A line spectrum vibration elimination device and method based on dynamic anti-resonance

Abstract

The present invention proposes a line spectrum vibration cancellation device and method based on dynamic anti-resonance, comprising a main mass block, a positive stiffness spring, a base, an inertial element and a self-adjusting element. The upper and lower ends of the positive stiffness spring are respectively fixed between the main mass block and the base. The inertial element comprises a lever and an inertial mass block. The lever is movably clamped and positioned by a flexible hinge mechanism fixed to the main mass block and the base. The inertial mass block is fixed to one end of the lever and connected to the base via a negative stiffness mechanism. The self-adjusting element is fixed to the base and has two fulcrums at the top that contact the lever respectively. The horizontal resultant force acting on the lever drives the lever to move laterally for self-adjustment. The present invention can adjust the lever ratio of the vibration cancellation device in real time according to the excitation frequency, thereby achieving automatic adjustment of the vibration isolation frequency and enhancing the vibration isolation effect while reducing the weight.

Description

Technical Field

[0001] The present application relates to the technical field of vibration reduction and isolation design, and in particular to a line spectrum vibration reduction device and method based on dynamic anti-resonance. Background Art

[0002] To reduce underwater radiated noise caused by mechanical equipment vibration, various vibration isolation technologies are employed. Double-layer and floating raft isolation, for example, have played a significant role in controlling vibration noise. However, the intermediate mass of double-layer isolation devices and the rafts of floating rafts are both multimodal elastic bodies, which can affect isolation performance and often yield unsatisfactory results. Due to the inherent elasticity of the raft, classic floating raft isolation technology cannot effectively isolate linear vibrations, and radiated noise always contains some linear components.

[0003] The vibration isolator formed based on dynamic anti-resonance vibration isolation technology is a new type of vibration isolator that cleverly combines vibration isolation and vibration absorption. A simple dynamic anti-resonance vibration isolation system is composed of an inertial element (composed of a rigid rod and a counterweight) in addition to the conventional equipment of springs and dampers. Under the excitation of mechanical equipment, the inertial element reciprocates up and down to generate an inertial force. The magnitude is related to the concentrated mass at the end and the amplification ratio of the lever. If the parameters are selected reasonably, when the frequency of the exciting force is equal to the anti-resonance frequency of the system, the transmission of the exciting force to the foundation can be completely offset. Therefore, in the absence of damping, a vibration isolation effect with a zero transmission rate can be achieved, and in the presence of damping, the transmission rate is also very small. The dynamic anti-resonance system has a vibration isolation efficiency of over 90% near the anti-resonance frequency point. At the same time, it overcomes the shortcomings of traditional vibration isolators such as large static deformation and low stiffness. The vibration isolation efficiency is much higher than that of conventional vibration isolation devices. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a line spectrum vibration cancellation device and method based on dynamic anti-resonance in response to the above-mentioned problems. The introduction of a self-adjusting mechanism (elastic fin-type actuator) can adjust the lever ratio of the vibration isolator in real time according to the excitation frequency, so as to achieve the purpose of coinciding the vibration isolation frequency with the excitation frequency, thereby realizing automatic adjustment of the vibration isolation frequency.

[0005] The embodiment of the present application is implemented as follows:

[0006] An embodiment of the present application provides a line spectrum vibration cancellation device based on dynamic anti-resonance, which is characterized in that it includes a main mass block, a positive stiffness spring, a base, an inertial element and a self-adjusting element. The upper and lower ends of the positive stiffness spring are respectively fixed between the main mass block and the base. The inertial element includes a lever and an inertial mass block. The lever is movably clamped and positioned by a flexible hinge mechanism fixed to the main mass block and the base. The inertial mass block is fixed to one end of the lever and connected to the base through a negative stiffness mechanism. The self-adjusting element is fixed to the base, and two fulcrums are provided at the top that are respectively in contact with the lever. The horizontal combined force acting on the lever drives the lever to move laterally for self-adjustment.

[0007] In some optional embodiments, linear bearings are laid on the base, and the self-adjusting element and the negative stiffness mechanism are respectively moved along the linear bearings via sliders.

