Design Of A New High Static Stiffness And Low Dynamic Stiffness Vibration Isolator And Its Application On Car Seat Suspension

Low frequency vibration isolation has always been a problem in engineering applications,and linear vibration isolation systems reduce the natural frequency,which will lead to a decrease in the bearing capacity.A nonlinear isolator with high static stiffness and low dynamic stiffness(HSLDs)can effectively solve this problem.It can obtain near zero dynamic stiffness within a certain displacement range and maintain the static stiffness stabilizes near the predetermined value,effectively reducing the initial frequency of vibration isolation.In this paper,a new type of high static and low dynamic stiffness vibration isolator is designed and its static and dynamic characteristics are analyzed.It is compared with other types of high static and low dynamic stiffness isolators,and its application in vehicle seat suspension vibration reduction is discussed.The main research contents are as follows:(1)A special-shaped cam-roller type high static low dynamic stiffness isolator with a wider low dynamic stiffness displacement curve is designed,and the mechanical model of it is established.From the perspective of statics,the errors of the elastic force and equivalent damping coefficient are analyzed when the mechanical model is approximated.(2)The steady-state responses of nonlinear isolator models under harmonic excitation are obtained using the average method,respectively,and the stability analysis is performed.The influence of structural parameters on the force transmissibility and displacement transmissibility of special-shaped cam-roller type vibration isolator are investigated and vibration isolation performance under shock excitation is also analyzed by Runge-Kutta method.Then,the vibration isolation performance of the new high static low dynamic stiffness isolator and the traditional circular camroller type and multiple sets of spring geometry parallel type high static low dynamic stiffness isolator are compared.Research shows that the new high static low dynamic stiffness isolator has lowest initial frequency of vibration isolation.The initial frequency of vibration isolation under harmonic force excitation can be reduced to 75% of the round cam roller type,and it can be reduced to 40% of the round cam roller type under displacement excitation.(3)A car body-seat-human body coupling model based on high static and low dynamic stiffness isolators is established,and the vibration isolation performance is explored under the harmonic displacement excitation,impact excitation,and random excitation of the road surface.The impact of the new vibration isolator in the coupling model is compared with linear isolators.Research shows that in the coupling model,vibration isolation performance of the new type of vibration isolator is better than that of the linear vibration isolator.