CN115111507B - An adjustable vibration isolation platform with enlarged quasi-zero stiffness - Google Patents

Abstract

The present invention relates to the field of vibration isolation technology in engineering, and specifically to an adjustable vibration isolation platform with enlarged quasi-zero stiffness, which is mainly composed of an adjustment device, a U-shaped elastic structure and an X-shaped vibration isolation platform. Among them, the adjustment device can realize a labor-saving way to twist the nut through a gear amplification torque system, thereby adjusting the preload of the horizontal spring; the U-shaped elastic structure does not work within a certain horizontal motion range. When the motion amplitude increases or the load increases, the horizontal spring in the U-shaped structure will contact the bottom support, thereby generating a positive stiffness that gradually increases from zero; the entire X-shaped vibration isolation platform can achieve favorable nonlinear stiffness and damping, especially the platform will have quasi-zero stiffness or even negative stiffness under a certain load, which is not good for the stability of the structure and reduces the vibration isolation performance, while the U-shaped elastic structure device can provide a stiffness curve from zero stiffness to positive stiffness in the vertical direction.

Description

An adjustable vibration isolation platform with enlarged quasi-zero stiffness

Technical Field

The invention relates to the field of vibration isolation technology, and in particular to an adjustable nonlinear stiffness damping based on a bionic structure, a widened quasi-zero stiffness range, and a vibration isolation device and a platform with labor-saving adjustment based on gear drive.

Background technique

The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

In engineering, vibration isolation platforms are widely used, for example, in suspension systems for car seats, vibration isolation platforms for precision instruments in mechanical systems, and vibration isolation layer designs for structures in civil engineering. These vibration isolation systems can not only be used in the civil field, but can also be used in vibration protection in aerospace and military fields such as aircraft, ships, and missile launches under optimized design.

There are many vibration isolation methods in the field of vibration isolation, including passive vibration isolation, active vibration isolation and semi-active vibration isolation. Among them, passive vibration isolation technology does not consume energy, does not require the use of sensors, controllers and other equipment, and does not rely on real-time monitoring. It is safe, stable and low-cost. Under optimized design, passive vibration isolation technology can achieve the effect of active vibration isolation and can be widely used.

From the perspective of mathematical modeling and analysis, vibration isolation systems can be divided into two types: linear vibration isolation systems and nonlinear vibration isolation systems. Among them, the linear system dynamics model is simple and easy to analyze, but it has limitations and cannot deeply analyze some vibration mechanisms. At the same time, it ignores the beneficial phenomena that may be brought about by nonlinear terms. Although the modeling of nonlinear systems is more complex and the analysis is difficult, it has advantages that linear systems cannot achieve, such as in-depth analysis of the nonlinear phenomena of the system, and using these nonlinear phenomena in engineering to achieve more advantageous product performance and structural design, such as using nonlinearity to improve the vibration isolation performance of the system.

In view of the increasing requirements for vibration isolation, such as low-frequency vibration isolation, a wider vibration isolation frequency range, and the smallest resonance peak, the stiffness and damping of the vibration isolation system need to be optimized to achieve the best vibration isolation effect. In the parameter design of the linear vibration isolation system, reducing the system stiffness can achieve low-frequency vibration isolation and widen the vibration isolation frequency band, but it will lead to a decrease in the bearing capacity of the vibration isolation platform; increasing the damping coefficient will reduce the vibration amplitude of the resonance peak, but will deteriorate the vibration isolation performance in the high-frequency area. These are problems that the linear system cannot solve.

On the contrary, a nonlinear vibration isolation system under optimized design can solve the above problems and improve the overall vibration isolation performance of the entire system. For example, the geometric nonlinearity of the structure can be used to design ultra-low dynamic stiffness while improving the static bearing capacity, that is, nonlinear stiffness with high static stiffness and low dynamic stiffness (high static and low dynamic), and even quasi-zero stiffness can be achieved. At this time, the vibration isolation system can achieve ultra-low frequency vibration isolation, effective vibration isolation above 1Hz, and even full-frequency vibration isolation. However, some existing quasi-zero stiffness technologies still have some problems, such as the quasi-zero stiffness range is too narrow and unstable, and further optimization design is needed to solve these problems.

Summary of the invention

The purpose of the present invention is to provide an adjustable, widened quasi-zero stiffness range vibration isolation device, aiming to solve the technical problems existing in the prior art of passive vibration isolation devices such as too narrow quasi-zero stiffness range, unstable movement, poor bearing capacity, and difficulty in parameter adjustment.

