Laminated pull rod fastening energy storage flywheel rotor structure, assembling method and application

Abstract

The invention discloses a laminated pull rod fastening energy storage flywheel rotor structure, an assembling method and application. The flywheel rotor structure comprises an upper long shaft, an upper pressing disc, a circular plate lamination, a lower pressing disc, a lower long shaft, a ladder arc special-shaped pull rod and other assemblies. The upper and lower pressure plates are gradually thinned from inside to outside; dovetail grooves are formed in the outer edges of the upper pressing disc, the lower pressing disc and the middle laminated circular plate, the ladder arc special-shaped pull rods penetrate through channels of the dovetail grooves from bottom to top and are attached to the two side faces of the dovetail grooves, and the upper pressing disc, the lower pressing disc and the laminated circular plates are locked through nuts. The steel material of the combined structure is easier to manufacture and lower in cost, and the circular plate can be regularly replaced to sample and inspect the mechanical property in the using process, so that the overall fatigue life of the combined flywheel is judged; the kinetic energy of the single plate after fatigue damage is far lower than that of the whole flywheel, and the damage degree to equipment is greatly reduced. The overall rigidity, the anti-fatigue performance and the operation stability of the laminated flywheel rotor are remarkably improved, meanwhile, regular disassembly, detection and maintenance are facilitated, and the laminated flywheel rotor is suitable for high-power energy storage.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage devices, and relates to the structural optimization and assembly of high-speed energy storage flywheels. Specifically, it relates to a laminated tie rod fastening energy storage flywheel rotor structure, an assembly method and an application, which can achieve uniform stress distribution, improved overall stiffness and optimized fatigue life under high-speed operation of the laminated flywheel rotor. Background Art

[0002] Energy storage technologies such as compressed air energy storage and flywheel energy storage have developed rapidly in recent years and shown great application potential in fields such as power grid peak shaving, energy recovery, and uninterruptible power supplies. Compared with traditional chemical energy storage methods, flywheel energy storage has many advantages such as fast charge and discharge rates, high energy conversion efficiency, long cycle life, and environmental friendliness, especially in short-term high-power application scenarios. With the continuous increase in the proportion of new energy connected to the grid, the volatility and instability of the power grid have become increasingly prominent. As a fast-response and high-efficiency energy storage means, flywheel energy storage is of great significance for maintaining power grid stability.

[0003] The flywheel body is the main energy storage component in the flywheel energy storage system, and its material properties and structural shape directly determine the energy storage capacity, operation reliability and economy of the flywheel. Traditional flywheel bodies are usually integrally forged from high-strength metal materials (such as alloy steel, titanium alloy, etc.). Its advantages are compact structure, mature manufacturing process, and relatively high maximum energy density of a single flywheel. However, there are significant material stress concentration problems in the integrally forged flywheel under high-speed operation conditions. Especially during the heat treatment process, due to the hardenability problem of metal materials, such as uneven heat treatment, it will affect the mechanical properties of the overall material, especially the internal part, bringing certain adverse effects to the reliability of the rotor. At the same time, the cost of the integrally forged flywheel is relatively high, and it is not easy to conduct reliability tests in the later stage. Once cracks or fatigue damage occur, it is often difficult to repair or replace, posing a relatively large safety risk.

[0004] In contrast, the layered flywheel is constructed by stacking multiple layers of discs or segmentally combining them, and forms an integral structure through bonding or mechanical connection. The layered flywheel reduces the manufacturing cost to a certain extent and is convenient for local maintenance and detection. However, there are still some deficiencies in the existing layered flywheels. For example, the common fastening methods for layered flywheels currently include bolt connection, key connection, etc. These methods may cause structural loosening or stress concentration, affecting long-term stability. Since the layered flywheel usually adopts a multi-point fastening method, the force between different discs is uneven, affecting the overall stiffness and fatigue life. In addition, the layered structure will generate small relative slips during high-speed rotation, causing additional energy losses and reducing the system efficiency.

