High-end instrument equipment heavy load precision gas magnetic composite low frequency micro-vibration isolator

Abstract

High-end instrument equipment heavy load precision gas magnetic composite low frequency micro-vibration isolator belongs to the technical field of precision vibration isolation, which is coaxially nested by a moving magnetic ring array and a fixed magnetic ring array, and the moving magnetic ring array and the fixed magnetic ring array are both composed of 2n+1 (n >= 1, n belongs to N + ) layers of equal-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers, and the overall structure is symmetric about the n+1 layer of magnetic rings; the first layer of magnetic rings of the moving magnetic ring array and the fixed magnetic ring array are radially oppositely magnetized, and their bottom surfaces coincide; with each additional layer, the magnetization direction of the moving magnetic ring rotates clockwise by 90 degrees, while the magnetization direction of the fixed magnetic ring rotates counterclockwise by 90 degrees; the present application has a simple structure, is easy to install and maintain, can produce high negative stiffness and zero magnetic force characteristics, and can reduce the dynamic vibration isolation stiffness without changing the heavy load precision micro-vibration bearing of tens of tons to thousands of tons, thereby realizing low-frequency or near-zero-frequency vibration isolation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of precision vibration isolation, and particularly relates to a high-end instrument and equipment heavy-load precision gas-magnetic composite low-frequency micro-vibration isolator. BACKGROUND

[0002] With the rapid iteration and upgrading of large-scale precision machining equipment, measuring instruments and large-scale cutting-edge scientific experiment systems, the machining and measuring precision of high-end precision instruments and equipment has entered the nanometer and sub-nanometer level, and the sensitivity to micro-vibration in the environment has also gradually increased. Even the low-frequency micro-vibration interference that cannot be perceived by human senses can seriously affect the precision of large-scale precision machining equipment, measuring instruments and equipment and large-scale cutting-edge scientific experiment systems. Therefore, it is necessary to weaken or isolate environmental vibration, especially low-frequency micro-vibration, which is crucial to the precision of large-scale precision machining, measuring and cutting-edge scientific experiment fields.

[0003] Stiffness is a core parameter for determining the isolation bandwidth, and directly relates to the effect of the micro-vibration isolation platform on different frequency vibrations. The smaller the stiffness of the micro-vibration isolator, the wider the isolation frequency band and the better the low-frequency micro-vibration isolation effect; however, the low stiffness characteristic will lead to high static deformation, low stability and weak anti-interference ability, and reduce the carrying capacity of the micro-vibration isolation platform. Therefore, how to reduce the isolation stiffness without affecting the carrying capacity is the key to improving the isolation performance. The parallel negative stiffness structure can reduce the isolation stiffness and expand the isolation frequency band without affecting the carrying capacity. However, the existing negative stiffness structure research mainly faces small optical micro-vibration isolation platforms and devices, and the mass of these platforms and devices is usually within thousands of kilograms to hundreds of kilograms; when facing the heavy-load micro-vibration isolation demand of large-scale precision machining equipment, measuring instruments and large-scale cutting-edge scientific experiment systems, which are up to tens of tons to thousands of tons, the generated negative stiffness is low, and the effect of reducing the isolation stiffness and expanding the isolation bandwidth is very small. Therefore, for large-scale precision micro-vibration systems with large carrying capacity, large size and complex structure, how to reduce the isolation stiffness and expand the isolation frequency band is the key to realizing high-performance isolation.

[0004] Patent No. CN202010897879.X discloses a bistable nonlinear energy hydra based on electromagnetic negative stiffness, the upper and lower magnetic rings and the upper and lower coils exert attractive force on the middle magnetic ring to form an online adjustable electromagnetic negative stiffness spring, and the electromagnetic negative stiffness spring is connected in parallel with the compression spring to form a bistable nonlinear energy hydra. When the coil is not powered, the performance of the permanent magnetic negative stiffness is adjusted by adjusting the distance between the upper and lower magnetic rings and the middle magnetic ring; when the coil is powered, the electromagnetic negative stiffness performance is adjusted in real time by adjusting the current in the upper and lower coils and the distance between the upper and lower coils and the middle magnetic ring. Patent No. CN202211512185.5 discloses a low-frequency vibration isolation device based on linear magnetic negative stiffness, which realizes linear magnetic negative stiffness by arranging three magnetic rings with equal gaps along the axial direction and configuring coaxial ring coils outside each permanent magnet. Among them, the three ring coils are vertically coaxially symmetrically arranged to form an attractive electromagnetic negative stiffness mechanism, and the three magnetic rings and the three ring coils are vertically coaxially symmetrically arranged to form a repulsive electromagnetic negative stiffness mechanism. The attractive electromagnetic negative stiffness mechanism and the repulsive electromagnetic negative stiffness mechanism are coupled to realize the nonlinear cancellation of the softening stiffness characteristic and the hardening stiffness characteristic. Patent No. CN202311009285.0 discloses a magnetic gas type vibration isolation device and method with adjustable stiffness, which realizes the coarse and fine adjustment of negative stiffness characteristics by arranging four cubic moving permanent magnets inside the vibration isolator and a pair of cubic permanent magnets and a pair of electromagnets fixed in a cross shape. Among them, the adjustable gap between the moving permanent magnets and the fixed permanent magnets realizes the coarse adjustment of negative stiffness, and the size of the current in the electromagnet realizes the fine adjustment of negative stiffness. The above technical solutions all adopt cubic permanent magnets or ring-shaped permanent magnet gap array arrangement, which has a significant magnetic leakage problem, and the negative stiffness value provided is relatively low.

