A quasi-zero stiffness vibration isolator

Abstract

This invention relates to the field of precision vibration isolation technology and discloses a quasi-zero stiffness vibration isolator, including a base, a load platform, a first adjustment module, and a second adjustment module. The first adjustment module includes a first plate, several positive stiffness adjustment units, and a drive wheel adjustment structure. The drive wheel adjustment structure is used to synchronously adjust the support height of each positive stiffness adjustment unit. The second adjustment module includes several negative stiffness adjustment units corresponding to the positive stiffness adjustment units. Each negative stiffness adjustment unit adjusts the pre-compression buckling amount of the negative stiffness spring through a radial adjustment mechanism. The positive stiffness provided by the positive stiffness adjustment units and the negative stiffness provided by the negative stiffness adjustment units are connected in parallel, causing the vibration isolator to exhibit quasi-zero stiffness characteristics near the equilibrium position. This invention can improve the support stability and positive / negative stiffness matching accuracy under eccentric loading or different load conditions, and improve the low-frequency vibration isolation effect.

Description

Technical Field

[0001] This invention relates to the field of precision vibration isolation technology, specifically to a quasi-zero stiffness vibration isolator. Background Technology

[0002] With the increasing demands for environmental vibration control in fields such as precision measurement and metrology, advanced manufacturing, and precision machining, the suppression of low-frequency vibrations is becoming increasingly important. Passive vibration isolation devices have advantages such as simple structure and high reliability, and are therefore widely used. In linear vibration isolation systems, reducing the system's natural frequency helps to expand the low-frequency isolation range; connecting a negative stiffness structure in parallel with a positive stiffness structure to create quasi-zero stiffness near the equilibrium position is an effective way to reduce the natural frequency.

[0003] Quasi-zero stiffness vibration isolators typically require adjustment based on load weight and center of gravity position. When the support point arrangement is unstable or the heights of the support points are inconsistent, the load is prone to tilting and is highly sensitive to the placement of the isolated object. On the other hand, a precise match between positive and negative stiffness is required; if only overall adjustment is possible or the adjustment resolution is insufficient, it is difficult to compensate for manufacturing and assembly errors and local force differences caused by load eccentricity, thus making it difficult to maintain a quasi-zero stiffness state near the equilibrium position.

[0004] Therefore, there is a need for a quasi-zero stiffness vibration isolator that provides stable support, can adapt to different loads, and allows for independent and precise adjustment of negative stiffness. Summary of the Invention

[0005] This invention provides a quasi-zero stiffness vibration isolator to solve the problems of insufficient support stability, low load balance and positive and negative stiffness matching adjustment accuracy of existing quasi-zero stiffness vibration isolators under eccentric load or different load conditions, making it difficult to stably obtain a quasi-zero stiffness vibration isolation state.

[0006] This invention provides a quasi-zero stiffness vibration isolator, comprising: a base, a load platform, a first adjustment module, and a second adjustment module; the load platform is used to support the object to be isolated; the first adjustment module is disposed between the load platform and the base, and includes a first plate and a plurality of positive stiffness adjustment units, the upper end of the positive stiffness adjustment unit being connected to the first plate and the lower end of the positive stiffness adjustment unit being connected to the base, the first plate being connected to the load platform, and the positive stiffness adjustment unit being used to provide positive stiffness in the vertical direction to the load platform; the second adjustment module is disposed on the base, and includes a plurality of negative stiffness adjustment units, the negative stiffness adjustment units being correspondingly disposed to the positive stiffness adjustment units, each negative stiffness adjustment unit including a negative stiffness spring and a radial adjustment mechanism, the radial adjustment mechanism being used to adjust the pre-compression buckling amount of the negative stiffness spring in the radial direction, the negative stiffness spring being connected to the first plate and used to provide negative stiffness in the vertical direction; The positive stiffness provided by the positive stiffness adjustment unit is connected in parallel with the negative stiffness provided by the negative stiffness adjustment unit, so that the quasi-zero stiffness vibration isolator exhibits quasi-zero stiffness characteristics near the equilibrium position.

[0007] Beneficial effects: The load borne by the load platform is transmitted to several positive stiffness adjustment units via the first plate. These units collectively provide vertical positive stiffness to the load platform, improving its support stability. Negative stiffness adjustment units are correspondingly arranged to the positive stiffness adjustment units. By adjusting the pre-buckling amount of the negative stiffness springs radially via a radial adjustment mechanism, the negative stiffness characteristics of the springs during compressive buckling can be altered, thus matching the negative stiffness at each support position with the corresponding positive stiffness. Therefore, under conditions of off-center loading, varying load weight, or inconsistent forces at different support positions, the positive and negative stiffness can be adaptively adjusted, allowing the quasi-zero stiffness isolator to achieve a lower equivalent stiffness near the equilibrium position, thereby reducing the system's resonant frequency and improving low-frequency vibration isolation.

