CN113783326A - Motor and rotor thereof - Google Patents

Abstract

The invention relates to a motor and a rotor thereof, wherein the rotor comprises a rotor iron core and permanent magnets fixed in the rotor iron core, the rotor iron core comprises a plurality of groups of iron core sections which are arranged at intervals along the circumferential direction, each group of iron core sections comprises two independent subsections, and the permanent magnets extending along the radial direction are arranged between the two subsections. According to the rotor provided by the invention, each iron core section adopts one permanent magnet to form two magnetic poles, so that the using amount of the permanent magnet is effectively reduced, and the manufacturing cost is reduced.

Description

Motor and rotor thereof

Technical Field

The invention relates to the technical field of motors, in particular to a permanent magnet motor and a rotor thereof.

Background

In a common permanent magnet motor, all magnetic poles of a rotor are formed by permanent magnets, that is, the number of the permanent magnets is equal to that of the magnetic poles, so that the usage amount of the permanent magnets is large, and the manufacturing cost is high.

Disclosure of Invention

In view of the above, the present invention is directed to a rotor and a motor having the same, which can solve the above problems.

To this end, the present invention provides an electric machine rotor, including a rotor core and permanent magnets fixed in the rotor core, where the rotor core includes a plurality of sets of core segments arranged at intervals along a circumferential direction, each set of core segments includes two independent sub-segments, and a permanent magnet extending in a radial direction is disposed between the two sub-segments.

Preferably, the permanent magnets are magnetized in a direction perpendicular to a radial direction of the rotor core such that outer circumferential surfaces of the subsections on both sides of the permanent magnets have different polarities.

Preferably, the two sub-sections of each set of core sections are symmetrical with respect to the radial direction of the rotor core, each sub-section is substantially triangular, and the side face of one of the two sub-sections opposite to the other of the two sub-sections extends in the radial direction of the rotor core.

Preferably, a distance between two adjacent core segments gradually increases from an outer circumferential surface of the rotor core toward an axis of the rotor core.

Preferably, the shape of the gap between two adjacent sets of core segments is different from the shape of the gap between two said subsections of each set of core segments.

Preferably, two circumferentially opposite side surfaces of the core segment are inclined at the same angle with respect to a radial direction of the rotor core.

Preferably, the motor rotor further comprises a rotating shaft or a bearing penetrating through the rotor core, and the rotating shaft or the bearing and the rotor core are integrally connected in an overmolded mode by using plastics.

Preferably, the outer peripheral side of each sub-segment includes a protrusion in the middle and radially inwardly recessed grooves formed on both sides of the protrusion, and the radially inner side and the radially outer side of the permanent magnet are flush with the inner peripheral side of the core segment and the bottom wall of the groove, respectively.

In yet another aspect, the present invention also provides an electric machine including a stator and the rotor.

Preferably, the stator includes a plurality of teeth and three-phase windings wound around the teeth, and each phase winding includes at least two windings wound around different teeth connected in series.

Preferably, a non-uniform air gap is provided between the stator and the rotor.

In the rotor provided by the invention, each iron core section adopts one permanent magnet to form two magnetic poles. Therefore, compared with the prior art, under the condition of forming the same number of poles, only half of the existing permanent magnets are needed, the using amount of the permanent magnets is effectively reduced, and the manufacturing cost is reduced.

Drawings

Fig. 1A is a plan view of a motor according to a first embodiment of the present invention.

Fig. 1B is an exploded view of the motor shown in fig. 1A.

Fig. 1C is a partially enlarged view of the motor shown in fig. 1A.

Fig. 1D is a connection embodiment of the a-phase winding of the motor shown in fig. 1A.

Fig. 1E is another connection embodiment of the a-phase winding of the motor shown in fig. 1A.

Fig. 1F is yet another connection embodiment for the a-phase winding of the motor shown in fig. 1A.

Fig. 1G is an embodiment of another motor relative to the motor shown in fig. 1A.

Fig. 2A is a plan view of a motor according to a second embodiment of the present invention.

Fig. 2B is an exploded view of the motor shown in fig. 2A.

Fig. 3A is a plan view of a motor according to a third embodiment of the present invention.

Fig. 3B is an exploded view of the motor shown in fig. 3A.

Fig. 3C is a partial enlarged view of the motor shown in fig. 3A.

Fig. 4A is a plan view of a motor according to a fourth embodiment of the present invention.

Fig. 4B is an exploded view of the motor shown in fig. 4A.

Fig. 5A is a plan view of a motor according to a fifth embodiment of the present invention.

Fig. 5B is an exploded view of the motor shown in fig. 5A.

Fig. 6A is a plan view of a motor according to a sixth embodiment of the present invention.