[0005] Professor Cui Junning of Harbin Institute of Technology proposed a kind of ultra-low frequency air spring vibration isolator (1. "Air spring vibration isolator based on electromagnetic negative stiffness structure", ZL202010605223.6; 2. Ultra-low frequency air spring vibration isolator based on axial magnetization magnetic ring negative stiffness structure, ZL202010606309.0; 3. Large load ultra-low frequency air spring vibration isolator based on negative stiffness magnetic spring, ZL202010605236.3; 4. Ultra-low frequency vibration isolator based on vertical magnetization magnetic ring negative stiffness structure, ZL202010605241.4), which realizes negative stiffness characteristics by using radially opposite magnetization, axially same direction magnetization and mutually perpendicular magnetization of inner and outer magnetic rings, and forms an efficient damping mechanism by using the eddy current generated by the relative motion of the inner and outer magnetic rings and the built-in orifice, thereby effectively attenuating vibration energy and improving the stability and vibration isolation performance of the vibration isolation system. Patent No. CN202311375790.7 discloses a high linearity magnetic negative stiffness mechanism with stator misplacement configuration, which is obtained by coaxially nesting the stator magnetic ring and the mover magnetic ring with the same excitation direction and repulsive magnetic force, and arranging them into multiple layers along the z direction or multiple columns along the horizontal direction, so as to increase the negative stiffness value provided by the acting force between the stator magnetic ring and the mover magnetic ring in the z direction, and improve the linearity of the negative stiffness characteristic by setting an initial bias between the mover magnetic ring and the stator magnetic ring of the same layer. Compared with the negative stiffness structure scheme based on the gap array arrangement of cubic permanent magnets, the scheme of coaxially nesting the inner and outer magnetic rings with radial opposite magnetization, axial same direction magnetization and mutually perpendicular magnetization and arranging them into an equal gap array in a certain direction can improve the negative stiffness value. However, in the above technical scheme, the stator and the mover in the negative stiffness mechanism are single magnetic rings with radial magnetization or axial magnetization. For such uniformly magnetized magnetic rings in a certain direction, the excitation magnetic field formed on the inner and outer sides or the upper and lower sides is symmetrical, but only one side of the magnetic field is utilized and the other side is idle, resulting in that the magnetic field utilization rate of this scheme still needs to be optimized, and the negative stiffness value produced has little effect on reducing the stiffness of a few dozen tons to thousands of tons of large precision micro-vibration isolation platform.

[0006] In summary, it is of great significance to provide a device that can reduce the stiffness of heavy load precision micro-vibration isolation, expand the low frequency vibration isolation band, reduce the interference of environmental micro-vibration on high-end precision instruments and equipment, ensure the optimal working environment of high-end precision instruments and equipment, and further improve the precision of high-end precision instruments and equipment through structural and principle innovation. SUMMARY

[0007] The core objective of the present application is to solve the negative influence of environmental vibration interference on high-end precision instruments and equipment, and a high-load precision air-magnetic composite low-frequency micro-vibration isolator is designed by combining the composite magnetic suspension technology and the precision air floating system. The device uses a multi-layer vertical magnetization equal-section magnetic ring array to enhance the working side magnetic field and weaken the non-working side magnetic field, thereby forming a single-side high magnetic density magnetic field. The vertical magnetization moving magnetic ring array and the fixed magnetic ring array are coaxially nested to achieve high negative stiffness characteristics, and are connected in parallel with a large air floating vibration isolator to reduce the inherent frequency of the vibration isolation and expand the vibration isolation range. This design can provide an "ultra-quiet" environment for ultra-precision instruments such as ultra-precision lithography machines, high-resolution satellite cameras, and ultra-precision machine tools, and significantly improves the precision of high-end instruments.

