A multi-directional vibration absorber with negative stiffness adjustment function

Abstract

The present application relates to the technical fields of vibration control and isolation, and particularly relates to a multi-directional vibration absorber with negative stiffness adjustment function, comprising a shell, a mass block is arranged in the shell, the mass block top, the mass block bottom and the shell inner wall are connected through a first elastic element, the two sides of the mass block and the shell inner wall are connected through a second elastic element, a negative stiffness adjustment mechanism is arranged between the mass block and the shell, and the first elastic element connection and the second elastic element connection are configured in a compression state. Through the cooperative work of the vertical spring and the lateral hinge inclined rod linkage mechanism, the multi-dimensional vibration absorption function in the vertical and horizontal directions is realized; meanwhile, the adjustable buckling beam structure is introduced to provide the negative stiffness characteristic, the equivalent stiffness and the natural frequency of the system are adjusted by adjusting the pre-tightening degree of the buckling beam through the adjusting knob, the system dynamic stiffness is reduced, and the low-frequency vibration isolation performance is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of vibration control and vibration isolation technology, and in particular to a multi-directional vibration absorber with negative stiffness adjustment function. Background Technology

[0002] Vibration control is a key technology for ensuring the normal operation and accuracy of equipment in fields such as precision instruments, aerospace equipment, ship equipment, and precision machining. As modern equipment develops towards higher precision and reliability, the performance requirements for vibration reduction and isolation systems are increasing. Traditional passive vibration absorbers typically employ a mass-spring-damping system, tuned to a specific frequency to suppress the vibration response of the structure. However, traditional linear vibration absorbers are limited by their positive stiffness characteristics, resulting in bottlenecks in low-frequency vibration isolation: to obtain a lower natural frequency, the spring stiffness needs to be reduced or the mass of the absorber increased, but excessively low stiffness sacrifices the system's static load-bearing capacity, while excessive mass increases the size and weight of the device, making it difficult to meet the lightweight and compact requirements of practical engineering.

[0003] To address the challenge of low-frequency vibration isolation, quasi-zero stiffness isolation technology has garnered significant attention in recent years. Its core idea is to use positive and negative stiffness elements in parallel, causing the system's equivalent dynamic stiffness near its static equilibrium position to approach zero. This achieves an extremely low dynamic natural frequency while maintaining sufficient static load-bearing capacity, resulting in excellent low-frequency vibration isolation performance. Existing quasi-zero stiffness devices often employ tilting springs, permanent magnets, or buckling beams to achieve negative stiffness, but most are designed only for a single direction (usually the vertical), making it difficult to simultaneously address vibration suppression requirements in the horizontal direction. In practical engineering, vibration excitation is often multi-directional, and single-directional isolation is insufficient to meet the multi-dimensional vibration reduction requirements under complex working conditions.

[0004] Chinese patent document CN111981075A proposes a quasi-zero stiffness vibration isolation system with bending moment resistance. It achieves resistance to bending moment and lateral impact loads through a multi-layered lateral support layout and variable dampers, providing low-frequency multi-directional vibration isolation across nearly the entire frequency range. However, the negative stiffness characteristic of this scheme mainly relies on the geometric nonlinearity of the lateral support structure, lacking an actively adjustable negative stiffness mechanism. Therefore, it cannot flexibly adjust the system's equivalent stiffness and natural frequency according to changes in the external excitation frequency.

[0005] Chinese patent document CN121719867A proposes a noise-reducing buckling beam quasi-zero stiffness low-frequency vibration isolator and its application method. By arranging multiple integral quasi-zero stiffness structural units in a ring between a base plate and a composite damping plate, the high static stiffness and low dynamic stiffness characteristics of the buckling beam structure, combined with the energy dissipation and noise reduction effects of the rubber dust cover and the composite damping plate, achieve a certain load-bearing capacity and low-frequency vibration isolation effect. However, the quasi-zero stiffness structure in this scheme is a fixed, integrated design. The negative stiffness characteristics of the buckling beam are fixed after manufacturing, lacking an adjustable pre-tightening mechanism to change the system's equivalent stiffness and natural frequency, making it difficult to flexibly tune for external excitations of different frequencies. Furthermore, its vibration isolation direction is mainly vertical, limiting its vibration isolation effect when facing multi-directional composite vibration excitations.

