33 results about "Negative stiffness" patented technology

The application discloses a torsional negative stiffness vibration isolation device based on pre-tensioned springs and belongs to the technical field of vibration isolation devices.The vibration isolation device can normally transmit the rated torsional motion of a system, reduces the torsional dynamic stiffness of the system, lowers the natural frequency, realizes the torsional vibration isolation of shaft system components under low-frequency and ultralow-frequency bands, and has a good vibration isolation effect.Two ends of two connecting rod devices are connected in a hinged manner on an inner part and corresponding sliding blocks respectively, the two sliding blocks are limited in displacement directions through sliding grooves fixed on the inner side of an outer part, and elastic elements generate acting forces on the two sliding blocks and apply torsional moments on the inner part through the two connecting rod devices.The application introduces a negative stiffness device, reduces the torsional dynamic stiffness of a shaft system structure, lowers the natural frequency of the system in the torsional direction, and realizes the vibration isolation function under low-frequency and ultralow-frequency bands.

The present invention provides a damper having negative stiffness, comprising: a cylinder barrel, a piston rod, a piston, and a base valve. A rebound valve and a check valve are provided on the piston; a compression valve and a check valve are provided on the base valve; a valve core of the compression valve is connected to a valve core of the rebound valve by means of a spring; a limiting device for the valve core of the rebound valve is provided on the piston or the piston rod; and damping force values of the compression valve and the rebound valve are both controlled by the stroke of the piston and the acting force of the spring. During the extension of the damper, when the spring is in a compressed state, the rebound valve forms a damping force, thereby achieving a damping effect. The greater a compression stroke (compression force value) of the spring is, the greater the extension damping value of the damper is. During the compression of the damper, when the spring is in a tensioned state, the compression valve creates a damping force, thereby achieving a damping effect. The greater an extension stroke (extension force value) of the spring is, the greater the compression damping value of the damper is.

The application discloses an active quasi-zero stiffness construction method based on nonlinear characteristic digital fitting, and steps include: a quasi-zero stiffness system completes automatic zero point calibration, a force actuator unit drives a load platform to make a low-speed quasi-static scanning within a preset stroke, displacement and static force signals are synchronously collected, and a full-stroke force-displacement data set of a support assembly is constructed; then, a numerical approximation algorithm is used for fitting the data set, a digital twin mechanical model containing a high-order nonlinear term is established, and parameters are stored in a control unit. When the system is running, a high-frequency displacement detection unit collects instantaneous displacement of the load platform in real time, the control unit calls the model to calculate a current positive stiffness restoring force, generates a negative stiffness compensation instruction, drives the actuator unit to apply a compensation force to offset the positive stiffness, and makes the system present a quasi-zero stiffness characteristic within a working stroke. The method realizes quasi-zero stiffness, has advantages of no friction, parameter self-adaptation, large dynamic range and the like, and can be widely used in scenes such as spacecraft ground microgravity simulation and high-precision constant force assembly.

The application belongs to the field of vibration isolation and noise reduction equipment, and discloses a variable load magnetic gas type three-way high static low dynamic stiffness vibration isolator and a use method. The variable load magnetic gas type three-way high static low dynamic stiffness vibration isolator comprises a supporting assembly, a positive stiffness assembly and a negative stiffness assembly. The positive stiffness assembly provides static bearing capacity and is composed of an air spring and a linear spring, and the negative stiffness assembly is composed of a magnetic group and a supporting structure thereof, and the purpose of reducing dynamic stiffness is achieved by being connected in parallel with the positive stiffness assembly. The variable load magnetic gas type three-way high static low dynamic stiffness vibration isolator has large static stiffness and small dynamic stiffness, three-way forces generated by the movement between the inner magnetic group and the outer magnetic resistance are used to offset a part of three-way forces generated by the air bag, the function of reducing stiffness is realized, the variable load magnetic gas type three-way high static low dynamic stiffness vibration isolator can adapt to the change of load working conditions, has a wider application scene and better three-way low-frequency vibration isolation performance, a wide vibration isolation frequency band, and stable working performance.

