Gravity acceleration measuring instrument and its vertical vibration isolation device

Abstract

This application relates to a gravity acceleration measuring instrument and its vertical vibration isolation device. The vertical vibration isolation device includes a primary vibration isolation module, which comprises two fixed structures, a connecting assembly, and a floating structure. The two fixed structures are spaced apart along the direction of gravity, and each of the two fixed structures has a first embedding groove on its side closest to each other, with a first permanent magnet disposed in each first embedding groove. The connecting assembly connects the two fixed structures so that the projections of the two first embedding grooves along the direction of gravity coincide. The floating structure is located between the two fixed structures and has a central section and at least two limiting sections. One end of each limiting section is connected to the central section, and the other end of each limiting section cooperates with the connecting assembly. A second embedding groove is formed on the central section, with a second permanent magnet disposed in the second embedding groove. The vertical vibration isolation device of this application can ensure the coaxiality of the two first permanent magnets and the second permanent magnet.

Description

Technical Field

[0001] This application relates to the field of free fall measurement technology, and in particular to gravity acceleration measuring instruments and their vertical vibration isolation devices. Background Technology

[0002] A free-fall absolute gravimeter is a high-precision instrument for measuring gravitational acceleration. Its principle involves a free-fall device undergoing free fall within a vacuum chamber, accurately measuring the time and displacement during the fall. The gravitational acceleration value can be obtained by fitting a curve of the measured displacement. During the measurement of gravitational acceleration, ground vibrations can interfere with the reference prism used to measure the displacement, thus affecting the measurement accuracy. Vertical vibration isolation devices are used to reduce the impact of ground vibrations on the reference prism, providing an inertial reference point for the system. When permanent magnet levitation technology is applied to vertical vibration isolation devices, it can effectively solve the problem of ground vibrations affecting the reference prism.

[0003] In a permanent magnet suspension structure, there is a large repulsive force between two opposing permanent magnets. When all permanent magnets are coaxial, the permanent magnets are in an unstable state. The uniform gradient magnetic field required by the vertical vibration isolation device is extremely sensitive to the position of the permanent magnets themselves and their relative positions. However, the relevant technologies cannot yet ensure the stability of the relative positions of the permanent magnets. Summary of the Invention

[0004] Therefore, it is necessary to provide a gravity acceleration measuring instrument and its vertical vibration isolation device to address the problem of not being able to ensure the stability of the relative position of permanent magnets.

[0005] A vertical vibration isolation device, the vertical vibration isolation device comprising a primary vibration isolation module, the primary vibration isolation module comprising:

[0006] Two fixed structures are arranged at intervals along the direction of gravity. A first embedding groove is opened on the side of the two fixed structures that are close to each other, and a first permanent magnet is arranged in each of the first embedding grooves.

[0007] A connecting component connects the two fixed structures such that the projections of the two first embedding slots along the direction of gravity coincide;

[0008] A floating structure is located between two fixed structures. The floating structure has a middle part and at least two limiting parts. One end of each limiting part is connected to the middle part, and the other end of each limiting part cooperates with the connecting assembly to limit the displacement of the floating structure along the direction of gravity. A second embedding groove is provided on the middle part, and a second permanent magnet is provided in the second embedding groove.

[0009] In one embodiment, the end of the limiting part away from the middle part is rolled or slidably connected to the connecting component along the direction of gravity, so that the limiting part can drive the second permanent magnet to move along the direction of gravity.

[0010] In one embodiment, one of the connecting component and the limiting portion is provided with a groove extending along the direction of gravity, and the other is provided with a longitudinal sliding limiter. The longitudinal sliding limiter is limited and engaged with the groove along a first direction, which is perpendicular to the direction of gravity.

[0011] In one embodiment, the connecting component has a groove extending in the direction of gravity, and the limiting part is provided with a longitudinal sliding limiter; the longitudinal sliding limiter includes a connecting shaft and rollers respectively disposed at both ends of the connecting shaft, and each roller is capable of rolling in the corresponding groove.

[0012] In one embodiment, the limiting part has a guide groove extending in a second direction at one end away from the middle part, and the longitudinal sliding limiter passes through the guide groove. The second direction is perpendicular to both the gravity direction and the first direction.