Fig. 6B is an exploded view of the motor shown in fig. 6A.

Fig. 7A is a plan view of a motor according to a seventh embodiment of the present invention.

Fig. 7B is an exploded view of the motor shown in fig. 7A.

Fig. 8A is a plan view of a motor according to an eighth embodiment of the present invention.

Fig. 8B is an exploded view of the motor shown in fig. 8A.

Fig. 9A is a plan view of a motor according to a ninth embodiment of the present invention.

Fig. 9B is an exploded view of the motor shown in fig. 9A.

Detailed Description

The invention will be described in detail with reference to the accompanying drawings and specific embodiments, so that the technical scheme and the beneficial effects of the invention are more clear. It is to be understood that the drawings are provided for purposes of illustration and description only and are not intended as a definition of the limits of the invention, but are drawn to scale.

Referring to fig. 1A to 1C, a motor 100 according to a first embodiment of the present invention includes an annular stator 10 having a receiving cavity 13, and a rotor 20 received in the receiving cavity 13 and rotatable relative to the stator 10. The rotor 20 includes a rotor core 30 made of a magnetically conductive metal material, and permanent magnets 40 fixed to an outer circumferential surface of the rotor core 30. The permanent magnet 40 serves as a first magnetic pole 41 of the rotor 20. In this embodiment, the rotor core 30 is integrally formed with a dummy second magnetic pole 31. In other words, the second magnetic pole 31 is not formed by the permanent magnet 40. The second magnetic poles 31 and the first magnetic poles 41 are alternately arranged in the circumferential direction of the rotor core 30. In the present embodiment, the virtual second magnetic pole 31 is designed so as to function as an opposite magnetic pole with respect to the adjacent permanent magnet 40. For example, all the permanent magnets 40 may function as N-poles or S-poles, and correspondingly, the second magnetic poles 31 function as S-poles or N-poles opposite thereto. Therefore, compared with the prior art, under the condition of forming the same number of poles, only half of the existing permanent magnets are needed, the using amount of the permanent magnets is effectively reduced, and the manufacturing cost is reduced.

In this embodiment, the rotor core 30 is an annular integrated member. Preferably, the rotor core 30 is formed by stacking a plurality of annular rotor laminations. The rotor core 30 is formed at a middle portion thereof with a mounting hole 32 penetrating itself in an axial direction. The outer peripheral side of rotor core 30 is formed with a plurality of grooves 33 arranged at intervals. Each groove 33 penetrates the rotor core 30 in a direction parallel to the axis of the rotor core 30. An arc-shaped protrusion 34 is formed between one circumferential side of each groove 33 and its adjacent groove 33, and a mounting portion 35 is formed between the other circumferential side and its adjacent groove 33. The projections 34 are used to form the virtual second magnetic pole 31. The mounting portion 35 is used to fix the permanent magnet 40. That is, the permanent magnet 40 in the present embodiment is fixed to the outer peripheral side of the rotor core 30. In other words, the motor 100 in the present embodiment is a surface mount permanent magnet motor (SPM). The design of the groove 33 is such that adjacent first and second poles 41, 31 are circumferentially spaced to reduce end leakage flux. Preferably, the plurality of grooves 33 are equally angularly spaced in the circumferential direction. The bottom wall 330 of each recess 33 is preferably planar. The mounting portion 35 and the protrusion 34 have different heights in the radial direction compared with the bottom wall 330 of the groove 33, and preferably, the radial height H1 of the protrusion 34 compared with the bottom wall 330 of the groove 33 is greater than the radial height H2 of the mounting portion 35 compared with the bottom wall 330 of the groove 33.

Preferably, the outer peripheral side 340 of the projection 34 is arcuate. The two circumferentially opposite side surfaces 341, 342 of the projection 34 are planar and preferably extend obliquely at a first obtuse angle θ 1 to the bottom wall 330 of the respective groove 33. Preferably, the outer peripheral side 350 of the mounting portion 35 is planar. The two circumferentially opposite side surfaces 351, 352 of the mounting portion 35 are planar and preferably extend obliquely to the bottom wall 330 of the groove 33 at a second obtuse angle θ 2 equal to the first obtuse angle θ 1.