[0008] According to some embodiments of the present invention, at least three positive stiffness adjustment units are provided, and the three positive stiffness adjustment units are distributed in a 120° circumferential direction; At least three negative stiffness adjustment units are provided, and the three negative stiffness adjustment units are distributed circumferentially at 120°. The three negative stiffness adjustment units and the three positive stiffness adjustment units are arranged at uniform intervals along the circumferential direction.

[0009] Beneficial effects: The three positive stiffness adjustment units are distributed circumferentially at 120°, forming a three-point support around the load platform. This distributes the load across the three support positions, improving the platform's stability and reducing the sensitivity of the quasi-zero stiffness isolator to the placement of the isolated object. The three negative stiffness adjustment units are also distributed circumferentially at 120° intervals, evenly spaced from the three positive stiffness adjustment units. This ensures a reasonable circumferential distribution of positive and negative stiffness application points, improving the load platform's stress uniformity and providing an adjustment basis for matching positive and negative stiffness at different support positions.

[0010] According to some embodiments of the present invention, the second adjustment module further includes a second plate body disposed on the base base, and a plurality of the negative stiffness adjustment units disposed on the second plate body; The first adjustment module also includes a drive wheel adjustment structure, which is connected to the positive stiffness adjustment unit to synchronously adjust the support height of the three sets of positive stiffness adjustment units.

[0011] Beneficial effects: The second plate provides a common mounting base for several negative stiffness adjustment units, facilitating the determination of their relative positions and improving the overall structural stability of the second adjustment module. The drive wheel adjustment structure is connected to the three positive stiffness adjustment units, allowing for synchronous adjustment of their support heights. This reduces height deviations caused by individual adjustments, facilitating the adjustment of the load platform's support status based on the weight of the isolated object and maintaining the load platform's balance.

[0012] According to some embodiments of the present invention, the positive stiffness adjustment unit includes an elastic element, a lifting structure, and a first transmission element. The elastic element is sleeved on the lifting structure, one end of the elastic element is connected to the first plate, and the other end of the elastic element is connected to the lifting structure. The first transmission element is drivingly connected to the lifting structure, and the first transmission element drives the lifting structure to slide in the vertical direction to adjust the positive stiffness in the vertical direction.

[0013] Beneficial effects: The elastic element connects the first plate and the lifting structure, providing vertical support force and positive stiffness to the first plate and the load platform. When the first transmission component drives the lifting structure to move vertically, it can change the support position and working state of the elastic element, thereby adjusting the support height and vertical positive stiffness of the positive stiffness adjustment unit, enabling the first adjustment module to adapt to isolated objects of different weights.

[0014] According to some embodiments of the present invention, the lifting structure includes a limiting guide post fixedly disposed on the base, a receiving frustum and a lifting rod. The receiving frustum is fixedly disposed on the lifting rod and sleeved on the limiting guide post. The elastic element is sleeved on the lifting rod and one end abuts against the receiving frustum. One end of the lifting rod is connected to the first transmission member. The first transmission member drives the lifting rod to move in the vertical direction, so that the receiving frustum slides along the length direction of the limiting guide post.

[0015] Beneficial effects: The receiving frustum is used to support the elastic element. When the lifting rod moves the receiving frustum vertically, it can change the height of the receiving frustum and the support state of the elastic element. The receiving frustum is sleeved on the limiting guide post, which can limit the movement direction of the receiving frustum, reduce the rotation or tilting of the receiving frustum during the lifting process, and enable the receiving frustum to slide more smoothly in the vertical direction, thereby improving the stability and adjustment accuracy of the positive stiffness adjustment process.

[0016] According to some embodiments of the present invention, the first transmission member is a driven wheel, and the driving wheel adjustment structure includes a driving wheel fixed shaft, a driving wheel, a worm gear assembly, an upper fixed block, and a pressure bearing; the driving wheel and the driven wheel are located on the same transmission plane and are respectively connected for transmission; the worm gear assembly is used to drive the driving wheel to rotate, and the driving wheel drives the driven wheel to rotate; The base includes a support base plate, the upper end of the drive wheel fixing shaft is connected to the upper fixing block via the pressure bearing, the lower end of the drive wheel fixing shaft is connected to the drive wheel, and the upper fixing block is connected to the support base plate.

[0017] Beneficial effects: By driving the drive wheel to rotate through the worm gear assembly, and then synchronously driving each driven wheel, the adjustment power can be synchronously transmitted to each stiffness adjustment unit, thereby synchronously adjusting the height of each lifting structure. This synchronous adjustment method can reduce the height difference between different support positions, reducing the possibility of the load platform tilting due to asynchronous adjustment of the stiffness adjustment units. The worm gear assembly can improve the resolution of transmission adjustment, facilitating fine adjustment of the support height of the stiffness adjustment unit.

