Rotor structure, method of forming same, and electric machine

Abstract

This invention provides a rotor structure, its molding method, and an electric motor. The rotor structure includes: an outer rotor core (6), with multiple outer rotor cores (6) arranged circumferentially at intervals, and mounting grooves (5) formed between adjacent outer rotor cores (6); tangential ferrite (2), disposed within the mounting grooves (5) and used to form a tangential magnetic field; an axial plastic magnetic disk (4), disposed at both axial ends of the outer rotor core and used to form an axial magnetic field; and a plastic-coated shell (1), which wraps around the outer rotor core (6), tangential ferrite (2), and axial plastic magnetic disk (4), and injection molds the outer rotor core (6), tangential ferrite (2), and axial plastic magnetic disk (4) into a single unit. According to the rotor structure of this invention, the assembly difficulty of the rotor structure can be reduced, the assembly effect improved, and the working performance and reliability of the electric motor guaranteed.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more specifically, to a rotor structure, its molding method, and a motor. Background Technology

[0002] With increasing global emphasis on energy conservation, emission reduction, and green energy, motor energy efficiency standards are constantly being raised, placing more stringent demands on the high efficiency and high torque density of permanent magnet motors. Due to their advantages such as high efficiency, high power density, and low noise, permanent magnet motors are widely used in home appliances, automobiles, and industrial drives. However, improving the performance of permanent magnet motors also faces technological challenges and limitations.

[0003] Traditional permanent magnet motors typically employ tangential or radial magnetization to create the necessary magnetic field. However, these methods have significant limitations in practical applications. With tangential magnetization, the magnetic field direction is perpendicular to the motor axis; with radial magnetization, it's parallel. Regardless of the method, the magnetic field is not completely enclosed in space, causing some magnetic field lines to "leak" at both ends of the motor axis, a phenomenon known as "magnetic leakage." This leakage not only reduces the effective magnetic flux of the permanent magnet and decreases the air gap magnetic flux density of the motor, but also degrades the material properties of the permanent magnet, directly impacting the motor's efficiency and torque density.

[0004] To address the problem of magnetic leakage and improve the utilization efficiency of permanent magnets, existing technologies have proposed a series of improvement schemes. One common approach is to add axial magnets at both ends of the motor. These axial magnets are magnetized axially. Theoretically, the addition of axial magnets can form a more closed magnetic circuit, thereby reducing magnetic leakage at both ends of the permanent magnet motor and improving the utilization efficiency of the permanent magnets.

[0005] The above-mentioned scheme is not only complex and difficult to assemble due to the large number of parts, but also results in poor assembly quality. Summary of the Invention

[0006] The main objective of this invention is to provide a rotor structure, its forming method, and an electric motor, which can reduce the assembly difficulty of the rotor structure, improve the assembly effect, and ensure the working performance and reliability of the motor.

[0007] To achieve the above objectives, according to one aspect of the present invention, a rotor structure is provided, comprising:

[0008] Outer rotor cores, multiple outer rotor cores are arranged at intervals along the circumference, and mounting slots are formed between adjacent outer rotor cores;

[0009] Tangential ferrite is placed in the mounting slot and used to generate a tangential magnetic field;

[0010] An axial plastic magnetic disk is disposed at both ends of the outer rotor core and is used to generate an axial magnetic field.

[0011] The plastic-coated shell encapsulates the outer rotor core, tangential ferrite, and axial plastic magnetic disk, and injection molds the outer rotor core, tangential ferrite, and axial plastic magnetic disk into a single unit.

[0012] Furthermore, there is an installation gap between the outer rotor core and the tangential ferrite, and the plastic-coated housing includes an end connection portion wrapped around the axial plastic magnetic disk, an axial connection portion connected to the radially outer side of the end connection portion, an inner ring connection portion connected to the radially inner side of the end connection portion, and an injection-molded connection layer filled in the installation gap.

[0013] Furthermore, the outer radial side of the outer rotor core extends circumferentially to both sides to form a first lateral protrusion, which forms a radial stop against the tangential ferrite.

[0014] Furthermore, the axial connecting portion is correspondingly disposed on the outer peripheral side of the tangential ferrite, and the radially outer side of the axial connecting portion extends to both sides in the circumferential direction to form a second lateral protrusion. The first lateral protrusion is located on the radially inner side of the second lateral protrusion, and a radial stop is formed by the second lateral protrusion.

[0015] Furthermore, the axial height of the tangential ferrite is higher than the axial height of the outer rotor core, and a positioning groove is provided on the side of the axial plastic magnetic disk facing the tangential ferrite, with the part of the tangential ferrite extending out of the outer rotor core being inserted into the positioning groove.

[0016] Furthermore, an injection molding groove is provided on the outer periphery of the axial plastic magnetic disk, and the position of the injection molding groove corresponds to the outer periphery of the tangential ferrite.

[0017] Furthermore, the rotor structure also includes an inner rotor core and damping rubber. The plastic-coated shell has a mounting through hole. Multiple first protrusions are spaced apart circumferentially on the inner wall of the mounting through hole. Second protrusions are spaced apart circumferentially on the outer peripheral wall of the inner rotor core. A first groove is formed between adjacent first protrusions, and a second groove is formed between adjacent second protrusions. The first protrusions are disposed in the second grooves and form a filling gap with the inner wall of the second grooves. The second protrusions are disposed in the first grooves and form a filling gap with the inner wall of the first grooves. The damping rubber fills the filling gaps.

[0018] Furthermore, the outer rotor core is provided with a first positioning hole through it along the axial direction. The first positioning hole is a non-circular hole and is filled with damping adhesive. And / or, the inner rotor core is provided with an injection hole along the axial direction and is filled with damping adhesive.

[0019] Furthermore, both the first positioning hole and the injection hole are filled with damping adhesive, and damping adhesive is provided on the outer end face of the axial plastic magnetic disk. A third positioning hole is provided circumferentially through the first positioning hole on the axial plastic magnetic disk. The third positioning hole is a non-circular hole. The damping adhesive flows into the first positioning hole through the third positioning hole. The first positioning hole, the injection hole, the outer end face of the axial plastic magnetic disk, and the damping adhesive in the third positioning hole are an integral structure, and the damping adhesive forms a cage-like structure.

[0020] Furthermore, the inner rotor core has a central shaft hole, and a second positioning hole is provided on the inner wall of the central shaft hole to position the circumferential relative position of the inner rotor core and the plastic-coated shell.

[0021] Furthermore, the tangential ferrite and the axial plastic magnetic disk are formed on the same outer rotor core with the same polarity, while the polarities of two adjacent outer rotor cores along the circumferential direction are opposite.

