Rotor core, rotor assembly and motor

Abstract

The utility model belongs to the technical field of motor manufacturing, and particularly relates to a rotor core, a rotor assembly and a motor, the rotor core comprises a plurality of core segments which are laminated along the axial direction, each core segment comprises a plurality of laminated punching sheet groups, each layer of punching sheet group comprises a plurality of rotor punching sheets which are laminated along the axial direction, and the rotor punching sheets are laminated along the axial direction. Each rotor punching sheet is provided with a plurality of magnetic poles along the circumferential direction; each magnetic pole is provided with at least one layer of magnetic steel groove group along the radial direction, each layer of magnetic steel groove group comprises at least one magnetic steel groove, the magnetic steel grooves of part of the magnetic poles on each rotor punching sheet are internally provided with limiting shoulders which protrude out of the groove walls to limit the magnetic steel, and the number of part of the magnetic poles is greater than or equal to one and less than the total number of the magnetic poles. And each layer of punching sheet group of each iron core section relatively rotates by a magnetic pole angle, so that a limiting stop shoulder is arranged in a magnetic steel groove of each magnetic pole in each iron core section. According to the utility model, the number of the limiting shoulders of the whole rotor iron core is reduced, so that the shoulder leakage flux is reduced, and the electromagnetic performance is improved.

Description

Technical Field

[0001] This utility model belongs to the field of motor manufacturing technology, and in particular relates to a rotor core, rotor assembly and motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) hold a pivotal position in the new energy vehicle sector due to their significant advantages such as high efficiency and high power density. Currently, the mainstream PSM rotor topologies on the market are diverse, including single-V, V-type, double-V, and triple-V designs. These structures have demonstrated good stability and reliability in long-term applications.

[0003] In rotor structures, magnet shoulders are often placed in the magnet slots to create limiting intervals for each section of magnet. However, the presence of magnet shoulders inevitably leads to magnetic leakage, thereby reducing motor performance. This is especially true for rotor structures with a large number of magnet shoulders, where the size of the magnet shoulders has an increasingly significant impact on the motor's output performance. However, due to limitations in current technology and manufacturing processes, the industry's optimization of magnet shoulders has reached a bottleneck. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a rotor core, rotor assembly and motor to solve the technical problem that the motor performance is reduced due to the large number of limiting shoulders in the rotor core in the prior art.

[0005] To achieve the above and other related objectives, the technical solution of this utility model is as follows:

[0006] A rotor core, comprising:

[0007] Multiple core segments are stacked along the axial direction, each core segment includes multiple layers of stacked laminations, each lamination includes multiple rotor laminations stacked along the axial direction, and each rotor lamination has multiple magnetic poles along the circumferential direction;

[0008] Each of the magnetic poles has at least one layer of magnetic slots arranged radially, and each layer of magnetic slots includes at least one magnetic slot. In the magnetic slots of some of the magnetic poles on each rotor lamination, there are limiting shoulders protruding outward from the slot wall to limit the magnetics. The number of the partial magnetic poles is greater than or equal to one and less than the total number of magnetic poles. The laminations of each core segment are rotated relative to each other by a magnetic pole angle so that the magnetic slots of each magnetic pole in each core segment are provided with limiting shoulders.

[0009] Optionally, the number of lamination groups in each core segment is the same as the number of magnetic poles, the length of each lamination group in each core segment along the axial direction is the same, and the length of the limiting shoulder corresponding to each magnetic pole in each core segment along the axial direction is the same.

[0010] Optionally, each of the magnet slots has two opposing slot walls, and the limiting shoulder is disposed on at least one of the slot walls, and the limiting shoulder is used to be disposed between adjacent magnets, or between the ends of the magnets and the magnet slots.

[0011] Optionally, multiple limiting shoulders are provided in the corresponding magnet groove and are distributed at intervals along the extension direction of the two side walls of the magnet groove that are arranged opposite to each other.

