Investigation On Dynamics For Spur Planetary Gear Auxiliary Transmission Affiliated To A Heavy-duty Truck Transmission

The heavy-duty truck transmission with planetary gear structure is used on theautomobile due to its compact structure, light weight, large speed ratio as well as highefficiency and steady. The study of dynamics for the planetary gear structure has beenperformed to obtain the inherent characteristics and analysis the influence on the naturalfrequencies by the mass of the parts and the meshing stiffness，as well as realize theshifting synchronous time of the transmission. These studies play an important role onthe design of a heavy-duty truck transmission which has reasonable structure, steadydrive, small vibration as well as high efficiency.The research is focused on the rear auxiliary transmission for a heavy-duty trucktransmission in this thesis. The dynamics of the spur planetary gear structure in the rearauxiliary transmission have been studyed with the theoretical analysis and numericalsimulation. The shifting synchronous time of the rear auxiliary transmission have beenalso studied based on theoretical analysis, numerical simulation and experimentalresearch. The definite research contents are as follows:1). The parts of the rear auxiliary transmission in a heavy-duty truck transmissionare modeled and assembled in the software UG through parameterization. The directapproach are utilized for the modeling of the translation-torsion coupling model, withconsideration of the ring gear flexibility that the spring-joint rigid ring gear segmentsmodel are used for the flexibile ring gear model. The theoretical basis of the equivalentanalysis for dynamic modeling has also been introduced.2). The lumped parameter model of the spur planetary gear structure has been setup in the multibody dynamics simulation software–ADAMS. The softwaresMSC.PATRAN/NASTRAN have been used to deal with the flexibility of the ring gear.The inherent characteristic of the spur planetary gear structure has been analysised inthe modules of the ADAMS/Vibration and ADAMS/View. The influence on the naturalfrequencies by the mass of the parts and the meshing stiffness have also been simulatedrespectively. Based on the Hertz elastic contact theory, the gear contact has beensimulated after the deduce of the gear contact simulation parameter, and has beencompared with the theoretical results.3). The shifting synchronous time and the force analysis in the shifting process forthe rear auxiliary transmission have been studied theoretically. With consideration of the ring gear flexibility, the shifting synchronous time of the rear auxiliary transmissionhave been simulated in ADAMS software assuming that the ring gear is rigid body andflexible body respectively. The experimental research of the shifting synchronous timehas also been performed, and the relative errors of the theoretical analysis results andthe simulation results of the synchronous time have also been compared with theexperimental results.