A three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load

Abstract

This invention belongs to the field of structural vibration reduction and isolation technology, specifically relating to a three-dimensional multi-stage stiffness-limiting vibration isolation device with adjustable load. The device includes a vertical multi-stage stiffness-limiting isolator and two horizontal multi-stage stiffness isolators. The vertical multi-stage stiffness-limiting isolator includes a bearing plate and upper and lower limiting plates, a vertical positive stiffness mechanism between the bearing plate and the upper limiting plate, and a vertical negative stiffness mechanism between the upper and lower limiting plates. The upper horizontal multi-stage stiffness isolator includes a base plate parallel to the connecting plate, and a horizontal positive stiffness mechanism and a horizontal negative stiffness mechanism between the base plate and the connecting plate. This invention is based on the parallel connection of the vertical and horizontal multi-stage stiffness-limiting isolators, enabling them to provide positive stiffness in the initial stage. After reaching a preset displacement, the parallel positive and negative stiffness mechanisms provide quasi-zero stiffness to meet the needs of practical engineering.

Description

Technical Field

[0001] This invention belongs to the field of structural vibration reduction and isolation technology, specifically relating to a three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load. Background Technology

[0002] Passive vibration isolation technology isolates ground vibrations from the superstructure by setting up isolation layers and using vibration isolators, effectively protecting the isolated object from damage. The vibration isolation performance of linear isolators can be improved by reducing their linear stiffness. However, low stiffness leads to large static displacements in linear isolators. To overcome this drawback, nonlinear isolators with high static stiffness and low dynamic stiffness have been proposed. Higher static stiffness means smaller deflection and greater load-bearing capacity, while lower dynamic stiffness means a wider isolation frequency range. The stiffness characteristics of nonlinear isolators can be achieved by combining positive and negative stiffness, resulting in near-zero stiffness at the operating point, which is referred to as quasi-zero stiffness characteristics in practical engineering.

[0003] Existing quasi-zero stiffness vibration isolation devices are mostly used for vertical or horizontal vibration isolation, lacking research on three-dimensional vibration isolation. Furthermore, when interference loads appear in the vibration isolation structure, there will be significant disturbances, affecting the stability of the system. Summary of the Invention

[0004] This invention provides a three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load. It is based on the parallel connection of a vertical multi-level stiffness limiting vibration isolator and a horizontal multi-level stiffness vibration isolator, so that the two provide positive stiffness in the initial stage and provide quasi-zero stiffness through the parallel connection of positive and negative stiffness mechanisms after reaching the preset displacement, so as to meet the needs of practical engineering.

[0005] The technical solution adopted by this invention to solve its technical problem is: a three-dimensional multi-stage stiffness limiting vibration isolation device with adjustable load, comprising a vertical multi-stage stiffness limiting vibration isolator and two horizontal multi-stage stiffness vibration isolators, wherein:

[0006] The vertical multi-stage stiffness limiting vibration isolator includes a bearing plate, an upper limit plate, a lower limit plate, a vertical positive stiffness mechanism, a vertical negative stiffness mechanism, an adjusting support part, and a connecting rod;

[0007] The load-bearing plate, the upper limit plate, and the lower limit plate are arranged sequentially at intervals.

[0008] A vertical positive stiffness mechanism is positioned between the bearing plate and the upper limit plate. This mechanism comprises four vertical steel springs, which are the elastic elements of the mechanism. All four springs have the same linear stiffness coefficient. ;

[0009] A vertical negative stiffness mechanism is positioned between the upper limit plate and the lower limit plate. The mechanism includes eight sets of inclined elastic components, each containing a first pre-compressed inclined steel spring. These first pre-compressed inclined steel springs are the elastic elements of the vertical negative stiffness mechanism, and all eight springs have the same linear stiffness coefficient. ;

[0010] The adjustable support is positioned between the upper limit plate and the lower limit plate;

[0011] One end of the connecting rod is detachably connected to the bearing plate, and the other end of the connecting rod passes through the upper limit plate to connect the vertical positive stiffness mechanism and the vertical negative stiffness mechanism. A first central connecting block is provided at the end of the connecting rod away from the bearing plate, and the first central connecting block can move on the connecting rod.

[0012] The horizontal multi-stage stiffness vibration isolator includes a connecting plate, a base plate, a horizontal negative stiffness mechanism, and a horizontal positive stiffness mechanism;

[0013] The connecting plate and the base plate are distributed vertically. Two guide rails are set on the bottom surface of the connecting plate, and a transmission block is set in the middle of the connecting plate. The transmission block can move linearly along the bottom surface of the connecting plate.

[0014] Four limiting sliders are set at the four corners of the top surface of the base plate, and two limiting sliders located below the same guide rail are slidably connected to this guide rail;

[0015] A horizontal negative stiffness mechanism and a horizontal positive stiffness mechanism are set between the base plate and the connecting plate. The horizontal negative stiffness mechanism is set between the four limit sliders, and the horizontal positive stiffness mechanism is set on the side of the four limit sliders away from the horizontal negative stiffness mechanism.

[0016] The horizontal negative stiffness mechanism includes a second central connecting block and four sets of second pre-compressed inclined steel springs. The second central connecting block is fitted onto the transmission block. The four sets of second pre-compressed inclined steel springs are horizontally and symmetrically arranged around the second central connecting block. The linear stiffness coefficients of the four sets of second pre-compressed inclined steel springs are the same.

[0017] The horizontal stiffness mechanism includes two baffles, four sets of horizontal steel springs, and two second slide rods. The baffles are set on the base plate and are located on the side of the guide rail facing the external environment. Each baffle has a set of horizontal steel springs on both sides. The four sets of horizontal steel springs have the same linear stiffness coefficient. The second slide rods are set parallel to the side of the guide rail facing the external environment, and each second slide rod passes through two sets of horizontal steel springs and one baffle.

[0018] Two horizontal multi-stage stiffness vibration isolators are arranged in a cross shape, one above the other.

[0019] The vertical multi-stage stiffness limiting vibration isolator adjusts the stiffness ratio between the elastic element of the vertical negative stiffness mechanism and the elastic element of the vertical positive stiffness mechanism. The actual pre-compression coefficient of the elastic element in a vertical negative stiffness mechanism Vertical compression stroke of the elastic element in a vertical negative stiffness mechanism This achieves the vertical quasi-zero stiffness characteristic at the static equilibrium position, thus realizing the nonlinear vibration isolation effect of high static stiffness and low dynamic stiffness.

