A resonance-free modular quasi-zero stiffness vibration isolator

Abstract

This invention discloses a modular quasi-zero stiffness vibration isolator without resonance peaks, belonging to the field of low-frequency passive vibration isolation technology. It includes a base, with a friction adjustment mechanism and a curved beam quasi-zero stiffness parallel mechanism sequentially arranged from top to bottom at the center of the base. A connecting rod structure is arranged at the center of the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism. An end cap is provided at the upper end of the base, and a base plate is provided at the bottom end of the base. The friction adjustment mechanism includes a knurled threaded disc located at the top, with the bottom end of the knurled threaded disc connected to a sliding friction structure. The curved beam quasi-zero stiffness parallel mechanism includes several sets of quasi-zero stiffness structures arranged in parallel from top to bottom. This invention utilizes the aforementioned modular quasi-zero stiffness vibration isolator without resonance peaks, which provides moderate frictional damping to suppress resonance peaks under vibration excitation and reduces the impact on the system's vibration isolation transmissibility. Under impact excitation, it increases damping to rapidly attenuate impact energy, while maintaining a simple and compact structure.

Description

Technical Field

[0001] This invention relates to the field of low-frequency passive vibration isolation technology, and in particular to a modular quasi-zero stiffness vibration isolator with no resonance peak. Background Technology

[0002] With the rapid development of electronic technology, electronic equipment systems generally adopt highly integrated designs and are widely used in transportation platforms such as automobiles, ships, and aircraft. However, the working environments of vehicles, ships, and aircraft are extremely harsh. Electronic equipment systems must not only withstand long-term low-frequency vibration excitation but also cope with the coupling effects of complex loads such as impacts and random disturbances. This can easily lead to a decrease in the measurement accuracy of internal components and a shortened service life, severely restricting the stable operation of electronic equipment. Traditional linear vibration isolation systems are limited by the inherent contradiction between stiffness and load-bearing capacity, making it difficult to achieve effective low-frequency vibration control while ensuring sufficient load-bearing capacity, and thus failing to meet the vibration isolation requirements of integrated electronic equipment. Quasi-zero stiffness vibration isolators, as a typical type of nonlinear vibration isolation device, possess unique mechanical characteristics of high static and low dynamic values. They can significantly reduce the natural frequency of the system while meeting heavy-load requirements, providing an ideal solution for low-frequency vibration isolation.

[0003] However, existing quasi-zero stiffness vibration isolators still face many technical bottlenecks that urgently need to be addressed: First, due to their nonlinear characteristics, these isolators are prone to generating significant resonance peaks in the resonant frequency band, which greatly reduces the measurement accuracy and reliability of electronic equipment; Second, traditional quasi-zero stiffness vibration isolators generally lack efficient energy dissipation components, making it difficult to quickly dissipate impact energy when faced with impact vibrations, which can easily lead to structural damage to the isolated equipment; Third, most existing products suffer from defects such as complex structures, high space occupancy rates, and limited load adaptability, which severely restrict their large-scale application in the engineering field. Summary of the Invention

[0004] The purpose of this invention is to provide a modular quasi-zero stiffness vibration isolator without resonance peaks, which can provide moderate frictional damping to suppress resonance peaks under vibration excitation and reduce the impact on the vibration isolation transmission rate of the system. Under impact excitation, it can increase damping to quickly attenuate impact energy. At the same time, it has a simple and compact structure, and the load can be adjusted as needed to meet the vibration isolation requirements of vehicle-mounted, ship-mounted, and airborne electronic equipment.

[0005] To achieve the above objectives, the present invention provides a modular quasi-zero stiffness vibration isolator without resonance peaks, comprising a base, wherein a friction adjustment mechanism and a curved beam quasi-zero stiffness parallel mechanism are arranged sequentially from top to bottom at the center of the base, and a connecting rod structure is arranged at the center of the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism, the connecting rod structure being used to connect the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism, an end cap is provided at the upper end of the base, and a base plate is provided at the bottom end of the base; The friction adjustment mechanism includes a knurled threaded disc located at the top, the bottom of which is connected to the sliding friction structure. The curved beam quasi-zero stiffness parallel mechanism includes several sets of quasi-zero stiffness structures arranged in parallel from top to bottom. Both the sliding friction structure and the quasi-zero stiffness structure are located inside the base.