To achieve the above object, the technical solution of the present invention is:

The present invention proposes an adjustable vibration isolation platform with enlarged quasi-zero stiffness, comprising:

An X-shaped vibration isolation platform comprises an X-shaped structure, an upper platform and a base, wherein the top of the X-shaped structure is connected to the upper platform, and the bottom is connected to the base;

An adjusting device is connected to the X-shaped structure to drive the X-shaped structure to rise and fall; by adjusting the preload of the horizontal spring, the upper platform can be raised and lowered, and the vertical stiffness of the X-shaped structure can be provided, and the stiffness can be positive, negative or zero stiffness respectively through the adjusting device;

The U-shaped elastic structure includes a U-shaped interface, a spring and a bottom support; the non-interface position of the U-shaped interface is fixed on the upper platform, and the spring is horizontally installed in the U-shaped opening; the bottom support is installed on the base, and when the spring contacts the base support, the horizontal spring generates tensile deformation, providing the system with positive stiffness in the vertical direction.

As a further technical solution, the adjusting device is an automatic driving device or a manual driving device.

As a further technical solution, the automatic drive device includes a motor and a gear transmission system connected to the motor, and a labor-saving adjustment function is achieved through the gear set.

As a further technical solution, the manual drive device includes a rotating handle and a gear transmission system connected to the handle.

As a further technical solution, the bottom support includes a fixing fixture, and a clip is clamped on the upper part of the fixing fixture. In the height direction, the relative position of the clip and the fixing fixture is adjustable.

As a further technical solution, a first axis and a second axis are provided at the bottom of the X-shaped structure, the second axis is connected to a nut, and the first axis is fixed to the base and can rotate; the nut cooperates with the threaded rod, and the adjusting device drives the threaded rod to rotate.

As a further technical solution, a horizontal spring is also included, one end of which is connected to the nut, and the other end is connected to the first axis at the bottom of the X-shaped structure.

As a further technical solution, the base includes an outer frame, on which a sliding groove cooperating with the first shaft and a fixed end for fixing the second shaft are provided.

The above-mentioned adjustment device can realize a labor-saving way to twist the nut through a gear amplification torque system, thereby adjusting the preload of the horizontal spring; the U-shaped elastic structure does not work within a certain horizontal motion range. When the motion amplitude increases or the load increases, the horizontal spring in the U-shaped structure will contact a bottom support at the bottom, thereby generating a positive stiffness that gradually increases from zero; the X-shaped vibration isolation platform is composed of an upper platform, a base and an X-shaped structure, wherein the X-shaped structure is composed of a rotating rod, a bearing, a shaft, a horizontal elastic member, etc. The entire X-shaped vibration isolation platform can achieve favorable nonlinear stiffness and damping. In particular, the X-platform will have quasi-zero stiffness or even negative stiffness under a certain load, which is not conducive to the stability of the structure and reduces the vibration isolation performance. The U-shaped elastic structure device can provide a stiffness curve from zero stiffness to positive stiffness in the vertical direction. Through optimized design, the negative stiffness of the X-shaped structure and the positive stiffness of the U-shaped elastic structure can offset each other to achieve a widened quasi-zero stiffness range, and the synthetic stiffness curve is a smooth curve.

Compared with the existing structure, the present invention has the following innovations:

(1) The stiffness adjustment device of the system adopts a gear transmission system, which makes the adjustment process more labor-saving. At the same time, there are two adjustment modes: motor drive or manual drive.

(2) The design of the gear system uses the relationship between the force transmission and torque transmission between gears to amplify the input torque to the output torque. The amplification effect can be from several times to hundreds of times. The amplification factor can be determined by the design of the gear size.

(3) The U-shaped elastic structure is designed to widen the quasi-zero stiffness range of the system, improve vibration isolation performance, and increase stability. Specifically, when the X-shaped structure is compressed or the movement amplitude reaches a certain level, the U-shaped elastic structure contacts the bottom support to generate spring tension, providing the system with a positive stiffness that slowly increases from zero, thereby offsetting the negative stiffness of the X-shaped structure at this time and widening the quasi-zero stiffness range. The core function of the U-shaped elasticity is to couple with the stiffness of the X-shaped structure to produce a smooth and continuous stiffness curve with a widened quasi-zero stiffness range.