[0013] The floating structure is also provided with a lateral adjustment component, which is used to adjust the position of the longitudinal sliding limiter in the guide groove along the first direction.

[0014] In one embodiment, the lateral adjustment assembly includes an elastic element and a lateral adjustment bolt, the elastic element and the lateral adjustment bolt being located at opposite ends of the connecting shaft along a first direction, the end of the elastic element away from the connecting shaft abutting against the inner wall of the guide groove, and the lateral adjustment bolt being threadedly connected to the side wall of the guide groove.

[0015] In one embodiment, the floating structure includes two mutually perpendicular limiting rods, each limiting rod including a middle portion and limiting portions respectively disposed at both ends of the middle portion, and the middle portions of the two limiting rods overlap.

[0016] In one embodiment, each of the fixed structures is provided with an axial adjustment member extending along a first direction, the axial adjustment member being located on the side of the first permanent magnet away from the second permanent magnet, and the adjustment end of the axial adjustment member abutting against the first permanent magnet.

[0017] In one embodiment, each of the fixed structures is provided with a plurality of axial adjustment members, and the plurality of axial adjustment members can be adjusted individually.

[0018] In one embodiment, one end of the floating structure along the direction of gravity is connected to a counterweight mounting base, and a gravity block is disposed inside the counterweight mounting base.

[0019] In one embodiment, the vertical vibration isolation device includes a secondary vibration isolation module, which includes a mounting plate, an optical plate, and a piezoelectric actuator disposed between the mounting plate and the optical plate. The primary vibration isolation module is disposed on the optical plate. A laser is mounted on the mounting plate. A light-transmitting hole extending along the direction of gravity is opened on the optical plate. A first reflector, a second reflector, and a detector are mounted on the optical plate. A third reflector is disposed at the bottom of the floating structure.

[0020] The light emitted by the laser passes through the light-transmitting hole and is reflected by the first reflector to the second reflector. After multiple reflections between the second and third reflectors, the light then illuminates the detector.

[0021] The secondary vibration isolation module includes a control unit, which is electrically connected to the detector and the piezoelectric actuator respectively. The control unit is used to adjust the piezoelectric actuator according to the position of the light spot detected by the detector, so that the piezoelectric actuator adjusts the position of the optical plate.

[0022] A gravity acceleration measuring instrument, the gravity acceleration measuring instrument includes a reference prism and the vertical vibration isolation device, the reference prism being disposed at one end of the floating structure opposite to the direction of gravity.

[0023] The aforementioned gravity acceleration measuring instrument and its vertical vibration isolation device have two fixed structures connected by a connecting component. The projections of the two first embedding slots along the gravity direction coincide. The connecting component constrains the installation position of the two first permanent magnets, ensuring alignment of the two first permanent magnets in the gravity direction and avoiding coaxiality deviation caused by repulsive forces between the permanent magnets. Furthermore, the connecting component cooperates with the limiting part to restrict the displacement of the floating structure along the gravity direction, ensuring that the second embedding slot in the middle is always in the corresponding position of the two first embedding slots, preventing deviation of the axis between the second and first permanent magnets due to displacement of the floating structure. In other words, the vertical vibration isolation device of this application can guarantee the coaxiality of the two first and second permanent magnets, ensure the stability of the first and second permanent magnets, ensure that the magnetic field distribution meets the design requirements of the vertical vibration isolation device for a uniform gradient magnetic field, and ensure that the second permanent magnet is subjected to uniform force in space. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a vertical vibration isolation device in one embodiment.

[0025] Figure 2 This is a schematic diagram of the cross-sectional structure of two fixed structures in one embodiment.

[0026] Figure 3This is a schematic diagram of the floating structure in one embodiment.

[0027] Figure 4 This is a schematic diagram of the cross-sectional structure of the floating body structure in one embodiment.

[0028] Figure 5 This is a schematic diagram of the longitudinal sliding limiter in one embodiment.

[0029] Figure 6 As one embodiment Figure 1 A schematic diagram of the structure at point A in the middle.

[0030] Figure 7 This is a schematic diagram of the structure of the lateral adjustment component in one embodiment.

[0031] Figure 8 This is a schematic diagram of optical path propagation in one embodiment.