[0006] Preferably, the sliding friction structure includes an annular curved friction disk disposed inside the base. The annular curved friction disk is provided with a sliding friction component inside. The cross-sectional profile of the annular curved friction disk is a straight section in the middle and semi-circular arc sections at both ends. The straight section in the middle is suitable for small amplitude vibration conditions and provides low damping characteristics, while the semi-circular arc sections at both ends are suitable for large amplitude vibration and impact vibration conditions and provide high damping characteristics.

[0007] Preferably, the sliding friction assembly includes a mounting base located inside the annular curved friction disk. The mounting base has a cylindrical cavity and several radial grooves inside. The radial grooves are arranged and evenly distributed along the circumference of the cylindrical cavity, and the cylindrical cavity and the radial grooves are arranged correspondingly.

[0008] Preferably, the mounting base is provided with several guide sleeves, and a friction head is slidably embedded in the guide sleeve. One end of the friction head that protrudes from the guide sleeve is provided with a circular friction surface. The circular friction surface contacts the annular curved friction disk to form a friction pair. The other end of the friction head is provided with a shoulder. The end of the friction head with the shoulder is connected to one end of the synchronous slider through a pressure spring. The synchronous slider is slidably disposed in a radial groove. The top end of the synchronous slider is provided with several teeth. The bottom end of the knurled threaded disk is provided with an Archimedean spiral groove. The teeth are meshed with the Archimedean spiral groove.

[0009] Preferably, the edge of the top disc with knurled threads is machined with an anti-slip knurled texture, which is used to increase the friction when the hand rotates.

[0010] Preferably, the quasi-zero stiffness structure includes an annular support base disposed inside the base, an annular boss disposed at the center of the annular support base, and a plurality of curved beam quasi-zero stiffness units disposed in an annular array between the annular boss and the annular support base, and the annular boss of the uppermost quasi-zero stiffness structure is connected to the bottom end of the mounting base.

[0011] Preferably, the curved beam quasi-zero stiffness unit is manufactured using an integrated molding process. One end of the curved beam quasi-zero stiffness unit is connected to the annular boss through a straight beam fixing plate. The other end of the curved beam quasi-zero stiffness unit located at the bottom layer is connected to the base through a straight beam fixing plate. The other end of each layer of curved beam quasi-zero stiffness unit above the bottom layer is connected to the next layer of annular support base through a straight beam fixing plate.

[0012] Preferably, the curved beam quasi-zero stiffness unit includes a first circular arc segment, a straight beam segment, and a second circular arc segment that are smoothly connected in sequence. The first circular arc segment and the second circular arc segment are respectively connected to the straight beam fixing plates at both ends of the curved beam quasi-zero stiffness unit.

[0013] Preferably, the connecting rod structure includes a threaded connecting rod, which passes through a knurled threaded disc, a mounting base, and several annular bosses from top to bottom, connecting the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism together. A round nut is provided at the top of the threaded connecting rod, and an elastic washer for compensating for the threaded connection gap is provided between the round nut and the knurled threaded disc.

[0014] Preferably, the base plate is embedded at the bottom end of the base, the top end of the base plate is embedded with a lower buffer rubber pad, the top end of the mounting base is embedded with an upper buffer rubber pad, and the upper buffer rubber pad is located between the end cover and the mounting base, and between the knurled threaded disc and the mounting base.

