Tuned mass damper based on nitrogen spring-convex surface mechanism and shock isolation method

Abstract

The invention relates to a tuned mass damper based on a nitrogen spring-convex surface mechanism and a shock isolation method. The tuned mass damper comprises a ball screw flywheel structure, a convex surface spring structure and a nitrogen spring structure, the convex spring structure comprises a first spring, a center rod and a friction convex surface, the nitrogen spring structure comprises a sleeve and a nitrogen spring, the sleeve is fixed on the main body structure, the center rod extends into the sleeve, the exposed part of the center rod is connected with the ball screw flywheel structure through the first spring, and the friction convex surface is arranged on the extending part; the nitrogen spring is fixed in the sleeve and comprises a roller, a cylinder and a piston rod, the cylinder is filled with nitrogen, a piston of the piston rod is arranged in the cylinder, a rod body of the piston rod extends out of the cylinder, and the extending end of the rod body is in contact with the friction convex surface through the roller. Compared with the prior art, the adjustable negative stiffness, inerter mass efficiency improvement, damping energy consumption and improvement of the vibration isolation effect and the frequency adjusting capacity are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of civil engineering and relates to a tuned mass damper based on a nitrogen spring-convex surface mechanism and a seismic isolation method. Background Art

[0002] Tuned mass damper is a passive vibration absorption technology in engineering structure vibration control. It is commonly used in the fields of civil engineering and mechanical engineering. A mass block, a tuned stiffness unit and a damping unit are set to form a tuned mass damper. By setting the natural frequency of the tuned mass damper close to the natural frequency of the controlled main structure, resonant energy absorption and vibration reduction control are achieved. However, existing passive tuned mass dampers have problems such as the predicted error of the natural frequency of the controlled main structure, the machining error of the tuned stiffness unit and the complexity of the external excitation frequency component. Under the detuned state and low-frequency excitation conditions, the vibration reduction control performance of the tuned mass damper deteriorates, and it is often necessary to add a larger tuned mass (large inertia mass) and a longer tuned mass swing stroke to achieve optimal tuned vibration absorption.

[0003] Patent CN112160438A discloses a magnetic screw-type eddy current damper with negative stiffness nonlinear energy well, including a spring mass system, an inertial mass system, an eddy current damping system, a negative stiffness system and a support system; by introducing an inertial mass amplification mechanism, the physical weight of the damper is reduced, so as to improve the mass ratio of the device while reducing the net extension of the spring of the device controlling the low-frequency structure; by introducing a negative stiffness nonlinear energy well element, resonant energy capture within a wide frequency range is achieved. Although the patent has a negative stiffness mechanism and an inertial mechanism, the negative stiffness mechanism of the patent can only achieve a limited negative stiffness effect that gradually decreases with increasing displacement. The effective negative stiffness coefficient achieved based on the permanent magnet mechanism is limited and cannot provide a multi-level adjustable negative stiffness effect. The effective working frequency range is insufficient, and it is difficult to meet the frequency correction of the tuned mass damper in the detuned state.

[0004] Patent CN111139730A discloses a low-frequency vertical tuned mass damper with a negative stiffness nonlinear energy well. The patent uses the nonlinear attraction between the moving permanent magnet group and the fixed permanent magnet group to make the device have the characteristics of a negative stiffness nonlinear energy well. The ball screw inertia mechanism is used to amplify the equivalent vibration mass of the tuned mass damper, and while improving the damping effect of the tuned mass damper, the problem of excessive net elongation of the spring of the ultra-low frequency vertical tuned mass damper is solved. The advantages of the nonlinear energy well and the tuned mass damper are integrated to broaden the control frequency band of the tuned mass damper. However, this patent is similar to the above patents, using electromagnetic elements to realize the negative stiffness mechanism. The negative stiffness that can be provided will decrease with the increase of displacement, and it cannot provide customizable and enhanced negative stiffness, nor can it provide stable bearing capacity and meet large deformation conditions.

[0005] Patent CN112343393A discloses an amplified negative stiffness friction damping wall, including a top steel plate, a bottom friction plate, a side plate, a nitrogen spring nesting device, a pre-stressed nitrogen spring, a bare rod, a linear bearing, a pressure transmission plate, a track wheel, a secondary lever system, a rotating rod, a friction plate, and a friction plate; the pre-stressed nitrogen spring elastic force is amplified by the secondary lever system, and the amplified elastic force is squeezed by the rotating rod to squeeze the friction plate, and the friction plate embedded at the bottom of the friction plate generates friction with the bottom friction plate. When the damping wall produces relative displacement, the rotating rod generates a negative stiffness force along the horizontal component, that is, a negative stiffness damping is formed. However, this patent only relies on the pre-stressed nitrogen spring to achieve the negative stiffness effect, and the multi-stage lever it uses to achieve the direction adjustment of the negative stiffness control force and the force amplitude amplification is still a single type of negative stiffness realization mechanism. In addition, when this patent is used as a damping wall to achieve additional damping and shock absorption control of building structures, its physical size is large and it needs to be arranged on the bottom floor of the building.

[0006] Patent CN111942095A discloses a semi-active suspension for a new energy vehicle coupled with a magnetic suspension spring and an eddy current damper, including an eddy current damping generating structure, a magnetic suspension spring structure and a magnetorheological fluid; the weight of the vehicle body is supported by the attraction between the mobile permanent magnet and the coil permanent magnet fixed in the lower working cylinder; the suspension can control the current in the coil permanent magnet and the excitation coil according to the real-time feedback of the acceleration sensor installed in the piston, change the magnitude of the force between the coil permanent magnet and the mobile permanent magnet and the viscosity characteristics of the magnetorheological fluid, so as to achieve adjustable suspension stiffness and damping; when the car is driving on a road with a bad road environment, the induced current generated in the coil permanent magnet can be recovered through the external circuit. However, the patent controls the current change stiffness of the coil permanent magnet and the excitation coil through a complex system of control circuits, and cannot provide compact and efficient negative stiffness coefficients and control forces. Summary of the invention