Preferably, the permanent magnet 40 is made of a rare earth magnet such as neodymium iron boron. The permanent magnet 40 made of a rare earth magnet is more magnetic than the permanent magnet 40 made of a ferrite magnet, and the resulting rotor 20 is more compact and lighter in weight. In the present embodiment, the permanent magnet 40 is substantially bar-shaped, and includes an inner circumferential side 42 and an outer circumferential side 43 that are diametrically opposed, two side surfaces 44, 45 that are circumferentially opposed, and a top surface 46 and a bottom surface 47 that are axially opposed. The top and bottom surfaces 46, 47 of the permanent magnet 40 are planar and preferably flush with the top and bottom surfaces 353, 354, respectively, of the mounting portion 35. The two side surfaces 44, 45 of the permanent magnet 40 are planar and preferably coplanar with the two side surfaces 351, 352 of the mounting portion 35, respectively. The inner peripheral side 42 of the permanent magnet 40 is planar and preferably completely overlaps the outer peripheral side 350 of the mounting portion 35. The outer peripheral side 43 of the permanent magnet 40 is arc-shaped and preferably on the same cylindrical surface as the outer peripheral side 340 of the projection 34. More preferably, the permanent magnet 40 forms a first magnetic pole 41 with a polar arc angle θ 4 that is not equal to the polar arc angle θ 3 of the second magnetic pole 31 formed by the protrusion 34, e.g., θ 4 ≦ θ 3.

In this embodiment, 4 permanent magnets 40 are fixed to the outer peripheral side of the rotor core 30, and 4 protrusions 34 are correspondingly formed, and the 4 permanent magnets 40 and the 4 protrusions 34 are alternately distributed one by one in the circumferential direction. In other words, the rotor 20 of the present embodiment includes 8 magnetic poles, i.e., the number of pole pairs is 4.

When assembling, all the permanent magnets 40 may be fixed (e.g., glued) to the mounting portion 35 with their radially inner portions as the S-poles and radially outer portions as the N-poles. In other words, the permanent magnets 40 in the present embodiment are magnetized in the radial direction of the rotor core 30 so that the radially inner side and the radially outer side of the permanent magnets 40 have different polarities. In this case, the first magnetic pole 41 formed by the permanent magnet 40 is an N-pole. Accordingly, the second magnetic pole 31 formed by the projections 34 is an S pole, thereby forming N poles and S poles alternately arranged in the circumferential direction. Or vice versa. The rotating shaft or the bearing is then fitted to the mounting hole 32 of the rotor core 30. For example, the shaft is positioned in the mounting hole 32 (at this time, an annular space is formed between the shaft and the wall of the mounting hole 32), and then the shaft and the rotor core 30 are integrally connected by plastic (such as PPS, PA66, or PBT) using Over-Mold (Over-Mold). In another embodiment, the permanent magnet 40 and the outer periphery of the projection 34 may be covered with plastic, so that the permanent magnet 40 and the rotor core 30 are connected more firmly.

The stator 10 includes a stator core 50, an insulation frame (not shown) covering the stator core 50, and a plurality of sets of windings (not shown) wound around the insulation frame. The stator core 50 includes a ring-shaped yoke portion 51 and a plurality of tooth portions 52 connected to the inside of the yoke portion 51. A winding slot 53 is formed between adjacent teeth 52 for receiving a winding. Each tooth 52 is wound with a winding. In this embodiment, the stator 10 includes a three-phase winding: the phase-type motor comprises a phase-A winding, a phase-B winding and a phase-C winding, wherein the windings of each phase winding are at least partially connected in series so as to enable back electromotive force to be symmetrical. In this embodiment, an 8-pole 12-slot motor is taken as an example for explanation, and each phase winding includes 4 windings. The stator 10 in this embodiment includes 12 windings. Accordingly, 12 winding slots 53 are formed in the stator. As shown in fig. 1A, the a-phase winding includes 4 windings wound around the teeth 1, 2, 7, and 8, the B-phase winding includes 4 windings wound around the teeth 3, 4, 9, and 10, and the C-phase winding includes 4 windings wound around the teeth 5, 6, 11, and 12. The connection of the windings will be described below by taking the a-phase winding as an example.

Referring to fig. 1D, in one embodiment, the windings on tooth 1 and the windings on tooth 8 are connected in series, the windings on tooth 2 and the windings on tooth 7 are connected in series, and the windings on the series-connected teeth 1, 8 are connected in parallel with the windings on the series-connected teeth 2, 7. Referring to fig. 1E, in another embodiment, the windings on tooth 1 and the windings on tooth 7 are connected in series, the windings on tooth 2 and the windings on tooth 8 are connected in series, and the windings on the series of teeth 1, 7 are connected in parallel with the windings on the series of teeth 2, 8. Referring to fig. 1F, in yet another embodiment, the windings on the teeth 1, 2, 7, 8 are all connected in series. For the windings of the B-phase and C-phase, reference may be made to the foregoing embodiments, and details are not repeated here.

As can be seen from the above, the motor 100 in this embodiment is an 8-pole 12-slot motor. It will be appreciated that in other embodiments, motors of other pole and slot counts, such as 10 poles, 12 slots, etc., may be used. The subsequent fifth to ninth embodiments give examples of some other applications.

