Quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action and installation method

Abstract

The application discloses a quasi-zero stiffness vibration isolation support suitable for oblique seismic action and a mounting method, relates to the technical field of seismic isolation and damping support, and comprises a lower supporting seat, an upper bearing platform above the lower supporting seat, a vertical air spring unit between the lower supporting seat and the upper bearing platform, and a horizontal negative stiffness unit around the vertical air spring unit on the lower supporting seat. The horizontal negative stiffness unit comprises a fixed support on the lower supporting seat, at least two horizontal air springs arranged on the fixed support, and a connecting rod hinged to the horizontal air springs away from the fixed support. One end of the connecting rod away from the horizontal air springs is hinged to the bottom surface of the upper bearing platform. The horizontal air springs are uniformly arranged around the vertical air spring unit. Under oblique seismic action, the vertical, horizontal and tilting displacements can be smoothly transmitted to the corresponding horizontal air springs in a self-adaptive manner, and the additional bending moment and the jamming problem of the traditional planar connecting rod structure are avoided.

Description

Technical Field

[0001] This invention relates to the field of seismic isolation and vibration reduction bearing technology, specifically to a quasi-zero stiffness vibration isolation bearing and installation method suitable for oblique seismic action, and more particularly to a method for achieving oblique seismic vibration isolation by utilizing a vertical air spring unit, a circumferentially arranged horizontal air spring, a spatially hinged connecting rod, a limit and reset assembly, and a pneumatic pressure regulating assembly in synergy. Background Technology

[0002] Air springs are characterized by adjustable stiffness, adjustable load capacity, and good low-frequency vibration isolation performance. Quasi-zero stiffness vibration isolators based on the principle of parallel positive and negative stiffness typically use a positive stiffness mechanism to bear the static load and a negative stiffness mechanism to offset part of the positive stiffness, so that the system obtains a lower dynamic stiffness near the static equilibrium position, thereby improving the low-frequency vibration isolation effect.

[0003] Existing research has identified air spring quasi-zero stiffness vibration isolators that employ one vertical air spring as the positive stiffness mechanism and two horizontal symmetrical air springs as the negative stiffness mechanism. In this type of structure, the horizontal air springs transmit force to the load-bearing platform through connecting rods, causing the deformation of the horizontal air springs to form a component force in the vertical direction, thereby achieving quasi-zero stiffness characteristics.

[0004] However, when these vibration isolators are used as seismic isolation bearings for building, bridge, or equipment foundations, the seismic force is often not simply input vertically, but may be transmitted to the foundation obliquely, causing the superstructure to simultaneously experience vertical, horizontal, and tilting displacements. Traditional planar linkage-type force transmission structures are prone to problems such as bending of connecting rods, jamming at hinges, uneven loading of horizontal air springs, and localized stress concentration under oblique seismic input, affecting the seismic isolation effect and safety of the bearings.

[0005] Therefore, it is necessary to develop and design quasi-zero stiffness vibration isolation bearings and installation methods suitable for oblique seismic action, which can adapt to oblique seismic action, allow the connecting rod to swing and transmit force in space, and take into account the quasi-zero stiffness vibration isolation performance. This is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a quasi-zero stiffness vibration isolation bearing and its installation method suitable for oblique seismic action. This bearing can adapt to oblique seismic action, allow the connecting rod to swing and transmit force in space, and also maintain quasi-zero stiffness vibration isolation performance.

[0007] To achieve the above objectives, the present invention provides the following solution: A quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action includes a lower support, an upper bearing platform disposed above the lower support, a vertical air spring unit disposed between the lower support and the upper bearing platform, and horizontal negative stiffness units disposed on the lower support around the vertical air spring units. The horizontal negative stiffness unit includes a fixed bracket disposed on the lower support, at least two horizontal air springs disposed on the fixed bracket, and a connecting rod hinged to one end of the horizontal air springs away from the fixed bracket. The end of the connecting rod away from the horizontal air springs is hinged to the bottom surface of the upper bearing platform. The horizontal air springs are evenly distributed around the vertical air spring units.

[0008] Preferably, there are four horizontal air springs arranged in a cross shape.

[0009] Preferably, a horizontal guide assembly is provided on the lower support seat. The horizontal guide assembly includes a guide rail disposed on the lower support seat and a slider slidably connected to the guide rail. The slider is connected to the side of the horizontal air spring near the lower support seat and the side of the horizontal air spring near the connecting rod.

