CN116458032A - Rotor and rotating electrical machine - Google Patents

Abstract

The rotor includes: a rotor core (22) having a plurality of stacked core pieces (30) and a plurality of magnet accommodating holes (24) having a convex folded shape protruding radially inward; and a permanent magnet (23) embedded in the magnet accommodating hole of the rotor core. Each of the plurality of core pieces includes a first magnet through hole (31) having coupling portions (31 c, 61) for coupling the inner peripheral edge portions facing each other in the hole width direction at intermediate positions of the folded-back shape corresponding to the magnet accommodating hole, and a second magnet through hole (32) having no coupling portions (31 c, 61). The plurality of core pieces are identical in structure to one another. A plurality of core pieces are stacked so that the first magnet through hole and the second magnet through hole are mixed in one magnet housing hole of the rotor core.

Description

Rotor and rotating electrical machine

Citation of related application

The present application is based on Japanese patent application No. 2020-196160 and No. 2021-094750 to No. 4/6/2021, 11/26, respectively, the contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to a rotor and a rotating electrical machine of an embedded magnet type.

Background

Rotating electrical machines using a rotor of an embedded magnet type (IPM type) are well known. The embedded magnet type rotor is configured such that a permanent magnet is embedded in the rotor core, and a reluctance torque is obtained in an outer core portion located radially outward of the permanent magnet in addition to a magnet torque generated by the permanent magnet.

In such a rotor of the embedded magnet type, when the permanent magnet has a convex folded shape such as a V-shape or a U-shape that protrudes radially inward when viewed in the axial direction (for example, see patent document 1), the magnet surface of the permanent magnet that contacts the outer core portion and the outer core portion itself can be increased. That is, a higher torque of the rotating electrical machine can be expected.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2018-85779

Disclosure of Invention

Because of the relationship in which the rotor core has magnet accommodating holes for accommodating permanent magnets, it is difficult to set the position, shape, and the like of the connecting portion that connects the outer core portion and the main body side portion of the rotor core. This is because the connecting portion is also a portion where magnetic flux leakage occurs. Therefore, if the connecting portion is narrowed, the connecting portion supporting the outer core portion is structurally weakened, resulting in a decrease in centrifugal force strength of the outer core portion, or the like. The larger the outer core portion is, the more remarkable the torque is to be increased. The present inventors studied whether or not such a technical problem can be solved by simple countermeasure. The purpose of the present disclosure is to provide a rotor and a rotating electrical machine that can expect an increase in centrifugal force strength through simple handling.

The rotor of the first aspect of the present disclosure includes: a rotor core having a plurality of stacked core pieces and a plurality of magnet accommodating holes each having a convex folded shape protruding radially inward; and a permanent magnet buried in the magnet receiving hole of the rotor core. Each of the plurality of core pieces includes a first magnet through hole having a connecting portion and a second magnet through hole having no connecting portion, and the connecting portion connects inner peripheral portions facing each other in a hole width direction at a halfway position of a folded shape corresponding to the magnet housing hole. The plurality of core pieces are identical in structure to each other. The plurality of core pieces are stacked so that the first magnet through hole and the second magnet through hole are mixed in one of the magnet accommodating holes of the rotor core.

The rotating electrical machine of the second aspect of the present disclosure includes: a rotor core having a plurality of stacked core pieces and a plurality of magnet accommodating holes each having a convex folded shape protruding radially inward; a permanent magnet embedded in a magnet accommodating hole of the rotor core; and a stator that applies a rotating magnetic field to the rotor. Each of the plurality of core pieces includes a first magnet through hole having a connecting portion and a second magnet through hole having no connecting portion, and the connecting portion connects inner peripheral portions facing each other in a hole width direction at a halfway position of a folded shape corresponding to the magnet housing hole. The plurality of core pieces are identical in structure to each other. The plurality of core pieces are stacked so that the first magnet through hole and the second magnet through hole are mixed in one of the magnet accommodating holes of the rotor core.

According to the rotor and the rotating electrical machine, the first magnet through hole having the coupling portion at the halfway position of the folded shape corresponding to the magnet accommodating hole of the rotor core and the second magnet through hole having no coupling portion are provided in a single core piece in a mixed manner. When the rotor core is laminated, the plurality of core pieces have the same structure, and the rotor core is laminated such that the first magnet through hole and the second magnet through hole are mixed in one magnet housing hole. That is, the outer core portion of the rotor core portion located radially outward of the permanent magnets is formed as follows: in addition to the coupling portion of two portions of the embedded magnet type rotor, which is inevitably included in the original structure of the magnet housing hole, on the outer side than the radially outer end portion of the embedded magnet type rotor, the coupling portion of the first magnet through hole is added, and the embedded magnet type rotor is supported by the common portion of the rotor core portion at three or more portions. Therefore, the centrifugal force strength of the outer core portion can be improved. Moreover, the rotor and the rotary electric machine of the present disclosure can be realized by a simple countermeasure in which only one type of core piece is prepared.

Drawings

The above objects, and other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. The drawings are as follows.

Fig. 1 is a structural diagram of a rotating electrical machine having a rotor of an embedded magnet type in one embodiment.

Fig. 2 is a top view of the rotor of fig. 1.

Fig. 3 is a perspective view of the rotor of fig. 1.

Fig. 4 (a) and 4 (b) are plan views of core pieces for the rotor of fig. 1.

Fig. 5 is an explanatory diagram for explaining characteristics of the rotor of fig. 1.

Fig. 6 is an explanatory diagram for explaining characteristics of the rotor of fig. 1.

Fig. 7 is a perspective view of a rotor in a modification.

Fig. 8 is a perspective view of a rotor in a modification.

Fig. 9 is a perspective view of a rotor in a modification.

Fig. 10 is a perspective view of a rotor in a modification.

Fig. 11 is a plan view of a rotor in a modification.

Fig. 12 is a cross-sectional view taken along line XII-XII in fig. 11.

Fig. 13 is a sectional view taken along line XIII-XIII in fig. 11.

Fig. 14 (a) and 14 (b) are plan views of core pieces for the rotor of fig. 11.

Fig. 15 is a plan view of a rotor in a modification.

Fig. 16 is a cross-sectional view taken along line XVI-XVI of fig. 15.

Fig. 17 is a cross-sectional view of a rotor in a modification.

Fig. 18 is a plan view of a rotor in a modification.

Fig. 19 is a plan view of a core sheet in a modification.

Detailed Description

An embodiment of the rotor and the rotating electrical machine will be described below. The description "at least one of a and B" in this specification is understood to mean "a alone, or B alone, or both a and B".

The rotating electric machine M of the present embodiment shown in fig. 1 is constituted by a brushless motor of a buried magnet type. The rotating electrical machine M includes: a substantially annular stator 10; and a substantially cylindrical rotor 20 rotatably disposed in a space radially inside the stator 10.

The stator 10 includes a generally annular stator core 11. The stator core 11 is made of a magnetic metal material, for example, a plurality of electromagnetic steel plates stacked. In the present embodiment, the stator core 11 has twelve pole teeth 12 extending radially inward and arranged at equal intervals in the circumferential direction. The teeth 12 are identical in shape to each other. The tip end portion, i.e., the radially inner end portion of the pole tooth 12 is substantially T-shaped, and the tip end surface 12a is arcuate along the outer peripheral surface of the rotor 20. The windings 13 are wound around the twelve teeth 12 in concentrated winding. That is, the number of poles of the stator 10 is "12". The windings 13 are three-phase wires, and as shown in fig. 1, function as U-phase, V-phase, and W-phase, respectively. When power is supplied to the winding 13, a rotating magnetic field for driving the rotor 20 to rotate is generated in the stator 10. In the stator 10 as described above, the outer peripheral surface of the stator core 11 is fixed with respect to the inner peripheral surface of the housing 14.