[0008] The technical solution of the present application is:

[0009] The high-load precision air-magnetic composite low-frequency micro-vibration isolator adopts an air floating mode to stably support the load, and combines the magnetic floating technology to generate high negative stiffness characteristics, effectively reduces the vibration isolation stiffness, and realizes low-frequency or even near-zero frequency vibration isolation. The high-load precision air-magnetic composite low-frequency micro-vibration isolator is characterized by comprising a load platform, a vertical magnetization space negative stiffness array, and a large air floating micro-vibration isolator. The large air floating micro-vibration isolator comprises an upper cover plate, an elastic membrane, a main air tank, an additional air tank, and compressed gas. The upper cover plate is fixedly connected with the load platform, and forms a closed air chamber with the elastic membrane and the main air tank. Compressed gas is introduced into the closed air chamber. The vertical magnetization space negative stiffness array comprises coaxially installed moving magnetic ring mounting pieces, a moving magnetic ring array, a fixed magnetic ring array, and fixed magnetic ring mounting pieces, which are arranged outward along the radius from the axis in sequence. The moving magnetic ring mounting piece is a T-shaped cylindrical structure, the top end of which is fixedly connected with the load platform, and the bottom part is kept a certain gap with the ground. The moving magnetic ring array is tightly fitted and fixedly installed on the outer side of the moving magnetic ring mounting piece, and the bottom part is tightly fixed by a moving magnetic ring positioning piece. The moving magnetic ring array and the fixed magnetic ring array are provided with gaps along the radial direction, and the fixed magnetic ring mounting piece is an annular sleeve with a deep groove on the inner side along the circumference, the bottom part of which is fixed, and the top part is kept a certain gap with the load platform. The fixed magnetic ring array is tightly fitted and fixedly installed in the deep groove on the inner side of the fixed magnetic ring mounting piece, and the top part is tightly fixed by a fixed magnetic ring positioning piece. The moving magnetic ring array and the fixed magnetic ring array are each composed of 2n+1 layers of equal-section magnetic rings arranged in an array along the axial direction and vertically magnetized between adjacent layers, wherein n≥1, n∈N + The heights of the magnetic rings in the same layer of the moving magnetic ring array and the fixed magnetic ring array are equal, and the heights of the odd-numbered layers of magnetic rings are equal, and the heights of the even-numbered layers of magnetic rings are equal. The first layer of magnetic rings of the moving magnetic ring array and the fixed magnetic ring array are reversely magnetized along the radial direction, and their bottom surfaces coincide. In the right half of the front view, the magnetization direction of the moving magnetic ring rotates clockwise by 90°, and the magnetization direction of the fixed magnetic ring rotates counterclockwise by 90° with each additional layer.

[0010] Preferably, the vertical magnetization space negative stiffness array is arranged in the adjacent gap of the large air-floating vibration isolation device or is coaxially embedded and fixedly installed in the main air tank of the large air-floating vibration isolation device.

[0011] Preferably, the large air-floating vibration isolation device adopts a steel ring seal, an O-shaped seal, a diaphragm seal or a pressure self-sealing mode.

[0012] Preferably, the pressure of the compressed gas is 0.1 MPa to 0.8 MPa.

[0013] Preferably, the main air tank and the plurality of sealed additional air tanks are connected in series through throttle holes or air pipes.

[0014] Preferably, the moving magnetic ring array and the fixed magnetic ring array are composed of a plurality of radially uniform magnet tiles, and the number of the tiles can be 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tiles is not more than 3°.

[0015] Preferably, the moving magnetic ring mounting member, the fixed magnetic ring fixing member, the moving magnetic ring positioning member and the fixed magnetic ring positioning member are made of non-magnetic or weakly magnetic aluminum alloy or titanium alloy metal materials.

[0016] Preferably, the number of throttle holes between adjacent additional air tanks is different, and the positions of the throttle holes do not coincide.

[0017] Preferably, the throttle hole is triangular, circular, pentagonal or other polygonal.