[0032] Reference numerals: 10, primary vibration isolation module; 100, fixed structure; 120, first permanent magnet; 130, annular cavity; 140, axial adjustment component; 200, connecting assembly; 210, limiting post; 211, groove; 220, column; 230, pressure block; 240, reinforcing plate; 300, floating structure; 320, second permanent magnet; 330, limiting rod; 331, middle part; 332, limiting part; 333, longitudinal sliding limiter; 3331, connecting shaft; 3332, roller; 3333, guide groove 3334. Mounting channel; 3335. Cover plate; 340. Lateral adjustment assembly; 341. Elastic element; 342. Lateral adjustment bolt; 360. Connecting spindle; 20. Secondary vibration isolation module; 201. Mounting plate; 202. Optical plate; 2021. Light transmission hole; 203. Piezoelectric actuator; 204. First reflector; 205. Second reflector; 206. Third reflector; 207. Detector; 400. Counterweight mounting base; 410. Mounting hole; 500. Water cooling pipe; 600. Reference prism. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0039] See Figures 1-4 An embodiment of this application provides a vertical vibration isolation device, which includes a primary vibration isolation module 10. The primary vibration isolation module 10 includes two fixed structures 100, a connecting component 200, and a floating structure 300. The two fixed structures 100 are spaced apart along the direction of gravity. A first embedding groove is provided on the side of the two fixed structures 100 that is close to each other. A first permanent magnet 120 is provided in each first embedding groove. The connecting component 200 connects the two fixed structures 100 so that the projections of the two first embedding grooves along the direction of gravity coincide. The floating structure 300 is located between the two fixed structures 100. The floating structure 300 has a middle part 331 and at least two limiting parts 332. One end of each limiting part 332 is connected to the middle part 331, and the other end of the limiting part 332 cooperates with the connecting component 200 to limit the displacement of the floating structure 300 along the direction of gravity. A second embedding groove is provided on the middle part 331, and a second permanent magnet 320 is provided in the second embedding groove.

[0040] In this embodiment, the two fixed structures 100 are connected by a connecting component 200, and the projections of the two first embedding slots along the direction of gravity coincide. The connecting component 200 is used to constrain the installation position of the two first permanent magnets 120, ensuring that the two first permanent magnets 120 are aligned in the direction of gravity, thus avoiding coaxiality deviation of the first permanent magnets 120 caused by the repulsive force between the permanent magnets. Furthermore, the connecting component 200 cooperates with the limiting part 332 to limit the displacement of the floating structure 300 along the direction of gravity, so that the second embedding slot in the middle part 331 is always in the corresponding position of the two first embedding slots, preventing the axis of the second permanent magnet 320 from deviating from that of the first permanent magnet 120 due to the offset of the floating structure 300. That is, the vertical vibration isolation device of this application can ensure the coaxiality of the two first permanent magnets 120 and the second permanent magnet 320, ensure the stability of the first permanent magnets 120 and the second permanent magnet 320, ensure that the magnetic field distribution meets the design requirements of the vertical vibration isolation device for a uniform gradient magnetic field, and ensure that the second permanent magnet 320 is subjected to uniform force in space.

[0041] In some embodiments, the end of the limiting part 332 away from the middle part 331 is rolled or slidably connected to the connecting component 200 along the direction of gravity, so that the limiting part 332 can drive the second permanent magnet 320 to move along the direction of gravity.

[0042] In some embodiments, the other end of the limiting part 332 is rolled to the connecting assembly 200 along the direction of gravity. Specifically, the other end of the limiting part 332 is provided with a roller 3332. When the second permanent magnet 320 drives the floating structure 300 to move along the direction of gravity, the roller 3332 rolls on the connecting assembly 200 to reduce the friction between the two and maximize the decoupling between the floating structure 300 and the fixed structure 100.

[0043] In some other embodiments, the other end of the limiting portion 332 is slidably connected to the connecting component 200 along the direction of gravity.

[0044] It should be noted that a smooth layer is provided on the surface of the groove 211 and / or the limiting part 332 to reduce the friction between the two and to maximize the decoupling of the floating structure 300 and the fixed structure 100.

[0045] Combination Figure 6 In some embodiments, one of the connecting component 200 and the limiting part 332 is provided with a groove 211 extending along the direction of gravity, and the other is provided with a longitudinal sliding limiter 333. The longitudinal sliding limiter 333 and the groove 211 are limited and engaged in a first direction, which is perpendicular to the direction of gravity.