[0018] The upper fixing block is connected to the support base plate, providing stable support for the drive wheel fixing shaft. A pressure bearing is positioned between the drive wheel fixing shaft and the upper fixing block to bear the axial load at the drive wheel fixing shaft. This helps reduce the resistance of the drive wheel fixing shaft when rotating under load, allowing the drive wheel to drive each driven wheel more smoothly, thereby improving the transmission stability of the drive wheel adjustment structure.

[0019] According to some embodiments of the present invention, the radial adjustment mechanism includes a slide module, a worm gear module, a support platform module, and a slide side plate fixing plate; the slide module is drivenly connected to the worm gear module, the lead screw of the worm gear module passes through the slide module and is connected to the slide side plate fixing plate to drive the slide module to move along the lead screw; one end of the negative stiffness spring is connected to the support platform module, and the other end is connected to the first plate; the slide side plate fixing plate is connected to the second plate.

[0020] Beneficial effects: The worm gear module converts rotational adjustment into radial movement of the slide module along the lead screw. As the slide module moves radially, the distance between the two ends of the negative stiffness spring changes, thereby altering the preload buckling of the negative stiffness spring. By controlling the rotation of the worm gear module, the radial displacement of the slide module can be finely adjusted, thus precisely regulating the negative stiffness generated by the negative stiffness spring and matching it with the positive stiffness of the corresponding support position.

[0021] According to some embodiments of the present invention, the first plate has three circumferentially extending support portions, the three support portions respectively covering the upper ends of the elastic elements of the three sets of positive stiffness adjustment units.

[0022] Beneficial effects: The three support sections of the first plate respectively bear the supporting force provided by the three elastic elements, which can transfer the load borne by the load platform to the three positive stiffness adjustment units, and form a three-point support in conjunction with the three positive stiffness adjustment units. The three support sections extend circumferentially, which helps to increase the range of action between the first plate and the support areas where each elastic element is located, and improves the stability of load transmission.

[0023] According to some embodiments of the present invention, the base base further includes a plurality of support feet connected to the support base plate; the support base plate is provided with through holes for the lifting rod to pass through.

[0024] Beneficial effects: Multiple support feet can transfer the load of the quasi-zero stiffness isolator and the isolated object to the mounting foundation, providing stable support for the quasi-zero stiffness isolator. The through holes on the support base plate provide movement space for the lifting rod's raising and lowering motion, preventing the support base plate from interfering with the adjustment movement of the lifting rod.

[0025] According to some embodiments of the present invention, the load platform includes a load panel and an inclined vibration isolation pad disposed below the load panel.

[0026] Beneficial effects: The load panel provides an installation and bearing surface for the isolated object. The inclined vibration isolation pad is set below the load panel, which helps to form a stable load transfer relationship between the load panel and the first plate and can buffer the local impact or high-frequency vibration of the load platform, thereby improving the support condition of the load platform. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is an axial view of a quasi-zero stiffness vibration isolator according to some specific embodiments of the present invention; Figure 2 This is an axial view of the first adjustment module in some specific embodiments of the present invention; Figure 3 This is a front view of the positive stiffness adjustment unit in some specific embodiments of the present invention; Figure 4 This is a top view of the second adjustment module in some specific embodiments of the present invention; Figure 5 This is an axial view of the negative stiffness adjustment unit in some specific embodiments of the present invention; Figure 6 This is an axial view of the load platform in some specific embodiments of the present invention.

[0029] Explanation of reference numerals in the attached figures: 1. Base; 2. First adjustment module; 3. Second adjustment module; 4. Load platform; 21. Positive stiffness adjustment unit; 22. First plate; 23. Drive wheel adjustment structure; 31. Negative stiffness adjustment unit; 32. Second plate; 41. Load panel; 42. Inclined vibration isolation pad; 211. Elastic element; 212. Receiving frustum; 213. Lifting rod; 214. Limiting guide column; 215. First transmission component; 221. Support part; 311. Negative stiffness spring; 312. Radial adjustment mechanism; 3121. Support platform module; 3122. Worm gear module; 3123. Slide module; 3124. Slide side plate fixing plate. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Reference Figure 1As shown, this embodiment provides a quasi-zero stiffness vibration isolator, including a base 1, a load platform 4, a first adjustment module 2, and a second adjustment module 3. The load platform 4 is disposed on the upper part of the quasi-zero stiffness vibration isolator and is used to install and support the object to be isolated; the base 1 is disposed on the lower part of the quasi-zero stiffness vibration isolator and is used to support the quasi-zero stiffness vibration isolator and install the quasi-zero stiffness vibration isolator on the foundation or other mounting base; the first adjustment module 2 is disposed between the load platform 4 and the base 1 and is used to provide positive stiffness in the vertical direction to the load platform 4; the second adjustment module 3 is disposed on the base 1 and is used to provide negative stiffness in the vertical direction to the load platform 4.