[0010] Preferably, the system further includes a limit reset assembly, which includes a central limit post with one end hinged to the lower support seat and the other end connected to the upper support platform, and a limit cylinder disposed around the central limit post. The bottom of the limit cylinder is connected to the lower support seat, and the top of the limit cylinder is spaced apart from the upper support platform. The outer diameter of the central limit post is smaller than the inner diameter of the limit cylinder.

[0011] Preferably, the limiting and resetting assembly further includes at least three circumferential resetting elastic elements surrounding the outer periphery of the vertical air spring unit.

[0012] Preferably, an elastic buffer layer is provided on the outer wall of the central limiting post and / or the inner wall of the limiting cylinder.

[0013] Preferably, a first ball joint is provided between the horizontal air spring and the connecting rod, and a second ball joint is provided between the connecting rod and the upper bearing platform. Both the first ball joint and the second ball joint include a ball seat, a ball head provided on the ball seat, and an anti-detachment pressure cap provided on the ball seat to limit the ball head. A wear-resistant bushing is provided between the ball head and the ball seat.

[0014] Preferably, the connecting rod includes a first rod segment and a second rod segment, and a threaded adjusting sleeve is provided between the first rod segment and the second rod segment. The threaded adjusting sleeve is threadedly connected to the first rod segment and the second rod segment to realize the length adjustment of the connecting rod.

[0015] Preferably, the system further includes a pressure regulating assembly, which includes an inflation valve and an exhaust valve communicating with the airbags in the horizontal air spring and the vertical air spring unit, a pressure detection element disposed inside the airbag, an inclination detection element and a horizontal displacement detection element disposed on the upper support platform and the lower support seat, and a control system electrically connected to the inflation valve, the exhaust valve, the pressure detection element, the horizontal displacement detection element and the inclination detection element.

[0016] This invention also discloses an installation method for a quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action, comprising the following steps: The lower support is connected to the foundation structure, the upper bearing platform is connected to the upper structure, and a vertical air spring unit is set between the lower support and the upper bearing platform so that the vertical air spring unit can bear the vertical static load and provide vertical positive stiffness. A horizontal negative stiffness unit is provided around the vertical air spring unit. The horizontal negative stiffness unit includes a fixed bracket, at least two horizontal air springs, and a connecting rod. One end of the horizontal air spring is connected to the fixed bracket, and the other end is hinged to the bottom surface of the upper bearing platform via the connecting rod. Through the synergistic effect of the positive stiffness of the vertical air spring unit and the horizontal negative stiffness generated by each horizontal air spring via the connecting rod, the vibration isolation support forms a quasi-zero stiffness working state near the static equilibrium position. When an oblique seismic force is introduced, the vertical, horizontal and tilting displacements of the upper bearing platform relative to the lower support are transmitted to the corresponding horizontal air springs by utilizing the spatial swing of the connecting rod relative to the horizontal air spring and the upper bearing platform. When the displacement or tilt of the upper bearing platform exceeds the preset range, the excessive deformation is limited by the limit and reset component, and the upper bearing platform is assisted to reset after the seismic action weakens.

[0017] Preferably, an air pressure regulating component is installed. The air pressure regulating component is used to collect and regulate the air pressure of the horizontal air spring and / or the vertical air spring unit, and to collect the attitude and displacement of the upper bearing platform relative to the lower support seat, so that the vertical positive stiffness and the horizontal negative stiffness are matched.

[0018] The present invention achieves the following technical effects compared to the prior art: By uniformly arranging multiple horizontal air springs around the vertical air spring unit and hinged at both ends of the connecting rod to the horizontal air spring and the upper bearing platform respectively to achieve spatial swing connection, the vertical, horizontal and tilt displacements can be smoothly and adaptively transferred to the corresponding horizontal air springs under oblique seismic action, effectively avoiding the additional bending moment and jamming problems of traditional planar linkage structures. At the same time, the vertical air spring provides positive stiffness and the horizontal air spring provides negative stiffness. The two work together to form a multi-directional quasi-zero stiffness characteristic, which significantly reduces the initial vibration isolation frequency and suppresses resonance transmission. Combined with the limit and reset components to constrain excessive deformation, the bearing's adaptability to oblique ground motion, force transmission smoothness and post-earthquake reset reliability are greatly improved while ensuring high load-bearing capacity and low-frequency vibration isolation performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Appendix Figure 1 This is a schematic diagram of the overall structure of the quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action disclosed in this invention; Appendix Figure 2 For the appendix Figure 1 Cross-sectional view of the structure in the CC direction; Appendix Figure 3 This is a cross-sectional structural schematic diagram of the ball joint node in the quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action disclosed in this invention. Appendix Figure 4 This is a top view schematic diagram of multiple horizontal negative stiffness elements orthogonally arranged in a quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action disclosed in this invention. Appendix Figure 5 This is a schematic diagram of the limiting and resetting assembly in a quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action, as disclosed in this invention. Appendix Figure 6 This is a schematic diagram of the spatial swing force transmission of the connecting rod under oblique seismic action of the quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action disclosed in this invention. Appendix Figure 7 This is a schematic diagram of the air pressure regulation steps in a quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action, as disclosed in this invention. The components include: 1. Lower support seat; 2. Upper bearing platform; 3. Vertical air spring unit; 4. Horizontal negative stiffness unit; 41. Horizontal air spring; 42. Connecting rod; 421. First rod segment; 422. Second rod segment; 423. Threaded adjusting sleeve; 43. First ball joint; 44. Second ball joint; 45. Fixed bracket; 46. Horizontal guide assembly; 5. Limiting and resetting assembly; 51. Central limiting post; 52. Limiting cylinder; 53. Elastic buffer layer; 54. Circumferential resetting elastic element; 6. Ball head; 7. Ball seat; 8. Anti-detachment pressure cover; 9. Wear-resistant bushing; 10. Air pressure regulating assembly; 101. Inflation valve; 102. Exhaust valve; 103. Pressure detection element; 11. Inclination angle detection element; 12. Horizontal displacement detection element; 13. Control system. Detailed Implementation

