Motor rotor and motor

Abstract

This utility model provides a motor rotor and a motor. The motor rotor includes: a rotating shaft with a first annular groove; and a rotor body comprising an iron core assembly, a permanent magnet assembly, and an injection-molded structure. The iron core assembly and the permanent magnet assembly are arranged around the rotating shaft. The injection-molded structure is formed on the surface of the rotating shaft and covers the first annular groove, connecting the rotating shaft, the iron core assembly, and the permanent magnet assembly into one unit. The motor rotor includes a first mounting position for mounting a first bearing. Along the axial direction of the rotating shaft, a first end of the first annular groove is located between the first mounting position and the rotor body. The first end of the first annular groove is the end of the first annular groove closest to the output side of the rotating shaft. The first mounting position is located between the output side of the rotating shaft and the rotor body. The motor rotor of this utility model embodiment solves the technical problem of high motor resonance noise in related technologies.

Description

Technical Field

[0001] This utility model relates to the field of motor design, and more specifically, to a motor rotor and a motor. Background Technology

[0002] During actual use, motors often experience resonance. When operating within a specific frequency range, resonance occurs, resulting in noticeable vibration and noise, which can lead to a poor user experience and even damage to components, thus negatively impacting the motor's performance.

[0003] In related technologies, the method of shielding the speed point where motor resonance occurs is usually used to avoid resonance. However, this may require shielding a wide speed range, which has an adverse effect on the use of the motor.

[0004] It is evident that the relevant technologies suffer from significant motor resonance noise. Currently, no effective solution has been proposed to address this issue.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background art described herein. Therefore, the background art may contain information that would not be considered part of the prior art by those skilled in the art. Utility Model Content

[0006] The main objective of this invention is to provide a motor rotor and a motor to solve the technical problem of excessive motor resonance noise in related technologies.

[0007] To achieve the above objectives, according to one aspect of the present invention, a motor rotor is provided, comprising: a rotating shaft having a first annular groove; and a rotor body comprising an iron core assembly, a permanent magnet assembly, and an injection-molded structure, wherein the iron core assembly and the permanent magnet assembly are arranged around the rotating shaft, the injection-molded structure is formed on the surface of the rotating shaft and covers the first annular groove, and the injection-molded structure connects the rotating shaft, the iron core assembly, and the permanent magnet assembly into one unit; wherein the motor rotor includes a first mounting position for mounting a first bearing, and along the axial direction of the rotating shaft, a first end of the first annular groove is located between the first mounting position and the rotor body, the first end of the first annular groove being the end of the first annular groove closer to the output side of the rotating shaft, and the first mounting position being located between the output side of the rotating shaft and the rotor body.

[0008] Furthermore, along the axial direction of the rotating shaft, the length of the first annular groove is less than or equal to 20 mm.

[0009] Furthermore, the depth of the first annular groove is greater than or equal to 0.5 mm.

[0010] Furthermore, a second annular groove is provided on the rotating shaft. Along the axial direction of the rotating shaft, the first annular groove is located between the second annular groove and the first mounting position. Along the axial direction of the rotating shaft, the first end of the second annular groove is located between the two end faces of the rotor body. The first end of the second annular groove is the end of the second annular groove closer to the output side of the rotating shaft.

[0011] Furthermore, the rotating shaft is provided with a third annular groove, and along the axial direction of the rotating shaft, the first annular groove is located between the third annular groove and the first mounting position; the motor rotor includes a second mounting position for mounting the second bearing, and along the axial direction of the rotating shaft, the first end of the third annular groove is located between the rotor body and the second mounting position, and the first end of the third annular groove is the end of the third annular groove near the output side of the rotating shaft.

[0012] Furthermore, along the axial direction of the rotating shaft, the total length of each annular groove is less than or equal to the distance between the first mounting position and the second mounting position.