[0032] The positive stiffness provided by the first adjustment module 2 is connected in parallel with the negative stiffness provided by the second adjustment module 3. By adjusting the support state of the first adjustment module 2 and the pre-compression buckling amount of the negative stiffness spring 311 in the second adjustment module 3, the positive stiffness and negative stiffness can be matched with each other near the equilibrium position of the quasi-zero stiffness isolator, so that the equivalent stiffness of the quasi-zero stiffness isolator near the equilibrium position is close to zero, thereby reducing the resonance frequency of the quasi-zero stiffness isolator and improving the low-frequency vibration isolation effect.

[0033] Reference Figure 2 As shown, in some embodiments of the present invention, the first adjustment module 2 includes a first plate 22, a plurality of positive stiffness adjustment units 21, and a drive wheel adjustment structure 23. The upper end of the positive stiffness adjustment unit 21 is connected to the first plate 22, and the lower end of the positive stiffness adjustment unit 21 is connected to the base 1. The load platform 4 is connected above the first plate 22. The load borne by the load platform 4 is transmitted to each positive stiffness adjustment unit 21 through the first plate 22, and each positive stiffness adjustment unit 21 jointly provides vertical support force and positive stiffness to the load platform 4.

[0034] This embodiment uses three positive stiffness adjustment units 21 as an example. The three positive stiffness adjustment units 21 are distributed circumferentially at 120° around the center of the quasi-zero stiffness vibration isolator, and the centers of the three positive stiffness adjustment units 21 can form an equilateral triangle. The load borne by the load platform 4 is transmitted to the three positive stiffness adjustment units 21 through the first plate 22, thereby forming a three-point support structure.

[0035] In this embodiment, the three positive stiffness adjustment units 21 are evenly distributed around the center of the quasi-zero stiffness isolator, which can distribute the load borne by the load platform 4 to three support positions. The three-point support structure helps to improve the support stability of the load platform 4, reduce the possibility of the load platform 4 tilting or overturning, and reduce the sensitivity of the quasi-zero stiffness isolator to the placement position of the isolated object.

[0036] The first plate 22 has three circumferentially extending support portions 221, which respectively cover the upper ends of the elastic elements 211 of the three positive stiffness adjustment units 21. The three support portions 221 are used to receive the supporting force provided by the three elastic elements 211 and to transfer the load borne by the load platform 4 to the three positive stiffness adjustment units 21.

[0037] The first plate 22 can be a one-piece molded structure or formed by connecting multiple plate components. The specific shape of the first plate 22 can be determined according to the arrangement of the three positive stiffness adjustment units 21 and the shape of the load platform 4, as long as the load transfer between the load platform 4, the positive stiffness adjustment units 21 and the negative stiffness spring 311 can be realized.

[0038] Reference Figure 3 As shown, in some embodiments of the present invention, each positive stiffness adjustment unit 21 includes an elastic element 211, a lifting structure, and a first transmission element 215. The elastic element 211 is sleeved on the lifting structure, one end of the elastic element 211 is connected to the first plate 22, and the other end of the elastic element 211 is connected to the lifting structure. The first transmission element 215 is connected to the lifting structure for driving the lifting structure to move in the vertical direction.

[0039] The elastic element 211 can be a compression spring. The compression spring is pressed between the first plate 22 and the lifting structure to provide vertical support force and normal stiffness to the first plate 22 and the load platform 4. When the lifting structure moves in the vertical direction, the support position of the lower end of the elastic element 211 and the working state of the elastic element 211 can be changed, thereby adjusting the support height and equivalent normal stiffness of the normal stiffness adjustment unit 21.

[0040] In other embodiments, the elastic element 211 may also adopt other elastic structures that can generate vertical elastic restoring force, and the present invention does not limit the specific type of the elastic element 211.

[0041] Reference Figure 3 As shown, in some embodiments of the present invention, the lifting structure includes a limiting guide post 214, a receiving frustum 212, and a lifting rod 213. The limiting guide post 214 is fixedly mounted on the base 1, and the receiving frustum 212 is fixedly mounted on the lifting rod 213 and sleeved on the limiting guide post 214. An elastic element 211 is sleeved on the lifting rod 213, with its upper end connected to the first plate 22 and its lower end abutting against the receiving frustum 212.

[0042] The first transmission component 215 is connected to the lifting rod 213. When the first transmission component 215 is activated, it drives the lifting rod 213 to move vertically. The lifting rod 213 drives the receiving platform 212 to slide along the length of the limiting guide post 214, thereby changing the height of the receiving platform 212 relative to the base 1.

[0043] In this embodiment, the receiving frustum 212 is used to receive the lower end of the elastic element 211. When the receiving frustum 212 moves in the vertical direction, it can change the support position and compression state of the elastic element 211. The limiting guide post 214 is used to limit the movement direction of the receiving frustum 212, reducing the rotation or lateral displacement of the receiving frustum 212 during the lifting and lowering process, so that the receiving frustum 212 can move more smoothly in the vertical direction, thereby improving the stability of the positive stiffness adjustment process.