[0021] 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, and 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.

[0022] The purpose of this invention is to provide a quasi-zero stiffness vibration isolation bearing and its installation method suitable for oblique seismic action, which can adapt to oblique seismic action, allow the connecting rod to swing in space to transmit force, and take into account the quasi-zero stiffness vibration isolation performance.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1: refer to Figures 1-7The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action disclosed in this embodiment of the invention includes at least a lower support 1. An upper bearing platform 2 is disposed above the lower support 1. A vertical air spring unit 3 is disposed between the lower support 1 and the upper bearing platform 2. One end of the vertical air spring unit 3 is connected to the top surface of the lower support 1, and the other end is connected to the bottom surface of the upper bearing platform 2. A horizontal negative stiffness unit 4 is disposed on the lower support 1. The horizontal negative stiffness unit 4 includes a fixed bracket 45 disposed on the support 1. At least two horizontal air springs 41 are disposed on the fixed bracket 45. The end of the horizontal air spring 41 away from the fixed bracket 45 is hinged to a connecting rod 42, and the end of the connecting rod 42 away from the horizontal air spring 41 is hinged to the bottom surface of the upper bearing platform 2. The horizontal air springs 41 are evenly distributed vertically. Around the air spring unit 3, multiple horizontal air springs 41 are evenly distributed around the vertical air spring unit 3, and the two ends of the connecting rod 42 are hinged to the horizontal air springs 41 and the upper bearing platform 2 respectively to achieve spatial swing connection. Under oblique earthquake action, it can adaptively and smoothly transmit vertical, horizontal and tilt displacements to the corresponding horizontal air springs 41, effectively avoiding the additional bending moment and jamming problem of traditional planar linkage structure. At the same time, the vertical air springs provide positive stiffness and the horizontal air springs 41 provide negative stiffness. The two work together to form a multi-directional quasi-zero stiffness characteristic, which significantly reduces the initial vibration isolation frequency and suppresses resonance transmission. With the limit and reset component 5 to constrain excessive deformation, the bearing capacity and low frequency vibration isolation performance are guaranteed, and the adaptability of the support to oblique ground motion, the smoothness of force transmission and the reliability of post-earthquake reset are greatly improved.

[0025] It should be noted that the upper bearing platform 2 is connected to the upper structure of the building or the component to be damped, the lower support 1 is connected to the foundation structure of the building or the component to be damped, and the vertical air spring unit 3 is the vertical air spring.

[0026] refer to Figure 4 In one embodiment, four horizontal air springs 41 are arranged in a cross shape, enabling the quasi-zero stiffness vibration isolation bearing to independently and symmetrically provide horizontal negative stiffness in two mutually perpendicular horizontal directions, thereby effectively responding to any horizontal seismic component obtained by decomposition under oblique earthquake action. When an oblique earthquake is introduced from any direction, the four horizontal air springs 41 arranged in a cross shape work together to ensure that the upper bearing platform 2 relative to the lower support 1 obtains balanced quasi-zero stiffness vibration isolation performance in two orthogonal directions, avoiding the stiffness asymmetry problem that may occur with traditional diagonal arrangement. At the same time, the ends of each horizontal air spring 41 are spatially oscillatingly connected to the connecting rod 42 and the upper bearing platform 2 via ball joint nodes, which can adaptively transmit vertical, horizontal and tilt displacements, significantly improving the bearing's adaptability to complex oblique earthquake motion, force transmission smoothness and overall seismic isolation reliability.

