Rotor assembly and motor

Abstract

The utility model discloses a rotor assembly and a motor. The rotor assembly comprises a rotor core and a permanent magnet component. The rotor core is provided with a plurality of first permanent magnet slots and a plurality of second permanent magnet slots, and the plurality of first permanent magnet slots and the plurality of second permanent magnet slots are alternately arranged along the circumferential direction of the rotor core. The permanent magnet component comprises a first permanent magnet and a second permanent magnet, the magnetic performance of the first permanent magnet is larger than that of the second permanent magnet, the first permanent magnet is arranged in the first permanent magnet groove, and the first permanent magnet and the second permanent magnet are arranged in the second permanent magnet groove. The problem that when a permanent magnet motor in the prior art adopts a strong magnetic permanent magnet and a weak magnetic permanent magnet for hybrid excitation, the weak magnetic permanent magnet is poor in demagnetization resistance can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of motors, and in particular to a rotor assembly and a motor. Background Art

[0002] Since the built-in permanent magnet motor uses permanent magnet excitation and has no rotor resistance loss during stable operation, it can effectively reduce the total loss. At present, most built-in permanent magnet motors use permanent magnets with strong magnetic properties. However, since permanent magnets account for most of the production cost of built-in permanent magnet motors, if there are too many strong permanent magnets, it is easy to increase the material cost of the motor. Therefore, on this basis, the built-in permanent magnet motor uses a mixed excitation of strong permanent magnets and weak permanent magnets, but weak permanent magnets have the defect of poor anti-demagnetization ability. At the same time, strong permanent magnets will be plated with a protective coating on the surface of the permanent magnet. In this way, when the permanent magnet is assembled on the rotor core, the protective coating will be scratched off, thereby affecting the service life of the magnetic steel. In addition, due to the problem of large magnetic leakage in the built-in permanent magnet motor, the utilization rate of the permanent magnet will be too low. Utility Model Content

[0003] The main purpose of the present application is to provide a rotor assembly and a motor to solve the problem that when the permanent magnet motor in the prior art adopts mixed excitation of strong magnetic permanent magnets and weak magnetic permanent magnets, the weak magnetic permanent magnets have poor anti-demagnetization ability.

[0004] According to one aspect of the present application, there is provided a rotor assembly, comprising:

[0005] A rotor core, wherein a plurality of first permanent magnet slots and a plurality of second permanent magnet slots are arranged on the rotor core, and the plurality of first permanent magnet slots and the plurality of second permanent magnet slots are alternately arranged along a circumferential direction of the rotor core;

[0006] A permanent magnet component, the permanent magnet component includes a first permanent magnet and a second permanent magnet, the magnetic property of the first permanent magnet is greater than the magnetic property of the second permanent magnet, the first permanent magnet is arranged in the first permanent magnet slot, and the first permanent magnet and the second permanent magnet are arranged in the second permanent magnet slot.

[0007] Further, the first permanent magnet slot includes a first section and a second section, the first section and the second section are connected, the first permanent magnet is inserted in the first section, the second section has a first limiting portion, the first limiting portion includes two, the two first limiting portions are arranged on opposite sides of the first section along the width direction of the first section, and the first permanent magnet abuts against the first limiting portion; and / or,

[0008] The second permanent magnet slot includes a third section and a fourth section, the third section and the fourth section are connected, the first permanent magnet and the second permanent magnet are inserted in the third section, the fourth section has a second limiting portion, the second limiting portion includes at least two, at least two second limiting portions are arranged on opposite sides of the third section along the length direction of the third section, and the first permanent magnet and the second permanent magnet are abutted against the second limiting portion.

[0009] Further, the first limiting portion is recessed from the edge of the second section toward the inner side of the second section; and / or,

[0010] The second limiting portion is recessed from the edge of the fourth section toward the inner side of the fourth section.

[0011] Furthermore, a magnetic attraction bridge is provided on the fourth segment, and the magnetic attraction bridge extends from the edge of the fourth segment toward the inner side of the fourth segment along the radial direction of the rotor core.

[0012] Furthermore, in the second permanent magnet slot, the second permanent magnet includes at least one, and along the radial direction of the rotor core, at least one of the second permanent magnets is connected in parallel with the first permanent magnet.