[0022] Furthermore, the maximum distance between the outer periphery of the outer rotor core and the central axis of the plastic-coated shell is greater than or equal to the maximum distance between the outer periphery of the tangential ferrite and the central axis of the plastic-coated shell.

[0023] Furthermore, the thickness of the damping adhesive between the inner rotor core and the plastic-coated shell is L5≥0.5mm, the thickness of the damping adhesive at the outer end of the axial plastic magnetic disk is L6≥1mm, and the overlap dimension of the inner rotor core and the plastic-coated shell in the tangential direction is L7≥1mm.

[0024] Furthermore, the maximum diameter of the rotor's outer circle is D1, and the diameter of the mounting through hole is D3, with 0.25*D1≤D3≤0.5*D1.

[0025] Furthermore, the axial thickness of the axial plastic magnetic disk is L8, and the total axial thickness of the rotor structure is L9, with 0.1*L9≤L8≤0.4*L9.

[0026] According to another aspect of the present invention, a method for forming the above-described rotor structure is provided, comprising:

[0027] Fabrication of axial plastic magnetic disks;

[0028] Multiple rotor laminations are stacked together to form the outer rotor core;

[0029] Place the axial plastic magnetic disk into the mold and fix it in place;

[0030] Multiple external rotor cores are mounted and fixed on an axial plastic magnetic disk.

[0031] The tangential ferrite is installed and positioned in the mounting slot between adjacent outer rotor cores;

[0032] Plastic is injected into the mold to encapsulate the axial plastic magnetic disk, the outer rotor core, and the tangential ferrite into an outer rotor structure, and the outer rotor structure is then magnetized and oriented.

[0033] Furthermore, the molding method also includes:

[0034] The inner rotor core is placed into the mold, and the relative positions of the inner rotor core and the outer rotor structure are defined.

[0035] Shock-absorbing adhesive is injected into the mold to encapsulate the outer rotor structure and the inner rotor core into one unit.

[0036] Furthermore, the steps of placing and positioning the outer rotor core into the mold include:

[0037] The outer rotor core is placed into the axial plastic magnetic disk for positioning through the first positioning hole.

[0038] According to another aspect of the present invention, an electric motor is provided, comprising a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above, and the stator structure is sleeved on the outer periphery of the rotor structure.

[0039] According to the technical solution of this invention, the rotor structure includes: an outer rotor core, with multiple outer rotor cores arranged circumferentially at intervals, forming mounting slots between adjacent outer rotor cores; tangential ferrite, disposed within the mounting slots and used to generate a tangential magnetic field; an axial plastic magnetic disk, disposed at both axial ends of the outer rotor cores and used to generate an axial magnetic field; and a plastic-coated shell, encasing the outer rotor cores, tangential ferrite, and axial plastic magnetic disk, and injection molding the outer rotor cores, tangential ferrite, and axial plastic magnetic disk into a single unit. The plastic-coated shell is integrally injection molded from plastic, integrating the tangential ferrite, outer rotor core, and axial plastic magnetic disk together. Compared to traditional assembly methods, integral injection molding can reduce errors during assembly, improve the accuracy and reliability of the overall structure, simplify the production process, and reduce production costs. Since the tangential ferrite and axial plastic magnetic disk are magnetized after being injection molded together with the outer rotor core through a plastic-coated shell, the types and number of permanent magnet rotor parts and the corresponding assembly processes can be reduced. There is no problem of mutual repulsion between different parts during assembly. The production process is relatively simple, the assembly difficulty is greatly reduced, and the reliability of motor assembly can be effectively improved. Attached Figure Description

[0040] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1 A perspective structural diagram of the rotor structure according to an embodiment of the present invention is shown;

[0042] Figure 2 An exploded structural diagram of the rotor structure according to an embodiment of the present invention is shown;

[0043] Figure 3 A schematic diagram of the outer rotor core of an embodiment of the present invention is shown;

[0044] Figure 4 A schematic diagram of the arrangement structure of the outer rotor core of an embodiment of the present invention is shown;

[0045] Figure 5 A schematic diagram of the structure of an axial plastic magnetic disk according to an embodiment of the present invention is shown;

[0046] Figure 6 It shows Figure 5 A schematic diagram of the AA-direction cross-section structure;

[0047] Figure 7 A rear view structural schematic diagram of an axial plastic magnetic disk according to an embodiment of the present invention is shown;

[0048] Figure 8 A schematic diagram of the external rotor structure according to an embodiment of the present invention is shown;

[0049] Figure 9 It shows Figure 8 Schematic diagram of the BB-direction cross-section structure;

[0050] Figure 10 It shows Figure 9 Schematic diagram of the CC-direction cross-section structure;

[0051] Figure 11 A schematic diagram of the structure of the inner rotor core according to an embodiment of the present invention is shown;

[0052] Figure 12 A three-dimensional structural schematic diagram of the inner rotor core according to an embodiment of the present invention is shown;

[0053] Figure 13 A cross-sectional structural diagram of the shock-absorbing adhesive according to an embodiment of the present invention is shown;

[0054] Figure 14 A schematic diagram of the rotor structure according to an embodiment of the present invention is shown;

[0055] Figure 15 It shows Figure 14 A schematic diagram of the DD-direction cross-sectional structure; and

[0056] Figure 16 It shows Figure 15 A schematic diagram of the EE cross-section structure.

[0057] The above figures include the following reference numerals:

[0058] 1. Plastic-coated shell; 2. Tangential ferrite; 3. Inner ring connecting part; 4. Axial plastic magnetic disk; 5. Mounting groove; 6. Outer rotor core; 7. Inner rotor core; 8. Shock-absorbing rubber; 9. Mounting through hole; 10. First protrusion; 11. Second protrusion; 12. First groove; 13. Second groove; 14. Filling gap; 15. Injection groove; 16. First positioning hole; 17. Injection hole; 18. Third positioning hole; 19. Central shaft hole; 20. Second positioning hole; 21. Second lateral protrusion; 22. End connecting part; 23. Axial connecting part; 24. Injection-molded connecting layer; 25. First lateral protrusion; 26. Positioning groove; 27. Flow hole. Detailed Implementation

[0059] 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.

