Inertial amplification quasi-zero stiffness vibration isolator

Abstract

The application discloses an inertial amplification quasi-zero stiffness vibration isolator, which comprises a top plate, a bottom plate, an inertial amplification mechanism and a quasi-zero stiffness mechanism; the inertial amplification mechanism comprises a plurality of first unit mechanisms and a plurality of second unit mechanisms, and the first unit mechanisms and the second unit mechanisms are arranged alternately; two adjacent first sliding blocks are connected through a first tension spring, and two adjacent second sliding blocks are connected through a second tension spring; the quasi-zero stiffness mechanism comprises a positive stiffness mechanism and a negative stiffness mechanism, the positive stiffness mechanism is connected with the top plate and the bottom plate at two ends respectively, and all the tension springs and the sliding blocks jointly form the negative stiffness mechanism. In the quasi-zero stiffness vibration isolator, the positive stiffness is provided by compression springs, which can provide the required bearing capacity of the overall mechanism in the vertical direction; the negative stiffness is generated when the tension spring device is stretched and deformed along with the displacement movement of the sliding block; after the negative stiffness and the positive stiffness are connected in parallel, the quasi-zero stiffness effect can be achieved, and then the vibration isolation in the vertical direction of the driver's seat in the high-speed running vehicle in the ultra-low and ultra-wide frequency domain can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration reduction and noise reduction, and in particular to an inertia amplification quasi-zero stiffness vibration isolator. Background Art

[0002] Low-frequency vibration is a prominent problem in the cabs of vehicles used for long-distance transport, especially high-speed trains. Low-frequency vibrations are highly penetrating, have large amplitudes, and are difficult to eliminate. They can cause tinnitus, chest tightness, and even irreversible damage to human organs. Long-term exposure to low-frequency vibrations can easily lead to fatigue and lumbar strain, causing long-term physical and psychological harm. In severe cases, they can pose a safety hazard. Therefore, addressing the low-frequency vibration problem in train cabs requires installing a low-frequency vibration damping and isolation device on the driver's seat.

[0003] When designing a low-frequency seat vibration isolation system for the cab, on the one hand, it is necessary to reduce the resonant frequency of the seat as much as possible, and on the other hand, it is also necessary to reduce the amplitude of the vibration response. Common vibration isolation methods can be divided into active vibration isolation, semi-active vibration isolation and passive vibration isolation according to whether the vibration control system undergoes energy conversion or exchange with the outside world. Active vibration isolation equipment is often complex, too expensive, and has harsh installation conditions. It may also face the problem of low stability. Passive vibration isolation equipment generally has a simple structure, is easy to install, relatively low cost, and easy to maintain. Vibration isolation systems can be divided into linear and nonlinear vibration isolation systems. Linear vibration isolation systems often directly use linear spring damping in parallel, which can effectively control medium and high frequency vibrations, but the starting vibration isolation frequency of the linear vibration isolation system is the natural frequency of the system. However, low-frequency vibrations, especially those below 50 Hz, are poorly suppressed. Nonlinear vibration isolation systems, however, can leverage inherent geometric or material nonlinearities to overcome the incompatibility between linear systems and the requirements for both structural strength and low-frequency vibration isolation. Therefore, to meet the design requirements for lightweight and high-speed trains, simple and reliable nonlinear passive vibration isolation systems are needed to address low-frequency vibrations, improve ride comfort, and protect the safe and stable operation of the vehicle. Recent research has explored two nonlinear mechanisms that achieve low-frequency vibration isolation by increasing the effective mass or reducing the effective height of the system. One is the inertial amplification mechanism, which utilizes the principle of leverage. As the inertial force increases between two points in the structure, it generates anti-resonance. This enhances the system's inertia while effectively offsetting the elastic force, thereby reducing the system's resonant frequency by increasing the effective mass. The other is the quasi-zero stiffness mechanism, which leverages its high static stiffness and low dynamic stiffness to reduce the system's equivalent stiffness without compromising its load capacity, thereby lowering the system's resonant frequency. However, while inertial amplification mechanisms can effectively increase the system's mass, their inherent geometric nonlinearity alone cannot significantly reduce the peak response of the system's nonlinear resonant modes. Furthermore, single quasi-zero stiffness mechanisms also suffer from a narrow quasi-zero range, a single target load, and poor adaptability to variable loads.

[0004] Therefore, there is an urgent need for a vibration isolation device that can combine the advantages of the two mechanisms to reduce the system vibration isolation frequency, effectively reduce the vibration response peak, and at the same time broaden the application range of quasi-zero stiffness to achieve ultra-low and ultra-wide frequency domain vibration isolation. Summary of the Invention

[0005] The object of the present invention is to provide an inertial amplification quasi-zero stiffness vibration isolator to achieve ultra-low and ultra-wide frequency range vibration isolation in the vertical direction of the driver's seat in a high-speed vehicle.

