An adjustable load vertical quasi-zero stiffness limiting vibration isolation device

Abstract

The present application belongs to the technical field of structure vibration isolation and reduction, and particularly relates to a vertical quasi-zero stiffness limiting vibration isolation device with adjustable load. The device comprises a bearing plate, an upper limiting plate, a lower limiting plate, a positive stiffness mechanism, a negative stiffness mechanism, a connecting rod and an adjusting support part. The positive stiffness mechanism is arranged between the bearing plate and the upper limiting plate, and the negative stiffness mechanism and the adjusting support part are arranged between the upper limiting plate and the lower limiting plate. The adjusting support part comprises four supporting cylinders and eight round-hole sliders. The connecting rod connects the positive stiffness mechanism and the negative stiffness mechanism, and a central connecting block is arranged on the connecting rod. One end of the negative stiffness mechanism is connected with the central connecting block, and the other end is connected with a round-hole slider. By adjusting the pre-compression coefficient of the inclined elastic element of the negative stiffness mechanism, the stroke of the round-hole slider and the position of the central connecting block on the connecting rod, the quasi-zero stiffness characteristic is maintained at the initial static force balance position, and the nonlinear vibration isolation effect of high static stiffness and low dynamic stiffness is realized.

Description

Technical Field

[0001] This invention belongs to the field of structural vibration reduction and isolation technology, specifically relating to an adjustable load vertical quasi-zero stiffness limiting vibration isolation device. 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 research on quasi-zero stiffness vibration isolation devices focuses on a superstructure of a specific design mass. By pre-selecting positive and negative stiffness system parameters, the superstructure achieves quasi-zero stiffness at the static equilibrium position. However, this approach is difficult to apply in actual engineering projects when the superstructure load changes. Summary of the Invention

[0004] This invention provides an adjustable load vertical quasi-zero stiffness limiting vibration isolation device, which exhibits good low-frequency vibration isolation performance when the vertical vibration amplitude is small, and the device can be adapted to different design loads by adjusting the nut.

[0005] The technical solution adopted by this invention to solve its technical problem is: a vertical quasi-zero stiffness limiting vibration isolation device with adjustable load, comprising a bearing plate, an upper limit plate, a lower limit plate, a positive stiffness mechanism, a negative stiffness mechanism, a connecting rod, and an adjusting support, wherein:

[0006] The load-bearing plate, the upper limit plate, and the lower limit plate are arranged sequentially at intervals.

[0007] The positive stiffness mechanism is located between the bearing plate and the upper limit plate, and the negative stiffness mechanism is located between the upper limit plate and the lower limit plate.

[0008] The positive stiffness mechanism includes four sliding rods and four steel springs. The four sliding rods are positioned between the bearing plate and the upper limit plate. The four steel springs are the elastic elements of the positive stiffness mechanism, sleeved on the outer walls of the sliding rods. All four steel springs have the same stiffness coefficient. k 2;

[0009] The adjustment support is located between the upper limit plate and the lower limit plate, and the adjustment support includes four support cylinders and eight circular hole sliders.

[0010] Four supporting cylinders are positioned between the upper limit plate and the lower limit plate, limiting the distance 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.

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

[0012] The negative stiffness mechanism includes eight sets of inclined dampers. One end of each damper is connected to a central connecting block, and the other end is connected to a circular hole slider. Each damper contains a pre-compressed steel spring, which is the elastic element of the negative stiffness mechanism. The linear stiffness coefficient of the pre-compressed steel springs in all eight dampers is the same. k 1;

[0013] The vibration isolation device achieves quasi-zero stiffness characteristics at the static equilibrium position by adjusting the stiffness ratio of the elastic element in the positive stiffness mechanism and the elastic element in the negative stiffness mechanism, the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism, and the vertical compression stroke of the elastic element in the negative stiffness mechanism, thereby realizing a nonlinear vibration isolation effect with high static stiffness and low dynamic stiffness.

