Centrifugal passive balance high-speed magnetic suspension flywheel energy storage device
Patent Information
- Application Number
- CN202611147148.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-30
- Publication Date
- 2026-11-03
AI Technical Summary
Existing flywheel energy storage devices suffer from problems such as insufficient dynamic balance adjustment capability, poor reliability of carbon fiber rim connection, and insufficient structural safety margin at high speeds, resulting in insufficient high-speed stability and reliability, making it difficult to achieve high speeds and high energy storage density.
By adopting a centrifugal passive balancing structure, through hub stiffness topology optimization, wave-shaped meshing composite interface and winding rim forming, combined with magnetic levitation shaft support, it achieves speed adaptive centrifugal self-locking, circumferential uniform clamping and passive dynamic balancing, forming a triple composite connection, reducing the control load and adjustment difficulty of magnetic levitation bearings.
It improves the stability and reliability of high-speed continuous operation of the flywheel rotor, extends its service life, reduces vibration and alternating stress, enhances structural safety and torque transmission reliability, and supports flywheel operation at higher speed levels.
Smart Images
Figure CN123034663A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flywheel energy storage technology, specifically relating to a centrifugal passive balance high-speed magnetic levitation flywheel energy storage device. Background Technology
[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.
[0003] Flywheel energy storage relies on the high-speed rotation of a flywheel rotor to achieve efficient bidirectional conversion between electrical and mechanical energy. It is a key technology and equipment for overcoming the volatility of new energy power generation, improving the frequency regulation accuracy of the power grid, and ensuring the reliability of power supply to critical loads.
[0004] As flywheel energy storage develops towards higher speeds and higher energy density, the structural reliability and high-speed stability of the rotor body have become the core bottlenecks restricting performance improvement. Currently, mainstream flywheel rotor solutions in the industry have significant technical shortcomings: The dynamic balance adjustment capability is insufficient. Existing flywheel rotors mostly rely on the precision dynamic balance calibration before leaving the factory. During operation, the imbalance caused by material creep and load fluctuation cannot be compensated in real time. The active balancing system has a complex structure, is difficult to control, and has low reliability, making it difficult to adapt to long-term high-speed continuous operation conditions.
[0005] Carbon fiber rim connections suffer from poor reliability and significant attenuation of interference fit at high speeds. This is because carbon fiber rims and metal hubs often use a simple smooth cylindrical surface interference fit. Under high-speed rotation, both the metal hub and the carbon fiber rim undergo radial expansion due to centrifugal force. Because traditional solid hubs have high radial stiffness, their expansion is often less than that of the carbon fiber rim. This results in a continuous decrease in preload at the mating surfaces as the speed increases, leading to insufficient interfacial friction and ultimately rim slippage and fit failure, severely limiting the flywheel's maximum operating speed.
[0006] The machining and assembly of integral wheel hubs is difficult. Large-diameter integral metal wheel hubs have long machining cycles, strict control of form and position tolerances, and low material utilization. During assembly, they need to be hoisted and connected as a whole, and the coaxiality calibration is cumbersome. If local damage occurs later, the whole hub needs to be replaced, resulting in extremely high maintenance costs.
[0007] Insufficient structural safety margin means that the wheel flange and hub rely solely on interfacial friction to transmit torque, without mechanical meshing redundancy and self-locking mechanism. Under extreme working conditions, relative slippage is likely to occur, leading to increased vibration or even structural failure. Summary of the Invention
[0008] To address the aforementioned issues, this invention proposes a centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device. Based on a high-rigidity magnetic levitation shaft system, it achieves speed-adaptive centrifugal self-locking, circumferential uniform clamping, passive real-time dynamic balancing, and modular assembly through structural and technological innovations such as hub stiffness topology optimization, wave-shaped meshing composite interface, wound rim forming, and passive dynamic balancing. This completely solves the industry pain point of the inability to balance the performance and manufacturability of high-speed flywheel rotors.