The application discloses a bidirectional horizontal quasi-zero stiffness vibration isolator and relates to the technical field of vibration reduction devices. The bidirectional horizontal quasi-zero stiffness vibration isolator comprises a bottom plate, a top plate, an intermediate plate, a vibration isolation mechanism and the like. The bottom plate is used for being mounted on a vibration source. The top plate is arranged above the bottom plate and is used for bearing a load. The intermediate plate is arranged between the bottom plate and the top plate. The top plate is configured to be movable along a first horizontal direction relative to the intermediate plate. The intermediate plate is configured to be movable along a second horizontal direction relative to the bottom plate. The second horizontal direction is orthogonal to the first horizontal direction. The vibration isolation mechanism is arranged between the bottom plate and the top plate and is used for making the equivalent dynamic stiffness in the first horizontal direction and the second horizontal direction approach to zero near a balance position. The vibration isolation mechanism comprises a positive stiffness element and a negative stiffness mechanism. The bidirectional horizontal quasi-zero stiffness vibration isolator can bear the load stably by means of the positive stiffness element in a static state. The bidirectional horizontal quasi-zero stiffness vibration isolator exhibits extremely low dynamic stiffness in a dynamic slight vibration state, so that low-frequency vibration can be effectively isolated.

The application discloses a kind of magnetic control negative stiffness adjusting methods, comprising the following steps: two magneto-rheological elastomer units are respectively arranged, and rigid member is connected between two magneto-rheological elastomer units;Pre-compression force perpendicular to two magneto-rheological elastomer units is applied to rigid member, so that deformation is generated in the direction of two magneto-rheological elastomer unit connecting line respectively and pre-shear force is generated, while negative stiffness force is generated in the direction perpendicular to two magneto-rheological elastomer unit connecting line;The same adjustable magnetic field of size is arranged on two magneto-rheological elastomer units respectively, and the size of magnetic field is controlled, so that the negative stiffness force value generated by two magneto-rheological elastomers can be controlled;The application can solve the current magneto-rheological elastomer vibration isolation mechanism stiffness value is higher and can only be positively regulated, it is difficult to carry out stiffness negative regulation, and then it is difficult to simultaneously exist for the equipment of direct disturbance and external disturbance, realize the technical problem of efficient vibration isolation and stability.

This invention relates to the field of vibration isolation device technology, specifically to a parallel vibration isolation device based on a cosine-shaped curved beam with positive and negative stiffness, comprising: a laminated rubber bearing, including an upper connecting plate and a lower connecting plate, with a rubber layer and a steel plate layer between the upper and lower connecting plates, and located at the center of the upper and lower connecting plates; a fixing structure, disposed on the upper and lower connecting plates and arranged in parallel on the outer periphery of the rubber layer and the steel plate layer; a laminated cosine curved beam, having multiple pieces, disposed on the fixing structure, with a joint on the laminated cosine curved beam, the joint being connected to the upper connecting plate; and a limiting post, disposed on the lower connecting plate, the limiting post being located at the bottom of the laminated cosine curved beam. This parallel vibration isolation device based on a cosine-shaped curved beam has a simple structure, and by arranging the laminated cosine curved beam in parallel on the outer periphery of the laminated rubber bearing, it improves the vertical vibration isolation capability without affecting the horizontal vibration isolation performance.

This invention discloses a quasi-zero stiffness vibration isolator, relating to the field of vibration isolation technology. A positive stiffness mechanism is disposed between a platform and a base, supporting the platform under external load and applying a restoring force opposite to and positively correlated with the platform's displacement direction when the platform displaces. A negative stiffness mechanism includes a mover and several electro-permanent magnet units, fixedly mounted on the base. One end of the mover is fixedly connected to the platform. The positive stiffness mechanism, the mover, and all the electro-permanent magnet units are symmetrically arranged about a symmetrical centerline, which is collinear with the direction of the external load force. The other end of the mover has a gap with each electro-permanent magnet unit in a direction perpendicular to the symmetrical centerline. The electro-permanent magnet units generate a magnetic field and apply a magnetic force to the mover in the same direction as the mover's displacement. Through the parallel connection of the positive and negative stiffness mechanisms, the vibration isolator achieves quasi-zero stiffness characteristics near its equilibrium position, thereby achieving low-frequency vibration isolation. This device can improve the reliability of the vibration isolator and extend its service life.

