As a superior vibration isolator, air springs have great advantages of variable stiffness and adjustable height in the vertical direction, and are widely used in vehicle chassis suspensions and seat suspensions. Due to the manufacture and assembly deviations, or under certain extreme conditions, air springs are also subject to lateral loads, torsion moments, and turning moments, and produce corresponding deformations. This paper is focused on the stiffness characteristics of the air spring in the vertical, lateral, torsional and pitching directions, as well as their coupling effects. A fluid-structure coupling model is established using the FEA(finite element analysis) software ABAQUS. The accuracy of the FEA model is verified by the bench test. It is found that the lateral stiffness, torsional stiffness and pitching stiffness of the air spring are strongly influenced by the preload; severe lateral instability would be caused by little derivation of pitching angle during the pre-installation; increasing the cord angle of bellow will enlarge the pitching stiffness, and improve the anti-rolling ability of the air suspension.
 

Air springs, Lateral stiffness, Torsional stiffness, Pitching stiffness, Coupling effects