JP2014113052A - Permanent magnet rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for improving efficiency of a permanent magnet rotating machine by increasing magnetic flux amount.SOLUTION: An external circumferential surface of a rotor 30 is formed of first curved line portions 30a to 30d and second curved line portions 30ab to 30da which have different radius curvature. First magnet housing holes 32a to 32d and second magnet housing holes 34a to 34d are provided on main magnetic pole portions a to d. In this way, intermediate bride portions 36a to 36d, first external circumferential bridge portions 37a1 to 37d1 and second external circumferential bridge portions 37a2 to 37d2 are formed. An external wall 32c1 of the first magnetic housing hole 32c is formed in an arc shape centered at a center point c11. Also, an external wall 34c1 of the second magnet housing hole 34c is formed in the arc shape centered at a center point c21 different from the center point c11.

Description

  The present invention relates to a permanent magnet rotating machine in which a permanent magnet is housed in a magnet housing hole provided in a rotor, and more particularly to a technique for improving the efficiency of the permanent magnet rotating machine.

  As an electric motor for driving a compressor such as an air conditioner (air conditioner) or a refrigerator, an electric motor for driving a vehicle, an in-vehicle device, or the like, a permanent magnet electric motor (“permanent”) in which a permanent magnet is accommodated in a magnet accommodating hole provided in a rotor. It is called a “magnet embedded motor”. This type of permanent magnet motor includes, for example, a stator provided with a tooth portion, and a rotor that is rotatably arranged through a gap between a tooth tip surface of the tooth portion and a tooth. In the rotor, when viewed in a cross section orthogonal to the axial direction of the rotor, main magnetic pole portions and auxiliary magnetic pole portions are alternately arranged in the circumferential direction. The main magnetic pole portion is provided with a magnet accommodation hole, and a permanent magnet is accommodated in the magnet accommodation hole. This permanent magnet motor can utilize both the magnet torque due to the magnetic flux of the permanent magnet accommodated in the magnet accommodation hole of the main magnetic pole part and the reluctance torque due to the saliency of the auxiliary magnetic pole part. In Patent Document 1, a first magnet accommodation hole and a second magnet accommodation hole are arranged on the main magnetic pole portion of a rotor with an intermediate bridge portion interposed therebetween, and the first magnet accommodation hole and the second magnet are arranged. A permanent magnet motor is described in which the housing hole is formed in an arc shape centering on a common center point on the d-axis line of the main magnetic pole portion.

JP 11-285186 A

Conventionally, in a permanent magnet motor, a rare earth magnet having a high magnetic flux density has been used. In particular, neodymium magnets containing Nd (neodymium), Fe (iron), Co (cobalt), B (boron), etc. as constituent components are used. However, since rare earth magnets such as neodymium magnets are expensive, permanent magnet motors using inexpensive permanent magnets, for example, permanent magnet motors using ferrite magnets, etc., whose magnetic flux density is lower than rare earth magnets but are cheaper Development is desired.
In the permanent magnet motor in which the permanent magnet is accommodated in the magnet accommodation hole provided in the main magnetic pole portion of the rotor, the amount of magnetic flux is the outer wall of the magnet accommodation hole (the wall on the side facing the teeth portion of the stator) ) Is determined by the length. For this reason, in order to obtain a permanent magnet motor having the same efficiency as the case where a rare earth magnet having a high magnetic flux density is used using a magnet having a low magnetic flux density such as a ferrite magnet, the length of the outer wall is long. It is necessary to use a rotor provided with a magnet housing hole.
Therefore, the length of the outer wall of the magnet accommodation hole is longer than that of a rotor in which the first magnet accommodation hole and the second magnet accommodation hole formed in a linear shape are arranged in a V shape with the intermediate bridge portion interposed therebetween. It is conceivable to use the rotor described in Patent Document 1. However, even if a permanent magnet electric motor is configured by accommodating a permanent magnet having a low magnetic flux density such as a ferrite magnet in the magnet housing hole of the rotor described in Patent Document 1, a permanent magnet configured using a rare earth magnet having a high magnetic flux density is used. The same efficiency as a magnet motor cannot be obtained. In general, a rare earth magnet having a rectangular cross section is used in terms of manufacturing cost.
The present invention was devised in view of such points, and by increasing the length of the outer wall of the magnet housing hole provided in the main magnetic pole portion, the efficiency of the permanent magnet rotating machine is improved. An object of the present invention is to obtain a permanent magnet rotating machine having the same efficiency as the case of using a rare earth magnet even when a ferrite magnet having a magnetic flux density lower than that of a rare earth magnet is used.

In order to achieve the above object, the first invention of the present invention comprises the following arrangement.
The permanent magnet rotating machine of the present invention includes a stator and a rotor. In the rotor, main magnetic pole portions and auxiliary magnetic pole portions are alternately arranged in the circumferential direction when viewed in a cross section orthogonal to the axial direction. A magnet accommodation hole is provided in the main magnetic pole portion, and a permanent magnet is accommodated in the magnet accommodation hole. At this time, the permanent magnet is accommodated in the magnet accommodation hole so that the polarities of the main magnetic pole portions adjacent in the circumferential direction are reversed. The permanent magnet rotating machine of the present invention is typically configured as a permanent magnet embedded electric motor.
The outer peripheral surface of the rotor is a first curve formed in a first curved shape that intersects with the d-axis line of the main magnetic pole portion and has a protrusion facing outward when viewed in a cross section orthogonal to the axial direction. And a second curved portion formed in a second curved shape that intersects with the q-axis line of the auxiliary magnetic pole portion and has a protruding portion facing outward. The curvature radius of the second curved shape is set larger than the curvature radius of the first curved shape. The “outward direction” represents a direction away from the center point of the rotor (a direction facing the stator) when viewed in a cross section orthogonal to the axial direction of the rotor. “D-axis” represents a line connecting the center point of the rotor and the center point in the circumferential direction of the main magnetic pole portion when viewed in a cross section orthogonal to the axial direction of the rotor, and “q-axis” represents the rotor A line connecting the center point of the rotor and the center point in the circumferential direction of the auxiliary magnetic pole portion is shown in a cross section orthogonal to the axial direction.
When controlling a permanent magnet motor using a sensorless control system that detects a rotor position based on an electromotive force waveform of an electromotive force induced in a stator winding without using a rotor position detection sensor, When the harmonic component contained in the electromotive force waveform increases, optimal control cannot be performed and the efficiency decreases. In the present invention, when the switching portion between the first curved portion and the second curved portion passes through the portion facing the tooth portion, a rapid change in the amount of magnetic flux flowing through the tooth portion can be suppressed. It is possible to prevent an increase in harmonic components contained in the electromotive force waveform of the electromotive force induced in the stator winding due to a sudden change in the amount of magnetic flux flowing through the stator coil. Thereby, when controlling a permanent-magnet motor using a sensorless control system, the fall of the efficiency by the harmonic component contained in an electromotive force waveform can be prevented.
The main magnetic pole part is provided with a first magnet accommodation hole and a second magnet accommodation hole. An intermediate bridge portion is formed between the first magnet accommodation hole and the second magnet accommodation hole by the first magnet accommodation hole and the second magnet accommodation hole, and the outer circumference of the first magnet accommodation hole and the rotor A first outer bridge portion is formed between the surfaces, and a second outer bridge portion is formed between the second magnet housing hole and the outer peripheral surface of the rotor. In the present invention, the first and second magnet housing holes have an outer wall that is concave outward, an inner wall that is convex inward, and a center when viewed in a cross section orthogonal to the axial direction of the rotor. Side wall, outer peripheral surface side wall. The “outer wall” and “inner wall” are the walls on both sides along the longitudinal direction that are closer to the farthest from the center of the rotor, as viewed in the cross section perpendicular to the axial direction of the rotor. Represents the wall. “Center-side wall” represents a wall (a wall forming an intermediate bridge portion) disposed at a position facing another magnet housing hole provided in the main magnetic pole portion. The “wall” represents a wall (a wall forming the first or second outer peripheral bridge portion) disposed at a position facing the outer peripheral surface of the rotor. The strength of the rotor can be increased by the intermediate bridge portion and the first and second outer peripheral bridge portions.
The outer wall and the inner wall of the first magnet housing hole formed between the intermediate bridge portion and the first outer peripheral bridge portion are formed in an arc shape centered on the first curvature center point. . Further, the outer wall of the second magnet housing hole formed between the intermediate bridge portion and the second outer peripheral bridge portion is centered on a second curvature center point different from the first curvature center point, respectively. It is formed in an arc shape having a radius equal to the radius of the outer wall and the inner wall of the first magnet housing hole. The configuration “formed in an arc shape” includes a mode in which the arc shape is formed. The positions of the first curvature center point and the second curvature center point are such that the length of the outer wall of the first magnet accommodation hole and the outer wall of the second magnet accommodation hole is the same as that of the rotor having the same diameter. When the outer wall of the first magnet housing hole and the outer wall of the second magnet housing hole are formed in an arc shape centered on the common center of curvature on the d-axis, using a thick permanent magnet The outer wall of the first magnet housing hole and the outer wall of the second magnet housing hole are set to be longer than the maximum value. The positions of the first curvature center point and the second curvature center point are the size of the rotor, the width of the intermediate bridge portion and the first and second bridge portions, and the size of the first and second magnet housing holes. Determined by etc.
The first magnet housing hole has an outer surface formed in an arc shape corresponding to the arc shape of the outer wall of the first magnet housing hole, and an arc shape of the inner wall of the first magnet housing hole. A first permanent magnet having an inner surface formed in a corresponding arc shape is accommodated. The second magnet housing hole includes an outer surface formed in an arc shape corresponding to the arc shape of the outer wall of the second magnet housing hole, and an arc of the inner wall of the second magnet housing hole. A second permanent magnet having an inner surface formed in an arc shape corresponding to the shape is accommodated.
A first curvature center point and a second curvature that are different from each other in the arc shape of the outer wall and the inner wall of the first magnet accommodation hole and the arc shape of the outer wall and the inner wall of the second magnet accommodation hole, respectively. Since it is formed in the circular arc shape centering on the center point, the outer wall and the inner wall of the first magnet housing hole and the second wall are set by setting the first curvature center point and the second curvature center point. The length of the outer wall and the inner wall of the magnet housing hole can be increased. Thereby, the amount of magnetic flux can be increased and the efficiency can be improved. In addition, the amount of magnetic flux from the first magnet housing hole and the amount of magnetic flux from the second magnet housing hole become substantially equal, and pulsation of the magnetic flux amount can be prevented. Further, the thickness of the permanent magnet can be made constant, and variations in demagnetization characteristics can be prevented. Further, the reluctance torque by the rotor core between the inner wall of the first magnet housing hole and the rotating shaft insertion hole and between the inner wall of the second magnet housing hole and the rotating shaft insertion hole becomes uniform, and cogging is achieved. Torque can be reduced. Thereby, generation | occurrence | production of the sound and vibration by a cogging torque can be reduced.
In the present invention, the outer peripheral surface of the rotor is formed by the first curved portion and the second curved portion having different radii of curvature, and the first magnet receiving hole and the second magnet receiving hole provided in the main magnetic pole portion. Efficiency is improved by using the structure which lengthens the length of the outer wall of. Thereby, for example, even when a ferrite magnet having a magnetic flux density lower than that of the rare earth magnet is used, the same efficiency as that when the rare earth magnet is used can be obtained.

  In the second invention of the present invention, the first curved portion is formed in an arc shape centered on the center of curvature on the d-axis, and the second curved portion is centered on the center of curvature on the q-axis. It is formed in an arc shape. Thereby, a 1st curve part and a 2nd curve part can be formed easily.

  In the third invention of the present invention, the first curved portion is formed in an arc shape with the center point of the rotor as the center point of curvature, and the second curved portion is the second outer peripheral surface from the center point of the rotor. Are formed in a circular arc shape having a center of curvature at a point separated in the opposite direction. Thereby, when the switching portion between the first curved portion and the second curved portion passes through the portion facing the teeth portion of the stator, the amount of magnetic flux flowing through the teeth portion is more effectively changed. Therefore, the efficiency can be further improved.

In the fourth aspect of the present invention, the set of the first magnet accommodation hole and the second magnet accommodation hole is provided in multiple layers. The “provided in multiple layers” configuration corresponds to a configuration in which a plurality of sets of first magnet accommodation holes and second magnet accommodation holes constituting each layer are provided in the radial direction of the rotor. The outer wall and the inner wall of the first magnet accommodation hole of each layer are formed in an arc shape centering on the first curvature center point, and the outer wall and the inner wall of the second magnet accommodation hole of each layer are formed. Is formed in an arc shape centered on the second center of curvature.
By adopting a multilayer structure, the reluctance torque due to the rotor core between the layers can be used, so that the efficiency can be further improved. In addition, since the multi-layer structure allows the amount of magnetic flux flowing through the teeth portion to change stepwise when the switching portion between the main magnetic pole portion and the auxiliary magnetic pole portion passes through the portion facing the teeth portion of the stator, the teeth portion It is possible to prevent the magnetic flux flowing through the abrupt change.

  By using the first to fourth inventions, the amount of magnetic flux can be increased to improve the efficiency. Thereby, even when a ferrite magnet having a magnetic flux density lower than that of the rare earth magnet is used, a permanent magnet rotating machine having the same efficiency as that when the rare earth magnet is used can be obtained.

It is sectional drawing which looked at 1st Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 1st Embodiment from the direction orthogonal to an axial direction. It is the elements on larger scale of FIG. It is a figure explaining the magnetic orientation direction of the permanent magnet of 1st Embodiment. It is a figure explaining the effect | action of 1st Embodiment. It is a figure explaining the effect | action of a prior art. It is sectional drawing which looked at the rotor of 2nd Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 3rd Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 4th Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 5th Embodiment from the direction orthogonal to an axial direction.

Embodiments of the present invention will be described below with reference to the drawings.
A first embodiment of the present invention is shown in FIGS. In the first embodiment, the present invention is referred to as a permanent magnet motor in which a permanent magnet is accommodated in a magnet accommodation hole provided in a main magnetic pole portion of a rotor ("embedded permanent magnet motor"). ). 1 is a cross-sectional view of the permanent magnet motor 10 according to the first embodiment viewed from a direction orthogonal to the axial direction, and FIG. 2 is a cross-section of the rotor 30 viewed from a direction orthogonal to the axial direction. FIG. In addition, the rotor 30 has shown the case where the number of magnetic poles is 4 (the number of pole pairs is 2).
The permanent magnet motor 10 according to the present embodiment includes a stator 20 and a rotor 30.
The stator 20 is constituted by, for example, a stator core formed by stacking electromagnetic steel plates. The stator 20 has a yoke portion 21 and a teeth portion 22. A slot 23 is formed by the tooth portion 22, and a stator winding is accommodated in the slot 23 by a distributed winding method or a concentrated winding method. As shown in FIG. 3, the tooth portion 22 includes a base portion 22a and tooth end portions 22b and 22c provided on both sides of the base portion 22a in the rotational direction. A tooth tip surface 22d is formed by the surface of the base portion 22a and the teeth end portions 22b and 22c on the side facing the rotor 30. The rotor 30 is rotatably arranged in a state where a gap (gap) between the outer peripheral surface of the rotor 30 and the tooth tip surface 22d of the teeth portion 22 of the stator 20 is set to g.