[0020] To achieve the vertical quasi-zero stiffness characteristics of the three-dimensional multi-level stiffness limiting vibration isolation device, , , The three parameters satisfy formula (1), which is as follows:

[0021] (1)

[0022] In formula (1), ;

[0023] The horizontal multi-stage stiffness isolator located below, with the direction in which its transmission block can move taken as the X-axis, has its linear stiffness coefficient denoted as for each second pre-compressed inclined steel spring in the horizontal multi-stage stiffness isolator located below. The linear stiffness coefficient of each horizontal steel spring is denoted as . ;

[0024] The horizontal multi-stage stiffness isolator located below adjusts the stiffness ratio between the second pre-compressed inclined steel spring and the horizontal steel spring. The actual pre-compression coefficient of the second pre-compression inclined steel spring The compression stroke of the second pre-compressed inclined steel spring in the horizontal multi-stage stiffness isolator located below. The relationship between the three parameters enables the horizontal multi-stage stiffness isolator located below to acquire different horizontal quasi-zero stiffness mechanical properties, thereby achieving a multi-functional vibration isolation effect.

[0025] The horizontal multi-stage stiffness isolator located at the top, with its transmission block moving in the Y direction, has its linear stiffness coefficient of each second pre-compressed inclined steel spring denoted as [missing information]. The linear stiffness coefficient of each horizontal steel spring is denoted as . ;

[0026] The horizontal multi-stage stiffness isolator located above adjusts the stiffness ratio of the second pre-compressed inclined steel spring to the horizontal steel spring. The actual pre-compression coefficient of the second pre-compression inclined steel spring The compression stroke of the second pre-compressed inclined steel spring in the horizontal multi-stage stiffness isolator located above. The relationship between the three parameters enables the horizontal multi-stage stiffness vibration isolator located above to acquire different horizontal quasi-zero stiffness mechanical properties, thereby achieving a multi-functional vibration isolation effect.

[0027] To achieve the horizontal quasi-zero stiffness mechanical properties of the three-dimensional multi-level stiffness limiting vibration isolation device, , , The three parameters satisfy formula (2). , , The three parameters satisfy formula (3). Formulas (2) and (3) are as follows:

[0028] (2)

[0029] (3)

[0030] In formula (2), ;In formula (3), .

[0031] As a further preferred embodiment of the present invention, the vertical positive stiffness mechanism further includes four first sliding rods, which are disposed between the bearing plate and the upper limit plate; a vertical steel spring is sleeved on the outside of the first sliding rods, with one end of the vertical steel spring connected to the bearing plate and the other end passing through the upper limit plate.

[0032] As a further preferred embodiment of the present invention, the adjusting support includes four supporting cylinders and eight circular hole sliders. The four supporting cylinders are supported between the upper limit plate and the lower limit plate. Each supporting cylinder is equipped with two circular hole sliders, which can slide on the supporting cylinder.

[0033] As a further preferred embodiment of the present invention, it also includes eight first sliders, each of which is mounted on a circular hole slider, and all eight first sliders face the middle of the upper limit plate and the lower limit plate; at the same time, the first sliders can slide on the side wall connected to the circular hole slider.

[0034] As a further preferred embodiment of the present invention, the elastic component further includes a first piston rod and a first piston sleeve. One end of the first piston rod is connected to the first slider, and the other end is located inside the first piston sleeve. The end of the first piston sleeve facing away from the first piston rod is connected to the first central connecting block. A first pre-compressed inclined steel spring is sleeved outside the first piston rod and the first piston sleeve.

[0035] As a further preferred embodiment of the invention, it also includes four second sliders, two of which are slidably connected to each guide rail, and each second slider is connected to a limiting slider, while each second slider is connected to a set of second pre-compressed inclined steel springs.

[0036] As a further preferred embodiment of the present invention, the horizontal negative stiffness mechanism further includes a second piston rod and a second piston sleeve. One end of the second piston rod is connected to the second central connecting block, and the other end is located inside the second piston sleeve. The end of the second piston sleeve opposite to the second piston rod is connected to a second slider. A second pre-compressed inclined steel spring is sleeved outside the second piston sleeve.

[0037] As a further preferred embodiment of the present invention, it also includes four support plates, which are disposed on the side of the limiting slider away from the horizontal negative stiffness mechanism, and the two ends of the second slider are respectively connected to a support plate.

[0038] As a further preferred embodiment of the present invention, a waist hole is provided in the middle of the second central connecting block, and the transmission block is located in the waist hole, so that the transmission block can move linearly within the waist hole of the second central connecting block.

[0039] As a further preferred embodiment of the present invention, in formula (1), the actual pre-compression coefficient of the elastic element of the vertical negative stiffness mechanism is... Vertical compression stroke of the elastic element in a vertical negative stiffness mechanism The calculation methods are as follows: Formula (1-1) and Formula (1-2):

[0040] (1-1)

[0041] (1-2)

[0042] In formulas (1-1) and (1-2), This is a set value, referring to the pre-compression coefficient of the elastic element in the vertical negative stiffness mechanism; This is a constant value, referring to the distance between the end of the elastic element of the vertical negative stiffness mechanism near the lower limit plate and the connecting rod along the length of the lower limit plate. This is a constant value, referring to the distance between the end of the elastic element of the vertical negative stiffness mechanism near the lower limit plate and the connecting rod in the width direction of the lower limit plate; This refers to the vertical distance in the vertical direction of the elastic element of the vertical negative stiffness mechanism;

[0043] In formula (2), the actual pre-compression coefficient of the second pre-compression inclined steel spring in the horizontal multi-stage stiffness isolator located below is... The compression stroke of the second pre-compressed inclined steel spring in the horizontal multi-stage stiffness isolator located below. The calculation methods are as follows: Formula (2-1) and Formula (2-2):

[0044] (2-1)

[0045] (2-2)

[0046] In formulas (2-1) and (2-2), The set value refers to the pre-compression coefficient of the second pre-compression inclined steel spring in the horizontal multi-stage stiffness isolator located below; This is a constant value, referring to the distance between the two ends of the second pre-compressed inclined steel spring in the X-direction of the horizontal multi-stage stiffness isolator located below; The distance between the two ends of the second pre-compressed inclined steel spring in the X-direction of the horizontal multi-stage stiffness isolator located below;

[0047] In formula (3), the actual pre-compression coefficient of the second pre-compression inclined steel spring in the upper horizontal multi-stage stiffness isolator is... The compression stroke of the second pre-compressed inclined steel spring in the horizontal multi-stage stiffness isolator located above. The calculation methods are as follows: Formula (3-1) and Formula (3-2):

[0048] (3-1)

[0049] (3-2)

[0050] In formulas (3-1) and (3-2), The set value refers to the pre-compression coefficient of the second pre-compression inclined steel spring in the horizontal multi-stage stiffness isolator located above; This is a constant value, referring to the distance between the two ends of the second pre-compressed inclined steel spring in the Y direction of the horizontal multi-stage stiffness isolator located above. The distance between the two ends of the second pre-compressed inclined steel spring in the Y direction in the horizontal multi-stage stiffness isolator located above.