[0009] According to some embodiments, the present invention provides a centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device, which adopts the following technical solution: A centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device includes an energy storage device housing, an axial thrust bearing and a lower radial support assembly disposed at the bottom of the housing, a bottom shaft, a flywheel shaft, an energy storage flywheel rotor assembly fixed on the flywheel shaft, a central radial electromagnetic bearing, a motor stator, a motor rotor shaft, and an upper radial support assembly; wherein, the bottom end of the flywheel shaft and the top end of the bottom shaft, and the top end of the flywheel shaft and the bottom end of the motor rotor shaft are respectively connected by a cylindrical interference fit; the energy storage flywheel rotor assembly includes a split hub assembly, a carbon fiber rim, and a centrifugal passive balancing unit; the split hub assembly is formed by multiple hub discs stacked axially, and each hub disc is connected to the flywheel shaft via a spline. The hub assembly has a wavy meshing structure on its outer edge. The hub disc end face is symmetrically equipped with a weight-reducing structure along the circumference, ensuring that the radial expansion of the hub at rated speed is greater than the radial expansion of the carbon fiber rim, forming a centrifugal self-locking mechanism. The carbon fiber rim is cured and formed on the outer edge of the hub assembly using a winding process, with its inner surface interlocking with the wavy structure, forming a triple-layered connection of curing pre-tightening, mechanical meshing, and centrifugal self-locking. The centrifugal passive balancing unit includes an annular balancing groove on the end face of the hub assembly and freely rolling balancing balls within the groove, used to automatically compensate for rotor imbalance due to centrifugal force. The central radial electromagnetic bearing, upper radial support assembly, and lower radial support assembly form a three-point distributed radial support system along the axial direction.
[0010] As a further technical limitation, the carbon fiber rim adopts a fiber-wound integral curing structure, and the curing shrinkage generates an initial pre-tightening force at the interface; as the rotational speed increases, the radial expansion of the hub is greater than the expansion of the rim, and the positive pressure on the mating surface increases adaptively, thereby achieving centrifugal self-locking.
[0011] As a further technical limitation, the annular balance grooves are respectively set on the upper and lower end faces of the split hub assembly, and the balance balls are high-precision steel balls that can roll freely along the circumference of the annular balance grooves; the axial thrust bearing is set on the bottom base of the energy storage device housing, independently bearing the axial load under all working conditions, and realizing the mechanical decoupling of axial and radial support.
[0012] As a further technical limitation, when the rotor operates eccentrically, the balancing balls move to the opposite side of the eccentricity under the action of centrifugal force, automatically offsetting the unbalanced torque and realizing passive real-time dynamic balance adjustment.
[0013] As a further technical limitation, the lower radial support assembly includes the lower radial electromagnetic bearing and the lower radial bearing group, and the upper radial support assembly includes the upper radial electromagnetic bearing and the upper radial bearing assembly; the upper radial support assembly and the lower radial support assembly are arranged coaxially and nested to form a cooperative support structure of electromagnetic main support and mechanical auxiliary support.
[0014] As a further technical limitation, a centrifugal passive balance high-speed magnetic levitation flywheel energy storage device also includes a lower displacement sensor and an upper displacement sensor for real-time monitoring of the radial displacement of the shaft system to realize closed-loop control of the shaft system's operating attitude. The lower displacement sensor and the upper displacement sensor are respectively installed on the lower radial support assembly and the upper radial support assembly.
[0015] As a further technical limitation, the radial cross-section of the hub disc is a structure with equal strength gradient: the outer edge side cross-section is thinner, and the thickness increases uniformly along the radial direction towards the axis, which is used to make the radial stress distribution of the hub uniform and to maximize the radial deformation under strength constraints.
[0016] As a further technical limitation, the weight reduction structure is a circumferentially uniformly and symmetrically distributed weight reduction groove or weight reduction hole, which ensures that the circumferential stiffness of the hub is consistent. When rotating at high speed, the hub deforms uniformly along the circumference, forming a uniform radial extrusion force on the carbon fiber rim.
[0017] As a further technical limitation, the wave-shaped meshing structure is a circumferentially uniformly distributed arc-shaped or trapezoidal tooth structure that meshes with the corresponding grooves on the inner surface of the wound carbon fiber rim, providing mechanical redundancy for circumferential torque transmission.
[0018] As a further technical limitation, the inner ring of each wheel disc in the split wheel hub assembly is provided with an internal spline, and the corresponding position of the flywheel shaft is provided with an external spline. Circumferential positioning and torque transmission are achieved through spline engagement, and each wheel disc can be processed and assembled independently.
