A precision active vibration damper compatible with vacuum environment

Abstract

The present application belongs to the field of ultra-precision vibration reduction, and discloses a precision active vibration reducer compatible with a vacuum environment, comprising: a top plate, a bottom plate, and a vibration reduction unit, wherein the vibration reduction unit comprises a passive vibration reduction unit and an active vibration reduction unit connected in parallel, the active vibration reduction unit being arranged between the top plate and the bottom plate and being located outside the air spring, and the passive vibration reduction unit comprising a coaxial and vertically arranged air spring and a magnetic negative stiffness spring; the air spring comprises a main air chamber, the bottom of the main air chamber being connected to a metal sealing bellows, the top of the main air chamber being flexibly connected to the top plate; the bottom end of the metal sealing bellows being sealed and fixed to the bottom plate, so that the main air chamber becomes a vacuum-sealed cavity; the magnetic negative stiffness spring being arranged in the air spring, and its top end being fixed to the upper wall of the cavity, and its bottom end being flexibly connected to the bottom plate. The present application has excellent vibration isolation performance and good adaptability to a vacuum environment, and can meet the vibration isolation requirements of equipment such as EUV lithography machines.

Description

Technical Field

[0001] The present application belongs to the field of ultra-precision vibration reduction technology, and more specifically, relates to a precision active vibration reducer compatible with a vacuum environment. Background Art

[0002] In the field of ultra-precision manufacturing and testing, with the increasing development of precision manufacturing and testing equipment, the requirements for vibration suppression are becoming increasingly stringent. Vibration suppression is primarily divided into isolating foundation vibration and suppressing the load platform's own vibration. Foundation vibration is typically isolated using purely passive, semi-active, or active methods; load platform vibration is typically suppressed using active control. Common vibration absorbers typically use metal springs, air springs, or air bearings as vibration suppression elements, supplemented by electric actuators for active vibration control. Vibration isolation theory states that vibration isolation is effective only when the external interference frequency is greater than the natural frequency of the vibration isolation system. Therefore, to achieve excellent vibration isolation across a wide frequency range, it is necessary to reduce system stiffness and lower the natural frequency. Currently, a promising solution for precision vibration suppression is to introduce a negative stiffness mechanism into the vibration isolation system. This mechanism offsets the positive stiffness of the positive stiffness elements, thereby achieving a lower natural frequency. Alternatively, air bearings can be used to achieve quasi-zero stiffness vibration isolation, similarly achieving an extremely low natural frequency.

[0003] Chinese patent document CN201110248147.9 discloses an ultra-low-frequency precision active vibration damper. This damper comprises a passive vibration damping unit consisting of a negative stiffness mechanism and an air spring in parallel. The negative stiffness mechanism is a compression rod structure composed of a leaf spring, a hinge, and a rigid rod. The parallel combination of positive and negative stiffnesses enables the damper to possess both high load-bearing capacity and extremely low stiffness, significantly reducing its natural frequency. However, due to the high leakage rate of the air spring and the significant outgassing of the rubber mold used for the air spring, the active vibration damper disclosed in this patent cannot be used in a vacuum environment. Chinese patent document CN201210578292.8 discloses a zero-stiffness vibration isolator with angular decoupling using a sliding spherical bearing. The isolator body is lubricated and supported by an air bearing surface and decoupled by the sliding spherical bearing. This achieves zero stiffness in both vertical and horizontal directions, high positioning accuracy, and angular decoupling, resulting in an extremely low natural frequency and outstanding low-frequency / ultra-low-frequency vibration isolation performance. However, since the air bearing requires real-time release of gas, the vibration isolator provided by this patent is not suitable for a vacuum environment.

[0004] In summary, while existing technical solutions can meet the needs of ultra-low-frequency vibration reduction and provide a sufficiently quiet operating environment for precision manufacturing and testing equipment in atmospheric environments, existing vibration dampers are not suitable for equipment that requires vacuum operation, such as EUV lithography equipment. Therefore, a precision vibration damper compatible with vacuum environments is needed. Summary of the Invention

[0005] In view of the defects of the existing technology, the purpose of this application is to provide a precision active vibration damper compatible with a vacuum environment, aiming to solve the problem that the existing vibration dampers cannot be used in a vacuum environment.

[0006] To achieve the above-mentioned objectives, the present application provides a precision active vibration damper compatible with a vacuum environment, comprising: a top plate, a bottom plate and a vibration damping unit, the vibration damping unit comprising a passive vibration damping unit and an active vibration damping unit connected in parallel, the active vibration damping unit being arranged between the top plate and the bottom plate and outside the air spring, the passive vibration damping unit comprising a coaxial and vertically arranged air spring and a magnetic negative stiffness spring; the air spring comprising a main air chamber, the bottom of the main air chamber being connected to a metal sealing bellows, the top of the main air chamber being flexibly connected to the top plate; the bottom end of the metal sealing bellows being sealed and fixed to the bottom plate, so that the main air chamber forms a first vacuum sealed cavity; the magnetic negative stiffness spring is located in the air spring, the top end of which is fixed to the upper wall of the first vacuum sealed cavity, and the bottom end of which is flexibly connected to the bottom plate.