The application discloses a preloaded adjustable torsional quasi-zero stiffness vibration isolator for a cantilever structure and relates to the technical field of vibration isolators, which comprises a torsional quasi-zero stiffness module, a cantilever structure and a cantilever structure support base fixedly connected with the cantilever structure. The torsional quasi-zero stiffness module comprises a positive stiffness component and a negative stiffness component exhibiting negative stiffness characteristics. The positive stiffness component comprises a fixed outer ring, a positive stiffness part connecting inner ring and a preformed compliant curved beam for connecting the fixed outer ring and the positive stiffness part connecting inner ring. The negative stiffness component comprises an adjustable outer ring, a negative stiffness part connecting inner ring and a compression buckling beam for connecting the adjustable outer ring and the negative stiffness part connecting inner ring. The positive stiffness part connecting inner ring and the negative stiffness part connecting inner ring are fixedly connected through a connecting piece. The fixed outer ring and the adjustable outer ring are connected through a movable connecting piece, the rotation angle adjustment of the fixed outer ring and the adjustable outer ring is realized, and the quasi-zero stiffness interval of the system can adapt to different load working conditions.

This invention relates to the field of low-frequency vibration control technology, and particularly to an adjustable quasi-zero stiffness vibration isolator with an optimal equilibrium position indicator. The isolator includes an upper pressure plate, a lower pressure plate, an upper connecting plate, a lower connecting plate, and an intermediate connecting plate. A positive stiffness mechanism is provided between the upper and lower connecting plates, and a negative stiffness mechanism is provided between the upper and intermediate connecting plates. The negative stiffness mechanism includes a vertical rod, a connecting rod, a horizontal rod, and a disc spring. An optimal equilibrium indicator is provided between the horizontal rod and the support guide frame. A height adjustment mechanism is provided between the intermediate and lower connecting plates. When the load deviates from the design value, the distance between the intermediate and lower connecting plates is changed by the height adjustment mechanism, and the isolator is adjusted to the optimal static equilibrium position by relying on the positioning block's insertion into the positioning hole. This prevents the negative stiffness mechanism from transmitting vertical force, achieving quasi-zero stiffness characteristics. This invention has a compact structure, intuitive and reliable adjustment, and can stably maintain excellent low-frequency vibration isolation performance under variable load conditions.

The present application relates to a kind of Halbach electromagnetic quasi-zero stiffness vibration isolation platform, including storage platform, bottom plate and be arranged between the positive stiffness component, negative stiffness component and active electromagnetic component.Positive stiffness component includes telescopic guide rod, spring and adjusting washer arranged on the bottom plate, one end of spring is connected with storage platform, the other end is connected with adjusting washer;Negative stiffness component includes fixed housing, fixed magnet array and moving magnet array;Active electromagnetic component includes metal coil.Fixed magnet array is vertically arranged by a plurality of first fixed magnet and second fixed magnet according to Halbach array, moving magnet array is vertically arranged by a plurality of moving magnets, and the sum of vertical positive stiffness of spring is equal to the maximum negative stiffness of moving magnet array.Compared with prior art, the present application effectively improves the vibration isolation performance of vibration isolation platform, and can be widely applied to the occasion with higher vibration isolation requirement.

The present application relates to hydrophone demodulation technical field, disclose a kind of hydrophone demodulation interferometer with load flexible adjustment vibration isolation technology, comprising: interferometer module, shell and low-frequency vibration isolator, interferometer module is encapsulated in shell, the bottom of shell is fixedly connected with the top of low-frequency vibration isolator;Low-frequency vibration isolator includes base platform, two vibration isolation units, horizontal guide rod, load platform, two torsional magnetic negative stiffness mechanisms and two telescopic hinge structures;Two vibration isolation units are symmetrically arranged on the two sides of base platform, etc.;The hydrophone demodulation interferometer with load flexible adjustment vibration isolation technology can make low-frequency vibration isolator present quasi-zero stiffness and load flexible adjustable characteristics by configuring appropriate structural parameters and adjusting the pre-tightening force of vertical spring and the angle between connecting rod and horizontal direction of vertical fixing ring and horizontal fixing ring, so as to realize the effective isolation between hydrophone demodulation interferometer and environmental noise.