[0015] The advantages and positive effects of the modular quasi-zero stiffness vibration isolator without resonance peak described in this invention are as follows: 1. The vibration isolator designed in this invention has a load adjustment function. The modular design can adjust the vibration isolation quality by increasing or decreasing the number of quasi-zero stiffness units of the curved beam. 2. The vibration isolator designed in this invention can reduce undesirable resonance peaks. It combines adjustable friction damping and quasi-zero stiffness of curved beams in its design. By adjusting the friction damping, resonance peaks can be eliminated without affecting low-frequency vibration performance. 3. The vibration isolator designed in this invention can precisely control the friction damping. Through the Archimedes spiral tooth meshing adjustment, multiple synchronous sliders are driven to move synchronously and compress the pressure spring, thereby changing the normal pressure of the friction head and the annular curved friction disk, realizing the synchronous and precise adjustment of multi-end friction force. Moreover, this adjustment process does not require disassembling the vibration isolator, which significantly improves the convenience of operation and work efficiency. 4. The vibration isolator designed in this invention has a simple structure, is easy to disassemble and maintain, and has strong design flexibility; 5. This invention achieves the dual characteristics of adjustable load and adjustable friction damping of the quasi-zero stiffness vibration isolator by organically combining the modular curved beam quasi-zero stiffness unit, the special structure annular curved surface friction disk and the adjustable friction structure. While ensuring the low-frequency vibration isolation effect, it effectively eliminates undesirable resonance peaks, has the ability to adapt to vibration and impact loads, and has a wider range of applications.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks according to the present invention; Figure 2 This is a cross-sectional view of an embodiment of a modular quasi-zero stiffness vibration isolator with no resonance peak according to the present invention; Figure 3 This is a schematic diagram of a curved beam quasi-zero stiffness parallel structure according to an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks of the present invention; Figure 4 This is a schematic diagram of a curved beam quasi-zero stiffness unit structure according to an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks of the present invention. Figure 5 The above are load curves of different numbers of curved beam quasi-zero stiffness units in an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks according to the present invention. Figure 6 This is a comparison diagram of the force-displacement curves of the curved beam quasi-zero stiffness parallel mechanism of the present invention and the traditional linear vibration isolation structure. Figure 7 This is a comparison diagram of the vibration isolation performance of the curved beam quasi-zero stiffness parallel mechanism of the present invention and the traditional linear vibration isolation structure; Figure 8 This is a schematic diagram of the friction adjustment mechanism of an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks according to the present invention; Figure 9 This is a schematic diagram of the sliding friction structure of an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks according to the present invention; Figure 10 This is a schematic diagram showing the connection between the synchronous slider and the knurled threaded disc in an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks according to the present invention. Figure 11 This is a vibration isolation transmissivity curve of an embodiment of a modular quasi-zero stiffness vibration isolator without resonance peaks according to the present invention.

[0018] Figure label: 1. Round nut; 2. Elastic washer; 3. Knurled threaded disc; 4. End cap; 5. Annular curved friction disc; 6. Base; 7. Annular support base; 8. Archimedes spiral groove; 9. Curved beam quasi-zero stiffness unit; 10. Base plate; 11. Lower end buffer rubber pad; 12. Annular boss; 13. Teeth; 14. Mounting seat; 15. Guide sleeve; 16. Friction head; 17. Pressure spring; 18. Upper end buffer rubber pad; 19. Synchronous slider; 20. Threaded connecting rod; 21. Anti-slip knurled texture; 22. Straight beam fixing plate; 23. First arc segment; 24. Straight beam segment; 25. Second arc segment; 26. Shoulder. Detailed Implementation

[0019] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" 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 or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] In this application, unless otherwise defined, 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 application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0021] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] Example: like Figure 1 , Figure 2 As shown, the present invention discloses a modular quasi-zero stiffness vibration isolator without resonance peak, comprising a base 6. A friction adjustment mechanism and a curved beam quasi-zero stiffness parallel mechanism are arranged sequentially from top to bottom at the center of the base 6. A connecting rod structure is arranged at the center of the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism. The connecting rod structure is used to connect the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism. An end cap 4 is provided at the upper end of the base 6, and a base plate 10 is provided at the bottom end of the base 6.