(4) The U-shaped elastic structure will generate a gradually increasing positive stiffness after contacting the bottom support, thereby improving the bearing capacity of the system and solving the problem of instability caused by the negative stiffness of the X-shaped structure, which may collapse under large loads and large amplitudes.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is the overall design framework of the present invention;

Figure 2 is the design framework of the gear amplification system;

Fig. 3 is a model design diagram of the present invention;

Figure 4 (a) Stiffness curve of X-type structure; Figure 4 (b) Stiffness curve of X-type structure coupled with U-type elastic structure; Figure 4 (c) Vibration transmissibility at different working positions;

FIG5(a) is an enlarged quasi-zero stiffness curve under the optimized coupling of the present invention; FIG5(b) is an optimized vibration transmissibility of different working positions of the present invention;

FIG6 is a schematic diagram of a three-dimensional model of a motor drive according to the present invention;

FIG7 is a schematic diagram of a manually driven three-dimensional model of the present invention;

FIG8 is a cross-sectional view of the manual drive of the present invention;

FIG9 is a front view of a manually driven three-dimensional model of the present invention;

FIG10 is a side view of a manually driven three-dimensional model of the present invention;

FIG11 is a top view of a manually driven three-dimensional model of the present invention;

FIG12 is a front view of a three-dimensional model of a motor drive according to the present invention;

FIG13 is a side view of a three-dimensional model of a motor drive according to the present invention;

FIG14 is a top view of a three-dimensional model of a motor drive according to the present invention;

FIG15 is a schematic diagram of a gear transmission system of the present invention;

FIG16 is a schematic structural diagram of a bottom support of a U-shaped elastic structure of the present invention;

FIG17 is a schematic diagram of the structure of an X-shaped vibration isolation platform in the present invention;

FIG. 18 is a schematic diagram of the base of the X-shaped vibration isolation platform of the present invention.

In the figure:

10 adjusting device, 111 motor drive, 112 manual drive, 121 input pinion gear, 122 amplifying gear, 123 coaxial pinion gear, 124 output gear;

20 U-shaped elastic structure, 21 U-shaped interface, 22 horizontal spring, 23 bottom support;

30X type vibration isolation platform, 31X type structure, 32 mechanical device,

311 rotating rod, 312 shaft, 313 bearing, 314 horizontal elastic member;

3121 first axis, 3122 second axis, 3123 other axes;

321 upper platform, 322 base;

3211X-type structure fixed end, 3212 sliding groove, 3213 outer frame;

3221X-type structure fixed end, 3222 sliding groove, 3223 outer frame.

Detailed ways

It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise explicitly stated in the present invention, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and/or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and/or their combinations;

For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

Terminology explanation section: The terms "install", "connected", "connect", "fixed" and the like in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral whole; it can be a direct connection, or an indirect connection through an intermediate medium, it can be an internal connection between two elements, or an interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

As introduced in the background technology, in order to solve the above technical problems in view of the deficiencies existing in the prior art, the present invention proposes an adjustable vibration isolation platform with enlarged quasi-zero stiffness, which can realize adjustable stiffness and damping characteristics, labor-saving adjustment method, widened quasi-zero stiffness range, and favorable nonlinear stiffness damping, so that the vibration isolation device can achieve ultra-low frequency vibration isolation, a wider effective vibration isolation range, better stability, and stronger bearing capacity.

The adjustable vibration isolation platform with expanded quasi-zero stiffness disclosed in this embodiment is mainly composed of an adjustment device, a U-shaped elastic structure and an X-shaped vibration isolation platform. The adjustment device of the present invention realizes a labor-saving way of adjusting the stiffness of the system through a gear transmission system; the designed U-shaped elastic structure is used to increase additional equivalent positive stiffness, which is coupled with the negative stiffness of the X-shaped structure, thereby creating a wider quasi-zero stiffness range and improving structural stability.

Furthermore, the adjustment device in this embodiment is divided into two types: motor drive 111 and manual drive 112. The motor drive method disclosed in this embodiment is shown in Figures 6, 13, 14, and 15, wherein the motor drive method requires the input pinion 121 to be installed on the motor output bearing, and when the motor is started, the input pinion 121 starts to rotate and drives the amplifying gear 122 to rotate; the amplifying gear 122 and the coaxial pinion 123 are fixed at both ends of a shaft at the same time, and the output torque is amplified by the size ratio of the two gears; the coaxial pinion 123 rotates and drives the output gear 124 to rotate, and finally the output torque is amplified.