[0006] To achieve the above-mentioned purpose, the present invention provides an inertia-amplifying quasi-zero stiffness vibration isolator, comprising a top plate, a bottom plate, a quasi-zero stiffness mechanism and an inertia-amplifying mechanism; the quasi-zero stiffness mechanism comprises a positive stiffness mechanism and a negative stiffness mechanism, and the upper and lower ends of the positive stiffness mechanism are respectively connected to the top plate and the bottom plate; the inertia-amplifying mechanism comprises a plurality of first unit mechanisms and a plurality of second unit mechanisms arranged in a circle with the positive stiffness mechanism as the center, and the plurality of first unit mechanisms and the plurality of second unit mechanisms are alternately arranged; the first unit mechanism comprises a first slide rail, a first slider, a first connecting rod and a first connecting rod seat, the first slide rail is arranged on the bottom surface of the top plate, the first slider is slidably arranged on the first slide rail, and the The first connecting rod seat is arranged on the top surface of the base plate, and the upper and lower ends of the first connecting rod are respectively hingedly connected to the first slider and the first connecting rod seat; the second unit mechanism includes a second slide rail, a second slider, a second connecting rod and a second connecting rod seat, the second slide rail is arranged on the top surface of the base plate, the second slider is slidably arranged on the second slide rail, the second connecting rod seat is arranged on the bottom surface of the top plate, and the upper and lower ends of the second connecting rod are respectively hingedly connected to the second connecting rod seat and the second slider; two adjacent first sliders are connected by a first tension spring, and two adjacent second sliders are connected by a second tension spring; all first tension springs, second tension springs, first sliders and second sliders together constitute the negative stiffness mechanism.

[0007] Furthermore, the positive stiffness mechanism includes at least one positive stiffness unit, each of the positive stiffness units includes a displacement constraint device, a compression spring and a fixed seat, the displacement constraint device is connected to the top plate, the fixed seat is arranged on the bottom plate, the compression spring is arranged on the fixed seat, and the displacement constraint device is used to constrain the compression and stretching of the compression spring in the vertical direction.

[0008] Furthermore, the displacement constraint device includes a device body and a vertical displacement constraint guide rod, the vertical displacement constraint guide rod is arranged at the bottom of the device body, and the lower end of the vertical displacement constraint guide rod is movable through the fixed seat; the compression spring is sleeved on the vertical displacement constraint guide rod, the upper end of the compression spring is connected to the bottom of the device body, and the lower end of the compression spring is connected to the fixed seat.

[0009] Furthermore, a first slider seat and a second slider seat for connecting to the first connecting rod and the second connecting rod are respectively provided at the bottom of the first slider and the top of the second slider, and a tension spring fixing member is respectively provided on the left and right sides of the first slider seat and the second slider seat.

[0010] Furthermore, the first slider seat and the second slider seat are both provided with a first hinge hole; the first connecting rod seat and the second connecting rod seat are both provided with a second hinge hole.

[0011] Furthermore, both ends of the first connecting rod and the second connecting rod are hinged to the first hinge hole and the second hinge hole respectively through a retaining spring.

[0012] Furthermore, the tension spring fixing member is a bolt; each slider and the slider seat are provided with a threaded hole matching the bolt.

[0013] Furthermore, the first slide rail and the second slide rail adopt linear guide rails, cross ball guide rails, dovetail guide rails or linear bearings.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) In the inertia-amplified quasi-zero stiffness isolator of the present invention, the positive stiffness is provided by the compression spring, which can provide the vertical bearing capacity required by the overall mechanism; the negative stiffness is generated when the tension spring device produces tensile deformation as the slider moves, and the negative stiffness and the positive stiffness are connected in parallel to achieve a quasi-zero stiffness effect; by adjusting the wire diameter and length of the vertical and tension springs, different target bearing capacities and different system static stiffnesses can be achieved.

[0016] (2) In the inertia amplification quasi-zero stiffness vibration isolator of the present invention, the connecting rod, the slider and the slide rail are combined to form an inertia amplification mechanism, which provides a mass amplification effect for the system and can reduce the vibration isolation frequency.