[0023] This modular quasi-zero stiffness vibration isolator with no resonance peak uses a base 6 as its base. The end of the base 6 has external threads for threaded connection with the end cap 4, and four through holes at the bottom for mounting and fixing. A base plate 10 is embedded in the bottom of the base 6, and a lower buffer rubber pad 11 is embedded in the top of the base plate 10. A threaded hole is located in the center of the bottom of the base 6 for mounting the base plate 10. The base plate 10 has eight through holes, facilitating the use of a special tool to fasten the base plate 10 to the base 6 via threads.

[0024] The quasi-zero stiffness parallel mechanism of the curved beam is the core functional component for achieving low-frequency vibration isolation in this invention, and its design directly determines the quasi-zero stiffness characteristics and load-bearing stability of the vibration isolation system. For example... Figure 3 As shown, in this embodiment, the curved beam quasi-zero stiffness parallel mechanism includes two sets of quasi-zero stiffness structures arranged in parallel from top to bottom. To ensure the uniformity of load transfer and structural stress balance, the quasi-zero stiffness structures adopt a ring-shaped uniformly distributed layout and are fixedly installed in a symmetrical manner in the upper and lower layers to form a stable parallel load-bearing system. The quasi-zero stiffness structure includes an annular support base 7 disposed inside the base 6, with an annular boss 12 disposed at the center of the annular support base 7. Several curved beam quasi-zero stiffness units 9 are arranged in a ring array between the annular boss 12 and the annular support base 7. The annular boss 12 of the quasi-zero stiffness structure located in the first layer is connected to the bottom end of the mounting base 14.

[0025] In this embodiment, the curved beam quasi-zero stiffness parallel mechanism includes 16 uniformly sized curved beam quasi-zero stiffness units 9, divided into two parallel groups, with 8 curved beam quasi-zero stiffness units 9 in each group. One end of the curved beam quasi-zero stiffness unit 9 is connected to the annular boss 12 via a straight beam fixing plate 22. The other end of the curved beam quasi-zero stiffness unit 9 in the second layer is connected to the base 6 via a straight beam fixing plate 22. The other end of the curved beam quasi-zero stiffness unit 9 in the first layer is connected to the annular support base 7 in the second layer via a straight beam fixing plate 22. In this embodiment, the bottom of the curved beam quasi-zero stiffness unit 9 in the second layer is precisely fixed to the inner boss end face of the base 6 with high-strength fastening screws, and its upper end is firmly locked to the annular boss 12 in the second layer with positioning screws of the same specification. The bottom of the curved beam quasi-zero stiffness unit 9 in the first layer is reliably connected to the annular support base 7 in the second layer with the same screw fastening method, and its upper end is stably fixed to the annular boss 12 in the first layer with positioning screws of the same specification.

[0026] The curved beam quasi-zero stiffness element 9 is manufactured using an integrated molding process, and its material is spring steel 65Mn, which combines excellent elastic recovery performance with high strength load-bearing capacity. For example... Figure 4As shown, the curved beam quasi-zero stiffness unit 9 includes a first circular arc segment 23, a straight beam segment 24, and a second circular arc segment 25 that are smoothly connected in sequence. The first circular arc segment 23 and the second circular arc segment 25 are respectively connected to the straight beam fixing plates 22 at both ends of the curved beam quasi-zero stiffness unit 9. The curvature and dimensions of the three structural segments of the curved beam quasi-zero stiffness unit 9 have been precisely optimized to ensure that the unit can form ideal quasi-zero stiffness mechanical properties under stress. The two ends of the curved beam quasi-zero stiffness unit 9 extend outward to form straight beam fixing plates 22. Each straight beam fixing plate 22 has two positioning and fixing holes. This design not only simplifies the assembly process between the unit and the mounting base, but also ensures the coaxiality and stability of the connection, avoiding the impact of assembly deviations on mechanical properties. The curved beam quasi-zero stiffness unit 9 adopts an integrated design, abandoning the positive and negative stiffness superposition mode of traditional quasi-zero stiffness structures, significantly simplifying the structural complexity, and through modular design, it can easily realize load adjustment, making it more adaptable. Figure 5 As shown, in actual use, the overall load capacity of the vibration isolator can be precisely matched with the load requirements of the vibration isolator by simply increasing or decreasing the number N of the quasi-zero stiffness unit 9 of the curved beam, thereby achieving load adaptation adjustment without redesigning or modifying the core structure of the vibration isolator.

