A vibration isolator with adjustable stiffness and damping

Abstract

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.

Description

Technical Field

[0001] This invention relates to the field of vibration isolation devices, and in particular to a vibration isolator with adjustable stiffness and damping. Background Technology

[0002] For precision equipment such as sonar, radar, and satellite imaging systems, vibration can significantly impact their surveying performance and imaging quality. To reduce the impact of vibration on equipment operation, engineers have proposed various vibration isolation device designs. Traditional passive vibration isolation devices consist of mass-spring-damping, and are widely used due to their simple principle, high reliability, and low cost. However, since there is no external energy intervention, once the structural design is completed, the stiffness, damping, and other components affecting the vibration isolation effect cannot be adjusted or changed after manufacturing. The system performance parameters are fixed, thus limiting its adaptability to different interference excitations. Moreover, the inherent contradiction between the vibration transmissibility at low frequencies and the vibration attenuation rate at high frequencies means that passive vibration isolation devices alone cannot meet the vibration isolation requirements of precision equipment. Compared to passive vibration isolation technology, active vibration isolation, due to the input of external energy, can not only isolate high-frequency vibrations but also improve the low-frequency vibration isolation effect. However, the use of sensors, actuators, and control algorithms increases the complexity of the system structure, requires a large amount of external energy to drive the actuators, and places higher demands on the system's power consumption and the efficiency and reliability of the algorithm.

[0003] Semi-active vibration isolation lies between passive and active vibration isolation, combining the high reliability of passive isolation with the strong adaptability of active isolation. It requires only a small amount of external energy, namely changing the spring stiffness or damping coefficient, to alter the overall vibration isolation performance of the system. Chinese patent CN114607722A discloses a semi-active vibration isolation platform and assembly method for micro-vibrations in optical remote sensing satellites. The isolation device includes upper and lower platform bodies, a flow pipe, magnetorheological fluid, a magnetic induction coil, end caps, a mounting frame, flanges, and connectors. This isolation platform utilizes an optimal fuzzy control method, providing controllable damping force through the magnetorheological fluid to achieve micro-vibration suppression. However, this device requires the use of magnetorheological fluid to achieve damping changes and must consider sealing, thus limiting its application environment. Furthermore, the device lacks a structure capable of altering the positive and negative stiffness between the upper and lower platform bodies, making it impossible to control the influence of stiffness on vibration isolation. Therefore, there is an urgent need for a vibration isolator with a wide range of applications that can control the positive and negative stiffness between platforms. Summary of the Invention

[0004] The purpose of this invention is to provide a vibration isolator with adjustable stiffness and damping to solve the problems existing in the prior art. It can achieve adjustment of positive stiffness, negative stiffness and damping, and has a wide range of applications.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A vibration isolator with adjustable stiffness and damping includes a load platform, a base platform, a damping device, a positive stiffness component, and a negative stiffness component. The base platform is disposed below the load platform. The positive stiffness component, the negative stiffness component, and the damping device are all disposed between the base platform and the load platform. The two working ends of each of the damping device, the positive stiffness component, and the negative stiffness component are respectively connected to the load platform and the base platform. The stiffness of the positive stiffness component and the negative stiffness component is adjustable. The damping of the damping device can be changed by changing the magnitude of the current in the conductor on the damping device.

[0007] Preferably, the positive stiffness component includes a vertically arranged positive stiffness spring and a screw. At least a portion of the screw extends into the positive stiffness spring and is threadedly connected to it. The end of the positive stiffness spring away from the screw is a first working end, which is fixedly connected to the load platform. The end of the screw away from the positive stiffness spring is a second working end, which is rotatably connected to the base platform. A limiting member is fixedly connected to the positive stiffness spring, and a limiting part is fixedly connected to the base platform. The limiting part can limit the horizontal position of the limiting member. The screw is fixed in the vertical direction and can rotate relative to the connection between the screw and the base platform, thereby changing the degree of screw insertion into the positive stiffness spring. The positive stiffness spring can move up or down as the degree of screw insertion into the positive stiffness spring changes, thereby causing the load platform to move up or down.

[0008] Preferably, the negative stiffness component includes a magnet mechanism and a drive mechanism. The magnet mechanism includes an upper magnet, a main magnet, and a lower magnet with opposite magnetic poles facing each other. The upper magnet and the lower magnet form a third working end, and the main magnet forms a fourth working end. The fourth working end is fixedly connected to the load platform. The drive mechanism is fixedly connected to the positive stiffness spring. The drive mechanism has two working parts that can move in the vertical direction. The upper magnet and the lower magnet are arranged sequentially from top to bottom and are fixedly connected to one of the working parts respectively. That is, the third working end is connected to the base platform through the drive mechanism and the positive stiffness component. The main magnet is disposed between the upper magnet and the lower magnet. Both working parts can move in the vertical direction and change the spacing between the magnets.