The rotor 30 is constituted by a rotor core 31 formed by laminating electromagnetic steel plates, for example. The rotor core 31 is formed with a rotation shaft insertion hole 40 into which a rotation shaft is inserted, and main magnetic pole portions a, b, c, d and auxiliary magnetic pole portions ab, bc, cd, da are arranged in the circumferential direction. Alternatingly arranged. The rotating shaft is inserted into the rotating shaft insertion hole 40 by, for example, a press-fitting method or a shrinking method.
The rotor core 31 is formed with caulking pin insertion holes 38a to 38d into which caulking pins for fixing the laminated electromagnetic steel plates are inserted. As the caulking pin, it is preferable to use a caulking pin formed of a magnetic material.

The outer peripheral surface of the rotor core 31 (hereinafter referred to as “rotor 30”) is supplemented with first curved portions (first outer peripheral portions) 30a, 30b, 30c, 30d corresponding to the main magnetic pole portions a to d. The second curved portions (second outer peripheral portions) 30ab, 30bc, 30cd, and 30da corresponding to the magnetic pole portions ab to da are alternately arranged.
The first curved portions 30a to 30d intersect a line (hereinafter referred to as “d-axis”) connecting the center point O of the rotor 30 and the center point in the circumferential direction of the main magnetic pole portions a to d, and the protrusions are outward. It is formed in the 1st curve shape which is suitable for. The second curved portions 30ab to 30da intersect a line (hereinafter referred to as “q-axis”) connecting the center point O of the rotor 30 and the center point in the circumferential direction of the auxiliary magnetic pole portions ab to da, and the protrusions are It is formed in a second curved shape that faces outward. The curvature radius [Rq] of the second curve shape of the second curve portions 30ab to 30da is set larger than the curvature radius [Rd] of the first curve shape of the first curve portions 30a to 30d. (Rq> Rd). The first curve portions 30a to 30d and the second curve portions 30ab to 30da are connected at connection points 30a1 to 30d1 and 30a2 to 30d2. The description “outward direction” represents a direction away from the center point of the rotor.
In the present embodiment, the first curved portions 30 a to 30 d are formed in an arc shape having a radius [Rd] with the center point O of the rotor 30 as the center. The second curved line portions 30ab to 30da are arcs having a radius [Rq] centered on a point on the q axis that is away from the center point O of the rotor 30 in the opposite direction to the second curved line portions 30ab to 30da. It is formed into a shape. FIG. 1 shows the center point (curvature center point) Pab of the arc shape of the second curve portion 30ab, and FIG. 2 shows the center point (curvature center point) Pbc of the arc shape of the second curve portion 30bc. The arc-shaped center point (curvature center point) Pcd of the second curved portion 30cd is shown.
The opening angle θ of the first curved portions 30a to 30d is set in a range where high efficiency can be obtained.
The curved shapes of the first curved portions 30a to 30d and the second curved portions 30ab to 30da may be a projecting shape such as an arc shape or an elliptical shape. Further, the positions of the center points (curvature center points) of the first curved portions 30a to 30d and the center points (curvature center points) of the second curved portions 30ab to 30da can be changed as appropriate. For example, the center point of the first curve portions 30a to 30d may be set to a point on the d-axis line that is away from the center point O of the rotor 30 in the direction of the first curve portions 30a to 30d.
In the present embodiment, the first curve portions 30a to 30d correspond to the “first curve portion” of the present invention, and the center point O of the rotor 30 corresponds to the “first curve-shaped first of the present invention”. [Rd] corresponds to the “curvature radius of the first curved shape” of the present invention. The second curve portions 30ab-30da correspond to the “second curve portion” of the present invention, and the points Pab, Pbc, Pcd correspond to the “second curvature center point of the second curve shape” of the present invention. Correspondingly, [Rq] corresponds to the “curvature radius of the second curved shape” of the present invention.

  When the first curve portions 30 a to 30 d and the second curve portions 30 ab to 30 da are switched (portions 30 a 1 to 30 d 1 and 30 a 2 to 30 d 2) pass through a portion facing the teeth portion 22, the teeth portion 22. The amount of magnetic flux flowing through the coil can be prevented from changing suddenly, and an increase in harmonic components contained in the electromotive force waveform of the electromotive force induced in the stator winding can be prevented. Thus, for example, without using a rotor position detection sensor, a permanent magnet motor can be used using a sensorless control device that detects a rotor position based on an electromotive force waveform of an electromotive force induced in a stator winding. In the case of control, it is possible to prevent a decrease in rotor position detection accuracy due to harmonic components included in the electromotive force waveform. Therefore, it is possible to prevent a decrease in efficiency due to a decrease in rotor position detection accuracy. Further, since a sufficient electromotive force can be induced in the stator winding, it is not necessary to increase the number of turns of the stator winding. Thereby, the fall of the efficiency by the copper loss of a stator winding | coil can be prevented.

The main magnetic pole portions a to d are provided with first magnet housing holes 32a to 32d and second magnet housing holes 34a to 34d. First permanent magnets 33a to 33d are accommodated in the first magnet accommodation holes 32a to 32d, and second permanent magnets 35a to 35d are accommodated in the second magnet accommodation holes 34a to 34d. The first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) are accommodated in the first magnet accommodation holes 32a to 32d (second magnet accommodation holes 34a to 34d) by, for example, a gap fitting method. The The first permanent magnets 33a to 33d and the second permanent magnets 35a to 35d are magnetized so that the polarities of the main magnetic pole portions a to d adjacent in the circumferential direction are opposite to each other. In FIG. 2, the first permanent magnet 33 a and the second permanent magnet 35 a of the main magnetic pole part a, and the first permanent magnet 33 c and the second permanent magnet 35 c of the main magnetic pole part c are N poles on the outer peripheral surface side, and the center A main magnetic pole part b, which is magnetized so that the side becomes an S pole, and is adjacent to the main magnetic poles a and c, a first permanent magnet 33b and a second permanent magnet 35b. The first permanent magnet 33d and the second permanent magnet 35d of the main magnetic pole portion d are magnetized so that the outer peripheral surface side is the S pole and the center side is the N pole.
In the present embodiment, the first magnet housing holes 32a to 32d include outer walls (outer walls) 32a1 to 32d1, inner walls (inner walls) 32a2 to 32d3, outer peripheral surface walls (outer peripheral end walls) 32a3. 32d3 and the center side wall (center side end wall) 32a4 to 32d4. Similarly, the second magnet housing holes 34a to 34d are formed on the outer walls (outer walls) 34a1 to 34d1, the inner walls (inner walls) 34a2 to 34d2, the outer peripheral side walls (outer end walls) 34a3 to 34d3, the center. Side walls (center side end walls) 34a4 to 34d4 are formed. The “outer wall” and “inner wall” are the center points of the rotor 30 (rotor core 31) among the walls on both sides along the longitudinal direction when the rotor 30 is viewed in a cross section perpendicular to the axial direction. The far wall from O and the near wall are shown. Further, the “outer peripheral wall” and “center wall” are walls arranged at positions facing the outer peripheral surface of the rotor 30 and other magnet housing holes provided in the main magnetic pole portions a to d. The wall arrange | positioned in the position which opposes is represented. The shape of the cross section orthogonal to the axial direction of the first permanent magnets 33a to 33d is orthogonal to the axial direction of the first magnet housing holes 32a to 32d to the extent that it can be accommodated in the first magnet housing holes 32a to 32d. It is formed in a shape corresponding to the shape of the cross section. Similarly, the shape of the cross section orthogonal to the axial direction of the second permanent magnets 35a to 35d is such that the second magnet accommodating holes 34a to 34d can be accommodated in the second magnet accommodating holes 34a to 34d. It is formed in a shape corresponding to the shape of the cross section orthogonal to. Typically, the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) are first magnet accommodation holes 32a to 32d (second magnet accommodation) as viewed in a cross section orthogonal to the axial direction. Hole 34a-34d) is formed in a shape corresponding to the outer surface 32a1-32d1 (34a1-34d1) corresponding to the outer wall 32a1-32d1 (34a1-34d1) and the inner wall 32a2-32d2 (34a2-34d2). Corresponding to the inner side surface, the outer peripheral surface side surface formed in a shape corresponding to the outer peripheral surface side walls 32a3 to 32d3 (34a3 to 34d3), and the central side walls 32a4 to 32d4 (34a4 to 34d4). It has a central surface formed in a shape.
In the present embodiment, in order to increase the amount of magnetic flux, the walls 32a3 to 32d3 (34a3 to 34d3) on the outer peripheral surface side of the first magnet housing holes 32a to 32d (second magnet housing holes 34a to 34d), the first The surface on the outer peripheral surface side of the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) accommodated in the one magnet accommodation holes 32a to 32d (second magnet accommodation holes 34a to 34d) is rotated. It is formed in parallel (including substantially parallel) to the outer peripheral surface of the child core 31 (rotor 30). Further, the walls 32a4 to 32d4 (34a4 to 34d4) on the center side of the first magnet housing holes 32a to 32d (second magnet housing holes 34a to 34d), the first magnet housing holes 32a to 32d (second magnet). Center-side surfaces of the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) accommodated in the accommodation holes 34a to 34d) are formed in parallel (including substantially parallel) to the d axis. .
About the shape of the cross section orthogonal to the axial direction of 1st magnet accommodation hole 32a-32d (2nd magnet accommodation hole 34a-34d) and 1st permanent magnet 33a-33d (2nd permanent magnet 35a-35d). It will be described later.

In the rotor core 31, intermediate bridge portions 36a to 36d are formed between the first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d, and the first magnet housing holes 32a to 32d are formed. First outer peripheral bridge portions 37a1 to 37d1 are formed between the outer peripheral surface of the rotor 30 (the second curved portions 30ab to 30da described above), and the outer periphery of the second magnet housing holes 34a to 34d and the rotor 30. Second outer peripheral bridge portions 37a2 to 37d2 are formed between the surfaces (the second curved portions 30ab to 30da described above). That is, the intermediate bridge portions 36a to 36d are formed by the central walls 32a4 to 32d4 of the first magnet housing holes 32a to 32d and the central walls 34a4 to 34d4 of the second magnet housing holes 34a to 34d. First outer peripheral bridge portions 37a1 to 37d1 are formed by walls 32a3 to 32d3 on the outer peripheral surface side of the magnet housing holes 32a to 32d and the outer peripheral surface of the rotor 30, and the outer peripheral surface side of the second magnet housing holes 34a to 34d. The second outer peripheral bridge portions 37 a 2 to 37 d 2 are formed by the walls 34 a 3 to 34 d 3 and the outer peripheral surface of the rotor 30.
The strength of the rotor 30 is increased by the intermediate bridge portions 36a to 36d, the first outer peripheral bridge portions 37a1 to 37d1, and the second outer peripheral bridge portions 37a2 to 37d2.

Next, the configuration of the first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d will be described.
First, the structure of the magnet accommodation hole of the conventional permanent magnet motor described in Patent Document 1 will be described with reference to FIG. FIG. 6 is a cross-sectional view of a rotor 830 of a conventional permanent magnet motor viewed from a direction orthogonal to the axial direction, and shows a main magnetic pole part c. The main magnetic pole part c is provided with a first magnet accommodation hole 832c and a second magnet accommodation hole 834c. The first magnet accommodation hole 832c (second magnet accommodation hole 834c) includes an outer wall (outer wall) 832c1 (834c1), an inner wall (inner wall) 832c2 (834c2), and an outer peripheral wall (outer end wall). ) 832c3 (834c3) and a central wall (center side end wall) 832c4 (834c4). Further, an intermediate bridge portion 836c is formed between the first magnet housing hole 832c and the second magnet housing hole 834c, and the first bridge is formed between the first magnet housing hole 832c and the outer peripheral surface 830A of the rotor 830. An outer peripheral bridge portion 837c1 is formed, and a second outer peripheral bridge portion 837c2 is formed between the second magnet housing hole 834c and the outer peripheral surface 830A of the rotor 830. A first permanent magnet having a cross-sectional shape corresponding to the cross-sectional shape of the first magnet accommodation hole 832c (second magnet accommodation hole 834c) is formed in the first magnet accommodation hole 832c (second magnet accommodation hole 834c). 833c (second permanent magnet 835c) is accommodated.
In the conventional permanent magnet motor, the wall 832c1 (834c1) outside the first magnet housing hole 832c (second magnet housing hole 834c) provided in the main magnetic pole part c, as viewed in a cross section orthogonal to the axial direction. The inner wall 832c2 (834c2) and the inner wall 832c2 (834c2) are formed in an arc shape centered on a common center point c811 on the d-axis. That is, the outer walls 832c1 and 834c1 are formed in an arc shape having a radius [R811] centered on the center point c811 on the d-axis, and the inner walls 832c2 and 834c2 are centered on the center point c811 on the d-axis. It is formed in an arc shape with a radius [R812].
When a ferrite magnet having a magnetic flux density lower than that of a rare earth magnet is used for the permanent magnet motor having such a configuration, a first magnet housing hole in which a cross-sectional shape viewed from a direction orthogonal to the axial direction is formed in a rectangular shape, and The lengths of the outer walls 832c1 and 834c1 are longer than when the second magnet accommodation hole is used. Accordingly, the first permanent magnet 833c (second permanent magnet 835c) accommodated in the first magnet accommodation hole 832c (second magnet accommodation hole 834c) in the cross section orthogonal to the axial direction shown in FIG. The length of the outer wall corresponding to the outer wall 832c1 (834c1) of the first magnet housing hole 832c (second magnet housing hole 834c) becomes longer, and the amount of magnetic flux increases. However, when the outer wall 832c1 of the first magnet housing hole 832c and the outer wall 834c1 of the second magnet housing hole 834c are formed in an arc shape centered on a common center point, the outer wall There is a limit to increasing the length of 832c1 and 834c1. For this reason, the efficiency equivalent to the case where a rare earth magnet having a high magnetic flux density is used cannot be obtained.