[0005] For example, Chinese invention patent application CN103867639A discloses a large energy storage flywheel rotor and a method for making the same, wherein the rim is a multi-layer carbon fiber reinforced composite annular structure, which is fitted onto a metal hub by interference fit and glued between the mating surfaces. This solution improves stress distribution by means of interference fit of split rings, but the manufacturing and assembly processes of the multi-layer rings are complicated, and the long-term reliability of the bonding interface remains to be verified. For another example, Chinese invention patent application CN105518339A discloses a flywheel for energy storage and a method for making the same, which constructs a flywheel rotor bracket by using a laminate of composite sheets and a woven fabric side layer, and resists the delamination of the laminate by using a woven fabric side layer. This solution focuses on the structural design of the rotor bracket, but there is still room for improvement in how to effectively connect multiple composite sheets into a whole and how to ensure the stability of the rotor at high speeds.

[0006] In summary, large-sized integral flywheels made of high-strength metal materials have problems with material hardenability, high manufacturing costs, and difficult reliability testing, while existing layered flywheels still have some shortcomings. Therefore, how to optimize the structural design of the flywheel to improve structural stability, fatigue life, detection feasibility, and operational safety while ensuring high speed and high energy storage capacity is a technical problem that needs to be solved urgently in the current field of flywheel energy storage technology. Summary of the invention

[0007] 1. Purpose of the invention In view of the defects and deficiencies in the above-mentioned prior art, the present invention aims to propose a laminated tie rod fastening energy storage flywheel rotor structure, assembly method and application, which adopts a structure of a combination of a thin circular plate laminate and a pressure plate, and ensures the overall stiffness and uniformity of stress distribution of the flywheel rotor under high-speed operation through the matching design of the ladder arc special-shaped tie rod and the dovetail groove. At the same time, the design of the pressure plate gradually becoming thinner from the inside to the outside effectively reduces the overall stress level of the structure. In addition, the present invention facilitates the regular disassembly, replacement and inspection of the flywheel during use through a modular design, thereby improving the fatigue life assessment capability and safety of the flywheel. Through the above-mentioned technical scheme, the present invention significantly improves the safety, manufacturing feasibility and maintenance convenience of the structure while ensuring the high energy density of the flywheel energy storage system, thereby meeting the technical requirements of high-performance flywheel energy storage systems in high-speed, long-life and high-stability application scenarios.

[0008] (II) Technical solution In order to achieve the purpose of the invention and solve the technical problems, the present invention adopts the following technical solutions: The first invention object of the present invention is to provide a laminated tie rod fastened energy storage flywheel rotor structure, which is used for kinetic energy storage and release of a flywheel energy storage device, optimizes the structural stress of the flywheel rotor, improves fatigue resistance and enhances maintenance convenience, including: The upper long shaft is used to provide the upper support and power transmission of the flywheel rotor, and its lower end is coaxially and fixedly connected to the top surface of the upper pressure plate; The upper pressure plate has a flat bottom surface, the thickness of the top surface gradually thins from the inside to the outside along the radial direction, and there is a raised step at the center of the top surface, and dovetail grooves are evenly arranged on the circumferential outer edge thereof; The circular plate stack is composed of multiple coaxially stacked circular plates, and dovetail grooves that match the positions and shapes of the dovetail grooves on the upper pressure plate are evenly arranged on the outer edges of the circular plates; The lower pressure plate has a flat top surface, the thickness of the bottom surface gradually thins from the inside to the outside along the radial direction, and there is a raised step at the center of the bottom surface, and dovetail grooves that match the positions and shapes of the dovetail grooves on the circular plates are evenly arranged on the circumferential outer edge thereof; The lower long shaft is used to provide the lower support and power transmission of the flywheel rotor, and its upper end is coaxially and fixedly connected to the bottom surface of the lower pressure plate; and The trapezoidal arc-shaped special-shaped tie rods are circumferentially distributed and the number corresponds to the dovetail grooves. Each tie rod passes through the dovetail groove channels of the lower pressure plate, the circular plate stack and the upper pressure plate from bottom to top. The cross-sectional shape thereof is closely attached to the two side surfaces of the dovetail groove, and its end fastens the upper and lower pressure plates and the circular plate stack into an integral structure through a locking assembly.