[0009] Preferably, the assembly further includes a connecting mechanism, which includes a support frame and a support member. The upper end of the support frame is fixedly connected to the support member, and the lower end is fixedly connected to the limiting member. The negative stiffness component also includes a positioning member, which is fixedly connected to one side of the support member. The positioning member has multiple positioning surfaces arranged vertically along the circumference of the positive stiffness spring, and the driving mechanism is located on one side of the positioning surface.

[0010] Preferably, a first rotating shaft and a second rotating shaft are fixedly connected to the base platform. Both the first rotating shaft and the second rotating shaft are arranged in a vertical direction. A rotating hole is opened at the lower end of the screw. The first rotating shaft extends into the rotating hole. A driven gear is sleeved on the outside of the screw. The driven gear is fixedly connected to the screw. A driving gear is sleeved on the outside of the second rotating shaft. The driving gear can rotate around the second rotating shaft. The driving gear meshes with the driven gear. Rotating the driving gear can drive the screw to rotate relative to the first rotating shaft and change the degree of screwing of the screw into the positive stiffness spring.

[0011] Preferably, the driving mechanism includes a driving member, a first rack, a second rack, and a central gear. The central gear is rotatably connected to a positioning surface. The first rack and the second rack are respectively disposed on both sides of the central gear and both mesh with the central gear. The driving end of the driving member is fixedly connected to the first rack. Both the first rack and the second rack are provided with working parts. The driving end of the driving member can drive the first rack to move on a vertical axis. The first rack can drive the central gear to rotate and drive the second rack to move on a vertical axis.

[0012] Preferably, a permanent magnet damping cylinder is also sleeved on the outside of the negative stiffness component. The permanent magnet damping cylinder is made of conductive material, and its position corresponds to the position of the negative stiffness component. One end of the permanent magnet damping cylinder is fixedly connected to one side of the support member.

[0013] Preferably, multiple assemblies of the positive stiffness component and the negative stiffness component are arranged sequentially along the circumference of the load platform. A flexible hinge is provided between each pair of adjacent assemblies. The two ends of the flexible hinge are respectively fixedly connected to the two adjacent assemblies. The thickness of a portion of the flexible hinge in the vertical direction is less than the thickness of other portions in the vertical direction.

[0014] Preferably, the damping device includes an inner mounting component, an outer mounting component, and the wire. One end of the inner mounting component is a fifth working end, which is fixedly connected to the load platform. The wire is wound around the outside of the inner mounting component. The outer mounting component is made of conductive material, and one end of the outer mounting component is a sixth working end, which is fixedly connected to the base platform. The outer mounting component has a receiving cavity extending vertically from its top surface. The portion of the inner mounting component with the wire wound around it extends into the receiving cavity. There is a gap between the wire wound on the inner mounting component and the inner surface of the outer mounting component. There is a gap between the lower end of the inner mounting component and the base platform. The current on the wire is adjustable.

[0015] Preferably, it also includes a controller, which is signal-connected to the drive mechanism and the wire, and the controller is capable of controlling the stiffness of the negative stiffness component and the magnitude of the current in the wire.

[0016] The present invention achieves the following technical effects compared to the prior art:

[0017] The vibration isolator with adjustable stiffness and damping provided by this invention includes a positive stiffness component, a negative stiffness component, and a damping device between the load platform and the foundation platform. All three components are adjustable. Adjusting the positive stiffness component allows for adjustment of the positive stiffness between the load platform and the foundation platform, enabling the load platform to withstand different static loads. Adjusting the negative stiffness component allows for adjustment of the negative stiffness, changing the dynamic stiffness of the system and thus reducing its natural frequency. Electromagnetic damping can be adjusted by changing the current in the conductor to meet the vibration isolation requirements of different equipment. It offers rapid response and high reliability, requires no sealing, can adapt to complex operating environments, and has a wide range of applications. The damping device, positive stiffness component, and negative stiffness component work together to effectively maintain low dynamic stiffness under high load, improving the vibration isolation performance of the system and reducing the amplitude of the system's transmitted resonance peak. Therefore, the vibration isolator with adjustable stiffness and damping provided by the present invention realizes the adjustment of stiffness between the load platform and the foundation platform through adjustable positive stiffness components and negative stiffness components; and realizes the adjustment of damping by changing the magnitude of the current in the conductor of the damping device. It does not require sealing, can adapt to complex operating environments, and has a wide range of applications. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A three-dimensional structural diagram of the vibration isolator with adjustable stiffness and damping provided by the present invention;

[0020] Figure 2 for Figure 1 A three-dimensional structural diagram of the basic platform;

[0021] Figure 3 for Figure 1 3D structural diagram of a medium-load platform;

[0022] Figure 4 for Figure 1 A three-dimensional structural diagram of the combination of neutral stiffness component and negative stiffness component;

[0023] Figure 5 A three-dimensional structural diagram of a rigidity component after installing a flexible hinge.