[0046] For example, the first permanent magnet 120 is a ring-shaped permanent magnet structure, with the axial direction of the first permanent magnet 120 along the direction of gravity and the first direction being the radial direction of the ring-shaped permanent magnet structure.

[0047] In this embodiment, the longitudinal sliding limiter 333 and the groove 211 are engaged in a limiting cooperation along the first direction. The connecting component 200 is used to limit the position of the limiting part 332. Since there are at least two limiting parts 332, each of the at least two limiting parts 332 cooperates with the corresponding connecting component 200. This allows the position of the middle part 331 to be limited by the two limiting parts 332, so that the second permanent magnet 320 on the middle part 331 is located in the exact middle of the two first permanent magnets 120. In addition, the groove 211 extends along the first direction, so that the longitudinal sliding limiter 333 can also slide within the groove 211 along the first direction. This allows the floating structure 300 to automatically adjust its height according to the magnetic force received by the second permanent magnet 320.

[0048] Combination Figure 5Furthermore, the connecting assembly 200 has a groove 211 extending along the direction of gravity, and the limiting part 332 is provided with a longitudinal sliding limiter 333; the longitudinal sliding limiter 333 includes a connecting shaft 3331 passing through the guide groove 3333 and rollers 3332 respectively disposed at both ends of the connecting shaft 3331, so that the limiting part 332 is tumblingly connected to the connecting assembly 200. Among them, there are two rollers 3332 located at each end of the connecting shaft 3331, and the two rollers 3332 are arranged sequentially along the direction of gravity, and the connecting shaft 3331 of each roller 3332 extends along a first direction.

[0049] In some embodiments, the limiting part 332 has a guide groove 3333 extending in a second direction at one end away from the middle part 331, and the longitudinal sliding limiter 333 passes through the guide groove 3333. The second direction is perpendicular to both the gravity direction and the first direction. The floating body structure 300 is also provided with a lateral adjustment component 340, which is used to adjust the position of the longitudinal sliding limiter 333 in the guide groove 3333 along the first direction.

[0050] In this embodiment, the longitudinal sliding limiter 333 passes through the guide groove 3333, which extends along the first direction. The position of the longitudinal sliding limiter 333 in the guide groove 3333 can be adjusted by the lateral adjustment component 340. Based on this, the longitudinal sliding limiter 333 and the groove 211 cooperate along the first direction. That is, when adjusting the position of the longitudinal sliding limiter 333 in the guide groove 3333, the position of the middle part 331 can be adjusted by the limiting part 332 to ensure that the second permanent magnet 320 is always in a position that corresponds to the axis of the two first permanent magnets 120.

[0051] For example, the limiting part 332 also has an installation channel 3334 that connects the guide groove 3333 to the outside along the direction of gravity. The connecting shaft 3331 of the longitudinal sliding limiter 333 is used to enter the guide groove 3333 from the installation channel 3334. A cover plate 3335 is provided in the guide groove 3333. The cover plate 3335 is used to extend into the guide groove 3333 along the second direction to cover the connecting shaft 3331. Then, the mounting plate 201 is fixed to the connecting shaft 3331 by bolts extending along the direction of gravity, thereby realizing the installation of the longitudinal sliding limiter 333. When fixing the cover plate 3335, the normal pressure between the top plate and the connecting shaft 3331 should be as small as possible so that the connecting shaft 3331 can move freely in the guide groove 3333. The second direction is the tangential direction of the first permanent magnet 120.

[0052] Combination Figure 7For example, the lateral adjustment assembly 340 includes an elastic element 341 and a lateral adjustment bolt 342, which are located at opposite ends of the connecting shaft 3331 along a first direction. The end of the elastic element 341 away from the connecting shaft 3331 abuts against the inner wall of the guide groove 3333, and the lateral adjustment bolt 342 is threadedly connected to the side wall of the guide groove 3333. When the lateral adjustment bolt 342 is rotated, one end of the lateral adjustment bolt 342 abuts against the connecting shaft 3331, thereby causing the connecting shaft 3331 to compress the elastic element 341 to move within the guide groove 3333 along the first direction.