In other embodiments, an uneven air gap may be used between the rotor and the stator to make the back electromotive force of the motor form a symmetrical sine wave, so as to reduce noise and vibration of the motor. For example, referring to fig. 1G, a motor 100' of another embodiment is similar to the motor 100 of the first embodiment, and the same parts are not repeated herein. The motor 100' of the other embodiment is mainly different from the motor 100 of the first embodiment in that: the first magnetic pole 40 'of the rotor 20' is located on a circle having a different diameter from the circle on which the second magnetic pole 31 is located. Specifically, the outer surfaces of the first magnetic pole 40' and the second magnetic pole 31 are both arc-shaped, and the radial height H3 of the first magnetic pole 40' and the mounting part 35 relative to the bottom wall of the groove 33 is smaller than the radial height H1 of the second magnetic pole 31 relative to the bottom wall of the groove 33, so that the diameter of the circle where the first magnetic pole 40' is located is smaller than the diameter of the circle where the second magnetic pole 31 is located. Therefore, the radial air gap of the stator 10 with the first magnetic pole 40' is larger than the radial air gap with the second magnetic pole 31. This arrangement allows the back emf of the motor to be a symmetrical sine wave. It will be appreciated that in other embodiments, the diameter of the circle on which the first pole is located may be larger than the diameter of the circle on which the second pole is located. The shape of the stator teeth may be changed so that the inner circumferential surfaces in the radial direction of the stator teeth do not form an uneven air gap between the stator and the rotor on the same circumference.

Referring to fig. 2A and 2B, a motor 200 according to a second embodiment of the present invention is similar to the motor 100 according to the first embodiment, and is also an 8-pole 12-slot surface-mount permanent magnet motor, and the same parts are not repeated herein. The main differences between the motor 200 of the present embodiment and the motor 100 of the first embodiment are: the rotor core 130 in the present embodiment includes a plurality of core segments 132 arranged at intervals in the circumferential direction, and the permanent magnet 40 is fixed to the outer circumferential side of each core segment 132. In other words, the rotor core 130 in the present embodiment is not one integral piece by itself, but adopts a segmented core structure. The rotor core 130 of the segmented core structure reduces magnetic leakage between the core segments 132, improves the efficiency of the motor, and reduces noise of the motor. In addition, the use of the segmented core structure also contributes to reduction in the amount of the rotor core 130 used, and cost reduction.

Specifically, the rotor core 130 in the present embodiment has an annular shape as a whole, and includes a plurality of (4 in the present embodiment) core segments 132 that are uniformly spaced in the circumferential direction. Each core segment 132 may be formed from a stack of laminations. Each core segment 132 is generally fan-shaped and includes radially opposed inner and outer peripheral sides 1320, 1321, circumferentially opposed first and second side surfaces 1322, 1323, and axially opposed top and bottom surfaces 1324, 1325. The inner peripheral sides 1320 of the core segments 132 are curved in an arc, and the inner peripheral sides 1320 of the 4 core segments 132 are preferably on the same cylindrical surface. The outer peripheral side 1321 of the core segment 132 forms a recess 133. One circumferential side of the groove 133 is a projection 134 for forming the second magnetic pole, and the other circumferential side of the groove 133 is a mounting portion 135 for mounting the permanent magnet 40. The first side 1322 of the core segment 132 connects one end of the projection 134 remote from the groove 133 and the inner peripheral side 1320 of the core segment 132. The second side 1323 of the core segment 132 connects one end of the mounting portion 135 remote from the groove 133 and the inner peripheral side 1320 of the core segment 132. Preferably, the length of the first side surface 1322 (from the end of the protrusion 134 on the side away from the groove 133 to the inner circumferential side 1320 of the core segment 132) is smaller than the length of the second side surface 1323 (from the end of the mounting portion 135 on the side away from the groove 133 to the inner circumferential side 1320 of the core segment 132). In other words, the area of the rotor core corresponding to the permanent magnet 40 is smaller than the area of the rotor core corresponding to the protrusion 134, so that the magnetic circuit can be optimized, and the interval between two adjacent core segments 132 is larger than that of the symmetrically disposed core segments, which contributes to reducing the leakage flux, improving the motor efficiency, and reducing noise. In this embodiment, an included angle α 1 formed between the first side surface 1322 and the radial direction of the motor (a connecting line connecting the motor shaft and the outer peripheral end point of the iron core) is smaller than an included angle α 2 formed between the second side surface 1323 and the radial direction of the motor. Of course, in other embodiments, just in contrast to the above-described embodiment, the area of the rotor core corresponding to the permanent magnet 40 is smaller than the area of the rotor core corresponding to the projection 134, and the same effects as those of the present embodiment can be obtained. That is, the first and second side surfaces 1322, 1323 may have the same or different angles with respect to the radial direction of the motor (a line connecting the motor shaft and the outer circumferential end of the core), or one of the first and second side surfaces 1322, 1323 may be disposed along the radial direction of the motor and the other side surface may have a predetermined inclination angle with respect to the radial direction of the motor.

