A modular ultra-low frequency vibration isolation device with load-adaptive characteristics

Abstract

The present invention discloses a modular ultra-low frequency vibration isolation device with load adaptive characteristics, which belongs to the field of vibration absorbers. It adopts a highly modular structural design, and the vibration isolation modules are installed at equal axial intervals between the load support platform and the base. The vibration isolation modules are connected to each other through a standardized interface set in the center of the base. A vertical preload adjustment device and a horizontal preload adjustment device are designed in each vibration isolation unit. By adjusting the vertical preload device to dynamically adjust the effective load of the entire vibration isolation system, the vibration isolation device can provide the best vibration isolation effect under different load conditions; by adjusting the preload distance of the horizontal preload device, the vibration isolation device can present a constant zero stiffness feature at any position. As a result, the entire vibration isolation device presents different stiffness properties such as high static and low dynamic stiffness, quasi-zero stiffness, and constant zero stiffness. It can adapt to a wider range of working environments and vibration conditions and is simple to operate, providing users with great convenience and flexibility.

Description

Technical Field

[0001] The invention belongs to the field of vibration absorbers, and in particular relates to a modular ultra-low frequency vibration isolation device with load adaptive characteristics. Background Art

[0002] With the rapid development of industry and technology, the demand for ultra-low frequency vibration isolation is increasing, especially in high-end applications such as precision instruments, aerospace, marine engineering, and high-speed railways. Traditional vibration isolation devices often face challenges such as poor low-frequency vibration isolation, complex structures, high costs, and difficulty adapting to different load conditions.

[0003] In recent years, quasi-zero stiffness vibration isolation technology has become a research hotspot due to its excellent vibration isolation performance. Quasi-zero stiffness vibration isolation devices can provide high load-bearing capacity in static conditions and exhibit low stiffness characteristics in dynamic conditions, thereby effectively widening the vibration isolation frequency band and improving the low-frequency vibration isolation effect. However, existing quasi-zero stiffness vibration isolation devices are only effective for specific vibration isolation loads corresponding to the static equilibrium position and cannot achieve adaptive adjustment of the load. Once the load mass deviates from the static equilibrium position, it is difficult for the quasi-zero stiffness vibration isolation system to maintain optimal vibration isolation performance, resulting in a decline in system performance or even failure. In order to adapt to the working conditions of different loads, the vibration isolation device needs to be replaced to achieve the expected vibration isolation effect, which causes great inconvenience in actual engineering applications. Summary of the Invention

[0004] To address the above problems, the present invention proposes a modular ultra-low frequency vibration isolation device with load-adaptive characteristics, which has the adjustability of different stiffness properties such as high static and low dynamic stiffness, quasi-zero stiffness, and constant zero stiffness.

[0005] The modular ultra-low frequency vibration isolation device with load self-adaptation characteristics of the present invention comprises a supporting base, an outer shell, a connecting inner seat, a load supporting platform and a plurality of vibration isolation units.

[0006] The top surface of the support base is coaxially mounted with a connecting inner seat. The vibration isolation units are circumferentially evenly distributed around the outer periphery of the connecting inner seat, fixed to the support base, and respectively connected to the connecting interfaces evenly distributed around the inner seat.

[0007] The vibration isolation unit consists of a mounting base, a horizontal guide rod, a vertical guide rod, a horizontal spring, a vertical spring, a horizontal slip ring, a vertical slip ring, a horizontal preload device, a vertical preload device, a first connecting rod, a second connecting rod and a locking bolt.

[0008] The mounting base is a T-shaped structure consisting of a bottom plate and a longitudinal plate, secured to the top surface of the support base via the bottom plate. A horizontal guide rod is positioned parallel to the top surface of the support base, with its distal end fixedly connected to the longitudinal plate. The front end of the horizontal guide rod is fixedly connected to the connection interface on the inner connection base. A vertical guide rod is positioned perpendicular to the support base, with its bottom end fixed to the support base and its top end connected to the load support platform.

