A pre-press adjustable quasi-zero stiffness vibration isolator
By using an umbrella-shaped quasi-zero stiffness spring structure and an integrated preload adjustment mechanism, combined with multiple damping sand hammers, the problem of fixed stiffness and inconvenient adjustment in traditional vibration isolation devices is solved. This achieves efficient low-frequency vibration isolation and multi-dampening energy dissipation, adapting to the vibration control needs of multiple scenarios and meeting the high-precision vibration isolation requirements of high-end equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN POWER TRANSMISSION & TRANSFORMATION PROJECT ENVIRONMENTAL IMPACT CONTROL TECHN CENT CO LTD
- Filing Date
- 2026-04-21
- Publication Date
- 2026-06-05
AI Technical Summary
Traditional vibration isolation devices have insufficient low-frequency vibration isolation performance, fixed stiffness and cannot be adjusted. Existing quasi-zero stiffness vibration isolators have complex structures, cumbersome preload adjustment, high cost and insufficient reliability, making it difficult to meet the high-precision vibration isolation requirements of high-end equipment.
The system employs a one-main-four-sub umbrella-shaped quasi-zero stiffness spring structure, combined with an integrated preload adjustment mechanism and a multi-damping sand hammer structure, to achieve precise adjustment of system stiffness and multi-dimensional damping energy dissipation. Through the coordinated work of the umbrella-shaped support system and damping components, the system improves low-frequency vibration isolation performance and structural reliability.
Significant optimization of vibration isolation performance has been achieved, stiffness adjustment flexibility has been greatly improved, damping energy dissipation capacity has been enhanced, structural reliability and economy have been improved, adapting to vibration control needs in multiple scenarios and meeting the high-precision vibration isolation requirements of high-end equipment.
Smart Images
Figure CN122148692A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of mechanical vibration control, and specifically relates to a quasi-zero stiffness vibration isolator with adjustable preload. Background Technology
[0002] In high-end industrial fields such as precision manufacturing, optical measurement, and ultra-precision testing, micro-vibrations in the environment can significantly affect the operational accuracy of equipment and the precision of measurement results, thus placing extremely stringent requirements on vibration control. Among these, the effectiveness of isolating low-frequency vibrations directly determines the actual performance of high-end equipment.
[0003] Traditional vibration isolation devices mostly employ a single spring damping structure, which generally suffers from insufficient low-frequency vibration isolation performance and fixed, unadjustable system stiffness, making it difficult to adapt to vibration isolation requirements under different operating conditions. While existing quasi-zero stiffness isolators can achieve low-frequency vibration isolation, their structural designs are typically complex, the preload adjustment process is cumbersome, their damping characteristics are singular, and some products suffer from high manufacturing costs and insufficient reliability. Furthermore, the stiffness adjustment range of these isolators is limited, making it impossible to flexibly adjust according to the weight of the isolated equipment and the characteristics of the vibration source, thus failing to meet the stringent requirements of high-precision vibration isolation for high-end equipment such as precision instruments and optical platforms. Summary of the Invention
[0004] This application provides a preload-adjustable quasi-zero stiffness vibration isolator. The isolator adopts a one-main-four-sub umbrella-shaped quasi-zero stiffness spring structure, combined with an integrated preload adjustment mechanism and a multi-damping sand hammer structure, to achieve precise and convenient adjustment of system stiffness. It also has excellent low-frequency vibration isolation performance and multi-damping energy dissipation capability. Furthermore, it has a compact structure, high reliability, and low manufacturing cost, and can effectively adapt to the vibration control needs of high-end equipment such as precision instruments and optical platforms.
[0005] To achieve the above objectives, this application provides a preload-adjustable quasi-zero stiffness vibration isolator, comprising a main load-bearing mechanism, four sets of secondary spring units, a preload adjustment mechanism, and four sets of damping sand hammer assemblies.
