CN220254218U

CN220254218U - Rotor core, rotating electrical machine, and driving device

Info

Publication number: CN220254218U
Application number: CN202321294542.5U
Authority: CN
Inventors: 古郡彩实
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2022-06-07
Filing date: 2023-05-25
Publication date: 2023-12-26
Anticipated expiration: 2033-05-25
Also published as: JP2023179082A

Abstract

The utility model provides a rotor core, a rotating electrical machine, and a driving device. One embodiment of the rotor core according to the present utility model is a rotor core of a rotor rotatable about a central axis, comprising: a plurality of magnet holding portions arranged in a circumferential direction, each of the plurality of magnet holding portions having a pair of first magnet holes adjacent to each other in the circumferential direction; and a first through hole penetrating the rotor core in the axial direction, the first through hole having a portion located radially inward of the first magnet hole. The pair of first magnet holes extend in directions that are circumferentially separated from each other as viewed in the axial direction from the radially inner side toward the radially outer side. The first through hole is provided at a position overlapping with a virtual line extending in the radial direction through the circumferential centers of the circumferentially adjacent magnet holding parts, and is formed in an asymmetric shape with the virtual line interposed therebetween when viewed in the axial direction.

Description

Rotor core, rotating electrical machine, and driving device

Technical Field

The present utility model relates to a rotor core, a rotating electrical machine, and a driving device.

Background

Rotor cores having through holes are known. For example, patent document 1 describes a rotor core having a circular hollow portion as the rotor core portion.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2005-184957

Disclosure of Invention

Technical problem to be solved by the utility model

The through-hole is provided for the purpose of, for example, weight reduction of the rotor core. The larger the through hole is, the lighter the rotor core can be, but on the other hand, the larger the through hole is, the lower the strength of the rotor core is, which is a problem. Therefore, it is difficult to enlarge the through-hole to some extent or more, and the rotor core may not be sufficiently lightweight.

In view of the above, an object of the present utility model is to provide a rotor core having a structure that ensures rigidity and can be further reduced in weight, and a rotary electric machine provided with such a rotor core.

Technical proposal adopted for solving the technical problems

One embodiment of the rotor core according to the present utility model is a rotor core of a rotor rotatable about a central axis, comprising: a plurality of magnet holding parts arranged in a circumferential direction, the plurality of magnet holding parts respectively having a pair of first magnet holes adjacent to each other in the circumferential direction; and a first through hole penetrating the rotor core in an axial direction, the first through hole having a portion located radially inward of the first magnet hole. The pair of first magnet holes extend in directions that are circumferentially separated from each other as viewed in the axial direction from the radially inner side toward the radially outer side. The first through hole is provided at a position overlapping a virtual line extending in a radial direction through a circumferential center between the circumferentially adjacent magnet holding parts, and is in an asymmetric shape sandwiching the virtual line when viewed in the axial direction.

One embodiment of the rotating electrical machine of the present utility model includes: a rotor having the above rotor core; and a stator that is opposed to the rotor with a gap therebetween in a radial direction.

One embodiment of the driving device of the present utility model includes: the rotating electrical machine; and a gear mechanism connected to the rotating electric machine.

Effects of the utility model

According to one aspect of the present utility model, in a rotating electrical machine and a driving device, the rotor core can be made lighter while ensuring rigidity of the rotor core.

Drawings

Fig. 1 is a diagram schematically showing a driving device of an embodiment.

Fig. 2 is a sectional view showing a rotor of an embodiment.

Fig. 3 is a cross-sectional view showing a part of a rotor core of an embodiment.

Fig. 4 is a sectional view showing another part of the rotor core of an embodiment.

Fig. 5 is a cross-sectional view showing a further part of a rotor core and a part of a shaft of an embodiment.

(symbol description)

10 rotors; 30 rotor core; 30h of a second through hole; 31 a magnet holding part; 33a, 33b, 34 recesses; a 40 magnet; 41a, 41b first magnets; 42a, 42b second magnets; 51a, 51b first magnet holes; 52a, 52b second magnet holes; a 60-turn motor; a stator 61; a 70 gear mechanism; 90. 90a, 90b first through holes; 91a, 93a first inner wall portion; 91b, 93b second inner wall portions; 91c, 93c third inner wall portions; 91d, 93d fourth inner wall portions; 91e, 93e fifth inner wall portions; 91f, 93f sixth inner wall portions; 92a, 94a first connection; 92b, 94b second connection portions; 92c, 94c third connection; 92d, 94d fourth connection; 92e, 94e fifth connection; 92f, 94f sixth connection; 100 driving means; c1 a first imaginary circle; c2 a second imaginary circle; a J central axis; LM1 first tangent; LM2 second tangent; lq imaginary line

Detailed Description

In the following description, a description will be given of a vertical direction with reference to a positional relationship in a case where the driving device of the embodiment is mounted on a vehicle on a horizontal road surface. That is, at least in the case where the driving device is mounted on a vehicle on a horizontal road surface, the relative positional relationship with respect to the vertical direction described in the following embodiment may be satisfied.

In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is the vertical direction. The +Z side is the upper side in the vertical direction, and the-Z side is the lower side in the vertical direction. In the following description, the upper side in the vertical direction will be simply referred to as "upper side", and the lower side in the vertical direction will be simply referred to as "lower side". The X-axis direction is a direction orthogonal to the Z-axis direction, which is a front-rear direction of a vehicle to which the driving device is mounted. In the following embodiment, the +x side is the front side in the vehicle, and the-X side is the rear side in the vehicle. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction, and is a vehicle width direction that is a left-right direction of the vehicle. In the following embodiment, the +y side is the left side in the vehicle, and the-Y side is the right side in the vehicle. The front-rear direction and the left-right direction are horizontal directions orthogonal to the vertical direction.

The positional relationship in the front-rear direction is not limited to the positional relationship in the following embodiment, and the +x side may be the rear side of the vehicle, and the-X side may be the front side of the vehicle. In this case, the +y side is the right side of the vehicle, and the-Y side is the left side of the vehicle. In the present specification, "parallel direction" includes a substantially parallel direction, and "orthogonal direction" includes a substantially orthogonal direction.

The central axis J appropriately shown in the drawing is a virtual axis extending in a direction intersecting the vertical direction. More specifically, the center axis J extends in the Y-axis direction orthogonal to the vertical direction, that is, in the left-right direction of the vehicle. In the following description, unless otherwise specified, a direction parallel to the central axis J is simply referred to as an "axial direction", a radial direction centered on the central axis J is simply referred to as a "radial direction", and a circumferential direction centered on the central axis J, that is, a direction around the central axis J is simply referred to as a "circumferential direction". In the following description, the left side is one axial side, and the right side is the other axial side.

The driving device 100 of the present embodiment shown in fig. 1 is a driving device that is mounted on a vehicle and rotates an axle 73. The vehicle mounted with the drive device 100 is a motor-powered vehicle such as a Hybrid Electric Vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an Electric Vehicle (EV). As shown in fig. 1, the driving device 100 includes: a rotating electric machine 60; a gear mechanism 70 connected to the rotary electric machine 60; a housing 80 that houses the rotating electric machine 60 and the gear mechanism 70 therein; and a control device 64 that controls the rotating electrical machine 60. In the present embodiment, the rotary electric machine 60 is a motor.

The housing 80 houses the rotating electric machine 60 and the gear mechanism 70 therein. The housing 80 includes a motor housing 81 that houses the rotary electric machine 60 therein, and a gear housing 82 that houses the gear mechanism 70 therein. In the present embodiment, the oil O is stored in the motor case 81 and the gear case 82.

The gear mechanism 70 transmits the rotation of the rotary electric machine 60 to an axle 73 of the vehicle. The gear mechanism 70 has a reduction gear 71 connected to the rotary electric machine 60, and a differential gear 72 connected to the reduction gear 71. The axle 73 is connected to the differential gear 72.

The rotating electric machine 60 includes: a rotor 10, the rotor 10 being rotatable about a central axis J; and a stator 61, the stator 61 being opposed to the rotor 10 with a gap therebetween in the radial direction. In the present embodiment, the stator 61 is located radially outward of the rotor 10. The stator 61 has a stator core 62 and a plurality of coils 63 mounted on the stator core 62.

As shown in fig. 2, the rotor 10 includes a shaft 20, a rotor core 30, and a plurality of magnets 40. As shown in fig. 1, the shaft 20 extends in the axial direction centering on the central axis J. The left end of the shaft 20 (+y side) protrudes into the gear housing 82. As shown in fig. 2, in the present embodiment, the shaft 20 is a hollow shaft having a cylindrical shape centered on the central axis J. The shaft 20 has a groove portion 21 recessed radially inward from the outer periphery of the shaft 20. Although not shown, the groove 21 extends in the axial direction. The groove portions 21 are provided in a pair in the radial direction with the central axis J therebetween.

