Embedded magnet-type rotor and rotating electric machine

Abstract

According to an embodiment, an embedded magnet-type rotor (30) is provided with: a rotor shaft; a rotor core (10) attached to the outer periphery of the rotor shaft; and permanent magnets (3) provided in the rotor core (10) and disposed so as to form a pair or a plurality of pairs with each other at each magnetic pole part. The rotor core (10) is provided with: an inner iron core (12) attached to the outer periphery of the rotor shaft; a fan-shaped outer iron core in each magnetic pole part; a filling member that fills the space between the inner iron core and the outer iron core; and a positioning member capable of maintaining the relative positions of the inner iron core and the respective outer iron cores. The inner iron core and the outer iron core are formed so as to be engaged with each other via the filling member.

Description

Interior permanent magnet rotor and rotating electric machine

[0001] The present invention relates to an interior permanent magnet rotor and a rotating electric machine using the same.

[0002] Permanent magnet rotors generally include an embedded magnet rotor in which the permanent magnets are arranged inside the rotor core, and a surface magnet rotor in which the permanent magnets are arranged on the outer periphery of the rotor core.

[0003] In interior permanent magnet rotors, a method is often adopted in which a storage hole for storing a permanent magnet is formed in the rotor core and the permanent magnet is press-fitted into this storage hole.

[0004] Here, permanent magnets are sintered products similar to china, and are brittle with large dimensional tolerances. Therefore, chips and scratches are likely to occur where they come into contact with the wall of the housing hole during press-fitting. Furthermore, if the surface of the permanent magnet is coated with an anti-rust agent or other coating, the coating is likely to peel off. Furthermore, when the permanent magnet is pressed into place, the electromagnetic steel sheets that make up the rotor core deform unevenly, causing them to bulge outward in the radial direction. This results in unevenness on the circumferential surface of the rotor core, which can cause magnetic noise and torque ripple. To avoid these problems, processes such as polishing are required to improve the dimensional tolerances of the permanent magnets, but such additional processes significantly increase costs.

[0005] To solve this problem and reduce leakage flux, a method has been proposed in which the top bridge (bridge on the outer periphery) and center bridge (bridge on the d-axis between the magnets) are not provided. That is, a method has been proposed in which the radially outer and radially inner parts of each magnetic pole are separated and then assembled together with the permanent magnets.

[0006] Fig. 6 is a partial cross-sectional view showing a conventional example of an interior permanent magnet rotor 1. As described above, Fig. 6 shows that rotor core 10 of interior permanent magnet rotor 1 has inner core 12, which is the radially inner portion, and outer core 11, which is the radially outer portion of each magnetic pole portion 3a. Outer core 11 and inner core 12 are separated from each other and are separate bodies.

[0007] Outer core 11 has outer core extension 11a extending radially inward, and two outer core engaging portions 11b connected to the innermost part of outer core extension 11a and extending on both sides in the circumferential direction. Inner core 12 has two inner core engaging portions 12a formed to engage with outer core engaging portions 11b of outer core 11. Outer core engaging portion 11b and inner core engaging portion 12a have overlapping portions when viewed from the radially inner side to the radially outer side.

[0008] A part of the space formed by outer core 11 and inner core 12 serves as magnet storage hole 15 for storing permanent magnet 3 .

[0009] At least a portion of magnet storage hole 15 and the space between outer core engaging portion 11b and inner core engaging portion 12a are filled with filler 18. Outer core 11 and inner core 12 are connected and integrated by filler 18. As a result, when interior permanent magnet rotor 1 is rotating, centrifugal force acting on permanent magnet 3 and outer core 11 is transmitted from outer core engaging portion 11b to inner core engaging portion 12a via filler 18. In other words, even during rotation, permanent magnet 3 and outer core 11 are held by inner core engaging portion 12a, overcoming the centrifugal force.

[0010] With this configuration, it is possible to assemble outer core 11, permanent magnet 3, and inner core 12. Therefore, there is no need to press-fit permanent magnet 3 into magnet housing hole 15 of rotor core 10.

[0011] JP 2011-109786 A

[0012] The interior permanent magnet rotor 1 shown in FIG. 6 does not require press-fitting the permanent magnets 3 into the magnet housing holes 15 of the rotor core 10, which has the advantage of eliminating the problems associated with press-fitting, but it also has significant problems.