[0007] The purpose of the present invention is to overcome at least one defect of the above-mentioned prior art and to provide a tuned mass damper and seismic isolation method based on a nitrogen spring-convex mechanism. The present invention realizes adjustable negative stiffness, inertia mass enhancement, damping energy consumption, and improves vibration isolation effect and frequency regulation capability.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] One of the technical solutions of the present invention is to provide a tuned mass damper based on a nitrogen spring-convex mechanism, the tuned mass damper comprises a ball screw flywheel structure, a convex spring structure and a nitrogen spring structure, the main structure is provided with a nitrogen spring structure, and the nitrogen spring structure is connected to the ball screw flywheel structure through the convex spring structure;

[0010] The convex spring structure includes a first spring, a center rod and a friction convex surface. The nitrogen spring structure includes a sleeve and a nitrogen spring. The sleeve is fixed on the main structure. The center rod extends into the sleeve. The exposed part of the center rod is connected to the ball screw flywheel structure through the first spring. The extended part is provided with a friction convex surface. The nitrogen spring is fixed in the sleeve. The nitrogen spring includes a roller, a cylinder and a piston rod. The cylinder is filled with nitrogen. A piston of the piston rod is provided in the cylinder. The rod body of the piston rod extends out of the cylinder. The extended end of the rod body contacts the friction convex surface through the roller. The convex structure of the nitrogen spring and the friction convex surface constitutes a nitrogen spring-convex mechanism composite negative stiffness unit.

[0011] As a preferred technical solution, the material of the center rod is selected from one or more of steel, aluminum alloy, and copper alloy, with excellent processing performance, and the material of the friction convex surface is selected from one or more of steel, cast iron, and copper alloy, with excellent wear resistance.

[0012] As a preferred technical solution, at least one pair of friction convex surfaces is provided on the portion into which the center rod extends.

[0013] As a preferred technical solution, at least one pair of nitrogen springs is fixed in the sleeve.

[0014] When the main structure vibrates, that is, produces vertical displacement, the ball screw flywheel structure undergoes vertical displacement, and the center rod and the friction convex surface are driven to displace by the first spring. At this time, the convex spring structure and the nitrogen spring structure undergo vertical relative displacement, and the nitrogen spring-convex mechanism composite negative stiffness unit plays a role;

[0015] The central rod and the friction convex surface undergo vertical relative displacement with the nitrogen spring next to it. Due to the pre-compression design of the nitrogen spring and the convex structure design of the friction convex surface, the nitrogen spring next to it provides an auxiliary motion force in the same direction of displacement to the convex spring structure, thereby assisting and amplifying the movement of the tuned mass damper.

[0016] Furthermore, the nitrogen spring adopts a multi-stage nitrogen spring, which includes a roller and at least two stages of cylinders and piston rods. The cylinders are filled with nitrogen, and the pistons of the piston rods of the same stage are arranged in the cylinders of the same stage. The cylinders of the latter stage are arranged in the piston rods of the former stage. The pistons and rod bodies of the piston rods of the other stages except the last stage are all confined in the cylinders of the same stage. The piston of the piston rod of the last stage is confined in the cylinder of the last stage, and the rod body extends out of the cylinder of the last stage. The extended end of the rod body contacts the friction convex surface through the roller.

[0017] Furthermore, a hole is provided on the piston, and the cylinder of the same level keeps the front and rear spaces divided by the piston of the piston rod of the same level connected through the hole, and the cylinder of the next level is connected with the cylinder of the previous level through the hole when the pistons of the piston rods of the front and rear levels are not in contact, and after the piston rod of the previous level moves until the rod body of the piston rod of the previous level contacts the cylinder of the previous level, nitrogen enters the inner cavity of the piston rod through the hole to form the cylinder of the next level, thereby constituting a multi-stage locking nitrogen spring;

[0018] By utilizing the design that the cross-sectional area of ​​the rod body of the piston rod is smaller than that of the piston, and utilizing the difference in cross-sectional area between the rod body of the rear-stage piston rod and the piston being different from that of the front-stage piston rod, different stages of the multi-stage nitrogen spring can provide adjustable preload for the convex structure, further optimizing the stiffness performance, and the movement process of the convex spring structure is divided into two stages: in the initial stage, the preload of the multi-stage nitrogen spring is relatively large, and the friction convex surface moves synchronously with the center rod without generating relative displacement; as the vertical relative displacement between the convex spring structure and the nitrogen spring structure increases, the preload gradually decreases, and the friction convex surface moves relative to the center rod, generating Coulomb friction on the contact surface and dissipating energy.

[0019] Furthermore, the ball screw flywheel structure is connected to the main structure through a convex spring structure and a nitrogen spring structure connected in series and then connected in parallel with a spring. The spring provides positive stiffness. The force of the nitrogen spring acting on the friction convex surface changes continuously with the vertical relative displacement of the convex spring structure and the nitrogen spring structure. The nitrogen spring-convex mechanism composite negative stiffness unit provides multi-stage nonlinear negative stiffness related to the displacement. The stiffness of the tuned mass damper changes with the displacement, thereby achieving the characteristics of high static stiffness and low dynamic stiffness.

[0020] As a preferred technical solution, in a static state, the roller is located at the highest point of the friction convex surface. At this time, the nitrogen spring only provides horizontal preload, ensuring that the tuned mass damper has sufficient load-bearing capacity in a static state to prevent excessive deformation; in a dynamic state, the tuned mass damper significantly reduces the natural frequency and the displacement transmission rate by reducing the equivalent dynamic stiffness.

[0021] Since the stiffness of the nitrogen spring-convex mechanism composite negative stiffness unit changes with displacement, the tuned mass damper can realize the frequency adjustment function, thereby adapting to the changing vibration environment and improving the performance stability and adaptability.

[0022] As a preferred technical solution, the ball screw flywheel structure and the main structure are connected in series through a convex spring structure and a nitrogen spring structure, and then at least one pair of springs are connected in parallel for vertical connection.

[0023] As a preferred technical solution, the springs are all linear springs, and the stiffness of the linear springs is a certain value. The mechanical properties of the negative stiffness part of the component can be more easily adjusted by selecting linear springs with different stiffnesses.