[0051] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

[0052] 1. This invention can achieve a nonlinear vibration isolation effect with high static stiffness and low dynamic stiffness by adjusting the pre-compression coefficient of the first pre-compression inclined steel spring of the vertical negative stiffness mechanism and the second pre-compression inclined steel spring of the horizontal negative stiffness mechanism, the stiffness ratio of the first pre-compression inclined steel spring of the vertical negative stiffness mechanism and the second pre-compression inclined steel spring of the horizontal negative stiffness mechanism, and the vertical compression stroke of the first pre-compression inclined steel spring of the vertical negative stiffness mechanism and the second pre-compression inclined steel spring of the horizontal negative stiffness mechanism.

[0053] 2. The spacing between the upper and lower limiting plates of this invention restricts the compression displacement stroke of the vertical negative stiffness mechanism, and the spacing between the two limiting sliders on the guide rail restricts the compression displacement stroke of the horizontal negative stiffness mechanism, so that this vibration isolation device does not fail due to excessive displacement of the elastic element, effectively improving the stability of the vibration isolation system.

[0054] 3. The present invention can inject liquid viscous damping into the first piston rod and the first piston sleeve, and the second piston rod and the first piston sleeve, and use the turbulence of the damping liquid to absorb energy. The additional damping works in conjunction with the first pre-compressed inclined steel spring of the vertical negative stiffness mechanism and the second pre-compressed inclined steel spring of the horizontal negative stiffness mechanism to solve the problem of horizontal and vertical displacement amplification caused by a single quasi-zero stiffness, so that the displacement can be effectively controlled.

[0055] 4. This invention can activate the vertical positive stiffness mechanism by adjusting the distance between the nut and the first central connecting block, thereby achieving vertical multi-level stiffness characteristics. At the same time, the distance between the transmission block and the second central connecting block can be adjusted by adding a screw bolt, so that this vibration isolation device can achieve horizontal multi-level stiffness mechanical properties to meet the needs of different practical engineering projects. Attached Figure Description

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0057] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0058] Figure 2 This is a schematic diagram of the vertical negative stiffness mechanism damper and the connected circular hole slider of the present invention;

[0059] Figure 3 This is a schematic diagram of the structure of the horizontal multi-stage stiffness limiting vibration isolator of the present invention;

[0060] Figure 4 This is the present invention. Figure 3 Enlarged detail image of point A in the middle;

[0061] Figure 5 This is an exploded view of the horizontal multi-stage stiffness limiting vibration isolator of the present invention;

[0062] Figure 6 This is a schematic diagram of the parameter markings in formulas (1), (1-1), and (1-2) of this invention;

[0063] Figure 7 This is a schematic diagram of the parameter markings in formulas (2), (2-1), (2-2), (3), (3-1), and (3-2) of this invention.

[0064] In the diagram: 1-Bearing plate, 2-Vertical steel spring, 3-First slide rod, 4-Upper limit plate, 5-Round hole slider, 6-Screw bolt, 7-First slider, 8-First bolt, 9-Support cylinder, 10-First piston rod, 11-First pre-compressed inclined steel spring, 12-First piston sleeve, 13-First central connecting block, 14-Nut, 15-Connecting rod, 16-Screw, 17-Lower limit plate, 18-Baffle, 19-Connecting plate, 20-Support plate, 21-Horizontal steel spring, 22-Second slide rod, 23-Guide rail, 24-Limit slider, 25-Second slider, 26-Base plate, 27-Second pre-compressed inclined steel spring, 28-Second central connecting block, 29-Transmission block, 30-Round head bolt, 31-Second bolt, 32-Second piston sleeve, 33-Second piston rod. Detailed Implementation

[0065] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0066] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0067] Example 1

[0068] This embodiment provides a preferred implementation scheme, a three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load, such as... Figures 1 to 7 As shown, this vibration isolation device includes a vertical multi-stage stiffness limiting vibration isolator and two horizontal multi-stage stiffness vibration isolators. The two horizontal multi-stage stiffness vibration isolators are arranged in a cross shape vertically.

[0069] The aforementioned vertical multi-stage stiffness limiting vibration isolator includes a bearing plate 1, an upper limit plate 4, a lower limit plate 17, a vertical positive stiffness mechanism, an adjusting support, a vertical negative stiffness mechanism, and a connecting rod 15. The bearing plate 1, upper limit plate 4, and lower limit plate 17 are arranged sequentially at intervals. The vertical positive stiffness mechanism is located between the bearing plate 1 and the upper limit plate 4. Both the vertical negative stiffness mechanism and the adjusting support are located between the upper limit plate 4 and the lower limit plate 17. The vertical negative stiffness mechanism includes eight sets of inclined elastic components. One end of the connecting rod 15 is detachably connected to the bearing plate 1, and the other end of the connecting rod 15 passes through the upper limit plate 4, connecting the vertical positive stiffness mechanism and the vertical negative stiffness mechanism. A first central connecting block 13 is provided at the end of the connecting rod 15 facing away from the bearing plate 1, and the first central connecting block 13 can move on the connecting rod 15. Figure 1 and Figure 6 (The connecting rod 15 between the middle bearing plate 1 and the upper limit plate 4 is not shown)

[0070] The aforementioned vertical positive stiffness mechanism includes four first slide rods 3 and four vertical steel springs 2. The four first slide rods 3 are disposed between the bearing plate 1 and the upper limit plate 4. One end of each first slide rod 3 is connected to the bearing plate 1 (preferably a detachable connection), and the other end passes through the upper limit plate 4. The first slide rods 3 maintain the stability of the vertical steel springs 2 during compression in the vertical positive stiffness mechanism and can adjust the compression amount of the vertical steel springs 2 in the vertical positive stiffness mechanism. Preferably, the four first slide rods 3 are symmetrically distributed between the bearing plate 1 and the upper limit plate 4, with the center of the space between the bearing plate 1 and the upper limit plate 4 as the center, to prevent the bearing plate 1 from twisting or overturning due to uneven compression after the vibration isolation object is placed. The four vertical steel springs 2 are the elastic elements of the vertical positive stiffness mechanism, and the linear stiffness coefficients of the four vertical steel springs are the same. The vertical steel spring 2 is sleeved outside the first slide rod 3, with one end of the vertical steel spring 2 in contact with the bearing plate 1 and the other end in contact with the upper limit plate 4.