[0009] The second object of the present invention is to provide an assembly method for the laminated tie rod fastening energy storage flywheel rotor structure as described above, which at least includes the following steps: SS1. Component preparation: Detect and confirm that the dimensional accuracy and surface quality of the upper long shaft, the upper pressure plate, each circular plate, the lower pressure plate, the lower long shaft, and multiple trapezoidal arc-shaped special-shaped tie rods and locking assemblies meet the design requirements; SS2. Positioning and installation of the pressure plate and the long shaft: Coaxially and fixedly connect the upper long shaft and the upper pressure plate, and the lower long shaft and the lower pressure plate respectively, and ensure that the coaxiality error is less than the preset threshold; SS3. Pre-alignment assembly of the circular plate stack: Stack multiple circular plates coaxially between the upper pressure plate and the lower pressure plate, and ensure that the dovetail grooves on the outer edges of the circular plates form a continuous and through circumferential channel with the dovetail grooves on the upper pressure plate and the lower pressure plate through a positioning tooling, and the cumulative circumferential deviation does not exceed the preset threshold; SS4. Insertion and fitting of the trapezoidal arc-shaped special-shaped tie rods: Insert the trapezoidal arc-shaped special-shaped tie rods into the dovetail grooves of the lower pressure plate from bottom to top along the circumference, sequentially pass through the dovetail grooves of the circular plate stack and the dovetail grooves of the upper pressure plate, and ensure that the cross-section of the tie rod is closely attached to the two side surfaces of each dovetail groove, and the fitting gap is less than the preset threshold; SS5. Axial pre-tightening force loading and locking: Install a locking assembly at the upper end of the trapezoidal arc-shaped special-shaped pull rod, apply axial pre-tightening force through torque control, so that the contact surface pressure of the upper pressure plate, circular plate stack and lower pressure plate is evenly distributed at 20 - 50 MPa, and use a locknut with an anti-loosening structure to prevent loosening; SS6. Quality inspection: Conduct dynamic balance testing, dimensional inspection and pre-tightening force verification on the assembled flywheel rotor structure to ensure that its dynamic balance accuracy and structural stiffness meet the design requirements.

[0010] The third invention object of the present invention is to provide a flywheel energy storage system, including the above-mentioned laminated pull rod fastening energy storage flywheel rotor structure of the present invention.

[0011] (III) Technical effects Compared with the prior art, the laminated pull rod fastening energy storage flywheel rotor structure, assembly method and application of the present invention have the following beneficial and remarkable technical effects: (1) The present invention adopts a combined structure of thin circular plate stack + pressure plate + shaft. Compared with the integrally forged flywheel, its steel material is easier to manufacture, reducing the overall processing difficulty and production cost. At the same time, each component is easy to detect the crack state of the material. By regularly disassembling and replacing the circular plates and conducting mechanical property inspection on the replaced circular plates, the overall fatigue life of the combined flywheel can be effectively evaluated, solving the problems in aspects such as crack detection, mechanical property detection and characterization, and fatigue evaluation of the overall thick rotor and long shaft structure, improving the reliability and maintenance convenience of the flywheel rotor.

[0012] (2) The present invention adopts a dovetail groove design with an opening at the circular edge, and its stress level is lower than that of the closed groove inside the disc, effectively reducing the stress concentration of the flywheel rotor during high-speed operation and improving the anti-fatigue performance of the structure. At the same time, the pressure plate adopts an approximately equal stress variable thickness and a convex step structure at the center, avoiding the stress increase effect of the inner hole and threaded hole of the protruding step, further reducing the overall stress level of the structure, thereby improving the strength and anti-fatigue performance of the structure.