[0006] Therefore, there is an urgent need for a new type of vibration absorber that combines multi-directional vibration absorption capability with adjustable negative stiffness. This absorber can provide effective vibration suppression in both horizontal and vertical directions, and can also reduce the dynamic stiffness of the system by using negative stiffness compensation to achieve high-efficiency vibration isolation in a wide frequency band, especially in the low frequency band, while maintaining a compact structure and adjustable parameters to meet the needs of different working conditions and application scenarios. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-directional vibration absorber with negative stiffness adjustment function to solve the above-mentioned problems. This vibration absorber comprehensively utilizes the principles of positive stiffness support and negative stiffness compensation. Through the coordinated work of the vertical spring and the lateral hinge diagonal rod linkage mechanism, it realizes multi-dimensional vibration absorption function in the vertical and horizontal directions. At the same time, an adjustable buckling beam structure is introduced to provide negative stiffness characteristics. By adjusting the knob to change the preload of the buckling beam, the equivalent stiffness and natural frequency of the system can be adjusted, thereby reducing the dynamic stiffness of the system and significantly improving the low-frequency vibration isolation performance.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] A multi-directional vibration absorber with negative stiffness adjustment function includes a housing, a mass block is provided inside the housing, the top and bottom of the mass block are connected to the inner wall of the housing through a first elastic element, the two sides of the mass block are connected to the inner wall of the housing through a second elastic element, and a negative stiffness adjustment mechanism is provided between the mass block and the housing, wherein the first elastic element connection and the second elastic element connection are configured to be in a compressed state.

[0010] Preferably, the first elastic element includes an upper connecting spring and a lower connecting spring, an upper base is fixedly connected to the top wall of the outer shell, the upper connecting spring is fixedly installed in the upper base, and the other end of the upper connecting spring is fixedly connected to the outer shell;

[0011] The bottom wall of the outer shell is fixedly connected to a lower base, one end of the lower connecting spring is fixedly connected inside the lower base, and the other end of the lower connecting spring is fixedly connected to the outer shell.

[0012] Preferably, the second elastic element includes a guide rod, with retaining rings fixedly connected to both ends of the guide rod, and sliders symmetrically sleeved on the guide rod. A spring-loaded element is provided between the slider and the retaining rings, and the displacement of the slider is transmitted to the mass block and the outer shell.

[0013] Preferably, the rebound element is an adjusting spring, which is sleeved on the guide rod, and both ends of the adjusting spring abut against the slider and the retaining ring, respectively.

[0014] Preferably, the slider is symmetrically hinged with a diagonal rod, and the end of the diagonal rod away from the slider is hinged to a fixing device, one of the fixing devices being fixedly connected to the inner sidewall of the outer shell, and the other fixing device being fixedly connected to the sidewall of the mass block.

[0015] Preferably, the negative stiffness adjustment mechanism includes an adjustment knob movably disposed on the outer side wall of the housing, the adjustment knob being threadedly connected to a buckling beam, the buckling beam being fixedly connected to the side wall of the mass block, and the adjustment knob abutting against the outer side wall of the housing.

[0016] The present invention has the following technical effects:

[0017] (1) This invention overcomes the fundamental limitations of traditional dynamic vibration absorbers in terms of vibration isolation, frequency bandwidth, and stiffness characteristics by organically integrating the first elastic element with the second elastic element at the system level. In terms of vibration isolation, the coordinated layout of the vertical spring and the lateral hinge diagonal rod linkage mechanism achieves synchronous suppression of vertical and horizontal bidirectional vibrations in a single compact structure. In terms of frequency bandwidth, the parallel principle of positive and negative stiffness allows the equivalent dynamic stiffness of the system to be continuously adjusted to near zero, significantly expanding the effective vibration isolation frequency band from the mid-high frequency band to the low frequency and even ultra-low frequency band. In terms of stiffness characteristics, it achieves an ideal stiffness match of high static and low dynamic stiffness—the static bearing capacity is not weakened by the introduction of negative stiffness, while the dynamic stiffness can be reduced to near zero. The above three technological breakthroughs make this invention significantly superior to the prior art in terms of structural form, performance indicators, and adaptability to working conditions.

