A Negative Stiffness Structure That Provides Stable Negative Stiffness Values

Abstract

The invention discloses a novel negative stiffness structure capable of providing a stable negative stiffness value, and belongs to the technical field of low-frequency vibration isolating. The novelnegative stiffness structure comprises a supporting seat, a base and at least one pair of negative stiffness units. Each negative stiffness unit comprises a connecting rod transmission mechanism, an upper magnet, a middle magnet and a lower magnet, wherein the upper magnet, the middle magnet and the lower magnet are sequentially arranged at intervals from top to bottom in a corresponding mode, andthe middle magnet repels the upper magnet and the lower magnet. Each connecting rod transmission mechanism comprises an upper connecting rod, a middle connecting rod and a lower connecting rod. The top ends of the upper connecting rods are connected with the supporting seat in a hinged mode, and the bottom ends of the upper connecting rods are connected with the middle connecting rods in a hingedmode. The middle connecting rods are fixedly connected with the middle magnets. The top ends of the lower connecting rods are connected with the middle connecting rods in a hinged mode, and the bottom ends of the lower connecting rods are connected with the base in a hinged mode.

Description

technical field [0001] The invention belongs to the technical field of low-frequency vibration isolation, and in particular relates to a negative stiffness structure capable of providing stable negative stiffness values. Background technique [0002] With the rapid development of science and technology, the optical industry, photosensitive chemistry, aerospace and many other fields are developing towards unprecedented high precision, which accordingly puts forward more stringent requirements for the working environment. Vibration has always been an unavoidable unfavorable factor in the process of machining and manufacturing and precision instrument measurement and control. It not only generates noise, but also reduces production accuracy and even shortens product life. In precision and ultra-precision machining and measurement and control, the hazards of low-frequency and ultra-low-frequency vibration are particularly prominent. [0003] In order to eliminate the hazards of...

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Problems solved by technology

[0004] However, there are still some problems in the current common negative stiffness structure, especially the strong nonlinearity of the negative stiffness value, which will change significantly with the displacement stroke of the negative stiffness structure, and it is difficult to maintain stability in the entire working displacement range. If the negative stiffness value is large, the negative stiffness value will even decay sharply, which leads to the inability of the entire structure to maintain a stable and constant property during work, and also limits the application of such a negative stiffness structure in more occasions

In the analysis and calculation, due to its strong nonlinearity, the negative stiffness value can only be regarded as constant or linear when the vibration is small, that is, the working displacement range is small, which greatly increases the complexity of calculation.

[0005] There are many types of existing negative stiffness structures. It can be said that almost all negative stiffness structures have unstable and nonlinear stiffness values. For example, the Chinese patent No. Quasi-zero stiffness vibration isolator", patent number 201710265068.6 (publication number CN106870615A) Chinese patent "a disk-shaped nonlinear low-frequency vibration isolator based on the principle of positive and negative stiffness parallel connection", patent number 201510813154.7 (publication number The Chinese patent CN106763466A) discloses "a new type of positive and negative stiffness parallel low-frequency vibration isolation mechanism", and the negative stiffness structure mentioned and used in other patents

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