[0013] That is, when filling material 18 is filled between outer core 11 and inner core 12 and integrated, outer core 11 and inner core 12 need to be positioned relative to each other in a predetermined relationship. That is, inner core 12 and the same number of outer cores 11 as magnetic pole portions 3 a need to be arranged in predetermined relative positions, and the relative positional relationship between outer core 11, inner core 12, and permanent magnet 3 needs to be maintained until filling material 18 is poured and solidified.

[0014] If accurate positioning is not possible, the outer periphery of outer core 11 must be positioned radially inward to avoid contact between interior permanent magnet rotor 1 and the stator. In other words, the outer diameter of the rotor must be reduced to increase the gap width between the rotor and the stator. As a result of increasing the gap width, there has been a problem of increased magnetic resistance, which reduces or varies the torque performance.

[0015] On the other hand, if accurate positioning is to be performed, dedicated jigs and devices are required, and the number of steps required for positioning increases, resulting in increased manufacturing costs.

[0016] An object of the present invention is to provide an interior permanent magnet rotor and a rotating electric machine that enable positioning of outer core 11 and inner core 12 .

[0017] In order to achieve the above-mentioned object, an embedded magnet rotor according to an embodiment of the present invention is an embedded magnet rotor comprising: a rotor shaft extending in the direction of rotation axis; a rotor core attached to the outer periphery of the rotor shaft; and permanent magnets provided within the rotor core and arranged in one or more pairs circumferentially at each magnetic pole portion, wherein the rotor core comprises: an inner core attached to the outer periphery of the rotor shaft and having a permanent magnet support inner recess formed to support each of the permanent magnets; a fan-shaped outer core arranged radially outside the inner core at each of the magnetic pole portions; a filler member filled between the inner core and the outer core; and a positioning member capable of maintaining the relative position of the inner core and each of the outer cores, wherein the inner core and the outer core are formed so that the inner core and the outer core engage with each other via the filler member at the radially innermost part of the outer core.

[0018] Fig. 1 is a longitudinal sectional view showing a rotating electric machine according to a first embodiment; Fig. 2 is a transverse sectional view showing a rotating electric machine according to the first embodiment; Fig. 3 is a partial transverse sectional view showing an interior permanent magnet rotor according to the first embodiment; Fig. 4 is a partial transverse sectional view showing an interior permanent magnet rotor according to a second embodiment; Fig. 5 is a partial transverse sectional view showing an interior permanent magnet rotor according to a third embodiment; Fig. 6 is a partial transverse sectional view showing a conventional example of an interior permanent magnet rotor;

[0019] Hereinafter, an interior permanent magnet rotor and a rotating electrical machine using the same according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, identical or similar parts will be designated by common reference numerals and redundant description will be omitted.

[0020] [First embodiment] Fig. 1 is a longitudinal sectional view showing a rotating electric machine 100 according to a first embodiment. Fig. 2 is a transverse sectional view showing the rotating electric machine 100 according to the first embodiment. That is, Fig. 1 shows a cross section of the rotating electric machine 100 taken along a vertical plane including a rotation axis CL, and Fig. 2 shows a cross section of the rotating electric machine 100 taken along a plane perpendicular to the rotation axis CL.

[0021] The rotating electric machine 100 has an embedded magnet rotor 30, a stator 40 arranged radially outside the embedded magnet rotor 30 via a gap portion 5 to surround the embedded magnet rotor 30, a bearing 50, and a housing 60 that houses the stator 40, etc. and statically supports the bearing 50.

[0022] The stator 40 has a stator core 41 and a stator winding 42 having a portion accommodated in a plurality of stator slots 41 a ( FIG. 2 ) formed in the stator core 41 .

[0023] The embedded magnet rotor 30 has a rotor shaft 2 that extends in the rotation axis direction (hereinafter referred to as the axial direction) and is rotatably supported by bearings, a rotor core 10 attached to the rotor shaft 2, and a plurality of permanent magnets 3 embedded in the rotor core 10.

[0024] As shown in Figure 2, the multiple permanent magnets 3 are arranged so that two permanent magnets form one pair or multiple pairs in the circumferential direction in each magnetic pole portion 3a. Figure 2 shows an eight-pole rotor having eight magnetic pole portions 3a. Each permanent magnet 3 is arranged so that its north pole and south pole are oriented in such a way that magnetic flux is generated between adjacent magnetic pole portions 3a.

[0025] 3 is a partial cross-sectional view showing the interior permanent magnet rotor 30 according to the first embodiment, which shows the magnetic pole portions 3a.