[0018] (2) Multi-directional vibration absorption capability: Through the coordinated design of the vertical connecting spring and the lateral hinge diagonal rod linkage mechanism, the synchronous suppression of vertical and horizontal vibrations is achieved. The upper and lower connecting springs are responsible for absorbing the vertical vibration energy, while the linkage mechanism composed of the diagonal rods, sliders, guide rods and adjusting springs on the left and right sides effectively offsets the horizontal vibration impact, solving the problem that traditional vibration absorbers can only cope with vibrations in one direction.

[0019] (3) Adjustable negative stiffness: A buckling beam is introduced as a negative stiffness element. The negative stiffness characteristic exhibited by the buckling beam when approaching the critical buckling load is utilized. It is connected in parallel with the positive stiffness of the vertical connecting spring and the lateral adjusting spring to achieve a significant reduction in the equivalent dynamic stiffness of the system. By applying axial preload to the buckling beam through the adjustment knobs on the left and right sides of the outer shell, the bending deformation and the magnitude of the negative stiffness of the buckling beam can be continuously changed, thereby adjusting the equivalent natural frequency of the system to adapt to vibration excitation of different frequencies, especially low-frequency vibration.

[0020] (4) Excellent low-frequency vibration isolation performance: When the negative stiffness of the buckling beam and the stiffness of the positive stiffness spring are matched at the static equilibrium position, the equivalent dynamic stiffness of the system approaches zero and the natural frequency is greatly reduced. It can achieve efficient isolation of low-frequency and even ultra-low-frequency vibrations while maintaining sufficient static load capacity.

[0021] (5) Compact structure and adjustable parameters: The modular design integrates the vertical spring, the lateral hinge diagonal rod linkage mechanism and the buckling beam negative stiffness mechanism into the same shell frame, resulting in a compact structure and small space occupation. The stiffness parameters of each component can be independently adjusted by changing the spring specifications, adjusting the position of the retaining ring or the preload of the knob, etc., to adapt to complex and ever-changing working conditions.

[0022] (6) Flexible movement and high reliability: The lateral hinge diagonal rod linkage mechanism adopts hinge connection, which is flexible in movement and sensitive in response; the sliding cooperation between the slider and the guide rod ensures accurate movement trajectory; the buckling beam adjustment mechanism adopts threaded knob transmission, which has high adjustment accuracy and reliable locking.

[0023] (7) Simple overall structure and wide applicability: The vibration absorber adopts an integrated layout within the outer shell frame. The upper and lower bases are used to fix and connect the protected equipment and the vibration source, respectively. The vertical spring, lateral hinge diagonal rod linkage mechanism and buckling beam negative stiffness mechanism are symmetrically arranged around the central mass block, resulting in balanced force and convenient installation. The fully mechanical structure requires no external energy supply or complex controllers or complex hydraulic or electromagnetic drive components, making maintenance simple and highly reliable. It has low manufacturing cost and strong environmental adaptability, and can be widely used in vibration reduction and isolation of various vibration-sensitive systems such as precision instruments, aerospace equipment, ship equipment and industrial machinery. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1This is a three-dimensional structural diagram of a multi-directional vibration absorber with negative stiffness adjustment function according to an embodiment of the present invention;

[0026] Figure 2 This is a detailed drawing of the lateral hinge diagonal linkage mechanism according to an embodiment of the present invention;

[0027] Figure 3 This is a front view of the three-dimensional structure of the vibration absorber according to an embodiment of the present invention;

[0028] Figure 4 This is a detailed drawing of the buckling beam negative stiffness adjustment mechanism according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of a multi-directional vibration absorber with negative stiffness adjustment function according to an embodiment of the present invention;

[0030] Figure 6 This is a comparison of the transmission rate curves of a traditional linear vibration absorber and the multi-directional vibration absorber of this invention.