[0007] The active vibration damper provided by this application is loaded with air springs and supplemented by magnetic negative stiffness springs. It can simultaneously suppress micro-vibrations in high, medium, and low frequency bands, providing a stable operating environment for precision equipment. In addition, the vibration damper is provided with a vacuum sealing structure. The high-pressure gas inside the air spring will not leak into the environment, and the components inside the air spring will not release harmful gases such as hydrocarbons into the external environment. In short, the precision active vibration damper provided by this application has excellent vibration isolation performance and good adaptability to vacuum environments, meeting the vibration isolation requirements of equipment such as EUV lithography machines.

[0008] Furthermore, the shock absorber also includes a vacuum sealing assembly, which includes a top plate sealing plate, a metal sealing shell, a bottom plate sealing plate and a flange sealing plate; the metal sealing shell is a hollow cylindrical structure, the upper end of which is fixed to the top plate, and the lower end of which is fixed to the bottom plate to form an installation cavity; a through hole is opened on the bottom plate for supplying air to the inside of the air spring, the flange sealing plate is fixed at the through hole, the top plate sealing plate is fixed to the outside of the top plate, and the bottom plate sealing plate is fixed to the outside of the bottom plate, so that the installation cavity forms a second vacuum sealing cavity, and the vibration damping unit is fixed in the second vacuum sealing cavity.

[0009] Furthermore, a first corrugated structure is provided on the circumference of one end of the metal sealing shell close to the bottom plate.

[0010] Furthermore, the magnetic negative stiffness spring is a three-dimensional magnetic negative stiffness mechanism, and the three-dimensional magnetic negative stiffness mechanism includes a vertical magnetic negative stiffness mechanism, a horizontal magnetic negative stiffness mechanism and a vertical guided air flotation. The vertical magnetic negative stiffness mechanism and the horizontal magnetic negative stiffness mechanism are connected side by side, the top of the horizontal magnetic negative stiffness mechanism is fixed on the top plate, and the bottom of the vertical magnetic negative stiffness mechanism is fixed on the bottom plate; the vertical guided air flotation includes an air float and an air flotation stator that are connected to each other, the air float is connected to the bottom of the horizontal magnetic negative stiffness mechanism, and the bottom of the air flotation stator is connected to the bottom plate.

[0011] Furthermore, a second corrugated structure is provided in the circumferential direction of one end of the metal sealing shell close to the top plate.

[0012] Furthermore, the magnetic negative stiffness spring includes a magnetic negative stiffness stator bracket, a first annular permanent magnet, a magnetic negative stiffness mover bracket and a second annular permanent magnet, the magnetic negative stiffness stator bracket is a cylinder, and multiple first annular permanent magnets are evenly fixed on the cylinder to form a columnar stator permanent magnet assembly, and adjacent first annular permanent magnets are not connected; the magnetic negative stiffness mover bracket is cylindrical, and multiple second annular permanent magnets are coaxial and evenly fixed on the inner wall of the magnetic negative stiffness stator bracket to form a cylindrical mover permanent magnet assembly; the mover permanent magnet assembly is tightly mounted and fixed on the outside of the stator permanent magnet assembly, and the second annular permanent magnets and the first annular permanent magnets correspond one to one.

[0013] Furthermore, the active vibration reduction unit includes: a first sensing and measuring module, a vertical Lorentz linear motor and a horizontal Lorentz linear motor arranged between the metal sealed shell and the air spring, and the first sensing and measuring module includes a horizontal displacement sensor, a vertical displacement sensor, a horizontal velocity sensor and a vertical velocity sensor arranged near the top plate.

[0014] Furthermore, the shock absorber also includes a horizontal leaf spring adjustment mechanism and a second sensing and measuring module. The horizontal leaf spring adjustment mechanism is fixed on the base plate and is located outside the air spring and is connected in parallel with the air spring. The second sensing and measuring module is arranged inside the air spring and close to the top plate. Preferably, the magnetic negative stiffness spring is an adjustable magnetic negative stiffness spring.

[0015] Furthermore, the horizontal leaf spring adjustment mechanism includes: a first double leaf spring mechanism, a second double leaf spring mechanism, a first flexible pull rod and a second flexible pull rod, the first double leaf spring mechanism and the second double leaf spring mechanism are both vertically arranged, and the first flexible pull rod and the second flexible pull rod are both horizontally arranged; the bottom end of the first double leaf spring mechanism is fixed to a corner of the bottom plate, and the top end thereof is connected to one end of the first flexible pull rod and then fixed to the top plate; the bottom end of the second leaf spring structure is fixed to the other corner of the bottom plate, and the top end thereof is connected to one end of the second flexible pull rod and then fixed to the top plate.

[0016] Furthermore, the second sensing and measuring module includes a vertical displacement sensor, a horizontal displacement sensor, a horizontal speed sensor and a vertical speed sensor, a displacement sensor bracket and a speed sensor bracket; the displacement sensor bracket is vertically fixed on the base plate, and the vertical displacement sensor and the horizontal displacement sensor are fixed to the upper part of the displacement sensor bracket; the speed sensor bracket is fixed to the inner side wall of the top end of the air spring, and the horizontal speed sensor and the vertical speed sensor are arranged on the speed sensor bracket.

[0017] In general, the above technical solutions conceived by this application have the following technical advantages compared with the existing technologies:

[0018] 1. The shock absorber of the present application adopts air spring bearing, supplemented by magnetic negative stiffness spring, which can simultaneously suppress micro-vibrations in high, medium and low frequency bands, providing a stable operating environment for precision equipment; at the same time, the air spring and the top plate and bottom plate cooperate to form a vacuum sealing structure that accommodates the magnetic negative stiffness spring, so that the high-pressure gas inside the air spring will not leak into the environment, and the components inside the air spring are prevented from releasing harmful gases such as hydrocarbons into the environment; overall, the precision active shock absorber of the present application has excellent vibration isolation performance and good adaptability to vacuum environment, meeting the vibration isolation requirements of EUV lithography machines and other equipment.