[0071] Preferably, the inner diameter of the vertical steel spring 2 is 1mm to 2mm larger than the inner diameter of the first slide rod 3. A diameter greater than 2mm will cause instability during compression of the vertical steel spring 2, while a diameter less than 1mm will cause unnecessary friction during compression. The upper and lower ends of the vertical steel spring 2 need to be smoothly ground to prevent eccentric forces from occurring after contact with the bearing plate 1 and the upper limit plate 4. A nylon sleeve or linear bearing can be added to the part of the first slide rod 3 that passes through the upper limit plate 4 to reduce friction during vertical compression.

[0072] The aforementioned adjusting support includes four supporting cylinders 9 and eight circular hole sliders 5. The four supporting cylinders 9 are supported between the upper limit plate 4 and the lower limit plate 17, limiting the distance between the upper limit plate 4 and the lower limit plate 17. Each supporting cylinder 9 is equipped with two circular hole sliders 5, which can slide on the supporting cylinder 9. The distance between the upper limit plate 4 and the lower limit plate 17 limits the compression displacement stroke of the vertical negative stiffness mechanism. By adjusting the position of the two circular hole sliders 5 on the supporting cylinders 9, the compression amount of the elastic element of the vertical negative stiffness mechanism and the vertical compression stroke of the elastic element of the vertical negative stiffness mechanism are limited.

[0073] This embodiment also includes eight first sliders 7, each mounted on a circular hole slider 5, with all eight first sliders 7 facing the middle of the upper limit plate 4 and the lower limit plate 17; simultaneously, the first sliders 7 can slide on the side wall connected to the circular hole slider 5. Specifically, the position of the first slider 7 on the circular hole slider 5 is limited by screws 16. When the first slider 7 is mounted on the circular hole slider 5, the first slider 7 can slide vertically on the circular hole slider 5. Adjusting the position of the first slider 7 on the circular hole slider 5 allows for secondary adjustment of the compression amount of the elastic component of the vertical negative stiffness mechanism and the vertical compression stroke of the elastic component of the vertical negative stiffness mechanism.

[0074] The above eight sets of elastic components are all connected at one end to the first central connecting block 13, and at the other end to a circular hole slider 5 via a first slider 7. Each elastic component includes a first pre-compression inclined steel spring 11, a first piston rod 10, and a second piston sleeve 32. The first pre-compression inclined steel spring 11 is the elastic element of the vertical negative stiffness mechanism, and all eight first pre-compression inclined steel springs 11 have the same linear stiffness coefficient. One end of the first piston rod 10 is connected to the first slider 7, and the other end is located inside the first piston sleeve 12. The end of the first piston sleeve 12 opposite to the first piston rod 10 is hinged to the first central connecting block 13. Preferably, the first piston rod 10 is hinged to the first slider 7 by the first bolt 8; a viscous damping fluid is provided in the space between the first piston rod 10 and the first piston sleeve 12, and the turbulence of the damping fluid is used to absorb energy. The additional damping, together with the first pre-compressed inclined steel spring 11, solves the problem of vertical displacement amplification caused by a single quasi-zero stiffness, thus effectively controlling the displacement.

[0075] The eight sets of inclined elastic components are symmetrically arranged vertically and have the same vertical compression stroke. The first pre-compression inclined steel spring 11 uses spring elements with the same stiffness characteristics and compression coefficient, which simplifies the device parameters and facilitates the achievement of quasi-zero stiffness characteristics. The design of the quasi-zero stiffness characteristics of the vertical multi-stage stiffness limiting vibration isolator mainly depends on three parameters: the stiffness ratio of the vertical steel spring 2 of the vertical positive stiffness mechanism to the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism, the pre-compression coefficient of the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism, and the vertical compression stroke of the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism. By adjusting the specific relationship between these three parameters, different quasi-zero stiffness mechanical properties can be obtained, achieving a multi-functional vibration isolation effect.

[0076] The circular hole slider 5 is equipped with a lead screw 6, which can be used to fix or slide the circular hole slider 5 onto the supporting cylinder 9. When the circular hole slider 5 slides on the supporting cylinder 9, the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism will only be in two states: the pre-compression is released to 0 and the pre-compression continues to increase. The first pre-compression inclined steel spring 11 will not change from compression to tension. When the circular hole slider 5 is fixed on the supporting cylinder 9, the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism will be in two states: the pre-compression continues to increase and the pre-compression is released to 0 and then continues to be stretched. Different motion modes can also enable the vertical multi-stage stiffness limiting vibration isolator to obtain different mechanical properties for application in different engineering practices.

[0077] One end of the connecting rod 15 is detachably connected to the bearing plate 1, and the other end is provided with a threaded section. The first central connecting block 13 is installed on the threaded section. This embodiment also includes two nuts 14, which are located in the threaded section of the connecting rod 15 and distributed on both sides of the first central connecting block 13. The position of the first central connecting block 13 on the connecting rod 15 is adjusted by the two nuts 14. One end of the connecting rod 15 is threaded to the bearing plate 1 for easy disassembly and replacement of the elastic element of the vertical positive and negative stiffness mechanism. The nuts 14 can be adjusted according to the different masses of the vibration isolation objects placed on the bearing plate 1. After adjustment, they contact the upper and lower surfaces of the first central connecting block 13, so that the vertical positive and negative stiffness mechanisms are connected in parallel, realizing the adjustable load characteristics of the vertical multi-stage stiffness limiting vibration isolator for application in different vibration isolation scenarios.

