Rotor structure and permanent magnet servo motor
By employing a conical fit and a tightening structure to clamp the iron core module in the rotor structure, the problems of high processing cost and insufficient thermal stability of traditional rotor structures are solved, achieving simple and efficient assembly and stable motor operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HANLINZE ENVIRONMENTAL PROTECTION TECHNOLOGY (GUANGDONG) CO LTD
- Filing Date
- 2025-06-16
- Publication Date
- 2026-05-22
AI Technical Summary
The rotor structure of traditional permanent magnet synchronous motors suffers from high cost and low efficiency during processing and assembly, and its thermal stability is insufficient. It is also prone to module misalignment due to thermal expansion or processing tolerances, which affects motor performance.
The front and rear truncated cones on the rotating shaft engage with the conical surfaces of the pressure plate, and the core module is clamped by a tightening structure to form a conical mating pair. This generates both radial and axial constraint forces, ensuring the stable fixation of the core module on the rotor.
It simplifies the assembly process, improves assembly quality and efficiency, reduces dynamic balance correction, prevents core module misalignment, ensures stable operation of the motor under complex working conditions, and enhances overall reliability and performance.
Smart Images
Figure CN224267090U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor technology, and in particular to a rotor structure and a permanent magnet servo motor. Background Technology
[0002] In the rotor structure of a traditional permanent magnet synchronous motor, the rotor core is composed of multiple core modules. The assembly of these core modules mainly relies on the following two technical solutions:
[0003] The first approach uses a keyway fit structure. Keyways are milled on the rotor shaft, and corresponding key protrusions are set on the core modules. A hydraulic press is then used to press the modules one by one into the shaft. While the keyway and key fit completely eliminates the risk of module misalignment, this method has significant drawbacks: the keyway machining process is complex, costly, and time-consuming; during multi-module assembly, accumulated errors can increase the amount of dynamic balance correction, requiring additional compensation for imbalance; furthermore, the keyway structure weakens the shaft strength, potentially affecting overall reliability.
[0004] The second approach employs an interference-fit circular structure, where the modules are fixed by an interference fit between the circular shaft and the inner hole of the iron core. This eliminates the need for keyway machining, reduces production costs, simplifies the assembly process, and improves dynamic balance. However, this approach has stringent machining tolerance requirements. If the shaft or iron core experiences dimensional deviations due to mold wear, or if the rotor heats up and causes thermal expansion during motor operation, the constraint force of the interference fit may be insufficient to resist the tangential forces between the modules, ultimately leading to module misalignment. This results in uneven magnetic fields or even mismagnetism, severely impacting motor performance. In existing technologies, while the keyway structure avoids misalignment, it sacrifices economy and machining efficiency, while the interference fit structure simplifies the process but suffers from insufficient thermal stability.
[0005] It is evident that existing technologies still need improvement and enhancement. Utility Model Content
[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a rotor structure and permanent magnet servo motor that can avoid the processing cost of keyway and ensure the stability of rotor module under thermal expansion or tolerance fluctuation.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] A rotor structure includes a rotating shaft, a front pressure plate and a rear pressure plate sleeved on the rotating shaft, and a plurality of iron core modules sleeved on the rotating shaft and located between the front pressure plate and the rear pressure plate. The front pressure plate and the rear pressure plate clamp the plurality of iron core modules by a tightening structure, so that the plurality of iron core modules are tightly connected along the axial direction to form a rotor core. A front truncated cone portion and a rear truncated cone portion are formed on the rotating shaft. A first conical hole that cooperates with and is positioned on the front truncated cone portion is formed on the front pressure plate, and a second conical hole that cooperates with and is positioned on the rear pressure plate.
[0009] As a further improvement to the above technical solution, a circular shaft portion is formed on the rotating shaft between the front truncated cone portion and the rear truncated cone portion, and an inner circular hole with an interference fit to the circular shaft portion is formed on the iron core module.