[0024] Furthermore, the ball screw flywheel structure includes a flywheel, a ball nut and a threaded screw. The flywheel is coaxially fixedly connected to the radial outer side of the ball nut. The flywheel and the ball nut are both mounted on the threaded screw. When the main structure vibrates, that is, vertical displacement occurs, the ball screw flywheel structure undergoes vertical displacement, converting the vertical displacement into high-speed rotational motion of the flywheel, thereby generating inertia mass enhancement.

[0025] Furthermore, the ball screw flywheel structure also includes a limit block, the flywheel is embedded in the limit block, and the threaded screw extends into the limit block, so that the flywheel is limited to no vertical displacement relative to the limit block and can only undergo high-speed rotational movement. A screw limit plate is provided on the protruding end of the threaded screw, and a spring limit plate is provided on the exposed part of the center rod. The screw limit plate is connected to the spring limit plate via a first spring, and the limit plate serves as an installation position for the first spring while limiting the vertical relative displacement of the ball screw flywheel structure and the main structure.

[0026] As a preferred technical solution, the first spring is sleeved on the exposed portion of the center rod, and the two ends of the first spring are vertically fixedly connected to the lead screw limit plate and the spring limit plate respectively.

[0027] As a preferred technical solution, a limiting cylinder is arranged under the limiting block, and the limiting cylinder extends into the sleeve, and the first spring, center rod, screw limiting plate and spring limiting plate move in the limiting cylinder to limit the horizontal movement of these components.

[0028] Furthermore, a permanent magnet disc is arranged in the limit block, and the flywheel includes a conductor flywheel gear piece and a non-conductor flywheel gear piece arranged at intervals. The conductor flywheel gear piece and the non-conductor flywheel gear piece rotate at high speed, cutting the magnetic flux lines generated by the permanent magnet disc, forming an eddy current effect to consume energy.

[0029] As a preferred technical solution, the material of the conductive flywheel gear piece is selected from one or more of steel, aluminum alloy, and copper alloy, and has good conductivity; the material of the non-conductive flywheel gear piece is selected from one or more of rubber, ceramic, and wood, and has good electrical insulation performance.

[0030] Furthermore, a group of permanent magnet disks are arranged in the limit block, namely a first permanent magnet disk and a second permanent magnet disk, the first permanent magnet disk and the second permanent magnet disk are respectively arranged on both sides of the flywheel, the N-stage and S-stage of the first permanent magnet disk and the second permanent magnet disk are oriented in the same direction, the first permanent magnet disk and the second permanent magnet disk generate vertical magnetic flux lines passing through the flywheel, and the rotation of the flywheel will produce a change in magnetic flux and generate eddy current damping to achieve an energy dissipation effect.

[0031] Furthermore, the permanent magnet disc includes permanent magnet disc teeth and non-conductor disc teeth that are arranged at intervals. When the first permanent magnet disc and the second permanent magnet disc are arranged relative to each other, since the permanent magnet disc teeth and non-conductor disc teeth are arranged alternately and there are vertical intervals between a group of permanent magnet discs, their magnetic field characteristics are affected by the arrangement structure, thereby forming an intermittent magnetic field distribution in the vertical direction.

[0032] As an optimal technical solution, the material of the permanent magnet disc tooth piece is selected from one or more of ferrite magnet, neodymium iron boron, aluminum nickel cobalt, and has good ferromagnetic properties. The material of the non-conductor disc tooth piece is selected from one or more of rubber, ceramic, and wood, and has good magnetic insulation properties.

[0033] As a preferred technical solution, two ends of the spring are respectively vertically fixedly connected to the limit block and the main structure.

[0034] The tuned mass damper utilizes the synergistic effect of inertia, negative stiffness and friction energy dissipation to significantly improve the vibration isolation effect and frequency regulation capability.

[0035] One of the technical solutions of the present invention is to provide a seismic isolation method based on a nitrogen spring-convex mechanism, which uses the tuned mass damper to isolate the main structure, and the method includes the following steps:

[0036] The convex spring structure has two processes. The first process: in the initial stage, the preload provided by the multi-stage nitrogen spring next to the center rod is large enough, and the friction convex surface next to the center rod moves together with the center rod under the action of the preload of the multi-stage nitrogen spring next to it, without generating relative displacement; the second process: as the vertical relative displacement between the convex spring structure and the nitrogen spring structure gradually increases, the preload provided by the multi-stage nitrogen spring next to it gradually decreases, and the friction convex surface next to it moves relative to the center rod, and Coulomb friction is generated on the contact surface and damping energy is consumed;

[0037] There are two stages in the movement of the nitrogen spring structure. The first stage: the cylinder and piston rod of the previous stage form the nitrogen spring of the previous stage, and the cross-sectional area of ​​the rod body of the piston rod is smaller than the cross-sectional area of ​​the piston, thereby generating a pressure difference to provide pre-stress for the convex spring structure; the second stage: as the piston rod of the previous stage moves to the end point, the inner cavity of the piston rod of the previous stage serves as the cylinder of the next stage, and nitrogen enters the cylinder of the next stage through the hole. The cylinder and piston rod of the next stage form the nitrogen spring of the next stage, and the cross-sectional area of ​​the rod body of the piston rod is also smaller than the cross-sectional area of ​​the piston, so as to provide pre-stress for the convex spring structure. The difference between the cross-sectional area of ​​the rod body of the piston rod of the next stage and the piston is different from the difference between the cross-sectional area of ​​the rod body of the piston rod of the previous stage and the piston, so different designable pre-stress effects can be provided for the convex spring structure;

[0038] The center rod and the multi-stage nitrogen spring and friction convex surface next to it are connected to the ball screw flywheel structure through the first spring. The ball screw flywheel structure converts the vertical displacement of the threaded screw into the rotation of the ball nut, thereby driving the flywheel to rotate, generating an inertia effect. The conductor flywheel gear pieces and the non-conductor flywheel gear pieces of the flywheel rotate to cut the magnetic flux lines generated by the first permanent magnet disc and the second permanent magnet disc, forming an eddy current effect to damp and dissipate energy.