[0009] The above-mentioned horizontal guide rod is sequentially covered with a horizontal slip ring, a horizontal spring and a horizontal preload device from back to front; wherein, the horizontal preload device includes a horizontal preload body and a horizontal locking bolt; the horizontal preload body is covered on the horizontal guide rod and is locked and fixed by the horizontal locking bolt to realize the adjustment of the horizontal spring preload force.

[0010] The vertical guide rod is sequentially covered with a vertical slip ring, a vertical spring and a vertical preload device from top to bottom; wherein, the vertical preload device includes a vertical preload body and a vertical locking bolt; the vertical preload body is covered on the vertical guide rod and is locked and fixed by the vertical locking bolt to realize the adjustment of the vertical spring preload force.

[0011] Furthermore, the horizontal slip ring and the vertical slip ring are connected via a first connecting rod and a second connecting rod that are symmetrically arranged on the left and right.

[0012] The load supporting platform is sleeved with the top ends of the longitudinal rods of the vibration isolation units which are evenly distributed in the circumferential direction through columnar joints which are evenly distributed in the circumferential direction on the bottom surface.

[0013] The modular ultra-low frequency vibration isolation device of the present invention has load-adaptive characteristics. External excitation is directly transmitted to the vibration isolation unit of the present invention through the support base. The vibration signal is attenuated by the circumferential vibration isolation unit and then transmitted to the vibration isolation load set on the load support platform. Moreover, through the adjustment and coordination of the horizontal preload device and the vertical preload device, the entire vibration isolation device can exhibit different stiffness properties such as high static and low dynamic stiffness, quasi-zero stiffness, and constant zero stiffness.

[0014] The advantages of the present invention are:

[0015] 1. Adaptive Load Adjustment: The device of this invention can adaptively adjust the load-bearing capacity of the designed vibration isolation device according to the mass of the isolated object to be protected. Specifically, by adjusting the vertical preload device, the effective load of the entire vibration isolation system is dynamically adjusted, enabling the vibration isolation device to provide optimal vibration isolation under different load conditions. This adaptive capability not only improves the adaptability and stability of the device, but also significantly enhances its reliability and durability in complex working conditions, providing strong support for applications in precision instruments, high-end equipment, and special environments.

[0016] 2. Modular Expansion: A key feature of the device is its highly modular structure. Each isolation module has its own independent isolation function, and modules are interconnected via standardized interfaces, allowing users to easily expand or reduce the device based on actual needs. This modular design not only simplifies installation and maintenance, reducing costs, but also significantly increases the device's flexibility and scalability, meeting the personalized needs of diverse scenarios and projects of varying sizes, facilitating large-scale applications.

[0017] 3. Ultra-low frequency vibration isolation performance: To address the poor performance of traditional vibration isolation devices in ultra-low frequency vibration environments, this invention utilizes advanced ultra-low frequency vibration isolation technology. By adjusting the preload distance of the horizontal preload device, the vibration isolation device can exhibit a constant zero stiffness characteristic at any position, enabling it to maintain excellent vibration isolation performance even in extremely low frequency vibration environments.

[0018] 4. Adjustable stiffness properties: The device of the present invention can make the entire vibration isolation device present different stiffness properties such as high static and low dynamic stiffness, quasi-zero stiffness, and constant zero stiffness through the adjustment and coordination of the horizontal preload device and the vertical preload device. This adjustability enables the device to adapt to a wider range of working environments and vibration conditions. Whether high stiffness is required to resist external impact or low stiffness is required to achieve a more refined vibration isolation effect, it can be achieved through simple operation, providing users with great convenience and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of the modular ultra-low frequency vibration isolation device of the present invention;

[0020] Figure 2 This is a schematic diagram of the overall internal structure of the modular ultra-low frequency vibration isolation device of the present invention;

[0021] Figure 3 Schematic diagram of the structure of the vibration isolation unit in the modular ultra-low frequency vibration isolation device of the present invention;