[0013] Furthermore, the surface of the rotating shaft is provided with a connecting reinforcement structure. Along the axial direction of the rotating shaft, the connecting reinforcement structure is spaced apart from the first annular groove. The injection-molded structure covers the connecting reinforcement structure to increase the connection strength between the rotating shaft and the injection-molded structure.

[0014] Furthermore, the connection reinforcement structure includes a threaded structure, which is a recess or protrusion provided on the surface of the rotating shaft, and the threaded structure extends along the axial direction of the rotating shaft; and / or, the connection reinforcement structure includes a knurled structure, which is a recess or protrusion provided on the surface of the rotating shaft.

[0015] Furthermore, the core assembly includes multiple cores, which are arranged sequentially at intervals along the circumference of the shaft; the permanent magnet assembly includes multiple permanent magnets, with a permanent magnet provided between any two adjacent cores.

[0016] Furthermore, there is a gap between the core assembly and the shaft, and the injection molding structure fills the gap to fix the shaft and the core assembly together.

[0017] According to another aspect of the present invention, an electric motor is provided, comprising: a stator structure having a rotor mounting cavity; and a motor rotor, wherein the motor rotor is the aforementioned motor rotor and is mounted in the rotor mounting cavity.

[0018] The motor rotor using the technical solution of this utility model includes: a shaft with a first annular groove; and a rotor body comprising an iron core assembly, a permanent magnet assembly, and an injection-molded structure. The iron core assembly and the permanent magnet assembly are arranged around the shaft. The injection-molded structure is formed on the surface of the shaft and covers the first annular groove, connecting the shaft, the iron core assembly, and the permanent magnet assembly into a single unit. The motor rotor includes a first mounting position for mounting a first bearing. Along the axial direction of the shaft, the first end of the first annular groove is located between the first mounting position and the rotor body. The first end of the first annular groove is the end of the first annular groove closest to the output side of the shaft. The first mounting position is located between the output side of the shaft and the rotor body. In this structural design, the motor rotor shaft has a first annular groove. The iron core assembly and the permanent magnet assembly are fixed to the shaft by an injection-molded structure, which is injection-molded onto the surface of the shaft and covers the first annular groove. The end of the first annular groove closest to the output side of the shaft is located between the first mounting position of the first bearing and the rotor body. By designing the first annular groove, more injection molding material can be injected near the shaft during the injection molding process to form the injection-molded structure. Since the injection molding material is a polymer material with high damping, it can increase the overall damping performance of the rotor and suppress the resonance amplitude. The suppression effect on the resonance amplitude varies significantly depending on the location of the first annular groove. In this embodiment, the first end of the first annular groove is positioned between the first mounting position of the first bearing and the rotor body. Practical verification has shown that this groove placement method has a more significant effect on suppressing the rotor resonance amplitude compared to other groove placement methods, significantly reducing rotor vibration and noise, and solving the technical problem of excessive vibration and noise during motor operation in related technologies. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0020] Figure 1 This is an exploded structural diagram of an embodiment of the motor rotor of this utility model;

[0021] Figure 2 This is a schematic diagram of the structure of the rotating shaft in one embodiment of the motor rotor of this utility model;

[0022] Figure 3 for Figure 2 A magnified structural diagram of a local region in the diagram;

[0023] Figure 4 This is a schematic diagram of the shaft structure of another embodiment of the motor rotor of this utility model;

[0024] Figure 5 for Figure 4 A magnified structural diagram of a local region in the diagram;

[0025] Figure 6 This is a cross-sectional structural schematic diagram of an embodiment of the motor rotor of this utility model;

[0026] Figure 7 This is a schematic diagram comparing the noise levels of the motor in the present invention and related technologies at different speeds.