[0044] To convert the motion of the first transmission member 215 into the vertical motion of the lifting rod 213, a transmission pair capable of converting rotational motion into linear motion can be provided between the first transmission member 215 and the lifting rod 213. For example, the first transmission member 215 can be provided with a threaded transmission part, and the lifting rod 213 can be provided with an external thread that mates with the threaded transmission part. When the first transmission member 215 rotates relative to the base 1, the lifting rod 213 moves vertically under the constraint of the receiving frustum 212 and the limiting guide post 214.

[0045] In other embodiments, the first transmission member 215 and the lifting rod 213 may also adopt other transmission structures that can convert the motion of the first transmission member 215 into the vertical motion of the lifting rod 213. The present invention does not limit the specific transmission form between the two.

[0046] In some embodiments of the present invention, the first transmission member 215 is a driven wheel, and the driving wheel adjustment structure 23 includes a driving wheel fixed shaft, a driving wheel, a worm gear assembly, an upper fixed block, and a pressure bearing. The driving wheel and the driven wheels of the three positive stiffness adjustment units 21 are on the same transmission plane and are respectively connected to the three driven wheels in a transmission connection.

[0047] The driving wheel can directly mesh with the three driven wheels, or it can be connected to the three driven wheels through an intermediate transmission component. When the driving wheel rotates, it can synchronously drive the three driven wheels to rotate, and the three driven wheels respectively drive the corresponding lifting rods 213 to move in the vertical direction, thereby synchronously changing the height of the three supporting truncated cones 212.

[0048] The worm gear assembly is used to drive the rotation of the driving wheel. When operating the worm gear assembly, it transmits the adjustment power to the driving wheel, which synchronously drives the three driven wheels to rotate. The three driven wheels respectively drive the corresponding lifting rod 213 and the receiving frustum 212 to move in the vertical direction, thereby synchronously adjusting the support height of the three positive stiffness adjustment units 21.

[0049] In this embodiment, by synchronously driving three driven wheels with one driving wheel, the height adjustment error among the three positive stiffness adjustment units 21 can be reduced, thus lowering the possibility of the load platform 4 tilting due to inconsistent adjustment amounts at the three support positions. The worm gear assembly can provide a large transmission ratio, facilitating fine control of the rotation amount of the driving wheel, thereby improving the adjustment accuracy of the support height of the positive stiffness adjustment unit 21.

[0050] The base 1 includes a support base plate. The upper end of the drive wheel fixing shaft is connected to the upper fixing block via a pressure bearing, the lower end of the drive wheel fixing shaft is connected to the drive wheel, and the upper fixing block is connected to the support base plate. The drive wheel fixing shaft is used to support the drive wheel and limit its rotational position.

[0051] The pressure bearing is used to bear the axial load at the fixed shaft of the drive wheel, so that the drive wheel can still rotate relatively smoothly when bearing the load from the first adjustment module 2 and the load platform 4, thereby reducing the rotational resistance of the drive wheel and improving the transmission stability of the drive wheel adjustment structure 23.

[0052] The support base plate has through holes for the three lifting rods 213 to pass through. The lifting rods 213 can move vertically within the corresponding through holes, and the through holes provide movement space for the lifting rods 213, avoiding interference from the support base plate on the lifting movement of the lifting rods 213.

[0053] The base 1 also includes multiple support feet connected to the support base plate. The multiple support feet are distributed below the support base plate and are used to transfer the load of the quasi-zero stiffness vibration isolator and the isolated object to the foundation or other mounting base.

[0054] The support feet can be connected to the support base plate via threaded connections, fastener connections, or welding. The support feet can also have a height-adjustable structure to allow for leveling of the foundation base 1 during the installation of the quasi-zero stiffness vibration isolator.

[0055] Reference Figure 4 As shown, in some embodiments of the present invention, the second adjustment module 3 includes a second plate 32 and a plurality of negative stiffness adjustment units 31. The second plate 32 is disposed on the base 1 and provides a common mounting base for each negative stiffness adjustment unit 31. Each negative stiffness adjustment unit 31 is disposed on the second plate 32 and corresponds to a corresponding positive stiffness adjustment unit 21.

[0056] This embodiment uses three negative stiffness adjustment units 31 as an example. The three negative stiffness adjustment units 31 are distributed circumferentially at 120° around the center of the quasi-zero stiffness vibration isolator, and are evenly spaced from the three positive stiffness adjustment units 21 along the circumference. The positive stiffness adjustment units 21 and negative stiffness adjustment units 31 can be arranged alternately along the circumference, so that the positions of positive stiffness application and negative stiffness application are dispersed along the circumference.