[0013] Furthermore, the second permanent magnets include two, and the first permanent magnet is arranged between the two second permanent magnets.

[0014] Furthermore, the second permanent magnets include four, and the four second permanent magnets are arranged around the outer circumference of the first permanent magnet.

[0015] Further, the first permanent magnet slot and the second permanent magnet slot are both long strip slots, wherein the first permanent magnet slot extends along the radial direction of the rotor core, and the second permanent magnet slot extends along the circumferential direction of the rotor core.

[0016] Further, the first permanent magnet includes a neodymium iron boron permanent magnet or a samarium cobalt permanent magnet; and / or,

[0017] The second permanent magnet includes an AlNiCo permanent magnet or a ferrite permanent magnet.

[0018] On the other hand, the present application also provides a motor, which includes the above-mentioned rotor assembly.

[0019] In the present application, when actually processing the rotor assembly, a plurality of first permanent magnet slots and a plurality of second permanent magnet slots can be processed on the rotor core, and the plurality of first permanent magnet slots and the plurality of second permanent magnet slots can be alternately arranged along the circumferential direction of the rotor core, that is, a second permanent magnet slot is arranged between two adjacent first permanent magnet slots, and then the first permanent magnet is inserted into the first permanent magnet slot. At the same time, the first permanent magnet and the second permanent magnet are connected in series and then inserted into the second permanent magnet slot, wherein the magnetic properties of the first permanent magnet are greater than the magnetic properties of the second permanent magnet. That is to say, compared with the motor structure that adopts mixed excitation of strong permanent magnets and weak permanent magnets in the prior art, the present application adopts a series-parallel mixed excitation structure of strong permanent magnets and weak permanent magnets, inserting the first permanent magnet in the first permanent magnet slot, and inserting the first permanent magnet and the second permanent magnet after series connection in the second permanent magnet slot. This can not only reduce the amount of the first permanent magnet, thereby reducing the material cost, but also improve the anti-demagnetization ability of the second permanent magnet in the second permanent magnet slot in the presence of the first permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 It is a schematic diagram of the structure of the rotor core disclosed in the embodiment of the present application;

[0022] Figure 2 The attached embodiment disclosed in this application Figure 1 A magnified schematic diagram of the middle A area;

[0023] Figure 3 (a) is a schematic structural diagram of the first second permanent magnet slot having only the first permanent magnet disclosed in an embodiment of the present application;

[0024] Figure 3 (b) is a schematic structural diagram of a second permanent magnet slot having only a first permanent magnet disclosed in an embodiment of the present application;

[0025] Figure 3 (c) is a schematic structural diagram of a third type of second permanent magnet slot having only a first permanent magnet disclosed in an embodiment of the present application;

[0026] Figure 4 (d) is a schematic structural diagram of the first second permanent magnet slot having a second permanent magnet and a first permanent magnet disclosed in an embodiment of the present application;

[0027] Figure 4 (e) is a schematic structural diagram of a second permanent magnet slot having a second permanent magnet and a first permanent magnet disclosed in an embodiment of the present application;

[0028] Figure 4 (f) is a schematic diagram of the structure of the third embodiment disclosed in the present application, which has a second permanent magnet and a first permanent magnet;

[0029] Figure 4 (g) is a schematic structural diagram of a fourth second permanent magnet slot having a second permanent magnet and a first permanent magnet disclosed in an embodiment of the present application;

[0030] Figure 5 (h) is a schematic structural diagram of the first second permanent magnet slot having two second permanent magnets and one first permanent magnet disclosed in an embodiment of the present application;

[0031] Figure 5 (i) is a schematic structural diagram of a second permanent magnet slot having two second permanent magnets and one first permanent magnet disclosed in an embodiment of the present application;

[0032] Figure 5 (j) is a schematic diagram of the structure of a second permanent magnet slot having four second permanent magnets and one first permanent magnet disclosed in an embodiment of the present application.