In the present embodiment, the rotor 20 includes: a rotation shaft 21; a substantially cylindrical rotor core 22 having a rotary shaft 21 inserted into a center portion thereof; and eight permanent magnets 23 in the form of being buried inside the rotor core 22. That is, the number of poles of the rotor 20 is "8". The rotor 20 is rotatably disposed with respect to the stator 10 by supporting a rotary shaft 21 on a bearing, not shown, provided in the housing 14.

As shown in fig. 2, the rotor core 22 has a magnet accommodating hole 24 for accommodating the permanent magnet 23. In the present embodiment, eight magnet housing holes 24 are provided at equal intervals along the circumferential direction of the rotor core 22. Each of the magnet housing holes 24 has a convex substantially V-shaped folded shape protruding radially inward, that is, a shape in which radially inner end portions of a pair of straight portions 24a are connected to each other by a bent portion 24 b. The radially outer end 24c of the linear portion 24a of the magnet housing hole 24 is located near the outer peripheral surface 22a of the rotor core 22. The bent portion 24b is located near the shaft insertion hole 22b of the center portion of the rotor core 22 into which the rotary shaft 21 is inserted.

The magnet housing hole 24 is set such that the hole width of the pair of straight portions 24a (corresponding to the thickness Wm of the straight portion 23a of the permanent magnet 23) is constant, and the hole width of the curved portion 24b (corresponding to the thickness Wm1 of the curved portion 23b of the permanent magnet 23) is gradually narrower than the straight portion 24 a. The magnet housing hole 24 is provided in the entire axial direction of the rotor core 22. The magnet housing holes 24 have substantially the same structure, but there are two types of magnet housing holes 24a of the first embodiment and magnet housing holes 24 β of the second embodiment (details will be described later) that are different in minute points.

As shown in fig. 3, the rotor core 22 is configured by stacking a plurality of core pieces 30 made of electromagnetic steel plates along the axis L1. For each of the core pieces 30, the core pieces 30 having the same structure as shown in fig. 4 (a) are used. The core piece 30 shown in fig. 4 (b) is different in shape at first glance, but is actually disposed at a second position where the magnet accommodating hole 24 is rotated by one amount, in other words, by one magnetic pole, with respect to the first position shown in fig. 4 (a). In order to form the two types of magnet housing holes 24 of the rotor core 22, two types of magnet through holes 31 and 32 are formed in the core piece 30 in a mixed manner.

The first magnet through-hole 31 and the second magnet through-hole 32 are each formed in a convex substantially V-shaped folded shape that protrudes substantially inward in the radial direction, that is, in a shape in which radially inner end portions of the pair of straight portions 31a, 32a are connected to each other by the bent portions 31b, 32 b. The first magnet through-hole 31 and the second magnet through-hole 32 are formed in the following shapes at different portions from each other: the first magnet through hole 31 has a connecting portion 31c at the bent portion 31b, and the second magnet through hole 32 has no connecting portion such as the connecting portion 31c at the bent portion 32 b. The connecting portion 31c extends in the hole width direction of the first magnet through hole 31 and connects inner peripheral portions facing each other in the hole width direction. The width Wb of the connecting portion 31c is set to be equal to or smaller than the plate thickness t (see fig. 3) of one of the core pieces 30. The side edge 31d of the connecting portion 31c has a uniform curved shape having a narrower width as it approaches the central portion of the connecting portion 31c in the extending direction. As an example, the curved shape of the side edge 31d is set to a radius of curvature of approximately 1/2 of the length of the connecting portion 31c in the extending direction. The first and second through holes 31 and 32 are alternately arranged at 45 ° intervals in the circumferential direction in each core piece 30.

In the process of stacking the core pieces 30 to form the rotor core 22, in the present embodiment, the core pieces 30 disposed at the first position shown in fig. 4 (a) and the core pieces 30 disposed at the second position shown in fig. 4 (b) rotated by 45 ° are alternately stacked in units of one piece. That is, when the rotor core 22 is configured, as shown in fig. 2, the magnet housing holes 24 α of the first embodiment are configured such that the first magnet through holes 31 having the connecting portions 31c at the bent portions 31b and the second magnet through holes 32 having no connecting portions at the bent portions 32b are sequentially alternated from the upper layer toward the lower layer, and the magnet housing holes 24 β of the second embodiment are configured such that the second magnet through holes 32 having no connecting portions at the bent portions 32b and the first magnet through holes 31 having the connecting portions 31c at the bent portions 32b are sequentially alternated. The first magnet through-hole 31 and the second magnet through-hole 32 of the first magnet housing hole 24a and the second magnet housing hole 24 β are arranged in reverse order to each other.

That is, in the case of the rotor core 22, the outer core portion 25, which will be described later, is supported by the common portion 22x of the rotor core 22 at three positions, that is, the connecting portion 22d at two positions that are located further outside than the radial outer end portions 24c of the pair of straight portions 24a of the magnet housing hole 24 and the connecting portion 31c that separates the first magnet through holes 31 provided in the one-piece core piece 30, at the inner side of the V-shaped folded shape of the permanent magnet 23 provided in the magnet housing hole 24. Therefore, in addition to the two-part connecting portion 22d that is necessarily included in the structure of the magnet housing hole 24, the connecting portion 31c located in the bent portion 24b also serves as a newly added third part, supporting the outer core portion 25, and thereby improving the centrifugal force strength of the outer core portion 25.

The connecting portions 22d and 31c are provided at three positions for one outer core portion 25, but the connecting portions 22d and 31c at three positions are arranged uniformly around the outer core portion 25, contributing to stable support of the outer core portion 25. Further, by setting the thickness t of one of the core pieces 30 to be equal to or less than the thickness t of each of the three connecting portions 22d and 31c, it is possible to sufficiently reduce the magnetic flux leakage that may occur. Further, at the radially outer end 24c of the magnet housing hole 24, there are provided protruding portions 22e (japanese: forcing portions) which protrude in a tapered shape at the inner corners of the V-shaped folded-back shape, respectively. In other words, the radially outer end 24c of the magnet housing hole 24 is narrowed, and the length Lb of the connecting portion 22d on the outer side thereof is smaller than the hole width of the linear portion 24a of the magnet housing hole 24 (corresponding to the thickness Wm of the linear portion 23a of the permanent magnet 23). This can also increase the centrifugal force strength of the outer core portions 25.

In the present embodiment, in which the number of core pieces 30 is an odd number, as shown in fig. 3, the opening shapes of the magnet accommodating holes 24 formed in the two axial end faces 22c of the rotor core 22 near the upper surface and near the lower surface are the same. When the number of core pieces 30 is an even number, the opening shape of the magnet housing hole 24 formed in the axial end face 22c of the rotor core 22 may be selected to be the shape of one of the magnet through holes 31 and 32. The permanent magnets 23 are provided in the respective magnet housing holes 24 configured as described above in a buried state.

The permanent magnet 23 is a bonded magnet formed by molding and hardening a magnet material obtained by mixing a magnet powder and a resin in the present embodiment. That is, the permanent magnet 23 is configured by setting the magnet accommodating hole 24 of the rotor core 22 as a molding die, filling the magnet material before curing into the magnet accommodating hole 24 without gaps by injection molding, and curing the magnet material in the magnet accommodating hole 24 after filling. Therefore, the hole shape of the magnet housing hole 24 becomes the outer shape of the permanent magnet 23. In this case, the magnet material is wound around the magnet housing holes 24 between the connecting portions 31c provided in each of the core pieces 30. As the magnet powder used for the permanent magnet 23 of the present embodiment, for example, a samarium iron nitrogen (SmFeN) magnet is used, but other rare earth magnets may be used.