The rotor core 30 is fixed to the outer peripheral surface of the shaft 20. The rotor core 30 has a substantially cylindrical shape centered on the central axis J. The rotor core 30 has a second through hole 30h, and the second through hole 30h penetrates the rotor core 30 in the axial direction. The center axis J passes through the inside of the second through hole 30h. In the present embodiment, the second through hole 30h is a substantially circular hole centered on the central axis J. The shaft 20 passes through the second through hole 30h in the axial direction. The inner peripheral surface of the second through hole 30h is fixed to the outer peripheral surface of the shaft 20. For example, the shaft 20 is pressed into the second through hole 30h.

A protrusion 32 protruding radially inward is provided at the inner edge of the second through hole 30h. Although not shown, the protrusion 32 extends in the axial direction. The protrusions 32 are provided in a pair with the central axis J therebetween in the radial direction. The pair of protrusions 32 are fitted into the pair of grooves 21. Thereby, the shaft 20 and the rotor core 30 are hooked to each other in the circumferential direction, and the shaft 20 and the rotor core 30 are restrained from rotating relative to each other in the circumferential direction.

A pair of concave portions 33a, 33b and a concave portion 34 recessed radially outward are provided at the inner edge of the second through hole 30h. The pair of concave portions 33a, 33b are provided in two pairs in the radial direction with the central axis J interposed therebetween. The pair of concave portions 33a and 33b are provided so as to sandwich the protruding portions 32 in the circumferential direction adjacent to both sides of the protruding portions 32 in the circumferential direction. The concave portions 34 are provided with a pair of radially sandwiching the central axis J. The pair of concave portions 34 are disposed so as to sandwich the central axis J in a radial direction orthogonal to the radial direction in which the pair of protruding portions 32 sandwich the central axis J, as viewed in the axial direction. A pair of recesses 34 extend in the circumferential direction. By providing the concave portions 33a, 33b, 34, a part of stress generated on the shaft 20 when the shaft 20 is pressed into the second through hole 30h can be released from a portion of the shaft 20 facing the concave portions 33a, 33b, 34 in the radial direction. Therefore, the shaft 20 is easily pushed into the second through hole 30h.

In fig. 2, a radial direction in which the pair of protrusions 32 sandwich the central axis J is shown by a straight line LS1, and a radial direction orthogonal to the radial direction in which the pair of protrusions 32 sandwich the central axis J is shown by a straight line LS 2. The straight line LS1 is an imaginary line extending in the radial direction passing through the circumferential center and the central axis J of the pair of protrusions 32 as viewed in the axial direction. The straight line LS2 is an imaginary line extending in the radial direction passing through the circumferential center and the central axis J in the pair of concave portions 34 as viewed in the axial direction. Straight lines LS1 and LS2 are orthogonal to each other.

The rotor core 30 is made of magnetic material. As shown in fig. 1, the rotor core 30 is configured by stacking a plurality of plate members 30a in the axial direction. The plate member 30a is a plate-like member having a plate surface facing in the axial direction. The plate member 30a is substantially disc-shaped with the central axis J as the center. The plate member 30a is made of a rolled steel material formed by rolling in a predetermined direction. The material of the plate member 30a is, for example, an electromagnetic steel plate. In the present embodiment, a plurality of plate members 30a are rotatably stacked. That is, the plurality of plate members 30a include two or more plate members 30a whose rolling directions are different from each other. The rolling direction of the plate member 30a is a predetermined direction in which the rolled steel material, which is the material of the plate member 30a, is rolled. In the present embodiment, each time one or more plate members 30a are stacked, the one or more plate members 30a are stacked so as to be rotated by 90 ° about the center axis J with respect to the plate member 30a stacked immediately before.

As shown in fig. 2, the rotor core 30 has a plurality of magnet holding portions 31 arranged in a circumferential direction. A plurality of magnet holding portions 31 are provided at the radially outer portion in the rotor core 30 a. The plurality of magnet holding portions 31 are arranged at equal intervals throughout the entire circumference in the circumferential direction. In the present embodiment, the magnet holding portions 31 are provided with eight.

As shown in fig. 3, each of the plurality of magnet holding parts 31 includes: a pair of first magnet holes 51a, 51b adjacent to each other in the circumferential direction; and a pair of second magnet holes 52a, 52b located radially outside the pair of first magnet holes 51a, 51b and adjacent to each other in the circumferential direction. That is, in the present embodiment, the magnet holding portions 31 are provided with a total of four magnet holes of the pair of first magnet holes 51a and 51b and the pair of second magnet holes 52a and 52b, respectively. In the present embodiment, a pair of first magnet holes 51a, 51b and a pair of second magnet holes 52a, 52b penetrate the rotor core 30 in the axial direction. The pair of first magnet holes 51a and 51b and the pair of second magnet holes 52a and 52b may be holes having bottoms at axial ends.

As shown in fig. 2, one magnet 40 is disposed in each of the four magnet holes in each magnet holding portion 31. The kind of the magnet 40 is not particularly limited. The magnet 40 may be, for example, a neodymium magnet or a ferrite magnet. The magnet 40 has, for example, a rectangular parallelepiped shape long in the axial direction. The magnet 40 extends, for example, from one axial end portion to the other axial end portion of the rotor core 30.

The plurality of magnets 40 includes a pair of first magnets 41a, 41b disposed in the pair of first magnet holes 51a, 51b, respectively, and a pair of second magnets 42a, 42b disposed in the pair of second magnet holes 52a, 52b, respectively. Each magnet 40 is fixed in each magnet hole. The method of fixing each magnet 40 into each magnet hole is not particularly limited. For example, each magnet 40 may be fixed to each magnet hole by caulking a part of the rotor core 30, may be fixed to each magnet hole by resin filled in a part of each magnet hole other than the part where the magnet 40 is arranged, or may be fixed to each magnet hole by a foam sheet arranged in a part of each magnet hole other than the part where the magnet 40 is arranged.

As shown in fig. 2, the magnetic pole portion 10P is constituted by one magnet holding portion 31 and a plurality of magnets 40 arranged in a plurality of magnet holes provided in the one magnet holding portion 31. The plurality of magnetic pole portions 10P are arranged at equal intervals throughout the circumference in the circumferential direction. In the present embodiment, the magnetic pole portions 10P are provided with eight. The plurality of magnetic pole portions 10P include a plurality of magnetic pole portions 10N having a magnetic pole of N poles at the outer peripheral surface of the rotor core 30 and a plurality of magnetic pole portions 10S having a magnetic pole of S poles at the outer peripheral surface of the rotor core 30, respectively. In the present embodiment, four magnetic pole portions 10N and 10S are provided. The four magnetic pole portions 10N and the four magnetic pole portions 10S are alternately arranged in the circumferential direction. The structure of each magnetic pole portion 10P is the same except that the magnetic poles of the outer peripheral surface of the rotor core 30 are different and the circumferential positions are different.

As shown in fig. 3, at the magnetic pole portion 10P, the first magnet hole 51a and the first magnet hole 51b are arranged to sandwich the magnetic pole center line Ld in the circumferential direction. The magnetic pole center line Ld is an imaginary line passing through the circumferential center of the magnetic pole portion 10P and the center axis J and extending in the radial direction. The circumferential center of the magnetic pole portion 10P is the circumferential center of the magnet holding portion 31. A magnetic pole center line Ld is provided for each magnetic pole portion 10P. The magnetic pole center line Ld passes through the d-axis of the rotor 10 as viewed in the axial direction. The direction in which the magnetic pole center line Ld extends is the d-axis direction of the rotor 10. The first magnet hole 51a and the first magnet hole 51b are arranged to be line-symmetrical with respect to the magnetic pole center line Ld as viewed in the axial direction.

The pair of first magnet holes 51a, 51b extend in the following directions when viewed in the axial direction: and directions separated from each other in the circumferential direction from the radially inner side toward the radially outer side. That is, the circumferential distance between the first magnet hole 51a and the first magnet hole 51b becomes larger as going from the radially inner side toward the radially outer side. The pair of first magnet holes 51a, 51b are arranged along the following shape when viewed in the axial direction: the V-shape expands in the circumferential direction as going radially outward.

The first magnet hole 51a has a magnet housing hole portion 51c, an inner hole portion 51d, and an outer hole portion 51e. The magnet housing hole portion 51c is a rectangular hole long in the direction in which the first magnet hole 51a extends when viewed in the axial direction. The inner hole 51d is connected to a radially inner end of the ends of the magnet accommodating hole 51c in the direction in which the magnet accommodating hole 51c extends, as viewed in the axial direction. The outer hole 51e is connected to a radially outer end of the ends of the magnet accommodating hole 51c in the direction in which the magnet accommodating hole 51c extends, as viewed in the axial direction.