[0060] See also Figures 1 to 16 As shown, according to an embodiment of the present invention, the rotor structure includes: an outer rotor core 6, a plurality of outer rotor cores 6 arranged at circumferential intervals, and an mounting groove 5 formed between adjacent outer rotor cores 6; a tangential ferrite 2 disposed in the mounting groove 5 and used to form a tangential magnetic field; an axial plastic magnetic disk 4 disposed at both ends of the outer rotor core and used to form an axial magnetic field; and a plastic-coated shell 1, which wraps around the outer rotor core 6, the tangential ferrite 2 and the axial plastic magnetic disk 4, and injection molds the outer rotor core 6, the tangential ferrite 2 and the axial plastic magnetic disk 4 into one piece.

[0061] In this embodiment, the plastic-coated housing 1 is integrally injection molded from plastic, integrating the tangential ferrite 2, the outer rotor core 6, and the axial plastic magnetic disk 4 together. Compared with traditional assembly methods, integral injection molding can reduce errors in the assembly process, improve the accuracy and reliability of the overall structure, and simplify the production process, thereby reducing production costs. Since the tangential ferrite 2 and the axial plastic magnetic disk 4 are magnetized after being integrally injection molded with the outer rotor core 6 through the plastic-coated housing 1, the types and number of permanent magnet rotor parts and the corresponding assembly steps can be reduced. There is no problem of mutual repulsion between different parts during assembly, the production process is relatively simple, the assembly difficulty is greatly reduced, and the reliability of motor assembly can be effectively improved.

[0062] By setting tangential ferrite 2 and axial plastic magnetic disk 4, tangential magnetic field and axial magnetic field can be formed respectively, realizing the three-dimensional spatial distribution of the excitation source magnetization circuit, that is, the parallel magnetic circuit of tangential and axial. It can realize that the excitation source magnetization circuit is two parallel circuits in three-dimensional space of tangential and axial, thereby improving the performance of the motor, reducing the size of the motor, enhancing the magnetic cohesion effect of the motor, and improving the utilization efficiency of magnetic force.

[0063] The mounting slots 5 between the outer rotor cores 6 provide mounting positions for the tangential ferrites 2. The outer rotor cores 6 are arranged at intervals along the circumference of the plastic-coated shell 1, and they precisely fit with the tangential ferrites 2, ensuring the continuity and stability of the magnetic circuit. By setting axial plastic magnetic disks 4 at both ends of the tangential ferrites 2, leakage flux can be effectively reduced, the utilization efficiency of permanent magnets can be improved, and the mechanical strength of the rotor structure can be increased. This also reduces stress concentration during high-speed operation or when subjected to external impact, avoids structural damage, and improves the reliability and lifespan of the motor.

[0064] The rotor excitation source consists of two main parts: the tangential part, whose magnetization direction is perpendicular to the rotor radius and is a ferrite structure; and the axial part, whose magnetization direction is parallel to the rotor shaft. The tangential part is evenly distributed circumferentially, while the axial part is distributed at the upper and lower ends of the tangential part. The axial excitation source is injection molded from permanent magnet material, typically using plastic magnetic ferrite particles.

[0065] The outer rotor core 6, tangential ferrite 2 and axial plastic magnetic disk 4 are integrally formed by using a plastic-coated shell 1, which simplifies the positioning and fixing steps in the assembly process, enables highly automated production, greatly improves production efficiency and reduces production costs.

[0066] The outer rotor core 6, tangential ferrite 2, and axial plastic magnetic disk 4 are fixed together by injection molding through a plastic-coated housing 1, which makes the connection between the various components firm, avoids the failure of the fit during high temperature and high speed operation, and ensures the stability of motor operation.

[0067] In one embodiment, there is an installation gap between the outer rotor core and the tangential ferrite, and the plastic-coated housing 1 includes an end connection portion 22 wrapped around the axial plastic magnetic disk 4, an axial connection portion 23 connected to the radially outer side of the end connection portion 22, an inner ring connection portion 3 connected to the radially inner side of the end connection portion 22, and an injection-molded connection layer 24 filled in the installation gap.

[0068] The installation gap between the outer rotor core 6 and the tangential ferrite 2 serves two purposes: firstly, it reduces the difficulty of installing the tangential ferrite 2 into the mounting slot 5 between adjacent outer rotor cores 6, improving installation efficiency; secondly, it prevents friction between the tangential ferrite 2 and the outer rotor core 6 during installation, which could damage the magnetic circuit structure of the tangential ferrite 2, reduce its magnetic properties, and decrease its magnetic field strength. The installation gap allows for optimal magnetic coupling between the tangential ferrite 2 and the outer rotor core 6. Simultaneously, the filling of the injection-molded connecting layer 24 ensures a stable bond between the tangential ferrite 2 and the outer rotor core 6, reducing component displacement caused by magnetic fluctuations during high-speed operation and ensuring the stability and efficiency of the magnetic circuit.

[0069] The design of the end connection portion 22 and the axial connection portion 23 not only fixes the axial plastic magnetic disk 4 to both ends of the outer rotor core 6, but also provides additional mechanical support for the entire rotor structure through the rigidity of the injection molding material, enhancing the axial and radial structural strength and improving the stability and reliability of the rotor under high-speed and high-load conditions. The injection-molded connection layer 24 fills the installation gap, forming a thermal insulation layer, which helps prevent the heat generated during motor operation from being directly conducted from the tangential ferrite 2 to the outer rotor core 6, reducing the impact of thermal stress on the magnetic material, thereby improving the thermal stability of the motor.

[0070] The end connection 22, axial connection 23, and inner ring connection 3 of the plastic-coated housing 1 can be injection molded in one step, integrating all rotor components into a single unit. This greatly simplifies the assembly process, reduces production complexity and cost, and avoids assembly errors that may occur in traditional assembly methods. By designing a plastic-coated housing structure with specific functions, the distribution of injection molding material can be precisely controlled, avoiding material waste, improving material utilization, and thus reducing the manufacturing cost of the motor.

[0071] In one embodiment, the outer rotor core 6 extends radially outward to both sides in the circumferential direction to form a first lateral protrusion 25, which forms a radial stop on the tangential ferrite 2.

[0072] By forming a first lateral protrusion 25 extending circumferentially to both sides on the radially outer side of the outer rotor core 6, the accurate positioning of the tangential ferrite 2 during assembly can be ensured, avoiding uneven magnetic field distribution caused by inaccurate positioning, thereby optimizing the electromagnetic performance of the motor. The radial stop effectively prevents radial displacement of the tangential ferrite 2 when the motor is running at high speed or subjected to vibration, enhancing the stability between rotor components, avoiding changes in the magnetic circuit and degradation of motor performance caused by component displacement, and improving the reliability and service life of the motor.