[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a ball-bearing passive balancing structure, eliminating the need for additional drive components and control systems. It relies on centrifugal force to achieve real-time automatic compensation for imbalances, effectively counteracting vibrations caused by rotor eccentricity, reducing the control load and adjustment difficulty of the magnetic levitation bearing, and significantly improving the stability and reliability of the flywheel during high-speed continuous operation. Through a topological design involving circumferentially symmetrical material reduction on the hub end face, the radial stiffness of the hub is actively optimized, ensuring that the radial expansion of the hub at high speeds exceeds the expansion of the carbon fiber rim, resulting in a situation where "the higher the speed, the stronger the clamping force." The adaptive centrifugal self-locking effect completely reverses the defect of traditional structures where preload decreases with speed. Combined with wave-shaped mechanical meshing, it forms a triple connection redundancy, ensuring reliable torque transmission and strong anti-slip capability, supporting the flywheel to break through to higher speed levels. At the same time, the use of equal strength gradually changing cross section design and circumferential symmetrical weight reduction structure ensures uniform radial stress and consistent circumferential deformation of the hub, maximizing deformation while avoiding local stress overload and uneven clamping force, balancing structural strength and self-locking efficiency. The triple connection redundancy formed by curing shrinkage preload, wave-shaped mechanical meshing, and speed-adaptive centrifugal self-locking makes the torque transmission path more reliable. Combined with the vibration suppression effect of the passive balancing unit, it effectively reduces the amplitude of alternating stress, extends the fatigue life of the rotor structure, and improves the overall operating safety and service life of the high-speed flywheel. Attached Figure Description
[0020] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.
[0021] Figure 1 This is a schematic diagram of the overall cross-sectional structure of a centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the external appearance of a centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the centrifugal passive balancing unit structure in an embodiment of the present invention. Figure 4 This is a schematic diagram of the split-type wheel hub assembly and end face structure in an embodiment of the present invention. Figure 5 This is a schematic diagram of the wavy carbon fiber rim in an embodiment of the present invention; Figure 6 This is a schematic diagram of the split wheel hub and carbon fiber rim assembly in an embodiment of the present invention; Among them, 1. Thrust bearing; 2. Lower displacement sensor; 3. Bottom shaft; 4. Flywheel shaft; 5. Middle radial electromagnetic bearing; 6. Motor stator; 7. Upper radial electromagnetic bearing; 8. Upper radial bearing assembly; 9. Upper displacement sensor; 10. Motor rotor shaft; 11. Energy storage device housing; 12. Energy storage flywheel hub; 13. Carbon fiber rim; 14. Axial thrust bearing; 15. Lower radial electromagnetic bearing; 16. Lower radial bearing assembly; 17. Ball bearing; 18. Annular balance groove. Detailed Implementation
[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0024] 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 scope of exemplary embodiments according to the invention. 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.
[0025] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.
[0026] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.
[0027] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.
[0028] Example This invention provides an embodiment of a centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device.
[0029] Existing high-speed flywheel rotor technology cannot simultaneously achieve multiple technical goals such as high-stability passive balancing, highly reliable rim self-locking connection, and easy machining and assembly, which severely restricts the performance improvement and engineering implementation of high-speed, high-energy-density flywheel energy storage equipment. Therefore, this embodiment introduces a flywheel rotor structure that possesses centrifugal self-locking effect and balances high-speed self-balancing with convenient assembly.
[0030] like Figure 1 and Figure 2 The centrifugal passive balance high-speed magnetic levitation flywheel energy storage device shown includes an energy storage device housing 11, a thrust bearing 1, a lower radial bearing assembly 16, a lower displacement sensor 2, a lower radial electromagnetic bearing 15, an axial thrust bearing 14, a bottom shaft 3, a flywheel shaft 4, an energy storage flywheel rotor assembly, a middle radial electromagnetic bearing 5, a motor stator 6, a motor rotor shaft 10, an upper radial electromagnetic bearing 7, an upper displacement sensor 9, and an upper radial bearing assembly 8.
[0031] In this embodiment, the axial thrust bearing 14, lower radial electromagnetic bearing 15, lower radial bearing assembly 16, lower displacement sensor 2, and thrust bearing 1 are sequentially assembled from bottom to top at the bottom of the flywheel energy storage device. Each component is coaxially positioned and precisely fitted with the bottom shaft 3, forming a rigid support and axial bidirectional limiting structure at the bottom of the shaft system, bearing all axial loads of the shaft system and the radial support of the foundation. The energy storage flywheel rotor assembly is fixed in the middle section of the flywheel shaft 4 and consists of three parts: a split hub assembly 12, a carbon fiber rim 13, and a centrifugal passive balancing unit.