[0018] The technical innovation of the present application and the good effects produced are as follows:

[0019] (1) The present application innovatively proposes a heavy-load precision gas-magnetic composite low-frequency vibration isolation device for high-end instruments and equipment. The heavy-load precision gas-magnetic composite low-frequency vibration isolation device adopts a large air-floating vibration isolation device and a vertical magnetization space negative stiffness array to support the load platform in parallel, wherein the large air-floating vibration isolation device stably supports a load platform of tens of tons to thousands of tons in an air-floating manner and effectively isolates the vibration in the medium and high frequency bands; and the vertical magnetization space negative stiffness array generates high negative stiffness characteristics by using magnetic floating, generates local low dynamic stiffness characteristics without affecting the bearing capacity of the large air-floating vibration isolation device, reduces the natural frequency of vibration isolation and expands the vibration isolation bandwidth, thereby providing an "ultra-quiet" working environment for high-end instruments and equipment such as ultra-precision lithography machines, high-resolution satellite cameras and ultra-precision machine tools. This is one of the innovative points of the present application which is different from the prior art.

[0020] (2) The present application innovatively proposes a vertical magnetization space negative stiffness array with zero magnetic force and high negative stiffness characteristics. The vertical magnetization space negative stiffness array uses 2n+1 (n≥1, n∈N +) layer along the axial array, the vertical magnetization between adjacent layers of cross-section magnetic ring array array of moving magnetic ring array and fixed magnetic ring array coaxial nesting to build a single side high magnetic density magnetic field, effectively weaken the magnetic field strength of non-working side, while significantly enhancing the magnetic field strength of the working side, so as to produce a high amplitude negative stiffness characteristics sufficient to reduce the tens of tons to thousands of tons of large precision micro-vibration stiffness parameters, reduce the natural frequency of vibration isolation; In addition, the overall structure of the vertical magnetization space negative stiffness array is symmetrical about the upper and lower of the n+1 layer magnetic ring, and the axial magnetic force is zero, which can provide a configuration basis for reducing the vibration isolation stiffness without affecting the heavy load precision micro-vibration bearing. This is the second innovation point of the present application which is different from the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a three-dimensional view of the vertical magnetization space negative stiffness array;

[0022] Figure 2 is a front cross-sectional view of the vertical magnetization space negative stiffness array;

[0023] Figure 3 is a three-dimensional view of the high-end instrument equipment heavy load precision gas magnetic composite low-frequency micro-vibration isolator embodiment 1;

[0024] Figure 4 is a front cross-sectional view of the high-end instrument equipment heavy load precision gas magnetic composite low-frequency micro-vibration isolator embodiment 1;

[0025] Figure 5 is a three-dimensional view of the high-end instrument equipment heavy load precision gas magnetic composite low-frequency micro-vibration isolator embodiment 2;

[0026] Figure 6 is a front cross-sectional view of the high-end instrument equipment heavy load precision gas magnetic composite low-frequency micro-vibration isolator embodiment 2;

[0027] Figures 7-13 Corresponding to 4, 5, 6, 8, 10, 12 or 15 tile-shaped magnet splicing to form a radial magnetization magnetic ring, the relative position and magnetization direction of the moving magnetic ring array and the fixed magnetic ring array are shown in the figure.

[0028] Figure 14 is a front cross-sectional view of the large air floatation micro-vibration isolator when the main air tank and the plurality of additional air tanks are connected in series through the air pipe;

[0029] Figure 15 is a front cross-sectional view of the large air floatation micro-vibration isolator when the main air tank and the plurality of additional air tanks are connected in series through the throttle hole.