[0006] The main load-bearing mechanism consists of a central support rod connecting the upper and lower load-bearing plates, and is used to bear and transmit vertical loads; the bottom of the preload adjustment mechanism is set on the lower load-bearing plate, and the top is in close contact with the upper load-bearing plate, forming a stable axial constraint; the four sets of auxiliary spring units are arranged symmetrically in a 90° circumferential direction around the preload adjustment mechanism, forming an umbrella-shaped support system;
[0007] The four sets of damping sand hammer assemblies are symmetrically arranged on the lower surface of the upper bearing plate.
[0008] In one embodiment, the main bearing mechanism includes an upper bearing plate, a lower bearing plate, a central support rod, and a central main spring;
[0009] Both the upper and lower support plates have a central threaded hole, and the two ends of the central support rod are threaded to the central threaded hole respectively; the central main spring is sleeved on the outside of the central support rod, and its two ends are fixed to the lower surface of the upper support plate and the upper surface of the lower support plate respectively; the central support rod is a telescopic structure, which can realize the compression and extension adjustment of the axial height.
[0010] In one embodiment, the preload adjustment mechanism includes four sets of guide rails evenly fixed around the circumference of the lower support plate. A slider is slidably mounted on each set of guide rails. A column is vertically mounted on the slider. The upper end of the column passes through a circular hole on the slip ring and slides with it. A hinge seat is arranged circumferentially on the slip ring. The hinge seat is connected to the lower end of the secondary spring unit. The upper end of the secondary spring unit is hinged to the annular hinge seat. The annular hinge seat is fixed to the end of the central support rod near the upper support plate and is in close contact with the lower surface of the upper support plate.
[0011] In one embodiment, the slip ring is a replaceable structure, and slip rings of different sizes can be replaced according to vibration isolation requirements to change the adjustment range of the relative horizontal angle between the secondary spring unit and the lower bearing plate.
[0012] In one embodiment, the secondary spring unit includes a hinge joint, a secondary spring connecting piece, a secondary spring support rod, a secondary spring, and an adjusting nut;
[0013] There are two hinge joints, which are fixedly installed at the upper and lower ends of the auxiliary spring support rod, respectively. Both hinge joints are hinged to the annular hinge seat and the hinge seat of the slip ring respectively through cylindrical pins and snap rings. There are two auxiliary spring connecting pieces, which are placed at both ends of the auxiliary spring support rod. The auxiliary spring is sleeved on the outside of the auxiliary spring support rod, and its two ends abut against the two auxiliary spring connecting pieces respectively.
[0014] The secondary spring support rod is a telescopic structure, which works with the central support rod to adjust the relative horizontal angle between the rod and the lower bearing plate; the adjusting nut is threadedly connected to the lower end of the secondary spring support rod, and is used to change the relative position of the secondary spring connecting piece on the secondary spring support rod.
[0015] In one embodiment, the damping hammer assembly includes a damping hammer cover and a damping hammer cylinder. The damping hammer cylinder is a cylindrical cavity with an open top, filled with a damping mixture. The damping hammer cover covers and seals the upper opening of the damping hammer cylinder. The damping hammer cylinder is detached and fixed to the lower side of the upper support plate by screws.
[0016] In one embodiment, the damping mixture filling the cylindrical cavity of the damping hammer cylinder comprises, by mass percentage, 70%–80% quartz sand, 10%–20% cast iron particles, and 5%–10% damping powder.
[0017] In one embodiment, the natural frequency of the vibration isolator can be adjusted within the range of 0.8Hz to 1.2Hz, and the transmission rate for 10Hz vibration is less than 0.05, and the transmission rate for 50Hz vibration is less than 0.01.
[0018] A vibration isolation system includes at least three quasi-zero stiffness isolators, which are evenly arranged at the bottom of the equipment to be isolated.
[0019] Compared with the prior art, the beneficial effects of this application are:
[0020] 1. Significantly optimized vibration isolation performance: The present invention adopts an umbrella-shaped quasi-zero stiffness structure with the cooperation of main and auxiliary springs, which can accurately construct quasi-zero stiffness characteristics, greatly improve low-frequency vibration isolation capability, effectively broaden the applicable frequency band of vibration isolation, significantly reduce the vibration transmissibility across the entire frequency band, fully meet the stringent requirements of high-end precision equipment for micro-vibration control, and provide stable vibration isolation guarantee for high-precision operation of equipment.