[0027] like Figure 6 As shown in the figure, under the same static displacement and load conditions at the dot, the stiffness (slope) of the curved beam quasi-zero stiffness parallel mechanism of this invention is much lower than that of the traditional linear vibration isolation structure. This is precisely its core advantage in achieving efficient low-frequency vibration isolation. A comparison of the vibration isolation performance of the two types of vibration isolators is shown below. Figure 7 Data shows that the initial vibration isolation frequency of the curved beam quasi-zero stiffness parallel mechanism can be reduced to 0.9Hz, while the initial vibration isolation frequency of the linear vibration isolation structure is as high as 10Hz, which fully demonstrates the outstanding effectiveness of the curved beam quasi-zero stiffness parallel mechanism in suppressing ultra-low frequency vibration.

[0028] The friction adjustment mechanism is the core component of this invention for achieving adaptive and precise damping control, such as... Figure 8 As shown, the friction adjustment mechanism includes a knurled disc 3 located at the top, with its bottom end connected to the sliding friction structure. Both the sliding friction structure and the quasi-zero stiffness structure are located inside the base 6. The sliding friction structure includes an annular curved friction disc 5 disposed inside the base 6, with a sliding friction assembly disposed inside the annular curved friction disc 5.

[0029] like Figure 2 , Figure 9As shown, the sliding friction assembly includes a mounting base 14 located inside the annular curved friction disk 5. The mounting base 14 has a cylindrical cavity and several radial grooves inside. The radial grooves are arranged circumferentially along the cylindrical cavity and are evenly distributed, with the cylindrical cavity corresponding to the radial grooves. Several guide sleeves 15 are provided on the mounting base 14, and friction heads 16 are slidably embedded within the guide sleeves 15. One end of the friction head 16 extending out of the guide sleeve 15 has a circular friction surface, which contacts the annular curved friction disk 5 to form a friction pair. The other end of the friction head 16 has a shoulder 26, and this end is connected to one end of a synchronous slider 19 via a pressure spring 17. The synchronous slider 19 is slidably positioned within the radial grooves. The top end of the synchronous slider 19 has several teeth 13, and the bottom end of the knurled threaded disk 3 has an Archimedean spiral groove 8, with the teeth 13 meshing with the Archimedean spiral groove 8.

[0030] like Figure 2 , Figure 10 As shown, the friction surface cross-section of the annular curved friction disk 5 adopts a combined contour design of "a straight section in the middle and semi-circular arc sections at both ends," which has the ability to adaptively adjust the vibration amplitude and damping: the straight section in the middle is suitable for small-amplitude vibration conditions, providing low-damping characteristics through stable and slight contact between the friction pairs, ensuring the vibration isolation transmission efficiency of the isolator in conventional vibration scenarios; the semi-circular arc sections at both ends are designed for large-amplitude vibration and impact vibration conditions, providing high-damping characteristics through increased contact normal pressure of the friction pairs, achieving rapid dissipation of impact energy and effective suppression of large-amplitude vibration. The bottom of the annular curved friction disk 5 is embedded and fixed on the first-layer annular support base 7, and the top is pressed and limited by the end cap 4 to form an axial constraint, ensuring that the annular curved friction disk 5 always maintains a stable assembly posture under vibration and impact conditions, avoiding axial displacement that could lead to contact failure of the friction pairs.