[0027] refer to Figure 2 In one embodiment, a horizontal guide assembly 46 is provided on the lower support 1. The horizontal guide assembly 46 includes a guide rail and a slider on the lower support 1. The slider is slidably connected to the guide rail and connected to the side of the horizontal air spring 41 near the lower support 1. By providing the horizontal guide assembly 46 and connecting the slider to the side of the horizontal air spring 41 near the lower support 1, the horizontal air spring 41 can be guided to move strictly along its own axial direction, effectively limiting its lateral sway and torsion. This avoids the off-center load and additional bending stress on the horizontal air spring 41 caused by the spatial swing of the upper bearing platform 2 under oblique earthquake action. The sliding cooperation between the guide rail and the slider ensures the smoothness of the movement and the repeatability of the positioning accuracy of the horizontal air spring 41 during the reciprocating compression and rebound process, reduces the risk of abnormal friction and jamming outside the ball joint node, improves the output stability and service life of the horizontal negative stiffness unit 4, and makes the negative stiffness characteristics provided by the horizontal air spring 41 more linear and controllable, which is conducive to maintaining the consistency of the vibration isolation performance of the support in the multi-directional quasi-zero stiffness state.

[0028] refer to Figure 2 In one implementation, the slider is connected to the side of the horizontal air spring 41 near the connecting rod 42. After the slider is connected to the movable end near the connecting rod 42, it can directly guide the horizontal air spring 41 to move from near the force point, preventing the movable end from shifting, being overloaded, or bending due to the swing of the connecting rod 42, and ensuring the stability and repeatability of the negative stiffness output.

[0029] refer to Figure 5As one implementation, it also includes a limit and reset assembly 5, which includes a central limit post 51. One end of the central limit post 51 is hinged to the lower support seat 1, and the other end of the central post is connected to the upper bearing platform 2. A limit cylinder 52 is sleeved on the outer periphery of the central limit post 51. The bottom of the limit cylinder 52 is connected to the lower support seat 1, and there is a gap between the top of the limit cylinder 52 and the upper bearing platform 2. The outer diameter of the central limit post 51 is smaller than the inner diameter of the limit cylinder 52, which allows the upper bearing platform 2 to generate the required vertical, horizontal, and tilting displacements relative to the lower support seat 1 within the normal vibration isolation working range without contact interference, ensuring that the quasi-zero stiffness vibration isolation performance is fully utilized. When the oblique seismic action causes displacement or tilting to exceed the preset safety range, the outer side of the central limiting column 51 contacts the inner wall of the limiting cylinder 52, and the top of the limiting cylinder 52 contacts or nearly contacts the bottom surface of the upper bearing platform 2. This effectively restricts excessive displacement and rotation in three directions: horizontal, vertical, and tilting, preventing structural damage. After the seismic action weakens, since the lower end of the central limiting column 51 is hinged rather than rigidly fixed, the upper bearing platform 2 can be smoothly reset to the central position under the restoring force of the vertical air spring unit 3 and the horizontal negative stiffness unit 4. This avoids jamming or secondary eccentricity that may be caused by rigid limiting, thus combining the functions of safe limiting and automatic reset.

[0030] It should be noted that one end of the central limiting post 51 can also be connected to the lower support seat 1, and the other end of the central post is hinged to the upper bearing platform 2.

[0031] refer to Figure 5 In one implementation, the limiting and resetting assembly 5 also includes at least three circumferential resetting elastic elements 54 surrounding the vertical air spring unit 3. When the upper bearing platform 2 undergoes horizontal or tilting displacement relative to the lower support 1, multiple elastic elements evenly distributed around the vertical air spring unit 3 simultaneously provide restoring force from different directions, thereby effectively suppressing the residual offset and torsion of the upper bearing platform 2 in the horizontal plane. In conjunction with the hard limiting mechanism formed by the central limiting column 51 and the limiting cylinder 52, the circumferential resetting elastic elements 54 begin to flexibly assist in guiding the upper bearing platform 2 towards the central equilibrium position before the displacement reaches the hard limiting threshold, avoiding the resetting delay or eccentricity that may be caused by a single hinged limiting column. After the seismic action weakens, the circumferential resetting elastic elements 54 work together with the vertical and horizontal air springs 41 to apply a balanced resetting force from all circumferential directions, ensuring that the upper bearing platform 2 quickly, smoothly, and centrally returns to the initial equilibrium position, significantly improving the self-resetting capability and seismic isolation stability of the support under the multiple pulse action of complex oblique earthquakes.