[0039] The ball screw flywheel structure is connected to the main structure through a convex spring structure and a nitrogen spring structure. When the main structure vibrates, that is, a vertical displacement is generated, a relative displacement occurs between the ball screw flywheel structure and the main structure. The spring provides linear positive stiffness, and the nitrogen spring-convex mechanism composite negative stiffness unit composed of the convex structure of the nitrogen spring and the friction convex surface provides multi-stage nonlinear negative stiffness related to the displacement, thereby realizing flexible adjustment of the stiffness, and then realizing flexible adjustment of the vibration isolation frequency domain, making the application range of the tuned mass damper wider.

[0040] As a preferred technical solution, the difference in cross-sectional area between the rod body and the piston of the latter stage piston rod is greater than the difference in cross-sectional area between the rod body and the piston of the former stage piston rod, thereby providing a designable enhanced preload effect for the convex spring structure.

[0041] As a preferred technical solution, the difference in cross-sectional area between the rod body and the piston of the latter stage piston rod is smaller than the difference in cross-sectional area between the rod body and the piston of the former stage piston rod, thereby providing a designable reduced pre-stress effect for the convex spring structure.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The present invention utilizes the convex structure of the multi-stage nitrogen spring composite friction convex surface to achieve multi-stage adjustable negative stiffness mechanical characteristics; utilizes the pre-loaded nitrogen spring and the convex structure dual mechanism in parallel to provide a compact and efficient negative stiffness realization mechanism, and significantly enhances the reliability of the tuned mass damper of the nitrogen spring-convex mechanism; further utilizes multiple parallel-arranged positive stiffness tuning springs below the ball screw flywheel structure to achieve static load bearing and dynamic frequency modulation functions, and utilizes the ball screw flywheel structure to achieve inertia mass efficiency enhancement and eddy current damping limit functions; utilizes the nitrogen spring-convex mechanism composite negative stiffness unit to be connected in series with the tuning spring and the ball screw flywheel structure, and then connects the tuning spring in parallel to form an adaptive tuned mass damping system that meets low-frequency tuning and frequency adjustment requirements;

[0044] (2) The present invention can achieve a multi-stage preload effect of a multi-stage nitrogen spring by designing the difference between the area of ​​multiple piston rods and pistons of the multi-stage nitrogen spring; a two-stage motion process is achieved by designing the center rod and the friction convex surfaces on both sides of the convex spring structure, providing a multi-stage nonlinear negative stiffness design related to displacement, and the Coulomb friction formed by the relative movement of the center rod and the friction convex surfaces on both sides in the second stage further enhances the energy dissipation capacity;

[0045] (3) The nitrogen spring-convex mechanism of the present invention has a multi-stage nonlinear negative stiffness design related to displacement. By connecting in parallel with multiple positive stiffness tuning springs, the positive stiffness, negative stiffness or quasi-zero stiffness of the device and its size can be adjusted in real time, further realizing flexible adjustment of structural stiffness, absorption and dissipation of vibration energy, and at the same time increasing the vibration isolation frequency domain, realizing seismic isolation and frequency adjustment capabilities within a wider frequency domain;

[0046] (4) The ball screw flywheel structure of the present invention converts the vertical linear motion of the threaded screw into the rotational motion of the flywheel, and introduces the inertia principle to reduce the physical weight while improving the mass ratio of the device. At the same time, the rotation of the conductor flywheel gear of the flywheel cuts the magnetic flux lines generated by a group of permanent magnet disks, forming an eddy current effect; and the series-connected nitrogen spring-convex mechanism further promotes the vertical linear motion and rotational motion of the ball screw flywheel structure, thereby improving the energy consumption efficiency of the generated eddy current damping;

[0047] (5) The eddy current damping effect formed by the flywheel rotating and cutting the magnetic flux lines and the Coulomb friction damping effect formed by the relative displacement between the friction convex surface and the center rod of the present invention realize the integration of multiple damping effects;

[0048] (6) The present invention belongs to dynamic vibration absorption technology, and can provide low-frequency, mass-enhanced tuned vibration absorbers and efficiency-enhanced seismic isolation layers and their additional inertial vibration absorbers, which occupy a small space and are more compact in design and can be applied to a variety of application scenarios. The present invention adopts a dual passive mechanical adjustment design of pre-stressed nitrogen springs and convex structures, without relying on complex active control systems, which significantly improves the stability and operational reliability of the system, and does not require any external input of electrical energy, and can operate normally in any environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the front cross-sectional structure of a tuned mass damper based on a nitrogen spring-convex mechanism in an embodiment of the present invention;

[0050] Figure 2 Schematic diagram of the top view of the flywheel in an embodiment of the present invention;

[0051] Figure 3 Schematic diagram of the top view of the permanent magnet disk in an embodiment of the present invention;

[0052] Figure 4 Schematic diagram of the front cross-sectional structure of a multi-stage nitrogen spring in an embodiment of the present invention.

[0053] Description of the markings in the figure:

[0054] 1—ball screw flywheel structure, 2—convex spring structure, 3—nitrogen spring structure, 5—main structure;

[0055] 11—first permanent magnet disc, 12—flywheel, 13—second permanent magnet disc, 14—ball nut, 15—threaded screw;

[0056] 111—permanent magnet disc gear piece, 112—non-conductor disc gear piece;

[0057] 121—conductor flywheel gear, 122—non-conductor flywheel gear;

[0058] 21—first spring, 22—center rod, 23—first friction convex surface, 24—second friction convex surface;

[0059] 31 - first multi-stage nitrogen spring, 32 - sleeve, 33 - second multi-stage nitrogen spring;

[0060] 311 - first cylinder, 312 - first piston rod, 313 - second piston rod, 314 - second cylinder, 315 - roller;

[0061] 41 - second spring, 42 - third spring, 43 - fourth spring, 44 - fifth spring. DETAILED DESCRIPTION

[0062] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0063] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are used to describe common objects, which only refer to different instances of the same object, and are not intended to imply that the objects described in this way must adopt a given order, whether in time, space, order or any other way.