[0021] 2. Significantly improved flexibility in stiffness adjustment: The integrated preload adjustment mechanism enables multi-level coordinated adjustment of system stiffness, making the adjustment operation convenient and more precise. It can flexibly adjust the system stiffness parameters according to the load characteristics and vibration source characteristics of the isolated equipment, effectively adapting to the differentiated vibration isolation needs in multiple scenarios and solving the defects of fixed stiffness and inconvenient adjustment of traditional vibration isolators.
[0022] 3. Significantly enhanced damping energy dissipation capacity: Equipped with a multi-damping energy dissipation structure, the vibration energy dissipation efficiency is greatly improved through the synergistic effect of rigid impact and viscous damping, and the vibration attenuation capacity is enhanced; the damping components adopt a detachable design, which can flexibly adjust the damping characteristics, further improving the dynamic stability and adaptability under complex working conditions.
[0023] 4. Dual improvement in structural reliability and economy: The overall modular layout ensures high precision in the fit of each component and uniform stress distribution, effectively reducing the risk of local stress concentration and significantly improving the fatigue resistance and long-term operational reliability of the structure; the core components all adopt conventional general mechanical structures, which are easy to process, install and maintain, greatly reducing manufacturing costs and making them suitable for industrial mass production and engineering applications.
[0024] 5. Expanded application scope: The multi-unit combined vibration isolation system built based on this vibration isolator can achieve all-round vibration isolation of the isolated equipment, effectively avoid the attenuation of vibration isolation effect caused by off-center loading, and can be widely adapted to the vibration control needs of high-end equipment in many fields such as precision testing, optical measurement, and high-end manufacturing. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a structural diagram of the vibration isolator, showing the assembly relationship of each component;
[0027] Figure 2 This is a structural diagram of the main load-bearing mechanism of the vibration isolator;
[0028] Figure 3 This is a top view of the umbrella spring structure of the vibration isolator, showing a symmetrical layout of one main spring and four auxiliary springs.
[0029] Figure 4 This is a structural diagram of a set of auxiliary spring units for a vibration isolator;
[0030] Figure 5 Detailed drawing of the preload adjustment mechanism for the vibration isolator;
[0031] Figure 6 This is a schematic diagram of the damping sand hammer structure of the vibration isolator.
[0032] Explanation of reference numerals in the attached drawings: 100, main bearing mechanism; 200, secondary spring unit; 300, preload adjustment mechanism; 400, damping sand hammer assembly; 101, upper bearing plate; 102, lower bearing plate; 103, central support rod; 104, central main spring; 201, hinge joint; 202, secondary spring connecting piece; 203, secondary spring support rod; 204, secondary spring; 205, adjusting nut; 301, annular hinge seat; 302, column; 303, slip ring; 304, slider; 401, damping sand hammer cover; 402, damping sand hammer cylinder. Detailed Implementation
[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.
[0034] See Figures 1 to 6 As shown, this application provides a preload-adjustable quasi-zero stiffness vibration isolator, including a main load-bearing mechanism 100, four sets of auxiliary spring units 200, a preload adjustment mechanism 300, and four sets of damping sand hammer assemblies 400.
[0035] The main load-bearing mechanism 100 is composed of a central support rod 103 connecting the upper load-bearing plate 101 and the lower load-bearing plate 102, and is used to bear and transmit vertical loads; the bottom of the preload adjustment mechanism 300 is set on the lower load-bearing plate 102, and the top is in close contact with the upper load-bearing plate 101, forming a stable axial constraint; four sets of auxiliary spring units 200 are arranged symmetrically in a 90° circumferential direction around the preload adjustment mechanism 300, forming an umbrella-shaped support system;
[0036] Four sets of damping sand hammer assemblies 400 are symmetrically arranged on the lower surface of the upper bearing plate 101.