[0014] To achieve quasi-zero stiffness characteristics, the stiffness ratio α of the elastic element in the positive stiffness mechanism and the elastic element in the negative stiffness mechanism, and the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism are required. Vertical compression stroke of the elastic element in a negative stiffness mechanism The three parameters must satisfy formula (1);

[0015] (1)

[0016] In formula (1), .

[0017] As a further preferred embodiment of the invention, it also includes a slider, wherein the damper is connected to the circular hole slider via the slider, and the slider can slide on the side wall connected to the circular hole slider.

[0018] As a further preferred embodiment of the present invention, the shock absorber further includes a piston rod and a piston sleeve, one end of the piston rod is hinged to the slider, the other end is located inside the piston sleeve, and the end of the piston sleeve opposite to the piston rod is hinged to the central connecting block.

[0019] As a further preferred embodiment of the present invention, one end of the slide bar is detachably connected to the bearing plate, and the other end passes through the upper limit plate.

[0020] As a further preferred embodiment of the present invention, when the slider is mounted on the circular hole slider, the slider needs to slide vertically on the circular hole slider.

[0021] As a further preferred embodiment of the present invention, one end of the connecting rod is detachably connected to the bearing plate, and the other end passes through the upper limit plate. The end of the connecting rod away from the bearing plate is provided with a threaded section, and the central connecting block is installed on the threaded section.

[0022] As a further preferred embodiment of the present invention, it also includes two nuts, which are disposed on the threaded section of the connecting rod and distributed on both sides of the central connecting block, and the position of the central connecting block on the connecting rod is adjusted by the two nuts.

[0023] As a further preferred embodiment of the present invention, the distance between the upper limit plate and the lower limit plate restricts the compression displacement stroke of the negative stiffness mechanism. The compression amount and vertical compression stroke of the elastic element of the negative stiffness mechanism are adjusted and limited by adjusting the distance between the two circular hole sliders on the support cylinder.

[0024] As a further preferred embodiment of the present invention, adjusting the position of the slider on the circular hole slider can enable secondary adjustment of the compression amount and vertical compression stroke of the elastic element of the negative stiffness mechanism.

[0025] As a further preferred embodiment of the present invention, in formula (1), the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism is... Vertical compression stroke of elastic element in negative stiffness mechanism The calculation methods are as follows: Formula (2) and Formula (3):

[0026] (2)

[0027] (3)

[0028] In formulas (2) and (3), Let be the pre-compression coefficient of the elastic element in the set negative stiffness mechanism, 'a' be the distance from the end of the elastic element connected to the circular hole slider in the negative stiffness mechanism to the connecting rod in the length direction of the lower limit plate, 'b' be the distance from the end of the elastic element connected to the circular hole slider in the negative stiffness mechanism to the connecting rod in the width direction of the lower limit plate, and 'h' be the vertical distance between the two ends of the elastic element in the negative stiffness mechanism in the vertical direction.

[0029] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art:

[0030] 1. Under different design loads, the vibration isolation device can maintain quasi-zero stiffness characteristics at the initial static equilibrium position by adjusting the pre-compression coefficient of the inclined pre-compression steel spring of the negative stiffness mechanism, the stroke of the circular hole slider, and the position of the central connecting block on the connecting rod, thereby achieving a nonlinear vibration isolation effect with high static stiffness and low dynamic stiffness.

[0031] 2. The spacing between the upper and lower limiting plates of the device of the present invention restricts the compression displacement stroke of the negative stiffness mechanism, so that the vibration isolation device does not fail due to excessive displacement of the elastic element, and effectively improves the stability of the vibration isolation system.

[0032] 3. This invention can inject liquid viscous damping into the piston rod and use the turbulence of the damping liquid to absorb energy. The additional damping works in conjunction with the steel spring to solve the problem of vertical displacement amplification caused by single quasi-zero stiffness, so that the displacement can be effectively controlled.