[0012] Optionally, the limiting shoulder is located on the side wall of the magnet slot near the center of the rotor core.

[0013] Optionally, the limiting shoulder includes a main body protruding from the groove wall and two opposing first and second sidewalls disposed on the main body, and the top end face of the protrusion is an arc surface or a plane, and the first and second sidewalls are respectively used to abut against two adjacent magnets.

[0014] Optionally, when the front and back structures of the rotor laminations are the same, in each magnetic slot group of the partial magnetic poles on each rotor lamination, the magnetic slot located on the same side of the direct shaft is provided with the limiting shoulder.

[0015] Optionally, the magnet slot group is configured as one, two, or three layers from the outside to the inside along the radial direction of the rotor core. Each layer of the magnet slot group includes at least two magnet slots symmetrically arranged about the direct axis. The two magnet slots have a V-shaped structure or an arc-shaped structure. Each magnet slot is used to accommodate one or more magnet segments.

[0016] Based on the same concept, this utility model also provides a rotor assembly, including a magnet and a rotor core as described above, wherein the magnet is installed in the magnet slot of the rotor core.

[0017] Based on the same concept, this utility model also provides an electric motor, including a stator assembly and a rotor assembly, wherein the rotor assembly is the rotor assembly as described above.

[0018] As described above, the present invention has the following beneficial effects:

[0019] By setting limiting shoulders in the magnet slots of some magnetic poles on each rotor lamination, with the number of some magnetic poles being greater than or equal to one and less than the total number of magnetic poles, and by rotating the lamination groups of each layer of each core segment relative to each other by a magnetic pole angle, limiting shoulders are set in the magnet slots of each magnetic pole in each core segment. This ensures that each magnet in each core segment is limited by a limiting shoulder, achieving the effect of evenly distributing limiting shoulders on each pole of the rotor core, reducing the overall number of limiting shoulders, thereby reducing shoulder leakage magnetic flux and improving electromagnetic performance. Attached Figure Description

[0020] Figure 1 A schematic diagram of the stacked structure of some lamination groups in the rotor core of this utility model embodiment;

[0021] Figure 2 An exploded structural diagram of a portion of the lamination assembly in the rotor core of this utility model embodiment;

[0022] Figure 3 This is a schematic diagram of the structure of a single rotor lamination according to an embodiment of the present invention;

[0023] Figure 4 for Figure 3 Schematic diagram of the magnetic pole structure of the rotor lamination with limiting shoulder (equipped with magnets);

[0024] Figure 5 This is an enlarged structural schematic diagram of the limiting shoulder according to an embodiment of the present utility model;

[0025] Figure 6 A schematic diagram of the structure of a full-shoulder rotor lamination;

[0026] Figure 7 This is a comparison diagram of the external characteristic torque of the rotor core and the full-shoulder rotor core in the embodiments of this utility model;

[0027] Figure 8 This is a comparison diagram of the external characteristic power of the rotor core and the full-shoulder rotor core in the embodiments of this utility model.

[0028] Explanation of reference numerals in the attached figures

[0029] 100-Panning Set;

[0030] 10-Rotor laminations;

[0031] 11-Magnetic steel trough assembly; 12-Magnetic isolation bridge; 13-Limiting shoulder; 131-Main body; 132-First side wall; 133-Second side wall;

[0032] 20-Magnetic steel;

[0033] 10a - Full-shoulder rotor lamination; 11a - Magnet slot assembly; 13a - Limiting shoulder. Detailed Implementation

[0034] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0035] It should be noted that the illustrations provided in this embodiment are merely schematic representations of the basic concept of this utility model. Therefore, the illustrations only show components relevant to this utility model and are not drawn according to the actual number, shape, and size of the components in implementation. In actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the component layout may be more complex. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to assist those skilled in the art in understanding and reading the content disclosed in the specification. They are not intended to limit the implementation conditions of this utility model and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this utility model, should still fall within the scope of the technical content disclosed in this utility model. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in this specification are only for clarity of description and are not intended to limit the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered as within the scope of implementation of this utility model.