[0024] Figure 6 A three-dimensional structural diagram of a positive stiffness spring after the installation of a limiting component;

[0025] Figure 7 A three-dimensional structural diagram of the negative stiffness component mounted on the connecting mechanism;

[0026] Figure 8 This is a side view of a negative stiffness component.

[0027] Figure 9 A top view of the assembly of positive stiffness components and negative stiffness components fitted with a permanent magnet damping cylinder;

[0028] Figure 10 for Figure 5 3D structural diagram of a flexible hinge;

[0029] Figure 11 This is a schematic diagram illustrating the principle of a traditional passive vibration isolation mechanism.

[0030] Figure 12 A schematic diagram illustrating the principle of the vibration isolator with adjustable stiffness and damping provided by the present invention;

[0031] Figure 13 A front view of the tilted state of the load platform of the vibration isolator with adjustable stiffness and damping provided by the present invention;

[0032] Figure 14 A front view of the load platform of the vibration isolator with adjustable stiffness and damping provided by the present invention after leveling.

[0033] Figure 15 A comparison of the transmissivity curves of the vibration isolator with adjustable stiffness and damping provided by the present invention and the traditional passive vibration isolation mechanism.

[0034] In the diagram: 1-Load platform, 2-Foundation platform, 21-First rotating shaft, 22-Second rotating shaft, 23-Limiting part, 3-Damping device, 31-Inner mounting part, 32-Outer mounting part, 33-Wire, 4-Positive stiffness component, 41-Positive stiffness spring, 42-Screw, 43-Limiting part, 44-Driving gear, 45-Driven gear, 5-Negative stiffness component, 51-Magnet mechanism, 511-Upper magnet, 512-Main magnet, 513-Lower magnet, 52-Drive mechanism, 521-Driver, 522-First rack, 523-Second rack, 524-Center gear, 525-Working part, 53-Positioning part, 6-Connecting mechanism, 61-Support frame, 62-Supporting part, 7-Flexible hinge, 8-Permanent magnet damping cylinder, 9-Controller. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides a vibration isolator with adjustable stiffness and damping, such as... Figure 1-10 As shown, it includes a load platform 1, a base platform 2, a damping device 3, a positive stiffness component 4, and a negative stiffness component 5. The base platform 2 is located below the load platform 1. The positive stiffness component 3, the negative stiffness component 4, and the damping device 3 are all located between the base platform 2 and the load platform 1. The two working ends of each of the damping device 3, the positive stiffness component 4, and the negative stiffness component 5 are respectively connected to the load platform 1 and the base platform 2. The stiffness of the positive stiffness component 4 and the negative stiffness component 5 is adjustable. The damping device 3 can change its damping by changing the magnitude of the current on the conductor 33 on the damping device 3.

[0037] The vibration isolator with adjustable stiffness and damping provided by this invention includes a positive stiffness component 4, a negative stiffness component 5, and a damping device 3 between a load platform 1 and a foundation platform 2. All three components are adjustable. Adjusting the positive stiffness component 4 allows for adjustment of the positive stiffness between the load platform 1 and the foundation platform 2, enabling the load platform 1 to withstand different static loads. Adjusting the negative stiffness component 5 allows for adjustment of the negative stiffness, changing the dynamic stiffness of the system and thus reducing its natural frequency. The electromagnetic damping can be adjusted by changing the current in the conductor 33 to meet the vibration isolation requirements of different equipment. This method is fast-responding and highly reliable, requires no sealing, can adapt to complex operating environments, and has a wide range of applications. The damping device 3, positive stiffness component 4, and negative stiffness component 5 work together to effectively maintain low dynamic stiffness under high load, improving the vibration isolation performance of the system and reducing the amplitude of the system's transmitted resonance peak. Therefore, the vibration isolator with adjustable stiffness and damping provided by the present invention realizes the adjustment of stiffness between load platform 1 and foundation platform 2 through adjustable positive stiffness component 4 and negative stiffness component 5; and realizes the adjustment of damping by changing the magnitude of current in conductor 33 on damping device 3. It does not require sealing, can adapt to complex use environment, and has a wide range of applications.