[0064] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0065] Example:

[0066] A tuned mass damper based on a nitrogen spring-convex mechanism, such as Figure 1 and Figure 4 As shown, it includes a ball screw flywheel structure 1, a convex spring structure 2 and a nitrogen spring structure 3. The nitrogen spring structure 3 is arranged on the main structure 5, and the nitrogen spring structure 3 is connected to the ball screw flywheel structure 1 through the convex spring structure 2;

[0067] The convex spring structure 2 includes a first spring 21, a center rod 22 and a friction convex surface. The nitrogen spring structure 3 includes a sleeve 32 and a nitrogen spring. The sleeve 32 is fixed on the main structure 5. The center rod 22 extends into the sleeve 32. The exposed portion of the center rod 22 is connected to the ball screw flywheel structure 1 through the first spring 21. The extended portion is provided with a friction convex surface. The nitrogen spring is fixed in the sleeve 32. The nitrogen spring includes a roller 315, a cylinder and a piston rod. The cylinder is filled with nitrogen. A piston of the piston rod is provided in the cylinder. The rod body of the piston rod extends out of the cylinder. The extended end of the rod body contacts the friction convex surface through the roller 315. The convex structure of the nitrogen spring and the friction convex surface constitutes a nitrogen spring-convex mechanism composite negative stiffness unit.

[0068] The material of the center rod 22 is selected from one or more of steel, aluminum alloy, and copper alloy, and has excellent processing performance. In this embodiment, steel is preferred;

[0069] The material of the friction convex surface is selected from one or more of steel, cast iron, and copper alloy, and has excellent wear resistance. In this embodiment, steel is preferred;

[0070] At least one pair of friction convex surfaces is provided on the portion where the center rod 22 extends. In this embodiment, a pair of two friction convex surfaces are provided horizontally opposite to each other on both sides of the portion where the center rod 22 extends, namely a first friction convex surface 23 and a second friction convex surface 24.

[0071] The nitrogen spring is a multi-stage nitrogen spring, and at least one pair of multi-stage nitrogen springs is fixed in the sleeve 32. In this embodiment, a pair of two multi-stage nitrogen springs are horizontally fixed at both ends of the sleeve 32, which are a first multi-stage nitrogen spring 31 and a second multi-stage nitrogen spring 32.

[0072] When the main structure 5 vibrates, i.e., produces vertical displacement, the ball screw flywheel structure 1 undergoes vertical displacement, and the first spring 21 drives the center rod 22, the first friction convex surface 23 and the second friction convex surface 24 to displace. At this time, the convex spring structure 2 and the nitrogen spring structure 3 undergo vertical relative displacement, and the nitrogen spring-convex mechanism composite negative stiffness unit plays a role;

[0073] The center rod 22, the first friction convex surface 23 and the second friction convex surface 24 are vertically relatively displaced with the first multi-stage nitrogen spring 31 and the second multi-stage nitrogen spring 32 on both sides. Due to the pre-compression design of the multi-stage nitrogen spring and the convex structure design of the friction convex surface, the first multi-stage nitrogen spring 31 and the second multi-stage nitrogen spring 32 on both sides provide auxiliary motion force in the same displacement direction to the convex spring structure 2, thereby assisting and amplifying the movement of the tuned mass damper.

[0074] The multi-stage nitrogen spring includes a roller 315 and at least two-stage cylinders and piston rods. The cylinders are filled with nitrogen. The pistons of the piston rods of the same stage are arranged in the cylinders of the same stage. The cylinders of the next stage are arranged in the piston rods of the previous stage. The pistons and rod bodies of the piston rods of the other stages except the last stage are all confined in the cylinders of the same stage. The piston of the piston rod of the last stage is confined in the cylinder of the last stage. The rod body extends out of the cylinder of the last stage, and the extended end of the rod body contacts the friction convex surface through the roller 315.

[0075] In this embodiment, the multi-stage nitrogen spring includes a roller 315 and two-stage cylinders and piston rods, which are respectively a first cylinder 311 and a first piston rod 312, a second cylinder 314 and a second piston rod 313. Nitrogen is filled in the first cylinder 311 and the second cylinder 314. The piston of the first piston rod 312 is arranged in the first cylinder 311, the second cylinder 314 is arranged in the first piston rod 311, and the piston of the second piston rod 313 is arranged in the second cylinder 314. The piston and rod body of the first piston rod 312 are both limited in the first cylinder 311, the piston of the second piston rod 313 is limited in the second cylinder 314, the rod body extends out of the second cylinder 314, and the extended end of the rod body contacts the friction convex surface through the roller 315;

[0076] In this embodiment, the extended end of the rod body of the second piston rod 313 of the first multi-stage nitrogen spring 31 contacts the first friction convex surface 23 through the roller 315, so that the first multi-stage nitrogen spring 31 is connected to the first friction convex surface 23, and the extended end of the rod body of the second piston rod 313 of the second multi-stage nitrogen spring 32 contacts the second friction convex surface 24 through the roller 315, so that the second multi-stage nitrogen spring 32 is connected to the second friction convex surface 24;

[0077] A hole is provided on the piston, and the cylinder of the same level keeps the front and rear spaces divided by the piston of the piston rod of the same level connected through the hole. The cylinder of the next level is connected with the cylinder of the previous level through the hole when the pistons of the piston rods of the front and rear levels are not in contact. After the piston rod of the previous level moves until the rod body of the piston rod of the previous level contacts the cylinder of the previous level, nitrogen enters the inner cavity of the piston rod through the hole to form the cylinder of the next level, thus forming a multi-stage locking nitrogen spring;

[0078] In this embodiment, a hole is provided on the piston of the first piston rod 312, and the first cylinder 311 keeps the front and rear spaces divided by the piston of the first piston rod 312 connected through the hole. A hole is provided on the piston of the second piston rod 313, and the second cylinder 314 keeps the front and rear spaces divided by the piston of the second piston rod 313 connected through the hole. The second cylinder 314 is connected to the first cylinder 311 through the hole when the pistons of the first piston rod 312 and the second piston rod 313 are not in contact. After the first piston rod 312 moves until the rod body of the first piston rod 312 contacts the first cylinder 311, nitrogen enters the inner cavity of the first piston rod 312 through the hole to form the second cylinder 314, forming a two-stage locking nitrogen spring;