[0032] It should be noted that the reset elastic element can be one or more of the following: helical compression spring, disc spring, ring spring, or rubber spring.

[0033] refer to Figure 5 As one implementation method, an elastic buffer layer 53 is provided on the outer wall of the central limiting column 51 and / or the inner wall of the limiting cylinder 52. When the upper bearing platform 2 experiences excessive horizontal or tilting displacement due to oblique seismic action and the central limiting column 51 comes into contact with the limiting cylinder 52, the elastic buffer layer 53 absorbs part of the impact energy through compression deformation, significantly reducing the instantaneous impact force and noise generated by rigid contact, and avoiding direct hard collision damage between the central limiting column 51 and the limiting cylinder 52. At the same time, the elastic buffer layer 53 can provide a gradual stiffness transition during the contact process, making the limiting action smoother and reducing secondary impact excitation on the superstructure. When the seismic action weakens, the rebound characteristics of the elastic buffer layer 53 can also help push the central limiting column 51 back to the center position of the limiting cylinder 52, and work together with the circumferential reset elastic element 54 to promote the smooth reset of the upper bearing platform 2. Thus, while achieving reliable mechanical limiting, the impact resistance, durability and reset smoothness of the support are improved.

[0034] It should be noted that the elastic buffer layer 53 can be made of one or more of the following: rubber, polyurethane elastomer, silicone, metal rubber, laminated rubber-metal composite layer, or foam plastic.

[0035] refer to Figure 3 As a preferred embodiment, a first ball joint 43 is provided between the horizontal air spring 41 and the connecting rod 42, and a second ball joint 44 is provided between the connecting rod 42 and the upper bearing platform 2. Both the first ball joint 43 and the second ball joint 44 include a ball seat 7, on which a ball head 6 is provided. An anti-detachment pressure cover 8 is provided on the ball seat 7 to limit the ball head 6. A wear-resistant bushing 9 is provided between the ball head 6 and the ball seat 7. The anti-detachment pressure cover 8 reliably prevents the ball head 6 from detaching from the ball seat 7, ensuring the connection safety under extreme displacement. The wear-resistant bushing 9 significantly reduces the friction and wear and rotational resistance between the ball head 6 and the ball seat 7, improves the flexibility and service life of the ball joint, and enables the horizontal negative stiffness unit 4 to maintain smooth force transmission and stable negative stiffness output in long-term reciprocating motion, thereby improving the overall seismic isolation reliability and durability of the support.

[0036] It should be noted that the wear-resistant bushing 9 can be made of one or more of the following: bronze or tin bronze, polytetrafluoroethylene (PTFE) composite material, polyoxymethylene (POM) or carbon fiber reinforced polyetheretherketone (PEEK).

[0037] refer to Figure 2As a preferred embodiment, the connecting rod 42 includes a first rod segment 421 and a second rod segment 422. A threaded adjusting sleeve 423 is provided between the first rod segment 421 and the second rod segment 422. The threaded adjusting sleeve 423 is threadedly connected to the first rod segment 421 and the second rod segment 422 to realize the length adjustment of the connecting rod 42. According to the on-site installation conditions or actual load requirements, the threaded adjusting sleeve 423 can be easily rotated to precisely adjust the total length of the connecting rod 42, thereby changing the initial compression and preload of the horizontal air spring 41, and realizing quantitative adjustment of the initial working state of the horizontal negative stiffness unit 4. At the same time, it allows for fine adjustment of the symmetry and balance between the horizontal negative stiffness units 4 as needed during the use of the support, in order to compensate for the small deformation differences caused by processing errors, installation deviations or long-term service, and ensure that the multiple horizontal air springs 41 maintain uniform force around the vertical air spring unit 3. In addition, the detachable feature of the threaded adjusting sleeve 423 also facilitates the disassembly, maintenance and component replacement of the support, improving the adaptability and maintainability of the support in different engineering scenarios.

