion (201A) and the second curved portion (201B) 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, the intervals between the outer peripheral wall 211a of the first magnet insertion hole 211 and the outer peripheral wall 212a of the second magnet insertion hole 212 and the second curved portion 201B of the outer peripheral surface 201 of the rotor core 200 become substantially equal. Therefore, the interval between the outer peripheral walls 211a and 212a and the second curved portion 201B can be reduced, and a short circuit of magnetic flux can be suppressed. In addition, when the outer peripheral surface 201 of the rotor core 200 has a circular shape, the distance between both end portions along the circumferential direction of the outer peripheral walls 211a and 212a and the outer peripheral surface 201 is the central portion along the circumferential direction. Is smaller than the distance between the outer peripheral surface 201 and the outer peripheral surface 201. For this reason, it is necessary to design so that the part between the both ends of outer peripheral wall 211a and 212a and the outer peripheral surface 201 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 300 of a rotor according to a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a partially enlarged view of a cross-sectional view of the rotor core 300 of the rotor according to the third embodiment viewed from a direction perpendicular to the axial direction.
In rotor core 300 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) 321 e is formed at the corner of the first permanent magnet 321, and an R surface 322 e is formed at the corner of the second permanent magnet 322. The corners forming the R plane can be selected as appropriate.

A rotor core 400 of a rotor according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a partially enlarged view of a cross-sectional view of a rotor core 400 of the rotor according to the fourth embodiment as viewed from a direction perpendicular to the axial direction.
In the rotor core 400 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 (straight surface) 421f is formed at the corner of the first permanent magnet 421, and a tapered surface 422f is formed at the corner of the second permanent magnet 422. The corners forming the tapered surface can be selected as appropriate.

A rotor core 500 of a rotor according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a partially enlarged view of a sectional view of the rotor core 500 of the rotor according to the fifth embodiment viewed from a direction perpendicular to the axial direction.
In the rotor core 500 of the present embodiment, the shapes of the magnet insertion hole and the permanent magnet are different from the magnet insertion hole and the permanent magnet of the rotor core 100 of the first embodiment.
In the present embodiment, the first magnet insertion hole 511 and the second magnet are arranged on one side and the other side along the circumferential direction and extend linearly along the q axis with the q axis interposed therebetween. A magnet insertion hole group is constituted by the magnet insertion holes 512. A plurality of magnet insertion hole groups are arranged along the circumferential direction.
The first magnet insertion hole 511 is formed by an outer peripheral wall 511a, a first side wall 511b, a second side wall 511c, an inner peripheral wall 511d, and a first inclined wall 511g. The outer peripheral wall 511a is arrange | positioned at the outer peripheral side along radial direction, and is extended linearly along the circumferential direction. The first side wall 511b and the second side wall 511c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The inner peripheral wall 511d is disposed on the inner peripheral side along the radial direction and extends linearly along the circumferential direction. The first inclined wall 511g is connected to the first side wall 511b and the inner peripheral wall 511d (arranged on one side along the circumferential direction), and is parallel to the d axis on one side along the circumferential direction from the q axis. It extends in a straight line.
The second magnet insertion hole 512 is formed by an outer peripheral wall 512a, a first side wall 512b, a second side wall 512c, an inner peripheral wall 512d, and a second inclined wall 512h. The outer peripheral wall 512a is arrange | positioned at the outer peripheral side along radial direction, and is extended linearly along the circumferential direction. The first side wall 512b and the second side wall 512c are arranged on one side and the other side along the circumferential direction, and extend linearly in parallel to the q axis. The inner peripheral wall 512d is disposed on the inner peripheral side along the radial direction, and extends linearly along the circumferential direction. The second inclined wall 512h is connected to the second side wall 512c and the inner peripheral wall 512d (disposed on the other direction side along the circumferential direction), and is parallel to the d axis on the other direction side along the circumferential direction from the q axis. It extends in a straight line.