[0017] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0019] Figure 1 A three-dimensional view of an inertial amplification quasi-zero stiffness vibration isolator according to a preferred embodiment of the present invention;

[0020] Figure 2 This is a schematic structural diagram of the components of the inertia amplification quasi-zero stiffness vibration isolator according to a preferred embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the verification of the experimental results of forming quasi-zero stiffness according to the preferred embodiment of the present invention;

[0022] Figure 4 A schematic diagram illustrating the verification of vibration response experimental results of a preferred embodiment of the present invention;

[0023] In the figure: 1-top plate; 2-bottom plate; 3-first unit mechanism; 3.1-first slide rail; 3.2-first slider; 3.21-first slider seat; 3.3-first connecting rod; 3.4-first connecting rod seat; 3.5-first tension spring; 4-second unit mechanism; 4.1-second slide rail; 4.2-second slider; 4.3-second connecting rod; 4.4-second connecting rod seat; 4.5-second tension spring; 5-positive stiffness unit; 5.1-displacement constraint device; 5.2-compression spring; 5.3-fixed seat. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in this field based on these embodiments are all within the scope of protection of the present invention.

[0025] See also Figure 1 and Figure 2 The present invention provides an inertia-amplifying, quasi-zero-stiffness vibration isolator for use in a low-frequency vibration isolation device for a driver's seat. The isolator comprises a top plate 1, a bottom plate 2, an inertia-amplifying mechanism, and a quasi-zero-stiffness mechanism. The top and bottom plates are arranged parallel to each other, with the inertia-amplifying and quasi-zero-stiffness mechanisms disposed between them. The specific structure is as follows:

[0026] The inertia amplification mechanism includes a plurality of first unit mechanisms 3 and a plurality of second unit mechanisms 4 arranged in a circle, and the plurality of first unit mechanisms 3 and the plurality of second unit mechanisms 4 are arranged alternately; the first unit mechanism 3 includes a first slide rail 3.1, a first slider 3.2, a first connecting rod 3.3 and a first connecting rod seat 3.4, the first slide rail 3.1 is fixedly arranged on the bottom surface of the top plate 1, the first slider 3.2 is slidably arranged on the first slide rail 3.1, the first connecting rod seat 3.4 is fixedly arranged on the top surface of the bottom plate 2, and the upper and lower ends of the first connecting rod 3.2 are respectively hingedly connected to the first slider 3.2 and the first connecting rod seat 3.4. The second unit mechanism 4 includes a second slide rail 4.1, a second slider 4.2, a second connecting rod 4.3, and a second connecting rod seat 4.4. The second slide rail 4.1 is mounted on the top surface of the base plate 2. The second slider 4.2 is slidably mounted on the second slide rail 3.1. The second connecting rod seat 4.4 is fixedly mounted on the bottom surface of the top plate 1. The second connecting rod 4.3 is hingedly connected to the second connecting rod seat 4.4 and the second slider 4.2 at its upper and lower ends. In this structural arrangement, the first unit mechanism 3 and the second unit mechanism 4 have the same specific structure; the first connecting rod 3.3 and the second connecting rod 4.3 are both rigid connecting rods. Two adjacent first sliders 3.1 are connected by a first tension spring 3.5, and two adjacent second sliders 4.1 are connected by a second tension spring 4.5. Using the slide rails as a reference for description, multiple first unit mechanisms 3 are equidistantly arranged on the top plate 1, and multiple second unit mechanisms 4 are equidistantly arranged on the base plate 2. The first unit mechanisms are alternately arranged between two adjacent second unit mechanisms 4. It should be further explained that, in this structural arrangement, the slider slides back and forth on the slide rail along its extension direction but does not disengage.

[0027] The quasi-zero stiffness mechanism includes a positive stiffness mechanism and a negative stiffness mechanism. The two ends of the positive stiffness mechanism are respectively connected to the top plate 1 and the bottom plate 2. The positive stiffness mechanism has at least one positive stiffness unit 5, which includes a displacement constraint device 5.1, a compression spring 5.2 and a fixed seat 5.3. The displacement constraint device 5.1 is connected to the top plate 1, and the fixed seat 5.3 is set on the bottom plate 2. The compression spring 5.2 is located between the displacement constraint device 5.1 and the fixed seat 5.3. The displacement constraint device is used to constrain the compression and extension of the compression spring in the vertical direction. The sliders are connected by tension springs to form a negative stiffness mechanism, that is, all the first tension springs 3.5, the second tension springs 4.5, the first slider 3.2 and the second slider 4.2 together constitute a negative stiffness mechanism to compensate for the positive stiffness provided by the vertical compression spring 5.2 to form a quasi-zero stiffness. Among them, the vertical direction is the direction perpendicular to the top plate 1 and the bottom plate 2. Preferably, the positive stiffness mechanism includes three positive stiffness units 5, which are arranged in a triangular shape, and the vertical perpendicular to the center of gravity of the triangle coincides with the centerline of the circular structure formed by the plurality of first units 3 and the plurality of second units 4. That is, the vertical centerline of the positive stiffness mechanism coincides with the vertical centerline of the inertia amplification mechanism. Specifically, the displacement constraint device 5.1 includes a device body with a bearing and a vertical displacement constraint guide rod; the vertical displacement constraint guide rod is arranged at the bottom of the device body, and the lower end of the vertical displacement constraint guide rod movably passes through the fixed seat 5.3. A compression spring 5.2 is mounted on the vertical displacement constraint guide rod, the upper end of the compression spring is connected to the bottom of the device body, and the lower end of the compression spring is connected to the fixed seat. In this structural arrangement, one end of the compression spring 5.2 is fixed to the bottom plate 2 of the vibration isolator through the fixed seat 5.3, and the other end is fixed to the top plate 1 of the vibration isolator through the vertical displacement constraint guide rod. When the vibration isolator is compressed, the compression spring 5.2 deforms to provide positive stiffness for the vibration isolation system.