Among them, the manual driving method disclosed in this embodiment is shown in Figures 7, 8, 9, 10, and 11. The difference between the manual driving method and the motor driving method is that the amplifying gear 122 is replaced by a disc, and the motor and the input pinion 121 are omitted. The gear system can be driven by directly rotating the disc by hand, thereby finally amplifying the output torque.

Specifically, motor drive or manual drive can be selected according to actual needs, and then the gear system can be designed, including selecting the size and diameter of each gear. For example, in this embodiment, the diameter ratio of the gears is selected as: amplifying gear 122: input pinion 121 = 2, coaxial pinion 123: amplifying gear 122 = 1/2, output gear 124: coaxial pinion 123 = 2. The gear system can amplify the input torque by 4 times, that is, the output torque is four times the input torque.

Based on the above gear system, the adjusting device can amplify the torque to achieve a labor-saving way to twist the nut, thereby adjusting the preload, preload and equivalent stiffness of the horizontal spring.

The U-shaped elastic structure in this embodiment is designed to increase the positive stiffness of the system, and the coupling effect with the X-shaped structure further widens the quasi-zero stiffness range of the system and improves the stability of the system. As shown in FIG8 , the U-shaped elastic structure includes the U-shaped interface 21 , the horizontal spring 22 and the bottom support 23 .

Furthermore, the U-shaped interface 21 in this embodiment is designed to install a horizontal spring 22. When designing, it is necessary to pay attention to the size that needs to be coordinated with the horizontal spring 22. One end of the U-shaped interface 21 is fixed to the upper mechanical device 321. The U-shaped interface 21 installs the horizontal spring 22. The installation position is required to be adjustable so that the horizontal distance and position of the horizontal spring 22 can be adjusted.

The horizontal spring 22 in this embodiment is an elastic element that can have a large elastic deformation. It is not specifically a spring. In this example, a spring is selected as an example. The stiffness, length, coil diameter and other parameters of the horizontal spring 22 can be selected according to the needs, and the appropriate parameters need to be selected in accordance with the stiffness of the X-shaped structure. Further, the horizontal spring 22 can be made of elastic silicone, rubber and other materials. As long as a certain elastic modulus is met, the stretched length can be sufficient.

The bottom support 23 in this embodiment is used to contact the horizontal spring 22, so that the horizontal spring 22 is stretched and deformed, providing the system with positive stiffness in the vertical direction.

Furthermore, the height of the bottom support 23 is adjustable. After calculation and analysis, the height of the bottom support is selected. When the X-shaped structure is compressed to a certain position, the top of the bottom support 23 contacts the spring 22, triggering contact deformation and generating stiffness.

Furthermore, the bottom support 23 in this example is designed as a bottom fixing fixture with a porous clip. The porous design is to facilitate the adjustment of the installation position, thereby meeting the requirement that the bottom support 23 is height adjustable. The specific structure is shown in FIG16 , which includes a fixing fixture, a clip is installed on the fixing fixture, and a plurality of holes are provided on the clip.

In this embodiment, the X-shaped vibration isolation platform 30 is composed of the X-shaped structure 31 and the mechanical device 32, which is the main structure of the present invention.

As shown in Figure 17, the X-shaped structure 31 is composed of multiple rotating rods 311, multiple shafts 312, multiple bearings 313 and horizontal elastic members 314; in this embodiment, there are 8 rotating rods 311, and the 8 rods are arranged in two groups, with 4 rods in one group, and the two groups are symmetrical front to back; taking one group as an example for explanation, among the four rotating rods 311, two of them are cross-arranged and located at the top, and the other two are also cross-arranged and located at the bottom, and the cross position and end of the rotating rods 311 cross-arranged up and down are connected to the other group of rotating rods through the shaft 312 and the bearing 313.

The X-shaped structure 31 is characterized in that the movement in the horizontal direction is converted into the movement in the vertical direction with geometric nonlinear characteristics through the movement between the rotating rod 311, the shaft 312 and the bearing 313. Specifically, the rotating rod 311 rotates when the vibration isolation platform moves through the connection between the shaft 312 and the bearing 313, so that the bottom end of the rotating rod 311 moves horizontally. The horizontal movement has a geometric nonlinear relationship with the vertical movement of the upper platform 321 of the X-shaped vibration isolation platform, so that this nonlinear relationship is used to optimize the vibration isolation performance of the X-shaped vibration isolation platform.