In the present embodiment, in order to increase the outside length of the first magnet accommodation hole and the second magnet accommodation hole provided in the main magnetic pole portion, the first magnet accommodation hole and the second magnet accommodation hole The outer wall is formed in an arc shape centered on a different center point.
The configuration of the magnet housing hole and the permanent magnet according to the present embodiment will be described with reference to FIG. The first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d provided in the main magnetic pole portions a to d have the same configuration, and the first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d have the same configuration. The first permanent magnets 33a to 33d and the second permanent magnets 35a to 35d accommodated in the magnet accommodation holes 34a to 34d have the same configuration. For this reason, in the following, it accommodates in the 1st magnet accommodation hole 32c and the 2nd magnet accommodation hole 34c which are provided in the main magnetic pole part c, and the 1st magnet accommodation hole 32c and the 2nd magnet accommodation hole 34c, respectively. The first permanent magnet 33c and the second permanent magnet 35c will be described.
When viewed in a cross section orthogonal to the axial direction, the outer wall 32c1 and the inner wall 32c2 of the first magnet housing hole 32c are formed in an arc shape centered on the center point c11. That is, the outer wall 32c1 is formed in a circular arc shape having a radius [R11] centered on the center point c11, which is concave outward, and the inner wall 32c2 is protruding inward (center direction). The center point c11 is formed in an arc shape having a radius [R12]. In addition, the outer wall 34c1 and the inner wall 34c2 of the second magnet housing hole 34c are formed in an arc shape centered on the center point c21. That is, the outer wall 34c1 is formed in a circular arc shape having a radius [R21] centered on the center point c21, which is concave outward, and the inner wall 34c2 is a center point c21 which protrudes inward. Is formed in a circular arc shape having a radius [R22] centered at.
The first permanent magnet 33c (second permanent magnet 35c) housed in the first magnet housing hole 32c (second magnet housing hole 34c) is a first magnet when viewed in a cross section orthogonal to the axial direction. The outer surface of the magnet housing hole 32c (second magnet housing hole 34c) is formed in a shape corresponding to the outer wall 32c1 (34c1) and the inner wall 32c2 (34c2). Inner surface, outer peripheral surface side surface formed in a shape corresponding to the outer peripheral surface side wall 32c3 (34c3), central side surface formed in a shape corresponding to the central side wall 32c4 (34c4) have. That is, the first permanent magnet 33c has an outer surface formed in an arc shape centered on the center point c11 that is concave outward when viewed in the state accommodated in the first magnet accommodation hole 32c. , And has an inner surface formed in an arc shape centering on a central point c11 that protrudes inward. In addition, the second permanent magnet 35c has an outer surface formed in an arc shape centered on a center point c21 that is concave outward when viewed in the state accommodated in the second magnet accommodation hole 34c. The inner surface is formed in a circular arc shape centering on a center point c21 that protrudes inward.

The center points c11 and c12 and the radii [R11], [R12], [R21], and [R22] are the size (diameter or radius) of the rotor 30, the characteristics and thickness of the permanent magnet, the central bridge portion 36c and the second It is set according to the width, desired efficiency, etc. of the first outer peripheral bridge portion 37c1 and the second outer peripheral bridge portion 37c2. In the present embodiment, the radius [R11] and the radius [R21] are set equal, and the radius [R12] and the radius [R22] are set equal. That is, the first magnet housing hole 32c and the second magnet housing hole 34c, and the first permanent magnet 33c and the second permanent magnet 35c are formed in an arc shape (bow shape). In the present specification, the term “arc shape” is used to encompass a substantially arc shape.
In the present embodiment, the intermediate bridge portions 36a to 36d correspond to the “intermediate bridge portion” of the present invention, the first outer peripheral bridge portions 37a1 to 37d1 correspond to the “first outer peripheral bridge portion” of the present invention, The second outer peripheral bridge portions 37a2 to 37d2 correspond to the “second outer peripheral bridge portion” of the present invention, and the center point c11 of the present invention is “the first arc-shaped first wall of the first magnet housing hole”. Corresponding to the “curvature center point”, the center point c21 corresponds to “the second curvature center point of the arc shape of the outer wall of the second magnet housing hole” of the present invention.

  Thus, in the present embodiment, the outer wall and the inner wall of the first magnet housing hole and the outer wall and the inner wall of the second magnet housing hole are viewed in a cross section orthogonal to the axial direction. Are formed in an arc shape centered on different center points. Thus, when viewed in a cross section orthogonal to the axial direction, the outer wall and the inner wall of the first magnet housing hole, the outer wall and the inner wall of the second magnet housing hole are the common center on the d axis. The length of the outer wall of the first magnet housing hole and the outer wall of the second magnet housing hole can be increased as compared with the case where the arc shape is centered on the point. That is, the length of the outer surface corresponding to the outer wall of the first magnet accommodation hole of the first permanent magnet accommodated in the first magnet accommodation hole, the first permanent magnet accommodated in the second magnet accommodation hole. The length of the outer surface corresponding to the outer wall of the second magnet housing hole of the second permanent magnet can be increased. Therefore, the amount of magnetic flux can be increased and the efficiency can be improved.

In the rotor having the above-described configuration, the magnetic flux generated from the first permanent magnets 33a to 33d accommodated in the first magnet accommodation holes 32a to 32d is generated by the intermediate bridge portions 36c to 36d and the first outer peripheral bridge portion 37a1. The magnetic flux generated from the second permanent magnets 35a to 35d that are short-circuited through the second magnet receiving holes 34a to 34d is generated by the intermediate bridge portions 36c to 36d and the second outer peripheral bridge. Short-circuited through the portions 37a2 to 37d2 (short-circuit magnetic flux is generated).
Here, in the conventional permanent magnet electric motor, as shown in FIG. 6, the first magnet housing hole 832 c has the first magnet housing hole 832 c and the outer wall of the first magnet housing hole 832 c and the second magnet housing hole 834 c. The outer surface of the permanent magnet 833c to be accommodated and the second permanent magnet 835c to be accommodated in the second magnet accommodation hole 834c (the surface facing the outer wall of the magnet accommodation hole) is the outer peripheral surface of the rotor 830. It is formed in parallel (including substantially parallel). Further, the magnetic orientation directions of the first permanent magnet 833c and the second permanent magnet 835c are set along a line passing through the common orientation center point c811 on the d axis (referred to as “radial orientation”). ) For this reason, as shown in FIG. 6, a portion on the center side of the outer wall 832c1 of the first magnet housing hole 832c (a portion on the center side of the outer surface of the first permanent magnet 833c magnetized to the N pole) ) Through the intermediate bridge portion 836c, the portion on the center side of the inner wall 832c2 of the first magnet housing hole 832c (the inner surface of the first permanent magnet 833c magnetized to the south pole) And is short-circuited. Or the magnetic flux which generate | occur | produced from the part by the side of the outer peripheral surface of the outer wall 832c1 of the 1st magnet accommodation hole 832c (the part of the outer peripheral surface side of the outer surface magnetized by the N pole of the 1st permanent magnet 833c). The portion on the outer peripheral surface side of the inner wall 832c2 of the first magnet housing hole 832c (the outer periphery of the inner surface magnetized to the south pole of the first permanent magnet 833c) via the first outer peripheral bridge portion 837c1 Flow to the surface side part) and short-circuited. The same applies to the second outer bridge portion 837c2.
Via the intermediate bridge portion 836c, the first outer peripheral bridge portion 837c1, and the second outer peripheral bridge portion 837c2, the inner wall (or the inner wall) When a magnetic flux (short-circuit magnetic flux) flows from the wall to the outer wall, the amount of magnetic flux (effective magnetic flux) flowing between the main magnetic pole portions a to d and the teeth portion 22 of the stator 20 decreases, and the efficiency decreases.

In the present embodiment, in order to decrease the magnetic flux (short-circuit magnetic flux) flowing between the outer wall and the inner wall of the first magnet accommodation hole and the second magnet accommodation hole and increase the effective magnetic flux amount, The magnetic orientation of the end portions of the first permanent magnet and the second permanent magnet is different from the magnetic orientation of the central portion.
The magnetic orientation direction of the permanent magnet of the present embodiment will be described with reference to FIGS. FIG. 3 is a diagram showing the flow of magnetic flux of the present embodiment, FIG. 4 is a diagram for explaining the magnetic orientation directions of the first and second permanent magnets, and FIG. 5 is the intermediate bridge portion. It is a figure explaining the magnetic flux (short-circuit magnetic flux) which flows through.
Since the magnetic orientation directions of the first permanent magnets 33a to 33d and the second permanent magnets 35a to 35d are the same, in the following, the first permanent magnets accommodated in the first magnet accommodation holes 32c of the main magnetic pole portion c. The magnetic orientation direction of the second permanent magnet 35c accommodated in the magnet 33c and the second magnet accommodation hole 34c will be described with reference to FIG. 4 showing a cross-sectional view seen from a direction orthogonal to the axial direction. The first permanent magnet 33c (second permanent magnet 35c) has an outer wall 32c1 (34c1) outside the first magnet accommodation hole 32c (second magnet accommodation hole 34c) when viewed in a cross section orthogonal to the axial direction. Is magnetized so that one of the outer surface opposite to the inner wall 32c2 (34c2) and the inner surface opposite to the inner wall 32c2 (34c2) is the N pole and the other is the S pole (in a direction intersecting the outer surface and the inner surface). The Below, the center part and the edge part of the 1st permanent magnet 33c (2nd permanent magnet 35c) see the cross section orthogonal to an axial direction of the 1st permanent magnet 33c (2nd permanent magnet 35c). Represents the center and end along the outer surface.
The magnetic orientation direction 33A at the center of the first permanent magnet 33c converges on the orientation center point c11 at the center located at a position outside the outer surface of the first permanent magnet 33c. That is, in the central portion of the first permanent magnet 33c, a line indicating the magnetic orientation direction 33A in the central portion (shown by a solid line in FIG. 4) passes through the central orientation center point c11. . Further, the magnetic orientation direction 33C at the end of the first permanent magnet 33c converges to the orientation center point c13 at the end disposed farther from the center orientation center point c11. That is, at the end portion of the first permanent magnet 33c, the line indicating the magnetic orientation direction 33C at the end portion (shown by a two-dot chain line in FIG. 4) passes through the alignment center point c13 at the end portion. ing. And the magnetic orientation direction 33B of the intermediate part between the center part and edge part of the 1st permanent magnet 33c is the intermediate part arrange | positioned between the orientation center point c11 of a center part, and the orientation center point c13 of an edge part. Is converged to the alignment center point c12. That is, in the intermediate portion of the first permanent magnet 33c, the line indicating the magnetic orientation direction 33B in the intermediate portion (shown by a broken line in FIG. 4) passes through the alignment center point c12 in the intermediate portion. .
Similarly, the magnetic orientation direction 35A at the center of the second permanent magnet 35c converges on the orientation center point c21 at the center disposed at a position outside the outer surface of the second permanent magnet 35c. . That is, at the central portion of the second permanent magnet 35c, a line (shown by a solid line in FIG. 4) indicating the magnetic orientation direction 35A at the central portion is set so as to pass through the alignment center point c21 at the central portion. . Further, the magnetic orientation direction 35C at the end of the second permanent magnet 35c converges to the orientation center point c23 at the end disposed farther from the orientation center point c21 at the center. That is, at the end portion of the second permanent magnet 35c, a line indicating the magnetic orientation direction 35C at the end portion (shown by a two-dot chain line in FIG. 4) passes through the end orientation center point c23. ing. And the magnetic orientation direction 35B of the intermediate part between the center part of the 2nd permanent magnet 35c and an edge part is the intermediate part arrange | positioned between the orientation center point c21 of a center part, and the orientation center point c23 of an edge part. Is converged to the alignment center point c22. That is, in the intermediate portion of the second permanent magnet, a line (indicated by a broken line in FIG. 4) indicating the magnetic orientation direction 35B of the intermediate portion is set so as to pass through the alignment center point c22 of the intermediate portion.
The first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) are magnetized so that one side of the magnetic orientation directions 33A to 33C (35A to 35C) is an N pole and the other side is an S pole. .
In the present embodiment, the magnetic orientation direction 33A corresponds to the “magnetic orientation direction of the central portion of the first permanent magnet” of the present invention, and the orientation center point c11 of the central portion corresponds to the “first permanent magnet of the first permanent magnet” of the present invention. The magnetic orientation direction 33C corresponds to the “magnetic orientation direction of the end portion of the first permanent magnet” of the present invention, and the orientation center point c13 of the end portion corresponds to the “first orientation center point” of the present invention. Corresponds to the “orientation center point of the end portion of one permanent magnet”, the magnetic orientation direction 35A corresponds to the “magnetic orientation direction of the center portion of the second permanent magnet” of the present invention, and the orientation center point c21 of the center portion is The magnetic orientation direction 35C corresponds to the “magnetic orientation direction of the end portion of the second permanent magnet” of the present invention, and corresponds to the “alignment center point of the center portion of the second permanent magnet” of the present invention. The orientation center point c23 corresponds to “the orientation center point of the end portion of the second permanent magnet” of the present invention.

Here, the orientation center point c12 (c22) of the intermediate portion of the first permanent magnet 33c (second permanent magnet 35c) and the orientation center point c13 (c23) of the end portion are the first permanent magnet 33c (second As long as it is set far from the orientation center point c11 (c21) at the center of the permanent magnet 35c), as shown in FIG. 5, the outer side of the first permanent magnet 33c (second permanent magnet 35c) On a line c1 (c2) (indicated by a one-dot chain line in FIGS. 4 and 5) connecting the center point (circumferential center point) c32 (c34) of the surface of the surface and the alignment center point c11 (c21) of the central portion. It is preferable to set (including a mode of setting on the approximate line c1).
Further, the magnetic orientation direction 33C (35C) at the end of the first permanent magnet 33c (second permanent magnet 35c) converges to the orientation center point c13 (c23) at the end located at infinity. May be. That is, in the present embodiment, “the orientation center point of the end portion of the first permanent magnet (second permanent magnet)” includes the orientation center point disposed at infinity. In this case, for example, the magnetic orientation direction 33C (35C) at the end of the first permanent magnet 33c (second permanent magnet 35c) is the outer surface of the first permanent magnet 33c (second permanent magnet 35c). Is parallel (including substantially parallel) to a line c1 (c2) connecting the center point (circumferential center point) c32 (c34) and the center of alignment center c11 (c21).
In addition, the magnetic orientation direction 33B (35B) of the intermediate part of the 1st permanent magnet 33c (2nd permanent magnet 35c) is the orientation center point of the center part of the 1st permanent magnet 33c (2nd permanent magnet 35c). An intermediate orientation center point c12 arranged continuously or stepwise between c11 (c21) and an orientation center point c13 (c23) at the end of the first permanent magnet 33c (second permanent magnet core 35c). You may be comprised so that it may converge to (c22). That is, the orientation direction 33C (35C) of the end portion of the first permanent magnet 33c (second permanent magnet 35c) from the orientation direction 33A (35A) of the center portion of the first permanent magnet 33c (second permanent magnet 35c). ) May change continuously or stepwise. Further, the magnetic orientation direction of the first permanent magnet 33c (second permanent magnet 35c) may be only the magnetic orientation direction 33A (35A) at the center and the magnetic orientation 33C (35C) at the end (intermediate). The magnetic orientation direction of the part may be omitted).
In FIG. 4, the center of orientation of the central portion of the first permanent magnet 33c (second permanent magnet 35c) is set to the outer wall 32c1 of the first magnet housing hole 32c (second magnet housing hole 34c). Although it is arranged at the arc-shaped center point c11 (c21) of (34c1), the orientation center point of the central portion of the first permanent magnet 33c (second permanent magnet 35c) can be arranged at an appropriate position.