During assembly, the permanent magnets 40 may be fixed to the corresponding core segments 132, then the core segments 132 with the permanent magnets 40 and the rotating shaft are positioned in a prefabricated mold, and then plastic is injected to integrally connect the rotating shaft or the bearing and the core segments 132 by means of over-molding. At this time, the plastic is filled into the space between the rotation shaft and the core segments 132 and the space between the adjacent core segments 132. In other embodiments, the permanent magnet 40 and the protrusion 134 may be covered with plastic, so that the permanent magnet 40 and the corresponding core segment 132 are more firmly connected. Each core segment 132 may be provided with an axial through hole into which injected plastic flows to secure the rotor core during overmolding, as shown in fig. 6A and 6B. In other embodiments, each core segment 132 may also be axially fixed by a pin or rivet. It will be understood by those skilled in the art that the first and second side surfaces 1322, 1323 may also be curved, so long as the distance between two adjacent core segments 132 increases from the outer peripheral surface toward the axial center, and the width between two adjacent core segments 132 in the tangential direction increases from the outer peripheral surface toward the axial center. With this configuration, leakage magnetic flux between the core segments 132 can be reduced, and the torque output of the motor can be further improved.

Referring to fig. 3A and 3B, a motor 300 according to a third embodiment of the present invention is similar to the motor 100 according to the first embodiment, and is also an 8-pole 12-slot motor, and the same parts are not repeated herein. The main differences between the motor 300 of the present embodiment and the motor 100 of the first embodiment are: the permanent magnet 240 in the present embodiment is built in the rotor core 230. In other words, the motor 300 in this embodiment is an interior permanent magnet motor.

Specifically, the rotor core 230 itself in this embodiment is an annular integrated member, and a radially outer portion thereof is formed with a plurality of slots 231 axially penetrating itself. In this embodiment, 4 strip-shaped slots 231 are formed in the rotor core 230. Preferably, the 4 strip-shaped grooves 231 are uniformly distributed at intervals in the circumferential direction. Each of the slots 231 receives a permanent magnet 240 therein so that a first magnetic pole is formed by the rotor core outside the permanent magnet 240. A spacer 232 is formed between adjacent stripe-shaped grooves 231 for forming the second magnetic pole, so that the first magnetic pole and the second magnetic pole formed by the spacer 232 are alternately distributed in the circumferential direction.

Preferably, the strip groove 231 includes a straight middle groove 233 perpendicular to the radial direction, and two arc-shaped spacing grooves 234 respectively located at both ends of the middle groove 233. The permanent magnets 240 are received in the intermediate grooves 233 and are circumferentially spaced from the corresponding spacers 232 by the spacing grooves 234. Preferably, the permanent magnet 240 is rectangular, and two surfaces of the permanent magnet 240, where the length and the width are located, respectively abut against the inner radial wall 2330 and the outer radial wall 2331 of the middle slot 233. Accordingly, the radially inner wall 2330 and the radially outer wall 2331 of the middle groove 233 are preferably planar to stably fix the permanent magnet 240. Preferably, the radially inner wall 2330 and the radially outer wall 2331 of the intermediate tank 233 have a length slightly greater than the length of the permanent magnet 240 (visible in fig. 3A). The top and bottom axial surfaces 246, 247 of the permanent magnet 240 are flush with the top and bottom axial surfaces 235, 236, respectively, of the rotor core 230. In the present exemplary embodiment, the radially inner wall 2340 of the intermediate groove 234 is curved and smoothly connects the radially inner wall 2330 of the intermediate groove 233 to a preferably straight circumferential side 2320 of the respective spacer 232. Preferably, the radially outer wall of the spacing slot 234 includes two planes 2341, 2342 arranged at an angle, and the first intersection 2343 of the two planes 2341, 2342 is concave toward the radially inner wall 2340 of the spacing slot 234, and the design of the spacing slot 234 can effectively reduce the side-end leakage flux. Further, a second intersection 237 of the radially outer peripheral surface of the rotor core 230 facing the first magnetic pole and the radially outer peripheral surface of the rotor core 230 facing the second magnetic pole is recessed radially inward and preferably faces radially a first intersection 2343 of the two planes 2341, 2342, so that an uneven gap is formed between the rotor and the stator. It will be appreciated that in other embodiments, the first and second poles may be arcuate, with the outer diameter of the arcs of the first and second poles being greatest at the pole center and smallest at the pole ends.