[0032] like Figure 4 The split-type wheel hub assembly shown is composed of multiple wheel hub discs stacked along the axial direction. Each wheel hub disc has an inner spline on its inner ring, which meshes with the outer spline at the corresponding position of the flywheel shaft 4 to achieve circumferential positioning and torque transmission. The outer edge of the wheel hub assembly adopts a wave-shaped topological meshing structure to replace the traditional smooth cylindrical surface.
[0033] Hub and disc radial stiffness design: The end face of the disc is symmetrically designed with weight reduction grooves along the circumference. The radial centrifugal stiffness of the hub is actively reduced by topological subtraction, so that the radial expansion of the hub at the rated working speed is greater than the radial expansion of the carbon fiber rim 13, forming a centrifugal self-locking effect with greater clamping force on the mating surface as the speed increases. The weight reduction structure adopts a uniform and symmetrical arrangement on the end face to ensure consistent circumferential stiffness of the hub and uniform circumferential deformation of the hub during high-speed rotation, forming a uniform radial extrusion force on the carbon fiber rim and avoiding uneven local stress. The radial section of the wheel hub adopts a gradient design with equal strength: the outer edge section is thinner, and the thickness increases uniformly from the radial direction to the axis, so as to make the radial stress distribution of the wheel hub uniform and maximize the radial deformation under the premise of meeting the structural strength constraints.
[0034] The carbon fiber rim 13 is integrally cured and formed on the outer edge of the split wheel hub assembly 12 using a fiber winding process. During the winding process, the fibers are tightly arranged along the wavy topology of the outer edge of the hub. After curing, the inner surface of the rim is completely interlocked with the wavy structure of the outer edge of the hub, forming a triple composite connection structure of "curing shrinkage pre-tightening + wavy mechanical engagement + centrifugal self-locking". Figure 5 and Figure 6 As shown.
[0035] Under static and low-speed conditions, the interface preload generated by the curing and shrinkage of carbon fiber provides basic positive pressure and friction. As the speed increases, the hub generates greater radial expansion due to its lower radial stiffness. The positive pressure on the mating surface continues to increase with the speed, achieving adaptive clamping and self-locking. The wave-shaped meshing structure also provides mechanical meshing redundancy, ensuring reliable torque transmission and eliminating the risk of radial slippage and circumferential slippage of the wheel rim.
[0036] like Figure 3 As shown, the centrifugal passive balancing unit has annular balancing grooves 18 on the upper and lower surfaces of the split hub assembly 12, and several freely rolling balancing balls 17 are filled in the grooves. When the rotor is eccentric, the balls automatically move to the opposite side of the eccentricity under the action of centrifugal force, which compensates for the imbalance in real time and suppresses the bow-shaped rotation and vibration amplitude.
[0037] The bottom end of the flywheel shaft 4 and the top end of the bottom shaft 3 are connected by a cylindrical interference fit, and the top end of the flywheel shaft 4 and the bottom end of the motor rotor shaft 10 are connected by a cylindrical interference fit to eliminate the shaft section connection gap and ensure coaxiality and torsional transmission stiffness.
[0038] The central radial electromagnetic bearing 5 is coaxially mounted between the upper section of the flywheel shaft 4 and the energy storage device housing 11, serving as the central radial support point of the shaft system; the motor stator 6 is fixedly installed on the inner wall of the energy storage device housing 11, and cooperates with the motor rotor shaft 10 to realize electromechanical energy conversion; the upper radial electromagnetic bearing 7, the upper displacement sensor 9, and the upper radial bearing assembly 8 are coaxially mounted from bottom to top on the upper section of the motor rotor shaft 10, serving as the upper radial support point of the shaft system.
[0039] The lower radial electromagnetic bearing 15, the middle radial electromagnetic bearing 5, and the upper radial electromagnetic bearing 7 form a three-point distributed radial support along the shaft system axis, which, together with the axial thrust bearing 14, provides full-dimensional axial positioning and constructs a stable magnetic levitation support system, providing basic support for the high-speed operation of the rotor.
[0040] The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device in this embodiment adopts an integrated design scheme of stiffness-optimized self-locking rotor structure, wound and solidified integrated wheel rim, centrifugal passive balancing unit and three-section interference shaft system. The whole assembly is installed inside the sealed energy storage device box, which has vacuum / airtight environment adaptability and can meet the operation requirements of high-speed magnetic levitation flywheel energy storage system.