[0031] The components are: 1. Mass block; 2. Upper connecting spring; 3. Lower connecting spring; 4. Upper base; 5. Lower base; 6. Outer shell; 7. Fixing device; 8. Inclined rod; 9. Hinge; 10. Slider; 11. Guide rod; 12. Retaining ring; 13. Adjusting spring; 14. Buckling beam; 15. Adjusting knob. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Reference Figures 1 to 6 As shown, this embodiment provides a multi-directional vibration absorber with negative stiffness adjustment function, including a housing 6, a mass block 1 inside the housing 6, the top and bottom of the mass block 1 being connected to the inner wall of the housing 6 by a first elastic member, the two sides of the mass block 1 being connected to the inner wall of the housing 6 by a second elastic member, and a negative stiffness adjustment mechanism being provided between the mass block 1 and the housing 6, wherein the first elastic member connection and the second elastic member connection are configured in a compressed state.

[0035] The scheme is further optimized. The first elastic element includes an upper connecting spring 2 and a lower connecting spring 3. An upper base 4 is fixedly connected to the top wall of the outer shell 6. The upper connecting spring 2 is fixedly installed inside the upper base 4. The other end of the upper connecting spring 2 is fixedly connected to the outer shell 6.

[0036] The bottom wall of the outer shell 6 is fixedly connected to the lower base 5. One end of the lower connecting spring 3 is fixedly connected inside the lower base 5, and the other end of the lower connecting spring 3 is fixedly connected to the outer shell 6.

[0037] In a further optimized design, the second elastic element includes a guide rod 11, with retaining rings 12 fixedly connected to both ends of the guide rod 11. A slider 10 is symmetrically sleeved on the guide rod 11, and a spring-loaded element is provided between the slider 10 and the retaining rings 12. The displacement of the slider 10 is transmitted to the mass block 1 and the outer shell 6.

[0038] The design is further optimized so that the rebound element is an adjusting spring 13, which is sleeved on the guide rod 11, and the two ends of the adjusting spring 13 abut against the slider 10 and the retaining ring 12 respectively.

[0039] In a further optimized design, a diagonal rod 8 is symmetrically hinged to the slider 10. The end of the diagonal rod 8 away from the slider 10 is hinged to a fixing device 7 via a hinge 9. One fixing device 7 is fixedly connected to the inner wall of the outer shell 6, and the other fixing device 7 is fixedly connected to the side wall of the mass block 1.

[0040] The scheme is further optimized. The negative stiffness adjustment mechanism includes an adjustment knob 15 that is movably located on the outer side wall of the outer shell 6. The adjustment knob 15 is threadedly connected to a buckling beam 14, which is fixedly connected to the side wall of the mass block 1. The adjustment knob 15 abuts against the outer side wall of the outer shell 6.

[0041] Both the upper connecting spring 2 and the lower connecting spring 3 are cylindrical helical compression springs made of spring steel. The upper end of the upper connecting spring 2 is fixed in the spring mounting seat on the lower end face of the upper base 4, and the lower end is fixed in the spring mounting seat on the upper end face of the mass block 1. The lower end of the lower connecting spring 3 is fixed in the spring mounting seat on the upper end face of the lower base 5, and the upper end is fixed in the spring mounting seat on the lower end face of the mass block 1. The upper connecting spring 2 and the lower connecting spring 3 are symmetrically arranged at both ends of the mass block 1 in the vertical direction, jointly providing the system's vertical stiffness. When external vibration excitation causes the mass block 1 to displace vertically, the upper connecting spring 2 and the lower connecting spring 3 generate elastic restoring forces opposite to the direction of displacement, converting the vibration kinetic energy into the elastic potential energy of the springs, thus achieving vibration buffering and energy absorption in the vertical direction. The stiffness and pre-compression of the springs can be designed and selected according to the target vibration absorption frequency range.

[0042] Adjusting springs 13 are sleeved on guide rods 11 and located between retaining rings 12 and sliders 10. Each guide rod 11 has two sets of adjusting springs 13, which are respectively arranged on both sides of slider 10. In the initial state, slider 10 is located in the middle position of guide rods 11, and the adjusting springs 13 on both sides are in a pre-compressed state. The slider 10 and the retaining rings 12 on both sides maintain a preset initial distance.