[0013] (3) The present invention adopts trapezoidal arc-shaped special-shaped pull rods distributed in multiple circumferential directions, ensuring the overall stiffness of the combined rotor and improving the stability of the structure. The trapezoidal arc-shaped special-shaped pull rods adopt lightweight high-strength titanium alloy and titanium alloy nuts, greatly reducing the external load on the opening groove and reducing the weight of the structure. In addition, the kinetic energy after the single plate fatigue failure is much lower than that of the overall flywheel, which can greatly reduce the harm degree to the equipment, thereby improving the overall safety and reliability.

[0014] (4) The design of the laminated structure adopted by the present invention enables the flywheel rotor to have good modularity and scalability. The number of circular plates can be increased or decreased according to actual needs to adjust the energy storage capacity of the flywheel rotor, so as to meet the application scenarios with different power and energy requirements. Brief Description of the Drawings

[0015] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. Hereinafter, the embodiments of the present invention will be described in detail in conjunction with the accompanying drawings, wherein: Figure 1 is a schematic diagram of the laminated tie rod fastening energy storage flywheel rotor structure of the present invention; Figure 2 is a top view of the upper pressure plate or a bottom view of the lower pressure plate of the present invention; Figure 3 is a top view of the laminated circular plate of the present invention; Figure 4 is a partial enlarged view of the assembly of the trapezoidal arc special-shaped tie rod and the dovetail groove of the present invention; Figure 5 is a flowchart of the assembly of the laminated tie rod fastening energy storage flywheel rotor structure of the present invention.

[0016] Description of the Reference Numerals: Flywheel rotor 100, upper long shaft 10, upper pressure plate 20, upper pressure plate dovetail groove 21, circular plate laminate 30, laminated circular plate 31, dovetail groove 32, lower pressure plate 40, lower pressure plate dovetail groove 41, lower long shaft 50, trapezoidal arc special-shaped tie rod 60, bolt 70. Detailed Description of the Embodiments

[0017] The present invention aims to provide a laminated tie rod fastening energy storage flywheel rotor structure, an assembly method and an application. To make the purpose, technical solutions and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, not all of the embodiments, and the described embodiments are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0018] Embodiment 1: Energy Storage Flywheel Rotor Structure As Figures 1 to 4As shown in the figure, the laminated tie rod fastening energy storage flywheel rotor 100 structure provided by the present invention includes components such as an upper long shaft 10, an upper pressure plate 20, a circular plate laminate 30, a lower pressure plate 40, a lower long shaft 50, and a ladder arc-shaped special-shaped tie rod 60. Among them, the upper long shaft 10 is used to provide the upper support and power transmission of the flywheel rotor, and its lower end is coaxially and fixedly connected to the top surface of the upper pressure plate; the bottom surface of the upper pressure plate 20 is flat, the thickness of the top surface gradually thins from the inside to the outside along the radial direction, and a raised step is provided at the center of the top surface, and dovetail grooves 21 are evenly opened on the circumferential outer edge thereof; the circular plate laminate 30 is composed of multiple coaxially stacked circular plates 31, and dovetail grooves 32 that match the position and shape of the dovetail grooves 21 on the upper pressure plate are evenly opened on the outer edges of the circular plates; the top surface of the lower pressure plate 40 is flat, the thickness of the bottom surface gradually thins from the inside to the outside along the radial direction, and a raised step is provided at the center of the bottom surface, and dovetail grooves 41 that match the position and shape of the dovetail grooves 32 on the circular plate are evenly opened on the circumferential outer edge thereof; the lower long shaft 50 is used to provide the lower support and power transmission of the flywheel rotor, and its upper end is coaxially and fixedly connected to the bottom surface of the lower pressure plate; and the ladder arc-shaped special-shaped tie rods 60 are circumferentially distributed and the number corresponds to the dovetail grooves. Each tie rod passes upward through the dovetail groove channels of the lower pressure plate, the circular plate laminate, and the upper pressure plate. The cross-sectional shape thereof is closely attached to the two side surfaces of the dovetail groove, and its end fastens the upper and lower pressure plates and the circular plate laminate into an integral structure through a locking component.