The shaft 312 is composed of a first shaft 3121 at the bottom and the top, a second shaft 3122 and other shafts 3123. The second shaft 3122 at the bottom of the X-shaped structure is fixed on a nut, and the nut cooperates with the threaded rod. The above-mentioned adjustment device (motor drive 111 and manual drive 112) drives the threaded rod to rotate, and the adjustment device drives the threaded rod to rotate, and the threaded rod drives the nut to move horizontally, so that the second shaft at the bottom of the X-shaped structure approaches or moves away from the direction of the first shaft, so that the entire X-shaped structure is raised or lowered.

The horizontal elastic member 314 provides a horizontal rigidity for the X-shaped structure 31 . When the X-shaped structure 31 moves, the horizontal elastic member 314 generates stretching or compression, thereby providing the system with recoverable elastic potential energy.

In this embodiment, the horizontal elastic member 314 is a spring, one end of which is connected to the nut, and the other end is connected to the first shaft 3121, which is fixed to the base and can rotate;

Furthermore, the equivalent stiffness of the X-shaped structure will have quasi-zero stiffness and then negative stiffness when the structure is compressed to a certain degree or the vibration amplitude exceeds a certain degree. Combined with the positive stiffness of the U-shaped elastic structure 20, the negative stiffness is offset, and the quasi-zero stiffness range of the entire system is widened, while the bearing capacity is greatly improved.

The mechanical device 32 in this embodiment includes an upper platform 321 and a base 322, and its purpose is to connect and install the X-shaped structure so that the axis 312 of the X-shaped structure can slide horizontally, and the rotating rod rotates around the axis, ultimately converting horizontal movement into vertical movement.

Furthermore, the top layer of the upper platform 321 is used to place the vibration-isolating object, and the connecting plate of the top layer fixes the U-shaped elastic structure 20, and the U-shaped elastic structure 20 moves in the vertical direction following the upper platform 321; the upper platform 321 includes an X-shaped structure fixed end 3211, a sliding groove 3212, and an outer frame 3213; the X-shaped structure fixed end 3211 of the outer frame 3213 is used to fix

The bottom of the bottom support 322 is connected to the foundation or the vibration table, and the connecting plate at the bottom fixes the bottom support 23 of the U-shaped spring of the U-shaped elastic structure 20. The bottom support 322 includes an X-shaped structure fixed end 3221, a sliding groove 3222, and an outer frame 3223.

The U-shaped elastic structure 20 and the X-shaped vibration isolation platform 30 are coupled: the X-shaped vibration isolation platform 30 can achieve favorable nonlinear stiffness and damping when used alone, and achieve a better vibration isolation effect. However, the X-shaped vibration isolation platform 30 will have quasi-zero stiffness and then negative stiffness under a certain load, which is not good for the stability of the structure, and the U-shaped elastic structure 20 device can provide a stiffness curve from zero stiffness to positive stiffness in the vertical direction. Through optimized design, when the X-shaped vibration isolation platform 20 has negative stiffness, it can offset the positive stiffness of the U-shaped elastic structure 20 to achieve a widened quasi-zero stiffness range, and at the same time, this synthetic stiffness curve is a smooth curve.

Embodiments of the present invention: The design of an adjustable and enlarged quasi-zero stiffness vibration isolation platform, the assembly includes the following steps:

S1: First, design the platform size according to actual needs, and select the number of layers n of the X-shaped structure and the length L of the rotating rod used in the structure according to the required size;

S2: Use bearings or hinges to install and fix the X-shaped structure on the upper platform and base;

S3: According to the requirements of load-bearing capacity and vibration isolation performance, optimize the stiffness required by the analysis system and select the appropriate length and elastic modulus of the horizontal elastic part;

S4: Place the selected horizontal elastic member at the bottom of the X-shaped structure, connect one end to the rotating shaft, and fix the nut at the other end;

S5: Select gears according to requirements and install the gear transmission system. The center of the input pinion is fixed to the motor. The input pinion is connected to the amplifying gear to drive it to rotate. The center of the amplifying gear is fixedly connected to a shaft. The other end of the shaft is fixedly connected to the center of the coaxial pinion. The coaxial pinion drives the output large gear to rotate. The center of the output large gear is fixed to a threaded rod. The other end of the threaded rod cooperates with the nut in S4.