[0008] In some optional embodiments, the self-adjusting element is an elastic fin-type actuator, including a V-shaped block, an inertia block, a leaf spring and a connecting block. The left and right ends of the V-shaped block are fixed upward to one end of the inertia block, and the other end of the inertia block is connected to one end of the connecting block through a leaf spring. The leaf springs are multiple and symmetrically connected in the upper and lower directions. The other end of the connecting block is connected to the slider, and rubber pads are embedded in the left and right ends of the V-shaped block.

[0009] In some optional embodiments, the flexible hinge mechanism includes an intermediate ball bearing and an intermediate hinge support, and two side ball bearings and two side hinge supports, the two side hinge supports are concave seat structures, the intermediate hinge support corresponds to the inner groove setting of the two side hinge supports, and is connected by a pre-stressed connector, the vertical height of the intermediate ball bearing is greater than the vertical height of the two side ball bearings, and the lever is passed through the gap between the intermediate ball bearing and the two side ball bearings to clamp and position them.

[0010] In some optional embodiments, the pre-stressed connecting part includes a pre-stressed bolt, a pre-stressed nut and a pre-stressed coil spring. The middle hinge support and the hinge supports on both sides are symmetrically provided with an upper fixed block and a lower fixed block. The pre-stressed bolt passes through the lower fixed block and the upper fixed block in sequence. The pre-stressed coil spring is sleeved on the pre-stressed bolt, and the pre-stressed nut is screwed to the pre-stressed bolt to compress the pre-stressed coil spring.

[0011] In some optional embodiments, the two sides of the hinge supports are connected to the connecting base provided below through lateral leaf springs, and the intersection of the extension of the lateral leaf springs coincides with the center position formed by the middle ball bearing and the ball bearings on both sides.

[0012] In some optional embodiments, a limit block is provided at the outer end of the linear bearing.

[0013] In some optional embodiments, the positive stiffness spring is a semicircular corrugated periodic beam structure, which is symmetrically arranged between the main mass block and the base.

[0014] In some optional embodiments, the negative stiffness mechanism includes a negative stiffness bracket and pairs of springs or disc springs or electromagnets or bistable beams symmetrically arranged on the negative stiffness bracket, and the two ends of the inertia block are respectively connected to the pairs of springs or disc springs or electromagnets or bistable beams.

[0015] A method for using a line spectrum vibration cancellation device based on dynamic anti-resonance, characterized by comprising the following contents:

[0016] When the excitation frequency of the elastic fin-type actuator changes, the lever is subjected to unbalanced force and rotates at a small angle around the instantaneous rotation center. The rubber pads at the left and right ends of the V-shaped block deform differently, resulting in unequal forces generated by the vibration of the rubber pads on both sides. The horizontal resultant force acting on the lever is not zero, and the lever will move in the direction of the resultant force until the resultant force on the lever is zero. The lever stops moving and the lever ratio remains unchanged. At this time, the instantaneous center of the lever coincides with the center of the flexible hinge mechanism fixed on the main mass block, and the vibration isolation frequency matches the excitation frequency, realizing automatic adjustment of the vibration isolation frequency. At the same time, the lever enables the inertial mass to achieve inertia amplification, and enhances the vibration isolation effect through the negative stiffness mechanism.

[0017] The beneficial effects of the present application are: 1. The present application provides a line spectrum vibration cancellation device and method based on dynamic anti-resonance. By introducing a self-adjusting element (elastic fin-type actuator), the lever ratio of the vibration cancellation device can be adjusted in real time according to the excitation frequency, so as to achieve the purpose of coinciding the vibration isolation frequency with the excitation frequency, thereby realizing automatic adjustment of the vibration isolation frequency; 2. The introduction of the lever enables the vibration isolation device to achieve inertia amplification of the inertial mass. On this basis, a negative stiffness device is introduced to enhance the vibration isolation effect while reducing the weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 is a cross-sectional view of an anti-resonance vibration elimination device according to an embodiment of the present application;

[0020] Figure 2 This is a schematic diagram of the anti-resonance vibration elimination device according to an embodiment of the present application;