[0010] As a further improvement to the above technical solution, the outer diameter of the front truncated cone is larger than that of the round shaft and the outer diameter of the front truncated cone gradually decreases in the direction away from the round shaft, so that a slatted step is formed at the connection between the front truncated cone and the round shaft for axial positioning of the rotor core.
[0011] As a further improvement to the above technical solution, the slope of the front truncated cone is 5° to 8°.
[0012] As a further improvement to the above technical solution, the maximum outer diameter of the rear truncated cone portion is equal to the outer diameter of the circular shaft portion, and the outer diameter of the rear truncated cone portion gradually decreases in the direction away from the circular shaft portion.
[0013] As a further improvement to the above technical solution, the slope of the rear truncated cone is 3° to 5°.
[0014] As a further improvement to the above technical solution, the tightening structure includes multiple tightening screws arranged in a circumferential array and passing through the rotor core, the front pressure plate and the rear pressure plate along the axial direction, and the rear end of the tightening screw is threaded with a tightening nut.
[0015] As a further improvement to the above technical solution, the head of the tightening screw is a hexagonal head, the front pressure plate has a hexagonal hole that fits into the head of the tightening screw, and the rear pressure plate has a through hole through which the tightening screw passes.
[0016] This utility model also provides a permanent magnet servo motor, including the rotor structure described above.
[0017] The beneficial effects of this utility model are as follows: The rotor structure provided by this utility model abandons the traditional keyway structure, avoiding weakening of the shaft's mechanical strength. The front and rear truncated cone portions on the shaft can be completed by turning. Through the positioning of the front and rear pressure plates with the shaft's conical surface, and the clamping of the core module by the tightening structure, the assembly process is simpler and more precise. This reduces the amount of dynamic balance correction caused by accumulated errors in multi-module assembly, lowers the need for additional dynamic balance compensation, and improves assembly quality and efficiency. The rotor structure utilizes the radial constraint force generated by the conical surface fit to effectively address dimensional deviations in the shaft or core caused by mold wear, as well as thermal expansion problems caused by rotor heating during motor operation. Attached Figure Description
[0018] Figure 1 A cross-sectional view of the rotor structure provided by this utility model.
[0019] Figure 2 An exploded view of the rotor structure provided by this utility model.
[0020] Figure 3 A perspective view of the rotating shaft provided by this utility model.
[0021] Figure 4 The three-dimensional rotor structure provided by this utility model Figure 1 .
[0022] Figure 5 The three-dimensional rotor structure provided by this utility model Figure 2 .
[0023] Explanation of main component symbols: 1-rotating shaft, 11-front truncated cone, 12-round shaft, 13-rear truncated cone, 14-stepping edge, 2-front pressure plate, 21-first cone hole, 22-hexagonal hole, 3-rear pressure plate, 31-second cone hole, 32-through hole, 4-rotor core, 41-core module, 42-inner circular hole, 5-tightening structure, 51-tightening screw, 52-tightening nut. Detailed Implementation
[0024] This utility model provides a rotor structure and a permanent magnet servo motor. To make the purpose, technical solution, and effects of this utility model clearer and more explicit, the following describes this utility model in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit the scope of protection of this utility model.
[0025] Please see Figures 1 to 5This utility model provides a rotor structure, including a rotating shaft 1, a front pressure plate 2 and a rear pressure plate 3 sleeved on the rotating shaft 1, and a plurality of iron core modules 41 sleeved on the rotating shaft 1 and located between the front pressure plate 2 and the rear pressure plate 3. The front pressure plate 2 and the rear pressure plate 3 clamp the plurality of iron core modules 41 by a tightening structure 5, so that the plurality of iron core modules 41 are tightly connected along the axial direction to form a rotor iron core 4. A front truncated cone portion 11 and a rear truncated cone portion 13 are formed on the rotating shaft 1. A first conical hole 21 is formed on the front pressure plate 2 to cooperate and be positioned with the front truncated cone portion 11, and a second conical hole 31 is formed on the rear pressure plate 3 to cooperate and be positioned with the rear truncated cone portion 13.