S6: If manual input is selected in step S5, no motor or input pinion is required, and the amplifying gear is replaced with a rotating disc, and the remaining steps are the same as S5;

S7: According to the stiffness analysis, the horizontal position of the U-shaped elastic structure and the height of the bottom support are calculated, and then the U-shaped interface is installed on the top connecting plate of the X-shaped structure and the horizontal spring is installed in the U-shaped structure;

S8: Calculate the contact level of the U-shaped elastic structure according to the requirements, adjust the height of the bottom support, and then install the bottom support of the U-shaped elastic structure on the connecting plate at the bottom of the X-shaped structure mechanical device.

S9: If necessary, select the combination of spring and damper as the horizontal elastic member and install it at the corresponding position of the X-shaped structure, which can further enhance the vibration reduction effect;

The embodiment of the present invention utilizes the nonlinear stiffness damping of the X-type structure and cooperates with the U-type elastic structure to further widen the quasi-zero stiffness range and improve the vibration isolation effect, and at the same time uses a gear transmission system to achieve a labor-saving adjustment method. The vibration isolation effect can be described by the vibration transmission rate, which is defined as the ratio of the vibration amplitude of the vibration isolation object to the external excitation amplitude. Figure 4 (a) and Figure 4 (b) show the static stiffness curve of the system and the corresponding vibration isolation performance analysis. Figure 4 (a) is the static stiffness curve of the X-type structure of the vibration isolation platform. It can be seen that when the static load continues to increase, the X-type structure will have a very narrow quasi-zero stiffness interval and then enter the negative stiffness range. When negative stiffness appears, the structure is in an unstable state and will collapse. Figure 4 (b) is the static stiffness curve of the X-type structure coupled with the U-type elastic structure. After optimization analysis, the U-shaped elastic structure is installed. When the X-shaped structure has negative stiffness, the U-shaped elastic structure contacts the bottom support to generate a positive stiffness in the vertical direction, which is coupled with the negative stiffness of the original X-shaped structure to form a new stiffness curve as shown in Figure 4(b). The quasi-zero stiffness range in the figure is expanded. At the same time, no negative stiffness appears when the load increases further, and the system is always in a stable state. This optimized static stiffness curve is a continuous and smooth synthetic stiffness curve. Figure 4(c) shows the vibration isolation performance corresponding to different working positions: vibration transmissibility curve. From the results in the figure, it can be seen that working position C is the optimal working position. At this time, the system is in the quasi-zero stiffness range, the resonance peak amplitude is the smallest, and the vibration isolation frequency range is the widest.

Figures 5(a) and 5(b) further analyze this coupling stiffness effect: the positive stiffness in the vertical direction generated by the contact between the U-shaped elastic structure and the bottom support is coupled with the negative stiffness of the original X-shaped structure to form a new stiffness curve as shown in Figure 5(a). The quasi-zero stiffness range in the figure is expanded, no negative stiffness appears, and the system is always in a stable state when the load increases further. C and D are both within the quasi-zero stiffness range. Further, the vibration isolation performance of the corresponding working positions is calculated. Four positions A, B, C, and D are selected in the static stiffness curve Figure 5(a). The transmissibility corresponding to the four working positions A, B, C, and D is shown in Figure 5(b). As shown in the figure, the transmissibility resonance peak amplitude of D is the smallest, the effective vibration isolation frequency range is the widest, and the vibration isolation effect is the best. The appearance of D depends on the coupling effect between the U-shaped elastic structure and the X-shaped structure. This coupling effect not only widens the range of quasi-zero stiffness, but also enables the structure to remain stable under large amplitude motion. The vibration isolation performance of D is better than that of C, which shows that this coupling stiffness can not only widen the quasi-zero stiffness range, but also help to reduce the resonance peak amplitude and improve the isolation performance.