[0021] Figure 3 The force transmission characteristic curve and the mechanical system vibration excitation characteristic diagram of the embodiment of the present application;

[0022] Figure 4 Schematic diagram of the structure of the elastic fin type actuator according to an embodiment of the present application;

[0023] Figure 5 This is a schematic structural diagram of a flexible hinge mechanism according to an embodiment of the present application;

[0024] Figure 6 Schematic diagram of a negative stiffness mechanism according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0028] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended only to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0030] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0031] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0032] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0033] like Figure 1 As shown, based on this, the present invention proposes a line spectrum vibration cancellation device based on dynamic anti-resonance, including a main mass block 1, a positive stiffness spring 2, a base 3, an inertial element and a self-adjusting element 4. The upper and lower ends of the positive stiffness spring are respectively fixed between the main mass block and the base. The inertial element includes a lever 5 and an inertial mass block 6. The lever is movably clamped and positioned by a flexible hinge mechanism 7 fixed on the main mass block and the base. The inertial mass block is fixed to one end of the lever and connected to the base through a negative stiffness mechanism 8. The self-adjusting element is fixed on the base, and two fulcrums are provided on the top end to contact the lever respectively. The horizontal resultant force acting on the lever drives the lever to move laterally for self-adjustment.

[0034] For low-frequency vibrations, traditional passive control methods have the problem of a large mass ratio. The dynamic anti-resonance structure can use a smaller mass to suppress low-frequency vibrations by introducing levers and negative stiffness structures. The vibration isolation frequency of the traditional inertial device cannot be changed once it is determined and the bandwidth is narrow. The introduction of self-adjusting elements can adjust the lever ratio of the vibration elimination device in real time according to the excitation frequency, so as to achieve the purpose of coinciding the vibration isolation frequency with the excitation frequency, thereby realizing automatic adjustment of the vibration isolation frequency.

[0035] A linear bearing 9 is laid on the base, and the self-adjusting element and the negative stiffness mechanism move along the linear bearing through a slider 10. A limit block 11 is provided on the outer end of the linear bearing to prevent the slider from sliding off the linear bearing during the movement of the lever.

[0036] In order to illustrate the working principle of the vibration isolator based on the principle of dynamic anti-resonance, the structure is simplified as follows Figure 2 The dynamic anti-resonance structure shown is composed of Figure 2 It can be seen that the vibration isolator mainly includes: main mass block M, main stiffness k, lever with length L1, and length L2 between two hinges. Among them, the gravity generated by M represents the static load carried by each vibration isolation device under actual working conditions, k represents the dynamic stiffness of the vibration isolation device at each machine foot, x, y, z represent the main mass block, base, inertial mass m respectively. is displacement, further assuming that the lever is a lightweight and rigid rod, and the vibration is a small amplitude vibration, the relationship between the three displacements can be obtained as z = αx + (1-α) y, where α is the lever ratio, From vibration theory, it can be known that the displacement transmission rate at this time is the same as the force transmission rate of the reaction force on the base obtained by the excitation force acting on the main mass block.

[0037] The dynamic equation of the vibration isolator can be obtained by using the Lagrange equation as shown below:

[0038]

[0039] Where: μ is the mass ratio of the vibration damping device,

[0040] ω0 is the natural frequency of the main mass block,

[0041] From the above formula, the force transmission rate of the vibration damping device can be obtained as follows:

[0042]

[0043] The force transmission rate and the vibration excitation of the mechanical system vary with frequency. Figure 3 As shown, it can be seen that when the peak frequency of the excitation force of the mechanical system is the same as the dynamic anti-resonance frequency of the mechanical system, the transmission of the mechanical system vibration to the base can be controlled.

[0044] Example 1

[0045] like Figure 4 As shown, in this embodiment, the self-adjusting element is an elastic fin-type actuator, which includes a V-shaped block 41, an inertia block 42, a leaf spring 43 and a connecting block 44. The left and right ends of the V-shaped block are fixed to one end of the inertia block with their ends facing upwards, and the other end of the inertia block is connected to one end of the connecting block via a leaf spring. There are multiple leaf springs, which are symmetrically connected in the upper and lower parts. The other end of the connecting block is connected to the slider. Rubber pads 45 are respectively embedded in the left and right ends of the V-shaped block.