[0019] 2. The air spring of the shock absorber of the present application is also covered with a metal sealing shell to form another layer of vacuum sealing structure. The design of the double-layer vacuum sealing structure can prevent the high-pressure gas inside the air spring from leaking into the environment, and can also prevent the internal components of the shock absorber from releasing harmful gases into the air or vacuum environment, and has better adaptability to vacuum environment.

[0020] 3. The number and local structure of the corrugated pleat structure of the metal bellows sealing tube connected to the air spring of the shock absorber of the present application can be changed, which can change the horizontal stiffness of the air spring; at the same time, the shock absorber can also change the horizontal stiffness of the outer vacuum sealing structure by changing the number and local structure of the corrugated pleat structure on the metal sealing shell; when the shock absorber has positive stiffness in the horizontal direction, it is necessary to use the horizontal magnetic negative stiffness mechanism in the three-dimensional magnetic negative stiffness mechanism to reduce the horizontal natural frequency of the shock absorber; when the shock absorber as a whole has negative stiffness in the horizontal direction, it is necessary to use a horizontal leaf spring adjustment mechanism to ensure the stability of the vibration isolator.

[0021] 4. The shock absorber of the present application includes a three-dimensional magnetic negative stiffness mechanism, which is composed of a vertical magnetic negative stiffness mechanism and a horizontal magnetic negative stiffness mechanism. The vertical magnetic negative stiffness mechanism and the horizontal magnetic negative stiffness mechanism are detachably connected through vertical guided air floatation. Therefore, their structure can be changed according to different usage requirements. For example, the horizontal magnetic negative stiffness mechanism in the three-dimensional magnetic negative stiffness mechanism can be removed, and only the vertical magnetic negative stiffness mechanism can be retained to cope with more diverse usage scenarios. In addition, the vertical magnetic negative stiffness mechanism can also be configured as an adjustable type, and the shock absorber structure is more varied.

[0022] 5. The vibration absorber of the present application reduces the natural frequency of the vibration absorber by introducing a three-dimensional magnetic negative stiffness mechanism. Compared with negative stiffness mechanisms such as an inverted pendulum mechanism and an Euler beam, the three-dimensional magnetic negative stiffness mechanism has a compact and frictionless structure and better vibration isolation performance.

[0023] 6. The lower part of the main air chamber of the air spring used in the shock absorber of this application is connected to a metal sealing bellows, which has a longer service life than the traditional rubber sealing membrane; it also takes into account the ultra-low frequency vibration isolation performance and adaptability to the vacuum environment, and can be used in both atmospheric and vacuum environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a three-dimensional schematic diagram of the double-sealed precision active vibration absorber provided in Example 1 of the present application;

[0025] Figure 2 This is a three-dimensional schematic diagram of the internal structure of the precision active vibration absorber provided in Example 1 of the present application;

[0026] Figure 3 Schematic diagram of the internal cross-sectional structure of the precision active vibration absorber provided in Example 1 of the present application;

[0027] Figure 4 This is a schematic diagram of the explosion structure of the precision active vibration absorber provided in Example 1 of the present application;

[0028] Figure 5 This is a schematic diagram of the explosion structure of the magnetic negative stiffness spring provided in Example 1 of the present application;

[0029] Figure 6 1 is a schematic diagram of the cross-sectional structure of the magnetic negative stiffness spring provided in Example 1 of the present application;

[0030] Figure 7 This is a schematic diagram of the double sealing groove structure provided in Example 1 of the present application;

[0031] Figure 8 This is a three-dimensional schematic diagram of a double-sealed precision active vibration absorber provided in Example 2 of the present application;

[0032] Figure 9 This is a schematic structural diagram of a precision active vibration absorber without a metal sealed housing provided in Example 2 of the present application;

[0033] Figure 10 Schematic diagram of the three-dimensional magnetic negative stiffness spring structure provided in Example 2 of the present application;

[0034] Figure 11 This is a schematic diagram of the vertically guided air flotation structure provided in Example 2 of the present application;

[0035] Figure 12 This is a three-dimensional schematic diagram of a single-layer sealed precision active vibration absorber provided in Example 3 of this application;

[0036] Figure 13 Schematic diagram of the cross-sectional structure of the precision active vibration absorber provided in embodiment 3 of the present application;

[0037] Figure 14 This is a schematic diagram of the structure and installation position of the horizontal leaf spring adjustment mechanism provided in Example 3 of this application;

[0038] Figure 15 This is a schematic diagram of the structure and installation position of the second sensing measurement module provided in embodiment 3 of this application.