[0030] Figure part number explanation: 1 ground, 2 moving magnetic ring array, 3 moving magnetic ring mounting, 4 fixed magnetic ring array, 5 fixed magnetic ring fixing, 6 load platform, 7 vertically magnetized space negative stiffness array, 8 large air floating micro-vibration isolator, 9 upper cover plate, 10 elastic film, 11 main air tank, 12 additional air tank, 13 compressed gas, 14 throttle hole, 15 air pipe, 16 moving magnetic ring positioning piece, 17 fixed magnetic ring positioning piece. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0032] The high-end instrument equipment heavy load precision gas-magnetic composite low-frequency micro-vibration isolator adopts air floating mode to stably support the load, and combines with magnetic floating technology to generate high negative stiffness characteristics, effectively reduces the vibration isolation stiffness, and realizes low-frequency or even near-zero frequency vibration isolation; characterized in that: it comprises a load platform 6, a vertically magnetized space negative stiffness array 7 and a large air floating micro-vibration isolator 8; the large air floating micro-vibration isolator 8 comprises an upper cover plate 9, an elastic film 10, a main air tank 11, an additional air tank 12 and compressed gas 13, the upper cover plate 9 is fixedly connected with the load platform 6, and forms a closed air chamber with the elastic film 10 and the main air tank 11, and the closed air chamber is filled with compressed gas 13; the vertically magnetized space negative stiffness array 7 comprises moving magnetic ring mounting 3, moving magnetic ring array 2, fixed magnetic ring array 4 and fixed magnetic ring fixing 5 which are coaxially installed and arranged outward along the radius from the axis, the moving magnetic ring mounting 3 is a cylindrical structure with a T-shaped cross section, the top end thereof is fixedly connected with the load platform 6, and the bottom part thereof maintains a certain gap with the ground 1; the moving magnetic ring array 2 is tightly fitted and fixedly installed on the outer side surface of the moving magnetic ring mounting 3, and the bottom part thereof is tightly fixed by the moving magnetic ring positioning piece 16; the moving magnetic ring array 2 and the fixed magnetic ring array 4, the fixed magnetic ring fixing 5 are provided with gaps in the radial direction, the fixed magnetic ring fixing 5 is an annular sleeve with a deep groove arranged on the inner side surface along the circumference, the bottom part thereof is fixed, and the top part thereof maintains a certain gap with the load platform 6; the fixed magnetic ring array 4 is tightly fitted and fixedly installed in the deep groove on the inner side surface of the fixed magnetic ring fixing 5, and the top part thereof is tightly fixed by the fixed magnetic ring positioning piece 17; the moving magnetic ring array 2 and the fixed magnetic ring array 4 are both composed of 2n+1 layers of magnetic rings which are arranged in an axial array and vertically magnetized between adjacent layers, wherein n≥1, n∈N + ; the heights of the magnetic rings in the same layer of the moving magnetic ring array 2 and the fixed magnetic ring array 4 are equal, the heights of the magnetic rings in the odd layers are equal, and the heights of the magnetic rings in the even layers are equal; in the right half of the front view, the first layer of magnetic rings of the moving magnetic ring array 2 and the fixed magnetic ring array 4 are reversely magnetized in the radial direction, and the bottom surfaces thereof coincide; with each additional layer, the magnetization direction of the moving magnetic ring rotates clockwise by 90°, and the magnetization direction of the fixed magnetic ring rotates counterclockwise by 90°.

[0033] As a specific embodiment, the vertical magnetization space negative stiffness array 7 is arranged in a gap adjacent to the large air-floating micro-vibration isolator 8 or is coaxially nested and fixedly installed in the main air tank 11 of the large air-floating micro-vibration isolator 8.

[0034] As a specific embodiment, the large air-floating micro-vibration isolator 8 adopts a steel ring seal, an O-ring seal, a diaphragm seal or a pressure self-sealing mode.

[0035] As a specific embodiment, the pressure of the compressed gas 13 is 0.1 MPa to 0.8 MPa.

[0036] As a specific embodiment, the main air tank 11 and the plurality of sealed additional air tanks 12 are connected in series through the throttle holes 14 or the air pipes 15.

[0037] As a specific embodiment, the magnet rings along the radial magnetization in the moving magnet ring array 2 and the fixed magnet ring array 4 are spliced by a plurality of radially uniform magnetized tile-shaped magnets, the number of the tile-shaped magnets can be 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets is not more than 3°.

[0038] As a specific embodiment, the moving magnet ring mounting member 3, the fixed magnet ring fixing member 5, the moving magnet ring positioning member 16 and the fixed magnet ring positioning member 17 are non-magnetic or weakly magnetic aluminum alloy or titanium alloy metal materials.

[0039] As a specific embodiment, the number of the throttle holes 14 between adjacent additional air tanks 12 is different, and the positions of the throttle holes 14 do not coincide.

[0040] As a specific embodiment, the throttle hole 14 is triangular, circular, pentagonal or other polygonal shape.

[0041] The following will be described in combination with Figures 1-4 An embodiment of the present application is given.

