An improved structure designed for an air spring vibration isolation system and its experiment research

To reduce the stiffness of a vibration isolation system is a fundamental way to improve the ability of low frequency vibration isolation. In this paper, a new structure of an air spring vibration isolation system was proposed. The structure can ensure the static bearing capacity unchanged, but the stiffness is greatly reduced. The new system introduces a universal joint and a connection structure on the basis of the original system. In the static equilibrium state, the universal joint does not rotate, and the new structure will not affect the static bearing capacity of the system. As the bearing platform vibrates, the new structure changes the deformation of the lateral air springs, thus reduces the stiffness of the system. In this paper, a simplified model of the new system was established, and the relationship between the restoring force and displacement was derived. The influence of dimensionless parameters was analyzed. The results show that the vibration isolation frequency of the new system is much lower than that of the original system. The principle prototype was designed and manufactured, and the test was carried out. The experimental results show that the new system can be approximated as a linear system, which is consistent with the theoretical analysis, and the stiffness of the vibration isolation system is reduced by about 75%. The theoretical and experimental results show that the structural design can effectively reduce the stiffness and improve the vibration isolation ability. © 2022, Editorial Office of Journal of Vibration and Shock. All right reserved.