Abstract: For analyzing the effects of the fitting clearance in the balancing axle of multiaxis heavy truck on vehicle dynamics, taking a threeaxle heavy truck as an example, and a nonlinear kinematical model for balancing axle assembly with fitting clearances and a nonlinear vehicle kinetics model are established. With the real road excitations on three wheels as inputs, the dynamic characteristics of vehicle body pitching and the vertical displacements of vehicle body and driver are emphatically studied. By a simulation with Matlab, the dynamic characteristics curves under the excitation of Dgrade road are obtained, which are then compared with those based on ideal model. The results show that the fitting clearances in balancing axle will intensify the vibration of vehicle body.

Key words: multiaxis heavy truck, dynamics, balancing axle assembly, fitting clearance