[0073] In one embodiment, the axial connecting portion 23 is correspondingly disposed on the outer peripheral side of the tangential ferrite 2, and the radially outer side of the axial connecting portion 23 extends to both sides in the circumferential direction to form a second lateral protrusion 21. The first lateral protrusion 25 is located on the radially inner side of the second lateral protrusion 21 and forms a radial stop by the second lateral protrusion 21.

[0074] The second lateral protrusion 21 is formed radially outward, forming an inner and outer stop structure with the first lateral protrusion 25. This structure provides radial positioning for the outer rotor core 6, ensuring precise positioning and fixation of the outer rotor core 6 and the tangential ferrite 2 in the radial direction. This effectively prevents radial movement of the outer rotor core 6 and the tangential ferrite 2 under high-speed operation or external force, enhancing the stability and reliability of the entire rotor structure. The coordinated design of the inner and outer stop structures simplifies alignment and fixing operations during motor assembly, reduces assembly errors, and makes the assembly of the entire rotor more convenient and efficient. This contributes to improving production automation and reducing production costs.

[0075] In this embodiment, the second lateral protrusion 21 of the axial connecting portion 23 effectively fixes the position of the outer rotor core 6 through its radially outer stop, enhancing the structural stability of the rotor assembly and the integrity of the magnetic circuit, thereby improving the efficiency and reliability of the motor. The injection molding width L3 of the outer circle of the axial connecting portion 23 is greater than the width L4 of the tangential ferrite 2 in the middle part, which can effectively fix and limit the outer rotor core 6 in the circumferential direction. The plastic coating of the plastic housing 1 at the upper and lower ends in the axial direction can fix and limit the axial plastic magnetic disk 4, forming the final plastic-coated outer rotor.

[0076] In one embodiment, the axial height of the tangential ferrite 2 is higher than the axial height of the outer rotor core 6, and the axial magnetic disk 4 is provided with a positioning groove 26 on the side facing the tangential ferrite 2, and the part of the tangential ferrite 2 extending out of the outer rotor core 6 is inserted into the positioning groove 26.

[0077] The portion of the tangential ferrite 2 that protrudes above the outer rotor core 6 engages with the positioning slot 26 on the axial plastic magnetic disk 4, providing additional axial positioning and fixing points. This ensures the stability of the tangential ferrite 2, preventing displacement due to vibration or high-speed rotation during motor operation and enhancing the structural stability between the magnetic material and the core. The protruding tangential ferrite 2 directly contacts the axial plastic magnetic disk 4, reducing air gaps in the magnetic circuit, increasing magnetic flux density, and optimizing the magnetic field distribution. This improves the motor's magnetic performance, output capacity, and efficiency. The positioning slot 26 simplifies the assembly process, ensuring quick and accurate assembly between the tangential ferrite 2 and the axial plastic magnetic disk 4, reducing assembly time, and improving production efficiency and consistency. The engagement of the positioning slot 26 with the tangential ferrite 2 disperses stress between the axial plastic magnetic disk 4 and the tangential ferrite 2, reducing the risk of material damage due to stress concentration and extending the motor's service life.

[0078] The above method enables a good fit and positioning structure between the tangential ferrite 2 and the axial plastic magnetic disk 4. Combined with the positioning of the tangential ferrite 2 and the outer rotor core 6 through the mounting groove 5, and the auxiliary positioning in the injection mold, the production process is relatively simple, can achieve a high degree of automation, and has high production efficiency.

[0079] In one embodiment, an injection groove 15 is provided on the outer periphery of the axial plastic magnetic disk 4, and the position of the injection groove 15 corresponds to the outer periphery of the ferrite 2 in the circumferential direction.

[0080] The injection groove 15 located on the outer periphery of the axial plastic magnetic disk 4 ensures that the plastic coating evenly wraps the tangential ferrite 2 and flows from the injection groove 15 to other positions, wrapping the outer rotor core 6 and the axial plastic magnetic disk 4, enhancing the bonding strength between them, while optimizing the magnetic circuit structure, reducing magnetic flux leakage, and improving the overall performance and operational stability of the motor.

[0081] Figure 1 and Figure 2The diagram shows a structural view of the rotor structure. Multiple outer rotor cores 6 are arranged circumferentially at intervals, with mounting grooves 5 formed between adjacent outer rotor cores 6 for mounting tangential ferrites 2. The tangential ferrites 2 are positioned within the mounting grooves 5, their axial height exceeding that of the outer rotor cores 6 to create a tangential magnetic field. Axial plastic magnetic disks 4 are positioned at both axial ends of the outer rotor cores 6, each with a positioning groove 26 for engaging the portion of the tangential ferrite 2 extending beyond the outer rotor core 6, ensuring precise alignment between the tangential ferrite 2 and the axial plastic magnetic disk 4, while simultaneously generating an axial magnetic field. A plastic-coated housing 1 encloses the outer rotor cores 6, tangential ferrites 2, and axial plastic magnetic disk 4, connecting these components into a single unit through injection molding, enhancing structural stability and durability. Furthermore, the injection grooves 15 of the plastic-coated housing 1 correspond to the outer periphery of the tangential ferrites 2, facilitating the filling of the injection material. This design results in a more rational magnetic field distribution, improving the efficiency and performance of the motor.

[0082] The plastic-coated housing 1 not only encapsulates the outer rotor core 6, but also fills the mounting gap between the outer rotor core 6 and the tangential ferrite 2, as well as the gap between the axial plastic magnetic disk 4 and the outer periphery of the tangential ferrite 2, through the injection-molded connecting layer 24, ensuring a tight connection between these components. Furthermore, the first lateral protrusion 25 extends circumferentially from the radially outer side of the outer rotor core 6, forming a radial stop against the tangential ferrite 2. The axial connecting portion 23 of the axial plastic magnetic disk 4 is correspondingly located on the outer periphery of the tangential ferrite 2, and extends radially outward to form a second lateral protrusion 21, forming a double radial stop with the first lateral protrusion 25, enhancing the structural stability. Through the injection molding process, these components are tightly integrated, improving the mechanical strength and operational performance of the entire rotor structure.

[0083] The outer rotor core 6 is formed by stacking rotor laminations.

[0084] In one embodiment, the rotor laminations are silicon steel sheets.

[0085] The outer rotor core 6 has a segmented structure, not a whole circular shape. When silicon steel sheets are used for stamping, they can be arranged in two or more rows, resulting in high material utilization and low motor material cost.

[0086] The outer rotor core 6 is formed by stamping and stacking multiple silicon steel sheets. The outer rotor core 6 has a first lateral protrusion 25 on both sides of its outer circle for positioning and limiting during the assembly of the tangential ferrite 2. During stamping and layout, the gap between the sheets in the same row is L1, and the gap between different rows is L2. Generally, L1 and L2 can be 1 to 2 mm.