[0031] Mounting base 14 serves as the mounting base for the friction adjustment mechanism, and its structural design combines guiding and assembly functions. In this embodiment, mounting base 14 has four radial grooves evenly distributed at 90° to provide precise radial guidance for the synchronous slider 19; it also has cylindrical cavities corresponding to the radial grooves. The friction head 16, guide sleeve 15, and pressure spring 17 are all coaxially assembled in the cylindrical cavity according to the assembly sequence. Specifically, the assembly relationship is as follows: the friction head 16 is slidably embedded in the guide sleeve 15, and its top circular friction surface is in close contact with the friction surface of the annular curved friction disk 5 to ensure the reliability of the friction pair contact; the bottom of the friction head 16 has an integrally formed shoulder 26, which abuts against one end of the guide sleeve 15, and the other end of the guide sleeve 15 is fastened to the preset threaded hole of the mounting base 14 of the friction head 16 by screws, forming axial positioning and ensuring that the preload of the pressure spring 17 can be stably transmitted to the friction pair. Figure 2 , Figure 10As shown, the synchronous slider 19 adopts a square structure adapted to the radial groove and is embedded in the radial groove of the mounting base 14, allowing for smooth radial linear sliding along the groove without jamming. The top of the synchronous slider 19 is precision-machined to form a threaded groove adapted to the transmission requirements, with teeth 13 forming between the threaded grooves to ensure smooth meshing transmission. The bottom of the knurled threaded disc 3 is machined with an Archimedean spiral groove 8 that meets the transmission accuracy requirements. This Archimedean spiral groove 8 precisely meshes with the teeth 13 of the four synchronous sliders 19, forming a high-efficiency transmission pair. When the knurled threaded disc 3 is manually rotated, its rotational motion is converted into synchronous radial linear motion of the four synchronous sliders 19 through the meshing grooves, thereby achieving synchronous adjustment of the pre-compression range of the four sets of pressure springs 17, ultimately achieving precise and controllable adjustment of the friction damping value. Figure 11 The diagram shows the vibration transmission rate curve of the vibration isolator of this invention. By precisely controlling the friction damping, the resonance peak of the quasi-zero stiffness parallel mechanism of the curved beam can be effectively suppressed, thereby improving the stability and vibration isolation performance of the vibration isolator.

[0032] The top disc of the knurled disc 3 has an anti-slip knurled texture 21 on its edge. The anti-slip knurled texture 21 is used to increase the friction when the hand rotates, so that the operator can manually and accurately rotate it without the need for special tools, and realize convenient adjustment and real-time calibration of the friction damping value.

[0033] The connecting rod structure includes a threaded connecting rod 20, which passes sequentially from top to bottom through a knurled threaded disc 3, a mounting base 14, and several annular bosses 12, connecting the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism together. The upper and lower curved beam quasi-zero stiffness units 9 are connected to the threaded connecting rod 20 through the annular bosses 12, working together to bear the load of the vibration isolation object and provide quasi-zero stiffness characteristics.

[0034] In addition, to ensure the stability of the friction damping value under vibration and impact conditions, the knurled threaded disc 3 is fastened to the threaded connecting rod 20 by a combination of a round nut 1 and an elastic washer 2. The elastic washer 2 can effectively compensate for the threaded connection gap, and the round nut 1 provides reliable locking force. This dual protection can effectively suppress the loosening of the threads caused by vibration, avoid unexpected drift of the friction damping value, and ensure the stability of the damping performance of the vibration isolator during long-term operation.

[0035] To further enhance the structural reliability and damage resistance of the vibration isolator under extreme impact conditions, and to prevent irreversible plastic deformation of the curved beam quasi-zero stiffness unit 9 due to excessive axial displacement under large impact loads, while also preventing direct rigid collisions between the second-layer annular boss 12 and the base plate 10, and between the mounting base 14 and the end cap 4, thus avoiding component damage, this design specifically incorporates a dual buffer protection structure: fixed buffer rubber pads (upper buffer rubber pad 18 and lower buffer rubber pad 11) are embedded in the recessed groove of the base plate 10 and at the top of the mounting base 14. The upper buffer rubber pad 18 is embedded at the top of the mounting base 14, located between the end cap 4 and the mounting base 14, and between the knurled threaded disc 3 and the mounting base 14. The interior of the base plate 10 is concave to accommodate the lower buffer rubber pad 11. The buffer rubber pad is made of highly elastic and fatigue-resistant rubber material. It can not only form a rigid limit through its own elastic deformation to accurately limit the overtravel displacement of the quasi-zero stiffness unit 9 of the curved beam and prevent it from exceeding the elastic deformation range, but also utilize the viscoelastic properties of the rubber material to effectively absorb and attenuate part of the impact energy during the collision contact process, reduce the instantaneous force of the impact load on the core component of the vibration isolator and the object being isolated, and significantly improve the impact resistance and service life of the entire vibration isolation system.