As described above, in the present embodiment, the first permanent magnets 33a to 33d (the second permanent magnets accommodated in the second magnet accommodation holes 34a to 34d) accommodated in the first magnet accommodation holes 32a to 32d. The magnetic orientation direction 33A (35A) in the central portion of the magnets 35a to 35d is converged to the orientation central point c11 (c21) in the central portion. As a result, the gap magnetic flux density distribution can be made close to a sine wave shape, and the occurrence of vibration and sound due to cogging torque can be suppressed.
Further, end portions of the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d accommodated in the second magnet accommodation holes 34a to 34d) accommodated in the first magnet accommodation holes 32a to 32d, respectively. The magnetic orientation direction 33C (35C) converges to the orientation center point c13 (c23) at the end located farther (including infinity) than the orientation center point c11 (c21) at the center. As a result, as shown in FIG. 5, the center-side wall 32c4 of the first magnet housing hole 32c (the surface on the center side magnetized to the north pole of the first permanent magnet 33c) via the intermediate bridge portion 36c. ) And the inner wall 32c2 of the first magnet housing hole 32c (the inner surface magnetized by the south pole of the first permanent magnet 33c) flows, but the first magnet The outer wall 32c1 of the housing hole 32c (the outer surface magnetized by the N pole of the first permanent magnet 33c) and the inner wall 32c2 of the first magnet housing hole 32c (the S pole of the first permanent magnet 33c) Magnetic flux (short-circuit magnetic flux) is less likely to flow between the inner surface and the inner surface. Further, the central side wall 34c4 (the surface on the central side magnetized to the north pole of the second permanent magnet 35c) of the second magnet accommodation hole 34c and the second magnet accommodation hole via the intermediate bridge portion 36c. Magnetic flux (short-circuit magnetic flux) flows between the inner wall 34c2 of 34c (the inner surface magnetized by the south pole of the second permanent magnet 35c), but the outer wall 34c1 of the second magnet housing hole 34c. (The outer surface magnetized to the north pole of the second permanent magnet 35c) and the inner wall 34c2 of the second magnet housing hole 34c (the inner surface magnetized to the south pole of the second permanent magnet 35c) ), It is difficult for magnetic flux (short-circuit magnetic flux) to flow. Similarly, as shown in FIG. 3, the outer walls of the first and second magnet housing holes 32a to 32d and 34a to 34d are interposed via the first and second outer peripheral bridge portions 37a1 to 37d1 and 37a2 to 37d2. 32a1 to 32d1 and 34a1 to 34d1 (the outer surfaces of the first and second permanent magnets 33a to 33d and 35a to 35d) and the inner wall 32a2 of the first and second magnet housing holes 32a to 32d and 34a to 34d The magnetic flux (short-circuit magnetic flux) hardly flows between ˜32d2 and 34a2 to 34d2 (the inner surfaces of the first and second permanent magnets 33a to 33d and 35a to 35d).
Therefore, a decrease in the amount of magnetic flux (effective magnetic flux) flowing between the main magnetic pole portions a to d and the teeth portion 22 of the stator 20 can be prevented, and the efficiency can be improved.

In the first embodiment, each of the main magnetic pole portions a to d has a one-layer structure permanent in which only one set of first and second magnet accommodation holes (a set of first and second permanent magnets) is provided. Although the magnet motor has been described, the present invention can also be configured as a multi-layered permanent magnet motor. A second embodiment configured as a permanent magnet motor having a multilayer structure will be described below.
The permanent magnet motor of the second embodiment is configured by the stator 20 of the first embodiment shown in FIG. 1 and the rotor 130 shown in FIG. This embodiment is configured as a permanent magnet motor having a two-layer structure.
In the present embodiment, as in the first embodiment, the outer circumferential surface of the rotor 130 (rotor core 131) is an arc having a radius [Rd] centered on the center point O of the rotor on the d axis. Arcs having a radius [Rq] centered on center points (Pbc, Pcd) separated in the opposite direction from the center point O of the rotor 130 on the q axis, and the first curved portions 130a to 130d formed in the shape The second curved portions 130ab to 130da formed in a shape are alternately connected.
In the rotor 130 (rotor core 131), a first layer first magnet housing hole 142a to 142d and a first layer magnet housing hole are formed in each main magnetic pole portion a to d. A set of second magnet housing holes 144a to 144d is provided. Also, the second layer first magnet housing holes 146a to 146d and the second layer second magnet constituting the second layer magnet housing hole inside (center side) from the first layer magnet housing hole. Accommodating holes 148a to 148d are provided. The first permanent magnets 143a to 143d, 145a to 145d, 147a to 147d, and 149a to 149d are accommodated in the magnet accommodation holes, respectively. Intermediate bridge portions 136a1 to 136d1 of the first layer are formed between the first magnet housing holes 142a to 142d of the first layer and the second magnet housing holes 144a to 144d of the first layer. The first outer peripheral bridge portions 137a1 to 137d1 are formed between the first magnet housing holes 142a to 142d and the outer peripheral surface of the rotor 130, and the first layer second magnet housing holes 144a to 144d and Between the outer peripheral surface of the rotor 130, second outer peripheral bridge portions 137a2 to 137d2 of the first layer are formed. Between the second layer first magnet housing holes 146a to 146d and the second layer second magnet housing holes 148a to 148d, second layer intermediate bridge portions 136a2 to 136d2 are formed, and the second layer first magnet housing holes 146a to 146d are formed. The first outer peripheral bridge portions 137a3 to 137d3 of the second layer are formed between the first magnet accommodating holes 146a to 146d and the outer peripheral surface of the rotor 130, and the second layer second magnet accommodating holes 148a to 148d Between the outer peripheral surface of the rotor 130, second outer peripheral bridge portions 137a4 to 137d4 of the second layer are formed.
Each magnet accommodation hole is formed by the outer wall, the inner wall, the outer peripheral surface side wall, and the center side wall, as in the first embodiment. In addition, each permanent magnet includes an outer wall, an inner wall, an outer peripheral surface side wall, an outer surface formed in a shape corresponding to the central wall, an inner surface, and an outer peripheral surface surface. And has a central surface.

In the present embodiment, the outer wall and the inner wall of the first magnet accommodation hole of each layer are formed in an arc shape centering on the first center point, and the second magnet accommodation hole of each layer is It is formed in an arc shape centering on a second center point different from the center point of one. That is, as shown in FIG. 7, the outer and inner walls of the first magnet housing hole 142c of the first layer and the first magnet of the second layer provided in the main magnetic pole portion c. The outer wall and the inner wall of the accommodation hole 146c are each formed in an arc shape having radii [R111], [R112], [R113], and [R114] around the center point c111. Further, the outer wall and the inner wall of the second magnet housing hole 144c of the first layer and the outer wall and the inner wall of the second magnet housing hole 148c of the second layer provided in the main magnetic pole part c. Each of the walls is formed in an arc shape having radii [R121], [R122], [R123], and [R124] around the center point c121.
The magnetic orientation direction of each permanent magnet can also be set as in the first embodiment. Moreover, it can also comprise in the multilayered structure of three or more layers.

In this embodiment, since it has a multilayer structure, the reluctance torque due to the rotor core between layers can be used, and the efficiency can be improved. Further, by adopting a multilayer structure, the amount of magnetic flux flowing through the teeth portion when the switching portion (connection point portion) of the main magnetic pole portions a to d and the auxiliary magnetic pole portions ab to da passes through the teeth portion of the stator. A sudden change can be prevented.
Further, similarly to the first embodiment, the magnet housing holes provided on the outer peripheral side (in FIG. 7, the first magnet housing holes 142a to 142d of the first layer constituting the first layer and the first Since the length of the outer wall of the one-layer second magnet housing holes 144a to 144d) can be increased, the amount of magnetic flux can be increased.
Further, when the magnetic orientation direction of the permanent magnet is set as in the first embodiment, the short-circuit magnetic flux through the intermediate bridge portion, the first outer peripheral bridge portion, and the second outer peripheral bridge portion can be reduced. And the amount of effective magnetic flux can be increased.
Further, by configuring the outer peripheral surface by connecting the first curved portion and the second curved portion having different radii of curvature, the same effects as those of the first embodiment are obtained.
Therefore, by using this embodiment, as in the first embodiment, even when a ferrite magnet or the like having a lower magnetic flux density than a rare earth magnet is used, the permanent magnet has the same efficiency as that using a rare earth magnet. A magnet motor can be obtained.

The method of configuring the outer peripheral surface of the rotor by the first curved portion and the second curved portion having different curvature radii is not limited to the methods of the first and second embodiments. The third embodiment of the present invention will be described below.
The third embodiment includes the stator 20 of the first embodiment shown in FIG. 1 and the rotor 230 shown in FIG. The rotor 230 is the same as that of the first embodiment except that the method of configuring the outer peripheral surface is different from that of the rotor 30 of the first embodiment.
In the present embodiment, the first curved portions 230a to 230d corresponding to the main magnetic pole portions a to d of the rotor 230 have a radius [R1] centered on the center point O of the rotor 230 (rotor core 231). The second curve portions 230ab to 230da corresponding to the auxiliary magnetic pole portions ab to da have a radius [R2 (<R1) centered on the center point O of the rotor 230 (rotor core 231). ] Arc shape.

When the magnetic flux generated from the permanent magnet accommodated in the magnet accommodation hole is short-circuited through the teeth portion of the stator, the magnetic flux flowing through the teeth portion fluctuates and cogging torque is generated. When cogging torque is generated, sound and vibration are generated. Below, 4th implementation which prevents that the magnetic flux which generate | occur | produces from a permanent magnet is short-circuited via the teeth part of a stator is demonstrated.
The fourth embodiment includes the stator 20 of the first embodiment shown in FIG. 1 and the rotor 330 shown in FIG. The rotor 330 has the same configuration as the rotor 30 of the first embodiment except that notches are formed in the first and second outer peripheral bridge portions.
In the present embodiment, the outer peripheral surface of the rotor 330 is formed by first curved portions 330a to 330d corresponding to the main magnetic pole portions a to d and second curved portions 330ab to 330da corresponding to the auxiliary magnetic pole portions ab to da. It is configured.
The rotor 330 is provided with first magnet housing holes 332a to 332d and second magnet housing holes 334a to 334d. Intermediate bridge portions 336a to 336d are formed between the first magnet housing holes 332a to 332d and the second magnet housing holes 334a to 334d, and the first magnet housing holes 332a to 332d and the rotor 330 (rotor core) are formed. 331) are formed with first outer peripheral bridge portions 337a1 to 337d1 between the outer peripheral surfaces (second curved portions 330ab to 330da in FIG. 9), and the second magnet housing holes 334a to 334d and the rotor 330 ( Second outer peripheral bridge portions 337a2 to 337d2 are formed between the rotor core 331) and the rotor core 331).
Further, in the present embodiment, the first outer peripheral bridge portions 337a1 to 337d1 (second outer peripheral bridge portions 337a2 to 337d2) have first magnet receiving holes 332a to 332d (second magnet receiving holes 334a to 334d). ) Are notched portions 331a1 to 331d1 (331a2 to 331d2) at locations facing the outer peripheral surface side wall. The notches 331a1 to 331d1 and 331a2 to 331d2 are formed in a concave shape in the outward direction by notching from the line along the second curved line portions 330ab to 330da to the center side.
The circumferential lengths of the notches 331a1 to 331d1 and 331a2 to 331d2 are set to be equal to or larger than the width of the base portion 22a of the teeth portion 22 of the stator, and preferably longer than the circumferential length of the teeth tip surface 22d of the teeth portion 22. It is preferable.

In the fourth embodiment. Although notches are formed in the first and second outer bridge portions, holes can also be formed. FIG. 10 shows a fifth embodiment in which holes are formed in the first and second outer peripheral bridge portions.
The fifth embodiment includes the stator 20 of the first embodiment shown in FIG. 1 and the rotor 430 shown in FIG. The rotor 430 has the same configuration as the rotor 30 of the first embodiment, except that holes are formed in the first and second outer peripheral bridge portions.
In the present embodiment, the first outer peripheral bridge portions 437a1 to 437d1 (second outer peripheral bridge portions 437a2 to 437d2) have first magnet receiving holes 432a to 432d (second magnet receiving holes 434a to 434d). Holes 431a1 to 431d1 (431a2 to 431d2) are formed at locations facing the outer peripheral surface side wall. The holes 431a1 to 431d1 and 431a2 to 431d2 may be configured as voids or may be configured by filling a nonmagnetic material.
The circumferential lengths of the holes 431a1 to 431d1 and 431a2 to 431d2 are set to be not less than the width of the base portion 22a of the teeth portion 22 of the stator, preferably not less than the circumferential length of the tooth tip surface 22d of the teeth portion 22. Is preferred.

In the fourth and fifth embodiments, the magnetic flux generated from the first and second permanent magnets housed in the first and second magnet housing holes is passed through the teeth portion of the stator. A short circuit can be prevented. Thereby, the amount of effective magnetic flux can be increased and efficiency can be improved.
In addition, the torque pulsation is reduced by reducing the fluctuation of the reluctance torque, or the magnetic attraction force in the radial direction between the rotor and the stator is reduced by reducing the magnetic flux short circuit amount at the end of the permanent magnet. Noise and vibration can be reduced.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions are possible.
The magnet housing hole and the permanent magnet housed in the magnet housing hole include a magnet housing hole in which at least the outer wall is formed in an arc shape and an outer surface formed in a shape corresponding to the outer wall of the magnet housing hole. Any permanent magnet may be used.
In addition, the configuration in which the magnetic orientation at the end of the permanent magnet is set so as to be along a line passing through the orientation center at the end far from the center at the center can be omitted.
Moreover, the structure which forms a notch part and a hole in the location which opposes the wall by the side of the outer peripheral surface of a magnet accommodation hole in an outer periphery bridge part can also be abbreviate | omitted.
Each configuration described in the embodiment can be used alone, or a plurality selected as appropriate can be used in combination.
The present invention is not limited to a permanent magnet motor, and can be configured as a permanent magnet rotating machine having various configurations.

DESCRIPTION OF SYMBOLS 10 Permanent magnet motor 20 Stator 21 Yoke part 22 Teeth part 23 Slot 30, 130, 230, 330, 430, 830 Rotor 30a-30d, 130a-130d, 230a-230d, 330a-330d, 430a-430d 1st Curved portions 30ab-30da, 130ab-130da, 230ab-230da, 330ab-330da, 430ab-430da Second curved portions 31, 131, 231, 431 Rotor cores 32a-32d, 34a-34d, 142a-142d, 144a- 144d, 146a-146d, 148a-148d, 232a-232d, 234a-234d, 332a-332d, 334a-334d, 432a-432d, 434a-434d, 832c, 834c Magnet receiving holes 32a1- 32d1, 142a1, 144a1, 146a1, 148a1, 832c1, 834c1 Outer walls 32a2 to 32d2, 142a2, 144a2, 146a2, 148a2, 832c2, 834c2 Inner walls 32a3 to 32d3, 142a3, 144a3, 146a3, 148a3, 832c3 Surface side walls 32a4 to 32d4, 142a4, 144a4, 146a4, 148a4, 832c4, 834c4 Central side walls 33a to 33d, 35a to 35d, 143a to 143d, 145a to 145d, 147a to 147d, 149a to 149d, 233a to 233d 235a-235d, 333a-333d, 335a-335d, 433a-433d, 435a-435d, 833c, 835c permanent magnets 36a-36d, 36a1-136d1, 136a2-136d2, 236a-236d, 336a-336d, 436a-436d, 836c Intermediate bridge portions 37a1-37d1, 37a2-37d2, 137a1-137d1, 137a2-137d2, 137a3-137d3, 137a4-137d4, 237a1- 237d1, 237a2 to 237d2, 337a1 to 337d1, 337a2 to 337d2, 437a1 to 437d1, 437a2 to 437d2, 837c1, 837c2 outer peripheral bridge portions 38a to 38d, 138a to 138d, 238a to 238d, 338a to 338d, 438a to 438d caulking pin insertion holes 40, 140, 240, 340, 440 Rotating shaft insertion holes 331a1-331d1, 331a2-331d2 Notch 431a ~431d1,431a2~431d2 hole 830A peripheral surface

  The present invention relates to a permanent magnet rotating machine in which a permanent magnet is housed in a magnet housing hole provided in a rotor, and more particularly to a technique for improving the efficiency of the permanent magnet rotating machine.