Referring to fig. 4A and 4B, a motor 400 according to a fourth embodiment of the present invention is similar to the motor 200 according to the second embodiment, and is also an 8-pole 12-slot motor, and the rotor core 331 also includes a plurality of core segments 332 arranged at intervals along the circumferential direction, and the same parts are not repeated herein. The main differences between the motor 400 of the present embodiment and the motor 200 of the second embodiment are: the permanent magnet 343 in this embodiment is built in the rotor core 331 and is arranged in the radial direction of the motor. In other words, the motor 400 in this embodiment is an interior permanent magnet motor.

Specifically, in the present embodiment, the rotor core 331 is annular as a whole and includes 4 sets of core segments 332 uniformly spaced in the circumferential direction. Each set of core segments 332 comprises two separate sub-segments 3326, a strip-shaped permanent magnet 343 is arranged between the two sub-segments 3326, and the permanent magnet 343 is arranged with its length direction parallel to the radial direction of the rotor core 331, the permanent magnet 343 being magnetized in a direction perpendicular to the radial direction such that the outer circumferential surfaces of the sub-segments 3326 on both sides of the permanent magnet 343 have different polarities. According to the above configuration, the 8-pole motor is configured using only 4 permanent magnets, so the number of permanent magnets used can be reduced, reducing the cost.

In this embodiment, the two subsections 3326 of each set of core segments 332 are symmetrical in the radial direction of the machine. Each sub-section 3326 is generally triangular in shape with a first side 3320 spaced from and extending radially of another sub-section 3326 of the same set of core sections 332, a second side 3322 opposite a sub-section 3326 of an adjacent set of core sections 332, and a third side 3321, a radially outer side 3321, connecting the first side 3320 and the second side 3322. The permanent magnets 343 are arranged between the two first sides 3320 of the two sub-sections 3326 of each set of core sections 332. Preferably, the outer peripheral side 3321 of each sub-section 3326 includes a central protrusion 334 and radially inwardly recessed grooves 333 formed on both sides of the protrusion 334. In this embodiment, the outer peripheral side of the projection 334 is arc-shaped. Each groove 333 extends axially through the sub-section 3326 and circumferentially through to the respective first side 3320 or second side 3322. The bottom wall of the groove 333 is planar, and the side wall of the groove 333 is perpendicular to the bottom wall of the groove 333. In this embodiment, the second side 3322 of each sub-segment and the second side 3322 of a sub-segment 3326 of the adjacent set of core segments 332 are symmetrical with respect to the radial direction of the motor, and the distance between two adjacent sets of core segments 332 gradually increases from the outer peripheral surface radially inward to reduce the magnetic flux leakage between the core segments 332, thereby improving the torque output of the motor.

In this embodiment, the permanent magnet 343 has a rectangular parallelepiped shape and contacts or abuts against the first sides 3320 of the two sub-sections 3326. Preferably, the radially inner side 3430 and the radially outer side 3431 of the permanent magnet 343 are flush with the inner peripheral side of the core segment 332 and the bottom wall of the groove 333, respectively, and the axially upper face 3432 and the axially lower face 3433 of the permanent magnet 343 are flush with the axially upper face 3324 and the axially lower face 3325 of the core segment 332, respectively. It will be appreciated that in other embodiments, the permanent magnets 343 may be arranged in other configurations and/or arrangements within the core segments, and accordingly, the core segments will also be adapted.

During assembly, the sets of core segments 332 with the permanent magnets 343 and the shaft or bearing are positioned in a pre-fabricated mold, and plastic is injected to integrally connect the shaft and the core segments 332 by over-molding. At this time, the plastic is filled into the space between the rotation shaft and the core segment 332 and the space between the adjacent core segments 332. Plastic can also be filled around the outer circumference of the core segments 332 to make the permanent magnets 343 and the corresponding core segments 332 more securely connected.

Referring to fig. 5A and 5B, a motor 500 according to a fifth embodiment of the present invention is similar to the motor 100 according to the first embodiment, and is also a surface-mount permanent magnet motor, and the rotor core 430 itself is an annular integrated member, and the details of the same parts are not repeated herein. The main differences between the motor 500 of the present embodiment and the motor 100 of the first embodiment are: the motor in this embodiment is a 10 pole, 12 slot motor.

Specifically, the rotor in the present embodiment includes 5 bar-shaped permanent magnets 440. Accordingly, the outer circumferential side of the rotor core 430 is formed with 5 mounting parts 435 for fixing the permanent magnets 440, 5 protrusions 434 for forming the second magnetic pole, and 10 recesses 433 formed between the adjacent mounting parts 435 and protrusions 434. The 5 permanent magnets 440 are fixed to the respective mounting portions 435 and are circumferentially alternated one by one with the 5 protrusions 434, thereby forming 10 magnetic poles circumferentially alternated. In other words, the number of pole pairs of the rotor in the present embodiment is 5.