The utility model discloses a kind of quasi-zero stiffness vibration isolator based on gap elastic limiting and connecting rod coupling, belong to the technical field of vibration isolator.The quasi-zero stiffness vibration isolator includes: connecting rod mechanism, linear spring restraint component, vibration isolation plate and mounting base;Connecting rod mechanism is four equal-length connecting rods;Linear spring restraint component includes connecting spring, support spring and limit spring;Bar piece AB, AC, A'B', A'C' are connected by hinged joint connection;AA' two ends are connected by the connecting spring of horizontal placement;CC' two ends are fixed on mounting base, BB' two ends are fixedly hinged on vibration isolation plate;BC, B'C' end are connected by vertical support spring;Limit spring EF E end is fixed on mounting base, F end and the inside surface of vibration isolation plate interval preset distance.Vibration isolator realizes low force transfer rate and displacement transfer rate under low-frequency excitation, connecting rod mechanism adjusts the negative stiffness of system, limit spring provides positive stiffness compensation when large displacement, expands vibration isolation bandwidth, and enhances the adaptability and stability of vibration isolator.

The utility model discloses a kind of quasi-zero stiffness vibration isolator and vibration isolation system based on inertial capacity and connecting rod coupling belong to vibration isolator technical field.The quasi-zero stiffness vibration isolator includes: connecting rod structure, spring assembly, inertial container, vibration isolation plate and mounting base;Connecting rod structure includes four equal-length connecting rods;Spring assembly includes connecting spring and two support springs;Bar piece AB, AC, A'B', A'C' are connected by hinged joint connection;AA' two ends are connected by the connecting spring and inertial container of horizontal parallel placement;CC' two ends are fixed on mounting base, BB' two ends are fixedly hinged on vibration isolation plate;BC, B'C' end are connected by a vertical support spring;Support spring provides positive stiffness in vertical direction, connecting spring provides negative stiffness, inertial container is amplified by inertia equivalent mass of vibration isolation target, to reduce resonance frequency.Vibration isolator realizes low force transfer rate and displacement transfer rate under low-frequency excitation, enhances the adaptability and stability of vibration isolator.

The application discloses a negative stiffness local resonance flexible photovoltaic support damping pull rod device and relates to the technical field of photovoltaic equipment.The flexible photovoltaic support damping pull rod device takes an equilateral triangle steel plate as a core bearing and force transmission component, combines photovoltaic module cables, windproof cables and a damping system in the same base, realizes directional collection and accurate transmission of multidimensional vibration, avoids damping failure caused by vibration dispersion and attenuation, and simultaneously has strong geometric stability of the triangle structure, can improve the overall rigidity and deformation resistance of the flexible photovoltaic support without significantly increasing the self weight of the support, balances the lightweight and structural rigidity requirements of the flexible support, reduces the vibration amplitude from the basic level, simultaneously suppresses the transverse swing, longitudinal vibration and torsional swing of the photovoltaic module cable, effectively reduces the node fatigue damage, cable relaxation and structural deformation risk under the reciprocating action of wind load, and significantly improves the operation safety and structural durability of the flexible photovoltaic support in a strong wind area.

This invention discloses a low-frequency wide-amplitude vibration isolator based on stacked origami in parallel, relating to the field of vibration reduction and isolation technology. The key technical features are: a base plate with fixed plates vertically positioned at both opposite edges; a guide rail at the bottom of the base plate, with its two ends abutting against the inner walls of the fixed plates on both sides; a slider on the outer side of the guide rail, slidably connected to the track end of the guide rail; a connecting plate vertically positioned at the top of the slider; a bearing platform at the end of the connecting plate away from the slider; and multistable origami cells on both sides of the connecting plate. In this invention, when the base plate is subjected to displacement excitation, the two symmetrically arranged isomorphic multistable origami cells, in parallel assembly, generate a wide-amplitude linear negative stiffness, which can cancel out the linear positive stiffness of the spring. Compared to the single-point zero-stiffness design of existing quasi-zero stiffness vibration isolators, this vibration isolator can achieve wide-amplitude zero stiffness, enabling low-frequency vibration isolation even at large amplitudes.