[0039] In all the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-top plate, 11-first sealing groove, 12-second sealing groove, 13-first flexible block, 14-second flexible block, 15-sealing long groove, 151-vacuum chamber, 152-exhaust pipe; 2-bottom plate, 21-connecting hole, 22-bottom plate frame, 23-bottom plate sealing plate, 24-flexible rod, 25-through hole; 3-vacuum sealing assembly, 31-top plate sealing plate, 32-metal sealing shell, 3 21-first corrugated pleated structure, 322-second corrugated pleated structure, 33-bottom plate sealing plate, 34-flange sealing plate, 341-aviation plug interface, 342-quick-tightening interface, 343-water-gas sealing bellows; 4-air spring, 41-main air chamber, 42-metal sealing bellows; 5-magnetic negative stiffness spring, 51a-vertical magnetic negative stiffness mechanism, 51b-horizontal magnetic negative stiffness mechanism, 51c-vertical guide air float, 51d-adapter plate, 51c1-air float, 51c2- Air-floating stator, 52a-stator permanent magnet assembly, 52a1-magnetic negative stiffness stator bracket, 52a2-first annular permanent magnet, 52a3-first washer, 52b-motor permanent magnet assembly, 52b1-magnetic negative stiffness mover bracket, 52b2-second annular permanent magnet, 52b3-second washer; 6-first sensing measurement module, 6a-vertical Lorentz linear motor, 6b-horizontal displacement sensor, 6c-horizontal velocity sensor, 6d-vertical displacement sensor, 6e-vertical velocity sensor Sensor, 6f-horizontal Lorentz linear motor; 7-horizontal leaf spring adjustment mechanism, 71-first leaf spring, 72-first flexible pull rod, 73-first leaf spring clamping assembly, 74-second leaf spring, 75-second flexible pull rod, 76-fixed block; 8-second sensing measurement module, 8a-displacement sensor bracket, 8b-vertical displacement sensor, 8c-horizontal speed sensor, 8d-horizontal displacement sensor, 8e-vertical speed sensor, 8f-speed sensor bracket, 9-column. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0041] Example 1

[0042] This embodiment provides a vacuum environment compatible precision active vibration damper, such as Figure 1-4As shown, it includes a top plate 1, a bottom plate 2, a vacuum sealing assembly 3 and a vibration reduction unit, wherein: the vibration reduction unit includes a passive vibration reduction unit and an active vibration reduction unit connected in parallel, and the passive vibration reduction unit includes a coaxial and vertically arranged air spring 4 and a magnetic negative stiffness spring 5; the upper part of the air spring 4 is a cylindrical cavity with an open bottom end, and a first flexible block 13 is provided between the top of the cylindrical cavity and the top plate 1, and the first flexible block 13 is connected to the air spring 4 and the top plate 1 by screws. The air spring 4 includes an upper main air chamber 41, and the bottom end of the main air chamber 41 is also connected to a welded metal sealing bellows 42. The metal sealing bellows 42 serves as an elastic sealing membrane that can adapt to a vacuum environment; specifically, the lower end face of the air spring 4 and the upper end face of the metal bellows 41 are fixedly connected by a plurality of bolts in a circumferential array. The bottom opening of the metal sealing bellows 42 is fixed to the base plate 2 via a plurality of bolts arranged in a circumferential array, forming an inverted pendulum mechanism with a sealed internal space within the air spring 4. The main air chamber 41 forms a first vacuum-sealed cavity. A magnetic negative spring 5 is disposed within the first vacuum-sealed cavity, with its top end fixed to the upper wall of the cavity. The bottom end of the magnetic negative spring 5 is flexibly connected to the base plate 2. Specifically, a second flexible block 14 is disposed between the bottom end of the magnetic negative spring 5 and the base plate 2. The second flexible block 14 is fixedly connected to the base plate 2 via screws, similarly forming an inverted pendulum mechanism.

[0043] The aforementioned vacuum sealing assembly 3 includes a top plate sealing plate 31, a metal sealing shell 32, a bottom plate sealing plate 33 and a flange sealing plate 34; the metal sealing shell 32 is a hollow cylindrical structure, the upper end of which is fixed on the top plate 1, and the lower end of which is fixed on the bottom plate 2 to form an installation cavity; a through hole 25 is opened on the bottom plate 2 to supply air to the internal cavity of the air spring of the shock absorber, the flange sealing plate 34 is fixed at the through hole 25, the top plate sealing plate 31 is fixed to the outside of the top plate 1, and the bottom plate sealing plate 33 is fixed to the outside of the bottom plate 2, so that the installation cavity forms a second vacuum sealing cavity, and the vibration damping unit is fixed in the second vacuum sealing cavity.

[0044] Specifically, the top plate sealing plate 31 is fixedly connected to the top plate 1 via multiple M6 vacuum bolts arranged in a rectangular array. A first sealing groove 11 is provided between the top plate sealing plate 31 and the top plate 1, arranged on the top plate 1 and the bottom plate 2 to achieve sealing. Two first sealing grooves 11 are symmetrically arranged around the periphery of the bottom surface of the top plate 1. Four columns 9 are also provided between the top plate sealing plate 31 and the bottom plate 2 for support. Each column 9 is fixed to the top plate 1 via a corresponding limit screw 10 and is also fixedly connected to the bottom plate 2 of the shock absorber via screws. Due to the limiting effect of the four columns and limit screws, the vertical and horizontal displacement range of the top plate 1 is ±1mm. The bottom plate sealing plate 33 is embedded in the middle of the bottom plate 2 and fixedly connected to the bottom plate 2 via screws. A second sealing groove 12 is provided between the bottom plate sealing plate 33 and the bottom plate 2. The second sealing groove 12 may also be two, symmetrically arranged around the periphery of the bottom plate 2.

[0045] The aforementioned top plate sealing plate 31 is also provided with M10 threaded holes arranged in an array, through which the shock absorber can be bolted to the dynamic frame at the external load end it carries. Connection holes 21 are provided on the four corners of the bottom plate 2, through which it can be connected to the fixed frame at the external load end; the flange sealing plate 34 is integrated with 3 aviation plug interfaces 341 and 4 quick-screw interfaces 342, the aviation plug interfaces 341 can be used to power the shock absorber, and the quick-screw interfaces 342 can be used to supply air, water, etc. to the inside of the air spring 4, and a water-gas sealing bellows 343 is also fixed to the outer edge of the quick-screw interface 342.