[0026] As described above, in each magnetic pole portion 3a, two permanent magnets 3 are arranged in one or more pairs in the circumferential direction. Specifically, the two permanent magnets 3 are arranged in a V-shape that extends radially outward. Each permanent magnet 3 is housed in a magnet housing hole 15.

[0027] In each magnetic pole portion 3 a, rotor core 10 has an inner core 12 directly attached to rotor shaft 2 ( FIG. 1 ) and an outer core 11 disposed radially outward of inner core 12. That is, rotor core 10 has one inner core 12 and the same number of outer cores 11 as the number of magnetic pole portions 3 a.

[0028] Outer core 11 has a sector shape that spreads outward in the radial direction, and inner core 12 has a sector-shaped recess corresponding to this in each magnetic pole portion 3a.

[0029] In each magnetic pole portion 3 a, inner core 12 and outer core 11 form two magnet storage holes 15 that each house two permanent magnets 3. An outer space 16 is formed radially outward from magnet storage holes 15, and communicates with gap portion 5 outside rotor core 10. The space between inner core 12 and outer core 11, including magnet storage holes 15, is filled with filler 18. Here, filler 18 is a resin such as a thermosetting resin. Filler 18 fills the entire magnet storage hole 15 or its radially inner portion, and the space radially inside magnet storage hole 15.

[0030] Inner core 12 and outer core 11 have engaging portions 14 at the radially inner portion of outer core 11, which engage with each other via filler member 18. Outer core 11 has outer core extension portion 11a extending toward the radially innermost portion, and the radially innermost portion of outer core extension portion 11a is connected to two outer core engaging portions 11b formed to extend on both sides in the circumferential direction. In addition, inner core 12 has inner core engaging portions 12a arranged radially outward of each outer core engaging portion 11b.

[0031] Filler 18 is filled between two outer core engaging portions 11b and two inner core engaging portions 12a. Filler 18 filled between two outer core engaging portions 11b and two inner core engaging portions 12a forms engaging portion 14. Engaging portion 14 prevents outer core 11 from moving radially outward due to centrifugal force, and has a function of preventing outer core 11 from coming off.

[0032] Two positioning inner bridges 21 are provided between the inner circumferential surface of outer core engaging portion 11 b of outer core 11 and inner core 12 facing it.

[0033] Positioning inner bridge 21 is not a strength member that resists the centrifugal force acting on outer core 11 and permanent magnet 3. In this regard, strength is ensured by outer core 11 and inner core 12 being integrated by engaging portion 14 and filling member 18. Positioning inner bridge 21 as positioning member 20 only needs to have the strength necessary for the positioning function of maintaining the relative positional relationship between inner core 12 and each outer core 11 when assembling rotor core 10. In other words, as long as it has the width necessary for the positioning function, it is preferable that the width be as narrow as possible from the viewpoint of suppressing an increase in leakage flux.

[0034] In interior permanent magnet rotor 30 of the present embodiment configured as described above, inner core 12 and each outer core 11 are connected by positioning inner bridges 21 at each engaging portion 14. Therefore, even when assembling rotor core 10, the relative positional relationship between inner core 12 and each outer core 11 is maintained and they do not become misaligned. That is, each engaging portion 14 has a positioning function. Reducing variation in the relative position between outer core 11 and inner core 12 reduces variation in torque performance, resulting in improved torque performance.

[0035] Furthermore, since the positioning inner bridge 21 has a width as narrow as possible while still ensuring the width necessary for the positioning function, an increase in leakage flux is also minimized.

[0036] 4 is a partial cross-sectional view showing an interior permanent magnet rotor 30a according to a second embodiment. This embodiment is a modification of the first embodiment, and differs in part from the configuration of the engagement portion 14. The rest is the same as the first embodiment.

[0037] Specifically, there are two outer core extensions 11a in the circumferential direction, with extension barrier 11c formed between them. As a result, the rigidity of the base of fan-shaped outer core 11 can be improved. Furthermore, if the rigidity value is maintained at the value for a single outer core extension, the total width of the two outer core extensions 11a of this embodiment can be made smaller than the width of outer core extension 11a of the first embodiment. As a result, the width of the magnetic path of leakage magnetic flux can be reduced, thereby reducing leakage magnetic flux.

[0038] [Third Embodiment] Figure 5 is a partial cross-sectional view showing an interior permanent magnet rotor 30b according to a third embodiment. This embodiment is a modification of the first embodiment. This embodiment differs from the first embodiment in the positioning member 20. The rest of the configuration is the same as the first embodiment.