[0078] The aforementioned horizontal multi-stage stiffness vibration isolator includes a connecting plate 19, a base plate 26, a horizontal negative stiffness mechanism, and a horizontal positive stiffness mechanism. The connecting plate 19 and the base plate 26 are vertically distributed. Two oppositely distributed guide rails 23 are provided on the bottom surface of the connecting plate 19, and a transmission block 29 is provided in the middle of the connecting plate 19, capable of linear movement along the bottom surface of the connecting plate 19. Four limiting sliders 24 are provided at the four corners of the top surface of the base plate 26, with two limiting sliders 24 located below the same guide rail 23 slidably connected to this guide rail 23. Preferably, the distance between the two limiting sliders 24 on the guide rail 23 is adjusted by regulating the installation position of the limiting sliders 24 on the base plate 26; specifically, the installation and installation position of the limiting sliders 24 and the base plate 26 can be adjusted by providing positioning bolts and several mounting holes. A horizontal negative stiffness mechanism and a horizontal positive stiffness mechanism are provided between the base plate 26 and the bearing plate 1. The horizontal negative stiffness mechanism is located between the four limiting sliders 24, and the horizontal positive stiffness mechanism is located on the side of the four limiting sliders 24 away from the horizontal negative stiffness mechanism.

[0079] Two sets of horizontally multi-stage stiffness isolators are arranged vertically. The connecting plate 19 of the upper horizontally multi-stage stiffness isolator contacts the lower limiting plate 17, and the base plate 26 contacts the connecting plate 19 of the lower horizontally multi-stage stiffness isolator. Preferably, the connecting plate 19 has a C-shaped cross-section, and the lower limiting plate 17 and the base plate 26 have the same structure, with both the lower limiting plate 17 and the base plate 26 being inserted into the connecting plate 19.

[0080] The aforementioned horizontal negative stiffness mechanism includes a second central connecting block 28 and four sets of second pre-compression inclined steel springs 27. The second central connecting block 28 is mounted on the transmission block 29, and the four sets of second pre-compression inclined steel springs 27 are horizontally symmetrically arranged around the second central connecting block 28. The four sets of second pre-compression inclined steel springs 27 have the same linear stiffness and the same compression stroke.

[0081] The aforementioned horizontal positive stiffness mechanism includes two baffles 18, four sets of horizontal steel springs 21, and two second slide rods 22. The baffles 18 are mounted on the base plate 26, located on the side of the guide rail 23 facing the external environment. Each baffle 18 has a set of horizontal steel springs 21 on both sides. The second slide rods 22 are parallel to each other on the side of the guide rail 23 facing the external environment, and each second slide rod 22 passes through two sets of horizontal steel springs 21 and one baffle 18. This embodiment also includes four support plates 20, which are located on the side of the limiting slider 24 away from the horizontal negative stiffness mechanism, and the two ends of each second slide rod 22 are connected to one support plate 20.

[0082] Specifically, the four sets of horizontal steel springs 21 all use the same stiffness coefficient and are symmetrically arranged on both sides of the guide rail 23 and the limiting slider 24 to prevent uneven compression movement of the bearing plate 1 after the vibration isolation object is placed on it, while simplifying the design parameters. The inner diameter of the horizontal steel spring 21 is 1mm to 2mm larger than the inner diameter of the second slide rod 22. A diameter greater than 2mm will cause instability of the horizontal steel spring 21 during compression, while a diameter less than 1mm will cause unnecessary friction during compression. The left and right ends of the horizontal steel spring 21 should be ground smooth to prevent eccentric force from being generated after contacting the baffle 18 and the support plate 20. In addition, a nylon sleeve or linear bearing can be added to the part of the second slide rod 22 that passes through the baffle 18 to reduce the friction during horizontal compression movement. The second slide rod 22 can be fixed to the support plates 20 at both ends by the second bolt 31 for easy assembly and disassembly, which helps to maintain the stability of the horizontal steel spring 21 of the positive stiffness mechanism during compression.

[0083] This implementation also includes four second sliders 25, with two second sliders 25 slidably connected on each guide rail 23, and each second slider 25 is connected to a limiting slider 24. At the same time, each second slider 25 is connected to a set of second pre-compressed inclined steel springs 27.

[0084] The aforementioned horizontal negative stiffness mechanism further includes a second piston rod 33 and a second piston sleeve 32. One end of the second piston rod 33 is connected to the second central connecting block 28, and the other end is located inside the second piston sleeve 32. The end of the second piston sleeve 32 facing away from the second piston rod 33 is connected to a second slider 25. A second pre-compressed inclined steel spring 27 is sleeved on the outside of the second piston sleeve 32. Preferably, the second piston sleeve 32 is connected to the second slider 25 by a round-head bolt 30. A viscous damping fluid is provided in the space between the second piston rod 33 and the second piston sleeve 32, and the turbulence of the damping fluid is used to absorb energy. The additional damping and the second pre-compressed inclined steel spring 27 work together to solve the problem of vertical displacement amplification caused by a single quasi-zero stiffness, so that the displacement is effectively controlled.

[0085] A waist hole is formed in the middle of the second central connecting block 28, and the transmission block 29 is located within the waist hole. The transmission block 29 can move linearly within the waist hole of the second central connecting block 28. By adjusting the initial position of the transmission block 29 within the waist hole of the second central connecting block 28, the horizontal multi-stage stiffness isolator can obtain different multi-stage stiffness characteristics. Preferably, an additional lead screw is used to adjust the initial position of the transmission block 29 within the waist hole of the second central connecting block 28.

[0086] After the vibration isolation device is installed, under the action of three-dimensional ground motion or three-dimensional vibration of the isolated object, the vertical multi-stage stiffness limiting vibration isolator and the horizontal multi-stage stiffness limiting vibration isolator simultaneously generate vertical and horizontal compressive motion through the connection plate 19. The vertical and horizontal positive stiffness mechanisms first work independently to provide positive stiffness in the designed initial displacement stage. After reaching the preset displacement, the vertical and horizontal negative stiffness mechanisms and positive stiffness mechanisms simultaneously generate vertical and horizontal compressive motion through the connection of the transmission mechanism to provide quasi-zero stiffness, so that the system as a whole exhibits three-dimensional multi-stage stiffness characteristics. By adjusting the distance between the nut 14 and the first central connecting block 13, and the spacing between the transmission block 29 and the second central connecting block 28, different three-dimensional multi-stage stiffness mechanical properties can be obtained to meet the needs of different practical engineering projects.

[0087] The aforementioned vertical multi-stage stiffness limiting vibration isolator adjusts the stiffness ratio between the first pre-compressed inclined steel spring 11 in the vertical negative stiffness mechanism and the vertical steel spring 2 in the vertical positive stiffness mechanism. The actual pre-compression coefficient of the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism The vertical compression stroke of the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism This achieves the vertical quasi-zero stiffness characteristic at the static equilibrium position, thus realizing the nonlinear vibration isolation effect of high static stiffness and low dynamic stiffness.

