基于单元建模法的怠速工况传动系建模及多种扭转减振器性能对比

Modeling of idle speed transmission based on unit modeling method and performance comparison of various torsional dampers

采用单元建模法建立怠速工况传动系四自由度扭振模型,并对3种扭转减振器进行仿真对比。首先,为了能准确反映发动机动态扭矩波动对传动系扭振的影响,建立发动机准瞬态模型,并考虑动态摩擦力矩对其输出扭矩的影响;其次,对现有应用较为广泛的离合器扭转减振器、双质量飞轮扭转减振器以及一种新型离心摆式双质量飞轮进行非线性建模;同时对变速箱怠速工况常啮合齿轮对进行精确建模,并考虑齿轮啮合间隙、时变啮合刚度以及从动齿轮转动过程产生拖曳力矩等因素对模型精度的影响;然后对扭振模型进行试验验证;最后利用所建模型对3种扭振减振器性能进行对比分析。研究结果表明:仿真结果与试验结果基本一致,模型精度高,满足工程仿真需求;安装离心摆的新型扭转减振器减振性能最好,怠速工况振动衰减幅度达70%,能够进一步提升车辆NVH性能。

A four-degree-of-freedom torsional vibration model of transmission system under idle condition was established by using unit modeling method,and three kinds of torsional dampers were simulated and compared.First of all,in order to accurately reflect the effect of engine dynamic torque fluctuation on the torsional vibration of the drive train,the Quasi-Transient model of the engine was established,and the influence of dynamic friction moment on its output torque was considered.Secondly,nonlinear modeling was applied to clutch torsional vibration damper,dual mass flywheel(DMF)torsional vibration damper and a new centrifugal pendulum dual mass flywheel.At the same time,the accurate model of gear pair with constant meshing in idle condition of gearbox was established,and the influences of factors such as gear meshing clearance,time-varying meshing stiffness and drag torque generated by the driven gear rotation process on the model accuracy were considered.Then the torsional vibration model was tested and verified.Finally,the performances of the three torsional vibration dampers were compared and analyzed by the model.The results show that the simulation results are basically consistent with the test results,and the model has high precision and meets the engineering simulation requirements.The new type of torsional dampers with centrifugal pendulum has the best vibration reduction performance,and the vibration attenuation range is more than 70%at idle speed,which can further improve the vehicle NVH performance.