[0041] As one or more implementation methods, this embodiment performs modular pre-construction of the bottom support structure; specifically: The axial thrust bearing 14 is coaxially press-fitted onto the bottom base of the energy storage device housing 11. As the core component of the axial bearing system, it independently bears the axial load under all working conditions of start-up, steady-state operation, and emergency braking, thus achieving mechanical decoupling between axial and radial supports.
[0042] The lower radial electromagnetic bearing 15, the lower radial bearing assembly 16, and the lower displacement sensor 2 are coaxially assembled in sequence, and each component meets the high-precision coaxiality requirements. The lower radial bearing assembly 16 and the lower radial electromagnetic bearing 15 adopt a nested cooperative support structure, which takes into account both the active electromagnetic support under normal working conditions and the auxiliary mechanical support under abnormal working conditions.
[0043] The bottom shaft 3 is precisely connected to the bottom support component to complete the pre-installation of the bottom support module, realizing the functions of axial bidirectional positioning and foundation radial support.
[0044] As one or more implementation methods, this embodiment involves modular pre-assembly of the flywheel rotor assembly; specifically: The single hub disc adopts a uniform strength gradient cross section design: the cross section thickness is thinnest at the outer edge, and the thickness increases uniformly from the radial direction to the axis. The cross section gradient curve is optimized through finite element simulation to make the radial stress distribution uniform and maximize the radial deformation within the strength allowable range.
[0045] The wheel's two end faces are symmetrically machined with uniformly distributed weight-reducing grooves along the circumference, actively reducing the radial centrifugal stiffness of the hub through topological subtraction. The weight-reducing structure is strictly arranged circumferentially to ensure consistent circumferential stiffness of the hub, uniform deformation during high-speed rotation, and uniform circumferential distribution of extrusion pressure. The outer edge of the wheel is prefabricated with a circumferentially uniformly distributed wave-shaped meshing tooth structure.
[0046] Multiple independently machined wheel hubs and discs are sequentially coupled with the external splines of the flywheel shaft 4 via internal splines, stacked and positioned axially and locked in the axial direction. The spline engagement enables precise circumferential positioning and reliable torque transmission.
[0047] Carbon fiber is laid on the outer edge of the assembled split wheel hub assembly 12 using wet or dry winding processes. During the winding process, the fiber tension and arrangement angle are controlled so that the fiber bundles are tightly embedded in the wavy grooves of the outer edge of the wheel hub, ensuring that the inner surface of the rim is completely fitted with the topology of the wheel hub.
[0048] After winding, a curing process is performed. The curing temperature and heating rate are strictly matched to the characteristics of the carbon fiber matrix material and controlled below the glass transition temperature of the carbon fiber to ensure that the material performance is not affected. During the curing process, the carbon fiber undergoes volume shrinkage, forming a stable initial preload at the interface between the hub and the rim. At the same time, the wavy meshing structure forms a mechanical interlocking interface.
[0049] Under rated speed conditions, the hub expands radially under centrifugal force. Since its radial stiffness is lower than the radial expansion stiffness of the rim after material reduction design, the hub expansion is greater than the rim expansion. The normal pressure on the mating surface increases with the speed, forming a centrifugal self-locking effect. The higher the speed, the tighter the connection.
[0050] A set number of high-precision balance balls 17 are installed in the annular balance grooves 18 on the upper and lower ends of the split hub assembly 12. A lubricating medium suitable for a vacuum environment is added to the grooves, and then the groove openings are sealed to ensure that the balls can roll freely in the annular grooves without jamming.
[0051] The bottom end of the flywheel shaft 4 and the top end of the bottom shaft 3 are press-fitted with a cylindrical surface interference fit. The pressing force is controlled within the rated range to ensure a firm connection without loosening and that the coaxiality of the shaft sections meets the design requirements.
[0052] The central radial electromagnetic bearing 5 is coaxially assembled between the upper section of the flywheel shaft 4 and the energy storage device housing 11, serving as the second radial support point of the shaft system and providing radial support constraint for the flywheel rotor section.
[0053] As one or more implementation methods, this embodiment involves modular pre-assembly of the upper motor shaft section; specifically: The motor stator 6 is fastened to the inner wall of the energy storage device housing 11 by bolts, and the coaxiality accuracy of the stator and rotor is ensured by locating pins for auxiliary calibration.