Referring to fig. 6A and 6B, a motor 600 according to a sixth embodiment of the present invention is similar to the motor 200 according to the second embodiment, and is also a surface-mounted permanent magnet motor, and the rotor core 530 itself also adopts a segmented core structure, and the same parts are not described again. The main differences between the motor 600 of the present embodiment and the motor 200 of the second embodiment are: the motor 600 in this embodiment is a 10 pole, 12 slot motor.

Specifically, the rotor in the present embodiment includes 5 bar-shaped permanent magnets 540. Accordingly, the rotor core 530 includes 5 circumferentially spaced core segments 532. The outer peripheral side 5321 of each core segment 532 forms a mounting portion 535 for fixing the permanent magnet 540 and a projection 534 for forming the second magnetic pole, and a groove 533 formed between the mounting portion 535 and the projection 534. The 5 permanent magnets 540 are fixed to the corresponding mounting portions 535, and are circumferentially alternated with the 5 protrusions 534 one by one, so that 10 magnetic poles are formed, which are circumferentially alternated, in other words, the number of pole pairs of the rotor in this embodiment is 5.

Further, in the present embodiment, the radially inner portion of each core segment 532 is formed with a through hole 5326 that extends axially therethrough. Preferably, the radially inner portion of each core segment 532 is formed with two of the through holes 5326. One of the two through holes 5326 is adjacent to the first side of the core segment 532 and the other is adjacent to the second side of the core segment 532. During overmolding, the injected plastic flows into the axial through hole 5326 to fix the rotor core 530. In other embodiments, each core segment 532 may be axially fixed through a through hole by a pin or rivet.

Referring to fig. 7A and 7B, a motor 700 according to a seventh embodiment of the present invention is similar to the motor 300 according to the third embodiment, and is also an interior permanent magnet motor, and the rotor core 630 itself is an annular integrated member, and the details of the same parts are not repeated herein. The main differences between the motor 700 of the present embodiment and the motor 300 of the third embodiment are: the motor 700 in this embodiment is a 10 pole, 12 slot motor.

Specifically, the rotor in the present embodiment includes 5 rectangular parallelepiped permanent magnets 640. Accordingly, the radially outer portion of the rotor core 630 is formed with 5 bar-shaped grooves 631 penetrating itself in the axial direction. The 5 strip-shaped grooves 631 are uniformly distributed at intervals in the circumferential direction. A spacer 632 is formed between the adjacent slots 631 to form a second magnetic pole. In this embodiment, each of the grooves 631 includes a straight middle groove 633 perpendicular to a radial direction, and two spaced grooves 634 respectively communicating with both ends of the middle groove 633 at an angle. The permanent magnets 640 are accommodated in the intermediate grooves 633 and are circumferentially spaced from the corresponding spacer portions 632 by one of the spacer grooves 634. Preferably, the length of the permanent magnet 640 is equal to the length of the radially inner and outer walls of the intermediate groove 633. Preferably, the radially inner wall of the middle groove 633 is recessed to form a recess 6330, and the radially inner side of the permanent magnet 640 is accommodated in the recess 6330, so that the sidewall of the recess 6330 can limit the position of the permanent magnet 640. The radial width of the spacer groove 634 is greater than that of the intermediate groove 633.

Referring to fig. 8A and 8B, a motor 800 according to an eighth embodiment of the present invention is similar to the motor 400 according to the fourth embodiment, and is also an interior permanent magnet motor, and the rotor core 730 itself also adopts a segmented core structure, and the details of the same parts are not repeated herein. The main differences between the motor 800 of the present embodiment and the motor 400 of the fourth embodiment are: the motor 800 in this embodiment is a 10 pole, 12 slot motor.

Specifically, the rotor in the present embodiment includes 5 rectangular parallelepiped permanent magnets 740. Accordingly, rotor core 730 includes 5 sets of circumferentially spaced apart core segments 732. Each set of core segments 732 includes two sub-segments 7326 that are symmetric in the radial direction of the motor. A strip-shaped permanent magnet 740 is disposed between the two sub-sections 7326, and the permanent magnet 740 is magnetized in a vertical radial direction. Unlike the fourth embodiment, in the present embodiment, the outer circumferential side 7321 of each sub-section 7326 forms a groove 733 only at one end thereof near the first side. The second side of each sub-section 7326 is preferably further formed with a protruding pillar 7327 to facilitate the arrangement of the through hole 7323, so that the second side of each sub-section 7326 has a curved shape. In this embodiment, the distance between adjacent sets of core segments 732 gradually increases from the outer circumferential surface radially inward, and gradually decreases and then gradually increases at the protruding columns 7327 to the radially inner side of the core segments 732. Preferably, the radially inner side 7430 and the radially outer side 7431 of the permanent magnet 740 are flush with the radially inner side 7320 of the core section 732 and the bottom wall of the groove 733, respectively. In this embodiment, the axial bottom surface 7432 of the permanent magnet 740 is flush with the axial bottom surface 7324 of the core section 732, and the axial top surface 7433 of the permanent magnet 740 is lower than the axial top surface 7325 of the core section 732.