[0028] In one specific embodiment, the bottom of the first slider 3.2 and the top of the second slider 4.2 are respectively provided with a first slider seat 3.21 and a second slider seat for connecting to the first connecting rod 3.3 and the second connecting rod 4.3. A tension spring fixing member is provided on each left and right side of the first slider seat and the second slider seat; preferably, the tension spring fixing member is a bolt. Each slider and slider seat is provided with a threaded hole that matches the bolt. The tension spring fixing members provided on the first slider seat and the second slider seat are used to fix the first tension spring 3.5 and the second tension spring 4.5, respectively. Furthermore, the first slider seat and the second slider seat are each provided with a first hinge hole, and the first connecting rod seat and the second connecting rod seat are each provided with a second hinge hole. The ends of the first and second connecting rods are respectively hinged to the first and second hinge holes of the slider seat and the connecting rod seat via retaining springs. Specifically, the slider seat is fixed to the bottom or top of the corresponding slider, and the fixing seat 5.3 is fixed to the top plate 1 and the bottom plate 2. In this structural arrangement, the slider and the guide rail are both arranged horizontally, and the horizontal slider moves linearly along the rail. The rigid connecting rod, slider, and rail combine to form an inertia amplification mechanism, providing a mass amplification effect for the vibration isolation system. Adjacent first and second sliders are connected by corresponding first and second tension springs, respectively. Adjacent rails are arranged in a fan-shaped pattern (i.e., the aforementioned multiple first unit mechanisms 3 and multiple second unit mechanisms 4 are arranged in a circular pattern). Under load, the isolator's tension springs deform as the sliders move, providing negative stiffness for the isolation system and achieving quasi-zero stiffness overall.

[0029] In a specific embodiment, the first and second slide rails 3.1 and 4.1 can be linear guides, cross-ball guides, dovetail guides, or linear bearings. Depending on the specific situation, the load capacity can be adjusted by increasing or decreasing the diameter and number of compression and tension springs. In addition to the aforementioned negative stiffness mechanisms, magnetic elements, folding beams, and other alternatives can also be used to provide negative stiffness.

[0030] Example 1

[0031] In this embodiment, when a load is applied to the top plate 1 of the vibration isolator After that, the compression spring 5.2 in the positive stiffness mechanism undergoes a certain amount of deformation displacement. , according to the stiffness of compression spring 5.2 The elastic force of the compression spring in the vertical direction can be calculated as The angle between each rigid link and the corresponding slide rail is determined by the initial angle becomes , the displacement of each slider along the corresponding slide rail is Since 6 rails (slide rails) are evenly arranged on the top and bottom plates, the deformation of each tension spring is also From an energy point of view, static load The work done is converted into the potential energy of the spring. According to the static equilibrium condition, the stiffness of the tension spring is , it can be calculated that the reaction force provided by the tension spring device in the vertical direction is Displacement and Both are connecting rod angles function, 、 Substitute it into , get the spring reaction force About the connecting rod angle The expression is Therefore, the vertical restoring force of the inertia amplified quasi-zero stiffness vibration isolator of the present invention is .

[0032] To fully demonstrate the quasi-zero stiffness characteristics and vibration isolation performance of the aforementioned vibration isolator, the inventors prepared experimental samples and conducted static tests using a universal test bench and frequency sweep tests using a vibration table. In this embodiment, the isolator's main structural metal components (top plate, bottom plate, connecting rod, and connecting slider seat, etc.) are all made of 6061 aluminum. The slide rail and slider assembly utilizes Hiwin EGW15SA model slide rails. The rigid connecting rod is hinged to the connector via a retaining spring, and all other required fixed locations are bolted. In this experiment, to facilitate observation of the effect and reduce damping, the main mass of the structure was fixed to the slide rail, which can move freely in only one direction.