As shown in fig. 2, the permanent magnet 23 is formed in a convex substantially V-shaped folded shape that bulges radially inward when viewed in the axial direction, that is, in a shape in which radially inner end portions of a pair of straight portions 23a are connected to each other by a bent portion 23 b. The radially outer end 23c of the straight portion 23a is located near the outer peripheral surface 22a of the rotor core 22. The permanent magnet 23 is set so that the thickness Wm of the pair of straight portions 23a is constant, and the thickness Wm1 of the curved portion 23b is gradually narrower than the thickness Wm of the straight portion 23 a. The permanent magnet 23 is formed directly with respect to the magnet accommodating hole 24, and thus is formed in a shape corresponding to the magnet accommodating hole 24. The permanent magnets 23 are line-symmetrical with respect to a circumferential center line Ls itself passing through the axial center O1 of the rotor 20, and are close to a magnetic pole boundary line Ld passing through the axial center O1 of the rotor 20 between adjacent permanent magnets 23. The angle between adjacent magnetic pole boundary lines Ld, that is, the magnetic pole opening angle θm of the rotor magnetic pole portion 26 including the permanent magnet 23 is an electrical angle of 180 °.

Here, the magnetic pole pitch Lp is set between the intersection point of the extension line of the inner side surface of each linear portion 23a of the V-shaped permanent magnet 23 and the outer circumferential surface 22a of the rotor core 22, and the distance from the outer circumferential surface 22a of the rotor core 22 to the inner side surface of the curved portion 23b on the circumferential center line Ls of the permanent magnet 23 is set to the embedding depth Lm. The permanent magnet 23 of the present embodiment is set to a deep folded shape in which the bent portion 23b of the permanent magnet is close to the center portion of the rotor core 22, such that the embedded depth Lm is larger than the magnetic pole pitch Lp. That is, the magnet surface 23d of the permanent magnet 23 of the present embodiment, which is formed by the inner side surfaces of the straight portions 23a and the curved portions 23b, is set to be larger than a magnet surface (not shown) of a well-known surface magnet type. The folded shape of the permanent magnet 23 is an example, and can be changed to a substantially U-shaped folded shape having a shallow embedding depth Lm or a large bent portion 23b, as appropriate.

As shown in fig. 3, the permanent magnets 23 are provided in the entire axial direction of the rotor core 22, and a part thereof protrudes from both axial end surfaces 22c of the rotor core 22. The permanent magnet 23 has an embedded magnet portion 23m located in the magnet accommodating hole 24 and protruding portions 23x protruding from the axial both end surfaces 22c of the rotor core 22, respectively. The formation of the protruding portion 23x can be easily achieved by providing a recess for forming the protruding portion 23x in a not-shown molding die for closing the magnet housing hole 24 that is opened in the axial end face 22c of the rotor core 22, for example. The protruding portion 23x is integrally provided continuously with the embedded magnet portion 23m of the permanent magnet 23 located in the magnet accommodating hole 24 of the rotor core 22.

The permanent magnets 23 provided in the magnet accommodating holes 24 of the rotor core 22 so as to be substantially buried are magnetized from the outside of the rotor core 22 by a magnetization device, not shown, after the magnet material is cured, so as to function as original magnets. In this case, each permanent magnet 23 is magnetized in the thickness direction thereof. As shown in fig. 1, in the present embodiment, the permanent magnets 23 are provided with eight magnets in the circumferential direction of the rotor core 22, and are magnetized so that polarities are alternately different in the circumferential direction.

The portion of the rotor core 22 located inside the V-shaped fold-back shape of the permanent magnet 23 and radially outside the permanent magnet 23 functions as an outer core portion 25 for facing the stator 10 to obtain reluctance torque. The outer core portion 25 has a substantially triangular shape with one apex directed toward the center of the rotor 20 when viewed in the axial direction. In the present embodiment, the rotor 20 includes the permanent magnets 23 and the outer core portions 25 surrounded by the inner sides of the V-shapes of the permanent magnets 23, and is configured as an 8-pole rotor magnetic pole portion 26. As shown in fig. 1, each of the rotor magnetic pole portions 26 alternately functions as an N pole and an S pole in the circumferential direction. In the rotor 20 having such a rotor magnetic pole portion 26, the magnet torque and the reluctance torque can be appropriately obtained.

The operation of the rotor 20 of the rotating electrical machine M of the present embodiment will be described.

The rotor core 22 constituting the rotor 20 according to the present embodiment is formed by stacking a plurality of core pieces 30 in which the first magnet through holes 31 having the connecting portions 31c and the second magnet through holes 32 having no connecting portions are alternately mixed in the circumferential direction as shown in fig. 4. In this case, 1 kind of core sheet 30 is prepared. Then, as shown in fig. 3, a predetermined number of core pieces 30 are stacked so that each of the core pieces arranged at the first position and each of the core pieces arranged at the second position rotated by 45 ° are alternately stacked to construct the rotor core 22. Then, the permanent magnets 23 are directly formed in the magnet housing holes 24, specifically, the first-type magnet housing holes 24 a and the second-type magnet housing holes 24 β having substantially the same structure in which only the first magnet through holes 31 and the second magnet through holes 32 are different in order, and then the permanent magnets 23 are magnetized to construct the rotor 20.

As shown in fig. 2 and 3, the outer core portion 25 located radially outward of the permanent magnets 23 is supported by the common portion 22x of the rotor core 22 at three locations, that is, the connecting portion 22d located at two locations outward of the radially outer end 24c of the magnet housing hole 24 and the connecting portion 31c located at the radially inner bent portion 24b and provided in each of the core pieces 30, in the rotor core 22. That is, the outer core portion 25 of the rotor core portion 22 according to the present embodiment is supported as follows: in addition to the two-part coupling portion 22d that is necessarily included in the structure of the magnet housing hole 24, the coupling portion 31c also serves as a support for the newly added third part, and therefore, the centrifugal force strength of the outer core portion 25 is improved.

Fig. 5 shows the comparison results of the present embodiment (this embodiment in the figure) and comparative examples 1 and 2 (comparative examples 1 and 2 in the figure) for evaluating the centrifugal force strength of the outer core portions 25. In comparative example 1, the buried depth Lm (see fig. 2) of the permanent magnet 23 was a shallow folded shape of about half the radius of the rotor core 22. In comparative example 2, the permanent magnet 23 is formed in a deep folded shape as in the present embodiment in which the permanent magnet 23 is located near the center of the rotor core 22, but the permanent magnet is formed to have a magnet accommodating hole 24 having no connecting portion 31c at the bent portion 24 b. In comparative example 2, the permanent magnet 23 had no protruding portion 23x (see fig. 3), and the magnet housing hole 24 had no protruding portion 22e (see fig. 2). In addition, this is a comparison between comparative example 2 and the present embodiment, in which the stress of comparative example 1, which involves the connecting portion 22d at two points for supporting the outer core portion 25, is "1". As comparative example 2, since the permanent magnet 23 is formed in a deep folded shape as compared with comparative example 1, the magnet surface 23d of the permanent magnet 23 and the outer core portion 25 themselves are correspondingly large, and thus a high torque can be expected, but the weight of the outer core portion 25 is correspondingly large, and the stress to the connecting portion 22d is larger than "1". That is, this means that the centrifugal force strength of the outer core portions 25 is reduced.

In contrast, in the present embodiment, since the outer core portion 25 is supported by three portions of the connecting portion 31c in addition to the two-portion connecting portion 22d, the stress to the connecting portion 22d becomes sufficiently smaller than "1". That is, the centrifugal force strength of the outer core portion 25 is improved.

Here, two kinds of core pieces 30, that is, a core piece 30 having only the first magnet through-holes 31 having the connecting portions 31c and a core piece 30 having only the second magnet through-holes 32 having no connecting portions, are prepared, and even if the core pieces 30 having different kinds are alternately stacked, the centrifugal force strength of the outer core portion 25 can be improved in the same manner as described above. However, two kinds of core pieces 30 have to be prepared, which may be complicated in manufacturing, management, and the like.