[0038] In a preferred embodiment of this first embodiment, the positive stiffness component 4 includes a vertically arranged positive stiffness spring 41 and a screw 42. At least a portion of the screw 42 extends into the positive stiffness spring 41 and is threadedly connected to the positive stiffness spring 41. The end of the positive stiffness spring 41 away from the screw 42 is the first working end, which is fixedly connected to the load platform 1. The end of the screw 42 away from the positive stiffness spring 41 is the second working end, which is rotatably connected to the base platform 2. A limiting member 43 is fixedly connected to the positive stiffness spring 41, and a limiting part 23 is fixedly connected to the base platform 2. The limiting part 23 can limit the horizontal position of the limiting member 43. The screw 42 is fixed in position in the vertical direction and can rotate relative to the connection between the screw 42 and the base platform 2, thereby changing the degree of screw insertion of the screw 42 into the positive stiffness spring 41. The positive stiffness spring 41 can move up or down as the degree of screw insertion of the screw 42 into the positive stiffness spring 41 changes, thereby causing the load platform 1 to move up or down. By changing the degree to which the screw 42 is screwed into the stiffness spring 41, the length of the threaded connection between the stiffness spring 41 and the screw 42 can be changed, thereby changing the length of the effective elastic part of the stiffness spring 41, making the adjustment of the stiffness more convenient. When the load on the load platform 1 is uneven, it is easy to cause the platform to tilt, affecting the normal vibration isolation. While adjusting the stiffness, the stiffness spring 41 can move up or down as the screw 42 is screwed in, thus adjusting the distance between the load platform 1 and the foundation platform 2 at the same time as adjusting the stiffness, so that the load platform 1 and the equipment are always kept in a horizontal state, enhancing the vibration isolation effect.

[0039] Specifically, the positive stiffness spring 41 is a cylinder with a threaded hole on one end face. Multiple identical positive stiffness grooves are formed along the circumference of the positive stiffness spring 41 on its side surface. These grooves are machined using wire cutting. Each groove has a semi-circular cross-section in the horizontal direction. The grooves are arranged sequentially from the upper to the lower end of the positive stiffness spring 41, with an angle of 90° between adjacent grooves. Compared to traditional helical springs, this positive stiffness spring 41, due to the use of wire cutting to create multiple grooves, has greater stiffness and stronger load-bearing capacity. The limiting member 43 includes an inner ring and an outer ring. The inner ring is sleeved and fixedly connected to the outside of the positive stiffness spring. The inner and outer rings are fixedly connected by a limiting rod. The limiting part 23 consists of two vertically arranged rods, with the limiting rod positioned between them to restrict the horizontal rotation of the positive stiffness spring 41.

[0040] The relationship between the positive stiffness and the effective spring height H satisfies:

[0041]

[0042] H = H0 - ΔH

[0043] In the formula, K is the positive stiffness, k0 is the stiffness proportionality coefficient, H is the effective spring height, H0 is the original length of the variable stiffness spring, and ΔH is the height of the variable stiffness spring when the screw 42 is screwed into it.

[0044] In a preferred embodiment of this first embodiment, the negative stiffness component 5 includes a magnet mechanism 51 and a drive mechanism 52. The magnet mechanism 51 includes an upper magnet 511, a main magnet 512, and a lower magnet 513 with opposite magnetic poles facing each other. The upper magnet 511 and the lower magnet 513 form a third working end, and the main magnet 512 forms a fourth working end. The fourth working end is fixedly connected to the load platform 1. The drive mechanism 52 is fixedly connected to the positive stiffness spring 41. The drive mechanism 52 has two working parts 525 that can move in the vertical direction. The upper magnet 511 and the lower magnet 513 are arranged sequentially from top to bottom and are fixedly connected to one working part 525 respectively. That is, the third working end is connected to the base platform 2 through the drive mechanism 52 and the positive stiffness component 4. The main magnet 512 is arranged between the upper magnet 511 and the lower magnet 513. Both working parts 525 can move in the vertical direction and change the distance between each magnet. The working part 525 moves vertically and changes the distance between the upper magnet 511 and the main magnet 512, and the distance between the lower magnet 513 and the main magnet 512. At the same time, it changes the magnitude of the attraction between opposite magnetic poles, thereby achieving the adjustment of negative stiffness. This adjustment method utilizes magnetic force, and there is no need for the magnets to contact each other. Compared with traditional negative stiffness springs, it reduces friction and makes the adjustment more precise.

[0045] Specifically, each main magnet 512 has a connecting rod fixedly connected to both sides, and the end of the connecting rod away from the main magnet 512 is fixedly connected to the lower side of the load platform 1.

[0046] Among them, the upper magnet 511, the main magnet 512, and the lower magnet 513 are all cuboids. The upper magnet 511 and the lower magnet 513 have the same shape and size. The relationship between the negative stiffness and the magnet spacing h satisfies:

[0047]

[0048]

[0049]

[0050] U ij =x + (-1) j a'-(-1) i a

[0051] V kl =y + (-1) l b'-(-1) k b

[0052] W pq = z + (-1) q c'-(-1) p c

[0053]

[0054] In the formula, k is the negative stiffness of the permanent magnet, z is the displacement of the main magnet 512 in the direction, h is the distance between the main magnet 512 and the upper magnet 511 and the lower magnet 513 when the main magnet 512 is in the equilibrium position; K(z) is the expression for calculating the magnitude of the negative stiffness between adjacent magnets, where J and J' are the magnetic polarization intensity vectors of the two magnets, and μ0 is the permeability of free space. (x,y,z) are the geometric center coordinates of the main magnet 512, (a,b,c) are half the length, width and height of the main magnet 511, and (a',b',c') are half the length, width and height of the upper magnet 511 and the lower magnet 513, respectively.