[0043] The specific motion process of the hinge-slant linkage mechanism with the second elastic element set on the side is as follows: When the external vibration excitation causes the mass block 1 to sway horizontally, taking the leftward deflection of the mass block 1 as an example, the mass block 1 drives the slant bars 8 on both sides to move through the hinge 9. For the left side mechanism, the slant bar 8 rotates around the hinge 9 on the fixed device 7 and extends inward, pushing the left slider 10 to slide away from the mass block 1 along the guide rod 11 in a direction away from the left slider 1 (i.e., towards the left end of the guide rod 11). As the left slider 10 slides, the distance between the left slider 10 and its left retaining ring 12 decreases, and the adjusting spring 13 located between them is further compressed. After the adjusting spring 13 is compressed, it generates an elastic restoring force opposite to the compression direction. This restoring force is transmitted to the mass block 1 through the slider 10, the hinge 9, and the slant bar 8, forming a rightward driving force component. Meanwhile, in the right-side mechanism, as mass block 1 moves to the left, the right-side inclined rod 8 rotates around the hinge 9 on the right-side fixed device 7 and extends outward, causing the right-side slider 10 to slide along the guide rod 11 towards the mass block 1 (i.e., towards the right end of the guide rod 11). The distance between the right-side slider 10 and its right-side retaining ring 12 decreases, and the right-side adjusting spring 13 is also compressed, generating a restoring force to the left. This restoring force also forms a driving force component to the right. The horizontal components of the restoring forces on both sides are in the same direction, and their superposition effect jointly pushes mass block 1 to return to the right, restoring the hinge inclined rod structure to its original state, thereby offsetting the horizontal vibration impact and achieving lateral vibration suppression. When mass block 1 deflects to the right, the mechanism acts symmetrically, similarly generating a restoring driving force to the left.

[0044] By adjusting the fixed position of the retaining ring 12 on the guide rod 11, the initial distance between the slider 10 and the retaining ring 12 can be changed, which in turn changes the initial pre-compression of the adjusting spring 13. This allows for adjustment of the equivalent horizontal stiffness Kh of the lateral hinge diagonal linkage mechanism, enabling flexible adjustment of the system's vibration absorption frequency range in the horizontal direction. Furthermore, by rationally designing the tilt angle of the diagonal rod 8 (the angle between the diagonal rod 8 and the horizontal direction) and the stiffness of the adjusting spring 13, the equivalent stiffness characteristics of the system in the horizontal direction can also be adjusted.

[0045] The adjusting knob 15 is installed in the threaded holes on the left and right side walls of the housing 6. By rotating the adjusting knob 15, its threaded output end can move forward or backward in the horizontal direction, thereby applying or releasing axial load on the buckling beam 14.

[0046] The adjustment knob 15 and the buckling beam 14 together form an adjustable buckling beam structure, providing a detailed change process for negative stiffness characteristics as follows: In the initial state, the adjustment knob 15 is in the relaxed position, and the buckling beam 14 is in a naturally straightened or slightly pre-bent state. At this time, the lateral stiffness of the buckling beam 14 is positive, providing a positive elastic restoring force to the horizontal movement of the mass block 1, and the system as a whole exhibits pure stiffness characteristics. When it is necessary to reduce the equivalent natural frequency of the system to cope with low-frequency vibrations, the operator rotates the adjustment knob 15, pushing its threaded output end inward, applying an axial compressive load to the buckling beam 14. The two ends of the buckling beam 14 are subjected to opposing compression, and the beam body begins to bend and deform. As the adjustment knob 15 continues to rotate, the axial compressive load on the buckling beam 14 continuously increases. When the axial load approaches the Euler critical buckling load of the buckling beam 14... When E is the elastic modulus of the material, I is the moment of inertia of the section, and L is the effective length of the buckling beam, the buckling beam 14 enters the critical buckling state. On the load-displacement characteristic curve, the tangential stiffness of the buckling beam 14 gradually decreases from a positive value to zero during this stage, and further transforms into a negative value—that is, the buckling beam 14 exhibits negative stiffness characteristics: when the displacement of the mass block 1 from the equilibrium position increases, the lateral restoring force provided by the buckling beam 14 not only does not increase with the increase of displacement, but decreases instead, exhibiting the anomalous mechanical behavior of increasing displacement and decreasing resistance. By finely adjusting the advance of the knob 15, the magnitude of the axial preload on the buckling beam 14 and the degree of bending deformation of the beam can be continuously controlled, thereby continuously adjusting the magnitude of the negative stiffness provided by the buckling beam 14. .

