According to the typical working conditions of a loader and considering the complexity of the working conditions, the hydrodynamic transmission powertrain system was modeled in this study. Because the hydrodynamic torque converter is a flexible fluid transmission component in the transmission system, this study proposes and establishes equivalent variable damping and equivalent variable stiffness models of the hydrodynamic torque converter. Based on this, a torsional vibration simulation model of the loader with variable damping and stiffness is proposed, and the frequencies and amplitudes of the torsional resonance modes of the transmission system varying with engine speed and hydrodynamic torque converter speed ratio are obtained. It is determined that the variable stiffness of the hydrodynamic torque converter has little effect on the natural frequency of the vehicle, and taking variable damping and stiffness as input, the natural frequency and resonance points of the transmission system can be calculated more accurately. The simulation modeling and calculation approach are experimentally verified, and the simulation results are valid and closer to the real resonance.

根据装载机典型工况，考虑工况复杂性，对液力传动动力总成系统进行建模。由于液力变矩器是传动系统中的柔性流体传动部件，本研究提出并建立了液力变矩器的等效变阻尼和等效变刚度模型。在此基础上，提出了一种变阻尼变刚度装载机扭转振动仿真模型，得到了传动系统扭转共振模态随发动机转速和液力变矩器速比变化的频率和幅值。确定了液力变矩器的变刚度对车辆固有频率的影响很小，以变阻尼和变刚度为输入，可以更准确地计算传动系统的固有频率和共振点。仿真建模和计算方法经过实验验证，仿真结果有效且更接近真实共振。