In contrast, in the present embodiment, the first magnet through-hole 31 having the connecting portion 31c and the second magnet through-hole 32 having no connecting portion are provided in a single core piece 30 in a mixed manner, and the core piece 30 is stacked so that the first magnet through-hole 31 and the second magnet through-hole 32 are mixed in one magnet housing hole 24. In the present embodiment, the first magnet through-holes 31 and the second magnet through-holes 32 are alternately mixed for each core piece 30. That is, in the present embodiment, it is possible to prepare only one type of core sheet 30 for simple handling.

Fig. 6 shows the comparison results of the torque/magnet volume ratio of the present embodiment (in the figure, this embodiment) with comparative examples 1 and 2 (in the figure, comparative examples 1 and 2). As described above, the permanent magnet 23 of comparative example 2 has a deep folded shape with respect to comparative example 1, and therefore the magnet surface 23d of the permanent magnet 23 and the outer core portion 25 themselves are strained greatly to have high torque, and the torque/magnet volume ratio is made larger than "1".

On the other hand, in the present embodiment, the outer core portion 25 is supported by three portions in which the connecting portion 31c is added in addition to the two-portion connecting portion 22 d. The connecting portions 22d and 31c are also portions where magnetic flux leakage of the permanent magnet 23 occurs, and there is a possibility that the newly added connecting portion 31c may cause a decrease in effective magnetic flux and a decrease in torque/magnet volume ratio. In the present embodiment, as a countermeasure therefor, a protruding portion 23x is provided that protrudes a part of the permanent magnet 23 from the axial end face 22c of the rotor core 22. Since the magnetic flux leakage occurs at the axial end face 22c of the rotor core 22 in the protruding portion 23x, the magnetic flux leakage of the embedded magnet portion 23m of the important permanent magnet 23, that is, the effective magnetic flux can be increased, and the torque can be increased. Further, focusing on the fact that the magnetic flux leakage is small at the bent portion 23b of the permanent magnet 23, the volume of the permanent magnet 23 can be reduced as much as possible by setting the thickness Wm1 of the bent portion 23b, and the torque/magnet volume ratio can be improved. Thus, in the present embodiment, although the magnetic flux leakage in this portion increases due to the increase of the coupling portion 31c, the torque/magnet volume ratio equivalent to that of comparative example 2 without the coupling portion can be obtained.

However, even if the permanent magnet 23 is not provided with the protruding portion 23x, and even if the thickness of the bent portion 23b is not made thin, the torque/magnet volume ratio is not so reduced but is larger than "1" (not shown), so that when an expensive magnet material or the like is used for the permanent magnet 23, it is sufficient to determine whether or not the protruding portion 23x is formed on the permanent magnet 23 and whether or not the thickness of the bent portion 23b is adjusted, in consideration of the magnet cost.

Effects of the present embodiment will be described.

(1) The plurality of core pieces 30 are identical in structure to one another. In the one-piece core piece 30, the first magnet through holes 31 having the connecting portions 31c at the bent portions 24b in the present embodiment and the second magnet through holes 32 having no connecting portions are alternately mixed in the circumferential direction at the halfway positions of the folded shapes corresponding to the magnet accommodating holes 24 of the rotor core 22. The plurality of core pieces 30 are stacked so that the first magnet through-hole 31 and the second magnet through-hole 32 are mixed in the single magnet housing hole 24. Specifically, the core sheets 30 are stacked so that every other first position and the second position rotated 45 ° are alternately performed. Namely, the following mode is adopted: the outer core portion 25 of the rotor core portion 22 located radially outward of the permanent magnets 23 is supported by the common portion 22x of the rotor core portion 22 as a newly added third portion of the connecting portion 31c of the first magnet through hole 31, in addition to the connecting portion 22d of the two portions of the embedded magnet type rotor 20 that are necessarily included in the original structure of the magnet housing hole 24 and are located radially outward of the radially outer end portion 24c thereof. Therefore, the centrifugal force strength of the outer core portions 25 can be improved. Moreover, the rotor and the rotary electric machine of the present disclosure can be realized by a simple countermeasure in which only one type of core piece 30 is prepared.

(2) In each of the plurality of core pieces 30, the first magnet through holes 31 and the second magnet through holes 32 are alternately arranged in the circumferential direction. Therefore, the rotor and the rotary electric machine of the present disclosure can be realized in a simple lamination manner in which the core pieces 30 are arranged one by one at any one of the first position and the second position in which the magnet accommodating hole 24 is rotated one amount from the first position. The core pieces 30 are arranged at the first position or the second position every other piece. Therefore, the coupling portions 31c of the first magnet through holes 31 are arranged so as not to overlap each other every other one core piece 30, and therefore, the magnetic flux leakage at the coupling portions 31c can be reduced as much as possible.

(3) The connecting portion 31c provided in the first magnet through hole 31 is located at the bent portion 31b of the folded shape of the first magnet through hole 31 itself, and is disposed around the outer core portion 25 in a balanced manner in terms of the positional relationship with the connecting portions 22d of the two portions. Accordingly, the rotor and the rotary motor of the present disclosure can contribute to stable support of the outer core portion 25.

(4) Since the width Wb of the connecting portion 31c itself provided in the first magnet through hole 31 is set to be not more than the plate thickness t of the core piece 30, the magnetic flux leakage at the connecting portion 31c can be reduced as much as possible.

(5) The connecting portion 31c provided in the first magnet through hole 31 has a uniform curved shape having a narrower width as the side edge portion 31d thereof approaches the central portion in the extending direction thereof. Therefore, the rigidity can be improved by widening at the end portion while reducing the magnetic flux leakage at the coupling portion 31c as much as possible. In addition, by forming the side edge portion 31d in a curved shape, stress concentration to the connecting portion 31c can be reduced.

(6) Since the rotor core 22 is narrowed by providing the protruding portion 22e at one corner of the radially outer end 24c of the magnet housing hole 24, and the connecting portion 22d outside the radially outer end 24c can be shortened, the centrifugal force strength of the outer core portion 25 can be improved.

(7) The permanent magnet 23 has its own axial end portion as a protruding portion 23x and protrudes from the axial end face 22c of the rotor core 22. Therefore, magnetic flux leakage at the axial end face 22c of the rotor core 22 mainly occurs in the protruding portion 23x thereof. That is, since the leakage of magnetic flux of the embedded magnet portion 23m of the important permanent magnet 23 can be reduced, the effective magnetic flux can be increased, and a high torque can be achieved.

(8) The permanent magnet 23 has a bent portion 23b in a folded shape, and the thickness Wm1 of the bent portion 23b is smaller than the thickness Wm of the straight portion 24 a. That is, focusing on the fact that the magnetic flux leakage is small at the curved portion 23b of the permanent magnet 23, the volume of the permanent magnet 23 can be reduced as much as possible by making the curved portion 23b thinner than the straight portion 24a, and the torque/magnet volume ratio can be improved.

The present embodiment can be modified and implemented as follows. The present embodiment and the following modifications can be combined and implemented within a range that is not technically contradictory.

The magnet accommodating hole 24 and the structure around the magnet accommodating hole 24 may be changed as appropriate.

As shown in fig. 7, for example, a protruding portion 22f protruding in a tapered shape may be provided at the radially outer end 24c of the magnet housing hole 24 at the outer corner of the V-shaped folded shape. That is, the protruding portion 22f may be provided at a corner portion on the opposite side of the protruding portion 22 e. In fig. 7, the protruding portion 22f may be provided only on the side of the magnet housing hole 24 β of the second embodiment, and the hole shape of the radially outer end 24c of the magnet housing hole 24 α of the first embodiment may be rectangular without the protruding portion 22f. That is, the protruding portion 22e or the protruding portion 22f may be provided in all or only a part of the plurality of magnet housing holes 24 provided in the circumferential direction.