[0046] In this embodiment, the aforementioned metal sealed shell 32 is provided with a first annular corrugated structure 321 on the circumference of one end close to the bottom plate 2, and the metal sealed shell 32 is also provided with a second annular corrugated structure 322 on the circumference of one end close to the top plate 1. The first corrugated structure 321 and the second corrugated structure 322 are both sealing corrugated structures. The metal sealed shell 32 is used to separate the internal components of the shock absorber from the external vacuum environment to prevent internal gas and hydrocarbons from leaking into the vacuum environment. The function of the corrugated structure thereon is to change the horizontal stiffness of the air spring and the outer sealing structure.

[0047] In this embodiment, Figure 5-6As shown, the aforementioned magnetic negative stiffness spring 5 includes a magnetic negative stiffness stator bracket 52a1, a first annular permanent magnet 52a2, a magnetic negative stiffness mover bracket 52b1 and a second annular permanent magnet 52b2. The magnetic negative stiffness stator bracket 52a1 is a cylinder with a base. The three first annular permanent magnets 52a2 are coaxial and evenly arranged, and are fixed to the magnetic negative stiffness stator bracket 52a1 with a high-strength structural rubber sleeve to form a columnar stator permanent magnet assembly 52a, and a first gasket 52a3 of the same thickness is provided between adjacent first annular permanent magnets 52a2. The magnetic negative stiffness mover bracket 52b1 is cylindrical, and three second annular permanent magnets 52b2 are coaxially and evenly and tightly fixed on its inner wall with high-strength structural adhesive, and second washers 52b3 of the same thickness are arranged between adjacent second annular permanent magnets 52b2 at a certain distance, thereby forming a cylindrical mover permanent magnet assembly 52b; the mover permanent magnet assembly 52a is tightly mounted and fixed on the outside of the stator permanent magnet assembly 52b, and the second annular permanent magnets 52b2 and the first annular permanent magnets 52a2 correspond one to one.

[0048] In this embodiment, the height of the aforementioned second annular permanent magnet 52b2 is 1 to 2 times, such as 1.5 times, the height of the first annular permanent magnet 52a2; the magnetization directions of all permanent magnets are vertical, and along the vertical direction, the magnetization directions of any two adjacent second annular permanent magnets 52b2 or first annular permanent magnets 52a2 are opposite; along the horizontal direction, the magnetization directions of any two adjacent second annular permanent magnets 52b2 and first annular permanent magnets 52a2 are the same.

[0049] In this embodiment, the aforementioned active vibration reduction unit includes a first sensing and measuring module 6, a vertical Lorentz linear motor 6a and a horizontal Lorentz linear motor 6f arranged between the metal sealed shell 32 and the air spring 4. The first sensing and measuring module 6 includes a horizontal displacement sensor 6b, a vertical displacement sensor 6d, a horizontal velocity sensor 6c and a vertical velocity sensor 6e arranged near the top plate 1.

[0050] Specifically, the moving parts of the vertical Lorentz linear motor 6a and the horizontal Lorentz linear motor 6f are fixedly connected to the top plate 1 by screws, and their stator parts are fixedly connected to the bottom plate 2 by screws; the horizontal displacement sensor 6b and the vertical displacement sensor 6d are connected to the bottom plate 2 by a fixed bracket, and the horizontal speed sensor 6c and the vertical speed sensor 6e are fixedly connected to the top plate 1 by another fixed bracket.

[0051] In this embodiment, the first sealing groove 11 and the second sealing groove 12 can also be a high vacuum double sealing groove structure, such as Figure 7As shown, the double sealing groove structure includes two parallel sealing long grooves 15 and a vacuum chamber 151. The vacuum chamber 151 is arranged between the two sealing grooves, and the vacuum chamber 151 is connected to the air supply hole arranged on the bottom plate 2 through an exhaust pipe 152, and is connected to the external vacuum equipment through a quick-tighten joint arranged on the flange sealing plate 34 to ensure that a vacuum state can be achieved.

[0052] The vibration damping principle of the shock absorber in this embodiment is as follows: the air spring 4 is arranged in an inverted pendulum configuration, providing negative stiffness in the horizontal direction and high load-bearing capacity and positive stiffness in the vertical direction. The magnetic negative stiffness spring 5 provides positive horizontal stiffness and negative vertical stiffness. Due to the parallel connection of positive and negative stiffness, the shock absorber achieves low natural frequencies in both the vertical and horizontal directions. The vacuum seal assembly 3 isolates the internal world of the shock absorber from the external vacuum environment, thereby ensuring vacuum compatibility.

[0053] Example 2

[0054] This embodiment provides a vacuum environment compatible precision active vibration damper, such as Figure 8 and Figure 9 As shown, the difference from Example 1 is that a first annular corrugated structure 321 is provided at one end of the metal sealing shell 32 close to the bottom plate 2, but the second corrugated structure 322 of the metal sealing shell 32 close to the top plate 1 is removed. The advantage of this design is that the single-layer corrugated structure has higher structural stiffness, and is always positive stiffness in the horizontal direction, so it is more stable.