The application discloses a torsional quasi-zero stiffness vibration absorber and relates to the technical field of vibration control, which is used for being installed on a vibration receiving shaft to suppress torsional vibration of the shaft and comprises a bearing ring, a bearing ring, a positive stiffness mechanism, a negative stiffness mechanism and an inertial mass block. The bearing ring is fixedly installed on the vibration receiving shaft. The bearing ring is coaxially arranged with the bearing ring and is connected with the positive stiffness mechanism and the negative stiffness mechanism between the bearing ring and the bearing ring. The positive stiffness mechanism is used for providing positive stiffness elastic restoring force, and the negative stiffness mechanism is used for providing negative stiffness effect. The inertial mass block is detachably installed on the bearing ring and is used for providing rotational inertia. Therefore, the problems that the traditional linear vibration absorber cannot simultaneously consider low-frequency vibration suppression performance and static bearing capacity, the structure is not compact enough and the wide-frequency low-frequency torsional vibration cannot be effectively suppressed can be solved.

The application discloses a stiffness and damping adjustable vibration isolator and relates to the technical field of vibration isolation devices.The vibration isolator comprises a load platform, a foundation platform, a damping device, a positive stiffness component and a negative stiffness component.The foundation platform is arranged below the load platform, the stiffness component and the damping device are arranged between the foundation platform and the load platform, two working ends of the damping device, the positive stiffness component and the negative stiffness component are respectively connected with the load platform and the foundation platform, the stiffness of the positive stiffness component and the negative stiffness component is adjustable, the damping device can change the damping by changing the current size of the wire on the damping device, the vibration isolator can adjust the positive stiffness, the negative stiffness and the damping, and has a wide application range.

The application provides a passive quasi-zero stiffness vibration isolation unit and track system for a floating slab track, wherein the vibration isolation unit comprises a shell with a support disc, and an internal positive stiffness mechanism, a negative stiffness mechanism and a mechanical coupling structure; the positive stiffness mechanism comprises a mechanical spring and a positive stiffness gas spring arranged in parallel, the mechanical spring provides a main static load path independent of gas pressure and generates a restoring force that increases with displacement when compressed; the negative stiffness mechanism comprises a plurality of negative stiffness gas springs uniformly distributed around the positive stiffness mechanism; the mechanical coupling structure is used to connect the positive stiffness mechanism and the negative stiffness mechanism, and the negative stiffness gas springs are stretched under the driving of the mechanical coupling structure to generate a restoring force that decreases with displacement; the two compensate for each other within a predetermined working displacement, so that the vibration isolation unit presents a quasi-zero stiffness characteristic near the equilibrium position. The application has a simple, stable and reliable structure, is a passive design, can maintain high static load capacity, and effectively attenuates low-frequency and ultra-low-frequency vibrations.

This invention relates to an integrated negative stiffness friction damping device and its application, belonging to the field of vibration control technology. It includes an external frame comprising a horizontal top frame, a bottom frame, and four vertical support rods at the corners. A vertical fixed track is installed at the center line of the top connecting plate, with one end of a sliding track embedded in the fixed track and the other end fixed to the bottom connecting plate. The two ends of the horizontal support rods are connected to the fixed track and the top frame, respectively. An L-shaped connector is connected at one end to the sliding friction plate and at the other end to the bottom connecting plate. A friction assembly is symmetrically arranged around the fixed track. The two ends of each friction assembly are bolted to the top and bottom frames, respectively. Double-ear connectors are provided on the inner side of the friction assembly and the outer side of the fixed track for hinged connection with nitrogen springs. This invention employs a parallel design and integration principle, providing significant negative stiffness while improving energy dissipation capacity and significantly reducing structural displacement, acceleration, and internal force response.

The application provides a quasi-zero stiffness vibration isolator based on a bistable composite hybrid laminate, which comprises a base, a groove being formed in the base, a connecting block being arranged in the groove, a positive stiffness structure, the positive stiffness structure comprising a pair of left-right symmetrical and spaced thin shells, the lower ends of the two thin shells being fixedly connected to the groove bottom, and the upper ends being fixedly connected to the connecting block, the middle parts of the two thin shells being respectively protruded to form a pair of convex parts with curvature in directions away from each other, and a first cavity being formed between the two thin shells, a negative stiffness structure, the negative stiffness structure comprising a plurality of bistable composite hybrid laminates, the laminates on the same side being symmetrically and spacedly arranged, a second cavity being formed, and the length directions of the laminates being parallel to each other, the surfaces of the laminates being curved, the laminates being fixed to the connecting block, the two ends of the laminates being fixedly connected to the groove walls in opposite directions, and a support being further fixed to the connecting block for bearing external force, and the application can replace a complex spring mechanism to construct a quasi-zero stiffness system.