As shown in fig. 8 and 9, for example, the hole width (corresponding to the thickness Wm2 of the permanent magnet 23) on the side of the magnet accommodating hole 24 β of the second embodiment may be made small. As shown in fig. 8, for example, the linear portion 24a of the magnet housing hole 24 β of the second embodiment may be spaced apart from the magnetic pole boundary line Ld as the curved portion 24b is directed. In this case, the straight line portion 24a is inclined with respect to the magnetic pole boundary line Ld. As shown in fig. 9, for example, the linear portion 24a of the magnet housing hole 24 β of the second embodiment may be uniformly distant from the magnetic pole boundary line Ld in a range from the radially outer end portion 24c to the curved portion 24 b. In this case, the straight line portion 24a is parallel to the magnetic pole boundary line Ld. The above also applies to the magnet housing hole 24a side of the first embodiment.

As shown in fig. 10, for example, the protruding portion 23x of the permanent magnet 23 may be omitted. In this case, the end portions of the permanent magnets 23 are coplanar with the axial end face 22c of the rotor core 22. As shown in fig. 10, for example, the hole width of the curved portion 24b of the magnet housing hole 24 (corresponding to the thickness Wm of the permanent magnet 23) may be set to be the same as the width of the linear portion 24 a.

The core pieces 30 are alternately arranged at the first position and the second position rotated 45 ° every other piece, but may be alternately arranged at the first position and the second position in a plurality of pieces. In this case, the number of pieces may be the same, or the number of pieces may be different.

The first magnet through holes 31 and the second magnet through holes 32 are alternately arranged in the circumferential direction of the core piece 30, that is, every other one of the first magnet through holes 31 and the second magnet through holes 32 is arranged, but any one of the first magnet through holes 31 and the second magnet through holes 32 may be arranged every other two or more.

The number of the connecting portions 31c of the first magnet through-holes 31 is one, but two or more may be provided. In this case, the coupling portion 22d of two parts necessarily included in the structure of the magnet accommodating hole 24 of the rotor core 22 is added, and the support portions of the outer core portion 25 are four or more in total. In addition, the bent portion 24b is provided as a halfway position of the folded shape of the magnet housing hole 24 with respect to the arrangement position of the coupling portion such as the coupling portion 31c, and the coupling portion 31c is provided at the bent portion 31b of the first magnet through hole 31 at this time, but may be provided at the straight portion 31a or the like in addition to the bent portion 31b, for example, in the above embodiment. In the above-described embodiment, the connecting portion 31c and other connecting portions are formed in such a shape that the connecting portion 31c extends in the hole width direction of the first magnet through hole 31, in this case, in a direction orthogonal to the inner peripheral edge portion of the first magnet through hole 31, and further, in the radial direction, but may be formed in a shape extending in a direction inclined with respect to the hole width direction, or in a direction extending in a direction other than the radial direction, for example.

The protruding portions 22e and 22f provided at the radially outer end 24c of the magnet housing hole 24 are formed in a tapered shape, but the protruding shape may be changed to a rectangular shape, a curved shape, or the like as appropriate. In addition to the above, the protruding portions 22e and 22f may be omitted, and the hole shape of the radially outer end 24c of the magnet housing hole 24 may be rectangular as shown in fig. 7 and the like.

The permanent magnet 23 is formed by injection molding a magnet material into the magnet accommodating hole 24 of the rotor core 22, but the permanent magnet 23 may be manufactured in advance and inserted into the magnet accommodating hole 24 of the rotor core 22 to be fixed.

The number of poles of the rotor 20, that is, the number of the permanent magnets 23 and the magnet accommodating holes 24 may be appropriately changed. The number of poles of the stator 10 may be changed as appropriate.

In addition to the above, the structure of rotating electric machine M may be changed as appropriate.

Fig. 11 to 18 show an example of a structure in which the concave-convex portion is provided on the inner surface of the magnet housing hole 24 in the above embodiment.

As shown in fig. 11, the inner surface of the magnet housing hole 24 that is in contact with the permanent magnet 23 includes an inner side surface 41 and an outer side surface 42. The inner side surface 41 is a side surface constituting the outer core portion 25, and is a surface that contacts the inner side of the V-shaped turn-back shape of the permanent magnet 23. The outer side surface 42 is a side surface opposite to the inner side surface 41 in the hole width direction. The hole width direction of the magnet accommodating hole 24 is a direction orthogonal to the extending direction of the magnet accommodating hole 24 when viewed in the axial direction. The extending direction of the magnet accommodating hole 24 is a direction along a substantially V-shaped folded shape when the magnet accommodating hole 24 is viewed from the axial direction. The inner side surface 41 and the outer side surface 42 are each a surface of a folded shape along the magnet housing hole 24 when viewed in the axial direction.

The inner side surface 41 has a first concave-convex portion (concave-convex portion) 43. The outer side surface 42 has second concave-convex portions (concave-convex portions) 44. The first concave-convex portion 43 is provided on the inner side surface 41 of the curved portion 24 b. The second concave-convex portion 44 is provided on the outer side surface 42 of the bent portion 24 b. Further, a third concave-convex portion (concave-convex portion) 45 is provided on the inner surface of the magnet housing hole 24 at a portion corresponding to the radially outer end portion 24c of the straight portion 24 a. In this example, the inner surface of the magnet housing hole 24 has non-concave-convex portions 46 that are portions where the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are not formed. The first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are partially formed in the extending direction of the magnet housing hole 24, and the non-concave-convex portion 46 is formed at other portions in the extending direction of the magnet housing hole 24.

The same structure as shown in fig. 14 (a) is used for each core piece 30 constituting the rotor core 22. This allows the core pieces 30 to be managed as the same member. The core piece 30 shown in fig. 14 (b) is different from the core piece 30 shown in fig. 14 (a) in shape at first glance, but is actually disposed at a second position where the magnet accommodating hole 24 is rotated by one amount, in other words, by 45 ° with respect to the first position shown in fig. 14 (a).

In the process of stacking the core pieces 30 to construct the rotor core 22, in this example, the core pieces arranged at the first position shown in fig. 14 (a) and the core pieces arranged at the second position shown in fig. 14 (b) rotated by 45 ° are alternately stacked in units of one piece. Thus, the first magnet through holes 31 and the second magnet through holes 32 are alternately overlapped in the axial direction. Each of the magnet accommodating holes 24 is constituted by a first magnet through hole 31 and a second magnet through hole 32 that overlap in the axial direction.

The first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are formed on the inner surface of the magnet housing hole 24 by the difference between the position of the peripheral edge portion of the first through hole 31 for the magnet and the position of the peripheral edge portion of the second through hole 32 for the magnet.

As shown in fig. 11 and 12, the hole width of the bent portion 31b of the first magnet through hole 31 is narrower than the hole width of the bent portion 32b of the second magnet through hole 32. The center positions of the curved portions 31b and 32b in the radial direction are set at the same positions. The first concave-convex portion 43 and the second concave-convex portion 44 are formed by the difference in hole widths of the bent portions 31b and 32 b.

As shown in fig. 12, the first concave-convex portion 43 has a plurality of concave portions 43a in the axial direction. The permanent magnet 23 has engaging portions 51 that enter the respective concave portions 43a of the first concave-convex portion 43. The engaging portions 51 are engaged with the concave portions 43a in the axial direction.

The second concave-convex portion 44 has a plurality of concave portions 44a in the axial direction. The permanent magnet 23 has engaging portions 52 that enter the respective concave portions 44a of the second concave-convex portion 44. The engaging portions 52 are engaged with the recess portions 44a in the axial direction. In this example, the depth D1 of the concave portion 43a of the first concave-convex portion 43 is set to be the same as the depth D2 of the concave portion 44a of the second concave-convex portion 44 provided on the outer side surface 42. The depth D1 of the concave portion 43a and the depth D2 of the concave portion 44a become gradually shallower as they approach the linear portion 24a, for example.