[0055] In this embodiment, Figure 10 As shown, the aforementioned magnetic negative stiffness spring 5 is a three-dimensional magnetic negative stiffness mechanism, which includes a vertical magnetic negative stiffness mechanism 51a, a horizontal magnetic negative stiffness mechanism 51b and a vertical guiding air float 51c. The vertical magnetic negative stiffness mechanism 51a and the horizontal magnetic negative stiffness mechanism 51b are connected side by side with an upper and lower offset. The top of the horizontal magnetic negative stiffness mechanism 51b is fixed on the top plate 1, and the bottom of the vertical magnetic negative stiffness mechanism 51a is fixed on the bottom plate 2; the vertical guiding air float 51c includes an air float 51c1 and an air float stator 51c2 connected to each other, the air float 51c1 is detachably fixed to the bottom of the horizontal magnetic negative stiffness mechanism 51b, and the bottom of the air float stator 51c2 is fixed on the bottom plate 2; in a preferred embodiment, the horizontal magnetic negative stiffness mechanism 51b can also be removed, leaving only the vertical magnetic negative stiffness mechanism 51a, to cope with different application scenarios.

[0056] Specifically, the vertical magnetic negative stiffness mechanism 51a provides negative stiffness in the vertical direction and offsets the vertical positive stiffness of the air spring 4. The specific structure of the vertical magnetic negative stiffness mechanism 51a is the existing technology and will not be repeated here. For details, please refer to the introduction in Chinese patent document CN114151488A; the horizontal magnetic negative stiffness mechanism 51b provides negative stiffness in the horizontal direction and offsets the horizontal positive stiffness of the air spring 4. The specific structure of the horizontal magnetic negative stiffness mechanism 51b is the existing technology and will not be repeated here. For details, please refer to the detailed description in Chinese patent document CN116677738A.

[0057] More specifically, the vertical magnetic negative stiffness mechanism 51a and the horizontal magnetic negative stiffness mechanism 51b are fixedly connected via an adapter plate 51d, and the adapter plate 51d is stepped, so that the vertical magnetic negative stiffness mechanism 51a and the horizontal magnetic negative stiffness mechanism 51b are staggered up and down.

[0058] The structure of the active vibration reduction unit in this embodiment is the same as that in embodiment 1. The specific fixing method and fixing position can be the same as those in embodiment 1, and can also be changed according to the adaptability of the specific application environment.

[0059] The vibration damping principle of this embodiment's shock absorber is as follows: the sealed metal housing 32 and the first corrugated pleated structure 321 isolate the shock absorber from the external environment while acting as an air spring, providing vertical load-bearing and three-dimensional vibration isolation. Compared to Example 1, the air spring in this embodiment has a larger load-bearing area and a simpler structure. Combined with the three-dimensional magnetic negative stiffness mechanism 5, low natural frequencies in both vertical and horizontal directions are achieved.

[0060] Example 3

[0061] The vibration damper provided in this embodiment is as follows Figure 12-13 As shown, it includes a top plate 1, a bottom plate 2 and a vibration reduction unit, the vibration reduction unit includes a passive vibration reduction unit and an active vibration reduction unit connected in parallel, the bottom plate 2 includes a bottom plate frame 22 and a bottom plate sealing plate 23, the bottom plate sealing plate 23 is fixed to the bottom plate frame 22 by screws, and the through hole 25 is located on the bottom plate frame 22; the active vibration reduction unit includes the same vertical Lorentz linear motor 6a and horizontal Lorentz linear motor 6f as those in Examples 1 and 2, and their fixed positions and fixing methods are the same as those in the aforementioned Examples 1 and 2, which will not be repeated here.

[0062] The passive vibration reduction unit includes a coaxial and vertically arranged air spring 4 and a magnetic negative stiffness spring 5; the upper part of the air spring 4 is a cylindrical cavity with an open bottom end, and a first flexible block 13 is arranged between the top of the cylindrical cavity and the top plate 1 to achieve a flexible connection. The first flexible block 13 uses screws to connect the air spring 4 and the top plate 1.

[0063] Specifically, the air spring 4 includes a main air chamber 41, the lower end of the main air chamber 41 is connected to a coaxially arranged metal sealing bellows 42, and the metal sealing bellows 42 serves as an elastic sealing membrane of the air spring 4 and can adapt to a vacuum environment; more specifically, the upper end of the main air chamber 41 is closed and the lower end face is open, and the opening of the lower end face is fixedly connected to the upper end face of the metal bellows 41 by a plurality of bolts in a circular array, and the bottom end opening of the metal sealing bellows 42 is fixed to the base plate 2 by a plurality of bolts in a circular array, so that the air spring 4 forms an inverted pendulum mechanism with a closed internal space.

[0064] The magnetic negative stiffness spring 5 is arranged in the air spring 4. The magnetic negative stiffness spring 5 uses an adjustable magnetic negative stiffness mechanism, and the upper end of the adjustable magnetic negative stiffness mechanism is connected to the upper wall of the main air chamber 41 through a flexible rod 24, and its lower end is fixedly connected to the bottom plate sealing plate 23, so that the magnetic negative stiffness spring 5 becomes an inverted pendulum mechanism, which is used to offset the vertical positive stiffness of the air spring 4 and further improve the vertical vibration isolation performance. Since the adjustable magnetic negative stiffness spring is an existing technology, it will not be repeated here. Its specific structure can be referred to the record in Chinese patent document CN102808883B.