In addition, the first permanent magnet 521 inserted into the first magnet insertion hole 511 and the second permanent magnet 522 inserted into the second magnet insertion hole 512 extend linearly along the q axis. .
The first permanent magnet 521 is formed by an outer peripheral surface 521a, a first side surface 521b, a second side surface 521c, an inner peripheral surface 521d, and a first inclined surface 521g. The outer peripheral surface 521a is arrange | positioned at the outer peripheral side along radial direction, and is extended linearly along the circumferential direction. The first side surface 521b and the second side surface 521c are disposed on one direction side and the other direction side along the circumferential direction, and extend linearly in parallel to the q axis. The inner peripheral surface 521d is disposed on the inner peripheral side along the radial direction, and extends linearly along the circumferential direction. The first inclined surface 521g is connected to the first side surface 521b and the inner peripheral surface 521d (arranged on one side along the circumferential direction), and is parallel to the d axis on one side along the circumferential direction from the q axis. It extends in a straight line.
The second permanent magnet 522 is formed by an outer peripheral surface 522a, a first side surface 522b, a second side surface 522c, an inner peripheral surface 522d, and a second inclined surface 522h. The outer peripheral surface 522a is disposed on the outer peripheral side along the radial direction, and extends linearly along the circumferential direction. The first side surface 522b and the second side surface 522c are disposed on one direction side and the other direction side along the circumferential direction, and extend linearly in parallel to the q axis. The inner peripheral surface 522d is disposed on the inner peripheral side along the radial direction, and extends linearly along the circumferential direction. The second inclined surface 522h is connected to the second side surface 522c and the inner peripheral surface 522d (arranged on the other direction side along the circumferential direction), and is 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 first permanent magnet 521 and the second permanent magnet 522 are magnetized similarly to the first embodiment.

In the present embodiment, as in the first embodiment, a bridge portion 505 is formed between the first magnet insertion holes 511 and 512 and the outer peripheral surface 501 of the rotor core 500, and adjacent magnet insertion holes. A bridge portion 506 is formed between the groups, and a bridge portion 507 is formed between the first magnet insertion hole 511 and the second magnet insertion hole 512 constituting the same magnet insertion hole group.
In the present embodiment, the bridge portion 506 includes the first slant wall 511g of the first magnet insertion hole 511 that constitutes one of the magnet insertion hole groups adjacent in the circumferential direction, and the other It is formed between the second inclined wall 512h of the second magnet insertion hole 512 constituting the magnet insertion hole group.
Preferably, the bridge portion 506 has an interval (width) H in the circumferential direction set in a range of 0.35 mm to 0.5 mm, and a length (length) L in the radial direction of 1 Set to 5 mm or more.

In the present embodiment, the bridge portion (506) between the magnet insertion hole groups adjacent in the circumferential direction constitutes one magnet insertion hole group among the magnet insertion hole groups adjacent in the circumferential direction. Along the d-axis by the first inclined wall (511g) of the insertion hole (511) and the second inclined wall (512h) of the second magnet insertion hole (512) constituting the other magnet insertion hole group. Are formed to extend linearly. Here, the first slant wall (511g) of the first magnet insertion hole (511) and the second slant wall (512h) of the second magnet insertion hole (512) forming the bridge portion (506) are d. It extends parallel to the axis (radial direction). Thereby, the intensity | strength with respect to the centrifugal force which acts on the rotor core (500) during rotation can be made higher.
Therefore, the width of the bridge portion 506 can be further reduced, and the magnetic flux can be further prevented from being short-circuited through the portion between the magnet insertion hole groups adjacent in the circumferential direction.

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.
In a state where the permanent magnet is inserted in the magnet insertion hole, a configuration having a gap on the outer peripheral surface side from the permanent magnet, a configuration having a gap on the inner peripheral surface side from the permanent magnet, or an outer peripheral side and an inner periphery from the permanent magnet The structure which has a space | gap on the side, ie, the structure which has a space | gap on at least one of an outer peripheral side and an inner peripheral side from a permanent magnet, can also be used. By providing a gap on the inner peripheral surface side, it is possible to suppress the magnetic flux from being short-circuited via the portion on the inner peripheral side from the magnet insertion hole. In addition, by providing a gap on the outer peripheral side, it is possible to suppress the magnetic flux from being short-circuited through a portion on the outer peripheral side from the magnet insertion hole.