The third concave-convex portion 45 is formed by the different shapes of the radially outer end portions of the straight portions 31a, 32a of the first magnet through hole 31 and the second magnet through hole 32. As shown in fig. 14 (a), a protruding portion 31e protruding inward in the hole width direction with respect to the straight portion 31a is formed at the radially outer end portion of the straight portion 31a of the first magnet through hole 31. The protruding portion 31e is formed at an inner corner of the V-shaped folded shape at a radially outer end of the straight portion 31 a. The protruding portion 31e is formed by tapering the inner corner.

As shown in fig. 13, the third concave-convex portion 45 is formed by overlapping a straight portion 31a having the protruding portion 31e and a straight portion 32a having no protruding portion in the axial direction. The third concave-convex portion 45 has a plurality of concave portions 45a in the axial direction. The concave portion 45a is constituted by the straight portion 32a having no protruding portion. The convex portion of the third concave-convex portion 45 is constituted by the protruding portion 31e. The permanent magnet 23 has engaging portions 53 that enter the respective concave portions 45a of the third concave-convex portion 45. The engagement portions 53 are engaged with the concave portions 45a in the axial direction. The protruding portion 31e may be formed in the second magnet through hole 32 instead of the first magnet through hole 31.

As shown in fig. 11, the non-concave-convex portion 46 is a portion of the inner surface of the magnet housing hole 24 where the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are not formed. That is, when the magnet housing hole 24 is viewed from the axial direction, the positions of the peripheral edge portions of the first magnet through hole 31 and the second magnet through hole 32, which overlap in the axial direction, coincide with each other at the non-concave-convex portion 46.

As shown in fig. 11, a coupling portion 61 is provided in the rotor core 22, and the coupling portion 61 is coupled between inner peripheral portions facing each other in the hole width direction at a halfway position of the folded shape corresponding to the magnet accommodating hole 24. The coupling portion 61 is provided in the curved portion 24b of the magnet housing hole 24, for example.

In this example, the coupling portion 61 is formed in only the first magnet through hole 31 out of the first magnet through hole 31 and the second magnet through hole 32. The coupling portion 61 is formed in the curved portion 31b of each first magnet through hole 31. The coupling portion 61 extends in the hole width direction of the bent portion 31b and couples the inner peripheral edge portions opposed to each other in the direction. In the connecting portion 61 of each first magnet through hole 31, the width in the direction orthogonal to the direction in which the connecting portion 61 extends is set to be equal to each other, for example. In addition, in a state where the core pieces 30 are stacked as the rotor core 22, the coupling portions 61 in one magnet housing hole 24 are arranged on a straight line in the axial direction.

In this example, the hole width of the bent portion 31b of the first magnet through hole 31 is smaller than the hole width of the bent portion 32b of the second magnet through hole 32. Therefore, by providing the coupling portion 61 at the bent portion 31b of the first magnet through hole 31, the length of the coupling portion 61 in the hole width direction can be shortened as compared with the case where the coupling portion is provided at the bent portion 32b of the second magnet through hole 32.

In this example, no connection portion is formed in the second magnet through hole 32. Therefore, in the bent portion 24b of the magnet housing hole 24, there is a portion where there is no connecting portion for every other core piece 30. The magnetic material constituting the permanent magnet 23 enters a portion where the connecting portion is not present. The coupling portion 61 is provided between the first concave-convex portion 43 and the second concave-convex portion 44. In other words, the connecting portion 61 connects the first concave-convex portion 43 and the second concave-convex portion 44.

According to the structure shown in fig. 11 to 13, in addition to the two-part connecting portion 22d that is necessarily included in the structure of the magnet housing hole 24, the connecting portion 61 located in the bent portion 24b also supports the outer core portion 25 at the newly added third part. This can improve the centrifugal force strength of the outer core portions 25. The three support points of the two connecting portions 22d and 61 are arranged uniformly around the outer core portion 25. This contributes to stable support of the outer core portions 25.

In the rotor 20 using the permanent magnets 23 of a convex folded shape protruding radially inward, the volume of the outer core portions 25 located radially outward of the permanent magnets 23 becomes large. In addition, in order to achieve higher torque, when the radially outer end portion of the permanent magnet 23 is extended to the vicinity of the outer peripheral surface 22a of the rotor core 22, the wall thickness of the coupling portion 22d tends to be thin, and the strength of the coupling portion 22d tends to be low. Therefore, for example, when an axial vibration force is applied to the rotor 20 due to an external factor, a force is generated that vibrates the outer core portion 25 in the axial direction with the connecting portion 22d as a fulcrum. As a result, a load is applied to the connecting portion 61, and the connecting portion 61 may be deformed without taking any countermeasure.

In this regard, in the structure shown in fig. 11 to 13, the permanent magnet 23 constituted by the bonded magnet filled in the magnet housing hole 24 is engaged with the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 of the magnet housing hole 24 with a so-called anchoring effect. That is, the outer core portion 25 is engaged with the V-shaped inner surface of the permanent magnet 23 in the axial direction by the first concave-convex portion 43 and the third concave-convex portion 45. The V-shaped outer surface of the permanent magnet 23 is engaged with a portion other than the outer core portion 25 of the rotor core portion 22 in the axial direction by the second concave-convex portion 44. Thus, even if an axial vibration force is applied to the rotor 20 by an external factor, for example, the outer core portion 25 can be restrained from vibrating in the axial direction with the connecting portion 22d as a fulcrum. As a result, the load applied to the connecting portion 61 is reduced. In this way, the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 can suppress deformation of the connecting portion 61 due to axial vibration of the outer core portion 25. That is, in the structure as in this example, both the centrifugal force strength and the axial direction strength of the outer core portion 25 can be improved.

In the above example, the non-concave-convex portion 46, which is a portion where the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are not formed, is provided on the inner surface of the magnet housing hole 24. As a result, compared to a structure having the concave-convex portion on the entire inner surface of the magnet housing hole 24, it is possible to suppress leakage magnetic flux in the axial direction generated by the boundary between the magnet housing hole 24 and the permanent magnet 23 being concave-convex.

In addition, in the above example, the inner surface of the magnet housing hole 24 includes the inner side surface 41 forming the outer core part 25 and the outer side surface 42 opposite to the inner side surface 41. The inner side surface 41 is provided with a first concave-convex portion 43 and a third concave-convex portion 45. The outer side surface 42 is provided with a second concave-convex portion 44. According to this structure, since the inner side surface 41 and the outer side surface 42 of the magnet housing hole 24 each have the irregularities, the vibrations of the outer core portion 25 can be more effectively suppressed by the irregularities. Further, since the non-rugged portions 46 are provided on the inner side surface 41 and the outer side surface 42 of the magnet housing hole 24, the effect of suppressing the leakage magnetic flux by providing the non-rugged portions 46 can be more preferably obtained.

In addition, in the above example, the first concave-convex portion 43 and the second concave-convex portion 44 are provided within the range of the reference circle C1 having a half diameter of the outer diameter of the rotor core 22. The reference circle C1 is a circle centered on the axis center O1 of the rotor 20. The range indicated by the reference circle C1 is a range of the rotor core 22 on the radially inner side, that is, a range where it is difficult to contribute to the output. Therefore, by providing the first concave-convex portion 43 within the range of the reference circle C1, the decrease in output due to the provision of the first concave-convex portion 43 can be suppressed to be small.

In the above example, the first concave-convex portion 43 and the second concave-convex portion 44 are provided in the bent portion 24b of the folded shape of the magnet housing hole 24. According to this structure, the radially inner end portion of the outer core portion 25 located at a position distant from the coupling portion 22d can be engaged with the permanent magnet 23 in the axial direction by the first concave-convex portion 43 and the second concave-convex portion 44. Therefore, the axial vibration of the outer core portion 25 about the connecting portion 22d can be effectively suppressed by the first concave-convex portion 43 and the second concave-convex portion 44.