[0026] The rotor structure forms a conical mating pair through the front truncated cone portion 11 of the shaft 1 and the first conical hole 21 of the front pressure plate 2, and the rear truncated cone portion 13 and the second conical hole 31 of the rear pressure plate 3. This conical mating method can generate a radial component force when the tightening structure 5 applies axial force. When the tightening structure 5 applies axial pressure, the front pressure plate 2 and the rear pressure plate 3 squeeze the iron core module 41 axially, generating an axial preload between the modules. The conical mating has a self-centering characteristic, ensuring the radial positioning accuracy of the pressure plate and the shaft 1, while the axial clamping force is converted into a radial constraint force between the inner hole of the iron core module 41 and the shaft 1. The combined action of this radial constraint force and the axial clamping force firmly fixes the iron core module 41 to the shaft 1, ensuring that the iron core module 41 will not be misaligned or loosened due to tangential force, thermal expansion, or machining tolerances during high-speed rotation of the rotor, thus ensuring the stable operation of the rotor structure.
[0027] The rotor structure provided by this utility model abandons the traditional keyway structure, avoiding weakening of the shaft's mechanical strength. The truncated conical part of the shaft 1 can be completed by turning. Through the positioning of the front pressure plate 2, rear pressure plate 3, and the conical surface of the shaft 1, and the clamping of the core module 41 by the tightening structure 5, the assembly process is simpler and more precise. This reduces the amount of dynamic balance correction caused by the cumulative error of assembling multiple core modules 41, lowers the need for additional dynamic balance compensation, and improves assembly quality and efficiency. The rotor structure utilizes the radial constraint force generated by the conical surface fit to effectively address dimensional deviations in the shaft or core caused by mold wear, as well as thermal expansion problems caused by rotor heating during motor operation. Even under these conditions, the constraint force generated by the conical surface fit is sufficient to resist the tangential force between modules, preventing misalignment of the core module 41 and avoiding uneven magnetic field or mismagnetic phenomena, thereby ensuring stable motor performance and improving the overall reliability and stability of the rotor structure.
[0028] Specifically, a circular shaft portion 12 is formed on the rotating shaft 1 between the front truncated cone portion 11 and the rear truncated cone portion 13, and an inner circular hole 42 with an interference fit to the circular shaft portion 12 is formed on the core module 41. Based on the existing front pressure plate 2, rear pressure plate 3, and the conical surface fit between the rotating shaft 1 and the core module 41, and the clamping structure 5, the interference fit between the circular shaft portion 12 and the inner circular hole 42 of the core module 41 further enhances the connection strength between the core module 41 and the rotating shaft 1 radially. This dual constraint mechanism ensures reliable fixation of the core module 41 in both the axial and radial directions, greatly reducing the risk of loosening or displacement of the core module 41 due to vibration, centrifugal force, and other factors during motor operation, effectively improving the stability and reliability of the overall rotor assembly.
[0029] Furthermore, the outer diameter of the front truncated cone portion 11 is larger than that of the round shaft portion 12, and the outer diameter of the front truncated cone portion 11 gradually decreases in the direction away from the round shaft portion 12, so that a aligning step 14 is formed at the connection between the front truncated cone portion 11 and the round shaft portion 12 for axial positioning of the rotor core 4. During the process of pressing the core modules 41 one by one into the rotating shaft 1 using a hydraulic press, the aligning step 14 provides a precise reference for the axial pressing of the core modules 41. With the stable pressure output of the hydraulic press, the pressing depth of the core modules 41 can be precisely controlled by using the aligning step 14 as a reference during the pressing process, effectively avoiding axial positional deviations of the core modules 41 caused by excessive or insufficient pressing. This not only ensures the consistency of the position of each core module 41 on the rotating shaft 1, but also reduces the product defect rate caused by assembly errors, thus improving product quality.