The first magnet hole 51b has a magnet housing hole portion 51f, an inner hole portion 51g, and an outer hole portion 51h. The magnet housing hole portion 51f is a rectangular hole long in the direction in which the first magnet hole 51b extends when viewed in the axial direction. The inner hole 51g is connected to a radially inner end of the ends of the magnet accommodating hole 51f in the direction in which the magnet accommodating hole 51f extends, as viewed in the axial direction. The outer hole 51h is connected to a radially outer end of the ends of the magnet accommodating hole 51f in the direction in which the magnet accommodating hole 51f extends, as viewed in the axial direction.

The inner hole 51d and the inner hole 51g are arranged at intervals in the circumferential direction so as to sandwich the magnetic pole center line Ld in the circumferential direction. The portion of each inner hole 51d, 51g closest to the other inner hole in the circumferential direction is the portion of the pair of first magnet holes 51a, 51b closest to the other first magnet hole in the circumferential direction. In the present embodiment, the portion of the pair of first magnet holes 51a, 51b closest to the other first magnet hole in the circumferential direction is a radially outer portion of the inner hole portions 51d, 51 g. The edge of each of the inner hole 51d and the inner hole 51g on the side closer to the other inner hole is formed in a substantially circular arc shape recessed toward the other inner hole when viewed in the axial direction.

As shown in fig. 2, the pair of first magnets 41a, 41b disposed in the pair of first magnet holes 51a, 51b are disposed in a V-shape that expands in the circumferential direction as going radially outward when viewed in the axial direction. The first magnet 41a is disposed in the magnet accommodating hole portion 51c of the first magnet hole 51 a. The first magnet 41b is disposed in the magnet accommodating hole portion 51f of the first magnet hole 51 b. The inner hole portions 51d and 51g and the outer hole portions 51e and 51h are, for example, hollow portions, and constitute magnetic flux barrier portions. The inner holes 51d and 51g and the outer holes 51e and 51h may be filled with a nonmagnetic material such as a resin, or the magnetic flux barrier may be formed by the holes and the nonmagnetic material such as a resin filled in the holes. In the present specification, the term "magnetic flux barrier" refers to a portion capable of suppressing the flow of magnetic flux. That is, the magnetic flux does not easily pass through each magnetic flux barrier portion.

The pair of second magnet holes 52a, 52b are located radially outward of the pair of first magnet holes 51a, 51b, respectively. The second magnet hole 52a is located radially outward of the first magnet hole 51 a. The second magnet hole 52b is located radially outward of the first magnet hole 51 b. The pair of second magnet holes 52a, 52b are located between the circumferential directions of the pair of first magnet holes 51a, 51b with respect to each other. At the magnetic pole portion 10P, the second magnet hole 52a and the second magnet hole 52b are arranged circumferentially across the magnetic pole center line Ld. The second magnet hole 52a and the second magnet hole 52b are arranged to be line-symmetrical with respect to the magnetic pole center line Ld as viewed in the axial direction.

The pair of second magnet holes 52a, 52b extend in the following directions when viewed in the axial direction: and directions separated from each other in the circumferential direction from the radially inner side toward the radially outer side. That is, the circumferential distance between the second magnet hole 51a and the second magnet hole 52b becomes larger as going from the radially inner side toward the radially outer side. The pair of second magnet holes 52a, 52b are arranged along the following shape when viewed in the axial direction: the V-shape expands in the circumferential direction as going radially outward.

As shown in fig. 3, the second magnet hole 52a has a magnet housing hole portion 52c, an inner hole portion 52d, and an outer hole portion 52e. The magnet housing hole portion 52c is a rectangular hole long in the direction in which the second magnet hole 52a extends when viewed in the axial direction. The inner hole portion 52d is connected to a radially inner end portion of the end portions of the magnet accommodating hole portion 52c in the direction in which the magnet accommodating hole portion 52c extends, as viewed in the axial direction. The outer hole portion 52e is connected to a radially outer end portion of the end portions of the magnet accommodating hole portion 52c in the direction in which the magnet accommodating hole portion 52c extends, as viewed in the axial direction.

The second magnet hole 52b has a magnet receiving hole portion 52f, an inner hole portion 52g, and an outer hole portion 52h. The magnet housing hole portion 52f is a rectangular hole long in the direction in which the second magnet hole 52b extends when viewed in the axial direction. The inner hole portion 52g is connected to a radially inner end portion of the end portions of the magnet accommodating hole portion 52f in the direction in which the magnet accommodating hole portion 52f extends, as viewed in the axial direction. The outer hole portion 52h is connected to a radially outer end portion of the end portions of the magnet accommodating hole portion 52f in the direction in which the magnet accommodating hole portion 52f extends, as viewed in the axial direction.

The inner hole 52d and the inner hole 52g are arranged at intervals in the circumferential direction so as to sandwich the magnetic pole center line Ld in the circumferential direction. The interval in the circumferential direction between the inner hole 52d and the inner hole 52g is smaller than the interval in the circumferential direction between the inner hole 51d and the inner hole 51 g. The portion of each inner hole 52d, 52g closest to the other inner hole in the circumferential direction is the portion of the pair of second magnet holes 52a, 52b closest to the other second magnet hole in the circumferential direction. In the present embodiment, the portion of the pair of second magnet holes 52a, 52b closest to the other second magnet hole in the circumferential direction is a radially outer portion of the inner hole portions 52d, 52 g. The edge of each of the inner hole 52d and the inner hole 52g on the side closer to the other inner hole is formed in a substantially circular arc shape recessed toward the other inner hole when viewed in the axial direction.

As shown in fig. 2, the pair of second magnets 42a, 42b disposed in the pair of second magnet holes 52a, 52b are disposed in a V-shape that expands in the circumferential direction as going radially outward when viewed in the axial direction. That is, in each magnetic pole portion 10P of the present embodiment, two pairs of magnets 40 arranged in a V-shape when viewed in the axial direction are provided so as to be aligned in the radial direction. The second magnet 42a is disposed in the magnet receiving hole portion 52c of the second magnet hole 52 a. The second magnet 42b is disposed in the magnet receiving hole portion 52f of the second magnet hole 52 b. The inner hole portions 52d, 52g and the outer hole portions 52e, 52h are, for example, hollow portions, and constitute magnetic flux barrier portions. The inner holes 52d, 52g and the outer holes 52e, 52h may be filled with a nonmagnetic material such as a resin, or the magnetic flux barrier may be formed by the holes and the nonmagnetic material such as a resin filled in the holes.

In the present specification, the term "direction in which the magnet hole extends when viewed in the axial direction" refers to, for example, a direction in which the long side of the magnet accommodating hole portion in which the magnet is accommodated as in the first magnet holes 51a and 51b of the present embodiment extends when viewed in the axial direction, in the case where the magnet accommodating hole portion is rectangular when viewed in the axial direction. That is, for example, in the present embodiment, the "direction in which the first magnet hole 51a extends when viewed in the axial direction" refers to the direction in which the long side of the rectangular magnet accommodating hole portion 51c extends when viewed in the axial direction.

As shown in fig. 2, the rotor core 30 has a first through hole 90 penetrating the rotor core 30 in the axial direction. The first through hole 90 is provided in a radially inner portion of the rotor core 30. The first through holes 90 are provided in plurality at intervals in the circumferential direction. In the present embodiment, eight first through holes 90 are provided. Each of the first through holes 90 is disposed radially inward of each of the circumferentially adjacent magnet holding portions 31. Each of the first through holes 90 is located radially inward of the first magnet hole 51a of one of the circumferentially adjacent magnet holding parts 31 and the first magnet hole 51b of the other magnet holding part 31. Thus, the first through hole 90 has a portion located radially inward of the first magnet holes 51a, 51 b.

The plurality of first through holes 90 includes a first through hole 90a and a first through hole 90b. The first through holes 90a and the first through holes 90b are each provided in plural. In the present embodiment, four first through holes 90a and four first through holes 90b are provided. The first through holes 90a and the first through holes 90b are alternately arranged in the circumferential direction. The first through hole 90a and the first through hole 90b are each in a shape inverted in the circumferential direction. Therefore, in the following description, only the first through hole 90a may be representatively described.