DESCRIPTION OF SYMBOLS 10 Permanent magnet motor 20 Stator 30 Stator core 40 Stator winding 50 Rotor 60 Rotating shaft 100, 200, 300, 400, 500, 600 Rotor core 101, 201, 301, 401, 501, 601 Outer surface 102 202, 302, 402, 502, 602 Inner peripheral surface 105, 205, 305, 405, 505 Outer peripheral bridge portion 106, 206, 306, 406, 506, 606 Inner peripheral bridge portion 107, 207, 307, 407, 507 poles Bridge portion 111, 112, 211, 212, 311, 312, 311, 411, 412, 511, 512, 611 Magnet insertion hole 111a, 112a, 211a, 212a, 311a, 312a, 411a, 412a, 511a, 512a Outer peripheral wall 111b, 111c, 112b, 112c, 211b, 211 212b, 212c, 311b, 311c, 312b, 312c, 411b, 411c, 422b, 422c, 511b, 511c, 512b, 512c Side wall 111d, 211d, 311d, 411d, 412d, 511d Inner wall 121, 122, 221, 222, 321 322, 421, 422, 521, 522, 621 Permanent magnets 121a, 122a, 221a, 222a, 321a, 322a, 421a, 422a, 521a, 522a Peripheral magnet outer peripheral surfaces 121b, 121c, 122b, 122c, 221b, 221c, 222b, 222c, 321b, 321c, 322b, 322c, 421b, 421c, 422b, 422c. 521b, 521c, 522b, 522c Side surfaces 121d, 122d, 221d, 222d, 321d, 322d, 421d, 422d, 521d, 522d Permanent magnet inner peripheral surface 201A First outer peripheral surface 201B Second outer peripheral surface 321e, 322e R surface 421f, 422f Tapered surface 511g, 512h Slope wall 521g, 522h Slope

Claims (5)

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 is a first magnet that is arranged on one side and the other side along the circumferential direction across the q axis and extends linearly along the q axis when viewed in a cross section perpendicular to the axial direction. It is constituted as a magnet insertion hole group by the insertion hole and the second magnet insertion hole,
The permanent magnet is configured as a permanent magnet group by a first permanent magnet inserted into the first magnet insertion hole and a second permanent magnet inserted into the second magnet insertion hole,
A side wall of the first magnet insertion hole constituting the magnet insertion hole group on a side facing the second magnet insertion hole, and the first magnet insertion hole group constituting the first magnet insertion hole group. The side wall facing the magnet insertion hole extends parallel to the q axis,
The first bridge portion between the first magnet insertion hole constituting one magnet insertion hole group and the second magnet insertion hole constituting the other magnet insertion hole group among the magnet insertion hole groups adjacent in the circumferential direction. Is formed,
A rotor, wherein a second bridge portion is formed between the first magnet insertion hole and the second magnet insertion hole constituting the same magnet insertion hole group. The rotor according to claim 1,
The first magnet insertion holes are arranged on one side and the other side along the circumferential direction, and extend in parallel to the q axis. The first side wall and the second side wall, and the outer peripheral side along the radial direction And an outer peripheral wall and an inner peripheral wall which are arranged on the inner peripheral side and extend along the circumferential direction, and are formed by the first side wall and the first inclined wall connected to the inner peripheral wall,
The second magnet insertion hole is disposed on one side and the other side along the circumferential direction, and extends in parallel to the q axis. The first side wall and the second side wall, and the outer circumferential side along the radial direction. And an outer peripheral wall and an inner peripheral wall which are arranged on the inner peripheral side and extend along the circumferential direction, and are formed by the second side wall and the second inclined wall connected to the inner peripheral wall,
The first inclined wall includes a first permanent magnet and a second permanent magnet that are inserted into a magnet insertion hole group including a first magnet insertion hole having the first inclined wall, and the magnet insertion hole. Formed parallel to the d-axis defined by the first permanent magnet and the second permanent magnet inserted in the magnet insertion hole group adjacent to the group in the circumferential direction along the circumferential direction;
The second inclined wall includes a first permanent magnet and a second permanent magnet inserted into a magnet insertion hole group including a second magnet insertion hole having the first inclined wall, and the magnet insertion hole. Formed in parallel with the d axis defined by the first permanent magnet and the second permanent magnet inserted into the magnet insertion hole group adjacent to the group along the circumferential direction in the other direction side;
Among the magnet insertion hole groups adjacent to each other in the circumferential direction, the first slant wall of the first magnet insertion hole constituting the first magnet insertion hole group and the second magnet insertion constituting the other magnet insertion hole group. The rotor, wherein the first bridge portion is formed by the second inclined wall of the hole. The rotor according to claim 1 or 2,
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. The rotor according to any one of claims 1 to 3,
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 It is a permanent magnet electric motor which has the magnet insertion hole formed in the rotor core, and the permanent magnet inserted in the said magnet insertion hole, Comprising: As said rotor, It is any one of Claims 1-4. A permanent magnet electric motor characterized by using a rotor.