[0022] Figure 4 This is a mechanical principle diagram of the vibration isolation unit in the modular ultra-low frequency vibration isolation device of the present invention when the horizontal and vertical preload devices are not activated;

[0023] Figure 5 This is a mechanical principle diagram of the vibration isolation unit after the horizontal and vertical preload devices in the modular ultra-low frequency vibration isolation device of the present invention are activated;

[0024] Figure 6 Schematic diagram of load adjustment of the vibration isolation unit in the modular ultra-low frequency vibration isolation device of the present invention;

[0025] Figure 7 This is a comparison chart of the vibration isolation performance corresponding to different stiffness properties of the modular ultra-low frequency vibration isolation device of the present invention.

[0026] In the picture:

[0027] 1-Support base 2-Outer shell 3-Connecting inner seat

[0028] 4-Load support platform 5-Vibration isolation unit 401-Column joint

[0029] 501-mounting seat 501a-bottom plate 501b-vertical plate

[0030] 503-vertical guide rod 504-horizontal spring 505-vertical spring

[0031] 506-Horizontal slip ring 507-Vertical slip ring 508-Horizontal preload device

[0032] 508a-Horizontal preload body 508b-Horizontal locking bolt 509-Vertical preload device

[0033] 509a - vertical preload body 509b - vertical locking bolt 510 - first connecting rod

[0034] 511-Second connecting rod 512-Locking bolt DETAILED DESCRIPTION

[0035] The modular ultra-low frequency vibration isolation device with load adaptive characteristics of the present invention mainly includes a support base 1, a shell 2, a connecting inner seat 3, a load supporting platform 4 and a plurality of vibration isolation units 5, such as Figure 1 、 Figure 2 shown.

[0036] The support base 1 is a circular plate structure that serves as a support for the other components. A cylindrical inner connection seat 3 is coaxially mounted at the center of the top surface of the support base 1. The bottom end of the inner connection seat 3 is fixedly connected to the upper surface of the support base 1. The inner connection seat 3 has connection ports distributed evenly around the circumference, equal in number to the number of isolation units 5, for connecting to the isolation units 5.

[0037] The vibration isolation unit 5 is the core component of the present invention. A plurality of vibration isolation units are evenly distributed around the outer periphery of the connecting inner seat 3 at equal angular intervals in the circumferential direction and are connected to the support base 1 and the connecting inner seat 3. Figure 3 As shown, the vibration isolation unit 5 consists of a mounting base 501, a horizontal guide rod 502, a vertical guide rod 503, a horizontal spring 504, a vertical spring 505, a horizontal slip ring 506, a vertical slip ring 507, a horizontal preload device 508, a vertical preload device 509, a first connecting rod 510, a second connecting rod 511 and a locking bolt 512.

[0038] The mounting base 501 is a T-shaped structure consisting of a base plate 501a and a vertical plate 501b perpendicular to the base plate 501a. The bottom surface of the base plate 501a is attached to and fixed to the upper surface of the support base 1. After the base plate 501a is fixed, a perpendicular line passing through the longitudinal midline of the vertical plate 501b must intersect the axis connecting the inner base 3.

[0039] Horizontal guide rod 502, located at the top of the vertical plate, is a D-shaped cross-section connecting rod. Its flat side is parallel to the upper surface of support base 1, and its axis is perpendicular to vertical plate 501b and passes through the longitudinal centerline of vertical plate 501b. The distal end of horizontal guide rod 502 engages with a D-shaped hole in vertical plate 501b and is secured by a circumferential shoulder. The distal end of horizontal guide rod 502 engages with a D-shaped connection port and is secured by a circumferential shoulder.

[0040] The vertical guide rod 503 is located outside the longitudinal plate 501b and has a D-shaped cross-section. Its flat side is parallel to the longitudinal plate 501b, with its axis perpendicular to the upper surface of the support base 1 and intersecting with the axis of the horizontal guide rod 502. The bottom end of the vertical guide rod 503 fits through corresponding holes in the base plate 501a and the support base 1, and is secured by a circumferential shoulder. The top end of the vertical guide rod 503 is connected to the load-supporting platform 4.