In the present embodiment, when the number of magnet holding portions 31 is N, the plurality of first through holes 90 are arranged symmetrically N/2 times around the center axis J. Accordingly, even if the plurality of first through holes 90 rotate by [ 360/(N/2) ] ° around the central axis J, the plurality of first through holes 90 overlap with the entire plurality of first through holes 90 before rotation in the axial direction. Therefore, when the plurality of plate members 30a constituting the rotor core 30 are rotated and laminated at [ 360/(N/2) ] °, the first through holes 90 can be formed while the shape of each plate member 30a is made identical. In the present embodiment, since N, which is the number of magnet holding parts 31, is 8, the plurality of first through holes 90 are arranged four times symmetrically around the center axis J. Therefore, the plurality of plate members 30a can be rotationally stacked by 90 ° about the center axis J.

As shown in fig. 3, the first through hole 90a is provided at a position overlapping the virtual line Lq when viewed in the axial direction. The virtual line Lq is a virtual line extending in the radial direction passing through the circumferential centers of the circumferentially adjacent magnet holding parts 31. The imaginary line Lq passes through the q-axis of the rotor 10 when viewed in the axial direction. The direction in which the virtual line Lq extends is the q-axis direction of the rotor 10. An imaginary line Lq is provided between each of the magnet holding parts 31. The direction in which the magnetic pole center line Ld extends and the direction in which the virtual line Lq extends are directions intersecting each other. The magnetic pole center line Ld and the virtual line Lq are alternately arranged in the circumferential direction. In the present embodiment, the circumferential centers of the circumferentially adjacent magnet holding parts 31 are the circumferential centers in the rotor core 30 in the portion between the first magnet hole 51a of one magnet holding part 31 and the circumferential direction of the first magnet hole 51b of the other magnet holding part 31.

The first through hole 90a has an asymmetric shape with respect to the virtual line Lq when viewed in the axial direction. Therefore, the first through hole 90a can be made less deformable than when the first through hole 90a is formed in a shape symmetrical to the virtual line Lq by a circle, a simple polygon, or the like. Accordingly, even if the rotor core 30 is made lighter by increasing the size of the first through hole 90a to some extent, the rotor core 30 is less likely to deform around the first through hole 90 a. Therefore, the rigidity of the rotor core 30 can be ensured, and the rotor core 30 can be made lighter. Therefore, even when the rotor 10 rotates at a high speed or the like, a relatively large centrifugal force is applied to the rotor core 30, and deformation of the rotor core 30 can be suppressed.

The phrase "the first through hole 90a is asymmetric with respect to the virtual line Lq when viewed in the axial direction" means that the following shape is not required: the shape of the portion of the first through hole 90a located at the one side in the circumferential direction from the virtual line Lq and the shape of the portion of the first through hole 90a located at the other side in the circumferential direction from the virtual line Lq are formed to be symmetrical to each other with respect to the virtual line Lq as the axis of symmetry when viewed in the axial direction.

In the present embodiment, the size of the portion of the first through hole 90a located at the one side in the circumferential direction from the virtual line Lq and the size of the portion of the first through hole 90a located at the other side in the circumferential direction from the virtual line Lq are different from each other. In the following description of the first through hole 90a, one side in the circumferential direction is a side toward which the arrow θ shown in fig. 3 to 5 faces (+θ side), and the other side in the circumferential direction is an opposite side (- θ side) to the side toward which the arrow θ shown in fig. 3 to 5 faces. Arrow θ shows the circumferential direction. In the present embodiment, the size of the portion of the first through hole 90a located at one side in the circumferential direction (+θ side) from the virtual line Lq is larger than the size of the portion of the first through hole 90a located at the other side in the circumferential direction (- θ side) from the virtual line Lq.

As shown in fig. 4, the inner wall of the first through hole 90a has a first inner wall portion 91a, a second inner wall portion 91b, a third inner wall portion 91c, a fourth inner wall portion 91d, a fifth inner wall portion 91e, a sixth inner wall portion 91f, a first connection portion 92a, a second connection portion 92b, a third connection portion 92c, a fourth connection portion 92d, a fifth connection portion 92e, and a sixth connection portion 92f when viewed in the axial direction. In this way, by making the inner wall of the first through hole 90a have a shape having six inner wall portions and six connecting portions, the first through hole 90a can be made less deformable than in the case where the shape of the first through hole 90a is a simple shape. Thereby, the rigidity of the rotor core 30 is easily and more appropriately ensured. Each inner wall portion and each connecting portion of the first through hole 90a are wall portions facing the inside of the first through hole 90a, respectively. The inner edge of the first through hole 90a is formed by each inner wall and each connecting portion when viewed in the axial direction.

The first connection portion 92a is a portion connecting the first inner wall portion 91a and the second inner wall portion 91 b. The second connection portion 92b is a portion connecting the second inner wall portion 91b and the third inner wall portion 91 c. The third connecting portion 92c is a portion connecting the third inner wall portion 91c and the fourth inner wall portion 91 d. The fourth connecting portion 92d is a portion connecting the fourth inner wall portion 91d and the fifth inner wall portion 91 e. The fifth connecting portion 92e is a portion connecting the fifth inner wall portion 91e and the sixth inner wall portion 91 f. The sixth connecting portion 92f is a portion connecting the sixth inner wall portion 91f and the first inner wall portion 91 a. In the present embodiment, the first connecting portion 92a, the second connecting portion 92b, the fourth connecting portion 92d, the fifth connecting portion 92e, and the sixth connecting portion 92f have an arc shape recessed outward of the first through hole 90a when viewed in the axial direction. In the present embodiment, the third connecting portion 92c has an arc shape protruding inward of the first through hole 90a when viewed in the axial direction. Therefore, compared with the case where each connecting portion connecting the inner wall portions to each other forms an acute angle portion, stress generated at the inner wall of the first through hole 90a is easily dispersed and received at each connecting portion. This makes it possible to more appropriately prevent the first through hole 90a from being deformed, and to more appropriately ensure the rigidity of the rotor core 30.

The first connection portion 92a is a portion located at the most radially outer side of the inner wall of the first through hole 90 a. In the present embodiment, the first connecting portion 92a has an arc shape recessed radially outward when viewed in the axial direction. The first connection portion 92a is provided at a position where at least a part thereof overlaps the virtual line Lq when viewed in the axial direction. In the present embodiment, the virtual line Lq overlaps with the circumferential center of the first connecting portion 92a when viewed in the axial direction. The portion of the first connection portion 92a that overlaps with the virtual line Lq when viewed in the axial direction is a portion of the first connection portion 92a that is located at the most radially outer side. An end portion of one side (+θ side) of the first connection portion 92a in the circumferential direction is located radially inward of the first magnet hole 51a of one of the circumferentially adjacent magnet holding portions 31. An end portion of the first connecting portion 92a on the other side (- θ side) in the circumferential direction is located radially inward of the first magnet hole 51b of the other one of the circumferentially adjacent magnet holding portions 31.

In the description of the first through hole 90a, one of the magnet holding parts 31 is the magnet holding part 31 located on one side (+θ side) in the circumferential direction among the circumferentially adjacent magnet holding parts 31. In the description of the first through hole 90a, the other magnet holding portion 31 is the magnet holding portion 31 located on the other side (- θ side) in the circumferential direction among the circumferentially adjacent magnet holding portions 31.

The first inner wall portion 91a is connected to one circumferential side (+θ side) of the first connecting portion 92 a. The first inner wall portion 91a is located at the circumferential side of the virtual line Lq. The first inner wall portion 91a extends radially inward from the first connecting portion 92a as viewed in the axial direction. More specifically, the first inner wall portion 91a extends linearly from the end portion on the circumferential side of the first connecting portion 92a to the radially inner side and the circumferential side as viewed in the axial direction. That is, the first inner wall portion 91a is located on one circumferential side as it goes radially inward.

The first inner wall portion 91a is located at a position separated from the radially inner side of the first magnet hole 51a of one of the circumferentially adjacent magnet holding portions 31. The first inner wall portion 91a extends in a direction in which the first magnet hole 51a extends when viewed in the axial direction. Therefore, a magnetic circuit through which magnetic flux flows can be appropriately formed in the rotor core 30 at a portion between the first magnet hole 51a and the first inner wall portion 91 a. The first inner wall portion 91a extends parallel to a direction in which the long side of the magnet accommodating hole portion 51c in the first magnet hole 51a extends when viewed in the axial direction. In fig. 4, a direction in which the first inner wall portion 91a extends when viewed in the axial direction is shown by a straight line L1, and a direction in which the long side of the magnet accommodating hole portion 51c in the first magnet hole 51a extends when viewed in the axial direction is shown by a straight line La. The straight line L1 and the straight line La are virtual lines extending parallel to each other. The straight line L1 is overlapped with the first inner wall portion 91a as a whole when viewed in the axial direction. The straight line La entirely overlaps the long side located radially inward among the long sides of the magnet accommodating hole 51c when viewed in the axial direction.