[0027] The above figures include the following reference numerals:

[0028] 1. Rotating shaft; 11. First annular groove; 13. Third annular groove; 2. Rotor body; 21. Iron core assembly; 211. Iron core; 22. Permanent magnet assembly; 221. Permanent magnet; 23. Injection molding structure; 3. First bearing; 4. Second bearing; 111. Threaded structure; 112. Knurled structure. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] Please refer to Figures 1 to 7 To address the technical problems in the background section, embodiments of this utility model provide a motor rotor, comprising: a rotating shaft 1, on which a first annular groove 11 is provided; and a rotor body 2, comprising an iron core assembly 21, a permanent magnet assembly 22, and an injection-molded structure 23. The iron core assembly 21 and the permanent magnet assembly 22 are arranged around the rotating shaft 1. The injection-molded structure 23 is formed on the surface of the rotating shaft 1 and covers the first annular groove 11. The injection-molded structure 23 connects the rotating shaft 1, the iron core assembly 21, and the permanent magnet assembly 22 into a single unit. The motor rotor includes a first mounting position for mounting a first bearing 3. Along the axial direction of the rotating shaft 1, the first end of the first annular groove 11 is located between the first mounting position and the rotor body 2. The first end of the first annular groove 11 is the end of the first annular groove 11 closer to the output side of the rotating shaft 1. The first mounting position is located between the output side of the rotating shaft 1 and the rotor body 2.

[0031] In this motor rotor design, a first annular groove 11 is provided on the rotor shaft 1. The iron core assembly 21 and the permanent magnet assembly 22 are fixed to the rotor shaft 1 by injection molding of an injection-molded structure 23, which is injection molded onto the surface of the rotor shaft 1 and covers the first annular groove 11. The end of the first annular groove 11 near the output side of the rotor shaft 1 is located between the first mounting position of the first bearing 3 and the rotor body 2. By designing the first annular groove 11, more injection molding material can be injected near the rotor shaft 1 during the injection molding process of the injection-molded structure 23. Since the injection molding material is a polymer material, its damping ratio is relatively large, which can increase the overall damping performance of the rotor and suppress the resonance amplitude. The suppression effect on the resonance amplitude varies significantly depending on the location of the first annular groove 11. In this embodiment, the first end of the first annular groove 11 is set between the first mounting position of the first bearing 3 and the rotor body 2. Practical verification has shown that this groove setting method has a more significant suppression effect on the rotor resonance amplitude compared with other groove setting methods. It can significantly reduce the vibration and noise of the rotor and solve the technical problem of large vibration and noise during motor operation in related technologies.

[0032] In actual implementation, the injection-molded structure 23 can be made of a variety of materials, such as PBT, PA46, PA66, PP, epoxy resin, etc.

[0033] like Figure 7 As shown, Figure 7 The dotted line represents the noise level of the motor using the structural design of this utility model embodiment during use. The other lines represent the noise level of the comparative schemes (including the scheme without the first annular groove 11 and the scheme with grooves in other positions) during use. It can be seen that the motor using the rotor of this utility model embodiment has significantly improved noise at various speeds compared with motors of other structures.

[0034] The first end of the first annular groove 11 is located between the first mounting position and the rotor body 2. Specifically, it can be flush with the side of the first mounting position close to the rotor body 2, or it can be flush with the side of the rotor body 2 close to the first mounting position, or it can be neither flush with the above two.

[0035] In a preferred embodiment, along the axial direction of the rotating shaft 1, the length of the first annular groove 11 is less than or equal to 20 mm, and the depth of the first annular groove 11 is greater than or equal to 0.5 mm.

[0036] In this embodiment, the length of the first annular groove 11 was further designed so that its axial length does not exceed 20mm. Practical experience has shown that within this groove length range, a significant resonance amplitude suppression effect can be achieved. Beyond this length, the noise suppression effect is not significantly improved, and it can have a significant impact on the strength and reliability of the shaft. By designing the length of the first annular groove 11 to be less than or equal to 20mm, motor vibration noise can be effectively suppressed while ensuring the structural strength of the shaft 1. In this embodiment, the depth of the first annular groove 11 is designed to be greater than or equal to 0.5mm. Its relatively deep depth allows for the filling of more injection molding material with a shorter first annular groove 11. Practical experience has shown that creating such a deep and short first annular groove 11 at the aforementioned location results in a more significant and better suppression effect on vibration noise than using a long and shallow groove.