[0055] In a preferred embodiment of this first embodiment, the vibration isolator with adjustable stiffness and damping provided by the present invention further includes a connecting mechanism 6. The connecting mechanism 6 includes a support frame 61 and a support member 62. The upper end of the support frame 61 is fixedly connected to the support member 62, and the lower end is fixedly connected to the limiting member 43. The negative stiffness component 5 also includes a positioning member 53, which is fixedly connected to one side of the support member 62. The positioning member 53 has multiple positioning surfaces arranged vertically around the positive stiffness spring 41. The driving mechanism 52 is arranged on one side of the positioning surface. The negative stiffness component 5 is connected to the positive stiffness spring 41 through the connecting mechanism 6, so that it can move together with the positive stiffness spring 41 in the vertical direction, thereby realizing the adjustment of the distance between the load platform 1 and the base platform 2. Compared with setting and adjusting the positive stiffness component 4 and the negative stiffness component 5 separately, the setting method in this embodiment makes the adjustment of the distance between the load platform 1 and the base platform 2 simpler. The positioning component 53 is a rectangular cylindrical body with four positioning surfaces. The upper magnet 511, lower magnet 513 and main magnet 512 on different positioning surfaces are arranged in parallel. The rectangular cylindrical arrangement of the positioning component 53 can make the position distribution of each negative stiffness component 5 more uniform, and the magnetic lines of force are constrained by the magnetic yoke, thereby reducing magnetic leakage and increasing the magnetic negative stiffness provided by the negative stiffness component 5.

[0056] Specifically, the positioning element 53 is sleeved on the outside of the positive stiffness spring 41; the support element 62 is a disc with a central opening, sleeved on the outside of the positive stiffness spring 41; the support frame 61 consists of four or more vertically arranged rods. The lower end of the support frame 61 is fixedly connected to the upper side of the limiting element 43, the upper end of the support frame 61 is fixedly connected to the lower side of the support element 62, and one end of the positioning element 53 is fixedly connected to the upper side of the support element 62.

[0057] In a preferred embodiment of this first example, a first rotating shaft 21 and a second rotating shaft 22 are fixedly connected to the base platform 2. Both the first rotating shaft 21 and the second rotating shaft 22 are arranged vertically. A rotating hole is provided at the lower end of the screw 42, and the first rotating shaft 21 extends into the rotating hole. A driven gear 45 is sleeved on the outside of the screw 42, and the driven gear 45 is fixedly connected to the screw 42. A driving gear 44 is sleeved on the outside of the second rotating shaft 22, and the driving gear 44 can rotate around the second rotating shaft 22. Preferably, a handle is provided on the driving gear 44. The driving gear 44 meshes with the driven gear 45. Rotating the driving gear can drive the screw 42 to rotate relative to the first rotating shaft 21 and change the degree of screw engagement of the screw 42 in the positive stiffness spring 41. By rotating the driving gear 44, the driven gear 45 can be driven to rotate, thereby changing the degree of screw engagement of the screw 42 in the positive stiffness spring 41. The entire adjustment process is completed through mechanical transmission, which greatly improves the accuracy and stability of the positive stiffness adjustment. In order to make the load-bearing capacity of the load platform 1 and the base platform 2 more even, the base platform 2 is rectangular, and multiple first rotating shafts 21 and second rotating shafts 22 are provided, which are respectively located near the four corners of the base platform 2.

[0058] In a preferred embodiment of this first embodiment, the drive mechanism 52 includes a drive member 521, a first rack 522, a second rack 523, and a central gear 524. The central gear 524 is rotatably connected to a positioning surface. The first rack 522 and the second rack 523 are respectively disposed on both sides of the central gear 524 and both mesh with the central gear 524. The drive end of the drive member 521 is fixedly connected to the first rack 522. Both the first rack 522 and the second rack 523 are provided with working parts 525. The drive end of the drive member 521 can drive the first rack 522 to move on the vertical axis. The first rack 522 can drive the central gear 524 to rotate and drive the second rack 523 to move on the vertical axis. By driving the first rack 522 to move on the vertical axis through the driving end of the driving component 521, and driving the second rack 523 to move in the opposite direction on the vertical axis, the distance between the upper magnet 511 and the main magnet 512, as well as the distance between the lower magnet 513 and the main magnet 512, can be adjusted. By using the meshing of the central gear 524, the first rack 522 and the second rack 523, more precise position adjustment can be achieved, and the accuracy of negative stiffness adjustment can be improved.