[0041] The horizontal guide rod 502 is provided with a horizontal slip ring 506, a horizontal spring 504 and a horizontal preload device 508 in sequence from back to front. The horizontal slip ring 506 is sleeved with the horizontal guide rod 502 through a D-shaped hole provided thereon, limiting the axial rotation of the horizontal slip ring 506.

[0042] The horizontal preload device 508 includes a rectangular block-shaped horizontal preload body 508a and a horizontal locking bolt 508b. The body 508a is fitted with the horizontal guide rod 502 through a D-shaped hole provided thereon, and its top surface is parallel to the upper surface of the support base 1. A threaded hole is provided on the top surface of the horizontal preload body 508a, which communicates with the D-shaped hole; a horizontal locking bolt 508b is fitted in the threaded hole. Thus, by loosening the horizontal locking bolt 508b, the position of the horizontal preload body 508a can be adjusted along the horizontal guide rod 502, thereby achieving preload adjustment of the horizontal spring 504. After the preload adjustment is completed, the horizontal preload device 508 is secured to the horizontal guide rod 502 by tightening the horizontal locking bolt, so that it does not loosen during vibration and affect the vibration isolation effect; at the same time, a spring washer is provided on the horizontal locking bolt 508b to prevent the horizontal locking bolt 508b from loosening.

[0043] The vertical guide rod 503 is sleeved with a vertical slip ring 507, a vertical spring 505 and a vertical preload device 509 from top to bottom. The vertical slip ring 507 is sleeved with the vertical guide rod 503 through a D-shaped hole provided thereon, which limits the axial rotation of the vertical slip ring 507.

[0044] The vertical preload device 509 comprises a rectangular block-shaped vertical preload body 509a and a vertical locking bolt 509b. The vertical preload body 509a engages with the vertical guide rod 503 through a D-shaped hole, with its outer surface parallel to the longitudinal plate 501b. A threaded hole is also provided on the outer sidewall of the vertical preload body 509a, connecting to the D-shaped hole. The vertical locking bolt 509b is threadedly mounted within the threaded hole. By loosening the vertical locking bolt 509b, the position of the vertical preload body 509a along the vertical guide rod 503 can be adjusted, thereby adjusting the preload force of the vertical spring 505. After the preload force is adjusted, the vertical preload device 509 is firmly attached to the vertical guide rod 503 by tightening the vertical locking bolt 509b so that it does not loosen during vibration and affect the vibration isolation effect; at the same time, a spring washer is placed on the vertical locking bolt 509b to prevent the vertical locking bolt 509b from loosening.

[0045] Furthermore, the horizontal slip ring 506 and the vertical slip ring 507 are connected by a first connecting rod 510 and a second connecting rod 511, which are arranged symmetrically on both sides. The front ends of the two connecting rods are connected to the corresponding positions in the middle of the left and right sides of the horizontal slip ring to form a revolute pair; the rear ends are connected to the corresponding positions in the middle of the left and right sides of the vertical slip ring 507 to form a revolute pair.

[0046] The load support platform 4 is directly connected to each vibration isolation unit 5, and its top surface can be directly used to carry the vibration isolation load that needs to be protected. The load support platform 4 is a circular plate-shaped platform, which is arranged parallel to the support base 1. The bottom surface is designed with columnar joints 401 at equal angles in the circumference, which is equal to the number of vibration isolation units 5; the axis of the joint 401 is perpendicular to the lower surface of the load support platform 4, and a D-shaped hole is opened in the longitudinal direction. Through the D-shaped holes on each joint 401 on the support platform 4, it is respectively plugged with the top of the vertical guide rod 503 in each vibration isolation unit 5, and the pre-tightening force of the vertical spring 505 is contacted with the vertical slip ring 507 to limit the position; and there is a certain distance D between the top of the vertical guide rod 503 and the bottom surface of the joint groove, which is the limit displacement of the load support platform 4 moving downward.