[0036] In order to describe this utility model in detail, the following is a specific description of a rotor core of this utility model:

[0037] Please combine Figure 1 and Figure 2 As shown, this utility model provides a rotor core, comprising: multiple core segments stacked along the axial direction, each core segment including multiple layers of lamination groups 100, each lamination group 100 including multiple rotor laminations 10 stacked along the axial direction, each rotor lamination 10 having multiple magnetic poles arranged circumferentially; each magnetic pole having at least one layer of magnetic slot group 11 arranged radially, each magnetic slot group 11 including at least one magnetic slot, each rotor lamination 10 having a limiting shoulder 13 protruding outward from the slot wall in the magnetic slot of a portion of the magnetic poles to limit the magnetic steel 20, the number of partial magnetic poles being greater than or equal to one and less than the total number of magnetic poles, each lamination group 100 of each core segment being rotated relative to each other by a magnetic pole angle, so that each magnetic pole in each core segment has a limiting shoulder 13 in the magnetic slot.

[0038] Specifically, the rotor core comprises multiple core segments along the axial direction, with a torsion angle between each core segment. Each core segment includes multiple lamination groups 100 stacked axially. Figure 1 The diagram shows a schematic of the stacked structure of two lamination groups 100 in one core segment. Figure 2It can be seen that the adjacent lamination groups 100 are rotated relative to each other by a magnetic pole angle, so that each magnet 20 of each magnetic pole is limited by a limiting shoulder 13. The magnet slot group 11 provided on each rotor lamination 10 of each lamination group 100 provides space for the installation of the magnet 20. In this example, see [reference]. Figure 3 and Figure 4 Each rotor lamination 10 has three layers of magnetic slots 11 arranged radially on each magnetic pole, namely the first layer, the second layer, and the third layer, from the outer edge to the inner edge. By rationally setting the number and structure of the magnetic slots 11, the installation position and orientation of the magnets 20 can be optimized, improving the utilization rate of the magnets 20 and enhancing the strength and stability of the magnetic field. In this example, each layer of magnetic slots 11 includes two magnetic slots symmetrically arranged about the direct axis, and a magnetic isolation bridge 12 is provided between the two magnetic slots. The arrangement of multiple magnetic slots can increase the number of magnets 20 installed, improving the magnetic flux density and torque output capability of the motor. At the same time, the rational layout of the magnetic slots can optimize the distribution of the magnetic field, reduce magnetic field leakage and loss, and improve the efficiency of the motor.

[0039] The limiting shoulder 13 effectively limits and fixes the magnet 20, preventing it from shaking or shifting during motor operation and ensuring a tight fit between the magnet 20 and the magnet slot. Setting the limiting shoulder 13 only in the magnet slots of some poles reduces the impact on the magnetic field of other poles, maintaining the uniformity and stability of the motor's magnetic field. It is understood that the number of partial poles is greater than or equal to one and less than the total number of poles. For example, for an 8-pole motor with a total of 8 poles, the number of partial poles can be greater than or equal to one and less than 8, such as 1, 2, 3, 4, 5, 6, or 7.

[0040] See Figure 3 In this example, taking the case where the limiting shoulders 13 on each rotor lamination 10 are concentrated on one magnetic pole, then each lamination group 100 has only one magnetic pole with a limiting shoulder 13. (See also...) Figure 2 As shown, by concentrating the limiting shoulders 13 of the magnet slot on a magnetic pole, and rotating the laminations 100 relative to each other by a magnetic pole angle, each magnet 20 in each core segment is limited by the limiting shoulders 13, thereby achieving the purpose of limiting the magnet 20 in each core segment and reducing the overall number of limiting shoulders 13, thereby reducing shoulder leakage and improving electromagnetic performance.