[0037] Based on the vibration isolation data, the preload adjustment mechanism 300 is adapted and adjusted. After the preload value is set, the quasi-zero stiffness vibration isolator is placed in the working area. When external excitation is applied to the upper bearing plate 101, the central main spring 104 and the four sets of auxiliary springs 204 deform in tandem, and the preload adjustment mechanism 300 compensates for stiffness changes in real time, enabling the system to maintain quasi-zero stiffness characteristics. At the same time, the damping sand hammer assembly 400 can convert minute vibration energy into internal energy, thereby suppressing resonance response and improving the dynamic stability and adaptability of the vibration isolator under complex working conditions.
[0038] Optionally, the main load-bearing mechanism 100 includes an upper load-bearing plate 101, a lower load-bearing plate 102, a central support rod 103, and a central main spring 104.
[0039] Both the upper bearing plate 101 and the lower bearing plate 102 have a central threaded hole, and the two ends of the central support rod 103 are threaded to the central threaded hole respectively; the central main spring 104 is sleeved on the outside of the central support rod 103, and its two ends are fixed to the lower surface of the upper bearing plate 101 and the upper surface of the lower bearing plate 102 respectively; the central support rod 103 is a telescopic structure, which can realize the compression and extension adjustment of the axial height.
[0040] In this embodiment, when vibration occurs, the upper bearing plate 101 is forced to undergo a slight displacement, and the central support rod 103 extends and retracts synchronously, driving the central main spring 104 and the four sets of auxiliary spring units 204 to compress and rebound in coordination. The umbrella-shaped layout makes the load evenly distributed on each auxiliary spring unit 204, thereby improving the overall stiffness matching accuracy of the system and reducing the risk of local stress concentration.
[0041] It should be noted that the upper bearing plate 101 and the lower bearing plate 102 are made of high-strength aluminum alloy, and the flatness tolerance is strictly controlled to <0.05mm. The central support rod 103 is made of stainless steel threaded rod with a straightness tolerance of <0.02mm and a thread accuracy of 6H grade. Both ends are adapted to the central threaded holes of the upper and lower bearing plates to realize axial expansion and contraction adjustment. The central main spring 104 is made of 60Si2MnA spring steel to provide stable positive stiffness for the system.
[0042] Optionally, the preload adjustment mechanism 300 includes four sets of guide rails evenly fixed around the circumference of the lower support plate 102. Each set of guide rails has a slider 304 slidably mounted on it. A column 302 is vertically mounted on the slider 304. The upper end of the column 302 passes through the circular hole on the slip ring 303 and slides with it. The slip ring 303 has a hinge seat arranged circumferentially. The hinge seat is connected to the lower end of the secondary spring unit 200. The upper end of the secondary spring unit 200 is hinged to the annular hinge seat 301. The annular hinge seat 301 is fixed to the end of the central support rod 103 near the upper support plate 101 and is tightly fitted to the lower surface of the upper support plate 101.
[0043] In this embodiment, when the upper bearing plate 101 is subjected to vibration and pressure, it simultaneously causes the central support rod 103 to be axially compressed, which drives the annular hinge seat 301 to move downward, forcing the four sets of secondary spring units 200 to tilt and compress synchronously around the umbrella-shaped apex, thereby forming a negative stiffness response.
[0044] Optionally, the slip ring 303 is a replaceable structure. Different sizes of slip ring 303 can be replaced according to the vibration isolation requirements to change the adjustment range of the relative horizontal angle between the secondary spring unit 200 and the lower bearing plate 102.
[0045] In this embodiment, when the system stiffness characteristics need to be adjusted, the diameter of the slip ring 303 is changed and the radial position of the slider 304 on the guide rail is adjusted simultaneously. This causes the slider 304 to drive the column 302 to move radially, so that the radial constraint reference surface formed by the column 302 conforms to the geometric requirements of the slip ring 303. After this adjustment, the circular hole on the slip ring 303 is aligned with the upper end of the column 302 and inserted and slidably fitted, thus completing the installation and positioning of the slip ring 303. At this time, the initial tilt angle of the secondary spring unit 200 changes accordingly, and the quasi-zero stiffness point of the system also shifts accordingly. This geometric adjustability at the structural level allows the vibration isolator to no longer rely on the intrinsic properties of the material to adapt to the working conditions, but instead achieves the active definition of low-frequency vibration response—stiffness—through the rational reconstruction of the spatial configuration, thus becoming a programmable physical quantity.