[0079] By utilizing the design that the cross-sectional area of ​​the rod body of the piston rod is smaller than that of the piston, and utilizing the fact that the difference in cross-sectional area between the rod body of the rear-stage piston rod and the piston is different from that of the front-stage piston rod, different stages of the multi-stage nitrogen spring can provide adjustable pre-stress for the convex structure, further optimizing the stiffness performance. The movement process of the convex spring structure 2 is divided into two stages: in the initial stage, the pre-stress of the multi-stage nitrogen springs on both sides is relatively large, and the friction convex surface and the center rod 22 move synchronously without generating relative displacement; as the vertical relative displacement between the convex spring structure 2 and the nitrogen spring structure 3 increases, the pre-stress gradually decreases, and the friction convex surface and the center rod 22 move relative to each other, and the contact surface generates Coulomb friction and dissipates energy;

[0080] The ball screw flywheel structure 1 and the main structure 5 are connected in series through the convex spring structure 2 and the nitrogen spring structure 3, and then connected in parallel with the spring. The spring provides positive stiffness. The force of the nitrogen spring acting on the friction convex surface changes continuously with the vertical relative displacement of the convex spring structure 2 and the nitrogen spring structure 3. The nitrogen spring-convex mechanism composite negative stiffness unit provides multi-stage nonlinear negative stiffness related to the displacement. The stiffness of the tuned mass damper changes with the displacement, thereby achieving the characteristics of high static stiffness and low dynamic stiffness.

[0081] In the static state, the roller 315 is located at the highest point of the friction convex surface. At this time, the nitrogen spring only provides horizontal preload to ensure that the tuned mass damper has sufficient load-bearing capacity in the static state to prevent excessive deformation. In the dynamic state, the tuned mass damper significantly reduces the natural frequency and displacement transmission rate by reducing the equivalent dynamic stiffness.

[0082] In addition, since the stiffness of the nitrogen spring-convex mechanism composite negative stiffness unit changes with displacement, the tuned mass damper can realize the frequency adjustment function, thereby adapting to the changing vibration environment and improving performance stability and adaptability;

[0083] The ball screw flywheel structure 1 and the main structure 5 are connected in series through the convex spring structure 2 and the nitrogen spring structure 3, and then at least one pair of springs are connected in parallel for vertical connection. In this embodiment, the ball screw flywheel structure 1 and the main structure 5 are connected in series through the convex spring structure 2 and the nitrogen spring structure 3, and then two pairs of four springs are connected in parallel for vertical connection, which are the second spring 41, the third spring 42, the fourth spring 43 and the fifth spring 44;

[0084] The above springs, i.e., the first spring 21, the second spring 41, the third spring 42, the fourth spring 43 and the fifth spring 44 are all linear springs, and the stiffness of the linear springs is a certain value. It is easier to adjust the mechanical properties of the negative stiffness component by selecting linear springs with different stiffnesses.

[0085] The ball screw flywheel structure 1 comprises a flywheel 12, a ball nut 14 and a threaded screw 15. The flywheel 12 is coaxially fixedly connected to the radial outer side of the ball nut 14. The flywheel 12 and the ball nut 14 are both sleeved on the threaded screw 15. When the main structure 5 vibrates, that is, vertical displacement occurs, the ball screw flywheel structure 1 undergoes vertical displacement, converting the vertical displacement into high-speed rotational motion of the flywheel 12, thereby generating inertia mass efficiency.

[0086] The ball screw flywheel structure 1 also includes a limit block, the flywheel 12 is embedded in the limit block, the threaded screw 15 extends into the limit block, and the flywheel 12 is limited to not produce vertical displacement relative to the limit block, and can only undergo high-speed rotational motion. A screw limit piece is provided on the extended end of the threaded screw 15, and a spring limit piece is provided on the exposed portion of the center rod 22. The screw limit piece is connected to the spring limit piece through a first spring 21. The limit piece serves as a mounting position for the first spring 21, and limits the vertical relative displacement of the ball screw flywheel structure 1 and the main structure 5.

[0087] The first spring 21 is sleeved on the exposed portion of the center rod 22, and the two ends of the first spring 21 are respectively vertically fixedly connected to the lead screw limit plate and the spring limit plate;

[0088] A limiting cylinder is arranged under the limiting block, and the limiting cylinder extends into the sleeve 32. The first spring 21, the center rod 22, the screw limiting piece and the spring limiting piece move in the limiting cylinder to limit the horizontal movement of these components.

[0089] like Figure 2 As shown, a permanent magnet disc is arranged in the limit block, and the flywheel 12 includes a conductor flywheel gear piece 121 and a non-conductor flywheel gear piece 122 arranged at intervals. The conductor flywheel gear piece 121 and the non-conductor flywheel gear piece 122 rotate at a high speed, cutting the magnetic flux lines generated by the permanent magnet disc, forming an eddy current effect to consume energy;

[0090] The material of the conductor flywheel gear piece 121 is selected from one or more of steel, aluminum alloy, and copper alloy, and has good electrical conductivity. In this embodiment, steel is preferred;

[0091] The material of the non-conductive flywheel gear piece 122 is selected from one or more of rubber, ceramic, and wood, and has good electrical insulation performance. In this embodiment, rubber is preferred;

[0092] A group of permanent magnet discs are arranged in the limit block, namely, a first permanent magnet disc 11 and a second permanent magnet disc 13. The first permanent magnet disc 11 and the second permanent magnet disc 13 are arranged on both sides of the flywheel 12 respectively. The N-level and S-level directions of the first permanent magnet disc 11 and the second permanent magnet disc 13 are the same. The first permanent magnet disc 11 and the second permanent magnet disc 13 generate vertical magnetic flux lines passing through the flywheel 12. At this time, the rotation of the flywheel 12 will produce a change in magnetic flux and generate eddy current damping to achieve an energy dissipation effect.