[0042] The high-end instrument equipment heavy load precision gas-magnetic composite low-frequency micro-vibration isolator adopts magnetic levitation technology and precise air floating system in parallel composite mode to realize large bearing capacity and low-frequency vibration isolation effect. It is composed of a load platform 6, a vertically magnetized spatial negative stiffness array 7 and a large air floating micro-vibration isolator 8. The vertically magnetized spatial negative stiffness array 7 and the large air floating micro-vibration isolator 8 are arranged in adjacent gaps and support the load platform 6 in parallel. In the vibration isolator, the large air floating micro-vibration isolator 8 stably supports the load platform 6 in an air floating manner and effectively isolates the vibration in the medium and high frequency bands. The vertically magnetized spatial negative stiffness array 7 uses magnetic levitation to generate high negative stiffness characteristics and is connected in parallel with the large air floating micro-vibration isolator 8, further reducing the dynamic vibration isolation stiffness without changing the large bearing capacity, and effectively isolating the low-frequency or near-zero-frequency vibration interference. This vibration isolation technology not only meets the heavy load demand of tens of tons to thousands of tons, but also significantly reduces the dynamic vibration isolation stiffness without sacrificing the bearing capacity, effectively isolating the low-frequency or near-zero-frequency vibration interference, providing an "ultra-quiet" working environment for ultra-precision lithography machines, high-resolution satellite cameras, ultra-precision machine tools and other cutting-edge instruments and equipment, and ensuring the stable operation and high-precision measurement of high-end instruments and equipment.

[0043] The large air floating micro-vibration isolator 8 is the core equipment of the ultra-precision air floating micro-vibration technology, which is a non-metallic spring that fills compressed gas 13 in the elastic membrane 10 and uses the compressibility of the gas to achieve elastic support. In the structural design, the upper cover plate 9 and the load platform 6 are tightly connected through fixed connection, and together with the elastic membrane 10 and the main gas tank 11 form a sealed gas chamber. This gas chamber is sealed by steel ring sealing, O-ring sealing, diaphragm sealing or pressure self-sealing, etc. to ensure the stable existence of the compressed gas 13. In this sealed gas chamber, 0.1 MPa to 0.8 MPa of compressed gas 13 is filled to provide stable elastic support force for the vibration isolator. When there is a small vibration interference from the outside, the compressed gas 13 in the large air floating micro-vibration isolator 8 will be compressed and expanded accordingly according to the frequency and amplitude of the vibration. This dynamic process not only effectively absorbs the vibration energy, but also converts the vibration energy into heat energy through the dissipation of the gas, thereby achieving significant vibration isolation effect. By precisely controlling the pressure of the gas in the gas chamber, the vibration isolator can stably support high-end instruments and equipment of different masses and provide good vibration isolation effect in the medium and high frequency bands.

[0044] The vertical magnetization space negative stiffness array 7 includes the moving magnetic ring array 2, the moving magnetic ring mounting member 3, the fixed magnetic ring array 4 and the fixed magnetic ring fixing member 5. The moving magnetic ring array 2 and the fixed magnetic ring array 4 are coaxially nested and arranged in a radial outward gap along the axis. The moving magnetic ring mounting member 3 is a T-shaped cross-section cylindrical structure, the top end of which is fixedly connected with the load platform 6, and the bottom part of which keeps a gap of 30mm-100mm with the ground 1, which is greater than the sum of the floating height of the large air floating micro-vibration isolator 8 and the maximum vibration amplitude of the load platform 6. The fixed magnetic ring fixing member 5 is an annular sleeve with a deep groove arranged along the circumference on the inner side, the bottom of which is fixed, and the top of which keeps a gap of 30mm-100mm with the load platform 6, which is greater than the sum of the floating height of the large air floating micro-vibration isolator 8 and the maximum vibration amplitude of the load platform 6. The fixed magnetic ring array 4 is tightly fitted and fixedly installed in the deep groove on the inner side of the fixed magnetic ring fixing member 5, and the top part is pressed and fixed by the fixed magnetic ring positioning member 17. The moving magnetic ring mounting member 3 and the fixed magnetic ring fixing member 5 are made of non-magnetic or weakly magnetic aluminum alloy or titanium alloy material, and the magnetic rings are N44H grade ferrous boron permanent magnets, whose residual magnetism is 13.54kGs, intrinsic coercive force is 12.66kOe, and relative permeability μ r =1.23. The bottom surface of the first layer of moving magnetic rings coincides with that of the first layer of fixed magnetic rings, the first layer of moving magnetic rings is magnetized along the axis in a radial direction, and the first layer of fixed magnetic rings is magnetized outward along the axis in a radial direction. In the right half of the front view, the magnetization direction of the moving magnetic ring is rotated clockwise by 90°, and the magnetization direction of the fixed magnetic ring is rotated counterclockwise by 90° with each additional layer of magnetic rings. The radially magnetized magnetic rings in the moving magnetic ring array 2 and the fixed magnetic ring array 4 are all made of 8 pieces of 42° tile-shaped magnets, and the gap between adjacent tile-shaped magnets is 3°.