  As an electric motor for driving a compressor such as an air conditioner (air conditioner) or a refrigerator, an electric motor for driving a vehicle, an in-vehicle device, or the like, a permanent magnet electric motor (“permanent”) in which a permanent magnet is accommodated in a magnet accommodating hole provided in a rotor. It is called a “magnet embedded motor”. This type of permanent magnet motor includes, for example, a stator provided with a tooth portion, and a rotor that is rotatably arranged through a gap between a tooth tip surface of the tooth portion and a tooth. In the rotor, when viewed in a cross section orthogonal to the axial direction of the rotor, main magnetic pole portions and auxiliary magnetic pole portions are alternately arranged in the circumferential direction. The main magnetic pole portion is provided with a magnet accommodation hole, and a permanent magnet is accommodated in the magnet accommodation hole. This permanent magnet motor can utilize both the magnet torque due to the magnetic flux of the permanent magnet accommodated in the magnet accommodation hole of the main magnetic pole part and the reluctance torque due to the saliency of the auxiliary magnetic pole part. In Patent Document 1, a first magnet accommodation hole and a second magnet accommodation hole are arranged on the main magnetic pole portion of a rotor with an intermediate bridge portion interposed therebetween, and the first magnet accommodation hole and the second magnet are arranged. A permanent magnet motor is described in which the housing hole is formed in an arc shape centering on a common center point on the d-axis line of the main magnetic pole portion.

JP 11-285186 A

Conventionally, in a permanent magnet motor, a rare earth magnet having a high magnetic flux density has been used. In particular, neodymium magnets containing Nd (neodymium), Fe (iron), Co (cobalt), B (boron), etc. as constituent components are used. However, since rare earth magnets such as neodymium magnets are expensive, permanent magnet motors using inexpensive permanent magnets, for example, permanent magnet motors using ferrite magnets, etc., whose magnetic flux density is lower than rare earth magnets but are cheaper Development is desired.
In the permanent magnet motor in which the permanent magnet is accommodated in the magnet accommodation hole provided in the main magnetic pole portion of the rotor, the amount of magnetic flux is the outer wall of the magnet accommodation hole (the wall on the side facing the teeth portion of the stator) ) Is determined by the length. For this reason, in order to obtain a permanent magnet motor having the same efficiency as the case where a rare earth magnet having a high magnetic flux density is used using a magnet having a low magnetic flux density such as a ferrite magnet, the length of the outer wall is long. It is necessary to use a rotor provided with a magnet housing hole.
Therefore, the length of the outer wall of the magnet accommodation hole is longer than that of a rotor in which the first magnet accommodation hole and the second magnet accommodation hole formed in a linear shape are arranged in a V shape with the intermediate bridge portion interposed therebetween. It is conceivable to use the rotor described in Patent Document 1. However, even if a permanent magnet electric motor is configured by accommodating a permanent magnet having a low magnetic flux density such as a ferrite magnet in the magnet housing hole of the rotor described in Patent Document 1, a permanent magnet configured using a rare earth magnet having a high magnetic flux density is used. The same efficiency as a magnet motor cannot be obtained. In general, a rare earth magnet having a rectangular cross section is used in terms of manufacturing cost.
The present invention was devised in view of such points, and by increasing the length of the outer wall of the magnet housing hole provided in the main magnetic pole portion, the efficiency of the permanent magnet rotating machine is improved. An object of the present invention is to obtain a permanent magnet rotating machine having the same efficiency as the case of using a rare earth magnet even when a ferrite magnet having a magnetic flux density lower than that of a rare earth magnet is used.

The first invention of the present invention is:
The rotor includes a stator and a rotor, and the rotor is alternately arranged with a main magnetic pole portion and an auxiliary magnetic pole portion in a circumferential direction when viewed in a cross section orthogonal to the axial direction. A permanent magnet rotating machine in which a permanent magnet is arranged,
The outer peripheral surface of the rotor is composed of a first curved portion and a second curved portion when viewed in a cross section orthogonal to the axial direction, and the first curved portion intersects the d-axis line of the main magnetic pole portion. The second curved portion intersects with the q-axis line of the auxiliary magnetic pole portion, the convex portion faces the outward direction, and the curvature is curved. A radius is formed in a second curved shape different from the curvature radius of the first curvature shape;
The main magnetic pole portion has an outer surface that is concave outward, an inner surface that protrudes inward, an outer peripheral surface, and a central surface when viewed in a cross section orthogonal to the axial direction. In the first permanent magnet and the second permanent magnet, an intermediate bridge portion is formed between a center-side surface of the first permanent magnet and a center-side surface of the second permanent magnet, and the first permanent magnet A first outer bridge portion is formed between the outer peripheral surface of the permanent magnet and the outer peripheral surface of the rotor, and between the outer peripheral surface of the second permanent magnet and the outer peripheral surface of the rotor. Arranged so as to form a second outer peripheral bridge portion, an outer surface and an inner surface of the first permanent magnet are formed in an arc shape centered on a first curvature center point, and the second The outer surface and the inner surface of the permanent magnet are centered on a second curvature center point different from the first curvature center point, Serial is formed radially equal radius of the arc shape of the outer surface and inner surface of the first permanent magnet,
The position of the first curvature center point and the second curvature center point is such that the length of the outer surface of the first permanent magnet and the outer surface of the second permanent magnet is the same diameter. When the outer surface of the first permanent magnet and the outer surface of the second permanent magnet are formed in an arc shape centered on the common center of curvature on the d-axis, using permanent magnets of the same thickness The permanent magnet rotating machine is set to be longer than the maximum length of the outer surface of the first permanent magnet and the outer surface of the second permanent magnet.
The permanent magnet rotating machine of the present invention is typically configured as a permanent magnet embedded electric motor.
“Outward direction” represents a direction away from the center point of the rotor (a direction facing the stator) when viewed in a cross section orthogonal to the axial direction of the rotor. “D-axis” represents a line connecting the center point of the rotor and the center point in the circumferential direction of the main magnetic pole portion when viewed in a cross section orthogonal to the axial direction of the rotor, and “q-axis” represents the rotor A line connecting the center point of the rotor and the center point in the circumferential direction of the auxiliary magnetic pole portion is shown in a cross section orthogonal to the axial direction.
The “outer surface” and “inner surface” are the ones on both sides along the longitudinal direction that are closer to the surface farther from the center of the rotor, as viewed in the cross section perpendicular to the axial direction of the rotor. Represents the surface. The “center side surface” represents a surface disposed at a position facing other permanent magnets provided in the main magnetic pole portion, and the “outer surface side surface” faces the outer peripheral surface of the rotor. The surface arranged at the position is shown.
The configuration “formed in an arc shape” includes a mode in which the arc shape is formed.
A first curvature center point and a second curvature center point different from each other in the arc shape of the outer surface and the inner surface of the first permanent magnet and the arc shape of the outer surface and the inner surface of the second permanent magnet, respectively. Are formed in a circular arc shape with the center at the center, and by setting the first curvature center point and the second curvature center point, the outer surface and the inner surface of the first permanent magnet and the second permanent magnet The length of the outer surface and the inner surface can be increased. Thereby, the amount of magnetic flux can be increased and the efficiency can be improved. Further, the amount of magnetic flux from the first permanent magnet and the amount of magnetic flux from the second permanent magnet become substantially equal, and pulsation of the amount of magnetic flux can be prevented. Further, the thickness of the permanent magnet can be made constant, and variations in demagnetization characteristics can be prevented. In addition, the reluctance torque by the rotor core between the inner surface of the first permanent magnet and the rotation shaft insertion hole and between the inner surface of the second permanent magnet and the rotation shaft insertion hole becomes uniform, and the cogging torque is reduced. Can be reduced. Thereby, generation | occurrence | production of the sound and vibration by a cogging torque can be reduced.
In the present invention, the outer peripheral surface of the rotor is formed by the first curved portion and the second curved portion having different radii of curvature, and the outer sides of the first permanent magnet and the second permanent magnet provided in the main magnetic pole portion. Efficiency is improved by using the structure which lengthens the length of this surface. Thereby, for example, even when a ferrite magnet having a magnetic flux density lower than that of the rare earth magnet is used, the same efficiency as that when the rare earth magnet is used can be obtained.

In the second invention of the present invention, a set of the first permanent magnet and the second permanent magnet is provided in multiple layers in the radial direction of the rotor, and the outer surface and the inner surface of the first permanent magnet of each layer are The outer surface and the inner surface of the second permanent magnet of each layer are formed in an arc shape centered on the second curvature center point. Yes.
By adopting a multilayer structure, the reluctance torque due to the rotor core between the layers can be used, so that the efficiency can be further improved.

By using the first invention and the second invention , the amount of magnetic flux can be increased to improve the efficiency. Thereby, even when a ferrite magnet having a magnetic flux density lower than that of the rare earth magnet is used, a permanent magnet rotating machine having the same efficiency as that when the rare earth magnet is used can be obtained.

It is sectional drawing which looked at 1st Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 1st Embodiment from the direction orthogonal to an axial direction. It is the elements on larger scale of FIG. It is a figure explaining the magnetic orientation direction of the permanent magnet of 1st Embodiment. It is a figure explaining the effect | action of 1st Embodiment. It is a figure explaining the effect | action of a prior art. It is sectional drawing which looked at the rotor of 2nd Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 3rd Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 4th Embodiment from the direction orthogonal to an axial direction. It is sectional drawing which looked at the rotor of 5th Embodiment from the direction orthogonal to an axial direction.

Embodiments of the present invention will be described below with reference to the drawings.
A first embodiment of the present invention is shown in FIGS. In the first embodiment, the present invention is referred to as a permanent magnet motor in which a permanent magnet is accommodated in a magnet accommodation hole provided in a main magnetic pole portion of a rotor ("embedded permanent magnet motor"). ). 1 is a cross-sectional view of the permanent magnet motor 10 according to the first embodiment viewed from a direction orthogonal to the axial direction, and FIG. 2 is a cross-section of the rotor 30 viewed from a direction orthogonal to the axial direction. FIG. In addition, the rotor 30 has shown the case where the number of magnetic poles is 4 (the number of pole pairs is 2).
The permanent magnet motor 10 according to the present embodiment includes a stator 20 and a rotor 30.
The stator 20 is constituted by, for example, a stator core formed by stacking electromagnetic steel plates. The stator 20 has a yoke portion 21 and a teeth portion 22. A slot 23 is formed by the tooth portion 22, and a stator winding is accommodated in the slot 23 by a distributed winding method or a concentrated winding method. As shown in FIG. 3, the tooth portion 22 includes a base portion 22a and tooth end portions 22b and 22c provided on both sides of the base portion 22a in the rotational direction. A tooth tip surface 22d is formed by the surface of the base portion 22a and the teeth end portions 22b and 22c on the side facing the rotor 30. The rotor 30 is rotatably arranged in a state where a gap (gap) between the outer peripheral surface of the rotor 30 and the tooth tip surface 22d of the teeth portion 22 of the stator 20 is set to g.

The rotor 30 is constituted by a rotor core 31 formed by laminating electromagnetic steel plates, for example. The rotor core 31 is formed with a rotation shaft insertion hole 40 into which a rotation shaft is inserted, and main magnetic pole portions a, b, c, d and auxiliary magnetic pole portions ab, bc, cd, da are arranged in the circumferential direction. Alternatingly arranged. The rotating shaft is inserted into the rotating shaft insertion hole 40 by, for example, a press-fitting method or a shrinking method.
The rotor core 31 is formed with caulking pin insertion holes 38a to 38d into which caulking pins for fixing the laminated electromagnetic steel plates are inserted. As the caulking pin, it is preferable to use a caulking pin formed of a magnetic material.

The outer peripheral surface of the rotor core 31 (hereinafter referred to as “rotor 30”) is supplemented with first curved portions (first outer peripheral portions) 30a, 30b, 30c, 30d corresponding to the main magnetic pole portions a to d. The second curved portions (second outer peripheral portions) 30ab, 30bc, 30cd, and 30da corresponding to the magnetic pole portions ab to da are alternately arranged.
The first curved portions 30a to 30d intersect a line (hereinafter referred to as “d-axis”) connecting the center point O of the rotor 30 and the center point in the circumferential direction of the main magnetic pole portions a to d, and the protrusions are outward. It is formed in the 1st curve shape which is suitable for. The second curved portions 30ab to 30da intersect a line (hereinafter referred to as “q-axis”) connecting the center point O of the rotor 30 and the center point in the circumferential direction of the auxiliary magnetic pole portions ab to da, and the protrusions are It is formed in a second curved shape that faces outward. The curvature radius [Rq] of the second curve shape of the second curve portions 30ab to 30da is set larger than the curvature radius [Rd] of the first curve shape of the first curve portions 30a to 30d. (Rq> Rd). The first curve portions 30a to 30d and the second curve portions 30ab to 30da are connected at connection points 30a1 to 30d1 and 30a2 to 30d2. The description “outward direction” represents a direction away from the center point of the rotor.
In the present embodiment, the first curved portions 30 a to 30 d are formed in an arc shape having a radius [Rd] with the center point O of the rotor 30 as the center. The second curved line portions 30ab to 30da are arcs having a radius [Rq] centered on a point on the q axis that is away from the center point O of the rotor 30 in the opposite direction to the second curved line portions 30ab to 30da. It is formed into a shape. FIG. 1 shows the center point (curvature center point) Pab of the arc shape of the second curve portion 30ab, and FIG. 2 shows the center point (curvature center point) Pbc of the arc shape of the second curve portion 30bc. The arc-shaped center point (curvature center point) Pcd of the second curved portion 30cd is shown.
The opening angle θ of the first curved portions 30a to 30d is set in a range where high efficiency can be obtained.
The curved shapes of the first curved portions 30a to 30d and the second curved portions 30ab to 30da may be a projecting shape such as an arc shape or an elliptical shape. Further, the positions of the center points (curvature center points) of the first curved portions 30a to 30d and the center points (curvature center points) of the second curved portions 30ab to 30da can be changed as appropriate. For example, the center point of the first curve portions 30a to 30d may be set to a point on the d-axis line that is away from the center point O of the rotor 30 in the direction of the first curve portions 30a to 30d.
In the present embodiment, the first curve portions 30a to 30d correspond to the “first curve portion” of the present invention, and the center point O of the rotor 30 corresponds to the “first curve-shaped first of the present invention”. [Rd] corresponds to the “curvature radius of the first curved shape” of the present invention. The second curve portions 30ab-30da correspond to the “second curve portion” of the present invention, and the points Pab, Pbc, Pcd correspond to the “second curvature center point of the second curve shape” of the present invention. Correspondingly, [Rq] corresponds to the “curvature radius of the second curved shape” of the present invention.