[0059] Specifically, the driving component 521 is an electric push rod whose driving end can move in the vertical direction. A push rod connector arranged in the horizontal direction is fixedly connected to the driving end. The end of the push rod connector away from the driving end is fixedly connected to the first rack 522. The first rack 522 and the second rack 523 are respectively sleeved on two parallel vertical shafts and are upper limited in the vertical direction. The central gear 524 is disposed between the two vertical shafts and meshes with the first rack 522 and the second rack 523 respectively. A working part 525 is fixedly connected to the upper end of the first rack 522 and the lower end of the second rack 523 respectively.

[0060] In a preferred embodiment of this first example, a permanent magnet damping cylinder 8 is further sleeved on the outside of the negative stiffness component 5. The permanent magnet damping cylinder 8 is made of conductive material, preferably copper. The position of the permanent magnet damping cylinder 8 corresponds to the position of the negative stiffness component 5, and one end of the permanent magnet damping cylinder 8 is fixedly connected to one side of the support member 62. When the load platform 1 vibrates, the main magnet 512 moves vertically along with the load platform 1. The permanent magnet damping cylinder 8 can generate a permanent magnet damping force opposite to the direction of movement with the main magnet 512 to hinder the vertical movement of the load platform 1, thereby improving the vibration isolation performance. At the same time, the permanent magnet damping cylinder 8, the positive stiffness component 4, and the negative stiffness component 5 together form a parallel structure of positive stiffness, negative stiffness, and permanent magnet damping. The structures are tightly fitted together, further improving the vibration isolation performance.

[0061] In a preferred embodiment of this first example, multiple assemblies of positive stiffness component 4 and negative stiffness component 5 are sequentially arranged along the circumference of the load platform 1. A flexible hinge 7 is provided between each pair of adjacent assemblies, with both ends of the flexible hinge 7 fixedly connected to the two adjacent assemblies. A portion of the flexible hinge 7 has a thickness in the vertical direction that is less than the thickness of other portions in the vertical direction. For example... Figure 10 The flexible hinge 7 shown has a portion with a smaller thickness in the vertical direction than other parts, which reduces its stiffness in the z and Rx directions while maintaining greater stiffness in other directions. This allows for variable stiffness in the vertical direction while limiting the horizontal stiffness between the load platform 1 and the foundation platform 2, thereby further improving the vibration isolation performance of the isolator. Preferably, semi-circular grooves with a vertical cross-section are formed on the two upper and two lower sides near the two ends of the flexible hinge 7, and these grooves are symmetrically arranged with respect to the horizontal plane passing through the axis of the flexible hinge 7.

[0062] Specifically, the flexible hinge 7 is located at the upper end of the positive stiffness component 4. The middle part of the flexible hinge 7 is connected to the load platform 1 by screws. A strip-shaped groove connecting both sides of the load platform 1 is formed directly above the flexible hinge 7, extending from the upper end of the positive stiffness component 4 towards the connection point between the middle of the flexible hinge 7 and the load platform 1. This arrangement secures the middle part of the flexible hinge 7, thereby increasing the horizontal stiffness between the various components and enhancing vibration isolation.

[0063] In a preferred embodiment of this first example, the damping device 3 includes an inner mounting component 31, an outer mounting component 32, and a wire 33. One end of the inner mounting component 31 is a fifth working end, which is fixedly connected to the load platform 1. The wire 33 is wound around the outside of the inner mounting component 31. The outer mounting component 32 is made of conductive material, and one end of the outer mounting component 32 is a sixth working end, which is fixedly connected to the base platform 2. The outer mounting component 32 has a receiving cavity extending vertically from its top surface. The portion of the inner mounting component 31 with the wire 33 wound around it extends into the receiving cavity. A gap is left between the wire 33 wound on the inner mounting component 31 and the inner surface of the outer mounting component 31. A gap is left between the lower end of the inner mounting component 31 and the base platform 2. The current on the wire 33 can be adjusted. By changing the current, the damping is adjusted accordingly, increasing the sensitivity of the damping adjustment. The current is easy to control, has high reliability, and is less prone to noise generation.

[0064] Specifically, the inner mounting component 31 is a cylinder, and the inner mounting component 31 is a copper tube. The wire 33 is wound around the side of the inner mounting component 31 near the lower end and extends into the outer mounting component 32. The cross-sectional diameter of the outer mounting component 32 is larger than the cross-sectional diameter of the part of the inner mounting component 31 where the wire 33 is wound.