[0045] Since the number of layers of the moving magnetic ring array 2 and the fixed magnetic ring array 4 satisfies 2n+1 (where n≥1, n∈N +), the whole structure is symmetric about the n+1 th magnetic ring. Therefore, in the static condition, the magnetic forces on the moving magnetic ring array 2 are counteracted, and the system is in a stable equilibrium state. However, when excited by a small axial disturbance, the moving magnetic ring array 2 and the fixed magnetic ring array 4 will move relative to each other, which will break the original axial balance of the moving magnetic ring array 2, while the radial balance is still maintained. During the relative movement, the axial magnetic force exerted by the moving magnetic ring array 2 on the fixed magnetic ring array 4 is consistent with the vibration direction, pushing it further away from the equilibrium position. Once the external force is removed, the system cannot restore itself to the initial equilibrium state. This characteristic makes the vertical magnetization space negative stiffness array 7 exhibit negative stiffness characteristics in the axial direction. When this negative stiffness array is connected in parallel with the large air-floating vibration isolator 8 to support the load platform 6, it can expand the vibration isolation bandwidth by generating negative stiffness characteristics without affecting the tens of tons to thousands of tons of load, effectively isolating low-frequency or even near-zero-frequency vibration interference, thereby improving the overall vibration isolation performance. In addition, when the heights of the magnetic rings in the same layer of the moving magnetic ring array 2 and the fixed magnetic ring array 4 are equal, the negative stiffness value of the vertical magnetization space negative stiffness array 7 reaches the maximum. Compared with the negative stiffness configuration composed of radially opposite magnetization coaxial nested magnetic rings, the negative stiffness value of this configuration can be significantly improved by up to 155 times. Compared with the structure of coaxial nested axial same-direction magnetization magnetic rings, the negative stiffness value can be increased by 21.4 times under the same size.

[0046] Figure 5 With Figure 6 respectively, the three-dimensional view and the front cross-sectional view of the second embodiment of the high-end instrument equipment heavy load precision gas-magnetic composite low-frequency vibration isolator, wherein the vertical magnetization space negative stiffness array 7 is coaxially nested and fixedly installed in the main gas tank 11, connected in parallel with the large air-floating vibration isolator 8 to support the load platform 6, and the moving magnetic ring array 2 and the fixed magnetic ring array 4 are coaxially nested and fixedly installed on the moving magnetic ring mounting member 3 and the fixed magnetic ring fixing member 5, respectively. The top end of the moving magnetic ring mounting member 3 is fixedly connected with the bottom of the upper cover plate 9, and the bottom is kept 30mm-100mm apart from the upper surface of the lower bottom plate of the main gas tank 11, which is greater than the sum of the floating height of the large air-floating vibration isolator 8 and the maximum vibration amplitude of the load platform 6. The bottom of the fixed magnetic ring fixing member 5 is fixedly installed in the main gas chamber of the large air-floating vibration isolator 8, fixedly connected with the upper surface of the lower bottom plate of the main gas tank 11, and kept 30mm-100mm apart from the bottom of the upper cover plate 9.

[0047] The radial magnetization process of the magnetic ring is complex, and the magnetization effect cannot be guaranteed, so multiple radially uniform tile-shaped magnets are often spliced together. Figures 7-13When the 4, 5, 6, 8, 10, 12 or 15 tile type magnets are spliced to form a radially magnetized magnetic ring, the relative position and magnetization direction of the moving magnetic ring array 2 and the fixed magnetic ring array 4 are shown in the schematic diagram, the gap between adjacent tile type magnets is usually not more than 3°, to ensure the continuity and uniformity of the magnetic field.

[0048] Figure 14 With Figure 15 Two specific embodiments of the large air floating vibration isolator 8. In these two designs, the main air tank 11 of the large air floating vibration isolator 8 is connected in series with m additional air tanks 12 through air pipes 15 or orifices 14. The number of orifices 14 between adjacent additional air tanks 12 is different, and the positions do not coincide. The two structures are suitable for occasions with larger horizontal or vertical installation space. Whether it is an air pipe 15 or an orifice 14, it plays a role in limiting the flow rate of gas, so that the heavy load precision vibration isolation system can respond more stably to external vibration. By adjusting the pipe diameter or length of the air pipe 15, the number, size and shape of the orifice 14, the damping characteristics of the vibration isolation system can be optimized to meet different vibration isolation requirements.