[0019] Specifically, as Figure 1 shown, the shapes of the upper and lower pressure plates 20 and 40 of the present invention are variable-thickness structures with approximately equal stress design. The thicknesses of the top surface of the upper pressure plate 20 and the bottom surface of the lower pressure plate 40 gradually thin from the inside to the outside. The thickness change curve is calculated and determined according to the working speed and energy storage capacity requirements of the flywheel rotor, so as to effectively disperse the stress concentration phenomenon generated during the high-speed rotation of the flywheel rotor, avoid the adverse effects of stress concentration on the structural strength and fatigue life, and improve the overall fatigue resistance and service life of the flywheel rotor.

[0020] Preferably, flange parts are provided at the ends of the upper long shaft 10 and the lower long shaft 50. A raised part is provided at the center of the flange part, and several connection holes are provided circumferentially on the flange part; center positioning holes are provided on the raised steps at the center parts of the upper pressure plate 20 and the lower pressure plate 40. Threaded holes corresponding to the connection holes are opened on the outer circle of the center positioning holes. The axial depths of the threaded holes and the inner holes of the raised steps do not exceed the depth of the outer circle of the protruding part, so as to avoid the opening stress increase effect and reduce the overall stress level of the structure. The raised parts of the upper long shaft 10 and the lower long shaft 50 and the center positioning holes of the upper pressure plate 20 and the lower pressure plate 40 are in interference fit, and coaxial positioning and fixed connection are realized through bolts 70 based on the corresponding connection holes and threaded holes, ensuring the stability and concentricity of the flywheel rotor during high-speed rotation, and avoiding vibration and stress concentration caused by eccentricity.

[0021] Preferably, in the circular plate stack 30, the thickness of the stacked circular plates 31 is 10 - 100 mm, the diameter is 500 - 2000 mm, and the number is 3 - 30. The materials of the circular plates 31 can be the same or different. The contact surface roughness Ra ≤ 1.6 μm is ensured by precision grinding between the circular plates 31. By configuring the number, thickness, diameter, and material of the circular plates, the energy storage capacity and moment of inertia of the flywheel rotor can be flexibly adjusted to meet the energy storage requirements of different power levels. At the same time, the moment of inertia distribution is optimized to improve the energy storage efficiency and structural reliability. More specifically, for example, the diameter of the stacked circular plates 31 can be set to 1000 mm, the thickness to 35 mm, the number to 8, the total thickness to 350 mm, the connecting flange diameter to 300 mm, and the shaft diameter to 160 mm.

[0022] In addition, the thickness of each circular plate 31 in the circular plate stack 30 can be set to gradually increase from both ends to the middle along the axial direction. The circular plate located in the middle of the axis has the maximum thickness, and the circular plates at both ends have the minimum thickness. The change in the thickness of the circular plates is designed according to a preset gradient increasing rule, so that the circular plate stack 30 is integrally formed into a gradient variable thickness arrangement structure to optimize the overall stress distribution of the flywheel rotor, make the stress more evenly distributed on each circular plate, thereby improving the overall stiffness, fatigue resistance, and service life of the laminated flywheel rotor, and reducing the deformation generated during high-speed rotation.

[0023] Dovetail grooves 21, 41, and 32 are respectively provided at the outer edges of the upper pressing plate 20, the lower pressing plate 40, and each intermediate stacked circular plate 31 of the present invention. The number of dovetail grooves is adjusted between 8 and 32 according to actual application requirements, and the dovetail grooves are evenly distributed along the circumferential direction, and the openings face the radial outside of the circular plate. The cross-sectional shape of the dovetail groove is generally trapezoidal, with a side wall inclination angle of 45° - 60°, a bottom fillet radius R ≥ 2 mm, and its depth and width are optimized according to the size and working speed of the flywheel to ensure that it can withstand sufficient radial and tangential stresses under high-speed rotation conditions while maintaining the overall stiffness and fatigue resistance of the structure.