[0033] By using different spring configurations, the vibration isolator can achieve different target load-bearing capacities. The experiment considers an adult weight of 50-60kg, the weight of the seat is 23kg, and the weight of the vibration isolator is 8.9kg. The static load test result curve of the embodiment of the present invention using a compression spring with a wire diameter of 2.5×32×70mm and a tension spring with a wire diameter of 1.5×12×30mm is shown in Figure 3 . Figure 3 The quasi-zero stiffness characteristic of the static displacement curve shown is significant, and the target load-bearing capacity of 830N is close to the total weight of the human body, driver's seat and vibration isolator.

[0034] When conducting field tests at the experimental site, the signal generator first emits signals of different frequency bands and amplitudes. The signal is amplified by the power amplifier, and then the vibration table transmits the simple harmonic vibration to the bottom of the vibration isolator. Acceleration sensors are installed on the bottom and top plates of the vibration isolator to detect the vibration conditions of each component and calculate the final transfer function. Figure 4 The final experimental results are shown in Figure 2. As can be seen, compared to an ordinary driver's seat without the vibration isolator in this example, this experimental result shows coordinated attenuation of low, medium, and high frequencies. The cutoff frequency is 4.18 Hz, which is much lower than that of an ordinary seat, a decrease of 87.13%, significantly improving the low-frequency vibration reduction effect of the driver's seat.

[0035] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An inertial amplification quasi-zero stiffness vibration isolator, characterized in that: The cam is connected to the top plate of the vehicle frame, and the cam is connected to the top plate of the vehicle frame by the support leg. The cam is connected to the top plate of the vehicle frame by the support leg. The cam is connected to the top plate of the vehicle frame by the support leg. The cam is connected to the bottom surface of the sliding plate, and the second sliding block is slidingly arranged on the second sliding rail. The second connecting rod seat is arranged on the bottom surface of the top plate, and the upper and lower ends of the second connecting rod are respectively hingedly connected to the second connecting rod seat and the second sliding block; the two adjacent first sliding blocks are connected by a first tension spring, and the two adjacent second sliding blocks are connected by a second tension spring; the bottom of the first sliding block and the top of the second sliding block are respectively provided with a first sliding block seat and a second sliding block seat for connecting with the first connecting rod and the second connecting rod, and a tension spring fixing part is provided on each side of the left and right sides of the first sliding block seat and the second sliding block; all the first tension springs, the second tension springs, the first sliding block and the second sliding block together constitute the negative stiffness mechanism, which compensates for the positive stiffness provided by the positive stiffness mechanism to form a quasi-zero stiffness; the first connecting rod and the second connecting rod are both rigid connecting rods, and the rigid connecting rod is combined with the sliding block and the sliding rail to form an inertia amplification mechanism to provide a mass amplification effect for the vibration isolation system.

2. The vibration isolator according to claim 1, characterized in that The positive stiffness mechanism includes at least one positive stiffness unit, each of which includes a displacement constraint device, a compression spring and a fixed seat. The displacement constraint device is connected to the top plate, the fixed seat is arranged on the bottom plate, and the compression spring is arranged on the fixed seat. The displacement constraint device is used to constrain the compression and extension of the compression spring in the vertical direction.

3. The vibration isolator according to claim 2, characterized in that The displacement constraint device includes a device body and a vertical displacement constraint guide rod. The vertical displacement constraint guide rod is arranged at the bottom of the device body, and the lower end of the vertical displacement constraint guide rod is movable through the fixed seat. The compression spring is sleeved on the vertical displacement constraint guide rod, the upper end of the compression spring is connected to the bottom of the device body, and the lower end of the compression spring is connected to the fixed seat.

4. The vibration isolator according to claim 1, wherein: The first slider seat and the second slider seat are both provided with a first hinge hole; the first connecting rod seat and the second connecting rod seat are both provided with a second hinge hole.

5. The vibration isolator according to claim 4, characterized in that Both ends of the first connecting rod and the second connecting rod are hinged to the first hinge hole and the second hinge hole respectively through a clamping spring.

6. The vibration isolator according to claim 1, wherein: The tension spring fixing member is a bolt; each slider and the slider seat are provided with a threaded hole matching the bolt.

7. The vibration isolator according to claim 1, wherein: The first slide rail and the second slide rail are linear guide rails, cross ball guide rails, dovetail guide rails or linear bearings.

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