The second inner wall portion 91b is connected to the other side (- θ side) of the first connecting portion 92a in the circumferential direction. The second inner wall portion 91b is located at the other side in the circumferential direction from the virtual line Lq. The second inner wall portion 91b extends radially inward from the first connecting portion 92a as viewed in the axial direction. More specifically, the second inner wall portion 91b extends radially inward and linearly from the end portion on the other side in the circumferential direction of the first connecting portion 92a as viewed in the axial direction. That is, the second inner wall portion 91b is located on the other side in the circumferential direction as it goes radially inward. The first inner wall portion 91a and the second inner wall portion 91b extend in the following directions when viewed in the axial direction: the first connection portions 92a provided at positions where a part overlaps with the virtual line Lq are separated from each other in the circumferential direction as they are directed radially inward. Therefore, it is easy to dispose the first inner wall portion 91a and the second inner wall portion 91b on the radially inner side of each of the two pairs of circumferentially adjacent first magnet holes 51a, 51 b. This can prevent the first through hole 90a from being disposed too close to any one of the circumferentially adjacent magnet holding portions 31, and can easily and appropriately ensure the rigidity of the entire rotor core 30 in the circumferential direction. Further, a magnetic circuit through which magnetic flux flows is easily formed appropriately between the first magnet hole 51a and the first inner wall portion 91a in the rotor core 30 and between the first magnet hole 51b and the second inner wall portion 91b in the rotor core 30.

The second inner wall portion 91b is located at a position separated from the radially inner side of the first magnet hole 51b of the other one of the circumferentially adjacent magnet holding portions 31. The second inner wall portion 91b extends in a direction in which the first magnet hole 51b extends when viewed in the axial direction. Therefore, a magnetic circuit through which magnetic flux flows can be appropriately formed in the rotor core 30 at a portion between the first magnet hole 51b and the second inner wall portion 91 b. The second inner wall portion 91b extends parallel to a direction in which the long side of the magnet accommodating hole portion 51f in the first magnet hole 51b extends when viewed in the axial direction. In fig. 4, the direction in which the second inner wall portion 91b extends is shown by a straight line L2, and the direction in which the long side of the magnet accommodating hole portion 51f in the first magnet hole 51b extends is shown by a straight line Lb. The straight line L2 and the straight line Lb are virtual lines extending parallel to each other. The straight line L2 overlaps the second inner wall portion 91b as viewed in the axial direction. The straight line Lb overlaps the long side located radially inward of the long sides of the magnet accommodating hole 51f when viewed in the axial direction.

The second inner wall portion 91b is smaller in size in the direction in which the second inner wall portion 91b extends than the first inner wall portion 91a is in the direction in which the first inner wall portion 91a extends, as viewed in the axial direction. The radially inner end of the second inner wall portion 91b is located radially outward of the radially inner end of the first inner wall portion 91 a. The radially inner end of the second inner wall portion 91b is located closer to the virtual line Lq than the radially inner end of the first inner wall portion 91 a.

The second connecting portion 92b is connected to a radially inner end portion of the second inner wall portion 91 b. In the present embodiment, the second connecting portion 92b is formed in an arc shape recessed toward the other side (- θ side) in the circumferential direction when viewed in the axial direction. The second connecting portion 92b is located at the other side in the circumferential direction from the virtual line Lq. The end of the second connecting portion 92b on the opposite side to the side connected to the second inner wall portion 91b is located radially inward of the radially inward end of the second inner wall portion 91b and is located on the side closer to the virtual line Lq in the circumferential direction, that is, on the circumferential side (+θ side).

The third inner wall portion 91c is connected to the second inner wall portion 91b via the second connecting portion 92 b. The third inner wall portion 91c extends from the second connecting portion 92b in a direction approaching the first inner wall portion 91a in the circumferential direction. In the present embodiment, the third inner wall portion 91c extends in an arc shape from an end portion of the second connecting portion 92b on the opposite side to the side connected to the second inner wall portion 91b to the circumferential direction side (+θ side). Fig. 3 shows a first virtual circle C1 overlapping the third inner wall portion 91C extending in an arc shape when viewed in the axial direction. That is, the third inner wall portion 91C is arranged along the first virtual circle C1 when viewed in the axial direction. The first virtual circle C1 is a virtual circle centered on the central axis J. The third inner wall portion 91c is located at the other side (- θ side) in the circumferential direction than the virtual line Lq.

The third connecting portion 92c and an end portion of the third inner wall portion 91c on the opposite side (+θ side) to the side connected to the second connecting portion 92b are connected. In the present embodiment, the third connecting portion 92c has an arc shape protruding outward in the radial direction toward one circumferential direction (+θ side) when viewed in the axial direction. The third connecting portion 92c is located at the other side (- θ side) in the circumferential direction than the virtual line Lq. The end portion of the third connecting portion 92c on the opposite side to the side connected to the third inner wall portion 91c is located radially inward of the end portion of the side connected to the third inner wall portion 91c and is located on the side closer to the virtual line Lq in the circumferential direction, that is, on the circumferential side (+θ side).

The fourth inner wall portion 91d is connected to the third inner wall portion 91c via a third connecting portion 92 c. The fourth inner wall portion 91d extends in a straight line from the end portion on the circumferential side (+θ side) of the third connecting portion 92c to the circumferential side and radially inward as viewed in the axial direction. The fourth inner wall portion 91d is located on one circumferential side as it faces radially inward. The fourth inner wall portion 91d is provided at a position where a part thereof overlaps with the virtual line Lq when viewed in the axial direction. In the present embodiment, the virtual line Lq overlaps with the circumferential center portion of the fourth inner wall portion 91d when viewed in the axial direction. The radially outer end of the fourth inner wall portion 91d, that is, the end connected to one side of the third connecting portion 92c, is located at the other side (- θ side) in the circumferential direction from the virtual line Lq. The end of the fourth inner wall 91d on the inner side in the radial direction, that is, the end on the opposite side to the side connected to the third connecting portion 92c is located on the circumferential side from the virtual line Lq.

The fourth inner wall portion 91d extends in a direction in which the first inner wall portion 91a extends when viewed in the axial direction. Here, as described above, the first inner wall portion 91a extends in the direction in which the first magnet hole 51a extends when viewed in the axial direction. Therefore, in the present embodiment, the first inner wall portion 91a and the fourth inner wall portion 91d extend in the direction in which the first magnet hole 51a extends, respectively, when viewed in the axial direction. Thereby, the stress generated in the direction in which the first magnet hole 51a extends can be appropriately received by the first inner wall portion 91a and the fourth inner wall portion 91 d. Therefore, the first through hole 90a can be made more appropriately less deformable, and the rigidity of the rotor core 30 can be ensured more appropriately.

In fig. 4, a direction in which the fourth inner wall portion 91d extends when viewed in the axial direction is shown by a straight line L4. The straight line L4 is an imaginary line extending parallel to the straight lines L1 and La. The straight line L4 overlaps the fourth inner wall portion 91d as viewed in the axial direction. The fourth inner wall portion 91d is disposed opposite to the first inner wall portion 91a through the inside of the first through hole 90 a. The portion of the inner wall of the first through hole 90a, which is constituted by the third inner wall portion 91c, the third connecting portion 92c, and the fourth inner wall portion 91d, forms a convex portion 95 that protrudes inward of the first through hole 90a when viewed in the axial direction.

The fourth connecting portion 92d and the end portion of the fourth inner wall portion 91d on the opposite side (+θ side) to the side connected to the third connecting portion 92c are connected. In the present embodiment, the fourth connecting portion 92d has an arc shape recessed inward in the radial direction toward the other side (- θ side) in the circumferential direction as viewed in the axial direction. The fourth connecting portion 92d is located at one side (+θ side) in the circumferential direction from the virtual line Lq. The end portion of the fourth connecting portion 92d on the opposite side to the side connected to the fourth inner wall portion 91d is located radially inward of the end portion of the side connected to the fourth inner wall portion 91d and at a position circumferentially away from the virtual line Lq, that is, at a circumferential side (+θ side).

The fifth inner wall portion 91e is connected to the fourth inner wall portion 91d via a fourth connecting portion 92 d. The fifth inner wall portion 91e extends in an arc shape from an end portion of the fourth connecting portion 92d on the opposite side to the side connected to the fourth inner wall portion 91d to the circumferential direction side (+θ side). The fifth inner wall portion 91e is located radially inward of the third inner wall portion 91 c. The fifth inner wall portion 91e is located on the circumferential side of the third inner wall portion 91 c. The fifth inner wall portion 91e is located at the circumferential side from the virtual line Lq.