[0033] 4. By adjusting the screw on the circular hole slider, the relative position of the slider on the circular hole slider can be changed, which allows the elastic element of the negative stiffness mechanism to move in different compression displacement ranges, so that the system can obtain different mechanical properties. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0036] Figure 2 This is an exploded view of the overall structure of the present invention;

[0037] Figure 3 This is a schematic diagram showing the connection relationship between the vibration damper and the adjusting support of the present invention;

[0038] Figure 4 This is a schematic diagram of the parameter markings in formulas (1) to (3) of this invention.

[0039] In the diagram: 1-Bearing plate, 2-Steel spring, 3-Upper limit plate, 4-Round hole slider, 5-Support cylinder, 6-Bolt, 7-Slider, 8-Center connecting block, 9-Pre-compressed steel spring, 10-Piston sleeve, 11-Piston rod, 12-Screw, 13-Lower limit plate, 14-Connecting rod, 15-Nut, 16-Threaded screw. Detailed Implementation

[0040] 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.

[0041] 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. Example 1

[0042] This embodiment provides a preferred implementation, a vertical quasi-zero stiffness limiting vibration isolation device with adjustable load, such as... Figures 1 to 4 As shown, this vibration isolation device includes a bearing plate 1, an upper limit plate 3, a lower limit plate 13, a positive stiffness mechanism, an adjusting support, a connecting rod 14, and a negative stiffness mechanism, wherein:

[0043] The aforementioned bearing plate 1, upper limit plate 3, and lower limit plate 13 are arranged sequentially at intervals. A positive stiffness mechanism is located between the bearing plate 1 and the upper limit plate 3, and a negative stiffness mechanism is located between the upper limit plate 3 and the lower limit plate 13.

[0044] The aforementioned positive stiffness mechanism includes four sliding rods and four steel springs 2. The four sliding rods are positioned between the bearing plate 1 and the upper limit plate 3. One end of each sliding rod is detachably connected to the bearing plate 1, and the other end passes through the upper limit plate 3. The sliding rods maintain the stability of the steel springs 2 during compression. Preferably, the four sliding rods are symmetrically distributed between the bearing plate 1 and the upper limit plate 3, with the center of the space between them as the center, to prevent uneven compression of the bearing plate 1 after the placement of vibration isolation objects, which could lead to torsion or overturning. The four steel springs 2 all have the same stiffness coefficient. k 2. The steel spring 2 is the elastic element of the positive stiffness mechanism. The steel spring 2 is sleeved on the outer wall of the slide rod, and one end of the steel spring 2 is in contact with the bearing plate 1, and the other end is in contact with the upper limit plate 3.

[0045] Preferably, the inner diameter of the steel spring 2 is 1mm to 2mm larger than the inner diameter of the slide rod. A diameter greater than 2mm will cause instability during compression of the steel spring 2, while a diameter less than 1mm will cause unnecessary friction during compression. The upper and lower ends of the 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 3. A nylon sleeve or linear bearing can be added to the part of the slide rod that passes through the upper limit plate 3 to reduce friction during vertical compression.

[0046] The aforementioned adjusting support is located between the upper limit plate 3 and the lower limit plate 13. The adjusting support includes four supporting cylinders 5 and eight circular hole sliders 4. The four supporting cylinders 5 are supported between the upper limit plate 3 and the lower limit plate 13, limiting the distance between them. Each supporting cylinder 5 is equipped with two circular hole sliders 4, which can slide on the supporting cylinder 5. The distance between the upper limit plate 3 and the lower limit plate 13 restricts the compression displacement stroke of the negative stiffness mechanism. The compression amount and vertical compression stroke of the elastic element of the negative stiffness mechanism are adjusted by adjusting the distance between the two circular hole sliders 4 on the supporting cylinder 5. The circular hole sliders 4 are equipped with lead screws 16, which can be used to fix or allow the circular hole sliders 4 to slide on the supporting cylinders 5.