[0024] The trapezoidal arc-shaped special-shaped pull rod 60 of the present invention passes through the dovetail groove channel from bottom to top and fits against the two side surfaces of the dovetail groove. Nuts are used to lock the upper and lower pressure plates and multiple laminated circular plates. The upper shaft is bolted to the upper pressure plate, and the lower shaft is bolted to the lower pressure plate. The interference fit between the protruding stepped inner hole and the shaft is used to achieve coaxial positioning. Preferably, the trapezoidal arc-shaped special-shaped pull rod 60 and the locking nut at its end are made of a lightweight and high-strength titanium alloy material. The cross-sectional shape of the pull rod is trapezoidal arc-shaped and is designed to fit tightly against the two side surfaces of the dovetail groove, reducing the mass of the pull rod while reducing the external load on the dovetail groove. And preferably, the end face of the locking nut is provided with an anti-loosening serrated structure, and the tight fit between the upper pressure plate 20, the circular plate laminate 30 and the lower pressure plate 40 is ensured through pre-tightening force control, preventing relative slip and energy loss of the flywheel rotor during high-speed rotation. Moreover, the pre-tightening forces of the pull rods are kept consistent, and a mechanism for regular detection and adjustment of the pre-tightening force is set up to ensure that the flywheel rotor maintains stable structural stiffness and dynamic balance performance during long-term use, preventing loosening and vibration problems caused by insufficient or uneven pre-tightening force.

[0025] In summary, Embodiment 1 of the present invention provides a laminated pull rod fastening energy storage flywheel rotor structure. By optimizing the design of the circular plate laminate, the dovetail groove connection method, and the trapezoidal arc-shaped special-shaped pull rod fastening scheme, the structural stiffness, fatigue resistance, and dynamic balance stability of the flywheel rotor are effectively improved. At the same time, the detachable components, fatigue life monitoring, and convenient maintenance are realized, ensuring the long-term safe and reliable operation of the flywheel energy storage system under high rotational speed and high energy density conditions.

[0026] Embodiment 2: Assembly method Based on Embodiment 1 above, Embodiment 2 aims to further describe in detail the assembly method of the above-mentioned laminated pull rod fastening energy storage flywheel rotor structure. The assembly method mainly includes the following steps: SS1. Component preparation: Detect and confirm that the dimensional accuracy and surface quality of the upper long shaft 10, the upper pressure plate 20, each circular plate 31, the lower pressure plate 40, the lower long shaft 50, and multiple trapezoidal arc-shaped special-shaped pull rods 60 and locking components meet the design requirements; SS2. Positioning and installation of the pressure plate and the long shaft: Coaxially and fixedly connect the upper long shaft 10 to the upper pressure plate 20 and the lower long shaft 50 to the lower pressure plate 40 respectively, ensuring that the coaxiality error is less than a preset threshold (for example, 0.05 mm); SS3. Pre-alignment assembly of the circular plate laminate: Stack multiple circular plates 31 coaxially between the upper pressure plate 20 and the lower pressure plate 40. Through a positioning tooling, ensure that the dovetail grooves 32 on the outer edges of the circular plates form a continuous and through circumferential channel with the dovetail grooves 21 and 41 of the upper pressure plate 20 and the lower pressure plate 40, and the cumulative circumferential deviation does not exceed a preset threshold (for example, ±0.1°); SS4. Insertion and fitting of the trapezoidal arc-shaped special-shaped tie rod: Insert the trapezoidal arc-shaped special-shaped tie rod 60 upward from the dovetail groove 41 of the lower pressure plate 40 along the circumferential direction, successively pass through the dovetail groove 32 of the circular plate stack 30 and the dovetail groove 21 of the upper pressure plate 20, and ensure that the cross-section of the tie rod is in close contact with both side surfaces of each dovetail groove, and the fitting gap is less than a preset threshold value (for example, ≤0.05 mm); SS5. Axial pre-tightening force loading and locking: Install a locking assembly at the upper end of the trapezoidal arc-shaped special-shaped tie rod 60, apply an axial pre-tightening force by torque control, so that the contact surface pressure of the upper pressure plate 20, the circular plate stack 30 and the lower pressure plate 40 is evenly distributed at 20 - 50 MPa, and use a locking structure to lock the nut to prevent loosening; SS6. Quality inspection: Conduct dynamic balance testing, dimensional inspection and pre-tightening force verification on the assembled flywheel rotor structure to ensure that it meets the dynamic balance accuracy and structural stiffness required by the design.