[0087] In one embodiment, the rotor structure further includes an inner rotor core 7 and damping rubber 8. The plastic-coated housing 1 has a mounting through hole 9. A plurality of first protrusions 10 are circumferentially spaced on the inner wall of the mounting through hole 9. Second protrusions 11 are circumferentially spaced on the outer peripheral wall of the inner rotor core 7. A first groove 12 is formed between adjacent first protrusions 10, and a second groove 13 is formed between adjacent second protrusions 11. The first protrusions 10 are disposed in the second grooves 13 and form a filling gap 14 with the inner wall of the second grooves 13. The second protrusions 11 are disposed in the first grooves 12 and form a filling gap 14 with the inner wall of the first grooves 12. The damping rubber 8 is filled in the filling gap 14.

[0088] In this embodiment, the inner rotor core 7 is disposed within the mounting through hole 9 of the outer rotor core and is connected and fixed by the damping adhesive 8. The rotor structure of this embodiment includes a plastic-coated shell 1, a tangential ferrite 2, an axial plastic magnetic disk 4, an outer rotor core 6, an inner rotor core 7, and damping adhesive 8. Among them, the tangential ferrite 2 and the axial plastic magnetic disk 4 mainly serve as excitation sources, providing a stable permanent magnet field for the rotor; the outer rotor core 6 mainly serves as a magnetic conductor, exporting the magnetic field generated by the injection-molded permanent magnet and coupling it with the motor stator magnetic field; the inner rotor core 7 mainly serves as a torque transmitter, outputting the motor torque to the application end through cooperation with the motor rotor shaft; the damping adhesive 8 mainly serves to absorb electromagnetic vibration waves and buffer vibration.

[0089] See also Figure 15 and Figure 16 The diagram provides a perspective view of the rotor's internal structure, revealing the plastic-coated housing 1, tangential ferrite 2, axial plastic magnetic disk 4, outer rotor core 6, the connection between these components and the inner rotor core 7, as well as the distribution of the damping adhesive 8. The plastic-coated housing 1 has mounting through holes 9, and its inner wall has multiple first protrusions 10 evenly distributed circumferentially. Correspondingly, second protrusions 11 are arranged on the outer peripheral wall of the inner rotor core 7. Each second protrusion 11 corresponds to a first groove 12, and each first protrusion 10 corresponds to a second groove 13. The first protrusions 10 are embedded in the second grooves 13, and the second protrusions 11 are embedded in the first grooves 12. This staggered interlocking structure not only enhances the mechanical connection between the plastic-coated housing 1 and the inner rotor core 7 but also provides a filling gap 14, offering a channel for the injection of the damping adhesive 8. The damping adhesive 8 fills these gaps, forming an effective vibration isolation layer that can absorb the stress caused by vibration during motor operation, reduce noise, and improve the smoothness of motor operation.

[0090] The outer rotor core 6 is evenly distributed around the rotor along the circumferential direction. The number of outer rotor cores 6 is Z1 = 2 * P, where P is the number of pole pairs of the rotor. Tangential ferrite 2 is evenly distributed between the outer rotor cores 6, and its number is equal to the number of outer rotor cores 6. There are two axial plastic magnetic disks 4, symmetrically distributed at the upper and lower ends of the outer rotor cores 6. The plastic-coated shell 1 is injection molded to wrap and fix the axial plastic magnetic disks 4, the outer rotor cores 6, and the tangential ferrite 2 to form the outer rotor structure of this rotor structure, and a mounting through hole 9 is left on its inner side. The inner rotor core 7 is placed in the mounting through hole 9 of the outer rotor structure. The damping adhesive 8 is injected into the gap between the outer rotor structure and the inner rotor core 7 and wraps the two in the axial direction to increase the bonding strength.

[0091] The damping adhesive 8 filled in the gaps forms a three-dimensional interlocking and limiting structure, which not only enhances the bonding between the inner rotor core 7 and the plastic-coated housing 1 in the axial, radial, and tangential directions, but also effectively reduces stress concentration when transmitting torque or subjected to external impact, preventing damage to the damping structure and improving the overall strength and reliability of the structure. The fit between the first protrusion 10 on the inner wall of the mounting through hole 9 and the second protrusion 11 on the inner rotor core 7 not only helps to position the inner rotor core 7, but also ensures the uniform distribution of the damping adhesive 8 during injection molding, thereby achieving the best damping effect.

[0092] In one embodiment, the outer rotor core 6 has a first positioning hole 16 extending axially through it. The first positioning hole 16 is a non-circular hole and is filled with damping adhesive 8. By providing the non-circular first positioning hole 16 for mounting and positioning the outer rotor core 6, rotation of the individual outer rotor core 6 can be effectively prevented during the injection molding of the plastic-coated housing 1, ensuring the structural stability of the outer rotor core 6 during the injection molding process and guaranteeing the injection molding quality of the plastic-coated housing 1. In one embodiment, the first positioning hole 16 is a polygonal hole, such as a square or pentagonal hole.

[0093] After the positioning injection molding of the plastic-coated housing 1 is completed, the damping adhesive 8 can be filled into the first positioning hole 16, thereby using the damping adhesive 8 to further enhance the bonding strength between the outer rotor core 6 and the plastic-coated housing 1, and at the same time, it can also form an effective damping effect.

[0094] In one embodiment, the inner rotor core 7 has an axially oriented injection hole 17, which is filled with damping adhesive 8.

[0095] By creating injection holes 17 on the inner rotor core 7 and filling the holes with damping adhesive 8, the motor's vibration damping performance and overall strength are effectively improved. The design of the injection holes 17 not only provides a path for the filling of the damping adhesive 8, ensuring its uniform distribution within the rotor structure, but also further strengthens the bond between the inner rotor core 7 and the outer rotor structure, preventing adhesive detachment during high-speed operation or impact, thus enhancing the overall stability of the rotor. Furthermore, the uniformly distributed damping adhesive 8 can more effectively absorb vibrations and noise generated during motor operation, achieving low-vibration, low-noise operation of the motor.