[0037] Of course, based on the first annular groove 11 described above, other grooves can also be provided on the rotating shaft 1 without conflict:

[0038] For example, in some optional embodiments, the rotating shaft 1 is provided with a second annular groove (not shown in the figure), and along the axial direction of the rotating shaft 1, the first annular groove 11 is located between the second annular groove and the first mounting position; along the axial direction of the rotating shaft 1, the first end of the second annular groove is located between the two end faces of the rotor body 2, and the first end of the second annular groove is the end of the second annular groove near the output side of the rotating shaft 1.

[0039] For example, in some alternative embodiments, the rotating shaft 1 is provided with a third annular groove 13, and along the axial direction of the rotating shaft 1, the first annular groove 11 is located between the third annular groove 13 and the first mounting position; the motor rotor includes a second mounting position for mounting the second bearing 4, and along the axial direction of the rotating shaft 1, the first end of the third annular groove 13 is located between the rotor body 2 and the second mounting position, and the first end of the third annular groove 13 is the end of the third annular groove 13 near the output side of the rotating shaft 1.

[0040] Taking the output side of shaft 1 as the front end, the first annular groove 11 is biased towards the front end, the second annular groove is biased towards the middle, and the third annular groove 13 is biased towards the rear end. Based on the first annular groove 11, the second and third annular grooves 13 can also be selected and used according to actual conditions to adapt to different specifications of motor rotors, improving the adaptability to different rotors. They can be flexibly combined during use to adjust and suppress motor resonance and noise.

[0041] Specifically, along the axial direction of the rotating shaft 1, the total length of each annular groove is less than or equal to the distance between the first mounting position and the second mounting position.

[0042] In other words, when the first annular groove 11, the second annular groove and the third annular groove 13 are used in combination, their total axial length cannot exceed the distance between the first mounting position of the first bearing 3 and the second mounting position of the second bearing 4, so as to avoid affecting the installation of the first bearing 3 and the second bearing 4 and to ensure that the rotating shaft 1 has high structural strength.

[0043] In some preferred embodiments, the surface of the rotating shaft 1 is provided with a connecting reinforcement structure. Along the axial direction of the rotating shaft 1, the connecting reinforcement structure is spaced apart from the first annular groove 11. The injection-molded structure 23 covers the connecting reinforcement structure to increase the connection strength between the rotating shaft 1 and the injection-molded structure 23 through the connecting reinforcement structure.

[0044] By setting a connection reinforcement structure, the injection molding structure 23 is injection molded onto the connection reinforcement structure, which can improve the connection strength between the rotating shaft 1 and the injection molding structure 23, thereby improving the connection reliability between the rotating shaft 1, the iron core assembly 21, the permanent magnet assembly 22 and other structures, which is beneficial to the structural strength and vibration control of the motor.

[0045] Specifically, the connection reinforcement structure includes a threaded structure 111, which is a recess or protrusion on the surface of the rotating shaft 1, and the threaded structure 111 extends along the axial direction of the rotating shaft 1; and / or, the connection reinforcement structure includes a knurled structure 112, which is a recess or protrusion on the surface of the rotating shaft 1.

[0046] like Figures 1 to 5 As shown, the threaded structure 111 is a structure arranged in a helical manner; specifically, it can be a raised structure or a recessed structure. By designing the threaded structure 111, after the injection molding structure 23 is formed, the injection molding structure 23 and the rotating shaft 1 have a thread-like connection effect, increasing the axial connection strength between the two and preventing the rotor body 2 from sliding axially relative to the rotating shaft 1. By setting the knurled structure 112, the friction between the two can be further increased, reducing the risk of relative rotation between them. When used in conjunction with the threaded structure 111, it can prevent the threaded structure from failing due to relative rotation between the two, ensuring the connection strength between them. In a specific embodiment, the knurled structure 112 includes multiple strip-shaped protrusions, each extending axially along the rotating shaft 1, and the multiple strip-shaped protrusions are arranged sequentially at intervals along the circumference of the rotating shaft 1. Of course, in other embodiments, the specific shape of the knurled structure 112 can also be other choices, such as several protrusions, several recesses, etc.