[0088] Specifically, to achieve the vertical quasi-zero stiffness characteristics of the three-dimensional multi-level stiffness limiting vibration isolation device, , , The three parameters satisfy formula (1), which is as follows:

[0089] (1)

[0090] In formula (1), The actual pre-compression coefficient of the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism. The vertical compression stroke of the first pre-compressed inclined steel spring 11 in the vertical negative stiffness mechanism The calculation methods are as follows: Formula (1-1) and Formula (1-2):

[0091] (1-1)

[0092] (1-2)

[0093] In formulas (1-1) and (1-2), The set value refers to the pre-compression coefficient of the first pre-compression inclined steel spring 11 of the vertical negative stiffness mechanism; This is a fixed value, referring to the distance between the end of the first pre-compressed inclined steel spring 11 of the vertical negative stiffness mechanism and the connecting rod 15 in the length direction of the lower limit plate 17. This is a fixed value, referring to the distance between the end of the first pre-compressed inclined steel spring 11 of the vertical negative stiffness mechanism and the connecting rod 15 in the width direction of the lower limit plate 17. The vertical distance of the first pre-compressed inclined steel spring 11 of the vertical negative stiffness mechanism in the vertical direction.

[0094] Known This setting is achieved by adjusting the stroke of the circular hole slider 5 on the supporting cylinder 9 and / or the position of the first central connecting block 13 on the connecting rod 15. Changes have occurred because , As a constant, it can be known that the straight-line distance between the end of the first pre-compressed inclined steel spring 11 connected to the circular hole slider 5 and the axis of the connecting rod 15 is... ,according to and The compression length of the first pre-compressed inclined steel spring 11 is obtained. The vertical compression stroke of the first pre-compressed inclined steel spring 11 in the vertical negative stiffness mechanism is obtained according to formula (1-2). .

[0095] During the adjustment process, the parameters that are known in advance are: , , , , ,according to , achievable , ; will be obtained Substituting into formula (1), we obtain the required result. Then adjust the stroke of the circular hole slider 5 on the supporting cylinder 9 and / or the position of the first central connecting block 13 on the connecting rod 15, and adjust accordingly. infinitely close Then, by adjusting the position of the first slider 7 on the circular hole slider 5, The preferred assembly state of the vertical multi-stage stiffness limiting vibration isolator under the current working conditions is obtained.

[0096] The horizontal multi-stage stiffness isolator located below, with its transmission block moving in the X direction, has its linear stiffness coefficient denoted as [X]. The linear stiffness coefficient of each horizontal steel spring is denoted as . The horizontal multi-stage stiffness isolator located below adjusts the stiffness ratio between the second pre-compressed inclined steel spring 27 and the horizontal steel spring. The actual pre-compression coefficient of the second pre-compression inclined steel spring 27 The compression stroke of the second pre-compressed inclined steel spring 27 in the horizontal multi-stage stiffness isolator located below. The relationship between the three parameters allows the horizontal multi-stage stiffness isolator located below to acquire different horizontal quasi-zero stiffness mechanical properties, thus achieving a multi-functional vibration isolation effect.

[0097] Specifically, to achieve the quasi-zero stiffness mechanical properties of the horizontally multi-stage stiffness isolator located below, , , The three parameters satisfy formula (2), which is as follows:

[0098] (2)

[0099] In formula (2), The actual pre-compression coefficient of the second pre-compression inclined steel spring 27 in the horizontal multi-stage stiffness isolator located below. The compression stroke of the second pre-compressed inclined steel spring 27 in the horizontal multi-stage stiffness isolator located below. The calculation methods are as follows: Formula (2-1) and Formula (2-2):

[0100] (2-1)

[0101] (2-2)

[0102] In formulas (2-1) and (2-2), The set value refers to the pre-compression coefficient of the second pre-compression inclined steel spring 27 in the horizontal multi-stage stiffness isolator located below; For a fixed value, it refers to the distance between the two ends of the second pre-compressed inclined steel spring 27 in the Y direction in the horizontal multi-stage stiffness isolator located below; The distance between the two ends of the second pre-compressed inclined steel spring 27 in the X-direction of the horizontal multi-stage stiffness isolator located below is in the X-direction.

[0103] Known This setting is achieved by adjusting the position of the second slider 25 in the lower horizontal multi-stage stiffness vibration isolator on the guide rail 3. and Changes have occurred because For a constant value, according to and The compression length of the second pre-compression inclined steel spring 27 of the horizontal multi-stage stiffness isolator located below is obtained. The compression stroke of the second pre-compression inclined steel spring 27 in the horizontal multi-stage stiffness isolator located below is obtained according to formula (2-2). .

[0104] During the adjustment process, the parameters that are known in advance are: , , , ,according to , achievable , ; will be obtained Substituting into formula (2), we obtain the required result. Then adjust the position of the second slider 25 of the horizontal multi-stage stiffness vibration isolator located below on the guide rail 3, and adjust... infinitely close This yields the preferred assembly state of the horizontal multi-stage stiffness isolator located below under the current operating conditions.

[0105] The horizontal multi-stage stiffness isolator located above, with its transmission block moving in the Y direction, has its linear stiffness coefficient of each second pre-compressed inclined steel spring 27 denoted as [missing information]. The linear stiffness coefficient of each horizontal steel spring is denoted as . The horizontal multi-stage stiffness isolator located above adjusts the stiffness ratio of the second pre-compressed inclined steel spring 27 to the horizontal steel spring. The actual pre-compression coefficient of the second pre-compression inclined steel spring 27 The compression stroke of the second pre-compressed inclined steel spring 27 in the horizontal multi-stage stiffness isolator located above. The relationship between the three parameters allows the horizontal multi-stage stiffness isolator located above to acquire different horizontal quasi-zero stiffness mechanical properties, thus achieving a multi-functional vibration isolation effect.

[0106] Specifically, to achieve the quasi-zero stiffness mechanical properties of the horizontally multi-stage stiffness vibration isolator located above... , , The three parameters satisfy formula (3), which is as follows:

[0107] (3)

[0108] In formula (3), The actual pre-compression coefficient of the second pre-compression inclined steel spring 27 in the horizontal multi-stage stiffness isolator located above. The compression stroke of the second pre-compressed inclined steel spring 27 in the horizontal multi-stage stiffness isolator located above. The calculation methods are as follows: Formula (3-1) and Formula (3-2):

[0109] (3-1)

[0110] (3-2)

[0111] In formulas (3-1) and (3-2), The set value refers to the pre-compression coefficient of the second pre-compression inclined steel spring 27 in the horizontal multi-stage stiffness isolator located above; For a fixed value, it refers to the distance between the two ends of the second pre-compressed inclined steel spring 27 in the X direction in the horizontal multi-stage stiffness isolator located above; The distance between the two ends of the second pre-compressed inclined steel spring 27 in the Y direction in the horizontal multi-stage stiffness isolator located above is the distance between the two ends of the spring in the upper direction.