[0046] It should be noted that both the annular hinge seat 301 and the slip ring 303 are made of aluminum alloy and are precision cast in one piece. The column 302 is made of stainless steel round rod with a mirror-polished surface to reduce the coefficient of sliding friction with the slip ring 303. The slider 304 uses a high-precision linear guide slider with a sliding positioning accuracy of 0.01mm, ensuring the repeatability and stability of the radial displacement of the column 302, thereby adjusting the horizontal position of the slip ring 303 and driving the auxiliary spring unit 200 to adjust the angle between itself and the horizontal plane according to actual needs.
[0047] Optionally, the secondary spring unit 200 includes a hinge joint 201, a secondary spring connecting piece 202, a secondary spring support rod 203, a secondary spring 204, and an adjusting nut 205;
[0048] There are two hinge joints 201, which are fixedly installed at the upper and lower ends of the auxiliary spring support rod 203 respectively. Both hinge joints 201 are hinged to the annular hinge seat 301 and the hinge seat of the slip ring 303 respectively through cylindrical pins and snap rings. There are two auxiliary spring connecting pieces 202, which are placed at both ends of the auxiliary spring support rod 203 respectively. The auxiliary spring 204 is sleeved on the outside of the auxiliary spring support rod 203, and its two ends abut against the two auxiliary spring connecting pieces 202 respectively.
[0049] The secondary spring support rod 203 is a telescopic structure, which works with the central support rod 103 to adjust the relative horizontal angle between it and the lower bearing plate 102; the adjusting nut 205 is threadedly connected to the lower end of the secondary spring support rod 203, and is used to change the relative position of the secondary spring connecting piece 202 on the secondary spring support rod 203.
[0050] In this embodiment, the screw-in depth of the adjusting nut 205 directly determines the initial preload of the secondary spring 204, enabling the system to better match the static loads of different vibration sources. The deeper the screw-in, the greater the preload and the higher the system stiffness; conversely, the stiffness decreases.
[0051] Four sets of secondary spring units are arranged symmetrically at 90° circumferential angles, forming an umbrella-shaped negative stiffness frame. The changes in their tilt angles and the adjustment of the preload create a dual-degree-of-freedom synergistic control mechanism. Among them, secondary spring 204 is made of 50CrVA spring steel, which generates controllable negative stiffness through geometric nonlinearity. At the same time, the positive and negative stiffnesses of the central main spring 104 and secondary spring 204 are superimposed to accurately achieve the near-zero stiffness characteristics of the system, laying the structural foundation for low-frequency vibration isolation.
[0052] Furthermore, all spring components undergo blanking, rolling, quenching, medium-temperature tempering, and high-pressure treatment to effectively eliminate residual stress, ensure stiffness stability and fatigue resistance, and enable the spring fatigue life to consistently exceed 10 years. 7 Secondly, it ensures the reliability of the vibration isolator during long-term operation.
[0053] Optionally, the damping hammer assembly 400 includes a damping hammer cover 401 and a damping hammer cylinder 402. The damping hammer cylinder 402 is a cylindrical cavity with an open top, which is filled with a damping mixture. The damping hammer cover 401 covers and seals the upper opening of the damping hammer cylinder 402. The damping hammer cylinder 402 is detached and fixed to the lower side of the upper support plate 101 by screws.
[0054] The damping mixture filling the cylindrical cavity of the 402 damping sand hammer cylinder is, by mass percentage, 70%–80% quartz sand, 10%–20% cast iron particles, and 5%–10% damping powder.