[0057] In this embodiment, the negative stiffness adjustment unit 31 and the positive stiffness adjustment unit 21 are arranged in a corresponding manner, which means that there is a one-to-one functional relationship between the three negative stiffness adjustment units 31 and the three positive stiffness adjustment units 21. Each negative stiffness adjustment unit 31 is used to adjust the negative stiffness of the corresponding support area, without requiring the negative stiffness adjustment unit 31 and the corresponding positive stiffness adjustment unit 21 to be located on the same radial line.

[0058] By distributing the three positive stiffness adjustment units 21 and the three negative stiffness adjustment units 31 evenly along the circumference, the positions of positive stiffness action and negative stiffness action can be reasonably dispersed, which is beneficial to improving the stress state of the first plate 22 and the load platform 4, and provides an adjustment basis for the positive and negative stiffness matching of each support area.

[0059] Reference Figure 5 As shown, each negative stiffness adjustment unit 31 includes a negative stiffness spring 311 and a radial adjustment mechanism 312. The radial adjustment mechanism 312 includes a slide module 3123, a worm gear module 3122, a support platform module 3121, and a slide side plate fixing plate 3124. The slide side plate fixing plate 3124 is connected to the second plate 32 and is used to provide an installation and support base for the slide module 3123 and the worm gear module 3122.

[0060] The worm gear module 3122 includes a lead screw that passes through the slide module 3123 and is connected to the slide side plate fixing plate 3124. The slide module 3123 is driven by the worm gear module 3122 and can move along the lead screw under the drive of the worm gear module 3122. A transmission part that threadedly engages with the lead screw can be provided in the slide module 3123 to convert the rotation of the lead screw into linear movement of the slide module 3123 along the lead screw.

[0061] The support platform module 3121 is mounted on the slide platform module 3123 and can move radially with the slide platform module 3123. One end of the negative stiffness spring 311 is connected to the support platform module 3121, and the other end of the negative stiffness spring 311 is connected to the first plate 22. Both ends of the negative stiffness spring 311 are subjected to pre-compression along its length, so that the negative stiffness spring 311 is in a pre-compression buckling state.

[0062] When the first plate 22 is displaced in the vertical direction under load or external vibration, the negative stiffness spring 311 undergoes corresponding buckling deformation and provides negative stiffness in the vertical direction to the first plate 22 within the predetermined working range.

[0063] When the worm gear module 3122 is operated, it drives the lead screw to rotate. The rotation of the lead screw is converted into the linear movement of the slide module 3123 in the radial direction. The support platform module 3121 moves radially with the slide module 3123, thereby changing the distance between the support platform module 3121 and the corresponding connection position on the first plate 22, and changing the pre-compression buckling amount of the negative stiffness spring 311.

[0064] In this embodiment, by controlling the rotation of the worm gear module 3122, the radial displacement of the slide module 3123 and the support platform module 3121 can be finely adjusted, thereby precisely adjusting the preload buckling amount and negative stiffness characteristics of the negative stiffness spring 311. Each negative stiffness adjustment unit 31 is equipped with a corresponding worm gear module 3122, so it can be adjusted according to the force state of different support areas.

[0065] When the center of gravity of the isolated object deviates from the center of the load platform 4, the loads borne by the three positive stiffness adjustment units 21 may differ. At this time, the worm gear modules 3122 of the three negative stiffness adjustment units 31 can be operated separately to make the preload buckling amount of each negative stiffness spring 311 adapt to the stress state of the corresponding support area, thereby compensating for the local positive and negative stiffness mismatch caused by the off-center load.

[0066] For inconsistent stress in different support areas caused by manufacturing errors, assembly errors, or installation errors of the base 1, the radial position of the corresponding negative stiffness adjustment unit 31 can be adjusted to match the negative stiffness with the positive stiffness of each support area.

[0067] Reference Figure 6 As shown, in some embodiments of the present invention, the load platform 4 includes a load panel 41 and an inclined vibration isolation pad 42 disposed below the load panel 41. The load panel 41 is used to provide an installation and bearing surface for the object to be isolated, and the inclined vibration isolation pad 42 is disposed between the load panel 41 and the first plate 22.

[0068] The load generated by the isolated object is sequentially transmitted through the load panel 41, the inclined vibration isolation pad 42, and the first plate 22 to the three positive stiffness adjustment units 21 and the three negative stiffness adjustment units 31. The specific shape, tilt direction, and tilt angle of the inclined vibration isolation pad 42 can be determined according to the structure of the load platform 4, the installation method of the isolated object, and the load transmission requirements.

[0069] The installation and adjustment process of this embodiment will be described below.

[0070] During installation, the base 1 is first placed on the ground or other mounting foundation, and the support state of the base 1 is adjusted by multiple support feet. Then, the second plate 32 and three negative stiffness adjustment units 31 are installed on the base 1, and the three positive stiffness adjustment units 21 and the drive wheel adjustment structure 23 are installed on the support base plate.