[0030] Preferably, the slope of the front truncated cone portion 11 is 5° to 8°. With the slope of the front truncated cone portion 11 within the range of 5° to 8°, when the tightening screw 51 applies axial tension, the front truncated cone portion 11 and the conical surface of the first conical hole 21 can produce a good self-centering effect. This slope allows the axial tension to be efficiently converted into a uniform radial clamping force. Even with certain machining tolerances, such as a conical surface angle deviation of ±0.5°, the elastic deformation between the conical surfaces can automatically adjust for alignment, achieving precise axial positioning of the front pressure plate 2 along the axis of the rotating shaft 1, avoiding eccentricity problems, significantly improving the overall coaxiality of the rotor, and ensuring stable and efficient operation of the motor.
[0031] In this embodiment, the maximum outer diameter of the rear truncated cone portion 13 is equal to the outer diameter of the round shaft portion 12, and the outer diameter of the rear truncated cone portion 13 gradually decreases in the direction away from the round shaft portion 12, ensuring that the core module 41 can be pressed in from the rear end of the shaft. When the tightening screw 51 is tightened, the conical surface of the rear truncated cone portion 13 and the second conical hole 31 can produce a good self-centering effect. The rear truncated cone portion 13 and the second conical hole 31 form a stable constraint relationship, which, together with the constraints of the front truncated cone portion 11 and the front pressure plate 2, achieves bidirectional axial positioning and radial clamping of the rotor core 4. Even if the motor encounters strong vibration, impact, or drastic temperature changes during operation, the rear pressure plate 3 can be firmly fixed, effectively preventing axial movement or radial displacement of the rotor core 4, greatly enhancing the overall stability and reliability of the rotor structure, reducing the risk of failure caused by structural loosening, and extending the service life of the motor.
[0032] The slope of the rear truncated cone 13 is 3° to 5°. Compared to the slope of the front truncated cone 115° to 8°, this smaller slope is more suitable for withstanding axial impact loads from the rear end of the motor.
[0033] Specifically, the tightening structure 5 includes multiple tightening screws 51 arranged in a circumferential array and axially penetrating the rotor core 4, the front pressure plate 2, and the rear pressure plate 3. A tightening nut 52 is threaded to the rear end of each tightening screw 51. The multiple circumferentially arranged tightening screws 51 apply uniform and symmetrical axial pressure to the rotor core 4, the front pressure plate 2, and the rear pressure plate 3. This uniform force distribution effectively avoids localized stress concentration, preventing deformation and misalignment of the core module 41 due to uneven force distribution, as well as tilting of the front pressure plate 2 and the rear pressure plate 3. This ensures that the rotor maintains a stable and reliable structural state during high-speed rotation, improving the smoothness and reliability of motor operation.
[0034] The screw and nut connection method simplifies the assembly process. Workers can flexibly adjust the tightness of each tightening screw 51 according to actual needs, precisely controlling the clamping force on the rotor core 4 to avoid affecting rotor performance due to excessive or insufficient clamping force. Furthermore, during motor maintenance or component replacement, simply loosening the tightening nut 52 allows for quick disassembly of the front pressure plate 2, rear pressure plate 3, and core module 41, greatly improving the convenience of assembly and maintenance and reducing maintenance difficulty and time costs.
[0035] In this embodiment, four tightening screws 51 and four corresponding tightening nuts 52 are provided. The four tightening screws 51 are arranged in a circumferential array, which can form a stable quadrilateral force structure on the rotor core 4, the front pressure plate 2, and the rear pressure plate 3, so that the axial pressure is evenly distributed throughout the entire rotor cross section. When the motor rotates at high speed, this balanced force distribution can effectively counteract the influence of complex external forces such as centrifugal force and tangential force on the rotor structure, avoid local deformation or loosening caused by uneven force distribution, ensure that the core modules 41 are tightly fitted together, greatly improve the structural stability of the rotor during operation, and ensure the smooth and efficient operation of the motor.