[0055] In this embodiment, the damping hammer cylinder 402 is made of stainless steel to prevent corrosion. Its interior is filled with 75% quartz sand, 15% cast iron particles, and 10% nitrile rubber damping powder by weight percentage. The quartz sand is 80 mesh, the cast iron particles are spherical particles with a diameter of 2-3 mm, and the nitrile rubber damping powder is 200 mesh. The mixture forms a multi-layered damping energy dissipation structure of "rigid impact + viscous damping," significantly improving the vibration attenuation capability of the vibration isolator. The damping hammer cover is a rubber sealing cap that seals with the upper opening of the damping hammer cylinder 402 to prevent internal material leakage. The damping hammer assembly 400 is detachably fixed to the lower side of the upper bearing plate 101 using hexagonal screws for easy disassembly and material replacement.
[0056] Optionally, the natural frequency of the vibration isolator can be adjusted within the range of 0.8Hz to 1.2Hz, with a transmission rate of less than 0.05 for 10Hz vibration and less than 0.01 for 50Hz vibration.
[0057] In this embodiment, the natural frequency can be precisely adjusted within the range of 0.8 to 1.2 Hz, providing excellent low-frequency vibration isolation. Simultaneously, relying on the synergistic effect of a main and four auxiliary umbrella-shaped quasi-zero stiffness structure and multiple damping energy dissipation mechanisms, it can achieve efficient isolation of mid-to-high frequency vibrations. The transmissibility of 10 Hz vibration can be controlled below 0.05, and the transmissibility of 50 Hz vibration can be controlled below 0.01. This effectively covers the vibration isolation frequency range required by high-end equipment such as precision instruments and optical platforms, fully meeting the stringent requirements of various precision equipment for micro-vibration control and providing stable vibration isolation assurance for the high-precision operation of the equipment.
[0058] A vibration isolation system includes at least three quasi-zero stiffness isolators, which are evenly arranged at the bottom of the equipment to be isolated.
[0059] In practice, the installation base surface is first leveled to ensure a flatness of <0.5mm / m, preventing unevenness from causing uneven loading of the vibration isolators and affecting the vibration isolation effect. Then, based on the bottom layout of the equipment to be isolated, at least three vibration isolators are arranged symmetrically on the base surface. The lower bearing plate of the vibration isolator is fixed to the base with bolts, and the installation level of the vibration isolator is adjusted to <0.1mm / m. The equipment to be isolated is then placed and fixed onto the surface of the upper bearing plate of the vibration isolator, ensuring even weight distribution. After installation, based on the actual weight of the equipment, the axial height of the central support rod and the preload of the secondary spring are adjusted using the preload adjustment mechanism to adjust the natural frequency of the vibration isolator to the target value. If the characteristics of the vibration source change subsequently, the damping mixture can be replenished or replaced through the filling port of the damping sand hammer cylinder to adjust the damping ratio and adapt to the vibration isolation requirements of different frequency bands.
[0060] All components of this vibration isolator adopt a modular design, which can be disassembled and assembled, making it easy to process, install and maintain. At the same time, by simplifying the structural design, selecting conventional high-quality raw materials and adopting standardized manufacturing processes, the manufacturing cost is reduced by 40% compared with existing quasi-zero stiffness vibration isolators of the same specifications. Furthermore, the overall structural design is reasonable, the components are matched with high precision, there are no easily damaged or consumable parts, and the overall service life is >10 years, which combines economy and practicality.
[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A preload-adjustable quasi-zero stiffness vibration isolator, characterized in that: It includes a main load-bearing mechanism (100), four sets of auxiliary spring units (200), a preload adjustment mechanism (300), and four sets of damping sand hammer assemblies (400). The main bearing mechanism (100) is composed of a central support rod (103) connecting the upper bearing plate (101) and the lower bearing plate (102), and is used to bear and transmit vertical loads; the bottom of the preload adjustment mechanism (300) is set on the lower bearing plate (102), and the top is in close contact with the upper bearing plate (101) to form a stable axial constraint; four sets of the auxiliary spring units (200) are arranged symmetrically in a 90° circumferential direction around the preload adjustment mechanism (300) to form an umbrella-shaped support system; The four sets of damping sand hammer assemblies (400) are symmetrically arranged on the lower surface of the upper bearing plate (101).