[0053] Combination Figure 3 In some embodiments, the floating structure 300 includes two mutually perpendicular limiting rods 330, each limiting rod 330 including a middle portion 331 and limiting portions 332 respectively disposed at both ends of the middle portion 331, and the middle portions 331 of the two limiting rods 330 overlap.

[0054] In this embodiment, the two limiting rods 330 are respectively the first limiting rod 330 and the second limiting rod 330, which are arranged orthogonally. Each limiting rod 330 includes a middle part 331 and limiting parts 332 respectively disposed at both ends of the middle part 331, that is, the floating structure 300 has four limiting parts 332. When the longitudinal sliding limiter 333 at one end of the first limiting rod 330 is adjusted along the first direction by adjusting the position of the first limiting rod 330 along the first direction by adjusting the transverse adjusting bolt 342, the middle part 331 will be moved along the first direction to adjust the axial position of the second permanent magnet 320.

[0055] Furthermore, the length of the connecting shaft 3331 is greater than the length of the guide groove 3333 along the axial direction of the connecting shaft 3331, so that the connecting shaft 3331 can also move axially within the guide groove 3333. Specifically, when the position of the longitudinal sliding limiter 333 at one end of the first limiting rod 330 along the first direction is adjusted by the transverse adjusting bolt 342, the second limiting rod 330 will be moved along the first direction at the same time. That is, the guide groove 3333 on the second limiting rod 330 will also move along the first direction. At this time, the connecting shaft 3331 can also move axially within the guide groove 3333, so that the second limiting rod 330 can drive the guide groove 3333 to move relative to the connecting shaft 3331 along the first direction, thereby keeping the positions of the two rollers 3332 on the second limiting rod 330 unchanged, that is, ensuring that the two rollers 3332 are always located within the groove 211.

[0056] It should be noted that, in order to facilitate the movement of the connecting shaft 3331 within the guide groove 3333, baffles are respectively provided on both radial sides of the connecting shaft 3331. One end of the elastic element 341 is connected to the inner wall of the guide groove 3333, and the other end is connected to the baffle. One end of the adjusting bolt is connected to the baffle and is used to connect to the connecting shaft 3331 through the baffle.

[0057] For example, the central section 331 includes two annular structures along the direction of gravity. Two limiting rods 330 are connected to the two annular structures one-to-one. The floating structure 300 also includes a connecting spindle 360, which passes through the inner rings of both annular structures. One end of the connecting spindle 360 ​​is connected to a reference prism, and the other end is connected to a gravity mounting base. The thickness of the limiting rods 330 along the direction of gravity is equal to the total thickness of the two annular structures. During installation, the two limiting rods 330 are stacked opposite each other and fixed to the connecting spindle 360.

[0058] For example, the limit rod 330 is made of carbon fiber reinforced composite material, which gives it a smaller mass and better resistance to bending deformation, thus reducing horizontal displacement; or it can be made of materials such as magnesium alloy.

[0059] In some embodiments, a first lateral adjusting bolt is provided on the limiting portion 332 at one end of each limiting rod 330, and a second lateral adjusting bolt is provided at the other end. The diameter of the first lateral adjusting bolt is larger than that of the second lateral adjusting bolt. When the first lateral adjusting bolt is rotated, the first lateral adjusting bolt can quickly adjust the floating structure 300.

[0060] Furthermore, since the first and second lateral adjusting bolts are installed, the center of gravity of the floating structure 300 is easily unbalanced. Therefore, a counterweight screw can be installed on one side of the second lateral adjusting bolt to adjust the balance of the center of gravity of the floating structure 300.

[0061] Combination Figure 2 In some embodiments, each fixed structure 100 is further provided with an annular cavity 130, and a coil is provided in the annular cavity 130. The annular cavity 130 is coaxially arranged with the first embedded groove so as to generate a magnetic field with a highly uniform magnetic induction intensity gradient around the axis, thereby facilitating the uniformity of the magnetic force on the second permanent magnet 320 in space. The uniformity of the magnetic field gradient is the basis for using electromagnets for magnetic force feedback control and long drift compensation.

[0062] Combination Figure 2 In some embodiments, each fixed structure 100 is provided with an axial adjustment member 140 extending along a first direction. The axial adjustment member 140 is located on the side of the first permanent magnet 120 away from the second permanent magnet 320, and the adjustment end of the axial adjustment member 140 abuts against the first permanent magnet 120.