[0071] When installing the drive wheel adjustment structure 23, the drive wheel and the three driven wheels are positioned on the same transmission plane and connected to each other via transmission. The first plate 22 is installed above the three positive stiffness adjustment units 21, with the three support portions 221 of the first plate 22 connected to the upper ends of the three elastic elements 211, and the three negative stiffness springs 311 connected to their respective connection positions on the first plate 22. Finally, the load platform 4 is connected to the first plate 22, and the object to be isolated is installed on the load panel 41.

[0072] When adjusting the positive stiffness, the worm gear assembly is operated according to the weight of the object being isolated. The worm gear assembly drives the driving wheel to rotate, which in turn drives the three driven wheels to rotate synchronously. The three driven wheels then drive the corresponding lifting rods 213 to move vertically.

[0073] When the lifting rod 213 moves, it drives the receiving platform 212 to move along the length direction of the limiting guide column 214, so that the three receiving platforms 212 rise and fall synchronously. By adjusting the height of the receiving platform 212, the support position and working state of the three elastic elements 211 can be changed, so that the load platform 4 reaches the predetermined support height and maintains basic balance.

[0074] When adjusting the negative stiffness, the worm gear modules 3122 of the three negative stiffness adjustment units 31 are operated respectively, so that the corresponding slide module 3123 and support platform module 3121 move radially, and the pre-compression buckling amount of the three negative stiffness springs 311 is changed respectively.

[0075] For an isolated object with its center of gravity basically centered, the three negative stiffness springs 311 can be adjusted to have essentially the same pre-compression buckling state. For off-center loading conditions, the pre-compression buckling of the three negative stiffness springs 311 can be adjusted separately according to the difference in loads borne by the three support areas, so that the negative stiffness of each support area matches the corresponding positive stiffness.

[0076] During the adjustment process, the first adjustment module 2 and the second adjustment module 3 can be adjusted multiple times according to the horizontal state of the load platform 4, the static deformation of each support area, or the dynamic response of the quasi-zero stiffness vibration isolator, until the load platform 4 remains stable and the positive stiffness and negative stiffness reach a predetermined matching state near the equilibrium position.

[0077] After adjustment, the positive stiffness provided by the positive stiffness adjustment unit 21 and the negative stiffness provided by the negative stiffness adjustment unit 31 cancel each other out near the equilibrium position, making the equivalent stiffness of the quasi-zero stiffness isolator close to zero. When the load platform 4 is subjected to a small amplitude vertical vibration, the quasi-zero stiffness isolator can respond with a lower equivalent stiffness, thereby reducing the transmission of vibration from the installation foundation to the isolated object.

[0078] When the weight or center of gravity of the isolated object changes, the active wheel adjustment structure 23 can be restarted to synchronously adjust the support height of the three positive stiffness adjustment units 21; then the radial positions of the three negative stiffness adjustment units 31 are adjusted respectively to make the pre-compression buckling amount of each negative stiffness spring 311 adapt to the changed load state.

[0079] Therefore, by synchronously adjusting the support height of the positive stiffness adjustment unit 21 and adjusting the pre-compression buckling amount of the negative stiffness spring 311 respectively, the overall balance of the load platform 4 and the matching of positive and negative stiffness in each support area can be taken into account, so that the quasi-zero stiffness vibration isolator can still obtain a relatively stable quasi-zero stiffness vibration isolation state under different loads or off-center load conditions.

[0080] It should be noted that this embodiment uses three positive stiffness adjustment units 21 and three negative stiffness adjustment units 31 as examples for illustration. Without changing the inventive concept of multi-point support, synchronous adjustment of the positive stiffness support state, and radial adjustment of the pre-compression buckling amount of the negative stiffness spring 311, more positive stiffness adjustment units 21 and negative stiffness adjustment units 31 can be set according to the size of the load platform 4, the weight of the isolated object, and the installation space, and the structure of the driving wheel, driven wheel, first plate 22, and second plate 32 can be adjusted accordingly.

[0081] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A quasi-zero stiffness vibration isolator, characterized in that, include: Basic base (1); The load platform (4) is used to support the isolated object; The first adjustment module (2) is disposed between the load platform (4) and the base (1). The first adjustment module (2) includes a first plate (22) and a plurality of positive stiffness adjustment units (21). The upper end of the positive stiffness adjustment unit (21) is connected to the first plate (22), and the lower end of the positive stiffness adjustment unit (21) is connected to the base (1). The first plate (22) is connected to the load platform (4). The positive stiffness adjustment unit (21) is used to provide positive stiffness in the vertical direction to the load platform (4). The second adjustment module (3) is disposed on the base (1). The second adjustment module (3) includes several negative stiffness adjustment units (31). The negative stiffness adjustment units (31) are disposed corresponding to the positive stiffness adjustment units (21). The negative stiffness adjustment unit (31) includes a negative stiffness spring (311) and a radial adjustment mechanism (312). The radial adjustment mechanism (312) is used to adjust the pre-compression buckling amount of the negative stiffness spring (311) in the radial direction. The negative stiffness spring (311) is connected to the first plate (22) and is used to provide negative stiffness in the vertical direction. The positive stiffness provided by the positive stiffness adjustment unit (21) is connected in parallel with the negative stiffness provided by the negative stiffness adjustment unit (31) so that the quasi-zero stiffness isolator exhibits quasi-zero stiffness characteristics near the equilibrium position.