  When the first curve portions 30 a to 30 d and the second curve portions 30 ab to 30 da are switched (portions 30 a 1 to 30 d 1 and 30 a 2 to 30 d 2) pass through a portion facing the teeth portion 22, the teeth portion 22. The amount of magnetic flux flowing through the coil can be prevented from changing suddenly, and an increase in harmonic components contained in the electromotive force waveform of the electromotive force induced in the stator winding can be prevented. Thus, for example, without using a rotor position detection sensor, a permanent magnet motor can be used using a sensorless control device that detects a rotor position based on an electromotive force waveform of an electromotive force induced in a stator winding. In the case of control, it is possible to prevent a decrease in rotor position detection accuracy due to harmonic components included in the electromotive force waveform. Therefore, it is possible to prevent a decrease in efficiency due to a decrease in rotor position detection accuracy. Further, since a sufficient electromotive force can be induced in the stator winding, it is not necessary to increase the number of turns of the stator winding. Thereby, the fall of the efficiency by the copper loss of a stator winding | coil can be prevented.

The main magnetic pole portions a to d are provided with first magnet housing holes 32a to 32d and second magnet housing holes 34a to 34d. First permanent magnets 33a to 33d are accommodated in the first magnet accommodation holes 32a to 32d, and second permanent magnets 35a to 35d are accommodated in the second magnet accommodation holes 34a to 34d. The first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) are accommodated in the first magnet accommodation holes 32a to 32d (second magnet accommodation holes 34a to 34d) by, for example, a gap fitting method. The The first permanent magnets 33a to 33d and the second permanent magnets 35a to 35d are magnetized so that the polarities of the main magnetic pole portions a to d adjacent in the circumferential direction are opposite to each other. In FIG. 2, the first permanent magnet 33 a and the second permanent magnet 35 a of the main magnetic pole part a, and the first permanent magnet 33 c and the second permanent magnet 35 c of the main magnetic pole part c are N poles on the outer peripheral surface side, and the center A main magnetic pole part b, which is magnetized so that the side becomes an S pole, and is adjacent to the main magnetic poles a and c, a first permanent magnet 33b and a second permanent magnet 35b. The first permanent magnet 33d and the second permanent magnet 35d of the main magnetic pole portion d are magnetized so that the outer peripheral surface side is the S pole and the center side is the N pole.
In the present embodiment, the first magnet housing holes 32a to 32d include outer walls (outer walls) 32a1 to 32d1, inner walls (inner walls) 32a2 to 32d3, outer peripheral surface walls (outer peripheral end walls) 32a3. 32d3 and the center side wall (center side end wall) 32a4 to 32d4. Similarly, the second magnet housing holes 34a to 34d are formed on the outer walls (outer walls) 34a1 to 34d1, the inner walls (inner walls) 34a2 to 34d2, the outer peripheral side walls (outer end walls) 34a3 to 34d3, the center. Side walls (center side end walls) 34a4 to 34d4 are formed. The “outer wall” and “inner wall” are the center points of the rotor 30 (rotor core 31) among the walls on both sides along the longitudinal direction when the rotor 30 is viewed in a cross section perpendicular to the axial direction. The far wall from O and the near wall are shown. Further, the “outer peripheral wall” and “center wall” are walls arranged at positions facing the outer peripheral surface of the rotor 30 and other magnet housing holes provided in the main magnetic pole portions a to d. The wall arrange | positioned in the position which opposes is represented. The shape of the cross section orthogonal to the axial direction of the first permanent magnets 33a to 33d is orthogonal to the axial direction of the first magnet housing holes 32a to 32d to the extent that it can be accommodated in the first magnet housing holes 32a to 32d. It is formed in a shape corresponding to the shape of the cross section. Similarly, the shape of the cross section orthogonal to the axial direction of the second permanent magnets 35a to 35d is such that the second magnet accommodating holes 34a to 34d can be accommodated in the second magnet accommodating holes 34a to 34d. It is formed in a shape corresponding to the shape of the cross section orthogonal to. Typically, the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) are first magnet accommodation holes 32a to 32d (second magnet accommodation) as viewed in a cross section orthogonal to the axial direction. Hole 34a-34d) is formed in a shape corresponding to the outer surface 32a1-32d1 (34a1-34d1) corresponding to the outer wall 32a1-32d1 (34a1-34d1) and the inner wall 32a2-32d2 (34a2-34d2). Corresponding to the inner side surface, the outer peripheral surface side surface formed in a shape corresponding to the outer peripheral surface side walls 32a3 to 32d3 (34a3 to 34d3), and the central side walls 32a4 to 32d4 (34a4 to 34d4). It has a central surface formed in a shape.
In the present embodiment, in order to increase the amount of magnetic flux, the walls 32a3 to 32d3 (34a3 to 34d3) on the outer peripheral surface side of the first magnet housing holes 32a to 32d (second magnet housing holes 34a to 34d), the first The surface on the outer peripheral surface side of the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) accommodated in the one magnet accommodation holes 32a to 32d (second magnet accommodation holes 34a to 34d) is rotated. It is formed in parallel (including substantially parallel) to the outer peripheral surface of the child core 31 (rotor 30). Further, the walls 32a4 to 32d4 (34a4 to 34d4) on the center side of the first magnet housing holes 32a to 32d (second magnet housing holes 34a to 34d), the first magnet housing holes 32a to 32d (second magnet). Center-side surfaces of the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) accommodated in the accommodation holes 34a to 34d) are formed in parallel (including substantially parallel) to the d axis. .
About the shape of the cross section orthogonal to the axial direction of 1st magnet accommodation hole 32a-32d (2nd magnet accommodation hole 34a-34d) and 1st permanent magnet 33a-33d (2nd permanent magnet 35a-35d). It will be described later.

In the rotor core 31, intermediate bridge portions 36a to 36d are formed between the first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d, and the first magnet housing holes 32a to 32d are formed. First outer peripheral bridge portions 37a1 to 37d1 are formed between the outer peripheral surface of the rotor 30 (the second curved portions 30ab to 30da described above), and the outer periphery of the second magnet housing holes 34a to 34d and the rotor 30. Second outer peripheral bridge portions 37a2 to 37d2 are formed between the surfaces (the second curved portions 30ab to 30da described above). That is, the intermediate bridge portions 36a to 36d are formed by the central walls 32a4 to 32d4 of the first magnet housing holes 32a to 32d and the central walls 34a4 to 34d4 of the second magnet housing holes 34a to 34d. First outer peripheral bridge portions 37a1 to 37d1 are formed by walls 32a3 to 32d3 on the outer peripheral surface side of the magnet housing holes 32a to 32d and the outer peripheral surface of the rotor 30, and the outer peripheral surface side of the second magnet housing holes 34a to 34d. The second outer peripheral bridge portions 37 a 2 to 37 d 2 are formed by the walls 34 a 3 to 34 d 3 and the outer peripheral surface of the rotor 30.
The strength of the rotor 30 is increased by the intermediate bridge portions 36a to 36d, the first outer peripheral bridge portions 37a1 to 37d1, and the second outer peripheral bridge portions 37a2 to 37d2.

Next, the configuration of the first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d will be described.
First, the structure of the magnet accommodation hole of the conventional permanent magnet motor described in Patent Document 1 will be described with reference to FIG. FIG. 6 is a cross-sectional view of a rotor 830 of a conventional permanent magnet motor viewed from a direction orthogonal to the axial direction, and shows a main magnetic pole part c. The main magnetic pole part c is provided with a first magnet accommodation hole 832c and a second magnet accommodation hole 834c. The first magnet accommodation hole 832c (second magnet accommodation hole 834c) includes an outer wall (outer wall) 832c1 (834c1), an inner wall (inner wall) 832c2 (834c2), and an outer peripheral wall (outer end wall). ) 832c3 (834c3) and a central wall (center side end wall) 832c4 (834c4). Further, an intermediate bridge portion 836c is formed between the first magnet housing hole 832c and the second magnet housing hole 834c, and the first bridge is formed between the first magnet housing hole 832c and the outer peripheral surface 830A of the rotor 830. An outer peripheral bridge portion 837c1 is formed, and a second outer peripheral bridge portion 837c2 is formed between the second magnet housing hole 834c and the outer peripheral surface 830A of the rotor 830. A first permanent magnet having a cross-sectional shape corresponding to the cross-sectional shape of the first magnet accommodation hole 832c (second magnet accommodation hole 834c) is formed in the first magnet accommodation hole 832c (second magnet accommodation hole 834c). 833c (second permanent magnet 835c) is accommodated.
In the conventional permanent magnet motor, the wall 832c1 (834c1) outside the first magnet housing hole 832c (second magnet housing hole 834c) provided in the main magnetic pole part c, as viewed in a cross section orthogonal to the axial direction. The inner wall 832c2 (834c2) and the inner wall 832c2 (834c2) are formed in an arc shape centered on a common center point c811 on the d-axis. That is, the outer walls 832c1 and 834c1 are formed in an arc shape having a radius [R811] centered on the center point c811 on the d-axis, and the inner walls 832c2 and 834c2 are centered on the center point c811 on the d-axis. It is formed in an arc shape with a radius [R812].
When a ferrite magnet having a magnetic flux density lower than that of a rare earth magnet is used for the permanent magnet motor having such a configuration, a first magnet housing hole in which a cross-sectional shape viewed from a direction orthogonal to the axial direction is formed in a rectangular shape, and The lengths of the outer walls 832c1 and 834c1 are longer than when the second magnet accommodation hole is used. Accordingly, the first permanent magnet 833c (second permanent magnet 835c) accommodated in the first magnet accommodation hole 832c (second magnet accommodation hole 834c) in the cross section orthogonal to the axial direction shown in FIG. The length of the outer wall corresponding to the outer wall 832c1 (834c1) of the first magnet housing hole 832c (second magnet housing hole 834c) becomes longer, and the amount of magnetic flux increases. However, when the outer wall 832c1 of the first magnet housing hole 832c and the outer wall 834c1 of the second magnet housing hole 834c are formed in an arc shape centered on a common center point, the outer wall There is a limit to increasing the length of 832c1 and 834c1. For this reason, the efficiency equivalent to the case where a rare earth magnet having a high magnetic flux density is used cannot be obtained.

In the present embodiment, in order to increase the outside length of the first magnet accommodation hole and the second magnet accommodation hole provided in the main magnetic pole portion, the first magnet accommodation hole and the second magnet accommodation hole The outer wall is formed in an arc shape centered on a different center point.
The configuration of the magnet housing hole and the permanent magnet according to the present embodiment will be described with reference to FIG. The first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d provided in the main magnetic pole portions a to d have the same configuration, and the first magnet housing holes 32a to 32d and the second magnet housing holes 34a to 34d have the same configuration. The first permanent magnets 33a to 33d and the second permanent magnets 35a to 35d accommodated in the magnet accommodation holes 34a to 34d have the same configuration. For this reason, in the following, it accommodates in the 1st magnet accommodation hole 32c and the 2nd magnet accommodation hole 34c which are provided in the main magnetic pole part c, and the 1st magnet accommodation hole 32c and the 2nd magnet accommodation hole 34c, respectively. The first permanent magnet 33c and the second permanent magnet 35c will be described.
When viewed in a cross section orthogonal to the axial direction, the outer wall 32c1 and the inner wall 32c2 of the first magnet housing hole 32c are formed in an arc shape centered on the center point c11. That is, the outer wall 32c1 is formed in a circular arc shape having a radius [R11] centered on the center point c11, which is concave outward, and the inner wall 32c2 is protruding inward (center direction). The center point c11 is formed in an arc shape having a radius [R12]. In addition, the outer wall 34c1 and the inner wall 34c2 of the second magnet housing hole 34c are formed in an arc shape centered on the center point c21. That is, the outer wall 34c1 is formed in a circular arc shape having a radius [R21] centered on the center point c21, which is concave outward, and the inner wall 34c2 is a center point c21 which protrudes inward. Is formed in a circular arc shape having a radius [R22] centered at.
The first permanent magnet 33c (second permanent magnet 35c) housed in the first magnet housing hole 32c (second magnet housing hole 34c) is a first magnet when viewed in a cross section orthogonal to the axial direction. The outer surface of the magnet housing hole 32c (second magnet housing hole 34c) is formed in a shape corresponding to the outer wall 32c1 (34c1) and the inner wall 32c2 (34c2). Inner surface, outer peripheral surface side surface formed in a shape corresponding to the outer peripheral surface side wall 32c3 (34c3), central side surface formed in a shape corresponding to the central side wall 32c4 (34c4) have. That is, the first permanent magnet 33c has an outer surface formed in an arc shape centered on the center point c11 that is concave outward when viewed in the state accommodated in the first magnet accommodation hole 32c. , And has an inner surface formed in an arc shape centering on a central point c11 that protrudes inward. In addition, the second permanent magnet 35c has an outer surface formed in an arc shape centered on a center point c21 that is concave outward when viewed in the state accommodated in the second magnet accommodation hole 34c. The inner surface is formed in a circular arc shape centering on a center point c21 that protrudes inward.

The center points c11 and c12 and the radii [R11], [R12], [R21], and [R22] are the size (diameter or radius) of the rotor 30, the characteristics and thickness of the permanent magnet, the central bridge portion 36c and the second It is set according to the width, desired efficiency, etc. of the first outer peripheral bridge portion 37c1 and the second outer peripheral bridge portion 37c2. In the present embodiment, the radius [R11] and the radius [R21] are set equal, and the radius [R12] and the radius [R22] are set equal. That is, the first magnet housing hole 32c and the second magnet housing hole 34c, and the first permanent magnet 33c and the second permanent magnet 35c are formed in an arc shape (bow shape). In the present specification, the term “arc shape” is used to encompass a substantially arc shape.
In the present embodiment, the intermediate bridge portions 36a to 36d correspond to the “intermediate bridge portion” of the present invention, the first outer peripheral bridge portions 37a1 to 37d1 correspond to the “first outer peripheral bridge portion” of the present invention, The second outer peripheral bridge portions 37a2 to 37d2 correspond to the “second outer peripheral bridge portion” of the present invention, and the center point c11 of the present invention is “the first arc-shaped first wall of the first magnet housing hole”. Corresponding to the “curvature center point”, the center point c21 corresponds to “the second curvature center point of the arc shape of the outer wall of the second magnet housing hole” of the present invention.

  Thus, in the present embodiment, the outer wall and the inner wall of the first magnet housing hole and the outer wall and the inner wall of the second magnet housing hole are viewed in a cross section orthogonal to the axial direction. Are formed in an arc shape centered on different center points. Thus, when viewed in a cross section orthogonal to the axial direction, the outer wall and the inner wall of the first magnet housing hole, the outer wall and the inner wall of the second magnet housing hole are the common center on the d axis. The length of the outer wall of the first magnet housing hole and the outer wall of the second magnet housing hole can be increased as compared with the case where the arc shape is centered on the point. That is, the length of the outer surface corresponding to the outer wall of the first magnet accommodation hole of the first permanent magnet accommodated in the first magnet accommodation hole, the first permanent magnet accommodated in the second magnet accommodation hole. The length of the outer surface corresponding to the outer wall of the second magnet housing hole of the second permanent magnet can be increased. Therefore, the amount of magnetic flux can be increased and the efficiency can be improved.