[0047] Specifically, the core assembly 21 includes multiple cores 211, which are arranged sequentially at intervals along the circumference of the rotating shaft 1; the permanent magnet assembly 22 includes multiple permanent magnets 221, with a permanent magnet 221 provided between any two adjacent cores 211. A gap exists between the core assembly 21 and the rotating shaft 1, and the injection molding structure 23 fills the gap to fix the rotating shaft 1 and the core assembly 21 together.

[0048] It should be noted that in this embodiment, the core assembly 21 is not in direct contact with the rotating shaft 1. The inner diameter of the core assembly 21 is larger than the outer diameter of the rotating shaft 1, and the two are connected by the injection-molded structure 23. In related technologies, the core of an integral rotor is directly interference-fitted to the rotating shaft. Vibration is transmitted from the rotor to the rotating shaft and then to the housing. The entire vibration transmission path is made of steel, resulting in high vibration transmission rate, low damping, and almost no vibration attenuation effect. In this embodiment, the core assembly 21 is not in contact with the rotating shaft 1, but is connected by a polymer injection molding material. The polymer material can attenuate vibration in the vibration transmission path. In addition, when torsional vibration of the shaft occurs, the damping ratio of the polymer material is much higher than that of steel, which can also attenuate the resonance amplitude and reduce vibration and noise.

[0049] In addition, embodiments of this utility model also provide an electric motor, which includes: a stator structure having a rotor mounting cavity; and a motor rotor, which is the aforementioned motor rotor, and is mounted in the rotor mounting cavity.

[0050] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0051] The motor rotor of this embodiment includes: a rotating shaft 1, on which a first annular groove 11 is provided; a rotor body 2, which includes an iron core assembly 21, a permanent magnet assembly 22, and an injection molding structure 23. The iron core assembly 21 and the permanent magnet assembly 22 are arranged around the rotating shaft 1. The injection molding structure 23 is formed on the surface of the rotating shaft 1 and covers the first annular groove 11. The injection molding structure 23 connects the rotating shaft 1, the iron core assembly 21, and the permanent magnet assembly 22 into one unit. The motor rotor includes a first mounting position for mounting a first bearing 3. Along the axial direction of the rotating shaft 1, the first end of the first annular groove 11 is located between the first mounting position and the rotor body 2. The first end of the first annular groove 11 is the end of the first annular groove 11 near the output side of the rotating shaft 1. The first mounting position is located between the output side of the rotating shaft 1 and the rotor body 2. In this motor rotor design, a first annular groove 11 is provided on the rotor shaft 1. The iron core assembly 21 and the permanent magnet assembly 22 are fixed to the rotor shaft 1 by injection molding of an injection-molded structure 23, which is injection molded onto the surface of the rotor shaft 1 and covers the first annular groove 11. The end of the first annular groove 11 near the output side of the rotor shaft 1 is located between the first mounting position of the first bearing 3 and the rotor body 2. By designing the first annular groove 11, more injection molding material can be injected near the rotor shaft 1 during the injection molding process of the injection-molded structure 23. Since the injection molding material is a polymer material, its damping ratio is relatively large, which can increase the overall damping performance of the rotor and suppress the resonance amplitude. The suppression effect on the resonance amplitude varies significantly depending on the location of the first annular groove 11. In this embodiment, the first end of the first annular groove 11 is set between the first mounting position of the first bearing 3 and the rotor body 2. Practical verification has shown that this groove setting method has a more significant suppression effect on the rotor resonance amplitude compared with other groove setting methods. It can significantly reduce the vibration and noise of the rotor and solve the technical problem of large vibration and noise during motor operation in related technologies.