[0065] The shock absorber provided in this embodiment further includes a horizontal leaf spring adjustment mechanism 7 and a second sensor measurement module 8, such as Figure 14-15 As shown, the horizontal leaf spring adjustment mechanism 7 is fixed on the bottom plate 2 and connected in parallel with the air spring 4 ; the second sensing measurement module 8 is arranged in the air spring 4 and close to the top plate 1 .

[0066] The aforementioned horizontal leaf spring adjustment mechanism 7 includes a first double leaf spring mechanism and a second double leaf spring mechanism arranged vertically, and also includes a first flexible pull rod 72 and a second flexible pull rod 75 arranged horizontally.

[0067] The first double-leaf spring mechanism includes two first leaf springs 71 arranged in parallel and opposite to each other. The two ends of the two first leaf springs 71 are fixed together with fixing blocks 76, and the first double-leaf spring mechanism is vertically fixed on a corner of the base plate 2. A fixing rod 77 is also connected to the fixing block 76 at the upper end of the first double-leaf spring mechanism. The fixing rod 77 is fixedly connected to one end of the first flexible pull rod 72, and the connection between the fixing rod 77 and the first flexible pull rod 72 is also fixed on the top plate 1; a first leaf spring clamping assembly 73 that can slide up and down along the first leaf spring 71 is provided in the middle of the first double-leaf spring mechanism.

[0068] The first leaf spring clamping assembly 73 is composed of three leaf spring clamping blocks respectively arranged on the outside of the two first leaf springs 71 and between the two. Corresponding bolt holes are opened on the three leaf spring clamping blocks. Bolts are passed through the bolt holes of the three to fix the three together. A sliding groove is provided between the two leaf spring clamping blocks, so that the first leaf spring clamping assembly 73 can slide up and down along the first double leaf spring mechanism.

[0069] The second double-leaf spring mechanism includes two parallel, spaced-apart second leaf springs 74. These two second leaf springs 74 are vertically fixed to the other corner of the bottom plate 2, adjacent to the first double-leaf spring 71. The upper ends of the second leaf springs 74 are also connected to one end of a second flexible pull rod 75 via a fixing rod 77, and the connection between the two is also fixed to the top plate 1. The other end of the first flexible pull rod 72 is fixedly connected to the other end of the second flexible pull rod 75.

[0070] The aforementioned second sensing and measuring module 8 includes a vertical displacement sensor 8b (a displacement sensor arranged in the vertical direction), a horizontal displacement sensor 8d (a displacement sensor arranged in the horizontal direction), a horizontal speed sensor 8c (a speed sensor arranged in the horizontal direction) and a vertical speed sensor 8e (a speed sensor arranged in the vertical direction), a displacement sensor bracket 8a and a speed sensor bracket 8f; the displacement sensor bracket 8a is vertically fixed on the base plate 2, the vertical displacement sensor 8b and the horizontal displacement sensor 8d are fixed to the upper part of the displacement sensor bracket 8a; the speed sensor bracket 8f is fixed on the inner side wall of the top end of the air spring 4, and the horizontal speed sensor 8c and the vertical speed sensor 8e are arranged on the speed sensor bracket 8f.

[0071] The vibration reduction principle of the shock absorber of this embodiment is as follows: the air spring 4 is arranged in an inverted pendulum to provide negative stiffness in the horizontal direction and large bearing capacity and positive stiffness in the vertical direction; the adjustable magnetic negative stiffness spring 5 provides vertical negative stiffness; and the horizontal leaf spring adjustment mechanism 7 provides horizontal positive stiffness. Based on the characteristics of positive and negative stiffness in parallel, the shock absorber can achieve low natural frequency in the vertical and horizontal directions. Unlike Examples 1 and 2, Example 3 does not provide a vacuum sealing component 3, so it is necessary to arrange the second sensor measurement module 8 inside the air spring 4. The vertical Lorentz linear motor 6a and the horizontal Lorentz linear motor 6f are located outside the air spring 4 and are therefore directly exposed to the vacuum environment. Therefore, the motor selected in this embodiment needs to meet vacuum compatibility.

[0072] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0073] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0074] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0075] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0076] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A vacuum environment compatible precision active vibration damper, characterized in that: include: A top plate (1), a bottom plate (2), a vibration reduction unit and a vacuum sealing assembly (3), wherein the vibration reduction unit comprises a passive vibration reduction unit and an active vibration reduction unit connected in parallel, wherein the passive vibration reduction unit comprises a coaxial and vertically arranged air spring (4) and a magnetic negative stiffness spring (5), and the active vibration reduction unit is arranged between the top plate (1) and the bottom plate (2) and is located outside the air spring (4); the air spring (4) comprises a main air chamber (41), the bottom of the main air chamber (41) is connected to a metal sealing bellows (42), and the top end of the main air chamber (41) is flexibly connected to the top plate (1); the bottom end of the metal sealing bellows (42) is sealed and fixed on the bottom plate (2), so that the main air chamber (41) forms a first vacuum sealing cavity; the magnetic negative stiffness spring (5) is located in the air spring (4), the top end of which is fixed on the upper wall of the first vacuum sealing cavity, and the bottom end of which is connected to the bottom plate (2 ) flexible connection; the vacuum sealing assembly (3) includes a top plate sealing plate (31), a metal sealing shell (32), a bottom plate sealing plate (33) and a flange sealing plate (34); the metal sealing shell (32) is a hollow cylindrical structure, the upper end of which is fixed on the top plate (1), and the lower end of which is fixed on the bottom plate (2) to form a mounting cavity, and the metal sealing shell (32) is provided with a first corrugated pleat structure (321) in the circumferential direction at one end close to the bottom plate (2); a through hole (25) for supplying air to the inside of the air spring (4) is opened on the bottom plate (2), the flange sealing plate (34) is fixed at the through hole (25), the top plate sealing plate (31) is fixed to the outside of the top plate (1), and the bottom plate sealing plate (33) is fixed to the outside of the bottom plate (2), so that the mounting cavity forms a second vacuum sealing cavity, and the vibration reduction unit is fixed in the second vacuum sealing cavity.