Fig. 3 shows a second virtual circle C2 overlapping the fifth inner wall portion 91e extending in an arc shape when viewed in the axial direction. That is, the fifth inner wall portion 91e is arranged along the second virtual circle C2 when viewed in the axial direction. The second virtual circle C2 is a virtual circle centered on the central axis J. That is, the first virtual circle C1 and the second virtual circle C2 are concentric circles. Therefore, the stress generated in the direction around the center of the first virtual circle C1 and the second virtual circle C2 is easily and appropriately received by the third inner wall portion 91C arranged along the first virtual circle C1 when viewed in the axial direction and the fifth inner wall portion 91e arranged along the second virtual circle C2 when viewed in the axial direction. This makes it possible to more appropriately prevent the first through hole 90a from being deformed, and to more appropriately secure the rigidity of the rotor core 30. In the present embodiment, since the first virtual circle C1 and the second virtual circle C2 are virtual circles centered on the central axis J, the third inner wall portion 91C and the fifth inner wall portion 91e easily receive the circumferential stress generated in the rotor core 30 when the rotor 10 rotates, and the rotor core 30 can be more appropriately restrained from being deformed when the rotor 10 rotates.

The fifth connecting portion 92e and the end portion of the fifth inner wall portion 91e on the opposite side (+θ side) to the side connected to the fourth connecting portion 92d are connected. In the present embodiment, the fifth connecting portion 92e has an arc shape recessed radially inward toward one circumferential side (+θ side) as viewed in the axial direction. The fifth connecting portion 92e is located at one side (+θ side) in the circumferential direction from the virtual line Lq. The end portion of the fifth connecting portion 92e on the opposite side to the side connected to the fifth inner wall portion 91e is located radially outward of the end portion of the side connected to the fifth inner wall portion 91e and at a position circumferentially away from the virtual line Lq, that is, at a position circumferentially on the side (+θ side).

The sixth connecting portion 92f is connected to the radially inner end of the first inner wall portion 91 a. In the present embodiment, the sixth connecting portion 92f is formed in an arc shape recessed toward one circumferential direction (+θ side) as viewed in the axial direction. The sixth connecting portion 92f is located at one side (+θ side) in the circumferential direction from the virtual line Lq. The end portion of the sixth connecting portion 92f on the opposite side to the side connected to the first inner wall portion 91a is located radially inward of the end portion on the side connected to the first inner wall portion 91a and is located on the side away from the virtual line Lq in the circumferential direction, that is, on the circumferential side (+θ side).

The sixth inner wall portion 91f extends in the radial direction as viewed in the axial direction. The sixth inner wall portion 91f is connected to the fifth inner wall portion 91e via a fifth connecting portion 92 e. The sixth inner wall portion 91f is connected to the first inner wall portion 91a via a sixth connecting portion 92 f. As shown in fig. 3, the sixth inner wall portion 91f extends in parallel with a direction in which the magnetic pole center line Ld located at a position closest to the sixth inner wall portion 91f extends, of the magnetic pole center lines Ld, as viewed in the axial direction. In fig. 3, a direction in which the sixth inner wall portion 91f extends when viewed in the axial direction is shown by a straight line L6. The straight line L6 is an imaginary line extending in parallel with the magnetic pole center line Ld located closest to the sixth inner wall portion 91f among the magnetic pole center lines Ld. The straight line L6 overlaps the sixth inner wall portion 91f as viewed in the axial direction. The straight line L6 overlaps the first magnet hole 51 and the second magnet hole 52a when viewed in the axial direction. The sixth inner wall portion 91f is located at one side (+θ side) in the circumferential direction from the virtual line Lq. The sixth inner wall portion 91f is provided at a position closer to the virtual line Lq than the circumferential end portion on the side closer to the magnetic pole center line Ld in the first magnet hole 51 and the second magnet hole 52a in the circumferential direction.

The sixth inner wall portion 91f extends along a first tangential line LM1 when viewed in the axial direction, the first tangential line LM1 being tangent to a portion of the pair of first magnet holes 51a, 51b that is closest to the other first magnet hole in the circumferential direction. In fig. 3, a first tangential line LM1 is shown that is tangential to a portion of the first magnet hole 51a that is closest to the first magnet hole 51b in the circumferential direction. The first tangential line LM1 is an imaginary line extending in parallel with the magnetic pole center line Ld passing between the pair of first magnet holes 51a, 51 b. The first tangent line LM1 and the straight line L6 extend parallel to each other. In the present embodiment, the first tangential line LM1 is tangent to an edge portion extending in a substantially circular arc shape on the side (+θ side) close to the inner hole portion 51g of the first magnet hole 51b, of the inner hole portion 51d of the first magnet hole 51a, as viewed in the axial direction.

The first tangent LM1 extends along a second tangent LM2 when viewed in the axial direction, the second tangent LM2 being tangent to a portion of the pair of second magnet holes 52a, 52b that is closest to the other second magnet hole in the circumferential direction. That is, the sixth inner wall portion 91f extends along the first tangential line LM1 and the second tangential line LM 2. By disposing the sixth inner wall portion 91f in this manner, stress generated in the rotor core 30 in the radial direction passing through the portion between the circumferential directions of the pair of first magnet holes 51a, 51b and the portion between the circumferential directions of the pair of second magnet holes 52a, 52b can be easily received by the sixth inner wall portion 91 f. This can ensure the rigidity of the rotor core 30 more appropriately. In the present embodiment, the stress generated in the radial direction in which the magnetic pole center line Ld extends can be easily received by the sixth inner wall portion 91 f. Therefore, the first through hole 90a can be made more unlikely to deform, and the rigidity of the rotor core 30 can be further ensured more appropriately.

In fig. 3, a second tangent LM2 tangent to a portion of the second magnet hole 52a that is closest to the second magnet hole 52b in the circumferential direction is shown. The second tangential line LM2 is an imaginary line extending parallel to the magnetic pole center line Ld passing between the pair of second magnet holes 52a, 52 b. The first tangent line LM1 and the second tangent line LM2 extend parallel to each other. In the present embodiment, the second tangent line LM2 is tangent to an edge portion extending in a substantially circular arc shape on the side (+θ side) close to the inner hole portion 52g of the second magnet hole 52b, of the inner hole portion 52d of the second magnet hole 52a, as viewed in the axial direction.

In the present embodiment, the radius of curvature of the first connecting portion 92a and the radius of curvature of the second connecting portion 92b are the same as each other. Therefore, the shape of the first through hole 90a as a whole is easily set to a shape that is easily adapted to receive stress generated in the rotor core 30. This makes it possible to more appropriately prevent the first through hole 90a from being deformed, and to more appropriately ensure the rigidity of the rotor core 30.

In the present embodiment, the radius of curvature of the fourth connecting portion 92d, the radius of curvature of the fifth connecting portion 92e, and the radius of curvature of the sixth connecting portion 92f are the same as each other. Therefore, the shape of the first through hole 90a as a whole is easily set to a shape that is more likely to receive stress generated in the rotor core 30. This makes it possible to more appropriately prevent the first through hole 90a from being deformed, and to more appropriately ensure the rigidity of the rotor core 30.

In the present embodiment, the radius of curvature of the third connecting portion 92c is smaller than the radius of curvature of the fourth connecting portion 92d, the radius of curvature of the fifth connecting portion 92e, and the radius of curvature of the sixth connecting portion 92 f. Therefore, the radius of curvature of the third connecting portion 92c can be made relatively small. In this way, the convex portion 95, which is a portion of the first through hole 90a including the third inner wall portion 91c, the third connecting portion 92c, and the fourth inner wall portion 91d, is easily protruded inward of the first through hole 90a when viewed in the axial direction. Therefore, the first through hole 90a can be made smaller at the convex portion 95, and the rigidity at the portion of the rotor core 30 adjacent to the convex portion 95 can be appropriately improved.

In the present embodiment, the radius of curvature of the fourth connecting portion 92d, the radius of curvature of the fifth connecting portion 92e, and the radius of curvature of the sixth connecting portion 92f are smaller than the radius of curvature of the first connecting portion 92a and the radius of curvature of the second connecting portion 92 b. Therefore, the radius of curvature of the fourth connecting portion 92d, the radius of curvature of the fifth connecting portion 92e, and the radius of curvature of the sixth connecting portion 92f can be made relatively small. This can prevent the portion of the first through hole 90a that is formed by the fourth inner wall portion 91d, the fourth connecting portion 92d, the fifth inner wall portion 91e, the fifth connecting portion 92e, the sixth inner wall portion 91f, and the sixth connecting portion 92f from excessively sagging outward of the first through hole 90a when viewed in the axial direction. Accordingly, the first through hole 90a can be appropriately prevented from becoming excessively large, and the rigidity of the rotor core 30 can be appropriately prevented from being lowered.