[0063] In this embodiment, the axial adjustment component 140 is an axial adjustment bolt, which is threadedly connected to the fixed structure 100. When the axial adjustment bolt is rotated, it can push the first permanent magnet 120 to move along the direction of gravity. Specifically, the direction of gravity is the direction of gravity, that is, the two fixed structures 100 are located on the upper and lower sides of the floating structure 300, respectively, and the two first permanent magnets 120 are located on the upper and lower sides of the second permanent magnet 320, respectively. The upper fixed structure 100 is provided with a first axial adjustment bolt, which is located above the corresponding first permanent magnet 120. When the first axial adjustment bolt is rotated, the end of the first axial adjustment bolt can abut against the upper first permanent magnet 120 to adjust the position of the upper first permanent magnet 120. Similarly, a second axial adjustment bolt is provided on the lower fixed structure 100. The second axial adjustment bolt is located below the corresponding first permanent magnet 120. When the second axial adjustment bolt is rotated, its end abuts against the lower first permanent magnet 120 to adjust its position. That is, the axial adjustment component 140 can adjust the distance between the two first permanent magnets 120, facilitating the adjustment of the magnetic field gradient.

[0064] In other embodiments, the axial adjustment member 140 may also be a cylinder, a telescopic rod, an electric cylinder, etc.

[0065] To prevent damage to the first permanent magnet 120 from the end of the axial adjusting bolt when rotating it, a shim is provided between each axial adjusting bolt and the first permanent magnet 120.

[0066] In some embodiments, each fixed structure 100 is provided with a plurality of axial adjustment members 140, and the plurality of axial adjustment members 140 can be adjusted individually.

[0067] For example, each fixed structure 100 is provided with four axial adjustment components 140, which are located at four positions on the fixed structure 100. By adjusting the axial adjustment bolts at different positions, the orientation of the first permanent magnet 120 can be changed. By adjusting the orientation of the first permanent magnet 120, the problem of poor uniformity of the magnetic field gradient caused by installation accuracy and magnetization errors can be avoided.

[0068] Combination Figure 3 In some embodiments, one end of the floating structure 300 along the direction of gravity is connected to a counterweight mounting base 400, and a gravity block is provided inside the counterweight mounting base 400.

[0069] In this embodiment, because the magnetization result of the permanent magnet cannot be guaranteed to be accurate, the permanent magnet magnetic field that is highly consistent with the simulation result cannot be obtained; that is, the magnitude of the static magnetic force used to balance gravity is inaccurate. In order to achieve a high-precision balance between gravity and static magnetic force, this application requires that the mass design of the floating structure 300 include a certain redundancy; that is, the floating structure 300 must be lighter than the simulation result of the permanent magnet's magnetic force. When the magnetism of the permanent magnet changes during the initial setup of the system and after long-term use, the mass of the gravity block is adjusted as needed so that the floating body is close to a critical equilibrium state under the condition that the electro-permanent magnet does not apply electromagnetic force, at which point the magnetostatic stiffness is minimal.

[0070] For example, the opening of the second embedding groove faces downward, the inner wall of the second embedding groove is provided with an internal thread, and the top of the counterweight mounting base 400 is provided with an external thread. When the counterweight mounting base 400 is threadedly connected to the inner wall of the second embedding groove, the counterweight mounting base 400 can seal the second permanent magnet 320 in the second embedding groove.

[0071] The counterweight mounting base 400 has mounting holes 410 formed along two mutually perpendicular diameter directions. The inner wall of each mounting hole 410 has a stepped structure. For example, each mounting hole 410 is divided into a first mounting hole 410, a second mounting hole 410, and a third mounting hole 410 connected sequentially from bottom to top. The diameter of the third mounting hole 410 is larger than that of the second mounting hole 410, and the diameter of the second mounting hole 410 is larger than that of the first mounting hole 410. The central axes of the first, second, and third mounting holes 410 coincide along their diameters, resulting in a stepped structure on the inner wall of the entire mounting hole 410. This allows the counterweight to enter from the upper mounting hole 410 to the lower mounting hole 410.