In the above example, the third concave-convex portion 45 is provided at the radially outer end 24c of the magnet housing hole 24. According to this structure, the vibration in the vicinity of the radially outer end portion of the outer core portion 25 can be suppressed. The protruding portion of the third concave-convex portion 45 is formed by a protruding portion 31e protruding inward in the hole width direction of the magnet housing hole 24. The protruding portion 31e is formed in the first magnet through hole 31. This can shorten the circumferential length of the coupling portion 22d corresponding to the first magnet through hole 31. As a result, the formability of the core sheet 30 can be improved.

In addition, the protruding portion 31e is formed as an inner corner of the V-shaped folded shape at the radially outer end of the straight portion 31 a. Accordingly, the magnetic flux of the permanent magnet 23 can be suppressed from decreasing as much as possible, and the third concave-convex portion 45 can be formed by the protruding portion 31 e. Further, by providing the protruding portion 31e, the volume of the permanent magnet 23 can be reduced, and the reduction in magnetic flux can be suppressed as much as possible, so that the output torque per unit volume of the permanent magnet 23 can be improved.

In addition, in the above example, the structures of the plurality of core pieces 30 are identical to each other. The respective core pieces 30 are provided with first magnet through holes 31 and second magnet through holes 32 having the same shape as each other in a mixed manner. In the structure of one magnet housing hole 24, the first magnet through hole 31 and the second magnet through hole 32 are mixed. According to this configuration, the component management can be easily performed by configuring each core piece 30 to be the same, and the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are formed in the magnet housing hole 24 by the first magnet through hole 31 and the second magnet through hole 32 that overlap in the axial direction.

In the above example, the magnetic force imbalance caused by the formation of the first and second magnet through holes 31 and 32 having different shapes from each other in one core piece 30 can be suppressed as much as possible.

In the example shown in fig. 11, the first concave-convex portion 43 and the second concave-convex portion 44 are formed by the difference in the hole widths of the bent portions 31b, 32b of the first magnet through hole 31 and the second magnet through hole 32, but the present invention is not limited to this, and may be appropriately modified.

For example, as shown in fig. 15 and 16, the radial widths of the bent portion 31b of the first magnet through hole 31 and the bent portion 32b of the second magnet through hole 32 may be made equal, and the first concave-convex portion 43 and the second concave-convex portion 44 may be formed by the difference in the radial positions of the bent portions 31b and 32 b. In the structure shown in the figure, the first concave-convex portion 43 and the second concave-convex portion 44 are formed by the difference in radial positions of the bent portion 31b of the first through hole 31 for the magnet and the bent portion 32b of the second through hole 32 for the magnet. The bent portion 31b of the first magnet through hole 31 is located radially inward of the bent portion 32b of the second magnet through hole 32.

With such a configuration, substantially the same effects as those of the configuration shown in fig. 11 can be obtained. In addition, according to the structure shown in fig. 15, the magnetic characteristics of the permanent magnets 23 formed in the respective magnet housing holes 24 are not different from each other, and the first concave-convex portion 43 and the second concave-convex portion 44 can be formed on the inner surface of the magnet housing hole 24. In addition, a combination of a structure in which the positions of the bent portions 31b and 32b are different and a structure in which the hole widths of the bent portions 31b and 32b are different may be employed.

In the above examples, the core pieces 30 were alternately arranged at the first position and the second position rotated 45 ° every other, but may be alternately arranged at the first position and the second position in a plurality of pieces. In this case, the number of pieces may be the same, or the number of pieces may be different. Fig. 17 shows, as an example, a structure in which the core pieces 30 are stacked alternately at a first position and a second position rotated 45 °. With this configuration, the same effects as those of the above-described examples can be obtained.

In the above-described examples, the formation position of the concave-convex portion on the inner surface of the magnet housing hole 24 is not limited to the above-described examples, and can be appropriately changed. For example, a concave-convex portion may be formed on the inner surface of the magnet housing hole 24 at the intermediate portion of the straight portion 24a when viewed in the axial direction.

In the magnet housing hole 24 of each of the above embodiments, any one of the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 may be omitted, for example. In the above-described examples, the coupling portion 61 is provided between the first concave-convex portion 43 and the second concave-convex portion 44, but for example, the coupling portion 61 may be provided in the non-concave-convex portion 46.

In the above example, the first concave-convex portion 43, the second concave-convex portion 44, and the third concave-convex portion 45 are partially formed in the extending direction of the magnet housing hole 24, and the non-concave-convex portion 46 is formed in other portions of the extending direction of the magnet housing hole 24, but is not particularly limited thereto. For example, a concave-convex portion may be formed in a part of the inner surface of the magnet housing hole 24 in the axial direction, and a non-concave-convex portion may be formed in a part other than the concave-convex portion in the axial direction.

As shown in fig. 18, for example, the concave-convex portion 71 may be formed on the entire inner surface of each magnet housing hole 24. In the structure shown in the figure, the first magnet through hole 31 is formed in a shape smaller than the second magnet through hole 32 by one turn. Then, the first magnet through-hole 31 and the second magnet through-hole 32 having the same shape are overlapped in the axial direction, so that the concave-convex portion 71 is formed on the entire inner surface of the magnet housing hole 24. According to such a structure, the area of the concave-convex portion 71 in the inner surface of the magnet housing hole 24 can be ensured to be large. As a result, axial vibration of the outer core portion 25 can be more desirably suppressed.

In the above-described examples, the number of the connecting portions 61 of the first magnet through-holes 31 is one, but two or more may be provided. In this case, the two-part connecting portion 22d that is necessarily included in the structure of the magnet housing hole 24 is added, and the support portions of the outer core portion 25 are four or more in total.

In the above-described examples, the coupling portion 61 is provided in the curved portion 24b of the magnet housing hole 24, but the coupling portion 61 may be provided in a portion other than the curved portion 24b, for example, in the straight portion 24a or the like.

In the above-described examples, the direction in which the connecting portion 61 extends was defined as the radial direction of the rotor 20, which is the hole width direction of the bent portion 24b of the magnet housing hole 24, but may be changed to a direction inclined with respect to the hole width direction, a direction extending in a direction other than the radial direction, or the like, as appropriate.

In the above embodiment and the above modifications, the number of the first magnet through holes 31 and the number of the second magnet through holes 32 are the same in the single core piece 30, but the present invention is not limited to this. That is, in one core piece 30, the number of the first magnet through holes 31 may be larger or smaller than the number of the second magnet through holes 32. In addition, regardless of the number of the first magnet through holes 31 and the second magnet through holes 32, the shapes of the first magnet through holes 31 and the second magnet through holes 32 are formed in a point symmetry about the axis center O1, so that the magnetic force imbalance in the circumferential direction can be suppressed.

For example, in the core piece 30 shown in fig. 19, two through holes 31 for the first magnet are provided, and four through holes 32 for the second magnet are provided. The two first magnet through holes 31 are arranged at 180 ° opposite positions. This can suppress magnetic force unbalance in the circumferential direction. In the example shown in fig. 19, the hole width of the bent portion 31b of the first magnet through hole 31 is narrower than the hole width of the bent portion 32b of the second magnet through hole 32. That is, the thickness of the bent portion 23b of the permanent magnet 23 is thinner at the first magnet through hole 31 than at the second magnet through hole 32. Therefore, by configuring the number of the first magnet through holes 31 to be smaller than the number of the second magnet through holes 32, a decrease in output torque can be suppressed to be small.

In the above embodiment and the above modifications, the core pieces 30 are rotated by 45 ° every other one magnetic pole in the process of stacking the core pieces 30, but the rotation angle at the time of stacking is not limited to 45 ° which is one magnetic pole, and may be an angle other than 45 ° such as two magnetic poles or three magnetic poles.