[0033] The above drawings include the following reference numerals:

[0034] 10. Rotor core; 20. First permanent magnet slot; 21. First section; 22. Second section; 221. First limiter; 30. Second permanent magnet slot; 31. Third section; 32. Fourth section; 321. Second limiter; 322. Magnet bridge; 40. Permanent magnet component; 41. First permanent magnet; 42. Second permanent magnet. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0038] As mentioned in the background technology, most of the existing built-in permanent magnet motors use permanent magnets with strong magnetic properties, but too many strong permanent magnets tend to increase the material cost of the motor, so the built-in permanent magnet motor uses a mixed excitation of strong permanent magnets and weak permanent magnets. However, the weak permanent magnet has poor anti-demagnetization ability, which can easily affect the use of the motor. Therefore, in order to reduce the amount of strong permanent magnets and improve the anti-demagnetization ability of weak permanent magnets, the inventor of the present application has designed a new rotor assembly, and the rotor assembly of the present application will be introduced in detail below.

[0039] It should be noted that the circumferential direction of the rotor core in this application is Figure 1 The letter Y indicates the direction, the width direction of the first segment and the length direction of the third segment are attached Figure 2 The direction indicated by the letter X.

[0040] See also Figures 1 to 5 As shown, the present application provides a rotor assembly, which includes a rotor core 10 and a permanent magnet component 40 .

[0041] Among them, the rotor core 10 is provided with a plurality of first permanent magnet slots 20 and a plurality of second permanent magnet slots 30, and the plurality of first permanent magnet slots 20 and the plurality of second permanent magnet slots 30 are alternately arranged along the circumferential direction of the rotor core 10; the permanent magnet component 40 includes a first permanent magnet 41 and a second permanent magnet 42, the magnetic properties of the first permanent magnet 41 are greater than the magnetic properties of the second permanent magnet 42, the first permanent magnet 41 is arranged in the first permanent magnet slot 20, and the first permanent magnet 41 and the second permanent magnet 42 are arranged in the second permanent magnet slot 30.

[0042] In this embodiment, the permanent magnet component 40 includes a first permanent magnet 41 and a second permanent magnet 42. When the rotor assembly is actually processed, a plurality of first permanent magnet slots 20 and a plurality of second permanent magnet slots 30 can be processed on the rotor core 10, and the plurality of first permanent magnet slots 20 and the plurality of second permanent magnet slots 30 are alternately arranged along the circumferential direction of the rotor core 10, that is, a second permanent magnet slot 30 is arranged between two adjacent first permanent magnet slots 20, and then the first permanent magnet 41 is inserted into the first permanent magnet slot 20, and at the same time, the first permanent magnet 41 and the second permanent magnet 42 are connected in series and then inserted into the second permanent magnet slot 30, wherein the magnetic properties of the first permanent magnet 41 are greater than the magnetic properties of the second permanent magnet 42.

[0043] That is to say, compared with the motor structure using strong permanent magnets and weak permanent magnets for mixed excitation in the prior art, the present embodiment uses a series-parallel mixed excitation structure of strong permanent magnets and weak permanent magnets, inserting the first permanent magnet 41 into the first permanent magnet slot 20, and inserting the first permanent magnet 41 and the second permanent magnet 42 after series connection into the second permanent magnet slot 30, which can not only reduce the amount of the first permanent magnet 41, thereby reducing the material cost, but also improve the anti-demagnetization ability of the second permanent magnet 42 in the second permanent magnet slot 30 in the presence of the first permanent magnet 41.

[0044] Further, see Figure 2 As shown, the first permanent magnet slot 20 in this embodiment includes a first section 21 and a second section 22, the first section 21 and the second section 22 are connected, the first permanent magnet 41 is inserted in the first section 21, and the second section 22 has a first limiting portion 221. The first limiting portion 221 includes two, and the two first limiting portions 221 are arranged on opposite sides of the first section 21 along the width direction of the first section 21, and the first permanent magnet 41 abuts against the first limiting portion 221. Specifically, the first limiting portion 221 can not only play a positioning role in the assembly of the first permanent magnet 41, but also play a fixing role on the first permanent magnet 41 to prevent the first permanent magnet 41 from moving in the first permanent magnet slot 20.