[0027] Through the above assembly method, the efficient and precise assembly of the laminated tie rod fastened energy storage flywheel rotor structure is realized, ensuring the stability and reliability of the flywheel rotor under high-speed operation, and at the same time improving the assembly efficiency and maintenance convenience.

[0028] Through the above embodiments, the object of the present invention is completely and effectively achieved. Those skilled in the art can understand that the present invention includes but is not limited to the content described in the drawings and the above specific embodiments. Although the present invention has been described with respect to the currently considered most practical and preferred embodiments, it should be understood that the present invention is not limited to the disclosed embodiments, and any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A laminated tie rod fastening energy storage flywheel rotor structure, characterized in that: include: The upper long shaft is used to provide upper support and power transmission for the flywheel rotor, and its lower end is coaxially fixedly connected to the top surface of the upper pressure plate; The upper platen has a flat bottom surface, a top surface thickness that gradually decreases from the inside to the outside in the radial direction, a raised step is provided at the center of the top surface, and dovetail grooves are evenly provided at the outer edge of the circumference; The circular plate stack is composed of a plurality of coaxially stacked circular plates, and the outer edge of each circular plate is uniformly provided with dovetail grooves matching the position and shape of the dovetail groove of the upper pressure plate; The lower pressure plate has a flat top surface, a bottom surface thickness that gradually becomes thinner from the inside to the outside, a raised step is provided at the center of the bottom surface, and dovetail grooves matching the position and shape of the dovetail grooves of the circular plate are provided at the outer edge of the circumference; The lower long shaft is used to provide lower support and power transmission for the flywheel rotor, and its upper end is coaxially fixedly connected to the bottom surface of the lower pressure plate; as well as The ladder-arc shaped pull rods are distributed along the circumference and their number corresponds to the dovetail groove. Each pull rod passes through the dovetail groove channel of the lower pressure plate, the circular plate stack and the upper pressure plate from bottom to top. Its cross-sectional shape fits tightly with the two side surfaces of the dovetail groove. The ends are fastened to the upper and lower pressure plates and the circular plate stack into an integral structure through locking components.

2. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 1 is characterized in that: The shapes of the upper and lower pressure plates are designed to be variable thickness structures with approximately equal stress design. The thickness of the top surface of the upper pressure plate and the bottom surface of the lower pressure plate gradually becomes thinner from the inside to the outside along the radial direction. The thickness variation curve is calculated and determined based on the operating speed and energy storage capacity requirements of the flywheel rotor.

3. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 1 is characterized in that: The ends of the upper and lower long shafts are provided with flange parts, a raised part is provided at the center of the flange part, and a plurality of connecting holes are provided in the circumferential direction of the flange part; a central positioning hole is provided on the raised steps of the upper and lower pressure plates, and a plurality of threaded holes corresponding to the connecting holes are provided on the outer circles of the central positioning hole, and the axial depth of each threaded hole does not exceed the radial thickness of the outer circle of the raised step; the raised parts of the upper and lower long shafts are interference fit with the central positioning holes of the upper and lower pressure plates, and coaxial positioning and fixed connection are achieved through bolt connection based on the corresponding connecting holes and threaded holes.

4. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 1 is characterized in that: The thickness of a single layer of circular plates in the circular plate stack is 10-100 mm, the diameter is 500-2000 mm, the number is 3-30, and the materials of the circular plates are the same or different. The contact surface roughness Ra ≤ 1.6 μm is ensured by fine grinding between the circular plates.

5. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 4 is characterized in that: In the circular plate stack, the thickness of each circular plate gradually increases from the two ends to the middle along the axial direction. The circular plate located in the middle of the axial direction has the largest thickness, and the circular plates located at the two ends have the smallest thickness. The thickness variation of the circular plates is designed according to a preset gradient increasing rule, and the circular plate stack as a whole forms a gradient variable thickness arrangement structure.

6. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 1, characterized in that: The trapezoidal arc shaped pull rod and the locking assembly at its end are made of lightweight and high-strength titanium alloy material. The cross-sectional shape of the pull rod is designed to be trapezoidal arc and fits tightly with the two side surfaces of the dovetail groove.

7. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 6 is characterized in that: The locking assembly at the end of the ladder-arc special-shaped pull rod is a locking nut, and its end face is provided with an anti-loosening serrated structure. The preload force is controlled to ensure a tight fit between the upper pressure plate, the circular plate stack and the lower pressure plate, and the preload force of each pull rod is kept consistent. At the same time, a preload force regular detection and adjustment mechanism is provided to ensure that the flywheel rotor maintains stable structural stiffness and dynamic balance performance during long-term use.

8. The laminated tie rod fastening energy storage flywheel rotor structure according to claim 1, characterized in that: The number of dovetail grooves of the upper pressure plate, the circular plate stack and the lower pressure plate is adjusted between 8 and 9 according to actual application requirements, evenly distributed along the circumferential direction, and the opening is toward the radial outer side of the circular plate; and the cross-sectional shape of the dovetail groove is trapezoidal as a whole, the inclination angle of the side wall is 45°~60°, the radius of the groove bottom fillet R≥2mm, and the depth and width are optimized according to the size of the flywheel and the operating speed.

9. An assembly method for fastening a flywheel rotor structure for energy storage by using laminated tie rods as described in any one of claims 1 to 8, characterized in that: include: SS1. Component preparation: inspect and confirm that the dimensional accuracy and surface quality of the upper long shaft, upper pressure plate, each round plate, lower pressure plate, lower long shaft, multiple ladder arc special-shaped tie rods and locking components meet the design requirements; SS2. Positioning and installation of the pressure plate and the long shaft: respectively coaxially fix the upper long shaft and the upper pressure plate, and the lower long shaft and the lower pressure plate, to ensure that the coaxiality error is less than the preset threshold; SS3. Pre-alignment assembly of circular plate stacking: Multiple circular plates are coaxially stacked between the upper platen and the lower platen, and the dovetail grooves on the outer edges of each circular plate are ensured to form a continuous circumferential channel with the dovetail grooves of the upper platen and the lower platen through positioning tooling, and the cumulative circumferential deviation does not exceed the preset threshold; SS4. Insertion and fitting of the ladder-arc special-shaped tie rod: insert the ladder-arc special-shaped tie rod upward from the dovetail groove of the lower pressure plate along the circumferential direction, and pass through the dovetail groove of the circular plate laminate and the dovetail groove of the upper pressure plate in sequence, and ensure that the cross section of the tie rod fits tightly with the two sides of each dovetail groove, and the fitting gap is less than the preset threshold; SS5. Axial preload and locking: Install a locking assembly on the upper end of the ladder arc profiled tie rod, apply axial preload through torque control, make the contact surface pressure of the upper platen, circular plate stack and lower platen evenly distributed to 20-50MPa, and use an anti-loosening structure to lock the nut to prevent loosening; SS6. Quality Inspection: Perform dynamic balancing test, dimension inspection and preload verification on the assembled flywheel rotor structure to ensure that it meets the design requirements for dynamic balancing accuracy and structural rigidity.

10. A flywheel energy storage system, characterized in that: The invention comprises a laminated tie rod fastening energy storage flywheel rotor structure as described in any one of claims 1 to 8.

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