[0036] The main implementation scheme of the modular quasi-zero stiffness vibration isolator without resonance peak of the present invention includes the following steps: (1) Load matching adjustment: First, the effective load parameters of the vibration isolation object need to be accurately obtained through professional testing equipment. Based on the measured load data, the load matching adjustment is carried out by increasing or decreasing the number of the quasi-zero stiffness unit 9 of the curved beam, taking advantage of the modular combination of the curved beam quasi-zero stiffness unit 9. This adjustment method does not require modification of the core structure of the vibration isolator, and can make the overall load bearing capacity of the vibration isolator accurately matched with the actual load requirements of the vibration isolation object, thereby laying a reliable bearing foundation for subsequent high-efficiency low-frequency vibration isolation and ensuring that the vibration isolator can stably perform low-frequency vibration isolation performance under the target load conditions.

[0037] (2) Precise adjustment of friction damping: First, it is necessary to determine the optimal friction damping force required to suppress the resonance peak. Based on the nonlinear dynamic equation of friction damping force, the nonlinear stiffness parameters of the system are obtained by fitting the nonlinear quasi-zero stiffness characteristic curve; then, parametric simulation analysis is carried out by substituting different preset friction damping force values ​​to screen out the optimal friction damping force threshold that can effectively suppress the resonance peak amplitude and minimize the impact on the vibration isolation performance of the system. Subsequently, the pressure spring 17 is pre-compressed and adjusted by rotating the knurled disc 3 to apply a suitable axial normal pressure; according to the friction force calculation formula (friction force = friction coefficient × normal pressure), combined with the friction coefficient of the steel-steel contact surface (taken as 0.15), the target friction damping force can be accurately obtained to complete the initial damping adjustment.

[0038] (3) Assembly, Operation and Fine Calibration: The vibration isolation object is fixed to the vibration isolator that has completed preliminary debugging through the threaded connecting rod 20. The load force is transmitted to the quasi-zero stiffness unit 9 of the curved beam through the threaded connecting rod 20, so that the quasi-zero stiffness unit 9 of the curved beam is compressed to the quasi-zero stiffness working state. At this time, the friction head 16 is exactly at the center of the straight section of the annular curved friction disk 5, and the vibration isolator officially enters the vibration isolation working mode. Due to factors such as machining accuracy and assembly error, there is a certain deviation between the theoretical design value and the actual working condition. Therefore, it is necessary to observe the resonance response during operation: if there is still an obvious resonance amplification phenomenon, the knurled threaded disk 3 can be manually rotated for precise fine adjustment, and the pre-compression of the pressure spring 17 can be slowly increased, thereby gradually increasing the friction damping force until the resonance peak is completely suppressed; at the same time, it is necessary to monitor the consistency between the initial vibration isolation frequency and the theoretical design value in real time to avoid excessive friction force from having an adverse effect on the vibration isolation performance of the frequency band after the resonance frequency. After the debugging is completed and the standard is met, tighten the round nut 1 to the current position of the knurled threaded disc 3, and use the elastic washer 2 to compensate for the thread clearance to ensure that the friction damping value does not change unexpectedly under long-term vibration conditions, thus ensuring the stable operation of the vibration isolation system.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A modular quasi-zero stiffness vibration isolator with no resonance peak, characterized in that: The base includes a friction adjustment mechanism and a curved beam quasi-zero stiffness parallel mechanism arranged sequentially from top to bottom at its center. A connecting rod structure is arranged at the center of the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism. The connecting rod structure is used to connect the friction adjustment mechanism and the curved beam quasi-zero stiffness parallel mechanism. An end cap is provided at the upper end of the base, and a base plate is provided at the bottom end of the base. The friction adjustment mechanism includes a knurled threaded disc located at the top, the bottom of which is connected to the sliding friction structure. The curved beam quasi-zero stiffness parallel mechanism includes several sets of quasi-zero stiffness structures arranged in parallel from top to bottom. Both the sliding friction structure and the quasi-zero stiffness structure are located inside the base.

2. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 1, characterized in that: The sliding friction structure includes an annular curved friction disk disposed inside the base. The annular curved friction disk contains a sliding friction component. The cross-sectional profile of the annular curved friction disk is a straight section in the middle and semi-circular arc sections at both ends. The straight section in the middle is suitable for small amplitude vibration conditions and provides low damping characteristics, while the semi-circular arc sections at both ends are suitable for large amplitude vibration and impact vibration conditions and provide high damping characteristics.

3. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 2, characterized in that: The sliding friction assembly includes a mounting base located inside an annular curved friction disk. The mounting base has a cylindrical cavity and several radial grooves inside. The radial grooves are arranged and evenly distributed along the circumference of the cylindrical cavity, and the cylindrical cavity and the radial grooves are arranged correspondingly.

4. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 3, characterized in that: The mounting base is provided with several guide sleeves, and a friction head is slidably embedded in the guide sleeve. One end of the friction head that protrudes from the guide sleeve is provided with a circular friction surface. The circular friction surface contacts the annular curved friction disk to form a friction pair. The other end of the friction head is provided with a shoulder. The end of the friction head with the shoulder is connected to one end of the synchronous slider through a pressure spring. The synchronous slider is slidably set in a radial groove. The top of the synchronous slider is provided with several teeth. The bottom end of the knurled threaded disk is provided with an Archimedean spiral groove. The teeth are meshed with the Archimedean spiral groove.

5. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 1, characterized in that: The top disc of the knurled disc has an anti-slip knurled texture on its edge, which increases friction when the hand rotates it.

6. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 2, characterized in that: The quasi-zero stiffness structure includes an annular support base inside the base, an annular boss at the center of the annular support base, and several curved beam quasi-zero stiffness units arranged in an annular array between the annular boss and the annular support base. The annular boss of the uppermost quasi-zero stiffness structure is connected to the bottom end of the mounting base.

7. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 6, characterized in that: The curved beam quasi-zero stiffness unit is manufactured using an integrated molding process. One end of the curved beam quasi-zero stiffness unit is connected to the annular boss through a straight beam fixing plate. The other end of the curved beam quasi-zero stiffness unit located at the bottom layer is connected to the base through a straight beam fixing plate. The other end of each layer of curved beam quasi-zero stiffness unit above the bottom layer is connected to the annular support base of the next layer of curved beam quasi-zero stiffness unit through a straight beam fixing plate.

8. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 7, characterized in that: The curved beam quasi-zero stiffness unit includes a first circular arc segment, a straight beam segment, and a second circular arc segment that are smoothly connected in sequence. The first and second circular arc segments are respectively connected to the straight beam fixing plates at both ends of the curved beam quasi-zero stiffness unit.

9. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 8, characterized in that: The connecting rod structure includes a threaded connecting rod, which passes through a knurled threaded disc, a mounting base, and several annular bosses from top to bottom, connecting the friction adjustment mechanism and the quasi-zero stiffness parallel mechanism of the curved beam together. A round nut is provided at the top of the threaded connecting rod, and an elastic washer for compensating for the threaded connection gap is provided between the round nut and the knurled threaded disc.

10. The modular quasi-zero stiffness vibration isolator without resonance peaks according to claim 2, characterized in that: The base plate is embedded at the bottom of the base, and the top of the base plate is embedded with a lower buffer rubber pad. The top of the mounting base is embedded with an upper buffer rubber pad. The upper buffer rubber pad is located between the end cover and the mounting base, and between the knurled threaded disc and the mounting base.

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