[0041] Through the aforementioned relative rotation structure, the effect of having limiting shoulders 13 within the magnet slots of each magnetic pole in each core segment is achieved. This ensures the stable installation and limiting of the magnets 20, while also optimizing the magnetic field distribution and mechanical structure of the rotor core. The reasonable placement of the limiting shoulders 13 reduces magnetic leakage of the magnets 20, improving motor efficiency; simultaneously, the staggered layout of the lamination groups 100 enhances the rotor's mechanical properties and magnetic field uniformity.

[0042] Understandably, the number of lamination groups 100 in each core segment is the same as the number of magnetic poles, the axial length of each layer of lamination groups 100 in each core segment is the same, and the axial length of the limiting shoulders 13 corresponding to each magnetic pole in each core segment is the same. Specifically, the number of lamination groups 100 in each core segment is the same as the number of magnetic poles to ensure the symmetry and balance of the magnetic circuit, making the magnetic field distribution uniform and improving motor performance; optimizing the magnetic pole spacing, reducing magnetic field distortion, and improving magnetic circuit efficiency; and ensuring consistent structural strength distribution, enhancing rotor reliability. The axial length of each layer of lamination groups 100 in each core segment is the same, which helps maintain the consistency of the lamination groups 100 during stacking, improving stacking accuracy; and enhancing the core bonding strength, reducing motor temperature rise and noise. The limiting shoulders 13 corresponding to each magnetic pole of each core segment have the same axial length. The limiting shoulders 13 of the same length can uniformly limit and fix the magnet 20, reduce the shaking and displacement of the magnet 20 during motor operation, ensure the tight fit between the magnet 20 and the magnet slot, and improve the utilization rate of the magnet 20. It also reduces the gap between the magnet 20 and the slot wall, which helps to reduce the magnetic leakage phenomenon of the magnet 20. Since the fixing effect of the limiting shoulders 13 on the magnet 20 is uniform and consistent, the magnetic field of the rotor remains stable during operation.

[0043] Taking an 8-pole motor as an example, each core segment has 8 layers of laminations 100. To ensure no additional unbalanced electromagnetic force is generated, the axial length of each layer of laminations 100 in each core segment is the same, and the length of the corresponding limiting shoulders 13 in each magnetic pole of the overall rotor core is also the same. That is, the axial length len of each layer of laminations 100 in each core segment is:

[0044]

[0045] Where lenR is the total length of the rotor core, slice is the number of core segments, and p is the number of pole pairs of the motor. For example, for an 8-pole motor, p is 4 pairs.

[0046] The angle ang of rotation between each lamination group 100 in each core segment is:

[0047]

[0048] Taking an 8-pole motor as an example, the rotation angle between each layer of laminations in each core segment is 360 / (2×4)=45°.

[0049] See Figure 4 and Figure 5 In some embodiments, each magnet slot has two opposing slot walls, and a limiting shoulder 13 is disposed on at least one slot wall. The limiting shoulder 13 is used to be disposed between adjacent magnets 20, or between the ends of magnets 20 and magnet slots. Specifically, the two opposing slot walls provide stable support and fixation for the magnets 20. The slot walls, as boundaries of the magnetic field, guide the distribution and direction of the magnetic field. The limiting shoulder 13, disposed on the slot wall, limits the magnets 20, preventing them from shifting due to vibration or centrifugal force during motor operation, ensuring a tight fit between the magnets 20 and the magnet slot. The design of the limiting shoulder 13 makes the assembly of magnets 20 simpler and faster. Through the guiding and fixing effect of the limiting shoulder 13, magnets 20 can be accurately installed, improving assembly efficiency and product quality. Preferably, the limiting shoulder 13 is disposed on the slot wall of the magnet slot near the center of the rotor core.