As shown in fig. 5, the inner wall of the first through hole 90b has a first inner wall portion 93a, a second inner wall portion 93b, a third inner wall portion 93c, a fourth inner wall portion 93d, a fifth inner wall portion 93e, a sixth inner wall portion 93f, a first connection portion 94a, a second connection portion 94b, a third connection portion 94c, a fourth connection portion 94d, a fifth connection portion 94e, and a sixth connection portion 94f when viewed in the axial direction. The inner wall portions and the connecting portions in the first through hole 90b are arranged symmetrically in the circumferential direction with respect to the inner wall portions and the connecting portions in the first through hole 90a, respectively, with the magnetic pole center line Ld interposed therebetween. The distance d1 in the circumferential direction between the pair of first through holes 90a and 90b in which the second connecting portion 92b and the second connecting portion 94b are arranged to face each other in the circumferential direction is larger than the distance d2 in the circumferential direction between the pair of first through holes 90a and 90b in which the sixth inner wall portion 91f and the sixth inner wall portion 93f are arranged to face each other in the circumferential direction.

At least a part of the concave portions 33a, 33b, 34 is arranged at the same position in the circumferential direction as the third inner wall portion 91c or the third inner wall portion 93 c. Here, the third inner wall portions 91c, 93c are located radially outward of the fifth inner wall portions 91e, 93 e. Therefore, the third inner wall portions 91c and 93c are disposed at positions radially outward from the second through hole 30h, compared to the fifth inner wall portions 91e and 93 e. Therefore, by matching the circumferential position of at least a part of the concave portions 33a, 33b, 34 with the circumferential position of the third inner wall portions 91c, 93c, it is possible to suppress the portion of the rotor core 30 located between the second through hole 30h and the radial direction of the first through holes 90a, 90b from becoming too thin. Accordingly, even when the recesses 33a, 33b, 34 recessed radially outward are provided at the inner edge of the second through hole 30h, the rigidity of the rotor core 30 can be suppressed from decreasing.

The portion of the other side (- θ side) of the recess 33a in the circumferential direction is arranged at the same position in the circumferential direction as the third inner wall portion 93c in the first through hole 90b located radially outward of the recess 33 a. The portion of the recess 33b on one circumferential side (+θ side) is arranged at the same position in the circumferential direction as the third inner wall portion 91c in the first through hole 90a located on the radially outer side of the recess 33 b. A part of the portion of the recess 34 on the circumferential side is arranged at the same position in the circumferential direction as the third inner wall portion 91c in the first through hole 90a located on the radially outer side of the recess 34. A part of the other side portion of the recess 34 in the circumferential direction is arranged at the same position in the circumferential direction as the third inner wall portion 93c in the first through hole 90b located radially outward of the recess 34. In the present embodiment, the circumferential center portion of the recess 34 and the protrusion 32 are disposed radially inward of the pair of first through holes 90a, 90b disposed circumferentially opposite to each other of the second connecting portion 92b and the second connecting portion 94 b.

The present utility model is not limited to the above-described embodiments, and other configurations and other methods may be adopted within the scope of the technical idea of the present utility model. The shape of the first through hole is not particularly limited as long as it is provided at a position overlapping with a virtual line extending in the radial direction passing through the circumferential centers between the circumferentially adjacent magnet holding parts when viewed in the axial direction, and is asymmetric with the virtual line interposed therebetween. When the inner wall of the first through hole has a shape having the first to sixth inner wall portions and the first to sixth connecting portions as viewed in the axial direction, each connecting portion may have any shape as long as it is a portion connecting the two inner wall portions to each other. Each connecting portion may be a point at which end portions of the two inner wall portions are connected to each other when viewed in the axial direction, for example. In the case where each of the connecting portions is arcuate when viewed in the axial direction, the radius of curvature in each of the connecting portions is not particularly limited. The inner wall portions may have any shape when viewed in the axial direction. Each inner wall portion may be linear or curved when viewed in the axial direction.

The number of the first through holes is not particularly limited as long as it is one or more. In the case where the plurality of first through holes are provided, the plurality of first through holes may all have the same shape or may all have different shapes. In the case where the plurality of first through holes include first through holes having different shapes, the first through holes having different shapes may be inverted in the circumferential direction as in the above embodiment, or may be inverted in the circumferential direction. The plurality of first through holes may not be arranged in rotational symmetry about the central axis.

A pair of second magnet holes may not be provided. Instead of a pair of second magnet holes, the rotor core may also have a third magnet hole located between the circumferences of the pair of first magnet holes each other. The third magnet hole may extend in a straight line along the circumferential direction, for example. The number of the magnet holding portions is not particularly limited as long as it is two or more.

The rotary electric machine to which the present utility model is applied is not limited to the motor, but may be a generator. The use of the rotary electric machine is not particularly limited. The rotating electric machine may be mounted on a device other than the vehicle. The application of the driving device to which the present utility model is applied is not particularly limited. The driving device may be mounted on a vehicle in a use other than the use for rotating the axle, or may be mounted on a device other than the vehicle. The posture when the rotary electric machine and the driving device are used is not particularly limited. The central axis of the rotating electric machine may be inclined with respect to a horizontal direction orthogonal to the vertical direction, or may extend in the vertical direction.

In addition, the present technology can employ the following structure.

(1) A rotor core portion, which is a rotor core portion of a rotor rotatable about a central axis, having: a plurality of magnet holding parts arranged in a circumferential direction, the plurality of magnet holding parts respectively having a pair of first magnet holes adjacent to each other in the circumferential direction; and a first through hole penetrating the rotor core in the axial direction, the first through hole having a portion located radially inward of the first magnet holes, the pair of first magnet holes extending in a direction that is circumferentially separated from each other as seen in the axial direction from the radially inward side toward the radially outward side, the first through hole being provided at a position overlapping an imaginary line as seen in the axial direction and in an asymmetric shape sandwiching the imaginary line, wherein the imaginary line passes through a circumferential center between circumferentially adjacent magnet holding parts and extends in the radial direction.

(2) In the rotor core according to (1), an inner wall of the first through hole has, when viewed in the axial direction: a first connecting portion located at the most radially outer side of an inner wall of the first through hole; a first inner wall portion connected to one side of the first connecting portion in the circumferential direction and extending radially inward from the first connecting portion; a second inner wall portion connected to the other circumferential side of the first connecting portion and extending radially inward from the first connecting portion; a second connecting portion connected to a radially inner end portion of the second inner wall portion; a third inner wall portion connected to the second inner wall portion via the second connection portion, and extending from the second connection portion in a direction approaching the first inner wall portion in the circumferential direction; a third connecting portion connected to an end portion of the third inner wall portion on a side opposite to a side connected to the second connecting portion; a fourth inner wall portion connected to the third inner wall portion via the third connecting portion; a fourth connecting portion connected to an end portion of the fourth inner wall portion on a side opposite to a side connected to the third connecting portion; a fifth inner wall portion connected to the fourth inner wall portion via the fourth connecting portion and located radially inward of the third inner wall portion; a fifth connecting portion connected to an end portion of the fifth inner wall portion on a side opposite to a side connected to the fourth connecting portion; a sixth connecting portion connected to a radially inner end portion of the first inner wall portion; and a sixth inner wall portion extending in a radial direction, connected to the fifth inner wall portion via the fifth connecting portion, and connected to the first inner wall portion via the sixth connecting portion.

(3) In the rotor core according to (2), the first connecting portion is provided at a position where at least a part thereof overlaps the virtual line when viewed in the axial direction, and the first inner wall portion and the second inner wall portion extend in directions that are circumferentially separated from each other as they are directed radially inward from the first connecting portion when viewed in the axial direction.

(4) In the rotor core according to (2) or (3), the first connecting portion, the second connecting portion, the fourth connecting portion, the fifth connecting portion, and the sixth connecting portion are formed in an arc shape recessed outward of the first through hole when viewed in the axial direction, and the third connecting portion is formed in an arc shape protruding inward of the first through hole when viewed in the axial direction.

(5) In the rotor core according to (4), the radius of curvature of the first connecting portion and the radius of curvature of the second connecting portion are identical to each other.

(6) In the rotor core according to (4) or (5), the radius of curvature of the fourth connecting portion, the radius of curvature of the fifth connecting portion, and the radius of curvature of the sixth connecting portion are the same as each other.

(7) In the rotor core of any one of (4) to (6), a radius of curvature of the third connecting portion is smaller than a radius of curvature of the fourth connecting portion, a radius of curvature of the fifth connecting portion, and a radius of curvature of the sixth connecting portion.