The present invention has adjustable nonlinear characteristics, a widened quasi-zero stiffness range, and a labor-saving adjustment mechanism. First, through the design of the gear transmission system, a labor-saving adjustment method can be achieved, which adjusts the spring tension of the X-type structure, and the compression length to adjust the equivalent stiffness of the X-type structure. Secondly, the coupling effect of the U-shaped elastic structure and the X-type structure can achieve a widened quasi-zero stiffness range, while improving stability and load-bearing capacity. After optimized design, ultra-low frequency vibration control, ultra-wide effective vibration isolation frequency range, good motion stability, and strong static load-bearing capacity can be achieved. At the same time, the present invention has the characteristics of small size, heavy load-bearing, no energy consumption, green environmental protection, low manufacturing and processing precision requirements, and low production cost. It can be widely used in vibration reduction and vibration control of precision instruments, engineering structures, etc.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the concept and principle of the present invention should be included in the protection scope of the present invention.

The invention involved in the present invention has the following advantages and innovations based on the X-shaped structural design:

1. The adjustment device utilizes the gear transmission system to realize a labor-saving way of adjusting the pre-compression and pre-tension of the horizontal spring, thereby conveniently adjusting the system equivalent stiffness, natural frequency, vibration isolation range, etc.

2. There are two adjustment modes: motor drive and manual drive, which can be selected according to actual needs. Motor drive can also be connected to an external controller, computer, etc. to achieve remote control, while manual drive has no energy consumption, is convenient and low cost.

3. The design of the U-shaped elastic structure can provide additional equivalent positive stiffness. By adjusting the bottom support height, the timing of the positive stiffness can be controlled.

4. There is a coupling effect between the U-shaped elastic structure force and the spring force of the X-shaped structure: through optimized design, the positive stiffness of the U-shaped elastic structure can offset the negative stiffness of the X-shaped structure, thereby widening the quasi-zero stiffness range of the original X-shaped vibration isolation platform, and at the same time greatly improving the vibration isolation performance, stability and bearing capacity of the entire system.

Finally, it should be noted that relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (5)

1. An adjustable enlarged quasi-zero stiffness vibration isolation platform comprising:

The X-shaped vibration isolation platform comprises an X-shaped structure, an upper platform and a base, wherein the top of the X-shaped structure is connected with the upper platform, and the bottom of the X-shaped structure is connected with the base;

The adjusting device is connected with the X-shaped structure and drives the X-shaped structure to lift;

The U-shaped elastic structure comprises a U-shaped interface, a spring and a bottom support; the non-interface position of the U-shaped interface is fixed on the upper platform, and the spring is horizontally arranged in the U-shaped interface; the bottom support is arranged on the base, and when the spring is contacted with the base support, the spring generates tensile deformation to provide positive rigidity in the vertical direction for the system;

The bottom support comprises a fixed clamp, the upper part of the fixed clamp clamps a clamping piece, and the relative position between the clamping piece and the fixed clamp is adjustable in the height direction;

the bottom of the X-shaped structure is provided with a first shaft and a second shaft, the second shaft is connected with a nut, and the first shaft is fixed on the base and can rotate; the nut is matched with the threaded rod, and the adjusting device drives the threaded rod to rotate;

The device also comprises a horizontal spring, wherein one end of the horizontal spring is connected with the nut, and the other end of the horizontal spring is connected with a first shaft at the bottom of the X-shaped structure;

The threaded rod drives the nut to horizontally move, so that the direction of the second axial first axis at the bottom of the X-shaped structure is close to or far away from the direction of the second axial first axis, and the whole X-shaped structure is lifted or lowered;

The horizontal spring provides rigidity in the horizontal direction for the X-shaped structure, the equivalent rigidity of the X-shaped structure can generate quasi-zero rigidity after the structure is compressed to a certain degree or the vibration amplitude exceeds a certain degree, then negative rigidity is generated, positive rigidity of the U-shaped elastic structure is matched, the negative rigidity is counteracted, and the interval of the quasi-zero rigidity of the whole system is widened.

2. The adjustable amplified quasi-zero stiffness vibration isolation platform of claim 1 wherein,

The adjusting device is an automatic driving device or a manual driving device.

3. The adjustable vibration isolation platform with enlarged quasi-zero stiffness according to claim 2, wherein the automatic driving device comprises a motor and a gear transmission system connected with the motor, and the labor-saving adjusting function is realized through a gear set.

4. The adjustable amplified quasi-zero stiffness vibration isolation platform of claim 2 wherein said manual drive means comprises a rotary handle and a gear train coupled to the handle.

5. The adjustable amplified quasi-zero stiffness vibration isolation platform of claim 1 wherein said base includes an outer frame with a sliding slot for mating with the first shaft and a fixed end for securing the second shaft.