[0096] In one embodiment, both the first positioning hole 16 and the injection hole 17 are filled with damping adhesive 8. The outer end face of the plastic-coated housing 1 is provided with damping adhesive 8. The axial plastic magnetic disk 4 is provided with a third positioning hole 18 through the first positioning hole 16 in the circumferential direction. The third positioning hole 18 is a non-circular hole. The plastic-coated housing 1 is provided with a flow hole 27 corresponding to the third positioning hole 18. The damping adhesive 8 flows into the first positioning hole 16 through the flow hole 27 and the third positioning hole 18. The flow hole 27, the first positioning hole 16, the injection hole 17, the outer end face of the axial plastic magnetic disk 4 and the damping adhesive 8 in the third positioning hole 18 are an integral structure, and the damping adhesive 8 forms a cage-like structure.

[0097] In this embodiment, the damping adhesive 8 not only fills the first positioning hole 16 and the injection hole 17, but also forms a covering layer on the outer end face of the axial plastic magnetic disk 4 and the plastic-coated housing 1. These filling positions are connected through the third positioning hole 18 and the flow hole 27, forming an integrated cage-like structure. The cage-like structure forms a continuous adhesive layer in the radial, tangential, and axial directions, effectively connecting the inner rotor core 7, the outer rotor core 6, and the components within the plastic-coated housing 1 tightly. This improves the bonding strength between these key components and ensures the structural stability of the rotor during high-speed operation or when subjected to external impact. The integrated damping adhesive 8 can be more evenly distributed throughout the rotor structure, absorbing vibration energy caused by electromagnetic excitation force and effectively buffering radial, tangential, and axial vibration waves generated between the outer rotor structure and the inner rotor core 7 during motor operation. This reduces motor operating noise, improves the overall damping effect, and ensures smooth motor operation.

[0098] By providing a third positioning hole 18 on the axial plastic magnetic disk 4, the damping adhesive 8 can flow into the first positioning hole 16 through the third positioning hole during injection molding. This ensures accurate filling of the damping adhesive at critical locations, simplifies the assembly process, reduces positional deviations caused by multi-step assembly, and improves the consistency and reliability of motor performance. The third positioning hole 18 adopts the same non-circular hole structure as the first positioning hole 16, allowing it to mate with the first positioning hole 16 on the outer rotor core 6 during injection molding to position the outer rotor core 6. The cage-like structure of the damping adhesive 8 is formed in one step through injection molding, reducing material costs and assembly time, while also avoiding additional connectors and lowering production costs. The integrated adhesive layer formed on the first positioning hole 16, the injection hole 17, and the outer end face of the axial plastic magnetic disk 4 provides better support and fixation for the magnetic material, improving material utilization.

[0099] In one embodiment, a recessed groove is provided on the radially inner part of the axial end face of the plastic-coated housing 1, and the damping adhesive 8 is filled in the recessed groove. Without affecting the axial height and axial magnetic field strength of the axial plastic magnetic disk 4, it is more convenient to form an integrated adhesive injection structure with the inner rotor core 7 located on the radially inner circumference of the plastic-coated housing 1, and it is more convenient to realize the connection and fixation between the inner rotor core 7 and the outer rotor structure.

[0100] In one embodiment, each side of the first protrusion 10 is parallel to the corresponding side of the second groove 13, and each side of the second protrusion 11 is parallel to the corresponding side of the first groove 12.

[0101] The parallel side engagement structure ensures precise alignment and a secure connection between the inner rotor core 7 and the plastic-coated housing 1. This design effectively reduces relative slippage during torque transmission, improving the rotor's tangential positioning accuracy. Furthermore, the parallel side contact evenly distributes contact pressure, avoiding stress concentration and thus reducing material wear and potential structural failure risks, increasing the rotor's reliability and lifespan. During motor operation, this engagement limiting structure effectively suppresses vibration and noise. By limiting radial and tangential displacement, it enhances the motor's smooth operation and quietness, further improving overall motor performance and user experience.

[0102] In one embodiment, the damping adhesive 8 filling the filling gap 14 is continuous in the circumferential direction, isolating and connecting the plastic-coated housing 1 and the inner rotor core 7.

[0103] The damping adhesive 8, filled in the circumferentially continuous filling gap 14, effectively isolates and connects the plastic-coated housing 1 and the inner rotor core 7, enhancing the structural stability and damping effect of the rotor, while ensuring synchronous rotation between the two components, thus improving the smoothness and efficiency of motor operation.

[0104] In one embodiment, the inner rotor core 7 has a central shaft hole 19, and a second positioning hole 20 is provided on the inner wall of the central shaft hole 19 to position the circumferential relative position of the inner rotor core 7 and the plastic-coated housing 1.

[0105] The second positioning hole 20, located on the inner wall of the central shaft hole 19 of the inner rotor core 7, ensures precise circumferential positioning between the inner rotor core and the plastic-coated housing 1. This ensures that the inner rotor core is centered within the mounting through hole 9 of the outer rotor structure, effectively improving the assembly accuracy and operational stability of the rotor assembly. It also makes the distribution of the damping rubber 8 within the filling gap 14 more uniform, thereby improving the overall performance and efficiency of the motor.

[0106] In one embodiment, the tangential ferrite 2 and the axial plastic magnetic disk 4 are formed on the same outer rotor core 6 with the same polarity, and the polarities of two adjacent outer rotor cores 6 in the circumferential direction are opposite.

[0107] The tangential ferrite 2 and the axial plastic magnetic disk 4 form a single outer rotor core 6 with the same polarity, while the polarities of two adjacent outer rotor cores 6 along the circumferential direction are opposite. This magnetic pole arrangement can generate a more complex and efficient magnetic field distribution, significantly enhancing the magnetic flux path of the motor. Specifically, the excitation sources with the same polarity work synergistically on the same outer rotor core 6, enhancing the magnetic field strength in that region, thereby improving the electromagnetic torque and power density of the motor. The design of adjacent outer rotor cores 6 with opposite polarities promotes the alternating flow of magnetic flux, optimizes the motor's magnetic circuit, reduces magnetic flux leakage and loss, and thus improves the motor's efficiency and operating performance. Furthermore, this magnetic pole layout can effectively suppress vibration and noise during motor operation. Through the balancing effect of magnetic forces, it reduces the unbalanced force of the rotor, enhances the motor's smoothness and quietness, and improves the user experience.

[0108] In one embodiment, the maximum distance D1 between the outer periphery of the outer rotor core 6 and the central axis of the plastic-coated housing 1 is greater than or equal to the maximum distance D2 between the outer periphery of the plastic-coated housing 1 and the central axis of the plastic-coated housing 1.

[0109] In this embodiment, the maximum distance D1 between the outer periphery of the outer rotor core 6 and the central axis of the plastic-coated housing 1 forms the maximum outer diameter of the outer rotor structure, and the maximum distance D2 between the outer periphery of the plastic-coated housing 1 and the central axis of the plastic-coated housing 1 forms the maximum outer diameter of the plastic-coated housing 1. By limiting D2≤D1, the problem of burrs caused by poor injection molding causing the outer rotor structure to rub against the stator can be effectively avoided, thereby improving the operational reliability of the rotor structure.