In addition, in the present embodiment, a through hole 7323 is formed in each of the two sub-sections 7326 of each set of core sections 732. Preferably, the through hole 7323 is located at a corresponding center position of the convex pillar 7327, so as to improve the strength of each sub-section 7326. More preferably, the through-hole 7323 is located adjacent to the radially inner side 7320 of the core section 732 relative to the groove 733. During overmolding, the injected plastic flows into axial through-hole 7326 to secure rotor core 730.

Referring to fig. 9A and 9B, a motor 900 according to a ninth embodiment of the present invention is similar to the motor 200 according to the second embodiment, and is also a surface-mounted permanent magnet motor, and the rotor core 830 itself also adopts a segmented core structure, and the same parts are not described again. The main differences between the motor 900 of the present embodiment and the motor 200 of the second embodiment are: the motor 900 in this embodiment is a 14 pole, 12 slot motor.

Specifically, the rotor in the present embodiment includes 7 bar-shaped permanent magnets 840. Accordingly, rotor core 830 includes 7 circumferentially spaced apart core segments 832. The outer peripheral side of each core segment 832 forms a mounting portion 835 for fixing the permanent magnet 840 and a protrusion 834 for forming the second magnetic pole, and a groove 833 formed between the mounting portion 835 and the protrusion 834. The 7 permanent magnets 840 are fixed to the corresponding mounting portions 835, and are circumferentially alternated with the 7 protrusions 834 to form 14 magnetic poles circumferentially alternated. In other words, the number of pole pairs of the rotor of the motor in the present embodiment is 7.

It will be appreciated that the above embodiments are not exhaustive. The various features of the embodiments may be combined without technical conflict or conflict.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-listed embodiments, and any simple changes or equivalent substitutions of technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are within the protection scope of the present invention.

Claims (11)

1. An electric machine rotor comprises a rotor core and permanent magnets fixed in the rotor core, and is characterized in that the rotor core comprises a plurality of groups of core sections which are arranged at intervals along the circumferential direction, each group of core sections comprises two independent subsections, and the permanent magnets extending along the radial direction are arranged between the two subsections.

2. An electric machine rotor according to claim 1, characterized in that the permanent magnets are magnetized in a direction perpendicular to the radial direction of the rotor core so that the outer circumferential surfaces of the sub-sections on both sides of the permanent magnets have different polarities.

3. An electric machine rotor as recited in claim 2, wherein the two sub-sections of each set of core sections are symmetrical with respect to a radial direction of the rotor core, each sub-section is generally triangular, and a side of one of the two sub-sections opposite the other of the two sub-sections extends in the radial direction of the rotor core.

4. The electric machine rotor as recited in claim 2, wherein a distance between adjacent two of the core segments increases gradually from an outer circumferential surface of the rotor core toward an axial center of the rotor core.

5. An electric machine rotor as recited in claim 2, wherein a shape of a gap between two adjacent sets of the core segments is different from a shape of a gap between two of the subsections of each set of core segments.

6. An electric machine rotor as recited in claim 1, wherein the circumferentially opposite sides of the core segments are inclined at the same angle relative to a radial direction of the rotor core.

7. The electric machine rotor as recited in claim 1, further comprising a shaft or a bearing extending through the rotor core, wherein the shaft or the bearing and the rotor core are integrally connected by overmolding with plastic.

8. The electric machine rotor as recited in claim 1, wherein the outer peripheral side of each sub-segment includes a projection in the middle and a radially inwardly recessed groove formed on both sides of the projection, and the radially inner side and the radially outer side of the permanent magnet are flush with the inner peripheral side of the core segment and the bottom wall of the groove, respectively.

9. An electric machine comprising a stator and an electric machine rotor according to any of claims 1-8.

10. The electric machine of claim 9, wherein the stator comprises a plurality of teeth and a three-phase winding wound around the plurality of teeth, and each phase winding comprises at least two windings wound around different teeth connected in series.

11. The machine of claim 9 wherein there is a non-uniform air gap between the stator and the rotor.

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