[0050] By setting the limiting shoulder 13 between adjacent magnets 20, the multiple sections of magnets 20 in the magnet slot are limited, thereby optimizing the magnetic field distribution and reducing interference between magnetic fields. By setting the limiting shoulder 13 between the ends of the magnets 20 and the magnet slot, the fixing effect of the magnets 20 at the ends can be enhanced, effectively preventing the magnets 20 from falling off or shifting at the ends due to vibration or centrifugal force, thus improving the safety and reliability of the motor.

[0051] Understandably, multiple limiting shoulders 13 are provided in the corresponding magnet slots and are spaced apart along the extension direction of the two opposite sides of the magnet slot. Specifically, by providing multiple limiting shoulders 13, multiple points of the magnet 20 located in the magnet slot can be limited, effectively preventing the magnet 20 from shifting or falling off due to vibration or centrifugal force during motor operation, thus improving the installation stability and reliability of the magnet 20. Furthermore, from the outer edge of the rotor core towards the center of the rotor core, the number of limiting shoulders 13 gradually increases with the increase of the number of magnet 20 segments. In this embodiment, each magnet slot in the first layer of magnet slots is provided with 2 limiting shoulders 13, each magnet slot in the second layer of magnet slots is provided with 5 limiting shoulders 13, and each magnet slot in the third layer of magnet slots is provided with 6 limiting shoulders 13.

[0052] Continue reading Figure 5In the above embodiment, the limiting shoulder 13 is located on the side wall of the magnet slot near the center of the rotor core. Specifically, the limiting shoulder 13 being located on the side wall of the magnet slot near the center of the rotor core helps to optimize the distribution of the magnetic field, making the magnetic field more concentrated and stable, thereby improving the output torque and efficiency of the motor; it also enhances the structural strength of the magnet slot, enabling it to resist the centrifugal force generated by the magnet 20 during high-speed operation and preventing deformation or damage to the magnet slot.

[0053] The limiting shoulder 13 includes a main body 131 protruding from the groove wall and two opposing first sidewalls 132 and second sidewalls 133 disposed on the main body 131. The top end face of the protrusion is an arc surface or a plane. The first sidewalls 132 and second sidewalls 133 are respectively used to abut against two adjacent magnets 20. Specifically, the limiting shoulder 13, relying on the first sidewalls 132 and second sidewalls 133 of its main body 131, can limit the magnets 20 at multiple points, preventing the magnets 20 from shifting or falling off during motor operation, improving the installation stability of the magnets 20, ensuring close contact between the magnets 20, and reducing magnetic leakage. The top end face of the protrusion is an arc surface or a plane, which reduces stress concentration between the magnets 20 and the limiting shoulder 13, preventing the magnets 20 from being damaged due to excessive local stress.

[0054] It should be noted that when the front and back structures of the rotor laminations 10 are identical, in each magnetic slot group 11 of the upper magnetic poles of each rotor lamination 10, the magnetic slots located on the same side of the direct shaft are provided with limiting shoulders 13. Specifically, for rotor laminations 10 with identical front and back structures, limiting shoulders 13 can be provided in some magnetic poles (e.g., one) for the magnetic slots located on the same side of the direct shaft. In each lamination group 100 of each core segment, half of the rotor laminations 10 are stacked using the front structure, and the other half are stacked using the back structure. By rotating each lamination group 100 by one magnetic pole angle, the limiting shoulders 13 of all magnetic poles can still be evenly distributed to meet the limiting requirements of the magnets 20 through the operation of rotating the lamination group 100 and flipping the rotor laminations 10. This reduces the number of limiting shoulders 13 by half and further reduces the performance loss caused by the shoulders.