[0093] In this embodiment, the first permanent magnet disc 11 is arranged on the upper side of the flywheel 12, the second permanent magnet disc 13 is arranged on the lower side of the flywheel 12, the threaded screw 15 extends into the second permanent magnet disc 13, and the N-levels of the first permanent magnet disc 11 and the second permanent magnet disc 13 are both facing upward, and the S-levels are both facing downward;

[0094] like Figure 3 As shown, the permanent magnet disc includes permanent magnet disc tooth pieces 111 and non-conductor disc tooth pieces 112 that are arranged at intervals. When the first permanent magnet disc 11 and the second permanent magnet disc 13 are arranged relatively, since the permanent magnet disc tooth pieces 111 and the non-conductor disc tooth pieces 112 are arranged alternately and there is a vertical interval between a group of permanent magnet discs, the magnetic field characteristics thereof are affected by the arrangement structure, thereby forming an interval magnetic field distribution in the vertical direction;

[0095] The material of the permanent magnet disc tooth piece 111 is selected from one or more of ferrite magnet, neodymium iron boron, aluminum nickel cobalt, and has good ferromagnetic properties. In this embodiment, ferrite magnet is preferably used;

[0096] The material of the non-conductive disc tooth piece 112 is selected from one or more of rubber, ceramic, and wood, and has good magnetic insulation performance. In this embodiment, rubber is preferred;

[0097] In this embodiment, the two ends of the second spring 41, the third spring 42, the fourth spring 43 and the fifth spring 44 are respectively vertically fixedly connected to the limit block and the main structure 5;

[0098] The tuned mass damper utilizes the synergistic effect of inertia, negative stiffness and friction energy dissipation to significantly improve vibration isolation and frequency regulation capabilities.

[0099] A seismic isolation method based on a nitrogen spring-convex mechanism uses the above-mentioned tuned mass damper to isolate the main structure, and the specific steps are as follows:

[0100] The convex spring structure 2 has two processes. The first process: in the initial stage, the preload provided by the first multi-stage nitrogen spring 31 and the second multi-stage nitrogen spring 32 on both sides of the center rod 22 is large enough. The first friction convex surface 23 and the second friction convex surface 24 on both sides of the center rod 22 move together with the center rod 22 under the action of the preload of the multi-stage nitrogen springs on both sides, and no relative displacement occurs. The second process: as the vertical relative displacement between the convex spring structure 2 and the nitrogen spring structure 3 gradually increases, the preload provided by the first multi-stage nitrogen spring 31 and the second multi-stage nitrogen spring 32 on both sides gradually decreases, and the first friction convex surface 23 and the second friction convex surface 24 on both sides move relative to the center rod 22, and the contact surface generates Coulomb friction and performs damping energy consumption.

[0101] The movement of the nitrogen spring structure 3 has two stages. The first stage: the first cylinder 311 and the first piston rod 312 form a first-stage nitrogen spring. The cross-sectional area of ​​the piston rod is smaller than the cross-sectional area of ​​the piston, thereby generating a pressure difference to provide pre-stress for the convex spring structure 2. The second stage: as the first piston rod 312 moves to the right end point, the inner cavity of the first piston rod 312 serves as the second cylinder 314. Nitrogen enters the second cylinder 314 through the hole. The second cylinder 314 and the second piston rod 313 form a second-stage nitrogen spring. Similarly, the cross-sectional area of ​​the piston rod is smaller than the cross-sectional area of ​​the piston, thereby providing pre-stress for the convex spring structure 2. The difference between the cross-sectional area of ​​the second piston rod 313 and the piston is greater than the difference between the cross-sectional area of ​​the first piston rod 312 and the piston. Therefore, a designable enhanced pre-stress effect can be provided for the convex spring structure 2.

[0102] The center rod 22 and the first multi-stage nitrogen spring 31 and the second multi-stage nitrogen spring 32 on both sides, the first friction convex surface 23 and the second friction convex surface 24 are connected to the ball screw flywheel structure 1 through the first spring 21. The ball screw flywheel structure 1 converts the vertical displacement of the threaded screw 15 into the rotation of the ball nut 14, thereby driving the flywheel 12 to rotate, generating an inertia effect. The conductor flywheel gear piece 121 and the non-conductor flywheel gear piece 122 of the flywheel 12 rotate to cut the magnetic flux lines generated by the first permanent magnet disc 11 and the second permanent magnet disc 13, forming an eddy current effect for damping and energy dissipation.

[0103] The ball screw flywheel structure 1 is connected to the main structure 5 through the convex spring structure 2 and the nitrogen spring structure 3, the second spring 41, the third spring 42, the fourth spring 43, and the fifth spring 44. When the main structure 5 vibrates, that is, a vertical displacement occurs, a relative displacement occurs between the ball screw flywheel structure 1 and the main structure 5. The second spring 41, the third spring 42, the fourth spring 43, and the fifth spring 44 provide linear positive stiffness, and the nitrogen spring-convex mechanism composite negative stiffness unit composed of the convex structure of the nitrogen spring and the friction convex surface provides multi-stage nonlinear negative stiffness related to the displacement, thereby realizing flexible adjustment of the stiffness, and then realizing flexible adjustment of the vibration isolation frequency domain, so that the application range of the tuned mass damper is wider.

[0104] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A tuned mass damper based on a nitrogen spring-convex mechanism, characterized in that: The tuned mass damper comprises a ball screw flywheel structure (1), a convex spring structure (2) and a nitrogen spring structure (3); the nitrogen spring structure (3) is arranged on a main body structure (5); and the nitrogen spring structure (3) is connected to the ball screw flywheel structure (1) via the convex spring structure (2); The convex spring structure (2) comprises a first spring (21), a center rod (22) and a friction convex surface; the nitrogen spring structure (3) comprises a sleeve (32) and a nitrogen spring; the sleeve (32) is fixed to the main structure (5); the center rod (22) extends into the sleeve (32); the exposed portion of the center rod (22) is connected to the ball screw flywheel structure (1) via the first spring (21); the extended portion is provided with a friction convex surface; the nitrogen spring is fixed in the sleeve (32); the nitrogen spring comprises a roller (315), a cylinder and a piston rod; the cylinder is filled with nitrogen; a piston of the piston rod is provided in the cylinder; the rod body of the piston rod extends out of the cylinder; the extended end of the rod body contacts the friction convex surface via the roller (315).

2. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 1, characterized in that: The nitrogen spring adopts a multi-stage nitrogen spring, which comprises a roller (315) and at least two-stage cylinders and piston rods. Nitrogen is filled in the cylinders. The pistons of the piston rods of the same stage are arranged in the cylinders of the same stage. The cylinders of the next stage are arranged in the piston rods of the previous stage. The pistons and rod bodies of the piston rods of the other stages except the last stage are all confined in the cylinders of the same stage. The piston of the piston rod of the last stage is confined in the cylinder of the last stage. The rod body extends out of the cylinder of the last stage, and the extended end of the rod body contacts the friction convex surface through the roller (315).

3. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 2, characterized in that: The piston is provided with a hole, and the cylinder of the same level keeps the front and rear spaces divided by the piston of the piston rod of the same level connected through the hole, and the cylinder of the next level is connected with the cylinder of the previous level through the hole when the pistons of the piston rods of the front and rear levels are not in contact; The difference between the cross-sectional area of ​​the rod body and the piston of the latter stage piston rod is different from that of the former stage piston rod.

4. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 1, characterized in that: The ball screw flywheel structure (1) and the main body structure (5) are connected in series via a convex spring structure (2) and a nitrogen spring structure (3), and then connected via a parallel spring.

5. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 1, characterized in that: The ball screw flywheel structure (1) comprises a flywheel (12), a ball nut (14) and a threaded screw (15); the flywheel (12) is coaxially fixedly connected to the radial outer side of the ball nut (14); and the flywheel (12) and the ball nut (14) are both sleeved on the threaded screw (15).

6. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 5, characterized in that: The ball screw flywheel structure (1) also includes a limit block, the flywheel (12) is embedded in the limit block, the threaded screw (15) extends into the limit block, a screw limit plate is arranged on the extended end of the threaded screw (15), a spring limit plate is arranged on the exposed part of the center rod (22), and the screw limit plate is connected to the spring limit plate via a first spring (21).

7. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 6, characterized in that: A permanent magnet disc is arranged in the limit block, and the flywheel (12) comprises a conductor flywheel gear piece (121) and a non-conductor flywheel gear piece (122) arranged at intervals, and the conductor flywheel gear piece (121) and the non-conductor flywheel gear piece (122) rotate to cut the magnetic flux lines generated by the permanent magnet disc.

8. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 7, characterized in that: A group of permanent magnet discs are arranged in the limit block, namely a first permanent magnet disc (11) and a second permanent magnet disc (13); the first permanent magnet disc (11) and the second permanent magnet disc (13) are arranged on both sides of the flywheel (12), respectively; and the N-stage and S-stage directions of the first permanent magnet disc (11) and the second permanent magnet disc (13) are the same.

9. A tuned mass damper based on a nitrogen spring-convex mechanism according to claim 7, characterized in that: The permanent magnet disc comprises permanent magnet disc teeth (111) and non-conductor disc teeth (112) which are arranged at intervals.

10. A seismic isolation method based on a nitrogen spring-convex mechanism, characterized in that: The method uses the tuned mass damper according to any one of claims 1 to 9 to perform seismic isolation of the main structure, and the method comprises the following steps: The convex spring structure (2) has two processes. The first process: in the initial stage, the preload provided by the multi-stage nitrogen spring next to the center rod (22) is large, and the friction convex surface next to the center rod (22) moves together with the center rod (22) under the action of the preload of the multi-stage nitrogen spring next to it, without generating relative displacement; the second process: as the vertical relative displacement between the convex spring structure (2) and the nitrogen spring structure (3) increases, the preload provided by the multi-stage nitrogen spring next to it decreases, and the friction convex surface next to it moves relative to the center rod (22), and the contact surface generates Coulomb friction and performs damping energy dissipation; The movement of the nitrogen spring structure (3) has two stages. In the first stage, the cylinder and piston rod of the previous stage form the nitrogen spring of the previous stage. The cross-sectional area of ​​the piston rod is smaller than the cross-sectional area of ​​the piston, thereby generating a pressure difference, thereby providing pre-stress for the convex spring structure (2). In the second stage, as the piston rod of the previous stage moves to the end point, the inner cavity of the piston rod of the previous stage serves as the cylinder of the next stage. Nitrogen enters the cylinder of the next stage through the hole. The cylinder and piston rod of the next stage form the nitrogen spring of the next stage. Similarly, the cross-sectional area of ​​the piston rod is smaller than the cross-sectional area of ​​the piston, thereby providing pre-stress for the convex spring structure (2). The difference between the cross-sectional area of ​​the piston rod of the next stage and the piston is different from the difference between the cross-sectional area of ​​the piston rod of the previous stage and the piston, thereby providing different pre-stress effects for the convex spring structure (2). The center rod (22) and the adjacent multi-stage nitrogen spring and friction convex surface are connected to the ball screw flywheel structure (1) through the first spring (21). The ball screw flywheel structure (1) converts the vertical displacement of the threaded screw (15) into the rotation of the ball nut (14), thereby driving the flywheel (12) to rotate, generating an inertia effect. The conductive flywheel gear (121) and the non-conductive flywheel gear (122) of the flywheel (12) rotate to cut the magnetic flux lines generated by the first permanent magnet disc (11) and the second permanent magnet disc (13), forming an eddy current effect to damp and dissipate energy. The ball screw flywheel structure (1) is connected to the main structure (5) through a convex spring structure (2) and a nitrogen spring structure (3). When the main structure (5) vibrates, i.e., generates vertical displacement, relative displacement occurs between the ball screw flywheel structure (1) and the main structure (5). The spring provides linear positive stiffness, and the nitrogen spring-convex mechanism composite negative stiffness unit composed of a convex structure of a nitrogen spring and a friction convex surface provides multi-level nonlinear negative stiffness related to the displacement, thereby realizing flexible adjustment of stiffness, and further realizing flexible adjustment of the vibration isolation frequency domain.

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