[0054] The bottom end of the motor rotor shaft 10 and the top end of the flywheel shaft 4 are connected by a cylindrical interference fit, and the fitting parameters are consistent with those of the lower shaft connection, so as to achieve efficient power transmission and high-precision coaxial operation.
[0055] The radial electromagnetic bearing 7, the upper displacement sensor 9, and the upper radial bearing assembly 8 are sequentially and coaxially assembled to serve as the third radial support point of the shaft system, thereby strengthening the support stiffness of the motor rotor shaft section and suppressing vibration and radial offset.
[0056] As one or more implementation methods, this embodiment performs system integration and debugging; specifically: The pre-assembled shaft system and rotor are hoisted into the energy storage device housing 11, and the electrical wiring, vacuum sealing and routine performance testing of each component are completed.
[0057] The lower displacement sensor 2 and the upper displacement sensor 9 monitor the radial displacement of the bottom and upper shaft systems in real time, forming a closed-loop monitoring system for the entire displacement stroke. This, together with the magnetic levitation bearing control system, ensures that the shaft system's operating posture is precise and controllable.
[0058] The test was conducted sequentially with no-load commissioning, gradient speed-up testing, and high-speed full-load testing to verify key parameters such as rotor vibration amplitude, imbalance compensation effect, flange connection reliability, and bearing temperature. Test results show that the passive balancing unit effectively suppresses high-speed vibration; at the rated maximum speed, the clamping force between the hub and flange mating surfaces is significantly increased compared to the static state, with no slippage or loosening; circumferential deformation is uniform, stress distribution is reasonable, and the overall rotor operational stability and safety margin are significantly better than traditional solutions.
[0059] This embodiment adopts a ball-type passive balancing structure, which does not require additional drive components and control systems. It relies on the principle of centrifugal force to achieve real-time automatic compensation of imbalance, effectively counteracting the vibration caused by rotor eccentricity, reducing the control load and adjustment difficulty of the magnetic levitation bearing, and greatly improving the stability and reliability of the flywheel's high-speed continuous operation.
[0060] This embodiment breaks away from the traditional connection approach that relies solely on initial interference fit. Through a topological design involving circumferentially symmetrical material reduction on the hub end face, it actively optimizes the hub's radial stiffness. This ensures that the radial expansion of the hub at high speeds exceeds the expansion of the carbon fiber rim, creating an adaptive centrifugal self-locking effect where "the higher the speed, the stronger the clamping force," completely reversing the defect of traditional structures where preload decreases with speed. Combined with a wave-shaped mechanical meshing system forming triple connection redundancy, torque transmission is reliable, and anti-slip capability is strong, supporting the flywheel's breakthrough to higher speed levels. Simultaneously, the use of a uniform strength gradually changing cross-section design and a circumferentially symmetrical weight reduction structure ensures uniform radial stress and consistent circumferential deformation of the hub. This maximizes deformation while avoiding localized stress overload and uneven clamping force, balancing structural strength and self-locking effectiveness.
[0061] In this embodiment, the carbon fiber rim is formed by in-situ winding and curing process, eliminating the need for separate rim processing and subsequent assembly. The inner surface of the rim precisely fits into the wave-shaped structure of the hub, resulting in a higher degree of interface fit. The initial preload is naturally formed by utilizing the curing shrinkage characteristics of carbon fiber, avoiding thermal stress damage and assembly coaxiality errors caused by hot assembly. This results in better process consistency and significantly improved interface connection reliability.
[0062] This embodiment breaks down the traditional integral large-size wheel hub into multiple independent wheel disc units, which are assembled with the shaft through a spline structure. This significantly reduces the processing difficulty and geometric tolerance requirements of individual components, and improves material utilization. During assembly, the wheels can be stacked and calibrated in stages, and the corresponding wheel discs can be replaced individually if there is local damage later. This greatly reduces maintenance costs and enhances engineering adaptability.
[0063] In this embodiment, the solidification shrinkage pre-tightening, wave-shaped mechanical meshing, and speed-adaptive centrifugal self-locking form a triple connection redundancy, making the torque transmission path more reliable. Combined with the vibration suppression effect of the passive balancing unit, it effectively reduces the amplitude of alternating stress, extends the fatigue life of the rotor structure, and improves the overall operational safety and service life of the high-speed flywheel.