[0110] In one embodiment, the thickness L5 of the damping adhesive 8 between the inner rotor core 7 and the plastic-coated housing 1 is ≥0.5mm, the thickness L6 of the damping adhesive 8 at the outer end of the axial plastic magnetic disk 4 is ≥1mm, and the overlap dimension L7 between the inner rotor core 7 and the plastic-coated housing 1 in the tangential direction is ≥1mm.

[0111] By ensuring that the thickness L5 of the damping adhesive 8 between the inner rotor core 7 and the plastic-coated shell 1 is ≥0.5mm, the thickness L6 of the damping adhesive at the outer end of the axial plastic magnetic disk 4 is ≥1mm, and the overlap dimension L7 of the two along the tangential direction is ≥1mm, the damping effect and the connection strength of the damping adhesive 8 are effectively guaranteed, the damping effect and structural stability of the rotor structure are enhanced, and sufficient torque transmission efficiency is guaranteed at the same time.

[0112] In one embodiment, the maximum diameter of the rotor's outer circle is D1, and the diameter of the mounting through hole 9 is D3, where 0.25*D1≤D3≤0.5*D1.

[0113] By controlling the diameter D3 of the mounting through hole 9 to be between 25% and 50% of the maximum outer diameter D1 of the rotor, the magnetic circuit design and mechanical strength of the motor rotor are optimized, ensuring that the motor has good structural stability and resistance to external impact while achieving efficient energy conversion, thereby improving the overall performance and reliability of the motor.

[0114] In one embodiment, the axial thickness of the axial plastic magnetic disk 4 is L8, and the total axial thickness of the rotor structure is L9, where 0.1*L9≤L8≤0.4*L9.

[0115] The axial thickness L8 of the axial plastic magnetic disk 4 is set between 10% and 40% of the total axial thickness L9 of the rotor structure, which effectively balances the axial magnetic flux density of the motor with the overall structural compactness, improves the electromagnetic performance and operational stability of the motor, and reduces material costs, thus achieving a dual optimization of motor efficiency and economy.

[0116] According to an embodiment of the present invention, the above-mentioned method for forming the rotor structure includes: preparing an axial magnetic disk 4 by injection molding; stacking multiple rotor laminations to form an outer rotor core 6; placing the axial magnetic disk 4 into a mold and fixing it; installing and fixing multiple outer rotor cores 6 on the axial magnetic disk 4; installing and positioning tangential ferrite in the mounting groove between adjacent outer rotor cores; injecting plastic into the mold to encapsulate the axial magnetic disk 4, the outer rotor core 6, and the tangential ferrite 2 into an integral structure to form an outer rotor structure, and performing magnetization orientation of the outer rotor structure.

[0117] The above molding method first forms an axial magnetic disk 4 through injection molding. Then, multiple rotor laminations are stacked to form multiple outer rotor cores 6. The axial magnetic disk is placed in a mold and fixed. Next, the multiple outer rotor cores 6 are placed in the mold, and each outer rotor core 6 is fixed to the axial magnetic disk 4 using the first positioning hole 16 and the third positioning hole 18. Then, tangential ferrite is installed and positioned in the mounting grooves between adjacent outer rotor cores. Finally, plastic is injected into the mold to encapsulate the axial magnetic disk 4, outer rotor cores 6, and tangential ferrite 2 into a single outer rotor structure, and the outer rotor structure is magnetized and oriented. In this molding method, the outer rotor core 6 is placed on the axial magnetic disk and precisely positioned. Because the first positioning hole 16 and the third positioning hole 18 are non-circular holes with identical structures, the outer rotor core 6 is limited on the axial magnetic disk, preventing rotation and ensuring the accuracy of the magnetic pole position. By injecting plastic into the mold and wrapping it around the axial plastic magnetic disk 4, the outer rotor core 6, and the tangential ferrite 2, not only is a tight connection of materials achieved, eliminating gaps and magnetic circuit discontinuities that may occur in traditional assembly, but the magnetization and orientation of the permanent magnets are also completed during the injection molding process. This avoids the increased assembly difficulty caused by like pole repulsion, reduces assembly difficulty, improves assembly efficiency, and effectively ensures the consistency and strength of the magnetic field, further enhancing the motor's performance. The integrated injection molding process also reduces assembly steps, lowers production costs, and improves the reliability and durability of the rotor structure. The injection molding material effectively fills the tiny gaps between components, thus enhancing overall mechanical strength and reducing vibration and noise during operation.

[0118] In one embodiment, the molding method further includes: placing the inner rotor core into a mold and defining the relative position of the inner rotor core and the outer rotor structure; injecting damping adhesive into the mold to wrap the outer rotor structure and the inner rotor core together.

[0119] The method of precisely placing the inner rotor core 7 and defining its relative position with the outer rotor structure, then injecting damping adhesive 8 into the mold to wrap the two together, effectively enhances the structural stability and damping performance of the rotor, while simplifying the assembly process and ensuring the smoothness and quietness of the motor operation.

[0120] In one embodiment, the step of placing the outer rotor core into the mold and positioning it includes: placing the outer rotor core into the axial plastic magnetic disk 4 through the first positioning hole for positioning.

[0121] The step of precisely placing and fixing the outer rotor core 6 in the axial plastic magnetic disk 4 through the first positioning hole 16 ensures accurate alignment of the magnetic poles and geometric consistency of the rotor structure, effectively guaranteeing the structural accuracy and molding quality of the outer rotor structure and improving injection molding efficiency.

[0122] According to an embodiment of the present invention, the motor includes a stator structure and a rotor structure, wherein the rotor structure is the rotor structure described above, and the stator structure is sleeved on the outer periphery of the rotor structure.

[0123] 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.

[0124] It should be noted that the terms "first," "second," etc., used 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 in sequences other than those illustrated or described herein.

[0125] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rotor structure, characterized in that, include: The outer rotor core (6) is arranged at intervals along the circumference, and an mounting groove (5) is formed between adjacent outer rotor cores (6). A tangential ferrite (2) is disposed in the mounting groove (5) and is used to form a tangential magnetic field; An axial magnetic disk (4) is disposed at both ends of the outer rotor core and is used to form an axial magnetic field; A plastic-coated shell (1) is used to wrap the outer rotor core (6), the tangential ferrite (2) and the axial plastic magnetic disk (4), and the outer rotor core (6), the tangential ferrite (2) and the axial plastic magnetic disk (4) are injection molded into one piece.