[0055] Understandably, the magnet slot group 11 is arranged in one, two, or three layers from the outside to the inside along the radial direction of the rotor core. Each layer of the magnet slot group 11 includes at least two magnet slots symmetrically arranged about the direct axis. The two magnet slots have a V-shaped or arc-shaped structure, and each magnet slot is used to accommodate one or more sections of magnet 20. Specifically, the arrangement of the magnet slot group 11 on the rotor lamination 10 can be a single-layer, two-layer, or three-layer magnet slot group 11, etc. Setting multiple layers of magnet slot groups 11 from the outside to the inside along the radial direction helps to optimize the magnetic field distribution, making the magnetic field more concentrated and stable, and improving the output torque and efficiency of the motor. The two magnet slots in each layer of the magnet slot group 11 form a V-shaped or arc-shaped structure symmetrical about the direct axis. The magnet slots symmetrically arranged about the direct axis help to balance the magnetic field, reduce magnetic field distortion and local magnetic saturation, and improve the utilization rate of the magnetic field. The V-shaped or arc-shaped structure of the magnet slots optimizes the magnetic field path, making the magnetic field more concentrated and stable. Each magnet slot contains a single or multiple magnets 20, which can be configured according to the performance requirements of the motor. The design of multiple magnets 20 helps to reduce eddy current losses and improve the efficiency of the motor.

[0056] In addition, the rotor core of this utility model can have multiple poles, such as 6 poles, 8 poles, 10 poles, etc., and there is no specific limitation.

[0057] Figure 3 This is a rotor lamination structure according to an embodiment of the present invention. It is a three-layer C-shaped rotor lamination 10 of an 8-pole motor, and the limiting shoulder 13 is located on the same magnetic pole. Each pole of the rotor lamination 10 is provided with three layers of magnetic steel slot groups 11. The rotor core composed of this type of rotor lamination 10 (referred to as single-pole shoulder rotor lamination) is referred to as single-pole shoulder rotor core. That is, the limiting shoulder 13 is only set on a certain magnetic pole. Each core segment is composed of 8 layers of lamination groups 100 in the axial direction. The length of each lamination group 100 is the same. Each lamination group 100 rotates 45° of magnetic pole angle in sequence. Only one-eighth of the limiting shoulder 13 is used to achieve the limiting effect on the entire rotor magnet 20. Figure 6 This is a structure of a full-shoulder rotor lamination 10a, which is also a three-layer C-shaped rotor lamination of an 8-pole motor. The limiting shoulders 13a are located on all magnetic poles. Each pole of the full-shoulder rotor lamination 10a is provided with three layers of magnet slot groups 11a, and each layer of magnet slot group 11a is roughly C-shaped. Multiple magnet segments 20a can be set in each layer of magnet slot group 11a. The rotor core constructed with this type of full-shoulder rotor lamination 10a is simply referred to as a full-shoulder rotor core, that is, each pole has the limiting shoulders 13a required for all magnets 20a, and the poles are circumferentially symmetrical. The total number of limiting shoulders 13a in the full-shoulder rotor core is 8 times the number of limiting shoulders 13a in a single-pole shoulder rotor core.

[0058] The following are the performance parameters of the full-shoulder rotor core and the single-shoulder rotor core under the same simulation boundary, as compared by testing: The peak torque of the full-shoulder rotor core is 413.6 Nm, the peak power is 224.5 kW, and the maximum power at high speed is 182.8 kW; the peak torque of the single-shoulder rotor core is 418.7 Nm, the peak power is 228.6 kW, and the maximum power at high speed is 187.5 kW. Figure 7 and Figure 8 As shown, after reducing the number of limiting shoulders, the external characteristic torque curve of the single-pole shoulder rotor core is generally higher than that of the traditional full-shoulder rotor core. In terms of optimization effect, compared with the full-shoulder rotor core, the single-pole shoulder rotor core increases the peak torque in the base speed region by 1.23%, the peak power by 1.83%, and the maximum speed power at the maximum speed of 20,000 rpm by 2.57%. It can be seen that the external characteristic performance of the single-pole shoulder rotor core proposed in this invention is generally superior to that of the traditional full-shoulder rotor core.