[0045] Further, see Figures 2 to 5 As shown, the second permanent magnet slot 30 in this embodiment includes a third section 31 and a fourth section 32, the third section 31 and the fourth section 32 are connected, the first permanent magnet 41 and the second permanent magnet 42 are inserted in the third section 31, and the fourth section 32 has a second limiting portion 321, the second limiting portion 321 includes at least two, at least two second limiting portions 321 are arranged on opposite sides of the third section 31 along the length direction of the third section 31, and the first permanent magnet 41 and the second permanent magnet 42 abut against the second limiting portion 321. Specifically, the second limiting portion 321 can not only play a positioning role in the assembly of the first permanent magnet 41 and the second permanent magnet 42 connected in series, but also fix the first permanent magnet 41 and the second permanent magnet 42 connected in series to prevent them from moving in the second permanent magnet slot 30.

[0046] It is understandable that the second limiting portion 321 may include two, three, four or more than four, as long as it can fix the first permanent magnet 41 and the second permanent magnet 42 after being connected in series. Figure 3 (a) To the attached Figure 5 (i) shows the situation when there are four second limiters 321. Specifically, along the length direction of the third section 31, two of the four second limiters 321 and the other two of the four second limiters 321 are arranged on opposite sides of the third section 31, and the first permanent magnet 41 and the second permanent magnet 42 connected in series abut against the four second limiters 321. Figure 5 (j) shows the case where there are two second limiting portions 321 .

[0047] Specifically, the first limiting portion 221 of the present embodiment is recessed from the edge of the second section 22 toward the inner side of the second section 22 to fix the first permanent magnet 41; and / or, the second limiting portion 321 is recessed from the edge of the fourth section 32 toward the inner side of the fourth section 32 to fix the first permanent magnet 41 and the second permanent magnet 42 connected in series. It can be understood that the first limiting portion 221 and the second limiting portion 321 can be a bilateral structure, or a triangular structure, a quadrilateral structure, a polygonal structure, a special-shaped structure or an arc structure. As long as it can ensure that the first permanent magnet 41 abuts against the first limiting portion 221, and the first permanent magnet 41 and the second permanent magnet 42 connected in series abut against the second limiting portion 321, the present application does not make specific limitations on the structures of the first limiting portion 221 and the second limiting portion 321. Appendix of the present embodiment Figure 2 The first limiting portion 221 is a triangular structure. Figure 3 (a) To the attached Figure 5 (j) shows the situations when the second limiting portion 321 is a double-sided structure and a triangular structure.

[0048] Further, in order to improve the utilization rate of permanent magnets, see Figure 2 As shown, in this embodiment, a magnetizing bridge 322 is provided on the fourth section 32, and the magnetizing bridge 322 extends from the edge of the fourth section 32 toward the inner side of the fourth section 32 along the radial direction of the rotor core 10. Since the existing built-in motor has magnetic leakage, it is easy to reduce the utilization rate of the permanent magnet. Therefore, in this embodiment, a magnetizing bridge 322 is provided on the second limit portion 321. When the motor starts to work, the existence of the magnetizing bridge 322 can redirect the leakage magnetic flux into the main magnetic flux, thereby improving the utilization rate of the permanent magnet, and further improving the operating efficiency of the motor.

[0049] Specifically, the first permanent magnet 41 in this embodiment includes a neodymium iron boron permanent magnet or a samarium cobalt permanent magnet; and / or, the second permanent magnet 42 includes an aluminum nickel cobalt permanent magnet or a ferrite permanent magnet. Specifically, this embodiment defines the first permanent magnet 41 as a strong magnetic permanent magnet, and defines the second permanent magnet 42 as a weak magnetic permanent magnet. Among them, the neodymium iron boron permanent magnet has high magnetic properties and strong machinability; the samarium cobalt permanent magnet has a high magnetic energy product and an extremely low temperature coefficient. Compared with neodymium iron boron, the samarium cobalt permanent magnet is more suitable for working in a high temperature environment; the aluminum nickel cobalt permanent magnet has a high remanence, but a low coercive force; the ferrite permanent magnet is suitable for working in a dynamic magnetic circuit environment with large temperature changes. It is not easy to corrode and generally does not require a coating.

