Research On Torsional Vibration Of Vehicle Driveline

Torsional vibration of the vehicle from the driveline is the mainly factor that contributes to the automobile's structure vibration and its interior noise, it has great effect on the vehicle's NVH quality. With the promotion of the auto's power, the requirements of light-weight structure and the rising standard of comfortable riding, the problem of torsional vibiration of the vehicle from the power transmission system is becoming more and more prominent. Torsional vibration damper has good effect on changing the natural frequency of the transmission system, reducing torsional vibration and the dynamic loads between the shafts, and also, eliminating the vibration noise, so the research of torsional vibration damper has important practical significance.In this paper, the torsional vibration characteristics of the vehicle's transmission system has been studied, the vehicle is assembled with DF515A vibration damper. First, according the structure characteristics of the vehicle's transmission system, the method of lumped-mass method is used to conduct equivalent conversion of the parts in the vehicle's tranmission system, the torsional vibration model and mathematical model of the idling process and driving conditions are established. The damp characteristics of the DF515A vibration damper is analized and its mathematical expression of equivalent damp is established too. At last, the characteristics when it is subjected to the periodic disturbance torque is analized.The natural frequency and principal mode analysis are conducted with the formal model ,research shows that the DF515A vibration damper can transfer most natural frequency out of the motor's speed range which are normal used, reduce the probablity of system resonance. The Newmark-βnumerical simulation algorithm is applied to get the transient response when the transmission system is inspired by the engine. It shows that the damper has certain attenuation effect on the torsional vibration which still needs to be improved.In order to develop the dampering charasteristics of the vibration damper, the optimization module of ADAMS is used. The optimized object is minimizing the driven part's amplitude of angular speed fluctuation during the torsional vibration. The driven part's inertia, torsional rigidity and damping coefficient is optimized with the reduced gradient method, the optimization results of the main parameter of the vibration damper is got. After optimization, not only the attenuation is increased nearly 30% , the natural frequency of the power transmission system are completely removed from the engine speed range, the vibration reduction and isolation purpose are better realized , important reference for the improvement of vibration is provided.