[0047] The aforementioned negative stiffness mechanism includes eight sets of inclined dampers. One end of each damper is connected to a central connecting block 8, and the other end is connected to a circular hole slider 4. Each damper includes a pre-compressed steel spring 9, which is the elastic element of the negative stiffness mechanism. The linear stiffness coefficient of the pre-compressed steel springs in all eight dampers is the same. k 1. When the circular hole slider 4 slides on the supporting cylinder 5, the pre-compression steel spring 9 of the negative stiffness mechanism will only be in two states: the pre-compression is released to 0 and the pre-compression continues to increase. The pre-compression steel spring 9 will not change from compression to tension. When the circular hole slider 4 is fixed on the supporting cylinder 5, the pre-compression steel spring 9 of the 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 this vibration isolation device to obtain different mechanical properties for application in different engineering practices.

[0048] One end of the connecting rod 14 is detachably connected to the bearing plate 1, and the other end passes through the upper limit plate 3 to connect the positive stiffness mechanism and the negative stiffness mechanism in parallel. The end of the connecting rod 14 facing away from the bearing plate 1 has a threaded section, and the central connecting block 8 is mounted on the threaded section. This embodiment also includes two nuts 15, which are disposed on the connecting rod 14 and distributed on both sides of the central connecting block 8. The position of the central connecting block 8 on the connecting rod 14 is adjusted by the two nuts 15. Figure 1 and Figure 4 (The connecting rod 14 between the middle bearing plate 1 and the upper limit plate 3 is not shown)

[0049] One end of the connecting rod 14 is detachably connected to the bearing plate 1 to facilitate disassembly and easy replacement of the elastic elements of the positive and negative stiffness mechanism. The nut 15 can be adjusted according to the different masses of the vibration isolation objects placed on the bearing plate 1. After adjustment, it contacts the upper and lower surfaces of the central connecting block 8, so that the positive and negative stiffness mechanisms are connected in parallel, realizing the adjustable load characteristics of this vibration isolation device for application in different vibration isolation scenarios.

[0050] The aforementioned vibration damper also includes a piston rod 11 and a piston sleeve 10. One end of the piston rod 11 is hinged to the slider 7, and the other end is located inside the piston sleeve 10. The end of the piston sleeve 10 facing away from the piston rod 11 is hinged to the central connecting block 8. Preferably, a viscous damping fluid is provided in the space between the piston rod 11 and the piston sleeve 10, utilizing the turbulence of the damping fluid to absorb energy. The additional damping, in conjunction with the pre-compressed steel spring 9, solves the problem of vertical displacement amplification caused by a single quasi-zero stiffness, thus effectively controlling the displacement.

[0051] Among them, the pre-compression steel spring 9 uses elastic elements with the same stiffness characteristics and compression coefficient, which simplifies the device parameters to facilitate the achievement of quasi-zero stiffness characteristics. The design of the quasi-zero stiffness characteristics of the vibration isolation device mainly depends on three parameters: the stiffness ratio of the positive stiffness mechanism steel spring 2 to the negative stiffness mechanism pre-compression steel spring 9, the actual pre-compression coefficient of the negative stiffness mechanism pre-compression steel spring 9, and the vertical compression stroke of the negative stiffness mechanism pre-compression steel spring 9. 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.

[0052] This embodiment also includes a slider 7. The damper is connected to the circular hole slider 4 via the slider 7. The slider 7 can slide on the side wall connected to the circular hole slider 4, and the position of the slider 7 on the circular hole slider 4 is limited by the screw 12. When the slider 7 is installed on the circular hole slider 4, the slider 7 needs to slide vertically on the circular hole slider 4. Adjusting the position of the slider 7 on the circular hole slider 4 allows for secondary adjustment of the compression amount and vertical compression stroke of the elastic element of the negative stiffness mechanism.

[0053] Under the action of ground movement or vertical vibration of isolated objects, the negative stiffness mechanism and the positive stiffness mechanism simultaneously generate vertical compression motion through the connection of link 14. The vibration isolation device adjusts the stiffness ratio of the elastic element in the positive stiffness mechanism and the elastic element in the negative stiffness mechanism, the pre-compression coefficient of the elastic element in the negative stiffness mechanism, and the vertical compression stroke of the elastic element in the negative stiffness mechanism to achieve quasi-zero stiffness characteristics at the static equilibrium position, thereby achieving a nonlinear vibration isolation effect with high static stiffness and low dynamic stiffness.