[0050] Further, in the second permanent magnet slot 30, the second permanent magnet 42 in this embodiment includes at least one, and along the radial direction of the rotor core 10, at least one second permanent magnet 42 is connected in parallel with the first permanent magnet 41. That is to say, the second permanent magnet 42 may include one, two, three, or four. In order to prevent the permanent magnet from being oxidized during operation, a protective coating is generally plated on the surface of the permanent magnet. When the permanent magnet is assembled on the rotor core 10, the protective coating will be scratched off, thereby affecting the service life of the magnetic steel. Therefore, in this embodiment, since the first permanent magnet 41 will oxidize during use, the present application is coated with a protective coating on the surface of the first permanent magnet 41, and since the magnetic material used by the second permanent magnet 42 is not easily oxidized, the surface of the second permanent magnet 42 is not coated with a protective coating. In this way, when the first permanent magnet 41 and the second permanent magnet 42 connected in series are inserted into the second permanent magnet slot 30, the presence of the second permanent magnet 42 reduces the contact area between the first permanent magnet 41 and the second permanent magnet slot 30, thereby reducing the probability of the protective coating coated on the surface of the first permanent magnet 41 being scratched, thereby avoiding oxidation of the first permanent magnet 41, and thus extending the service life of the motor to a certain extent.

[0051] Specifically, the protective coating in this embodiment includes a nickel-plated coating, a zinc-plated coating, a gold-plated coating, or the like.

[0052] Specifically, see Figure 4 (d) to Figure 4 As shown in (g), in one embodiment shown in the present application, the second permanent magnet 42 includes one.

[0053] Specifically, see Figure 5 (h) to Figure 5(i) As shown, in another embodiment shown in the present application, the second permanent magnet 42 includes two, and the first permanent magnet 41 is arranged between the two second permanent magnets 42. In this way, on the basis of only one second permanent magnet 42, the presence of the two second permanent magnets 42 further reduces the contact area between the first permanent magnet 41 and the second permanent magnet slot 30, thereby preventing the first permanent magnet 41 from being oxidized, extending the service life of the motor to a certain extent, and at the same time, reducing the usage of the first permanent magnet 41, thereby reducing the production cost of the motor.

[0054] Further, see Figure 5 (j) As shown, in another embodiment shown in the present application, the second permanent magnet 42 includes four, and the four second permanent magnets 42 are arranged around the outer periphery of the first permanent magnet 41. In this way, the presence of the second permanent magnet 42 further reduces the contact area between the first permanent magnet 41 and the second permanent magnet slot 30, thereby preventing the first permanent magnet 41 from being oxidized, extending the service life of the motor to a certain extent, and at the same time, further reducing the usage of the first permanent magnet 41, thereby reducing the production cost of the motor. At this time, the second permanent magnet 42 abuts against the second limit portion 321.

[0055] Further, see Figure 2 As shown, the first permanent magnet slot 20 and the second permanent magnet slot 30 in this embodiment are both long strip slots, wherein the first permanent magnet slot 20 extends in the radial direction of the rotor core 10, and the second permanent magnet slot 30 extends in the circumferential direction of the rotor core 10. In this embodiment, the first permanent magnet 41 in the first permanent magnet slot 20 is magnetized tangentially, and the first permanent magnet 41 and the second permanent magnet 42 in the second permanent magnet slot 30 are magnetized radially. Specifically, strong permanent magnets are used for excitation at tangential excitation positions with larger magnetic field impact, and strong permanent magnets and weak permanent magnets are used for series excitation at radial excitation positions with smaller magnetic field impact.

[0056] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects: relative to the motor structure of the prior art with mixed excitation of strong permanent magnets and weak permanent magnets, the present application adopts strong permanent magnet excitation at the tangential excitation position with larger magnetic field impact, and adopts strong permanent magnet and weak permanent magnet series excitation at the radial excitation position with smaller magnetic field impact, which not only reduces the usage of strong permanent magnets, thereby reducing the material cost of the motor, but also improves the anti-demagnetization ability of the rotor assembly of the motor. At the same time, the present application sets a magnetic induction bridge on the second permanent magnet slot, which can guide the leakage magnetic flux into the main magnetic flux, thereby improving the utilization rate of the permanent magnet. In addition, the presence of weak permanent magnets in the present application reduces the contact area between the strong permanent magnet and the rotor core, effectively avoiding the oxidation of the strong permanent magnet, and extending the service life of the motor.

