挖掘机提升系统多自由度动力分析与计算

Multi Degrees of Freedom Dynamic Analysis and Calculation on Hoisting System of Mechanical Excavator

从系统论的思想出发,以提升系统的驱动力矩为广义力,运用动力学理论和拉格朗日方程法建立提升系统多自由度的弹性体、刚体混合系统的动力学模型;以堵转工况、斗杆垂直动臂并全伸出状态为计算条件,采用矩阵迭代法和编程计算提升系统的振动响应,计算出高速轴和提升钢丝绳的动载荷系数为1.343和1.374;计算并分析了堵转时间及不同土壤刚度因素对提升系统动载荷的影响关系曲线,得出了不同土壤刚度的动载荷系数.同时,为降低动载荷并保证设备安全工作,建议堵转时间不宜超过2.0 s.

According to the thoughts of the system theory, taking the driving moment of hoisting system as generalized force, a dynamic model of elastomer and rigid body with many freedom degrees for hoisting system was established using the dynamic theory and Lagrange equation method. The vibration response of hoisting system was calculated based on the matrix iterative method under conditions of locked rotor and vertical boom spreading of bucket rod. The calculated dynamic load coefficient of the high-speed shaft and the hoisting rope is 1. 343 and 1. 374, respectively. The effects of locked-rotor time and soil stiffness on the dynamic load of hoisting system were analyzed and accordingly the dynamic load coefficients with different soil stiffness were obtained. To reduce dynamic load and ensure the safe functioning of device, the locked-rotor time should not be more than 2.0 s.