[0038] refer to Figure 7 As one implementation method, it also includes a pressure regulating assembly 10, which includes an inflation valve 101 and an exhaust valve 102 connected to the airbags in the horizontal air spring 41 and the vertical air spring unit 3. A pressure detection element 103 is installed inside the airbag, and an tilt detection element 11 and a horizontal displacement detection element 12 are installed on the upper support platform 2 and the lower support seat 1. It also includes a control system 13, which is electrically connected to the inflation valve 101, exhaust valve 102, pressure detection element 103, horizontal displacement detection element 12, and tilt detection element 11, and is capable of real-time monitoring of the internal pressure of each airbag and the pressure of the upper support platform 2 relative to the lower support seat 1. The control system 13 automatically adjusts the inflation or deflation of the corresponding airbags based on the pressure and tilt angle signals to adjust the vertical positive stiffness and horizontal negative stiffness matching state under different load conditions or oblique seismic action, ensuring that the support is always maintained near the optimal working point of near zero stiffness. At the same time, the tilt angle detection device 11 and the horizontal displacement detection device 12 provide the control system 13 with attitude feedback of the upper bearing platform 2, enabling it to adjust the air pressure of each horizontal air spring 41 according to the asymmetric deformation, so as to actively suppress tilting and optimize the reset capability, significantly improving the adaptability and intelligence level of the support to variable load and variable seismic input.

[0039] It should be noted that the pressure detection element 103 can be a pressure sensor installed inside the air spring airbag or on the air pipeline, or it can be a digital pressure gauge or pressure switch connected to the airbag, used to collect air pressure signals in real time and transmit them to the control system 13; the tilt detection element 11 can be one or more combinations of MEMS tilt sensor, electrolyte tilt sensor, capacitive tilt sensor, inductive tilt sensor or photoelectric tilt sensor, installed on the upper support platform 2 and / or lower support 1, used to measure the tilt angle of the upper support platform 2 relative to the lower support 1 or the absolute horizontal plane; the horizontal displacement detection element 12 can be one or more combinations of wire displacement sensor, laser displacement sensor, magnetostrictive displacement sensor, eddy current displacement sensor, linear variable differential transformer (LVDT), Hall effect displacement sensor or machine vision-based non-contact displacement measurement device, installed between the lower support 1 and the upper support platform 2, used to measure the horizontal relative displacement of the upper support platform 2 relative to the lower support 1.

[0040] Example 2: This invention also discloses an installation method for a quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action. First, the lower support 1 is fixed or connected to the foundation structure, and the upper bearing platform 2 is fixed or connected to the superstructure. A vertical air spring unit 3 is installed between the lower support 1 and the upper bearing platform 2. The vertical air spring unit 3 is used to bear the vertical static load and provide vertical positive stiffness for the vibration isolation system.

[0041] Subsequently, horizontal negative stiffness units 4 are arranged around the vertical air spring unit 3. The horizontal negative stiffness unit 4 includes a fixed bracket 45, a horizontal air spring 41, and a connecting rod 42. The fixed bracket 45 is mounted on the lower support 1. One end of the horizontal air spring 41 is connected to the fixed bracket 45, and the other end is hinged to the bottom surface of the upper bearing platform 2 via the connecting rod 42. With this arrangement, the horizontal air spring 41 no longer transmits force solely as a single planar link, but allows the connecting rod 42 to oscillate spatially under oblique seismic action.

[0042] When an earthquake is transmitted to the foundation structure at an oblique angle, the superstructure causes the upper bearing platform 2 to undergo vertical, horizontal, and / or tilting displacements relative to the lower support 1. At this time, the connecting rod 42 transmits the above-mentioned combined displacements to the corresponding horizontal air spring 41 through the hinged relationship at both ends, causing the horizontal air spring 41 to undergo axial compression or rebound deformation; the vertical air spring unit 3 provides positive stiffness, and the horizontal air spring 41 forms negative stiffness through the connecting rod 42. The two match each other near the static equilibrium position, thereby forming a multi-directional quasi-zero stiffness vibration isolation state.

[0043] In a preferred embodiment, four horizontal air springs 41 are arranged in a cross shape around the vertical air spring unit 3. When an oblique earthquake is transmitted from either direction, the four horizontal air springs 41 work together to ensure that the upper bearing platform 2 obtains a more balanced negative stiffness response relative to the lower support 1 in both orthogonal directions, thus avoiding the stiffness asymmetry problem caused by traditional diagonal or unidirectional arrangements.

[0044] In a preferred embodiment, a horizontal guide assembly 46 is provided on the lower support 1. The horizontal guide assembly 46 includes a guide rail and a slider. The slider slides with the guide rail and is connected to the horizontal air spring 41 to guide the horizontal air spring 41 to extend and retract along its own axial direction. This step can reduce the lateral yaw, torsion, and additional bending stress of the horizontal air spring 41 under combined displacement, and improve the stability and repeatability of the negative stiffness output.