[0039] In this embodiment, a positioning outer bridge 22 is provided as a positioning member 20 instead of the positioning inner bridge 21 in the first embodiment.

[0040] Positioning outer bridge 22 is provided so as to straddle the communication portion between each magnet storage hole 15 and gap portion 5 of outer space 16 adjacent to the radially outer side of each magnet storage hole 15. In other words, positioning outer bridge 22 is provided so as to connect the outer periphery of outer core 11 and the outer periphery of inner core 12.

[0041] Positioning outer bridge 22 serving as positioning member 20 is not a strength member for resisting bending forces applied to outer core 11. In this regard, strength is ensured by outer core 11 and inner core 12 being integrated by engaging portion 14 and filling member 18. Like positioning inner bridge 21 in the first embodiment, positioning outer bridge 22 serving as positioning member 20 only needs to have the strength required for the positioning function of maintaining the relative positional relationship between inner core 12 and each outer core 11 during assembly of rotor core 10. In other words, as long as it has the width required for the positioning function, it is preferable that the width be as narrow as possible from the viewpoint of suppressing an increase in leakage flux.

[0042] In interior permanent magnet rotor 30b of the present embodiment configured as described above, inner core 12 and each outer core 11 are connected by positioning outer bridges 22 at each engaging portion 14. Therefore, even when assembling rotor core 10, the relative positional relationship between inner core 12 and each outer core 11 is maintained and they do not shift relative to each other. Suppressing variation in the relative position of outer core 11 and inner core 12 suppresses variation in torque performance, resulting in improved torque performance.

[0043] Furthermore, since the positioning outer bridge 22 has a width as narrow as possible while still ensuring the width necessary for the positioning function, an increase in leakage flux is also minimized.

[0044] According to the embodiment described above, it is possible to provide an interior permanent magnet rotor and a rotating electric machine that enable positioning of outer core 11 and inner core 12 .

[0045] [Other Embodiments] Although the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention. Furthermore, features of each embodiment may be combined. For example, the features of the second embodiment may be combined with the features of the third embodiment. Furthermore, the embodiments may be implemented in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. The embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims.

[0046] 1... interior permanent magnet rotor, 2... rotor shaft, 3... permanent magnet, 3a... magnetic pole portion, 5... gap portion, 10... rotor core, 11... outer core, 11a... outer core extension portion, 11b... outer core engagement portion, 11c... extension barrier, 12... inner core, 12a... inner core engagement portion, 13... outer barrier, 14... engagement portion, 15... magnet storage hole, 16... outer space, 18... filling member, 20... positioning member, 21... positioning outer peripheral bridge, 22... positioning inner bridge, 30, 30a, 30b... interior permanent magnet rotor, 40... stator, 41... stator core, 41a... stator slot, 42... stator winding, 50... bearing, 60... housing, 100... rotating electric machine

Claims

1. An embedded magnet type rotor comprising: a rotor shaft extending in the direction of rotation axis; a rotor core attached to the outer periphery of the rotor shaft; and permanent magnets provided within the rotor core and arranged in one or more pairs circumferentially at each magnetic pole portion, wherein the rotor core comprises: an inner core attached to the outer periphery of the rotor shaft; a sector-shaped outer core arranged radially outside the inner core at each of the magnetic pole portions; a filling material filled between the inner core and the outer core; and a positioning member capable of maintaining the relative position of the inner core and each of the outer cores, wherein the inner core and the outer cores are formed so that the inner core and the outer core engage with each other via the filling material at the radially innermost part of the outer core.

2. The embedded magnet rotor as described in claim 1, characterized in that the radially innermost portion of each of the outer cores has two outer core engagement portions formed to extend on both circumferential sides, the inner core has an inner core engagement portion arranged to be radially outward of each of the outer core engagement portions, and the positioning member has at least one positioning inner bridge connecting each of the outer core engagement portions and the inner core engagement portion.

3. The interior magnet rotor according to claim 2, wherein the outer core has two parallel outer core extensions that connect to the outer core engagement portion.

4. The interior magnet rotor according to claim 1, characterized in that the positioning member has a positioning outer periphery bridge that connects adjacent circumferential portions of the outer periphery of the outer core and the outer periphery of the inner core.

5. A rotating electric machine comprising: an embedded magnet type rotor according to any one of claims 1 to 4; a stator arranged radially outside the embedded magnet type rotor; and a bearing that rotatably supports the rotor shaft.

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