In the rotor having the above-described configuration, the magnetic flux generated from the first permanent magnets 33a to 33d accommodated in the first magnet accommodation holes 32a to 32d is generated by the intermediate bridge portions 36c to 36d and the first outer peripheral bridge portion 37a1. The magnetic flux generated from the second permanent magnets 35a to 35d that are short-circuited through the second magnet receiving holes 34a to 34d is generated by the intermediate bridge portions 36c to 36d and the second outer peripheral bridge. Short-circuited through the portions 37a2 to 37d2 (short-circuit magnetic flux is generated).
Here, in the conventional permanent magnet electric motor, as shown in FIG. 6, the first magnet housing hole 832 c has the first magnet housing hole 832 c and the outer wall of the first magnet housing hole 832 c and the second magnet housing hole 834 c. The outer surface of the permanent magnet 833c to be accommodated and the second permanent magnet 835c to be accommodated in the second magnet accommodation hole 834c (the surface facing the outer wall of the magnet accommodation hole) is the outer peripheral surface of the rotor 830. It is formed in parallel (including substantially parallel). Further, the magnetic orientation directions of the first permanent magnet 833c and the second permanent magnet 835c are set along a line passing through the common orientation center point c811 on the d axis (referred to as “radial orientation”). ) For this reason, as shown in FIG. 6, a portion on the center side of the outer wall 832c1 of the first magnet housing hole 832c (a portion on the center side of the outer surface of the first permanent magnet 833c magnetized to the N pole) ) Through the intermediate bridge portion 836c, the portion on the center side of the inner wall 832c2 of the first magnet housing hole 832c (the inner surface of the first permanent magnet 833c magnetized to the south pole) And is short-circuited. Or the magnetic flux which generate | occur | produced from the part by the side of the outer peripheral surface of the outer wall 832c1 of the 1st magnet accommodation hole 832c (the part of the outer peripheral surface side of the outer surface magnetized by the N pole of the 1st permanent magnet 833c). The portion on the outer peripheral surface side of the inner wall 832c2 of the first magnet housing hole 832c (the outer periphery of the inner surface magnetized to the south pole of the first permanent magnet 833c) via the first outer peripheral bridge portion 837c1 Flow to the surface side part) and short-circuited. The same applies to the second outer bridge portion 837c2.
Via the intermediate bridge portion 836c, the first outer peripheral bridge portion 837c1, and the second outer peripheral bridge portion 837c2, the inner wall (or the inner wall) When a magnetic flux (short-circuit magnetic flux) flows from the wall to the outer wall, the amount of magnetic flux (effective magnetic flux) flowing between the main magnetic pole portions a to d and the teeth portion 22 of the stator 20 decreases, and the efficiency decreases.

In the present embodiment, in order to decrease the magnetic flux (short-circuit magnetic flux) flowing between the outer wall and the inner wall of the first magnet accommodation hole and the second magnet accommodation hole and increase the effective magnetic flux amount, The magnetic orientation of the end portions of the first permanent magnet and the second permanent magnet is different from the magnetic orientation of the central portion.
The magnetic orientation direction of the permanent magnet of the present embodiment will be described with reference to FIGS. FIG. 3 is a diagram showing the flow of magnetic flux of the present embodiment, FIG. 4 is a diagram for explaining the magnetic orientation directions of the first and second permanent magnets, and FIG. 5 is the intermediate bridge portion. It is a figure explaining the magnetic flux (short-circuit magnetic flux) which flows through.
Since the magnetic orientation directions of the first permanent magnets 33a to 33d and the second permanent magnets 35a to 35d are the same, in the following, the first permanent magnets accommodated in the first magnet accommodation holes 32c of the main magnetic pole portion c. The magnetic orientation direction of the second permanent magnet 35c accommodated in the magnet 33c and the second magnet accommodation hole 34c will be described with reference to FIG. 4 showing a cross-sectional view seen from a direction orthogonal to the axial direction. The first permanent magnet 33c (second permanent magnet 35c) has an outer wall 32c1 (34c1) outside the first magnet accommodation hole 32c (second magnet accommodation hole 34c) when viewed in a cross section orthogonal to the axial direction. Is magnetized so that one of the outer surface opposite to the inner wall 32c2 (34c2) and the inner surface opposite to the inner wall 32c2 (34c2) is the N pole and the other is the S pole (in a direction intersecting the outer surface and the inner surface). The Below, the center part and the edge part of the 1st permanent magnet 33c (2nd permanent magnet 35c) see the cross section orthogonal to an axial direction of the 1st permanent magnet 33c (2nd permanent magnet 35c). Represents the center and end along the outer surface.
The magnetic orientation direction 33A at the center of the first permanent magnet 33c converges on the orientation center point c11 at the center located at a position outside the outer surface of the first permanent magnet 33c. That is, in the central portion of the first permanent magnet 33c, a line indicating the magnetic orientation direction 33A in the central portion (shown by a solid line in FIG. 4) passes through the central orientation center point c11. . Further, the magnetic orientation direction 33C at the end of the first permanent magnet 33c converges to the orientation center point c13 at the end disposed farther from the center orientation center point c11. That is, at the end portion of the first permanent magnet 33c, the line indicating the magnetic orientation direction 33C at the end portion (shown by a two-dot chain line in FIG. 4) passes through the alignment center point c13 at the end portion. ing. And the magnetic orientation direction 33B of the intermediate part between the center part and edge part of the 1st permanent magnet 33c is the intermediate part arrange | positioned between the orientation center point c11 of a center part, and the orientation center point c13 of an edge part. Is converged to the alignment center point c12. That is, in the intermediate portion of the first permanent magnet 33c, the line indicating the magnetic orientation direction 33B in the intermediate portion (shown by a broken line in FIG. 4) passes through the alignment center point c12 in the intermediate portion. .
Similarly, the magnetic orientation direction 35A at the center of the second permanent magnet 35c converges on the orientation center point c21 at the center disposed at a position outside the outer surface of the second permanent magnet 35c. . That is, at the central portion of the second permanent magnet 35c, a line (shown by a solid line in FIG. 4) indicating the magnetic orientation direction 35A at the central portion is set so as to pass through the alignment center point c21 at the central portion. . Further, the magnetic orientation direction 35C at the end of the second permanent magnet 35c converges to the orientation center point c23 at the end disposed farther from the orientation center point c21 at the center. That is, at the end portion of the second permanent magnet 35c, a line indicating the magnetic orientation direction 35C at the end portion (shown by a two-dot chain line in FIG. 4) passes through the end orientation center point c23. ing. And the magnetic orientation direction 35B of the intermediate part between the center part of the 2nd permanent magnet 35c and an edge part is the intermediate part arrange | positioned between the orientation center point c21 of a center part, and the orientation center point c23 of an edge part. Is converged to the alignment center point c22. That is, in the intermediate portion of the second permanent magnet, a line (indicated by a broken line in FIG. 4) indicating the magnetic orientation direction 35B of the intermediate portion is set so as to pass through the alignment center point c22 of the intermediate portion.
The first permanent magnets 33a to 33d (second permanent magnets 35a to 35d) are magnetized so that one side of the magnetic orientation directions 33A to 33C (35A to 35C) is an N pole and the other side is an S pole. .
In the present embodiment, the magnetic orientation direction 33A corresponds to the “magnetic orientation direction of the central portion of the first permanent magnet” of the present invention, and the orientation center point c11 of the central portion corresponds to the “first permanent magnet of the first permanent magnet” of the present invention. The magnetic orientation direction 33C corresponds to the “magnetic orientation direction of the end portion of the first permanent magnet” of the present invention, and the orientation center point c13 of the end portion corresponds to the “first orientation center point” of the present invention. Corresponds to the “orientation center point of the end portion of one permanent magnet”, the magnetic orientation direction 35A corresponds to the “magnetic orientation direction of the center portion of the second permanent magnet” of the present invention, and the orientation center point c21 of the center portion is The magnetic orientation direction 35C corresponds to the “magnetic orientation direction of the end portion of the second permanent magnet” of the present invention, and corresponds to the “alignment center point of the center portion of the second permanent magnet” of the present invention. The orientation center point c23 corresponds to “the orientation center point of the end portion of the second permanent magnet” of the present invention.

Here, the orientation center point c12 (c22) of the intermediate portion of the first permanent magnet 33c (second permanent magnet 35c) and the orientation center point c13 (c23) of the end portion are the first permanent magnet 33c (second As long as it is set far from the orientation center point c11 (c21) at the center of the permanent magnet 35c), as shown in FIG. 5, the outer side of the first permanent magnet 33c (second permanent magnet 35c) On a line c1 (c2) (indicated by a one-dot chain line in FIGS. 4 and 5) connecting the center point (circumferential center point) c32 (c34) of the surface of the surface and the alignment center point c11 (c21) of the central portion. It is preferable to set (including a mode of setting on the approximate line c1).
Further, the magnetic orientation direction 33C (35C) at the end of the first permanent magnet 33c (second permanent magnet 35c) converges to the orientation center point c13 (c23) at the end located at infinity. May be. That is, in the present embodiment, “the orientation center point of the end portion of the first permanent magnet (second permanent magnet)” includes the orientation center point disposed at infinity. In this case, for example, the magnetic orientation direction 33C (35C) at the end of the first permanent magnet 33c (second permanent magnet 35c) is the outer surface of the first permanent magnet 33c (second permanent magnet 35c). Is parallel (including substantially parallel) to a line c1 (c2) connecting the center point (circumferential center point) c32 (c34) and the center of alignment center c11 (c21).
In addition, the magnetic orientation direction 33B (35B) of the intermediate part of the 1st permanent magnet 33c (2nd permanent magnet 35c) is the orientation center point of the center part of the 1st permanent magnet 33c (2nd permanent magnet 35c). An intermediate orientation center point c12 arranged continuously or stepwise between c11 (c21) and an orientation center point c13 (c23) at the end of the first permanent magnet 33c (second permanent magnet core 35c). You may be comprised so that it may converge to (c22). That is, the orientation direction 33C (35C) of the end portion of the first permanent magnet 33c (second permanent magnet 35c) from the orientation direction 33A (35A) of the center portion of the first permanent magnet 33c (second permanent magnet 35c). ) May change continuously or stepwise. Further, the magnetic orientation direction of the first permanent magnet 33c (second permanent magnet 35c) may be only the magnetic orientation direction 33A (35A) at the center and the magnetic orientation 33C (35C) at the end (intermediate). The magnetic orientation direction of the part may be omitted).
In FIG. 4, the center of orientation of the central portion of the first permanent magnet 33c (second permanent magnet 35c) is set to the outer wall 32c1 of the first magnet housing hole 32c (second magnet housing hole 34c). Although it is arranged at the arc-shaped center point c11 (c21) of (34c1), the orientation center point of the central portion of the first permanent magnet 33c (second permanent magnet 35c) can be arranged at an appropriate position.

As described above, in the present embodiment, the first permanent magnets 33a to 33d (the second permanent magnets accommodated in the second magnet accommodation holes 34a to 34d) accommodated in the first magnet accommodation holes 32a to 32d. The magnetic orientation direction 33A (35A) in the central portion of the magnets 35a to 35d is converged to the orientation central point c11 (c21) in the central portion. As a result, the gap magnetic flux density distribution can be made close to a sine wave shape, and the occurrence of vibration and sound due to cogging torque can be suppressed.
Further, end portions of the first permanent magnets 33a to 33d (second permanent magnets 35a to 35d accommodated in the second magnet accommodation holes 34a to 34d) accommodated in the first magnet accommodation holes 32a to 32d, respectively. The magnetic orientation direction 33C (35C) converges to the orientation center point c13 (c23) at the end located farther (including infinity) than the orientation center point c11 (c21) at the center. As a result, as shown in FIG. 5, the center-side wall 32c4 of the first magnet housing hole 32c (the surface on the center side magnetized to the north pole of the first permanent magnet 33c) via the intermediate bridge portion 36c. ) And the inner wall 32c2 of the first magnet housing hole 32c (the inner surface magnetized by the south pole of the first permanent magnet 33c) flows, but the first magnet The outer wall 32c1 of the housing hole 32c (the outer surface magnetized by the N pole of the first permanent magnet 33c) and the inner wall 32c2 of the first magnet housing hole 32c (the S pole of the first permanent magnet 33c) Magnetic flux (short-circuit magnetic flux) is less likely to flow between the inner surface and the inner surface. Further, the central side wall 34c4 (the surface on the central side magnetized to the north pole of the second permanent magnet 35c) of the second magnet accommodation hole 34c and the second magnet accommodation hole via the intermediate bridge portion 36c. Magnetic flux (short-circuit magnetic flux) flows between the inner wall 34c2 of 34c (the inner surface magnetized by the south pole of the second permanent magnet 35c), but the outer wall 34c1 of the second magnet housing hole 34c. (The outer surface magnetized to the north pole of the second permanent magnet 35c) and the inner wall 34c2 of the second magnet housing hole 34c (the inner surface magnetized to the south pole of the second permanent magnet 35c) ), It is difficult for magnetic flux (short-circuit magnetic flux) to flow. Similarly, as shown in FIG. 3, the outer walls of the first and second magnet housing holes 32a to 32d and 34a to 34d are interposed via the first and second outer peripheral bridge portions 37a1 to 37d1 and 37a2 to 37d2. 32a1 to 32d1 and 34a1 to 34d1 (the outer surfaces of the first and second permanent magnets 33a to 33d and 35a to 35d) and the inner wall 32a2 of the first and second magnet housing holes 32a to 32d and 34a to 34d The magnetic flux (short-circuit magnetic flux) hardly flows between ˜32d2 and 34a2 to 34d2 (the inner surfaces of the first and second permanent magnets 33a to 33d and 35a to 35d).
Therefore, a decrease in the amount of magnetic flux (effective magnetic flux) flowing between the main magnetic pole portions a to d and the teeth portion 22 of the stator 20 can be prevented, and the efficiency can be improved.

In the first embodiment, each of the main magnetic pole portions a to d has a one-layer structure permanent in which only one set of first and second magnet accommodation holes (a set of first and second permanent magnets) is provided. Although the magnet motor has been described, the present invention can also be configured as a multi-layered permanent magnet motor. A second embodiment configured as a permanent magnet motor having a multilayer structure will be described below.
The permanent magnet motor of the second embodiment is configured by the stator 20 of the first embodiment shown in FIG. 1 and the rotor 130 shown in FIG. This embodiment is configured as a permanent magnet motor having a two-layer structure.
In the present embodiment, as in the first embodiment, the outer circumferential surface of the rotor 130 (rotor core 131) is an arc having a radius [Rd] centered on the center point O of the rotor on the d axis. Arcs having a radius [Rq] centered on center points (Pbc, Pcd) separated in the opposite direction from the center point O of the rotor 130 on the q axis, and the first curved portions 130a to 130d formed in the shape The second curved portions 130ab to 130da formed in a shape are alternately connected.
In the rotor 130 (rotor core 131), a first layer first magnet housing hole 142a to 142d and a first layer magnet housing hole are formed in each main magnetic pole portion a to d. A set of second magnet housing holes 144a to 144d is provided. Also, the second layer first magnet housing holes 146a to 146d and the second layer second magnet constituting the second layer magnet housing hole inside (center side) from the first layer magnet housing hole. Accommodating holes 148a to 148d are provided. The first permanent magnets 143a to 143d, 145a to 145d, 147a to 147d, and 149a to 149d are accommodated in the magnet accommodation holes, respectively. Intermediate bridge portions 136a1 to 136d1 of the first layer are formed between the first magnet housing holes 142a to 142d of the first layer and the second magnet housing holes 144a to 144d of the first layer. The first outer peripheral bridge portions 137a1 to 137d1 are formed between the first magnet housing holes 142a to 142d and the outer peripheral surface of the rotor 130, and the first layer second magnet housing holes 144a to 144d and Between the outer peripheral surface of the rotor 130, second outer peripheral bridge portions 137a2 to 137d2 of the first layer are formed. Between the second layer first magnet housing holes 146a to 146d and the second layer second magnet housing holes 148a to 148d, second layer intermediate bridge portions 136a2 to 136d2 are formed, and the second layer first magnet housing holes 146a to 146d are formed. The first outer peripheral bridge portions 137a3 to 137d3 of the second layer are formed between the first magnet accommodating holes 146a to 146d and the outer peripheral surface of the rotor 130, and the second layer second magnet accommodating holes 148a to 148d Between the outer peripheral surface of the rotor 130, second outer peripheral bridge portions 137a4 to 137d4 of the second layer are formed.
Each magnet accommodation hole is formed by the outer wall, the inner wall, the outer peripheral surface side wall, and the center side wall, as in the first embodiment. In addition, each permanent magnet includes an outer wall, an inner wall, an outer peripheral surface side wall, an outer surface formed in a shape corresponding to the central wall, an inner surface, and an outer peripheral surface surface. And has a central surface.

