Effects of Restriction Characteristics on Characteristics of Air Suspension

Abstract

In this study we make clear the characteristics of an air suspension with a flow channel connected from a cylinder to a reservoir tank. The flow resistance of channel is given by a viscous restriction or an orifice restriction. Differences between approximated analytical results, which are based on the 3-element model, of stiffness and damping coefficients of the air suspension with the viscous restriction and results of numerical analysis considering non-linear characteristics are very small. Moreover, the approximated analytical results of a transfer function of the air suspension and the experimental results of it are good well. Dependence of the oscillating amplitude on the maximum value of the transfer function of the air suspension system with the viscous restriction is very small since dependence of the oscillating amplitude on the stiffness and the damping is almost negligible. However, it depends on the oscillating amplitude of air suspension system with the orifice restriction because the damping coefficient of that decreases when the oscillating amplitude decreases. We can choose the optimal restriction coefficient of viscous restriction to minimize resonance amplitude easily. However, it is difficult to choose the optimal restriction coefficient of orifice restriction to minimize resonance amplitude because the oscillating amplitude often fluctuates generally. Thus, the air suspension with the viscous restriction is better for isolating the small vibration, in case of the high precision machinery.