[0045] In a preferred embodiment, the limiting and resetting assembly 5 includes a central limiting post 51 and a limiting cylinder 52. One end of the central limiting post 51 is hinged to the lower support 1, and the other end is connected to the upper support platform 2. The bottom of the limiting cylinder 52 is connected to the lower support 1, and there is a gap between the top of the limiting cylinder 52 and the upper support platform 2. The outer diameter of the central limiting post 51 is smaller than the inner diameter of the limiting cylinder 52. Within the normal vibration isolation range, the upper support platform 2 can generate the required vertical, horizontal, and tilting displacements relative to the lower support 1. When the displacement or tilt exceeds the preset safety range, the central limiting post 51 and the limiting cylinder 52 cooperate to limit excessive deformation.

[0046] Furthermore, an elastic buffer layer 53 can be provided on the outer wall of the central limiting column 51 and / or the inner wall of the limiting cylinder 52, and at least three circumferential restoring elastic elements 54 can be provided around the vertical air spring unit 3. When limiting contact occurs, the elastic buffer layer 53 compresses and absorbs energy, forming a gradual limiting effect; when the seismic force weakens, the circumferential restoring elastic elements 54, together with the vertical air spring unit 3 and the horizontal air spring 41, provide restoring force, allowing the upper bearing platform 2 to smoothly return to its initial equilibrium position.

[0047] In a preferred embodiment, a first ball joint 43 is provided between the horizontal air spring 41 and the connecting rod 42, and a second ball joint 44 is provided between the connecting rod 42 and the upper bearing platform 2. Both the first ball joint 43 and the second ball joint 44 may include a ball seat 7, a ball head 6, an anti-detachment cap 8, and a wear-resistant bushing 9. Through the ball joint connection, the connecting rod 42 can achieve spatial swing force transmission under oblique seismic action, reducing the risks of jamming at the hinge, bending of the connecting rod, and uneven loading of the horizontal air spring.

[0048] In a preferred embodiment, the connecting rod 42 includes a first rod segment 421, a second rod segment 422, and a threaded adjusting sleeve 423. By rotating the threaded adjusting sleeve 423, the total length of the connecting rod 42 is adjusted, thereby adjusting the initial compression and preload of the corresponding horizontal air spring 41, so that each horizontal negative stiffness unit 4 maintains a symmetrical and balanced initial working state after installation.

[0049] In a preferred embodiment, a pressure regulation step is also performed. The pressure regulation assembly 10 includes an inflation valve 101, an exhaust valve 102, a pressure detection element 103, an tilt angle detection element 11, a horizontal displacement detection element 12, and a control system 13. The pressure detection element 103 collects the pressure of each air spring bladder, the tilt angle detection element 11 and the horizontal displacement detection element 12 collect the attitude and displacement of the upper support platform 2 relative to the lower support seat 1, and the control system 13 controls the inflation valve 101 and the exhaust valve 102 according to the above signals to inflate or deflate the vertical air spring unit 3 and / or the horizontal air spring 41, so as to dynamically adjust the positive and negative stiffness matching relationship and keep the support near the near-zero stiffness optimal operating point.

[0050] Through the above method, while retaining the original support structure implementation basis, the invention summarizes the inventive point into a vibration isolation control and force transmission method applicable to oblique earthquake action, so that it can reflect the synergistic relationship between installation arrangement, spatial swing force transmission, stiffness matching, limit reset and air pressure regulation in the form of method steps.

[0051] This invention discloses a continuous technical process of "arrangement-force transmission-quasi-zero stiffness formation-limiting and resetting-air pressure regulation" under oblique earthquake input. By uniformly arranging multiple horizontal air springs circumferentially in the vertical air spring unit, and making the two ends of the connecting rod spatially hinged to the horizontal air springs and the upper bearing platform respectively, vertical, horizontal and tilt displacements can be smoothly transmitted to the corresponding horizontal air springs adaptively. At the same time, the vertical air springs provide positive stiffness and the horizontal air springs provide negative stiffness, and the two work together to form a multi-directional quasi-zero stiffness characteristic, which significantly reduces the initial vibration isolation frequency and suppresses resonance transmission. With the limiting and resetting component and the air pressure regulation component, the adaptability of the support to oblique earthquakes, the smoothness of force transmission, the air pressure matching capability and the reliability of post-earthquake resetting can be improved.

[0052] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action, characterized in that, The system includes a lower support (1), an upper support platform (2) disposed above the lower support (1), a vertical air spring unit (3) disposed between the lower support (1) and the upper support platform (2), and a horizontal negative stiffness unit (4) disposed on the lower support (1) around the vertical air spring unit (3). The horizontal negative stiffness unit (4) includes a fixed bracket (45) disposed on the lower support (1), at least two horizontal air springs (41) disposed on the fixed bracket (45), and a connecting rod (42) hinged to one end of the horizontal air springs (41) away from the fixed bracket (45). The end of the connecting rod (42) away from the horizontal air springs (41) is hinged to the bottom surface of the upper support platform (2). The horizontal air springs (41) are evenly distributed around the vertical air spring unit (3).

2. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 1, characterized in that, The horizontal air springs (41) are configured as four, and the four horizontal air springs (41) are arranged in a cross shape.

3. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 1, characterized in that, A horizontal guide assembly (46) is provided on the lower support (1). The horizontal guide assembly (46) includes a guide rail provided on the lower support (1) and a slider slidably connected to the guide rail. The slider is connected to the side of the horizontal air spring (41) near the lower support (1) and the slider is connected to the side of the horizontal air spring (41) near the connecting rod (42).

4. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 1, characterized in that, It also includes a limit reset assembly (5), which includes a central limit post (51) with one end hinged to the lower support seat (1) and the other end connected to the upper support platform (2) and a limit cylinder (52) disposed around the central limit post (51). The bottom of the limit cylinder (52) is connected to the lower support seat (1), and there is a gap between the top of the limit cylinder (52) and the upper support platform (2). The outer diameter of the central limit post (51) is smaller than the inner diameter of the limit cylinder (52).

5. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 4, characterized in that, The limiting reset assembly (5) further includes at least three circumferential reset elastic elements (54) surrounding the outer periphery of the vertical air spring unit (3).

6. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 1, characterized in that, A first ball joint (43) is provided between the horizontal air spring (41) and the connecting rod (42), and a second ball joint (44) is provided between the connecting rod (42) and the upper bearing platform (2). The first ball joint (43) and the second ball joint (44) each include a ball seat (7), a ball head (6) provided on the ball seat (7), and an anti-detachment pressure cap (8) provided on the ball seat (7) to limit the ball head (6). A wear-resistant bushing (9) is provided between the ball head (6) and the ball seat (7).

7. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 1, characterized in that, The connecting rod (42) includes a first rod segment (421) and a second rod segment (422). A threaded adjusting sleeve (423) is provided between the first rod segment (421) and the second rod segment (422). The threaded adjusting sleeve (423) is threadedly connected to the first rod segment (421) and the second rod segment (422) to realize the length adjustment of the connecting rod (42).

8. The quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 1, characterized in that, It also includes a pressure regulating assembly (10), which includes an inflation valve (101) and an exhaust valve (102) communicating with the airbags in the horizontal air spring (41) and the vertical air spring unit (3), a pressure detection element (103) disposed inside the airbag, an inclination detection element (11) and a horizontal displacement detection element (12) disposed on the upper support platform (2) and the lower support seat (1), and a control system (13) electrically connected to the inflation valve (101), the exhaust valve (102), the pressure detection element (103), the horizontal displacement detection element (12) and the inclination detection element (11).

9. A method for installing a quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action, characterized in that, Includes the following steps: The lower support (1) is connected to the foundation structure, the upper bearing platform (2) is connected to the upper structure, and a vertical air spring unit (3) is set between the lower support (1) and the upper bearing platform (2) so that the vertical air spring unit (3) bears the vertical static load and provides vertical positive stiffness. A horizontal negative stiffness unit (4) is provided around the vertical air spring unit (3). The horizontal negative stiffness unit (4) includes a fixed bracket (45), at least two horizontal air springs (41) and a connecting rod (42). One end of the horizontal air spring (41) is connected to the fixed bracket (45), and the other end is hinged to the bottom surface of the upper bearing platform (2) via the connecting rod (42). Through the positive stiffness of the vertical air spring unit (3) and the horizontal negative stiffness generated by each horizontal air spring (41) via the connecting rod (42), the vibration isolation support forms a quasi-zero stiffness working state near the static equilibrium position. When the oblique seismic action is transmitted, the vertical displacement, horizontal displacement and tilting displacement of the upper bearing platform (2) relative to the lower support seat (1) are transmitted to the corresponding horizontal air spring (41) by the spatial swing of the connecting rod (42) relative to the horizontal air spring (41) and the upper bearing platform (2). When the displacement or tilt of the upper bearing platform (2) exceeds the preset range, the excessive deformation is limited by the limit reset component (5) and the upper bearing platform (2) is reset after the seismic action weakens.

10. The installation method of the quasi-zero stiffness vibration isolation bearing suitable for oblique seismic action according to claim 9, characterized in that, Install the air pressure regulating component (10), which is used to collect and regulate the air pressure of the horizontal air spring (41) and / or the vertical air spring unit (3), and collect the attitude and displacement of the upper bearing platform (2) relative to the lower support seat (1) so that the vertical positive stiffness is matched with the horizontal negative stiffness.

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