[0065] The relationship between the electromagnetic damping force and the current I satisfies:

[0066] F = K d BLv

[0067] B = μnl

[0068] In the formula, F is the damping force, and K d ρ is the proportionality constant, B is the magnetic flux density, L is the conductor length, v is the conductor velocity, μ is the permeability, n is the number of turns per unit length of the coil, and I is the current in the conductor.

[0069] In a preferred embodiment of this first example, a controller 9 is further included. The controller 9 is signal-connected to the negative stiffness component 5 and the wire 33. The controller 9 can control the stiffness of the negative stiffness component 5 and the magnitude of the current in the wire 33. By controlling the setting of the negative stiffness of the negative stiffness component 5 and the magnitude of the current in the wire 33 through the controller 9, the negative stiffness and damping can be adjusted remotely, making the adjustment of negative stiffness and damping more convenient. Specifically, the controller 9 is signal-connected to the drive component and can control the movement of the drive end of the drive component 521.

[0070] The principle of the adjustable stiffness and damping vibration isolator provided by this invention, and its beneficial effects compared to traditional passive vibration isolation mechanisms, are as follows:

[0071] The principle of traditional vibration isolation mechanisms is as follows: Figure 11 As shown:

[0072] Traditional passive vibration isolation mechanisms consist of spring-mass-damping units, and the system's transfer function G(s)' can be written as:

[0073]

[0074] In the formula, x is o For the vibration displacement response of load platform 1, x i The displacement excitation is for the basic platform 2; m1 is the mass of the load platform 1, c is the system damping, k is the system stiffness, and s is a complex variable in the Lagrange domain.

[0075] like Figure 12 As shown, compared with traditional vibration isolation systems with fixed parameters, the vibration isolator with adjustable stiffness and damping provided by this invention introduces a parallel mechanism of positive and negative stiffness, and a parallel mechanism of permanent magnet damping and electromagnetic damping, the magnitude of which is adjustable, increasing the system flexibility. The system transfer function is obtained as follows:

[0076]

[0077] In the formula, x is o Vibration displacement response of the load platform, x i The basic platform displacement excitation is given by m1, the load platform mass is given by k1, the adjustable positive stiffness is given by k2', the adjustable negative stiffness is given by c1, the permanent magnet damping is given by c2', and the system equivalent stiffness is given by k. e =k'1+k2', equivalent damping c e =c1+c2'.

[0078] like Figure 13 As shown, when the mass distribution of the load platform 1 is uneven, the load platform 1 is tilted. At this time, the height from the base platform 2 to the limiting component 43 is h1. By adjusting the screw 42 to h2, the load platform 1 can be adjusted to a horizontal state. Figure 14As shown, this keeps the load platform 1 horizontal.

[0079] Figure 15 A comparison of the transmissivity curves of the adjustable stiffness and damping vibration isolator provided by this invention and a traditional vibration isolation mechanism is shown in the figure. The solid line in the figure represents the transmissivity curve of the traditional vibration isolation mechanism, which has a higher natural frequency and a larger resonance peak at that frequency. When adjusting only the stiffness: The adjustable stiffness and damping vibration isolator provided by this invention uses parallel connection of adjustable positive and negative stiffnesses. While the positive stiffness k1' provides high static load-bearing capacity, adjusting the negative stiffness reduces the equivalent stiffness k of the system. e Due to the system's inherent frequency With k e The reduction in frequency shifts the system's natural frequency forward, increasing the effective vibration isolation bandwidth while simultaneously lowering the resonance peak value. Figure 15 As shown by the dashed line. The effect of adjusting the damping alone is as follows. Figure 15 As shown by the dashed line, increasing the electromagnetic damping c2' can reduce the peak value at the resonant frequency. By simultaneously adjusting the positive and negative stiffness and damping, the natural frequency can be shifted to the left, further reducing the resonant peak value, as shown below. Figure 15 As shown by the double-dotted line, it can be seen that the present invention can improve vibration isolation performance. Furthermore, the vibration isolator provided by the present invention has adjustable stiffness and damping, requiring no sealing, and can be used for vibration isolation under different load masses and operating conditions, thus having a wide range of applications.