2. The rotor structure according to claim 1, characterized in that, There is an installation gap between the outer rotor core and the tangential ferrite. The plastic-coated housing (1) includes an end connection (22) wrapped around the axial plastic magnetic disk (4), an axial connection (23) connected to the radially outer side of the end connection (22), an inner ring connection (3) connected to the radially inner side of the end connection (22), and an injection-molded connection layer (24) filled in the installation gap.

3. The rotor structure according to claim 2, characterized in that, The outer rotor core (6) extends radially outward to both sides to form a first lateral protrusion (25), which forms a radial stop on the tangential ferrite (2).

4. The rotor structure according to claim 3, characterized in that, The axial connecting portion (23) is correspondingly disposed on the outer peripheral side of the tangential ferrite (2). The radially outer side of the axial connecting portion (23) extends to both sides in the circumferential direction to form a second lateral protrusion (21). The first lateral protrusion (25) is located on the radially inner side of the second lateral protrusion (21), and a radial stop is formed by the second lateral protrusion (21).

5. The rotor structure according to claim 1, characterized in that, The axial height of the tangential ferrite (2) is higher than the axial height of the outer rotor core (6). The axial plastic magnetic disk (4) is provided with a positioning groove (26) on the side facing the tangential ferrite (2). The part of the tangential ferrite (2) extending out of the outer rotor core (6) is inserted into the positioning groove (26).

6. The rotor structure according to claim 1, characterized in that, The axial plastic magnetic disk (4) has an injection groove (15) on its outer periphery, and the position of the injection groove (15) corresponds to the outer periphery of the tangential ferrite (2).

7. The rotor structure according to claim 1, characterized in that, The rotor structure also includes an inner rotor core (7) and damping rubber (8). The plastic-coated shell (1) has a mounting through hole (9). A plurality of first protrusions (10) are arranged circumferentially on the inner wall of the mounting through hole (9). A second protrusion (11) is arranged circumferentially on the outer peripheral wall of the inner rotor core (7). A first groove (12) is formed between adjacent first protrusions (10). A second groove (13) is formed between adjacent second protrusions (11). The first protrusions (10) are disposed in the second groove (13) and form a filling gap (14) with the inner wall of the second groove (13). The second protrusions (11) are disposed in the first groove (12) and form the filling gap (14) with the inner wall of the first groove (12). The damping rubber (8) fills the filling gap (14).

8. The rotor structure according to claim 7, characterized in that, The outer rotor core (6) is provided with a first positioning hole (16) through it along the axial direction. The first positioning hole (16) is a non-circular hole and is filled with the damping adhesive (8). And / or, the inner rotor core (7) is provided with an injection hole (17) along the axial direction and is filled with the damping adhesive (8).

9. The rotor structure according to claim 8, characterized in that, The first positioning hole (16) and the glue injection hole (17) are both filled with the damping glue (8). The damping glue (8) is provided on the outer end face of the axial plastic magnetic disk (4). A third positioning hole (18) is provided on the axial plastic magnetic disk (4) in a circumferential manner corresponding to the first positioning hole (16). The third positioning hole (18) is a non-circular hole. The damping glue (8) flows into the first positioning hole (16) through the third positioning hole (18). The first positioning hole (16), the glue injection hole (17), the outer end face of the axial plastic magnetic disk (4) and the damping glue (8) in the third positioning hole (18) are an integral structure. The damping glue (8) forms a cage-like structure.

10. The rotor structure according to claim 7, characterized in that, The inner rotor core (7) has a central shaft hole (19), and a second positioning hole (20) is provided on the inner wall of the central shaft hole (19) to position the inner rotor core (7) and the plastic-coated shell (1) in a circumferential relative position.

11. The rotor structure according to any one of claims 1 to 10, characterized in that, The tangential ferrite (2) and the axial plastic magnetic disk (4) are formed on the same outer rotor core (6) with the same polarity, and the polarities of two adjacent outer rotor cores (6) in the circumferential direction are opposite.

12. The rotor structure according to any one of claims 1 to 10, characterized in that, The maximum distance between the outer periphery of the outer rotor core (6) and the central axis of the plastic-coated shell (1) is greater than or equal to the maximum distance between the outer periphery of the tangential ferrite (2) and the central axis of the plastic-coated shell (1).

13. The rotor structure according to any one of claims 7 to 10, characterized in that, The thickness of the damping adhesive (8) between the inner rotor core (7) and the plastic-coated shell (1) is L5≥0.5mm, the thickness of the damping adhesive (8) at the outer end of the axial plastic magnetic disk (4) is L6≥1mm, and the overlap dimension of the inner rotor core (7) and the plastic-coated shell (1) in the tangential direction is L7≥1mm.

14. The rotor structure according to any one of claims 7 to 10, characterized in that, The maximum diameter of the outer circle of the rotor is D1, and the diameter of the mounting through hole (9) is D3, 0.25*D1≤D3≤0.5*D1.

15. The rotor structure according to any one of claims 1 to 10, characterized in that, The axial thickness of the axial plastic magnetic disk (4) is L8, and the total axial thickness of the rotor structure is L9, 0.1*L9≤L8≤0.4*L9.

16. A method for forming a rotor structure as described in any one of claims 1 to 15, characterized in that, include: Fabrication of axial plastic magnetic disks; Multiple rotor laminations are stacked together to form the outer rotor core; Place the axial plastic magnetic disk into the mold and fix it in place; Multiple external rotor cores are mounted and fixed on an axial plastic magnetic disk. The tangential ferrite is installed and positioned in the mounting slot between adjacent outer rotor cores; Plastic is injected into the mold to encapsulate the axial plastic magnetic disk, the outer rotor core, and the tangential ferrite into an outer rotor structure, and the outer rotor structure is then magnetized and oriented.

17. The molding method according to claim 16, characterized in that, Molding methods also include: The inner rotor core is placed into the mold, and the relative positions of the inner rotor core and the outer rotor structure are defined. Shock-absorbing adhesive is injected into the mold to encapsulate the outer rotor structure and the inner rotor core into one unit.

18. The molding method according to claim 16, characterized in that, The steps for placing and positioning the outer rotor core into the mold include: The outer rotor core is placed into the axial plastic magnetic disk for positioning through the first positioning hole.

19. An electric motor, comprising a stator structure and a rotor structure, characterized in that, The rotor structure is the rotor structure according to any one of claims 1 to 15, and the stator structure is sleeved on the outer periphery of the rotor structure.

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