(8) In the rotor core according to any one of (4) to (7), the radius of curvature of the fourth connecting portion, the radius of curvature of the fifth connecting portion, and the radius of curvature of the sixth connecting portion are smaller than the radius of curvature of the first connecting portion and the radius of curvature of the second connecting portion.

(9) In the rotor core of any one of (2) to (8), the first inner wall portion is located radially inward of the first magnet hole of one of the circumferentially adjacent magnet holding portions, and extends in a direction in which the first magnet hole extends when viewed in the axial direction, and the fourth inner wall portion extends in a direction in which the first inner wall portion extends when viewed in the axial direction.

(10) In the rotor core according to (9), the second inner wall portion is located radially inward of the first magnet hole of the other one of the circumferentially adjacent magnet holding portions, and extends in a direction in which the first magnet hole extends when viewed in the axial direction.

(11) In the rotor core of any one of (2) to (10), the magnet holding portion has a pair of second magnet holes located radially outward of the pair of first magnet holes, the pair of second magnet holes extending in directions that are circumferentially separated from each other as seen in the axial direction from radially inward toward radially outward, the sixth inner wall portion extending along a first tangential line when seen in the axial direction, the first tangential line being tangential to a portion of the pair of first magnet holes that is closest to the other one of the pair of first magnet holes in the circumferential direction, the first tangential line extending along a second tangential line when seen in the axial direction, the second tangential line being tangential to a portion of the pair of second magnet holes that is closest to the other one of the pair of second magnet holes in the circumferential direction.

(12) In the rotor core according to any one of (2) to (11), the third inner wall portion is arranged along a first imaginary circle when viewed in the axial direction, the fifth inner wall portion is arranged along a second imaginary circle when viewed in the axial direction, and the first imaginary circle and the second imaginary circle are concentric circles.

(13) The rotor core according to any one of (2) to (12) includes a second through hole penetrating the rotor core in the axial direction, the center axis passes through the inside of the second through hole, a recess recessed radially outward is provided in an inner edge of the second through hole, and at least a part of the recess and the third inner wall portion are arranged at the same position in the circumferential direction.

(14) In the rotor core according to any one of (1) to (13), the first through holes are provided in plural at intervals in the circumferential direction, and when the number of the magnet holding portions is N, the plural first through holes are arranged symmetrically N/2 times around the central axis.

(15) A rotating electrical machine is provided with: a rotor having the rotor core of any one of (1) to (14); and a stator that is opposed to the rotor with a gap therebetween in a radial direction.

(16) A driving device is provided with: the rotary electric machine according to (15); and a gear mechanism connected to the rotating electric machine.

The structures described above in this specification can be appropriately combined within a range not contradicting each other.

Claims

1. A rotor core portion of a rotor rotatable about a central axis, comprising:

a plurality of magnet holding parts arranged in a circumferential direction, the plurality of magnet holding parts respectively having a pair of first magnet holes adjacent to each other in the circumferential direction; and

a first through-hole penetrating the rotor core in an axial direction, the first through-hole having a portion located radially inward of the first magnet hole,

the pair of first magnet holes extend in directions that are circumferentially separated from each other as viewed in the axial direction from the radially inner side toward the radially outer side,

the first through hole is provided at a position overlapping a virtual line extending in a radial direction through a circumferential center between the circumferentially adjacent magnet holding parts, and is in an asymmetric shape sandwiching the virtual line when viewed in the axial direction.

2. The rotor core as recited in claim 1, wherein,

the inner wall of the first through hole has, when viewed in the axial direction:

a first connecting portion located at the most radially outer side of an inner wall of the first through hole;

a first inner wall portion connected to one side of the first connecting portion in the circumferential direction and extending radially inward from the first connecting portion;

a second inner wall portion connected to the other circumferential side of the first connecting portion and extending radially inward from the first connecting portion;

a second connecting portion connected to a radially inner end portion of the second inner wall portion;

a third inner wall portion connected to the second inner wall portion via the second connection portion, and extending from the second connection portion in a direction approaching the first inner wall portion in the circumferential direction;

a third connecting portion connected to an end portion of the third inner wall portion on a side opposite to a side connected to the second connecting portion;

a fourth inner wall portion connected to the third inner wall portion via the third connecting portion;

a fourth connecting portion connected to an end portion of the fourth inner wall portion on a side opposite to a side connected to the third connecting portion;

A fifth inner wall portion connected to the fourth inner wall portion via the fourth connecting portion and located radially inward of the third inner wall portion;

a fifth connecting portion connected to an end portion of the fifth inner wall portion on a side opposite to a side connected to the fourth connecting portion;

a sixth connecting portion connected to a radially inner end portion of the first inner wall portion; and

and a sixth inner wall portion extending in a radial direction, connected to the fifth inner wall portion via the fifth connecting portion, and connected to the first inner wall portion via the sixth connecting portion.

3. A rotor core according to claim 2, wherein,

the first connecting portion is provided at a position where at least a part thereof overlaps the virtual line when viewed in the axial direction,

the first inner wall portion and the second inner wall portion extend in directions that are circumferentially separated from each other as seen in the axial direction from the first connecting portion toward the radially inner side.

4. A rotor core according to claim 2, wherein,

the first connecting portion, the second connecting portion, the fourth connecting portion, the fifth connecting portion, and the sixth connecting portion are formed in an arc shape recessed outward of the first through hole when viewed in the axial direction,

The third connecting portion has an arc shape protruding inward of the first through hole when viewed in the axial direction.

5. The rotor core as recited in claim 4, wherein,

the radius of curvature of the first connecting portion and the radius of curvature of the second connecting portion are identical to each other.

6. The rotor core as recited in claim 4, wherein,

the radius of curvature of the fourth connecting portion, the radius of curvature of the fifth connecting portion, and the radius of curvature of the sixth connecting portion are identical to each other.

7. The rotor core as recited in claim 4, wherein,

the curvature radius of the third connecting portion is smaller than the curvature radius of the fourth connecting portion, the curvature radius of the fifth connecting portion and the curvature radius of the sixth connecting portion.

8. The rotor core as recited in claim 4, wherein,

the curvature radius of the fourth connecting portion, the curvature radius of the fifth connecting portion and the curvature radius of the sixth connecting portion are smaller than those of the first connecting portion and the second connecting portion.

9. The rotor core as claimed in any one of claims 2 to 8, characterized in that,

the first inner wall portion is located radially inward of the first magnet hole of one of the circumferentially adjacent magnet holding portions and extends in a direction in which the first magnet hole extends when viewed in the axial direction,

The fourth inner wall portion extends in a direction in which the first inner wall portion extends when viewed in the axial direction.

10. The rotor core as recited in claim 9, wherein,

the second inner wall portion is located radially inward of the first magnet hole of the other one of the circumferentially adjacent magnet holding portions, and extends in a direction in which the first magnet hole extends when viewed in the axial direction.

11. The rotor core as claimed in any one of claims 2 to 8, characterized in that,

the magnet holding portion has a pair of second magnet holes located radially outward of the pair of first magnet holes,

the pair of second magnet holes extend in directions that are circumferentially separated from each other as viewed in the axial direction from the radially inner side toward the radially outer side,

the sixth inner wall portion extends along a first tangent line, as viewed in the axial direction, which is tangent to a portion of the pair of first magnet holes that is closest to the other first magnet hole in the circumferential direction,

the first tangent line extends along a second tangent line, as viewed in the axial direction, which is tangent to a portion of the pair of second magnet holes that is closest to the other second magnet hole in the circumferential direction.

12. The rotor core as claimed in any one of claims 2 to 8, characterized in that,

the third inner wall portion is arranged along the first imaginary circle when viewed in the axial direction,

the fifth inner wall portion is arranged along a second imaginary circle when viewed in the axial direction,

the first imaginary circle and the second imaginary circle are concentric circles.

13. The rotor core as claimed in any one of claims 2 to 8, characterized in that,

having a second through hole penetrating the rotor core in an axial direction,

the central axis passes through the inside of the second through hole,

a concave part which is concave towards the radial outside is arranged at the inner edge of the second through hole,

at least a part of the recess is arranged at the same position in the circumferential direction as the third inner wall portion.

14. The rotor core as claimed in any one of claims 1 to 8, characterized in that,

the first through holes are provided in plurality at intervals in the circumferential direction,

when the number of the magnet holding parts is N, the plurality of first through holes are arranged symmetrically N/2 times around the central axis.

15. An electric rotating machine, comprising:

a rotor having the rotor core of any one of claims 1 to 8; and

A stator that is opposed to the rotor with a gap therebetween in a radial direction.

16. A driving device is characterized by comprising:

the rotary electric machine of claim 15; and

and the gear mechanism is connected with the rotating motor.