In the present embodiment, the outer wall and the inner wall of the first magnet accommodation hole of each layer are formed in an arc shape centering on the first center point, and the second magnet accommodation hole of each layer is It is formed in an arc shape centering on a second center point different from the center point of one. That is, as shown in FIG. 7, the outer and inner walls of the first magnet housing hole 142c of the first layer and the first magnet of the second layer provided in the main magnetic pole portion c. The outer wall and the inner wall of the accommodation hole 146c are each formed in an arc shape having radii [R111], [R112], [R113], and [R114] around the center point c111. Further, the outer wall and the inner wall of the second magnet housing hole 144c of the first layer and the outer wall and the inner wall of the second magnet housing hole 148c of the second layer provided in the main magnetic pole part c. Each of the walls is formed in an arc shape having radii [R121], [R122], [R123], and [R124] around the center point c121.
The magnetic orientation direction of each permanent magnet can also be set as in the first embodiment. Moreover, it can also comprise in the multilayered structure of three or more layers.

In this embodiment, since it has a multilayer structure, the reluctance torque due to the rotor core between layers can be used, and the efficiency can be improved. Further, by adopting a multilayer structure, the amount of magnetic flux flowing through the teeth portion when the switching portion (connection point portion) of the main magnetic pole portions a to d and the auxiliary magnetic pole portions ab to da passes through the teeth portion of the stator. A sudden change can be prevented.
Further, similarly to the first embodiment, the magnet housing holes provided on the outer peripheral side (in FIG. 7, the first magnet housing holes 142a to 142d of the first layer constituting the first layer and the first Since the length of the outer wall of the one-layer second magnet housing holes 144a to 144d) can be increased, the amount of magnetic flux can be increased.
Further, when the magnetic orientation direction of the permanent magnet is set as in the first embodiment, the short-circuit magnetic flux through the intermediate bridge portion, the first outer peripheral bridge portion, and the second outer peripheral bridge portion can be reduced. And the amount of effective magnetic flux can be increased.
Further, by configuring the outer peripheral surface by connecting the first curved portion and the second curved portion having different radii of curvature, the same effects as those of the first embodiment are obtained.
Therefore, by using this embodiment, as in the first embodiment, even when a ferrite magnet or the like having a lower magnetic flux density than a rare earth magnet is used, the permanent magnet has the same efficiency as that using a rare earth magnet. A magnet motor can be obtained.

The method of configuring the outer peripheral surface of the rotor by the first curved portion and the second curved portion having different curvature radii is not limited to the methods of the first and second embodiments. The third embodiment of the present invention will be described below.
The third embodiment includes the stator 20 of the first embodiment shown in FIG. 1 and the rotor 230 shown in FIG. The rotor 230 is the same as that of the first embodiment except that the method of configuring the outer peripheral surface is different from that of the rotor 30 of the first embodiment.
In the present embodiment, the first curved portions 230a to 230d corresponding to the main magnetic pole portions a to d of the rotor 230 have a radius [R1] centered on the center point O of the rotor 230 (rotor core 231). The second curve portions 230ab to 230da corresponding to the auxiliary magnetic pole portions ab to da have a radius [R2 (<R1) centered on the center point O of the rotor 230 (rotor core 231). ] Arc shape.

When the magnetic flux generated from the permanent magnet accommodated in the magnet accommodation hole is short-circuited through the teeth portion of the stator, the magnetic flux flowing through the teeth portion fluctuates and cogging torque is generated. When cogging torque is generated, sound and vibration are generated. Below, 4th implementation which prevents that the magnetic flux which generate | occur | produces from a permanent magnet is short-circuited via the teeth part of a stator is demonstrated.
The fourth embodiment includes the stator 20 of the first embodiment shown in FIG. 1 and the rotor 330 shown in FIG. The rotor 330 has the same configuration as the rotor 30 of the first embodiment except that notches are formed in the first and second outer peripheral bridge portions.
In the present embodiment, the outer peripheral surface of the rotor 330 is formed by first curved portions 330a to 330d corresponding to the main magnetic pole portions a to d and second curved portions 330ab to 330da corresponding to the auxiliary magnetic pole portions ab to da. It is configured.
The rotor 330 is provided with first magnet housing holes 332a to 332d and second magnet housing holes 334a to 334d. Intermediate bridge portions 336a to 336d are formed between the first magnet housing holes 332a to 332d and the second magnet housing holes 334a to 334d, and the first magnet housing holes 332a to 332d and the rotor 330 (rotor core) are formed. 331) are formed with first outer peripheral bridge portions 337a1 to 337d1 between the outer peripheral surfaces (second curved portions 330ab to 330da in FIG. 9), and the second magnet housing holes 334a to 334d and the rotor 330 ( Second outer peripheral bridge portions 337a2 to 337d2 are formed between the rotor core 331) and the rotor core 331).
Further, in the present embodiment, the first outer peripheral bridge portions 337a1 to 337d1 (second outer peripheral bridge portions 337a2 to 337d2) have first magnet receiving holes 332a to 332d (second magnet receiving holes 334a to 334d). ) Are notched portions 331a1 to 331d1 (331a2 to 331d2) at locations facing the outer peripheral surface side wall. The notches 331a1 to 331d1 and 331a2 to 331d2 are formed in a concave shape in the outward direction by notching from the line along the second curved line portions 330ab to 330da to the center side.
The circumferential lengths of the notches 331a1 to 331d1 and 331a2 to 331d2 are set to be equal to or larger than the width of the base portion 22a of the teeth portion 22 of the stator, and preferably longer than the circumferential length of the teeth tip surface 22d of the teeth portion 22. It is preferable.

In the fourth embodiment. Although notches are formed in the first and second outer bridge portions, holes can also be formed. FIG. 10 shows a fifth embodiment in which holes are formed in the first and second outer peripheral bridge portions.
The fifth embodiment includes the stator 20 of the first embodiment shown in FIG. 1 and the rotor 430 shown in FIG. The rotor 430 has the same configuration as the rotor 30 of the first embodiment, except that holes are formed in the first and second outer peripheral bridge portions.
In the present embodiment, the first outer peripheral bridge portions 437a1 to 437d1 (second outer peripheral bridge portions 437a2 to 437d2) have first magnet receiving holes 432a to 432d (second magnet receiving holes 434a to 434d). Holes 431a1 to 431d1 (431a2 to 431d2) are formed at locations facing the outer peripheral surface side wall. The holes 431a1 to 431d1 and 431a2 to 431d2 may be configured as voids or may be configured by filling a nonmagnetic material.
The circumferential lengths of the holes 431a1 to 431d1 and 431a2 to 431d2 are set to be not less than the width of the base portion 22a of the teeth portion 22 of the stator, preferably not less than the circumferential length of the tooth tip surface 22d of the teeth portion 22. Is preferred.

In the fourth and fifth embodiments, the magnetic flux generated from the first and second permanent magnets housed in the first and second magnet housing holes is passed through the teeth portion of the stator. A short circuit can be prevented. Thereby, the amount of effective magnetic flux can be increased and efficiency can be improved.
In addition, the torque pulsation is reduced by reducing the fluctuation of the reluctance torque, or the magnetic attraction force in the radial direction between the rotor and the stator is reduced by reducing the magnetic flux short circuit amount at the end of the permanent magnet. Noise and vibration can be reduced.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions are possible.
The magnet housing hole and the permanent magnet housed in the magnet housing hole include a magnet housing hole in which at least the outer wall is formed in an arc shape and an outer surface formed in a shape corresponding to the outer wall of the magnet housing hole. Any permanent magnet may be used.
In addition, the configuration in which the magnetic orientation at the end of the permanent magnet is set so as to be along a line passing through the orientation center at the end far from the center at the center can be omitted.
Moreover, the structure which forms a notch part and a hole in the location which opposes the wall by the side of the outer peripheral surface of a magnet accommodation hole in an outer periphery bridge part can also be abbreviate | omitted.
Each configuration described in the embodiment can be used alone, or a plurality selected as appropriate can be used in combination.
The present invention is not limited to a permanent magnet motor, and can be configured as a permanent magnet rotating machine having various configurations.

DESCRIPTION OF SYMBOLS 10 Permanent magnet motor 20 Stator 21 Yoke part 22 Teeth part 23 Slot 30, 130, 230, 330, 430, 830 Rotor 30a-30d, 130a-130d, 230a-230d, 330a-330d, 430a-430d 1st Curved portions 30ab-30da, 130ab-130da, 230ab-230da, 330ab-330da, 430ab-430da Second curved portions 31, 131, 231, 431 Rotor cores 32a-32d, 34a-34d, 142a-142d, 144a- 144d, 146a-146d, 148a-148d, 232a-232d, 234a-234d, 332a-332d, 334a-334d, 432a-432d, 434a-434d, 832c, 834c Magnet receiving holes 32a1- 32d1, 142a1, 144a1, 146a1, 148a1, 832c1, 834c1 Outer walls 32a2 to 32d2, 142a2, 144a2, 146a2, 148a2, 832c2, 834c2 Inner walls 32a3 to 32d3, 142a3, 144a3, 146a3, 148a3, 832c3 Surface side walls 32a4 to 32d4, 142a4, 144a4, 146a4, 148a4, 832c4, 834c4 Central side walls 33a to 33d, 35a to 35d, 143a to 143d, 145a to 145d, 147a to 147d, 149a to 149d, 233a to 233d 235a-235d, 333a-333d, 335a-335d, 433a-433d, 435a-435d, 833c, 835c permanent magnets 36a-36d, 36a1-136d1, 136a2-136d2, 236a-236d, 336a-336d, 436a-436d, 836c Intermediate bridge portions 37a1-37d1, 37a2-37d2, 137a1-137d1, 137a2-137d2, 137a3-137d3, 137a4-137d4, 237a1- 237d1, 237a2 to 237d2, 337a1 to 337d1, 337a2 to 337d2, 437a1 to 437d1, 437a2 to 437d2, 837c1, 837c2 outer peripheral bridge portions 38a to 38d, 138a to 138d, 238a to 238d, 338a to 338d, 438a to 438d caulking pin insertion holes 40, 140, 240, 340, 440 Rotating shaft insertion holes 331a1-331d1, 331a2-331d2 Notch 431a ~431d1,431a2~431d2 hole 830A peripheral surface

Claims (4)

The rotor includes a stator and a rotor, and the rotor is alternately arranged with a main magnetic pole portion and an auxiliary magnetic pole portion in the circumferential direction when viewed in a cross section orthogonal to the axial direction. A permanent magnet rotating machine in which a housing hole is provided and a permanent magnet is housed in the magnet housing hole;
The outer circumferential surface of the rotor is formed in a first curved shape that intersects with the d-axis line of the main magnetic pole portion and has a protrusion facing outward when viewed in a cross section orthogonal to the axial direction. And a second curve portion that is formed in a second curve shape that intersects the q-axis line of the auxiliary magnetic pole portion and the protrusion faces outward, and the second curve portion. The radius of curvature of the curve shape is set to be larger than the radius of curvature of the first curve shape,
The main magnetic pole portion is formed by an outer wall that is concave outward, an inner wall that protrudes inward, an outer peripheral wall, and a central wall when viewed in a cross section orthogonal to the axial direction. The first magnet housing hole and the second magnet housing hole are formed with an intermediate bridge portion between the central wall of the first magnet housing hole and the central wall of the second magnet housing hole. A first outer bridge portion is formed between the outer peripheral surface of the first magnet housing hole and the outer peripheral surface of the rotor, and the outer peripheral wall of the second magnet housing hole and the wall It is arranged so that the second outer peripheral bridge portion is formed between the outer peripheral surfaces of the rotor,
The outer wall and the inner wall of the first magnet housing hole are formed in an arc shape centered on the first curvature center point,
The outer wall and the inner wall of the second magnet housing hole are centered on a second curvature center point different from the first curvature center point, and the outer wall and the inner wall of the first magnet housing hole respectively. Formed in an arc shape with a radius equal to the radius of the wall of
The positions of the first curvature center point and the second curvature center point are such that the lengths of the outer wall of the first magnet accommodation hole and the outer wall of the second magnet accommodation hole have the same diameter. Using a rotor and a permanent magnet of the same thickness, the outer wall of the first magnet housing hole and the outer wall of the second magnet housing hole are arc-shaped around the common center of curvature on the d axis. Is set to be longer than the maximum length of the outer wall of the first magnet housing hole and the outer wall of the second magnet housing hole when
The first magnet accommodation hole includes an outer surface formed in an arc shape corresponding to an arc shape of an outer wall of the first magnet accommodation hole, and an inner wall of the first magnet accommodation hole. A first permanent magnet having an inner surface formed in an arc shape corresponding to the arc shape is accommodated;
The second magnet housing hole includes an outer surface formed in an arc shape corresponding to an arc shape of the outer wall of the second magnet housing hole, and an inner wall of the second magnet housing hole. A permanent magnet rotating machine comprising a second permanent magnet having an inner surface formed in an arc shape corresponding to the arc shape. The permanent magnet rotating machine according to claim 1,
The first curved portion is formed in an arc shape centered on the center of curvature on the d-axis, and the second curved portion is formed in an arc shape centered on the center of curvature on the q-axis. A permanent magnet rotating machine. The permanent magnet rotating machine according to claim 2,
The first curved portion is formed in an arc shape with a center point of the rotor as a center point of curvature, and the second curved portion is in a direction opposite to the second curved portion from the center point of the rotor. A permanent magnet rotating machine characterized in that it is formed in a circular arc shape having a center of curvature at a point far from the center. The permanent magnet rotating machine according to any one of claims 1 to 3,
A set of the first magnet accommodation hole and the second magnet accommodation hole is provided in multiple layers in the radial direction of the rotor,
The outer wall and the inner wall of the first magnet housing hole of each layer are formed in an arc shape centering on the first curvature center point, and the outer wall and the inner wall of the second magnet housing hole of each layer are formed. The wall is formed in the circular arc shape centering on the said 2nd curvature center point, The permanent magnet rotary machine characterized by the above-mentioned.

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