[0072] For example, the second mounting hole 410 has a diameter dimension that is 1.5 times that of the first mounting hole 410, and the third mounting hole 410 has a diameter dimension that is 1.5 times that of the second mounting hole 410.

[0073] Combination Figure 8In some embodiments, the vertical vibration isolation device includes a secondary vibration isolation module 20. The secondary vibration isolation module 20 includes a mounting plate 201, an optical plate 202, and a piezoelectric actuator 203 disposed between the mounting plate 201 and the optical plate 202. A connecting assembly 200 is fixed on the optical plate 202. A laser is mounted on the mounting plate 201. A light-transmitting hole 2021 extending along the direction of gravity is opened on the optical plate 202. A first reflector 204, a second reflector 205, and a detector 207 are mounted on the optical plate 202. The bottom of the floating structure 300 is provided with a connection to the second reflector 205. A third reflector 206 is positioned opposite to the laser; the light emitted by the laser passes through the light-transmitting hole 2021 and is reflected by the first reflector 204 to the second reflector 205, and then reflects multiple times between the second reflector 205 and the third reflector 206 before illuminating the detector 207; the secondary vibration isolation module 20 includes a control unit, which is electrically connected to the detector 207 and the piezoelectric actuator 203 respectively. The control unit is used to adjust the piezoelectric actuator 203 according to the position of the light spot detected by the detector 207, so that the piezoelectric actuator 203 adjusts the position of the optical plate 202.

[0074] In this embodiment, the laser light passes through the light-transmitting aperture 2021 along the direction of gravity, and the light-transmitting aperture 2021 can filter out the relative displacement of the light light in the direction of gravity. The light emitted by the laser passes through the light-transmitting aperture 2021 and is reflected by the first reflector 204 to the second reflector 205. After multiple reflections between the second reflector 205 and the third reflector 206, it illuminates the detector 207. The detector 207 transmits the received light spot information to the controller. The controller is used to adjust the length of different piezoelectric actuators 203 according to the light spot information, thereby reducing the relative displacement between the optical plate 202 and the floating structure 300. At the same time, since the optical plate 202 is fixedly connected to the connecting component 200, and the connecting component 200 is fixedly connected to the fixed structure 100, this is equivalent to further reducing the relative displacement between the fixed structure 100 and the floating structure 300. In this example, there are four light-transmitting apertures 2021.

[0075] Combination Figure 1In some embodiments, the connecting assembly 200 includes a pressure block 230, a column 220, a limiting post 210, and a reinforcing plate 240. The column 220 is an L-shaped column. The bottoms of the L-shaped column 220 and the limiting post 210 are fixed to the optical plate 202. One end of the pressure block 230 along the radial direction of the first permanent magnet 120 is pressed and fixed to the fixed structure 100 located above. The bent section of the L-shaped column 220 is pressed and fixed to the other end of the pressure block 230 along the radial direction of the first permanent magnet 120. The L-shaped columns 220 are arranged in pairs, and the two bent sections of the same pair of L-shaped columns 220 extend toward each other. Two limiting posts 210 are arranged between the same pair of L-shaped columns 220. The end of the limiting part 332 away from the middle part 331 cooperates with the connecting assembly 200 to limit the displacement of the floating structure 300 along the direction of gravity. Each limiting post 210 has a groove 211 extending along the direction of gravity, and the grooves 211 on two limiting posts 210 are aligned with each other between the same pair of L-shaped posts 220, so that the rollers 3332 at both ends of the longitudinal sliding limiter 333 respectively engage with the two grooves 211 and roll in connection. A reinforcing plate 240 is provided between two adjacent pairs of L-shaped posts 220.

[0076] In some embodiments, a water-cooling pipe 500 is wound around the outer wall of the first embedding groove. The water-cooling pipe 500 is used to ensure that the first magnet is in a relatively stable temperature environment and reduce the influence of temperature on the uniformity of the magnetic field.

[0077] An embodiment of this application also provides a gravity acceleration measuring instrument, which includes a reference prism 600 and a vertical vibration isolation device. The reference prism 600 is disposed at one end of the floating structure 300 away from the direction of gravity.