[0112] Known This setting is achieved by adjusting the position of the second slider 25 in the upper horizontal multi-stage stiffness vibration isolator on the guide rail 3. and Changes have occurred because For a constant value, according to and The compression length of the second pre-compression inclined steel spring 27 of the horizontal multi-stage stiffness vibration isolator located above is obtained. The compression stroke of the second pre-compressed inclined steel spring 27 in the upper horizontal multi-stage stiffness vibration isolator is obtained according to formula (3-2). .

[0113] During the adjustment process, the parameters that are known in advance are: , , , ,according to , achievable , ; will be obtained Substituting into formula (3), we obtain the required result. Then adjust the position of the second slider 25 of the horizontal multi-stage stiffness vibration isolator located below on the guide rail 3, and adjust... infinitely close This yields the preferred assembly state of the horizontal multi-stage stiffness isolator located below under the current operating conditions.

[0114] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0115] The meaning of "and / or" as used in this application includes both situations where each exists alone or both exist simultaneously.

[0116] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0117] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load, characterized in that: This includes vertical multi-stage stiffness limiting vibration isolators and two horizontal multi-stage stiffness vibration isolators, wherein: The vertical multi-stage stiffness limiting vibration isolator includes a bearing plate (1), an upper limit plate (4), a lower limit plate (17), a vertical positive stiffness mechanism, a vertical negative stiffness mechanism, an adjusting support part, and a connecting rod (15). The bearing plate (1), the upper limit plate (4), and the lower limit plate (17) are distributed vertically and horizontally at intervals. The vertical positive stiffness mechanism is set between the bearing plate (1) and the upper limit plate (4). The vertical positive stiffness mechanism includes four vertical steel springs (2). The four vertical steel springs (2) are the elastic elements of the vertical positive stiffness mechanism. The linear stiffness coefficients of the four vertical steel springs (2) are the same. ; The vertical negative stiffness mechanism is located between the upper limit plate (4) and the lower limit plate (17). The vertical negative stiffness mechanism includes eight sets of inclined elastic components. Each elastic component is provided with a first pre-compressed inclined steel spring (11). The first pre-compressed inclined steel spring is the elastic element of the vertical negative stiffness mechanism. The linear stiffness coefficients of the eight first pre-compressed inclined steel springs (11) are the same. ; The adjustable support is positioned between the upper limit plate (4) and the lower limit plate (17); One end of the connecting rod (15) is connected to the bearing plate (1), and the other end of the connecting rod (15) passes through the upper limit plate (4) to connect the vertical positive stiffness mechanism and the vertical negative stiffness mechanism. A first central connecting block (13) is provided at the end of the connecting rod (15) away from the bearing plate (1). The first central connecting block (13) can move on the connecting rod (15). The horizontal multi-stage stiffness vibration isolator includes a connecting plate (19), a base plate (26), a horizontal negative stiffness mechanism, and a horizontal positive stiffness mechanism; The connecting plate (19) and the base plate (26) are distributed vertically. Two guide rails (23) are set on the bottom surface of the connecting plate (19) and a transmission block (29) is set in the middle of the connecting plate (19). The transmission block (29) can move linearly along the bottom surface of the connecting plate (19). Four limiting sliders (24) are set at the four corners of the top surface of the base plate (26), and two limiting sliders (24) located below the same guide rail (23) are slidably connected to the guide rail (23); A horizontal negative stiffness mechanism and a horizontal positive stiffness mechanism are provided between the base plate (26) and the connecting plate (19). The horizontal negative stiffness mechanism is provided between the four limit sliders (24), and the horizontal positive stiffness mechanism is provided on the side of the four limit sliders (24) away from the horizontal negative stiffness mechanism. The horizontal negative stiffness mechanism includes a second central connecting block (28) and four sets of second pre-compressed inclined steel springs (27). The second central connecting block (28) is mounted on the transmission block (29). The four sets of second pre-compressed inclined steel springs (27) are arranged horizontally and symmetrically around the second central connecting block (28). The linear stiffness coefficients of the four sets of second pre-compressed inclined steel springs (27) are the same. The horizontal stiffness mechanism includes two baffles (18), four sets of horizontal steel springs (21), and two second slide rods (22). The baffles (18) are set on the base plate (26) and are located on the side of the guide rail (23) facing the external environment. Each baffle (18) has a set of horizontal steel springs (21) on both sides. The four sets of horizontal steel springs (21) have the same linear stiffness coefficient. The second slide rods (22) are set parallel to the side of the guide rail (23) facing the external environment, and each second slide rod (22) passes through two sets of horizontal steel springs (21) and one baffle (18). Two horizontal multi-stage stiffness vibration isolators are arranged in a cross shape, one above the other. The vertical multi-stage stiffness limiting vibration isolator adjusts the stiffness ratio between the elastic element of the vertical negative stiffness mechanism and the elastic element of the vertical positive stiffness mechanism. The actual pre-compression coefficient of the elastic element in a vertical negative stiffness mechanism Vertical compression stroke of the elastic element in a vertical negative stiffness mechanism This achieves the vertical quasi-zero stiffness characteristic at the static equilibrium position, thus realizing the nonlinear vibration isolation effect of high static stiffness and low dynamic stiffness. To achieve the vertical quasi-zero stiffness characteristics of the three-dimensional multi-level stiffness limiting vibration isolation device, , , The three parameters satisfy formula (1), which is as follows: （1） In formula (1), ; The horizontal multi-stage stiffness isolator located below, with the direction in which its transmission block (29) can move as the X-direction, has its linear stiffness coefficient denoted as [missing information]. The linear stiffness coefficient of each horizontal steel spring (21) is denoted as ; The horizontal multi-stage stiffness isolator located below adjusts the stiffness ratio of the second pre-compressed inclined steel spring (27) to the horizontal steel spring (21). The actual pre-compression coefficient of the second pre-compression inclined steel spring (27) The compression stroke of the second pre-compressed inclined steel spring (27) in the horizontal multi-stage stiffness isolator located below. The relationship between the three parameters enables the horizontal multi-stage stiffness isolator located below to acquire different horizontal quasi-zero stiffness mechanical properties, thereby achieving a multi-functional vibration isolation effect. The horizontal multi-stage stiffness isolator located above, with its transmission block (29) moving in the Y direction, has its linear stiffness coefficient of each second pre-compressed inclined steel spring (27) in the horizontal multi-stage stiffness isolator located above denoted as . The linear stiffness coefficient of each horizontal steel spring (21) is denoted as ; The horizontal multi-stage stiffness isolator located above adjusts the stiffness ratio of the second pre-compressed inclined steel spring (27) to the horizontal steel spring (21). The actual pre-compression coefficient of the second pre-compression inclined steel spring (27) The compression stroke of the second pre-compressed inclined steel spring (27) in the upper horizontal multi-stage stiffness isolator The relationship between the three parameters enables the horizontal multi-stage stiffness vibration isolator located above to acquire different horizontal quasi-zero stiffness mechanical properties, thereby achieving a multi-functional vibration isolation effect. To achieve the horizontal quasi-zero stiffness mechanical properties of the three-dimensional multi-level stiffness limiting vibration isolation device, , , The three parameters satisfy formula (2). , , The three parameters satisfy formula (3). Formulas (2) and (3) are as follows: （2） （3） In formula (2), ; in formula (3), .

2. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 1, characterized in that: The vertical positive stiffness mechanism also includes four first slide rods (3), which are arranged between the bearing plate (1) and the upper limit plate (4); the vertical steel spring (2) is sleeved on the outer wall of the first slide rod (3), and one end of the vertical steel spring (2) is connected to the bearing plate (1), and the other end passes through the upper limit plate (4).

3. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 2, characterized in that: The adjustment support includes four support cylinders (9) and eight circular hole sliders (5). The four support cylinders (9) are supported between the upper limit plate (4) and the lower limit plate (17). Each support cylinder (9) is equipped with two circular hole sliders (5), which can slide on the support cylinder (9).

4. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 3, characterized in that: It also includes eight first sliders (7), each of which is mounted on a circular hole slider (5), and all eight first sliders (7) face the middle of the upper limit plate (4) and the lower limit plate (17); at the same time, the first sliders (7) can slide on the side wall connected to the circular hole slider (5).

5. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 4, characterized in that: The elastic component also includes a first piston rod (10) and a first piston sleeve (12). One end of the first piston rod (10) is connected to the first slider (7), and the other end is inside the first piston sleeve (12). The end of the first piston sleeve (12) away from the first piston rod (10) is connected to the first central connecting block (13). A first pre-compressed inclined steel spring (11) is sleeved on the outside of the first piston rod (10) and the first piston sleeve (12).

6. A three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 1 or 5, characterized in that: It also includes four second sliders (25), two second sliders (25) are slidably connected on each guide rail (23), and each second slider (25) is connected to a limit slider (24), while each second slider (25) is connected to a set of second pre-compressed inclined steel springs (27).

7. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 6, characterized in that: The horizontal negative stiffness mechanism also includes a second piston rod (33) and a second piston sleeve (32). One end of the second piston rod (33) is connected to the second central connecting block (28), and the other end is inside the second piston sleeve (32). The end of the second piston sleeve (32) away from the second piston rod (33) is connected to a second slider (25). A second pre-compressed inclined steel spring (27) is sleeved on the outside of the second piston sleeve (32).

8. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 7, characterized in that: It also includes four support plates (20), which are set on the side of the limiting slider (24) away from the horizontal negative stiffness mechanism, and the two ends of the second slide rod (22) are respectively connected to a support plate (20).

9. A three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 8, characterized in that: The second central connecting block (28) has a waist hole in the middle, and the transmission block (29) is located in the waist hole. The transmission block (29) moves linearly in the waist hole of the second central connecting block (28).

10. The three-dimensional multi-level stiffness limiting vibration isolation device with adjustable load according to claim 1, characterized in that: In formula (1), the actual pre-compression coefficient of the elastic element of the vertical negative stiffness mechanism is... Vertical compression stroke of the elastic element in a vertical negative stiffness mechanism The calculation methods are as follows: Formula (1-1) and Formula (1-2): （1-1） （1-2） In formulas (1-1) and (1-2), This is a set value, referring to the pre-compression coefficient of the elastic element in the vertical negative stiffness mechanism; For a fixed value, it refers to the distance between the end of the elastic element of the vertical negative stiffness mechanism near the lower limit plate (17) and the connecting rod (15) in the length direction of the lower limit plate (17); For a fixed value, it refers to the distance between the end of the elastic element of the vertical negative stiffness mechanism near the lower limit plate (17) and the connecting rod (15) in the width direction of the lower limit plate (17); This refers to the vertical distance in the vertical direction of the elastic element of the vertical negative stiffness mechanism; In formula (2), the actual pre-compression coefficient of the second pre-compression inclined steel spring (27) in the horizontal multi-stage stiffness isolator located below is... The compression stroke of the second pre-compressed inclined steel spring (27) in the horizontal multi-stage stiffness isolator located below. The calculation methods are as follows: Formula (2-1) and Formula (2-2): （2-1） （2-2） In formulas (2-1) and (2-2), The set value refers to the pre-compression coefficient of the second pre-compression inclined steel spring (27) in the horizontal multi-stage stiffness isolator located below; For a fixed value, it refers to the distance between the two ends of the second pre-compressed inclined steel spring (27) in the X direction in the horizontal multi-stage stiffness isolator located below; The distance between the two ends of the second pre-compressed inclined steel spring (27) in the X direction in the horizontal multi-stage stiffness isolator located below; In formula (3), the actual pre-compression coefficient of the second pre-compression inclined steel spring (27) in the upper horizontal multi-stage stiffness isolator is... The compression stroke of the second pre-compressed inclined steel spring (27) in the upper horizontal multi-stage stiffness isolator The calculation methods are as follows: Formula (3-1) and Formula (3-2): （3-1） （3-2） In formulas (3-1) and (3-2), The set value refers to the pre-compression coefficient of the second pre-compression inclined steel spring (27) in the horizontal multi-stage stiffness isolator located above; For a fixed value, it refers to the distance between the two ends of the second pre-compressed inclined steel spring (27) in the Y direction in the horizontal multi-stage stiffness isolator located above; The distance between the two ends of the second pre-compressed inclined steel spring (27) in the Y direction in the horizontal multi-stage stiffness isolator located above is the distance between the two ends of the spring in the upper direction.

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