[0054] Specifically, to achieve quasi-zero stiffness characteristics, the stiffness ratio α of the elastic element in the positive stiffness mechanism and the elastic element in the negative stiffness mechanism, and the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism are... Vertical compression stroke of the elastic element in a negative stiffness mechanism The three parameters must satisfy formula (1);

[0055] (1)

[0056] In formula (1), The actual pre-compression coefficient of the elastic element in a negative stiffness mechanism Vertical compression stroke of elastic element in negative stiffness mechanism The calculation methods are as follows: Formula (2) and Formula (3):

[0057] (2)

[0058] (3)

[0059] In formulas (2) and (3), 'a' is a set value, which is the pre-compression coefficient of the elastic element in the negative stiffness mechanism. 'a' is a fixed value, which refers to the distance from the end of the elastic element in the negative stiffness mechanism connected to the circular hole slider to the connecting rod in the length direction of the lower limit plate. 'b' is a fixed value, which refers to the distance from the end of the elastic element in the negative stiffness mechanism connected to the circular hole slider to the connecting rod in the width direction of the lower limit plate. 'h' is the vertical distance between the two ends of the elastic element in the negative stiffness mechanism in the vertical direction.

[0060] Known This setting value is changed by adjusting the stroke of the circular hole slider 4 on the supporting cylinder 5 and / or the position of the central connecting block 8 on the connecting rod 14, thus altering h. Since a and b are constants, the straight-line distance between the end of the pre-compressed steel spring 9 connected to the circular hole slider 4 and the axis of the connecting rod 14 is... According to h and The compression length of the pre-compression steel spring 9 is obtained. The vertical compression stroke of the elastic element in the negative stiffness mechanism can be obtained according to formula (3). .

[0061] To achieve near-zero stiffness characteristics, the following parameters are known in advance during the adjustment process: a, b k 1. k 2. According to k 1. k 2 gives α, Substituting the obtained α into formula (1), we get the desired result. Then adjust the stroke of the circular hole slider 4 on the supporting cylinder 5 and / or the position of the central connecting block 8 on the connecting rod 14, adjusting h to be infinitely close to... Then, by adjusting the position of slider 7 on the circular hole slider 4, The optimal assembly state of this vibration reduction device under the current working conditions is obtained.

[0062] 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.

[0063] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0064] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0065] 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 vertical quasi-zero stiffness limiting vibration isolation device with adjustable load, characterized in that: Includes a bearing plate (1), an upper limit plate (3), a lower limit plate (13), a positive stiffness mechanism, a negative stiffness mechanism, a connecting rod (14), and an adjusting support, wherein: The bearing plate (1), the upper limit plate (3), and the lower limit plate (13) are distributed vertically and vertically at intervals. The positive stiffness mechanism is set between the bearing plate (1) and the upper limit plate (3), and the negative stiffness mechanism is set between the upper limit plate (3) and the lower limit plate (13); The positive stiffness mechanism includes four sliding rods and four steel springs (2). The four sliding rods are arranged between the bearing plate (1) and the upper limit plate (3). The four steel springs (2) are the elastic elements of the positive stiffness mechanism. The steel springs (2) are sleeved on the outer wall of the sliding rods. The stiffness coefficients of the four steel springs (2) are the same. k 2; The adjustment support is located between the upper limit plate (3) and the lower limit plate (13). The adjustment support includes four support cylinders (5) and eight circular hole sliders (4). Four supporting cylinders (5) are supported between the upper limit plate (3) and the lower limit plate (13), limiting the distance between the upper limit plate (3) and the lower limit plate (13). Each supporting cylinder (5) is equipped with two circular hole sliders (4), which can slide on the supporting cylinder (5). One end of the connecting rod (14) is connected to the bearing plate (1), and the other end passes through the upper limit plate (3) to connect the positive stiffness mechanism and the negative stiffness mechanism. A central connecting block (8) is provided at the end of the connecting rod (14) away from the bearing plate (1). The negative stiffness mechanism includes eight sets of inclined dampers. One end of each damper is connected to a central connecting block (8), and the other end is connected to a circular hole slider (4). Each damper contains a pre-compressed steel spring (9), which is the elastic element of the negative stiffness mechanism. The linear stiffness coefficients of the pre-compressed steel springs (9) in the eight dampers are the same. k 1; The vibration isolation device achieves quasi-zero stiffness characteristics at the static equilibrium position by adjusting the stiffness ratio of the elastic element in the positive stiffness mechanism and the elastic element in the negative stiffness mechanism, the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism, and the vertical compression stroke of the elastic element in the negative stiffness mechanism, thereby realizing a nonlinear vibration isolation effect with high static stiffness and low dynamic stiffness. To achieve quasi-zero stiffness characteristics, the stiffness ratio α of the elastic element in the positive stiffness mechanism and the elastic element in the negative stiffness mechanism, and the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism are required. Vertical compression stroke of the elastic element in a negative stiffness mechanism The three parameters must satisfy formula (1): （1） In formula (1), .

2. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 1, characterized in that: It also includes a slider (7), the damper is connected to the round hole slider (4) through the slider (7), and the slider (7) can slide on the side wall connected to the round hole slider (4).

3. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 2, characterized in that: The damper also includes a piston rod (11) and a piston sleeve (10). One end of the piston rod (11) is hinged to the slider (7), and the other end is inside the piston sleeve (10). The end of the piston sleeve (10) away from the piston rod (11) is hinged to the central connecting block (8).

4. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 1, characterized in that: One end of the slide bar is detachably connected to the bearing plate (1), and the other end passes through the upper limit plate (3).

5. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 2, characterized in that: When the slider (7) is installed on the circular hole slider (4), the slider (7) needs to slide vertically on the circular hole slider (4).

6. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 2, characterized in that: One end of the connecting rod (14) is detachably connected to the bearing plate (1), and the other end passes through the upper limit plate (3). The end of the connecting rod (14) away from the bearing plate (1) is provided with a threaded section, and the central connecting block (8) is installed on the threaded section.

7. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 6, characterized in that: It also includes two nuts (15), which are set on the connecting rod (14) and distributed on both sides of the central connecting block (8). The position of the central connecting block (8) on the connecting rod (14) is adjusted by the two nuts (15).

8. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 2, characterized in that: The distance between the upper limit plate (3) and the lower limit plate (13) restricts the compression displacement stroke of the negative stiffness mechanism. The compression amount and vertical compression stroke of the elastic element of the negative stiffness mechanism are adjusted by adjusting the distance between the two circular hole sliders (4) on the support cylinder (5).

9. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 8, characterized in that: By adjusting the position of the slider (7) on the circular hole slider (4), the compression amount of the elastic element of the negative stiffness mechanism and the vertical compression stroke of the elastic element of the negative stiffness mechanism can be adjusted twice.

10. The adjustable load vertical quasi-zero stiffness limiting vibration isolation device according to claim 1, characterized in that: In formula (1), the actual pre-compression coefficient of the elastic element in the negative stiffness mechanism is... Vertical compression stroke of elastic element in negative stiffness mechanism The calculation methods are as follows: Formula (2) and Formula (3): （2） （3） In formulas (2) and (3), The pre-compression coefficient of the elastic element in the set negative stiffness mechanism is given by: a is the distance from the end of the elastic element in the negative stiffness mechanism connected to the circular hole slider (4) to the connecting rod (14) in the length direction of the lower limit plate (13); b is the distance from the end of the elastic element in the negative stiffness mechanism connected to the circular hole slider (4) to the connecting rod (14) in the width direction of the lower limit plate (13); and h is the vertical distance between the two ends of the elastic element in the negative stiffness mechanism in the vertical direction.

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