[0059] Based on the same concept, this utility model also provides a rotor assembly, including a magnet 20 and a rotor core as described above, wherein the magnet 20 is installed in the magnet slot of the rotor core.

[0060] Based on the same concept, this utility model also provides an electric motor, including a stator assembly and a rotor assembly, wherein the rotor assembly is the rotor assembly as described above.

[0061] In summary, the rotor core, rotor assembly, and motor provided by this utility model feature limiting shoulders 13 in the magnetic slots of some magnetic poles on each rotor lamination 10. The number of some magnetic poles is greater than or equal to one and less than the total number of magnetic poles. Furthermore, the lamination groups 100 of each core segment are rotated relative to each other by a magnetic pole angle. This ensures that each magnetic pole in each core segment has a limiting shoulder 13 in its magnetic slot, thereby limiting each magnet 20 in each core segment. This achieves the effect of evenly distributing limiting shoulders 13 across all poles of the rotor core, reducing the overall number of limiting shoulders 13, and thus reducing shoulder leakage magnetic flux and improving electromagnetic performance.

[0062] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A rotor core, characterized in that, include: Multiple core segments are stacked along the axial direction, each core segment includes multiple layers of stacked laminations, each lamination includes multiple rotor laminations stacked along the axial direction, and each rotor lamination has multiple magnetic poles along the circumferential direction; Each of the magnetic poles has at least one layer of magnetic slots arranged radially, and each layer of magnetic slots includes at least one magnetic slot. In the magnetic slots of some of the magnetic poles on each rotor lamination, there are limiting shoulders protruding outward from the slot wall to limit the magnetics. The number of the partial magnetic poles is greater than or equal to one and less than the total number of magnetic poles. The laminations of each core segment are rotated relative to each other by a magnetic pole angle so that the magnetic slots of each magnetic pole in each core segment are provided with limiting shoulders.

2. A rotor core according to claim 1, characterized in that, The number of lamination groups in each core segment is the same as the number of magnetic poles. The lamination groups in each core segment have the same axial length, and the limiting shoulders corresponding to each magnetic pole in each core segment have the same axial length.

3. A rotor core according to claim 1 or 2, characterized in that, Each of the magnet slots has two opposing slot walls, and the limiting shoulder is disposed on at least one of the slot walls. The limiting shoulder is used to be disposed between adjacent magnets or between the ends of the magnets and the magnet slots.

4. A rotor core according to claim 3, characterized in that, Multiple limiting shoulders are provided in the corresponding magnet grooves and are distributed at intervals along the extension direction of the two opposite sides of the magnet groove.

5. A rotor core according to claim 3, characterized in that, The limiting shoulder is located on the side wall of the magnet slot near the center of the rotor core.

6. A rotor core according to claim 3, characterized in that, The limiting shoulder includes a main body protruding from the groove wall and two opposing first and second sidewalls disposed on the main body. The top end face of the protrusion is an arc surface or a plane. The first and second sidewalls are respectively used to abut against two adjacent magnets.

7. A rotor core according to claim 1, characterized in that, When the front and back structures of the rotor laminations are the same, in each magnetic slot group of the partial magnetic poles on each rotor lamination, the magnetic slot located on the same side of the direct shaft is provided with the limiting shoulder.

8. A rotor core according to claim 1, characterized in that, The magnet slot assembly is arranged in one, two, or three layers from the outside to the inside along the radial direction of the rotor core. Each layer of the magnet slot assembly includes at least two magnet slots arranged symmetrically about the direct axis. The two magnet slots have a V-shaped structure or an arc-shaped structure. Each magnet slot is used to accommodate one or more magnet segments.

9. A rotor assembly, characterized in that, It includes magnets and a rotor core as described in any one of claims 1-8, wherein the magnets are installed in magnet slots in the rotor core.

10. An electric motor, characterized in that, It includes a stator assembly and a rotor assembly, wherein the rotor assembly is the rotor assembly as described in claim 9.

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