2. A vacuum environment compatible precision active vibration damper according to claim 1, characterized in that: The magnetic negative stiffness spring (5) is a three-dimensional magnetic negative stiffness mechanism, comprising a vertical magnetic negative stiffness mechanism (51a), a horizontal magnetic negative stiffness mechanism (51b) and a vertical guide air float (51c); the vertical magnetic negative stiffness mechanism (51a) and the horizontal magnetic negative stiffness mechanism (51b) are staggeredly connected; the top of the horizontal magnetic negative stiffness mechanism (51b) is fixed on the top plate (1), and the bottom of the vertical magnetic negative stiffness mechanism (51a) is fixed on the bottom plate (2); the vertical guide air float (51c) comprises an air float (51c1) and an air float stator (51c2) connected to each other; the air float (51c1) is connected to the bottom of the horizontal magnetic negative stiffness mechanism (51b), and the bottom of the air float stator (51c2) is connected to the bottom plate (2).

3. The vacuum environment compatible precision active vibration damper according to claim 1, characterized in that: A second corrugated structure (321) is provided in the circumferential direction of one end of the metal sealing shell (32) close to the top plate (1).

4. The vacuum environment compatible precision active vibration damper according to claim 3, characterized in that: The magnetic negative stiffness spring (5) comprises a magnetic negative stiffness stator bracket (52a1), a first annular permanent magnet (52a2), a magnetic negative stiffness mover bracket (52b1) and a second annular permanent magnet (52b2), wherein the magnetic negative stiffness stator bracket (52a1) is a cylinder, and a plurality of the first annular permanent magnets (52a2) are evenly and fixedly sleeved on the cylinder to form a columnar stator permanent magnet assembly (52a), and adjacent first annular permanent magnets (52a2) are not aligned. The magnetic negative stiffness mover bracket (52b1) is cylindrical, and a plurality of the second annular permanent magnets (52b2) are coaxially and evenly fixed on the inner side wall of the magnetic negative stiffness stator bracket (52b1) to form a cylindrical mover permanent magnet assembly (52b); the mover permanent magnet assembly (52b) is tightly sleeved and fixed on the outside of the stator permanent magnet assembly (52a), and the second annular permanent magnets (52b2) and the first annular permanent magnets (52a2) correspond one to one.

5. A vacuum environment compatible precision active vibration damper according to any one of claims 2 to 4, characterized in that: The active vibration reduction unit comprises: a first sensing and measuring module (6) arranged between a metal sealed housing (32) and an air spring (4), a vertical Lorentz linear motor (6a), and a horizontal Lorentz linear motor (6f); the first sensing and measuring module (6) comprises a horizontal displacement sensor (6b), a vertical displacement sensor (6d), a horizontal velocity sensor (6c), and a vertical velocity sensor (6e) arranged near the top plate (1).

6. The vacuum environment compatible precision active vibration damper according to claim 1, characterized in that: The shock absorber further comprises a horizontal leaf spring adjustment mechanism (7) and a second sensing and measuring module (8), wherein the horizontal leaf spring adjustment mechanism (7) is fixed on the bottom plate (2) and is located outside the air spring (4) and is connected in parallel with the air spring (4); the second sensing and measuring module (8) is arranged inside the air spring (4) and close to the top plate (1); and the magnetic negative stiffness spring (5) is an adjustable magnetic negative stiffness spring.

7. The vacuum environment compatible precision active vibration damper according to claim 6, characterized in that: The horizontal leaf spring adjustment mechanism (7) comprises: a first double leaf spring mechanism, a second double leaf spring mechanism, a first flexible pull rod (72) and a second flexible pull rod (75); the first double leaf spring mechanism and the second double leaf spring mechanism are both vertically arranged, and the first flexible pull rod (72) and the second flexible pull rod (75) are both horizontally arranged; the bottom end of the first double leaf spring mechanism is fixed to a corner of the bottom plate (2), and the top end thereof is connected to one end of the first flexible pull rod (72) and then fixed to the top plate (1); The bottom end of the second leaf spring structure is fixed to the other corner of the bottom plate (2), and the top end is connected to one end of the second flexible pull rod (75) and then fixed to the top plate (1).

8. The vacuum environment compatible precision active vibration absorber according to claim 7, characterized in that: The second sensing and measuring module (8) comprises a vertical displacement sensor (8b), a horizontal displacement sensor (8d), a horizontal speed sensor (8c), a vertical speed sensor (8e), a displacement sensor bracket (8a), and a speed sensor bracket (8f); the displacement sensor bracket (8a) is vertically fixed to the base plate (2); the vertical displacement sensor (8b) and the horizontal displacement sensor (8d) are fixed to the upper part of the displacement sensor bracket (8a); the speed sensor bracket (8f) is fixed to the inner side wall of the top end of the air spring (4); and the horizontal speed sensor (8c) and the vertical speed sensor (8e) are fixed to the speed sensor bracket (8f).

Images