Claims

1. A high-end instrument equipment heavy-duty precision air-magnetic composite low-frequency vibration isolator, which uses air levitation to stably support the load and combines it with magnetic levitation technology to generate high negative stiffness characteristics, effectively reducing vibration isolation stiffness and achieving low-frequency or even near-zero-frequency vibration isolation; its features are: The system includes a load platform (6), a vertical magnetized space negative stiffness array (7), and a large air-floating micro-vibrator (8). The large air-floating micro-vibrator (8) includes an upper cover plate (9), an elastic membrane (10), a main air tank (11), an auxiliary air tank (12), and compressed gas (13). The upper cover plate (9) is fixedly connected to the load platform (6) and forms a sealed air chamber with the elastic membrane (10) and the main air tank (11). Compressed gas (13) is introduced into the sealed air chamber. The vertical magnetized space negative stiffness array (7) includes a moving magnetic ring mounting component (3), a moving magnetic ring array (2), a fixed magnetic ring array (4), and a fixed magnetic ring fixing component (5) arranged coaxially from the axis outward along the radius. The moving magnetic ring mounting component (3) is a cylindrical structure with a T-shaped cross section. Its top end is fixedly connected to the load platform (6), and its bottom end is fixedly connected to the load platform (6). The part maintains a certain gap with the ground (1); the moving magnetic ring array (2) is tightly fitted and fixedly installed on the outer side of the moving magnetic ring mounting part (3), and its bottom is pressed and fixed by the moving magnetic ring positioning part (16); the moving magnetic ring array (2) and the fixed magnetic ring array (4) and the fixed magnetic ring fixing part (5) are provided with a gap along the radial direction. The fixed magnetic ring fixing part (5) is an annular sleeve with a deep groove on the inner side along the circumference. Its bottom is fixed and its top maintains a certain gap with the load platform (6); the fixed magnetic ring array (4) is tightly fitted and fixedly installed in the deep groove on the inner side of the fixed magnetic ring fixing part (5), and its top is pressed and fixed by the fixed magnetic ring positioning part (17); the moving magnetic ring array (2) and the fixed magnetic ring array (4) are both composed of 2n+1 layers of uniform cross-section magnetic rings arranged in an axial array and vertically magnetized between adjacent layers, where n≥1, n∈N + The heights of the magnetic rings in the same layer of the moving magnetic ring array (2) and the fixed magnetic ring array (4) are equal, and the heights of the odd-numbered magnetic rings are all equal, and the heights of the even-numbered magnetic rings are all equal; the first layer of magnetic rings in the moving magnetic ring array (2) and the fixed magnetic ring array (4) are magnetized in opposite directions along the radial direction, and their bottom surfaces coincide; on the right half of the front sectional view, with each additional layer, the magnetization direction of the moving magnetic ring rotates 90° clockwise, and the magnetization direction of the fixed magnetic ring rotates 90° counterclockwise.

2. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1, characterized in that: The vertical magnetization spatial negative stiffness array (7) is arranged with an adjacent gap to the large air-bearing micro-vibrator (8) or the vertical magnetization spatial negative stiffness array (7) is coaxially nested and fixedly installed in the main air tank (11) of the large air-bearing micro-vibrator (8).

3. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1 or 2, characterized in that: The large air-float micro-vibrator (8) adopts steel ring sealing, O-ring sealing, diaphragm sealing or pressure self-sealing.

4. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1, characterized in that: The pressure of the compressed gas (13) is 0.1 MPa to 0.8 MPa.

5. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1, characterized in that: The main gas tank (11) and multiple sealed auxiliary gas tanks (12) are connected in series through a throttle orifice (14) or a gas pipe (15).

6. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1, characterized in that: The radially magnetized magnetic rings in the moving magnetic ring array (2) and the fixed magnetic ring array (4) are composed of multiple radially uniformly magnetized tile-shaped magnets spliced ​​together. The number of tile-shaped magnets can be 4, 5, 6, 8, 10, 12 or 15, and the gap between adjacent tile-shaped magnets does not exceed 3°.

7. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1, characterized in that: The moving magnetic ring mounting component (3), the fixed magnetic ring fixing component (5), the moving magnetic ring positioning component (16), and the fixed magnetic ring positioning component (17) are made of non-magnetic or weakly magnetic aluminum alloy or titanium alloy metal materials.

8. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 1 or 5, characterized in that: The number of throttle orifices (14) between adjacent auxiliary gas tanks (12) are different and their positions do not overlap.

9. The high-end instrument equipment heavy-duty precision gas-magnetic composite low-frequency isolation micro-vibrator according to claim 8, characterized in that: The throttling orifice (14) is triangular, circular, pentagonal, or other polygonal in shape.

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