2. The preload-adjustable quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The main bearing mechanism (100) includes an upper bearing plate (101), a lower bearing plate (102), a central support rod (103), and a central main spring (104). Both the upper support plate (101) and the lower support plate (102) have a central threaded hole in their center. The two ends of the central support rod (103) are threaded to the central threaded hole respectively. The central main spring (104) is sleeved on the outside of the central support rod (103), and its two ends are fixed to the lower surface of the upper support plate (101) and the upper surface of the lower support plate (102) respectively. The central support rod (103) is a telescopic structure, which can realize the compression and extension adjustment of the axial height.
3. The preload-adjustable quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The preload adjustment mechanism (300) includes four sets of guide rails evenly fixed around the circumference of the lower support plate (102). Each set of guide rails has a slider (304) slidably mounted on it. A column (302) is vertically mounted on the slider (304). The upper end of the column (302) passes through the circular hole on the slip ring (303) and slides with it. The slip ring (303) has a hinge seat arranged around its circumference. The hinge seat is connected to the lower end of the secondary spring unit (200). The upper end of the secondary spring unit (200) is hinged to the annular hinge seat (301). The annular hinge seat (301) is fixed to the end of the central support rod (103) near the upper support plate (101) and is tightly fitted to the lower surface of the upper support plate (101).
4. A preload-adjustable quasi-zero stiffness vibration isolator according to claim 3, characterized in that: The slip ring (303) is a replaceable structure. Different sizes of slip rings (303) can be replaced according to the vibration isolation requirements to change the relative horizontal angle adjustment range between the secondary spring unit (200) and the lower bearing plate (102).
5. A preload-adjustable quasi-zero stiffness vibration isolator according to claim 3, characterized in that: The secondary spring unit (200) includes a hinge joint (201), a secondary spring connecting piece (202), a secondary spring support rod (203), a secondary spring (204), and an adjusting nut (205). There are two hinge joints (201), which are fixedly installed at the upper and lower ends of the auxiliary spring support rod (203). The two hinge joints (201) are respectively hinged to the hinge seat of the annular hinge seat (301) and the hinge seat of the slip ring (303) by cylindrical pins and snap rings. There are two auxiliary spring connecting pieces (202), which are respectively placed at both ends of the auxiliary spring support rod (203). The auxiliary spring (204) is sleeved on the outside of the auxiliary spring support rod (203), and its two ends abut against the two auxiliary spring connecting pieces (202). The secondary spring support rod (203) is a telescopic structure, which works with the central support rod (103) to adjust the relative horizontal angle between it and the lower bearing plate (102); the adjusting nut (205) is connected to the lower end of the secondary spring support rod (203) by a thread, and is used to change the relative position of the secondary spring connecting piece (202) on the secondary spring support rod (203).
6. A preload-adjustable quasi-zero stiffness vibration isolator according to claim 1, characterized in that: The damping hammer assembly (400) includes a damping hammer cover (401) and a damping hammer cylinder (402). The damping hammer cylinder (402) is a cylindrical cavity with an open top, which is filled with a damping mixture. The damping hammer cover (401) covers and seals the upper opening of the damping hammer cylinder (402). The damping hammer cylinder (402) is fixed to the lower side of the upper support plate (101) by screws.
7. A preload-adjustable quasi-zero stiffness vibration isolator according to claim 6, characterized in that: The damping mixture filling the cylindrical cavity of the damping sand hammer cylinder (402) is, by mass percentage, 70%–80% quartz sand, 10%–20% cast iron particles, and 5%–10% damping powder.
8. A preload-adjustable quasi-zero stiffness vibration isolator according to any one of claims 1-7, characterized in that: The natural frequency of the vibration isolator can be adjusted within the range of 0.8Hz to 1.2Hz, and the transmission rate for 10Hz vibration is less than 0.05, while the transmission rate for 50Hz vibration is less than 0.
01.
9. A vibration isolation system, characterized in that, It includes at least three preload-adjustable quasi-zero stiffness vibration isolators as described in any one of claims 1-8, the quasi-zero stiffness vibration isolators being evenly arranged at the bottom of the vibration-isolated equipment.