[0047] The negative stiffness buckling beam adjustment mechanism and the positive stiffness springs (upper connecting spring 2, lower connecting spring 3 and adjustment spring 13) are connected in parallel. The equivalent total stiffness of the system near the static equilibrium position can be expressed as:

[0048]

[0049] In the formula, The total normal stiffness provided by the vertical connecting spring and the lateral adjusting spring , Negative stiffness provided for buckling beams near the critical buckling state The axial preload of the buckling beam 14 can be continuously adjusted by rotating the preload adjustment knob 13. The numerical value.

[0050] When negative stiffness absolute value and positive stiffness Achieving matching near the static equilibrium position (i.e.) When ), the equivalent dynamic stiffness of the system It approaches zero. At this point, the system's natural frequency is given by the following equation:

[0051]

[0052] In the formula, The mass of mass block 1, Let be the system's equivalent natural angular frequency. Since... The value can be adjusted to near zero, and the system's natural frequency also approaches zero, thus achieving an extremely low theoretical natural frequency and realizing efficient isolation of low-frequency and even ultra-low-frequency vibrations. Simultaneously, due to the positive stiffness spring... The static stiffness is always present and greater than zero, ensuring that the system retains sufficient static support stiffness when subjected to static loads. It will not lose its load-bearing capacity due to the introduction of negative stiffness, thus achieving high static and low dynamic stiffness characteristics. The horizontal equilibrium position of the mass block 1 can also be finely adjusted by independently adjusting the left and right adjustment knobs 15 to compensate for offsets caused by manufacturing tolerances or asymmetrical loads.

[0053] In this specific embodiment, the outer casing 6 is a rectangular frame structure made of aluminum alloy or steel, providing external protection for the entire vibration absorber and a mounting base for internal components. Mounting holes are provided on the left and right side walls of the outer casing 6 for mounting the fixing device 7 and the adjustment knob 15. The upper base 4 is fixed to the top of the outer casing 6 with bolts, and the lower base 5 is fixed to the bottom of the outer casing 6 with bolts. Both the upper base 4 and the lower base 5 have multiple mounting bolt holes for fixing the entire vibration absorber to the protected equipment or vibration source. The outer casing 6 adopts a closed or semi-closed structure, protecting the internal mass block 1, spring assembly, and hinge diagonal rod mechanism, preventing external debris from entering and affecting the mechanism's movement.

[0054] like Figure 5 As shown, this invention employs a structure based on the parallel connection of positive and negative stiffness. The mass of mass block 1 is M, and the upper connecting spring 2 and the lower connecting spring 3 together provide the vertical positive stiffness. The adjusting spring 13 in the lateral hinge diagonal linkage mechanism provides positive stiffness in the horizontal direction. The buckling beam 14 provides adjustable negative stiffness in the pre-stressed state. ( The equivalent total stiffness of the system near its static equilibrium position. Adjust continuously using the adjustment knobs 15 on both the left and right sides. The size makes It is continuously adjustable near zero, thereby achieving continuous adjustment of the system's equivalent natural frequency and realizing the purpose of low-frequency and ultra-low-frequency vibration isolation.

[0055] Compared to traditional linear vibration absorbers, the multi-directional vibration absorber with negative stiffness adjustment proposed in this invention significantly reduces the peak value in the resonance region, shifts the natural frequency towards lower frequencies, and exhibits superior vibration damping performance across the entire frequency range. Particularly in the low-frequency range, the introduction of negative stiffness drastically reduces the system's equivalent dynamic stiffness, resulting in significantly better low-frequency vibration isolation than traditional linear vibration absorbers. Furthermore, by adjusting knob 15 to change the negative stiffness value of the buckling beam 14, online tuning of the resonance frequency can be achieved to adapt to external excitations of different frequencies.