[0047] The housing 2 protects the vibration isolation unit 5 from the external environment and also provides aesthetic appeal. The housing 2 is a cylindrical structure, coaxially arranged with the support base 1, and circumferentially extends over the outside of the vibration isolation unit 5. Through holes are defined on the bottom circumference, mate with through holes on the outer edge of the support base 1. Screws are inserted through the through holes to secure the housing to the support base 1. The inner diameter of the housing 2 is larger than the outer diameter of the load-supporting platform 4, ensuring that it does not impede downward movement.

[0048] During operation of the vibration isolation unit 5 of the above structure, the horizontal guide rod 502 always remains horizontal, the front end of the horizontal spring 504 always contacts the horizontal preload device 508, and the rear end always contacts the horizontal slip ring 506, allowing the horizontal slip ring 506 to move freely on the horizontal guide rod 502. Similarly, the vertical guide rod 503 always remains vertical, the bottom end of the vertical spring 505 always contacts the vertical preload device 509, and the other end always contacts the vertical slip ring 507, allowing the vertical slip ring 507 to move freely on the vertical guide rod 503. The D-shaped cross-section design of the horizontal guide rod 502 and the vertical guide rod 503 allows the horizontal preload device 508 and the vertical preload device 509 to be securely fixed to the guide rods; the coordination of the vibration isolation unit 5 during movement is ensured by the first connecting rod 510 and the second connecting rod 511, preventing physical collisions between the components of the vibration isolation unit 5 during movement, while ensuring the stability of the structure.

[0049] Through the modular ultra-low frequency vibration isolation device with load-adaptive characteristics of the present invention, the external excitation is directly transmitted to the vibration isolation unit 5 of the present invention through the support base 1, and the vibration signal is attenuated by the vibration isolation unit 5 in the circumferential direction and then transmitted to the vibration isolation load set on the load support platform 4. At the same time, the present invention constructs a highly flexible and adaptable vibration isolation device with a highly modular structure. Each module has an independent vibration isolation function, and the modules are interconnected through standardized interfaces; therefore, the device can be easily expanded or reduced according to actual needs, which not only enhances the load adaptability of the entire vibration isolation device, enabling it to cope with a wide range of changes from lightweight to heavy loads, but also improves the redundancy and reliability of the vibration isolation device. In addition, the modular design also facilitates subsequent maintenance and upgrades. By adding or replacing vibration isolation units to meet different load requirements, the service life of the system is extended and long-term operating costs are reduced.

[0050] The working principle of the modular ultra-low frequency vibration isolation device with load adaptive characteristics of the present invention is as follows:

[0051] The mechanical model of the vibration isolation unit 5 is as follows: Figure 4 、 Figure 5 As shown. The stiffness coefficient of the horizontal spring 504 is k1, the stiffness coefficient of the vertical spring 505 is k2, and the length of the first and second connecting rods is L. When the horizontal and vertical preload devices are effective, assuming that the adjustment distance of the horizontal preload device 508 is δ1, the adjustment distance of the vertical preload device 509 is δ2, the distance between the top hinge point of the first and second connecting rods and the horizontal guide rod 502 in the initial state is h, the displacement of the isolation load is x, and the output force of the vibration isolation unit 5 in the vertical direction is F. The force-displacement relationship of the vibration isolation unit 5 can be calculated as:

[0052]

[0053] Since the isolated load of a certain mass is placed on the load support platform 4, the load support platform 4 will move downward and eventually reach an equilibrium position. During the design process, this equilibrium position is designed to be at the same height as the horizontal guide rod 502, which is the static equilibrium position. Because the response of the system to external excitation at the static equilibrium position is usually considered under vibration, the vertical displacement of the isolated load is defined as the equilibrium displacement u, with the vertical position of the horizontal guide rod 502 as the base point, that is:

[0054] u=xh (2)

[0055] The output force can be converted into:

[0056]

[0057] After Taylor series expansion, the above formula can be equivalently transformed into the following form:

[0058]

[0059] When the horizontal preload device 508 and the vertical preload device 509 are not activated, the horizontal spring and the vertical spring are both in a free state. The above formula can be further rewritten as:

[0060]

[0061] It can be seen that at this time, the vibration isolation unit 5 is a typical high-static and low-dynamic vibration isolation system with a linear stiffness and a cubic nonlinear stiffness. The high-static and low-dynamic system is converted into a quasi-zero stiffness vibration isolation system if and only if the following relationship is satisfied:

[0062]

[0063] At this time, the effective bearing capacity of the vibration isolation unit 5 is k2h.

[0064] It can be seen from formula (4) that when the horizontal preload device 508 and the vertical preload device 509 are adjusted, the output force F of the vibration isolation unit 5 can be adjusted, and the stiffness characteristics of the vibration isolation unit 5 can be adjusted. Figure 6 As shown, when δ1 and δ2 are adjusted, the output characteristics of the vibration isolation unit 5 can be adjusted.

[0065] Therefore, when the vertical preload device 509 is adjusted, that is, the value of δ2 is changed, the bearing capacity of the vibration isolation device of the present invention can be adjusted instead of the original k2h. The bearing capacity of the vibration isolation device after adjustment is k2(h+δ2).

[0066] When the horizontal preload device 508 is adjusted, that is, the value of δ1 is changed, the vibration isolation unit exhibits a quasi-zero stiffness characteristic when the following conditions are met:

[0067]

[0068] As can be seen from formula (6), when both horizontal preload device 508 and vertical preload device 509 are deactivated, vibration isolation unit 5 must achieve a quasi-zero stiffness characteristic, placing strict requirements on the stiffness coefficients of the two springs. However, when horizontal preload device 508 is activated, vibration isolation unit 5 essentially has an additional parameter that can be adaptively adjusted. By adjusting δ1, vibration isolation unit 5 can always exhibit a quasi-zero stiffness characteristic, and the stiffness coefficients of the two springs can be freely selected.

[0069] In addition, when the system meets the following conditions, the vibration isolation unit 5 can present a constant zero stiffness characteristic:

[0070]

[0071] The output force of the isolation unit is always:

[0072] F=k2(h+δ2) (9)

[0073] like Figure 6 The figure shows a schematic diagram of load adjustment of the vibration isolation unit 5. Combined with formula (9), when δ2 is adjusted, its effective bearing capacity can be adjusted and is no longer the original k2h.

[0074] This means that the vibration isolation unit 5 can always maintain a zero stiffness characteristic, and its effective load capacity can be adaptively adjusted by adjusting the vertical preload device. The dynamic stiffness of the vibration isolation unit is always 0, which can present the best vibration isolation effect.

[0075] like Figure 7 The vibration transmissibility curves corresponding to different stiffness properties are shown. The vibration transmissibility can intuitively describe the vibration isolation performance of the vibration isolation device. When the vibration transmissibility is less than 0, it indicates that the vibration isolation device has the effect of vibration suppression, and the smaller the value, the better the vibration isolation effect. It can be seen that when the stiffness characteristics of the vibration isolation device of the present invention are adjusted by the horizontal preload device, the system can be transformed from a high static and low dynamic stiffness system to a quasi-zero stiffness system, and when formula (8) is satisfied, the system behaves as a constant zero stiffness system. In the quasi-zero stiffness system and the constant zero stiffness system, the vibration transmissibility is always negative, indicating that there is a vibration isolation effect in the entire frequency band, ultra-low frequency vibration isolation can be achieved, and the constant zero stiffness system has a better vibration isolation effect.