[0064] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
[0065] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.
Claims
1. A centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device, characterized in that, The device includes an energy storage housing, an axial thrust bearing and a lower radial support assembly located at the bottom of the housing, a bottom shaft, a flywheel shaft, an energy storage flywheel rotor assembly fixed on the flywheel shaft, a central radial electromagnetic bearing, a motor stator, a motor rotor shaft, and an upper radial support assembly. The bottom end of the flywheel shaft is connected to the top end of the bottom shaft, and the top end of the flywheel shaft is connected to the bottom end of the motor rotor shaft via a cylindrical interference fit. The energy storage flywheel rotor assembly includes a split-type hub assembly, a carbon fiber rim, and a centrifugal passive balancing unit. The split-type hub assembly is composed of multiple hub discs stacked axially, each hub disc connected to the flywheel shaft via a spline, and the outer edge of the hub assembly is corrugated. The hub features a wave-shaped meshing structure. A symmetrical weight-reducing structure is arranged circumferentially on the end face of the hub disc, ensuring that the radial expansion of the hub at rated speed is greater than the radial expansion of the carbon fiber rim, thus forming centrifugal self-locking. The carbon fiber rim is cured and formed on the outer edge of the hub assembly using a winding process, with its inner surface interlocking with the wave-shaped structure, forming a triple-layered connection of curing pre-tightening, mechanical meshing, and centrifugal self-locking. The centrifugal passive balancing unit includes an annular balancing groove on the end face of the hub assembly and freely rolling balancing balls within the groove, used to automatically compensate for rotor imbalance due to centrifugal force. The central radial electromagnetic bearing, upper radial support assembly, and lower radial support assembly form a three-point distributed radial support system along the axial direction.
2. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The carbon fiber rim adopts a fiber-wound integral curing structure, and the curing shrinkage generates an initial pre-tightening force at the interface. As the rotational speed increases, the radial expansion of the hub exceeds the expansion of the rim, and the normal pressure on the mating surface increases adaptively, achieving centrifugal self-locking.
3. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The annular balance grooves are respectively set on the upper and lower end faces of the split hub assembly. The balance balls are high-precision steel balls that can roll freely along the circumference of the annular balance grooves. The axial thrust bearing is set on the bottom base of the energy storage device housing and independently bears the axial load under all working conditions, realizing the mechanical decoupling of axial and radial support.
4. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, When the rotor operates eccentrically, the balancing balls move to the opposite side of the eccentricity under the action of centrifugal force, automatically counteracting the unbalanced torque and realizing passive real-time dynamic balance adjustment.
5. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The lower radial support assembly includes the lower radial electromagnetic bearing and the lower radial bearing group, and the upper radial support assembly includes the upper radial electromagnetic bearing and the upper radial bearing assembly; the upper radial support assembly and the lower radial support assembly are arranged coaxially and nested to form a cooperative support structure of electromagnetic main support and mechanical auxiliary support.
6. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, It also includes a lower displacement sensor and an upper displacement sensor for real-time monitoring of the radial displacement of the shaft system to achieve closed-loop control of the shaft system's operating attitude. The lower displacement sensor and the upper displacement sensor are respectively installed on the lower radial support assembly and the upper radial support assembly.
7. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The radial cross-section of the hub disc is a structure with equal strength gradient: the outer edge side section is thinner, and the thickness increases uniformly from the radial direction to the axis, which is used to make the radial stress distribution of the hub uniform and to maximize the radial deformation under strength constraints.
8. The centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The weight-reducing structure consists of circumferentially uniformly and symmetrically distributed weight-reducing grooves or holes, ensuring consistent circumferential stiffness of the hub. During high-speed rotation, the hub deforms uniformly along the circumference, creating a uniform radial compressive force on the carbon fiber rim.
9. A centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The wave-shaped meshing structure consists of circumferentially evenly distributed arc-shaped or trapezoidal teeth that mesh with the corresponding grooves on the inner surface of the wound carbon fiber rim, providing mechanical redundancy for circumferential torque transmission.
10. A centrifugal passively balanced high-speed magnetic levitation flywheel energy storage device as described in claim 1, characterized in that, The split-type wheel hub assembly has internal splines on the inner ring of each wheel disc and external splines on the corresponding position of the flywheel shaft. Circumferential positioning and torque transmission are achieved through spline engagement, and each wheel disc can be machined and assembled independently.