[0080] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A vibration isolator with adjustable stiffness and damping, characterized in that: It includes a load platform, a base platform, a damping device, a positive stiffness component, and a negative stiffness component; the base platform is disposed below the load platform, and the positive stiffness component, the negative stiffness component, and the damping device are all disposed between the base platform and the load platform. The damping device, the positive stiffness component, and the negative stiffness component each have two working ends connected to the load platform and the base platform, respectively. The stiffness of the positive stiffness component and the negative stiffness component is adjustable. The damping device can change its damping by changing the magnitude of the current in the wires on the damping device. The positive stiffness component includes a vertically arranged positive stiffness spring and a screw. At least a portion of the screw extends into the positive stiffness spring and is threadedly connected to it. The end of the positive stiffness spring away from the screw is a first working end, which is fixedly connected to the load platform. The end of the screw away from the positive stiffness spring is a second working end, which is rotatably connected to the base platform. A limiting member is fixedly connected to the positive stiffness spring, and a limiting part is fixedly connected to the base platform. The limiting part can limit the horizontal position of the limiting member. The screw is fixed in the vertical direction and can be positioned relative to the load platform. The screw rotates at the connection point with the base platform, thereby changing the degree to which the screw is screwed into the positive stiffness spring. The positive stiffness spring can move up or down as the degree to which the screw is screwed into the positive stiffness spring changes, thus causing the load platform to move up or down. The negative stiffness component includes a magnet mechanism and a drive mechanism. The magnet mechanism includes an upper magnet, a main magnet, and a lower magnet with opposite magnetic poles facing each other. The upper magnet and the lower magnet form a third working end, and the main magnet forms a fourth working end. The fourth working end is fixedly connected to the load platform. The drive mechanism is fixedly connected to the positive stiffness spring. The drive mechanism has two working parts that can move in the vertical direction. The upper magnet and the lower magnet are arranged sequentially from top to bottom and are fixedly connected to one of the working parts, that is, the third working end is connected to the base platform through the drive mechanism and the positive stiffness component. The main magnet is arranged between the upper magnet and the lower magnet. Both working parts can move in the vertical direction and change the distance between the magnets.

2. The vibration isolator with adjustable stiffness and damping according to claim 1, characterized in that: It also includes a connecting mechanism, which includes a support frame and a support member. The upper end of the support frame is fixedly connected to the support member, and the lower end is fixedly connected to the limiting member. The negative stiffness component also includes a positioning member, which is fixedly connected to one side of the support member. The positioning member has multiple positioning surfaces arranged vertically along the circumference of the positive stiffness spring. The driving mechanism is located on one side of the positioning surface.

3. The vibration isolator with adjustable stiffness and damping according to claim 1, characterized in that: A first rotating shaft and a second rotating shaft are fixedly connected to the base platform. Both the first and second rotating shafts are arranged vertically. A rotating hole is opened at the lower end of the screw. The first rotating shaft extends into the rotating hole. A driven gear is sleeved on the outside of the screw. The driven gear is fixedly connected to the screw. A driving gear is sleeved on the outside of the second rotating shaft. The driving gear can rotate around the second rotating shaft. The driving gear meshes with the driven gear. Rotating the driving gear can drive the screw to rotate relative to the first rotating shaft and change the degree of screw engagement of the screw in the positive stiffness spring.

4. The vibration isolator with adjustable stiffness and damping according to claim 2, characterized in that: The driving mechanism includes a driving component, a first rack, a second rack, and a central gear. The central gear is rotatably connected to a positioning surface. The first rack and the second rack are respectively disposed on both sides of the central gear and both mesh with the central gear. The driving end of the driving component is fixedly connected to the first rack. Both the first rack and the second rack are provided with working parts. The driving end of the driving component can drive the first rack to move on a vertical axis. The first rack can drive the central gear to rotate and drive the second rack to move on a vertical axis.

5. The vibration isolator with adjustable stiffness and damping according to claim 2, characterized in that: The negative stiffness component is further fitted with a permanent magnet damping cylinder, which is made of conductive material. The position of the permanent magnet damping cylinder corresponds to the position of the negative stiffness component, and one end of the permanent magnet damping cylinder is fixedly connected to one side of the support member.

6. The vibration isolator with adjustable stiffness and damping according to claim 2, characterized in that: Multiple assemblies of the positive stiffness component and the negative stiffness component are arranged sequentially along the circumference of the load platform. A flexible hinge is provided between each pair of adjacent assemblies. The two ends of the flexible hinge are fixedly connected to the two adjacent assemblies respectively. The thickness of a part of the flexible hinge in the vertical direction is less than the thickness of other parts in the vertical direction.

7. The vibration isolator with adjustable stiffness and damping according to claim 1, characterized in that: The damping device includes an inner mounting component, an outer mounting component, and the wire. One end of the inner mounting component is a fifth working end, which is fixedly connected to the load platform. The wire is wound around the outside of the inner mounting component. The outer mounting component is made of conductive material, and one end of the outer mounting component is a sixth working end, which is fixedly connected to the base platform. The outer mounting component has a receiving cavity extending vertically from its top surface. The portion of the inner mounting component with the wire wound around it extends into the receiving cavity. There is a gap between the wire wound on the inner mounting component and the inner surface of the outer mounting component. There is a gap between the lower end of the inner mounting component and the base platform. The current on the wire is adjustable.

8. The vibration isolator with adjustable stiffness and damping according to claim 1, characterized in that: It also includes a controller, which is connected to the drive mechanism and the wire signal. The controller can control the stiffness of the negative stiffness component and the magnitude of the current in the wire.

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