2. The quasi-zero stiffness vibration isolator according to claim 1, characterized in that, The positive stiffness adjustment unit (21) is provided in at least three parts, and the three positive stiffness adjustment units (21) are distributed in a 120° circumferential direction; At least three negative stiffness adjustment units (31) are provided, and the three negative stiffness adjustment units (31) are distributed in a 120° circumferential direction. The three negative stiffness adjustment units (31) and the three positive stiffness adjustment units (21) are arranged at a uniform interval along the circumferential direction.

3. The quasi-zero stiffness vibration isolator according to claim 2, characterized in that, The second adjustment module (3) further includes a second plate (32), which is disposed on the base (1), and a plurality of negative stiffness adjustment units (31) are disposed on the second plate (32); The first adjustment module (2) further includes an active wheel adjustment structure (23), which is connected to the positive stiffness adjustment unit (21) for synchronous adjustment of the support height of the three sets of positive stiffness adjustment units (21).

4. The quasi-zero stiffness vibration isolator according to claim 3, characterized in that, The positive stiffness adjustment unit (21) includes an elastic element (211), a lifting structure and a first transmission element (215). The elastic element (211) is sleeved on the lifting structure. One end of the elastic element (211) is connected to the first plate (22), and the other end of the elastic element (211) is connected to the lifting structure. The first transmission element (215) is connected to the lifting structure in a transmission manner. The first transmission element (215) drives the lifting structure to slide in the vertical direction to adjust the positive stiffness in the vertical direction.

5. The quasi-zero stiffness vibration isolator according to claim 4, characterized in that, The lifting structure includes a limiting guide post (214), a receiving truncated cone (212), and a lifting rod (213). The limiting guide post (214) is fixedly mounted on the base (1). The receiving truncated cone (212) is fixedly mounted on the lifting rod (213), and the receiving truncated cone (212) is sleeved on the limiting guide post (214). The elastic element (211) is sleeved on the lifting rod (213), and one end of it abuts against the receiving truncated cone (212). One end of the lifting rod (213) is connected to the first transmission element (215). The first transmission element (215) drives the lifting rod (213) to move in the vertical direction, so that the receiving truncated cone (212) slides along the length direction of the limiting guide post (214).

6. The quasi-zero stiffness vibration isolator according to claim 5, characterized in that, The first transmission component (215) is a driven wheel, and the driving wheel adjustment structure (23) includes a driving wheel fixed shaft, a driving wheel, a worm gear assembly, an upper fixed block and a pressure bearing; the driving wheel and the driven wheel are on the same transmission plane and are connected in transmission, the worm gear assembly is used to drive the driving wheel to rotate, and the driving wheel drives the driven wheel to rotate; The base (1) includes a support base plate, the upper end of the drive wheel fixing shaft is connected to the upper fixing block via the pressure bearing, the lower end of the drive wheel fixing shaft is connected to the drive wheel, and the upper fixing block is connected to the support base plate.

7. The quasi-zero stiffness vibration isolator according to claim 4, characterized in that, The radial adjustment mechanism (312) includes a slide module (3123), a worm gear module (3122), a support platform module (3121), and a slide side plate fixing plate (3124). The slide module (3123) is connected to the worm gear module (3122) in a transmission connection. The lead screw of the worm gear module (3122) passes through the slide module (3123) and is connected to the slide side plate fixing plate (3124) to drive the slide module (3123) to move along the lead screw. One end of the negative stiffness spring (311) is connected to the support platform module (3121), and the other end is connected to the first plate (22). The slide side plate fixing plate (3124) is connected to the second plate (32).

8. The quasi-zero stiffness vibration isolator according to claim 7, characterized in that, The first plate (22) has three circumferentially extending support portions (221), which respectively cover the upper end of the elastic element (211) of the three sets of positive stiffness adjustment units (21).

9. The quasi-zero stiffness vibration isolator according to claim 6, characterized in that, The base (1) also includes a plurality of support feet connected to the support base plate; the support base plate is provided with through holes through which the lifting rod (213) passes.

10. The quasi-zero stiffness vibration isolator according to claim 1, characterized in that, The load platform (4) includes a load panel (41) and an inclined vibration isolation pad (42) disposed below the load panel (41).

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