[0057] On the other hand, the embodiment of the present application further provides a motor, which includes the above-mentioned rotor assembly, and thus the motor includes all the technical effects of the above-mentioned rotor assembly. Since the technical effects of the rotor assembly have been described in detail above, they will not be repeated here.

[0058] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0059] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0060] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A rotor assembly, characterized in that: include: A rotor core (10), wherein a plurality of first permanent magnet slots (20) and a plurality of second permanent magnet slots (30) are provided on the rotor core (10), and the plurality of first permanent magnet slots (20) and the plurality of second permanent magnet slots (30) are alternately arranged along a circumferential direction of the rotor core (10); A permanent magnet component (40), the permanent magnet component (40) comprising a first permanent magnet (41) and a second permanent magnet (42), the magnetic properties of the first permanent magnet (41) being greater than the magnetic properties of the second permanent magnet (42), the first permanent magnet (41) being arranged in the first permanent magnet slot (20), and the first permanent magnet (41) and the second permanent magnet (42) being arranged in the second permanent magnet slot (30).

2. The rotor assembly according to claim 1, characterized in that: The first permanent magnet slot (20) comprises a first section (21) and a second section (22), the first section (21) and the second section (22) are connected, the first permanent magnet (41) is inserted into the first section (21), the second section (22) has a first limiting portion (221), the first limiting portion (221) comprises two first limiting portions (221), the two first limiting portions (221) are arranged on opposite sides of the first section (21) along the width direction of the first section (21), and the first permanent magnet (41) abuts against the first limiting portion (221); and / or, The second permanent magnet slot (30) comprises a third section (31) and a fourth section (32), the third section (31) and the fourth section (32) are connected, the first permanent magnet (41) and the second permanent magnet (42) are inserted into the third section (31), the fourth section (32) has a second limiting portion (321), the second limiting portion (321) comprises at least two, at least two second limiting portions (321) are arranged on opposite sides of the third section (31) along the length direction of the third section (31), and the first permanent magnet (41) and the second permanent magnet (42) are abutted against the second limiting portion (321).

3. The rotor assembly according to claim 2, characterized in that: The first limiting portion (221) is recessed from the edge of the second section (22) toward the inner side of the second section (22); and / or, The second limiting portion (321) is recessed from the edge of the fourth section (32) toward the inner side of the fourth section (32).

4. The rotor assembly according to claim 2, characterized in that: The fourth section (32) is provided with a magnetic attraction bridge (322), and the magnetic attraction bridge (322) extends from the edge of the fourth section (32) toward the inner side of the fourth section (32) along the radial direction of the rotor core (10).

5. The rotor assembly according to claim 1, characterized in that: In the second permanent magnet slot (30), the second permanent magnet (42) includes at least one, and along the radial direction of the rotor core (10), at least one of the second permanent magnets (42) is connected in parallel with the first permanent magnet (41).

6. The rotor assembly according to claim 5, characterized in that The second permanent magnets (42) include two, and the first permanent magnet (41) is arranged between the two second permanent magnets (42).

7. The rotor assembly according to claim 5, characterized in that: The second permanent magnets (42) include four second permanent magnets (42), and the four second permanent magnets (42) are arranged around the outer periphery of the first permanent magnet (41).

8. The rotor assembly according to any one of claims 1 to 7, characterized in that: The first permanent magnet slot (20) and the second permanent magnet slot (30) are both long strip slots, wherein the first permanent magnet slot (20) extends in the radial direction of the rotor core (10), and the second permanent magnet slot (30) extends in the circumferential direction of the rotor core (10).

9. The rotor assembly according to any one of claims 1 to 7, characterized in that: The first permanent magnet (41) comprises a neodymium iron boron permanent magnet or a samarium cobalt permanent magnet; and / or, The second permanent magnet (42) comprises an AlNiCo permanent magnet or a ferrite permanent magnet.

10. A motor, characterized in that: The electric machine comprises the rotor assembly according to any one of claims 1 to 9.

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