[0046] When the excitation frequency of an elastic fin actuator changes, if the forces generated by the two rubber pads due to vibration are unequal, the net force acting on the lever will not be zero, and the lever will move in the direction of the net force. The lever will stop moving until the net force on the lever reaches zero, and the lever ratio remains unchanged.

[0047] The V-block is bolted to the inertia block to minimize movement of the V-block due to the force applied by the rubber pad. To counteract residual movement, the inertia block is connected to the connection block using four parallel leaf springs.

[0048] The slider can be locked and fixed in any position. The connecting block of the elastic fin-type actuator secures the elastic fin-type actuator to the linear bearing via the slider. This slider is primarily used to adjust the actuator's axial displacement so that the actuator's two rubber pads are symmetrically positioned directly below the flexible hinge mechanism of the main mass. In the initial state, the rubber pads contact the lever with a slight compressive force.

[0049] Example 2

[0050] like Figure 5 As shown, in this embodiment, the flexible hinge mechanism includes a central ball bearing 71 and a central hinge support 72, as well as two side ball bearings 73 and two side hinge supports 74. The two side hinge supports are concave-shaped seat structures. The central hinge support is arranged corresponding to the inner grooves of the two side hinge supports and is connected by a preload connector 75. The vertical height of the central ball bearing is greater than that of the two side ball bearings. The lever is inserted into the gap between the central ball bearing and the two side ball bearings to clamp and position it. Slide grooves are machined on both the upper and lower surfaces of the lever, allowing it to slide freely along its own axis.

[0051] In this embodiment, the preload connector includes a preload bolt 751, a preload nut 752, and a preload coil spring 753. Upper and lower fixing blocks 754 and 755 are symmetrically positioned on the center hinge support and the hinge supports on either side. The preload bolt passes through the lower and upper fixing blocks, respectively. The preload coil spring is sleeved over the preload bolt, and the preload nut is threadedly engaged with the preload bolt to compress the preload coil spring. The preload connector applies a slight preload force to the lever, preventing it from drifting during self-adjustment and reducing noise generated during vibration.

[0052] The two sides of the hinge supports are connected to the connecting base 757 provided below through the lateral leaf springs 756. The intersection of the extension of the lateral leaf springs coincides with the center position formed by the middle ball bearing and the ball bearings on both sides, ensuring that the lever can rotate around the instantaneous center of the flexible hinge mechanism.

[0053] In some optional embodiments, the positive stiffness spring is a semicircular corrugated periodic beam structure and is symmetrically arranged between the main mass block and the base.

[0054] Negative stiffness mechanisms can be implemented in various forms, such as double springs, disc springs, electromagnets, bistable beams, etc. Regardless of the method used, they only need to be placed between the inertial mass block and the linear bearing.

[0055] Example 3

[0056] like Figure 6 As shown, in this embodiment, the negative stiffness mechanism includes a negative stiffness bracket 81 and springs 82 symmetrically arranged on the negative stiffness bracket in pairs, and both ends of the inertia block are respectively connected to the paired springs.

[0057] On the basis of a lever structure amplifying the inertial force generated by the inertial mass, a negative stiffness mechanism is introduced. The force generated by the negative stiffness is in phase with the inertial mass, further increasing the equivalent mass of the coupling system. Compared with the general positive stiffness mechanism, a smaller inertial mass can be used to generate a larger inertial force.

Claims

1. A line spectrum vibration elimination device based on dynamic anti-resonance, characterized in that: The invention comprises a main mass block, a positive stiffness spring, a base, an inertial element and a self-adjusting element. The upper and lower ends of the positive stiffness spring are respectively fixed between the main mass block and the base. The inertial element comprises a lever and an inertial mass block. The lever is movably clamped and positioned by a flexible hinge mechanism fixed to the main mass block and the base. The inertial mass block is fixed to one end of the lever and connected to the base through a negative stiffness mechanism. The self-adjusting element is fixed to the base and has two fulcrums at the top that are in contact with the lever respectively. The horizontal resultant force acting on the lever drives the lever to move laterally for self-adjustment.