[0052] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0053] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0055] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A motor rotor, characterized in that, include: A rotating shaft (1) is provided with a first annular groove (11); The rotor body (2) includes an iron core assembly (21), a permanent magnet assembly (22), and an injection molding structure (23). The iron core assembly (21) and the permanent magnet assembly (22) are arranged around the rotating shaft (1). The injection molding structure (23) is formed on the surface of the rotating shaft (1) and covers the first annular groove (11). The injection molding structure (23) connects the rotating shaft (1), the iron core assembly (21), and the permanent magnet assembly (22) into one unit. The motor rotor includes a first mounting position for mounting a first bearing (3). Along the axial direction of the shaft (1), the first end of the first annular groove (11) is located between the first mounting position and the rotor body (2). The first end of the first annular groove (11) is the end of the first annular groove (11) near the output side of the shaft (1). The first mounting position is located between the output side of the shaft (1) and the rotor body (2).

2. The motor rotor according to claim 1, characterized in that, Along the axial direction of the rotating shaft (1), the length of the first annular groove (11) is less than or equal to 20 mm.

3. The motor rotor according to claim 1, characterized in that, The depth of the first annular groove (11) is greater than or equal to 0.5 mm.

4. The motor rotor according to claim 1, characterized in that, The rotating shaft (1) is provided with a second annular groove. Along the axial direction of the rotating shaft (1), the first annular groove (11) is located between the second annular groove and the first mounting position. Along the axial direction of the rotating shaft (1), the first end of the second annular groove is located between the two end faces of the rotor body (2). The first end of the second annular groove is the end of the second annular groove that is close to the output side of the rotating shaft (1).

5. The motor rotor according to claim 1 or 4, characterized in that, The rotating shaft (1) is provided with a third annular groove (13). Along the axial direction of the rotating shaft (1), the first annular groove (11) is located between the third annular groove (13) and the first mounting position. The motor rotor includes a second mounting position for mounting a second bearing (4). Along the axial direction of the rotating shaft (1), the first end of the third annular groove (13) is located between the rotor body (2) and the second mounting position. The first end of the third annular groove (13) is the end of the third annular groove (13) near the output side of the rotating shaft (1).

6. The motor rotor according to claim 5, characterized in that, Along the axial direction of the rotating shaft (1), the total length of each annular groove is less than or equal to the distance between the first mounting position and the second mounting position.

7. The motor rotor according to any one of claims 1 to 4, characterized in that, The surface of the rotating shaft (1) is provided with a connecting reinforcement structure. Along the axial direction of the rotating shaft (1), the connecting reinforcement structure is spaced apart from the first annular groove (11). The injection molding structure (23) covers the connecting reinforcement structure to increase the connection strength between the rotating shaft (1) and the injection molding structure (23) through the connecting reinforcement structure.

8. The motor rotor according to claim 7, characterized in that, The connection reinforcement structure includes a threaded structure (111), which is a recess or protrusion disposed on the surface of the rotating shaft (1), and the threaded structure (111) extends axially along the rotating shaft (1); and / or, The connection reinforcement structure includes a knurled structure (112), which is a recess or protrusion provided on the surface of the rotating shaft (1).

9. The motor rotor according to any one of claims 1 to 4, characterized in that, The core assembly (21) includes multiple cores (211), which are arranged sequentially at intervals along the circumference of the shaft (1); the permanent magnet assembly (22) includes multiple permanent magnets (221), and a permanent magnet (221) is provided between any two adjacent cores (211).

10. The motor rotor according to any one of claims 1 to 4, characterized in that, There is a gap between the core assembly (21) and the shaft (1), and the injection molding structure (23) fills the gap to fix the shaft (1) and the core assembly (21) together.

11. An electric motor, characterized in that, The motor includes: A stator structure having a rotor mounting cavity; The motor rotor is the motor rotor according to any one of claims 1 to 10, and the motor rotor is installed in the rotor mounting cavity.

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