Claims

1. A modular ultra-low frequency vibration isolation device with load-adaptive characteristics, characterized by: It includes a supporting base, an outer shell, a connecting inner seat, a load supporting platform and several vibration isolation units; The top surface of the support base is coaxially mounted with a connecting inner seat; The vibration isolation units are uniformly distributed around the periphery of the connecting inner seat, fixed on the support base, and respectively connected to the connecting interfaces uniformly distributed around the connecting inner seat; the vibration isolation units are composed of a mounting seat, a horizontal guide rod, a vertical guide rod, a horizontal spring, a vertical spring, a horizontal slip ring, a vertical slip ring, a horizontal preload device, a vertical preload device, a first connecting rod, a second connecting rod and a locking bolt; The mounting base is a T-shaped structure consisting of a bottom plate and a longitudinal plate, which is fixed to the top surface of the support base through the bottom plate; the horizontal guide rod is arranged parallel to the top surface of the support base, and the end is fixedly connected to the longitudinal plate; the front end of the horizontal guide rod is fixedly connected to the connection interface on the inner seat; the vertical guide rod is arranged perpendicular to the support base, the bottom end is fixed to the support base, and the top end is connected to the load support platform; The horizontal guide rod is provided with a horizontal slip ring, a horizontal spring and a horizontal preload device in sequence from back to front. The horizontal preload device includes a horizontal preload body and a horizontal locking bolt. The horizontal preload body is sleeved on the horizontal guide rod and is locked and fixed by the horizontal locking bolt to achieve adjustment of the horizontal spring preload force. The vertical guide rod is provided with a vertical slip ring, a vertical spring and a vertical preload device in sequence from top to bottom; wherein the vertical preload device comprises a vertical preload body and a vertical locking bolt; the vertical preload body is sleeved on the vertical guide rod and is locked and fixed by the vertical locking bolt to achieve vertical spring preload adjustment; Furthermore, the horizontal slip ring and the vertical slip ring are further connected via a first connecting rod and a second connecting rod that are symmetrically arranged on both sides; The load supporting platform is connected to the top end of the longitudinal rod of the vibration isolation unit uniformly distributed in the circumferential direction through the columnar joints uniformly distributed in the circumferential direction on the bottom surface; When the vertical preload device is adjusted, the load-bearing capacity is adjusted to k2 (h + δ2); Wherein, k2 is the stiffness coefficient of the vertical spring; h is the distance between the top hinge point of the first and second connecting rods and the horizontal guide rod in the initial state; δ2 is the adjustment distance of the vertical preload device; When the horizontal preload device is adjusted to meet the following conditions, the vibration isolation unit exhibits quasi-zero stiffness characteristics: Wherein, k1 is the stiffness coefficient of the horizontal spring; L is the length of the first link and the second link; δ1 is the adjustment distance of the horizontal preload device; When the following conditions are met, a constant zero stiffness characteristic is exhibited: The output force of the isolation unit is always: 。 2. A modular ultra-low frequency vibration isolation device with load-adaptive characteristics as claimed in claim 1, characterized in that: It also includes a cylindrical shell; the inner diameter of the shell is larger than the outer diameter of the load support platform, is coaxially arranged with the support platform, is sleeved on the outside of the vibration isolation unit in the circumferential direction, and the bottom is fixed to the support base.

3. The modular ultra-low frequency vibration isolation device with load adaptive characteristics according to claim 1, characterized in that: During assembly, the perpendicular line passing through the longitudinal center line of the longitudinal plate intersects with the axis connecting the inner seat; the axis of the horizontal guide rod is perpendicular to the longitudinal plate and passes through the longitudinal center line of the longitudinal plate; the vertical guide rod is located on the outside of the longitudinal plate, its axis is perpendicular to the upper surface of the support base, and intersects with the axis of the horizontal guide rod.

4. The modular ultra-low frequency vibration isolation device with load adaptive characteristics according to claim 1, characterized in that: The bottom end of the vertical guide rod is fixed after passing through the through holes opened at corresponding positions of the bottom plate and the support base.

5. The modular ultra-low frequency vibration isolation device with load adaptive characteristics according to claim 1, characterized in that: Add or replace vibration isolation units to meet different load requirements.

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