[0056] The working process of this invention is as follows: The vibration absorber is fixed to the protected equipment or vibration source through the mounting holes on the upper base 4 and the lower base 5. When external vibration is transmitted to the vibration absorber, the mass block 1 moves relative to the outer shell 6 under the action of inertia. In the vertical direction, the upper connecting spring 2 and the lower connecting spring 3 provide elastic restoring force and normal stiffness. The system absorbs and buffers vertical vibrations, converting the kinetic energy of the vibrations into the elastic potential energy of the springs. In the horizontal direction, the lateral hinge-slant linkage mechanism operates: the horizontal swaying of mass block 1 drives the sliders 10 on both sides to slide along the guide rod 11 via hinge 9 and slant rod 8, compressing the adjusting spring 13. The reverse restoring force generated by the adjusting spring 13 is transmitted back to mass block 1 through slider 10, hinge 9, and slant rod 8, forming a restoring driving force opposite to the swaying direction, thus counteracting the lateral vibration impact. Simultaneously, the buckling beam 14, under the axial preload applied by the adjusting knob 15, is in a near-critical buckling working state. Its negative stiffness effect is compensated by the positive stiffness of the upper connecting spring 2, lower connecting spring 3, and adjusting spring 13, significantly reducing the equivalent dynamic stiffness of the system near the equilibrium position, thereby achieving efficient isolation of low-frequency vibrations. By rotating the adjusting knobs 15 on the left and right sides, the preload and negative stiffness of the buckling beams 14 on both sides can be adjusted respectively, thereby adjusting the equivalent natural frequency of the system to adapt to external excitations of different frequencies and directions.

[0057] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0058] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A multi-directional vibration absorber with negative stiffness adjustment function, characterized in that, Includes an outer shell (6), inside which is provided a mass block (1), the top and bottom of the mass block (1) are connected to the inner wall of the outer shell (6) by a first elastic element, the two sides of the mass block (1) are connected to the inner wall of the outer shell (6) by a second elastic element, and a negative stiffness adjustment mechanism is provided between the mass block (1) and the outer shell (6), and the first elastic element connection and the second elastic element connection are configured to be in a compressed state.

2. A multi-directional vibration absorber with negative stiffness adjustment function according to claim 1, characterized in that, The first elastic element includes an upper connecting spring (2) and a lower connecting spring (3). The top wall of the outer shell (6) is fixedly connected to an upper base (4). The upper connecting spring (2) is fixedly installed inside the upper base (4). The other end of the upper connecting spring (2) is fixedly connected to the outer shell (6). The bottom wall of the outer shell (6) is fixedly connected to a lower base (5), one end of the lower connecting spring (3) is fixedly connected inside the lower base (5), and the other end of the lower connecting spring (3) is fixedly connected to the outer shell (6).

3. A multi-directional vibration absorber with negative stiffness adjustment function according to claim 1, characterized in that, The second elastic element includes a guide rod (11), with retaining rings (12) fixedly connected to both ends of the guide rod (11). A slider (10) is symmetrically sleeved on the guide rod (11). A spring-loaded element is provided between the slider (10) and the retaining ring (12). The displacement of the slider (10) is transmitted to the mass block (1) and the outer shell (6).

4. A multi-directional vibration absorber with negative stiffness adjustment function according to claim 3, characterized in that, The rebound element is an adjusting spring (13), which is sleeved on the guide rod (11), and the two ends of the adjusting spring (13) abut against the slider (10) and the retaining ring (12) respectively.

5. A multi-directional vibration absorber with negative stiffness adjustment function according to claim 3, characterized in that, The slider (10) is symmetrically hinged with a diagonal rod (8). The end of the diagonal rod (8) away from the slider (10) is hinged with a fixing device (7) via a hinge (9). One of the fixing devices (7) is fixedly connected to the inner side wall of the outer shell (6), and the other fixing device (7) is fixedly connected to the side wall of the mass block (1).

6. A multi-directional vibration absorber with negative stiffness adjustment function according to claim 1, characterized in that, The negative stiffness adjustment mechanism includes an adjustment knob (15) movably disposed on the outer side wall of the outer shell (6). The adjustment knob (15) is threadedly connected to a buckling beam (14). The buckling beam (14) is fixedly connected to the side wall of the mass block (1). The adjustment knob (15) abuts against the outer side wall of the outer shell (6).

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