Technical ideas that can be grasped from the above embodiments and modifications are described.

(A) On the inner surface of the magnet housing hole, there are provided concave-convex portions (43, 44, 45) formed by different positions of the peripheral edge portions of the through hole for the magnet, which are overlapped in the axial direction, and non-concave-convex portions (46) which are portions where the concave-convex portions are not formed.

According to this configuration, since the non-rugged portion is provided on the inner surface of the magnet housing hole, compared with a configuration having the rugged portion on the entire inner surface of the magnet housing hole, it is possible to suppress leakage magnetic flux in the axial direction generated by the rugged boundary between the magnet housing hole and the permanent magnet.

(B) The rotor core has an outer core part (25) which is a part radially outside the permanent magnets,

the inner surface of the magnet housing hole includes an inner side surface (41) forming the outer core portion and an outer side surface (42) opposite to the inner side surface,

the concave-convex portions are provided on the inner side surface and the outer side surface,

the non-concave-convex portions are provided on the inner side surface and the outer side surface, respectively.

According to this structure, since the concave-convex portions are provided on the inner side surface and the outer side surface of the magnet housing hole, the vibration of the outer core portion can be more effectively suppressed by the concave-convex portions. Further, non-concave-convex portions are provided on the inner side surface and the outer side surface of the magnet housing hole, respectively. Therefore, the effect of suppressing the leakage magnetic flux by providing the non-concave-convex portion can be more desirably obtained.

(C) The concave-convex portion is provided radially inward of a half of an outer diameter of the rotor core.

According to this structure, the range radially inward of the half of the outer diameter of the rotor core is a range where it is difficult to contribute to the output. Therefore, by providing the concave-convex portion at a position radially inward of half the outer diameter of the rotor core, the reduction in output due to the provision of the concave-convex portion can be suppressed to be small.

(D) The concave-convex portion is provided in a bent portion (24 b) of the magnet housing hole in a folded shape.

According to this structure, the radially inner end portion of the outer core portion can be engaged with the permanent magnet in the axial direction by the concave-convex portion provided in the curved portion. Therefore, axial vibration of the outer core portion can be effectively suppressed by the concave-convex portion.

(E) The concave-convex portion is provided at a radially outer end (24 c) of the magnet housing hole.

According to this structure, the vibration in the vicinity of the radially outer end portion of the outer core portion can be suppressed.

(F) The convex part of the concave-convex part arranged at the radial outer end part of the magnet accommodating hole is composed of a protruding part (31 e) protruding to the inner side of the hole width direction of the magnet accommodating hole.

According to this configuration, by providing the protruding portion, the circumferential length of the connecting portion formed near the radially outer end portion of the magnet housing hole can be partially shortened. As a result, the formability of the core sheet can be improved.

(G) The protruding portion is formed at an inner corner of the folded shape of the magnet housing hole at a radially outer end portion of the magnet housing hole.

According to this configuration, the permanent magnet can be prevented from decreasing in magnetic flux as much as possible, and the protruding portion can also form the concave-convex portion. In addition, by providing the protruding portion, the volume of the permanent magnet can be reduced, and the reduction in magnetic flux can be suppressed as much as possible, so that the output torque per unit volume of the permanent magnet can be improved.

(H) In the connecting portion of each of the first magnet through holes formed in one of the core pieces, the width in the direction orthogonal to the direction in which the connecting portion extends is set to be equal to each other.

According to this configuration, in the state where the core pieces are stacked as the rotor core, the coupling portions in one magnet housing hole are arranged on a straight line in the axial direction. Therefore, when an axial vibration force is applied to the outer core portion, a substantially uniform load is applied to each connecting portion in one magnet housing hole. Therefore, deformation of the connecting portion can be desirably suppressed.

Although the present disclosure has been described based on the embodiments, it should be understood that the present disclosure is not limited to the above-described embodiments, constructions. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and modes, and other combinations and modes including only one element, more than or equal to the element, are also within the scope and spirit of the present disclosure.

Claims (12)

1. A rotor, the rotor (20) comprising:

a rotor core (22) having a plurality of stacked core pieces (30) and a plurality of magnet accommodating holes (24) having a convex folded shape protruding radially inward; and

a permanent magnet (23) embedded in a magnet accommodating hole of the rotor core,

each of the plurality of core pieces includes a first magnet through hole (31) having a connecting portion (31 c, 61) connecting inner peripheral portions opposed in a hole width direction at intermediate positions of a folded shape corresponding to the magnet accommodating hole, and a second magnet through hole (32) having no connecting portion (31 c, 61),

the plurality of core pieces are identical in structure to one another,

the plurality of core pieces are stacked so that the first magnet through hole and the second magnet through hole are mixed in one of the magnet accommodating holes of the rotor core.

2. The rotor of claim 1, wherein the rotor comprises a plurality of rotor blades,

in each of the plurality of core pieces, the first magnet through holes and the second magnet through holes are alternately arranged in the circumferential direction.

3. A rotor according to claim 2, wherein,

The plurality of core pieces are arranged at any one of a first position and a second position at which the magnet accommodating hole is rotated one amount from the first position at intervals of a predetermined number of pieces.

4. The rotor of claim 3, wherein the rotor comprises a plurality of rotor blades,

the core pieces are arranged at the first position or the second position every other piece.

5. The rotor according to claim 1 to 4,

the first through hole for a magnet has a bent portion (31 b) having a folded shape, and the connecting portion is located at the bent portion (31 b) of the first through hole for a magnet.

6. The rotor according to claim 1 to 5,

the self width (Wb) of the connecting portion is set to be equal to or less than the plate thickness (t) of each of the plurality of core pieces.

7. The rotor according to claim 1 to 6,

the side edge (31 d) of the connecting portion has a uniform curved shape with a narrower width as it approaches the central portion of the connecting portion in the extending direction.

8. The rotor according to claim 1 to 7,

in order to narrow the radial outer end (24 c) of the magnet housing hole, the rotor core has protruding parts (22 e, 22 f) that protrude from one corner of the radial outer end (24 c).

9. The rotor according to claim 1 to 8, wherein,

the permanent magnet has a protruding portion (23 x) at least a part of which protrudes from an axial end face (22 c) of the rotor core.

10. The rotor according to any one of claim 1 to 9, wherein,

the permanent magnet has a bent portion (23 b) having a folded shape, and the thickness (Wm 1) of the bent portion (23 b) is smaller than the thickness (Wm) of the other portion (23 a).

11. The rotor according to any one of claim 1 to 10, wherein,

the inner surface of the magnet housing hole has concave-convex portions (43, 44, 45, 71) formed by the difference between the positions of the peripheral edge portions of the first and second magnet through holes overlapped in the axial direction,

the permanent magnet has engagement portions (51, 52, 53) that enter the concave portions (43 a, 44a, 45 a) of the concave-convex portions.

12. A rotary electric machine (M) includes a rotor (20) and a stator (10),

the rotor includes:

a rotor core (22) having a plurality of stacked core pieces (30) and a plurality of magnet accommodating holes (24) having a convex folded shape protruding radially inward; and

A permanent magnet (23) embedded in a magnet accommodating hole of the rotor core,

the stator applies a rotating magnetic field to the rotor,

each of the plurality of core pieces includes a first magnet through hole (31) having a connecting portion (31 c, 61) connecting inner peripheral portions opposed in a hole width direction at intermediate positions of a folded shape corresponding to the magnet accommodating hole, and a second magnet through hole (32) having no connecting portion (31 c, 61),

the plurality of core pieces are identical in structure to one another,

the plurality of core pieces are stacked so that the first magnet through hole and the second magnet through hole are mixed in one of the magnet accommodating holes of the rotor core.