[0036] Furthermore, the head of the tightening screw 51 is a hexagonal head, and the front pressure plate 2 has a hexagonal hole 22 that engages with the head of the tightening screw 51. This engagement design of the hexagonal head and the hexagonal hole 22 allows the tightening screw 51 to automatically align and restrict circumferential rotation during assembly. When tightening the nut with a torque wrench, the screw head forms a reliable circumferential constraint within the hexagonal hole 22, avoiding the slippage or free-spinning problems common with traditional screw heads. The design of the hexagonal hole 22 allows the screw head to be fully recessed into the surface of the front pressure plate 2, keeping the outer end face of the front pressure plate 2 flat. Compared to traditional protruding screw heads (such as cylindrical head screws), this design reduces axial space occupation and is more suitable for applications in motors sensitive to axial dimensions (such as servo motors and hub motors).
[0037] This utility model also provides a permanent magnet servo motor, including the rotor structure described in any of the above embodiments. Magnets are disposed in the rotor core 4, and bearings are respectively fitted at both ends of the rotating shaft 1. The rotor structure, through multiple constraint mechanisms such as conical fit, interference fit, and a rationally arranged tightening structure 5, effectively resists the influence of complex working conditions such as thermal expansion, vibration, and impact on the motor, reducing the risk of component loosening and wear. The stability of the core module 41 is effectively guaranteed, avoiding uneven magnetic field or mismagnetism caused by misalignment of the core module 41. This enables the motor to output more stable and precise torque and speed, effectively improving the motor's dynamic performance and control accuracy.
[0038] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0040] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this utility model, and all such substitutions or changes should fall within the protection scope of this utility model.
Claims
1. A rotor structure, characterized in that, The device includes a rotating shaft, a front pressure plate and a rear pressure plate fitted on the rotating shaft, and multiple iron core modules fitted on the rotating shaft and located between the front pressure plate and the rear pressure plate. The front pressure plate and the rear pressure plate clamp the multiple iron core modules through a tightening structure, so that the multiple iron core modules are tightly connected along the axial direction to form a rotor iron core. A front truncated cone portion and a rear truncated cone portion are formed on the rotating shaft. A first conical hole that cooperates with and is positioned on the front truncated cone portion is formed on the front pressure plate, and a second conical hole that cooperates with and is positioned on the rear pressure plate.
2. The rotor structure according to claim 1, characterized in that, A circular shaft portion is formed on the rotating shaft between the front truncated cone portion and the rear truncated cone portion, and an inner circular hole with an interference fit is formed on the iron core module.
3. The rotor structure according to claim 2, characterized in that, The outer diameter of the front truncated cone is larger than that of the round shaft, and the outer diameter of the front truncated cone gradually decreases in the direction away from the round shaft, so that a slatted step is formed at the connection between the front truncated cone and the round shaft for axial positioning of the rotor core.
4. The rotor structure according to claim 3, characterized in that, The slope of the front truncated cone is 5° to 8°.
5. The rotor structure according to claim 2, characterized in that, The maximum outer diameter of the truncated cone portion is equal to the outer diameter of the circular shaft portion, and the outer diameter of the truncated cone portion gradually decreases in the direction away from the circular shaft portion.
6. The rotor structure according to claim 5, characterized in that, The slope of the truncated cone is 3° to 5°.
7. The rotor structure according to claim 1, characterized in that, The tightening structure includes multiple tightening screws arranged in a circumferential array and passing through the rotor core, the front pressure plate and the rear pressure plate along the axial direction. The rear end of the tightening screw is threaded with a tightening nut.
8. The rotor structure according to claim 7, characterized in that, The head of the tightening screw is a hexagonal head, the front pressure plate has a hexagonal hole that fits into the head of the tightening screw, and the rear pressure plate has a through hole through which the tightening screw passes.
9. A permanent magnet servo motor, characterized in that, Including the rotor structure as described in any one of claims 1-8.