A magnetic ring type high static low dynamic stiffness vibration isolator capable of adapting to various working conditions and a use method thereof belong to the field of vibration isolation and noise reduction equipment and are composed of a support assembly, a permanent magnet positive stiffness assembly, a disc spring negative stiffness assembly and a bearing mechanism. The support assembly is a hollow cylindrical structure and can shield the influence of a magnetic field on the external environment. The permanent magnet positive and negative stiffness assemblies respectively provide positive and negative stiffness for the vibration isolator, wherein the relative movement between the inner and outer magnetic groups in the positive stiffness assembly generates a magnetic force to provide a vertical bearing capacity. The bearing mechanism supports the vibration-isolated object on the object table. The vibration isolator can be applied to various vibration working conditions, has the effects of reducing the vibration amplitude from the base to the vibration-isolated object and providing a supporting action, and the vibration-isolated object needs to be placed horizontally or fixed on the object table during use. The vibration isolator can adapt to changes in the load working condition by adjusting the relative position between the magnets, has good low-frequency and ultra-low-frequency vibration isolation effect, a wide vibration isolation frequency band and stable working performance.

The application discloses a large-stroke double-working-condition self-adaptive quasi-zero stiffness vibration isolator and a semi-active control method thereof, and belongs to the technical field of vibration control. In order to solve the problem that the existing vibration isolator is difficult to adapt to different load weights and simultaneously maintain the vibration isolation performance under a large stroke because of fixed parameters, the application provides a vibration isolator which comprises a base unit, a bearing unit, and a negative stiffness mechanism and an adjustable nonlinear positive stiffness mechanism which are arranged in parallel between the base unit and the bearing unit. The adjustable nonlinear positive stiffness mechanism is configured to be capable of being semi-actively adjusted, so as to compensate for the nonlinear distortion of the negative stiffness mechanism under a large displacement in a semi-active manner, so that the system can dynamically maintain a quasi-zero stiffness state under different load working conditions, and simultaneously meet the large-stroke vibration isolation demand. The application is suitable for occasions such as precision instruments and optical platforms which have high requirements for low-frequency and large-amplitude vibration isolation, and especially has the capability of adapting to single load change or two specific load working conditions.

The application belongs to the technical field of vibration control, and particularly relates to a main structure displacement amplification type tuned negative stiffness inertial mass dynamic vibration absorbing system. The system comprises a bottom plate, a core transmission member, a positive stiffness spring mechanism, a gear amplification mechanism, a negative stiffness device, an inertial mass device driven to rotate by the movement of the core transmission member to generate an equivalent tuned mass, and an eddy current damping device. The gear amplification mechanism amplifies the initial displacement input by the external main structure, overcoming the defects of the traditional shock absorber, such as difficulty in triggering and insufficient work under low frequency or slight vibration; not only the natural frequency of the coupled structure is reduced by the negative stiffness effect to broaden the vibration reduction frequency band, but also more energy is dissipated in unit time and a huge equivalent tuned mass is generated, so that the destructive large displacement of the base isolation layer in strong earthquakes is extremely efficiently inhibited without significantly increasing the structure acceleration, and the seismic safety of the building is comprehensively improved.

This invention relates to the field of vibration control technology, and more particularly to a cable multimodal control device and method based on a passive adjustable stiffness-damper. The device includes a mechanical damper and an adjustable equivalent stiffness device. The adjustable equivalent stiffness device comprises a preloaded spring-type negative stiffness mechanism, a lever-type positive stiffness mechanism, and a power mechanism. The lever-type positive stiffness mechanism changes the equivalent stiffness generated by the series connection of the preloaded spring-type negative stiffness mechanism and the lever-type positive stiffness mechanism by changing the lever ratio. The power mechanism is installed between the cable and the ground to sense the cable's vibration, generate relative motion with it, and drive the lever-type positive stiffness mechanism, thereby changing the lever ratio of the lever-type positive stiffness mechanism. Through a purely mechanical structure, this invention provides a novel solution for multimodal control of cables targeting nodal modes, with a wide range of applications. Compared to existing active / semi-active methods that change the dynamic parameters of the damper, it eliminates the need for external power supply.