[0078] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0079] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A vertical vibration isolation device, characterized by comprising: The vertical vibration isolation device includes a primary vibration isolation module, which comprises: Two fixed structures are arranged at intervals along the direction of gravity. A first embedding groove is opened on the side of the two fixed structures that are close to each other, and a first permanent magnet is arranged in each of the first embedding grooves. A connecting component connects the two fixed structures such that the projections of the two first embedding slots along the direction of gravity coincide; A floating structure is located between two fixed structures. The floating structure has a middle part and at least two limiting parts. One end of each limiting part is connected to the middle part, and the other end of each limiting part cooperates with the connecting assembly to limit the displacement of the floating structure along the direction of gravity. A second embedding groove is provided on the middle part, and a second permanent magnet is provided in the second embedding groove. The end of the limiting part away from the middle part is rolled or slidably connected to the connecting component along the direction of gravity, so that the limiting part can drive the second permanent magnet to move along the direction of gravity. One of the connecting component and the limiting part is provided with a groove extending along the direction of gravity, and the other is provided with a longitudinal sliding limiter. The longitudinal sliding limiter is matched with the groove along a first direction, which is perpendicular to the direction of gravity.

2. The vertical vibration isolation device according to claim 1, characterized in that, The connecting component has a groove extending along the direction of gravity, and the limiting part is provided with a longitudinal sliding limiter; the longitudinal sliding limiter includes a connecting shaft and rollers respectively disposed at both ends of the connecting shaft, and each roller can roll in the corresponding groove.

3. The vertical vibration isolation device according to claim 2, characterized in that, The limiting part has a guide groove extending in a second direction at one end away from the middle part, and the longitudinal sliding limiter passes through the guide groove. The second direction is perpendicular to both the gravity direction and the first direction. The floating structure is also provided with a lateral adjustment component, which is used to adjust the position of the longitudinal sliding limiter in the guide groove along the first direction.

4. The vertical vibration isolation device according to claim 3, characterized in that, The lateral adjustment assembly includes an elastic element and a lateral adjustment bolt. The elastic element and the lateral adjustment bolt are located at opposite ends of the connecting shaft along the first direction. The end of the elastic element away from the connecting shaft abuts against the inner wall of the guide groove, and the lateral adjustment bolt is threadedly connected to the side wall of the guide groove.

5. The vertical vibration isolation device according to claim 1, characterized in that, The floating structure includes two mutually perpendicular limiting rods. Each limiting rod includes a middle section and limiting portions respectively disposed at both ends of the middle section. The middle sections of the two limiting rods overlap.

6. The vertical vibration isolation device according to claim 1, characterized in that, Each of the fixed structures is provided with an axial adjustment member extending along a first direction. The axial adjustment member is located on the side of the first permanent magnet away from the second permanent magnet, and the adjustment end of the axial adjustment member abuts against the first permanent magnet.

7. The vertical vibration isolation device according to claim 6, characterized in that, Each of the fixed structures is provided with multiple axial adjustment components, and the multiple axial adjustment components can be adjusted individually.

8. The vertical vibration isolation device according to claim 1, characterized in that, The floating structure is connected to a counterweight mounting base at one end along the direction of gravity, and a gravity block is installed inside the counterweight mounting base.

9. The vertical vibration isolation device according to claim 1, characterized in that, The vertical vibration isolation device includes a secondary vibration isolation module, which includes a mounting plate, an optical plate, and a piezoelectric actuator disposed between the mounting plate and the optical plate. The connecting component is disposed on the optical plate. A laser is mounted on the mounting plate. A light-transmitting hole extending along the direction of gravity is opened on the optical plate. A first reflector, a second reflector, and a detector are mounted on the optical plate. A third reflector is disposed at the bottom of the floating structure opposite to the second reflector. The light emitted by the laser passes through the light-transmitting hole and is reflected by the first reflector to the second reflector. After multiple reflections between the second and third reflectors, the light then illuminates the detector. The secondary vibration isolation module includes a control unit, which is electrically connected to the detector and the piezoelectric actuator respectively. The control unit is used to adjust the piezoelectric actuator according to the position of the light spot detected by the detector, so that the piezoelectric actuator adjusts the position of the optical plate.

10. A gravity acceleration measuring instrument, characterized in that, The gravity acceleration measuring instrument includes a reference prism and a vertical vibration isolation device as described in any one of claims 1-9, wherein the reference prism is disposed at one end of the floating structure opposite to the direction of gravity.

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