2. The line spectrum vibration elimination device based on dynamic anti-resonance according to claim 1, characterized in that: A linear bearing is laid on the base, and the self-adjusting element and the negative stiffness mechanism move along the linear bearing via sliders respectively.

3. The line spectrum vibration elimination device based on dynamic anti-resonance according to claim 2, characterized in that: The self-adjusting element is an elastic fin-type actuator, which includes a V-shaped block, an inertia block, a leaf spring and a connecting block. The left and right ends of the V-shaped block are fixed upward to one end of the inertia block, and the other end of the inertia block is connected to one end of the connecting block through a leaf spring. There are multiple leaf springs, which are symmetrically connected in the upper and lower parts. The other end of the connecting block is connected to the slider. Rubber pads are embedded in the left and right ends of the V-shaped block.

4. A line spectrum vibration cancellation device based on dynamic anti-resonance according to claim 2 or 3, characterized in that: The flexible hinge mechanism includes an intermediate ball bearing and an intermediate hinge support, and ball bearings on both sides and hinge supports on both sides. The hinge supports on both sides are concave seat structures. The intermediate hinge support is arranged corresponding to the inner grooves of the hinge supports on both sides and is connected by a pre-stressed connector. The vertical height of the intermediate ball bearing is greater than the vertical height of the ball bearings on both sides. The lever is inserted into the gap between the intermediate ball bearing and the ball bearings on both sides to clamp and position them.

5. The line spectrum vibration elimination device based on dynamic anti-resonance according to claim 4, characterized in that: The pre-stressed connecting part includes a pre-stressed bolt, a pre-stressed nut and a pre-stressed coil spring. The middle hinge support and the hinge supports on both sides are symmetrically provided with an upper fixed block and a lower fixed block. The pre-stressed bolt passes through the lower fixed block and the upper fixed block in sequence. The pre-stressed coil spring is sleeved on the pre-stressed bolt. The pre-stressed nut is screwed to the pre-stressed bolt to compress the pre-stressed coil spring.

6. The line spectrum vibration elimination device based on dynamic anti-resonance according to claim 5, characterized in that: The two sides of the hinge supports are connected to the connecting base provided below through lateral leaf springs, and the intersection of the extension of the lateral leaf springs coincides with the center position formed by the middle ball bearing and the ball bearings on both sides.

7. The line spectrum vibration elimination device based on dynamic anti-resonance according to claim 6, characterized in that: The outer end of the linear bearing is provided with a limit block.

8. A line spectrum vibration cancellation device based on dynamic anti-resonance according to claim 6 or 7, characterized in that: The positive stiffness spring is a semicircular corrugated periodic beam structure and is symmetrically arranged between the main mass block and the base.

9. The line spectrum vibration elimination device based on dynamic anti-resonance according to claim 8, characterized in that: The negative stiffness mechanism includes a negative stiffness bracket and pairs of springs or electromagnets or bistable beams symmetrically arranged on the negative stiffness bracket, and both ends of the inertial mass block are respectively connected to the pairs of springs or electromagnets or bistable beams.

10. A method for using the line spectrum vibration cancellation device based on dynamic anti-resonance according to claim 7 or 9, characterized in that: The invention includes the following contents: when the excitation frequency of the elastic fin-type actuator changes, the lever is subjected to unbalanced force and rotates at a small angle around the instantaneous rotation center. The rubber pads at the left and right ends of the V-shaped block deform differently, resulting in unequal forces generated by the rubber pads on both sides due to vibration. The horizontal resultant force acting on the lever is not zero, and the lever will move in the direction of the resultant force until the resultant force on the lever is zero. The lever stops moving and the lever ratio remains unchanged. At this time, the instantaneous center of the lever coincides with the center of the flexible hinge mechanism fixed on the main mass block, and the vibration isolation frequency matches the excitation frequency, thereby realizing automatic adjustment of the vibration isolation frequency. At the same time, the lever enables the inertial mass to achieve inertia amplification, and enhances the vibration isolation effect through the negative stiffness mechanism.

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