变量泵控变量马达闭式液压系统效率模型建立与实验

Establishment and Experiment of Efficiency Model for Closed-loop Hydraulic System with Variable Displacement Pump and Variable Displacement Motor

摘要:

为明晰变量泵控变量马达闭式液压传动系统效率特性,本文采用理论与实验测试相结合的方法,系统研究其传动特性。采用集总阻力参数表征系统损失,并以此建立传动系统效率模型。依托实验平台,对模型各阻力参数特性进行辨识。基于所建效率模型,预测了系统转差率、扭矩损失和传动效率等参数随负载特性的变化规律,并通过实验验证了模型的有效性。同时,探究了油液温度对系统效率特性的影响规律。研究结果表明:所建模型可有效表征系统传动效率特性,当负载扭矩在20 ~ 40 N·m时,先泵后马达的顺序排量调节规律可获得最高传动效率,最高可达55%。此外,在40 ~ 70℃的油温区间内,泵控工况下的系统效率随油温升高而增大,而在马达控制工况下,油温升高将降低系统效率,且减小幅度随马达转速的升高而显著增大。本研究明确了该类液压传动系统的效率特性规律,为设计合适的控制策略,获得最佳驱动性能提供了一定的理论参考和工程支撑。

Abstract:

Aiming to clarify the efficiency characteristics of the closed-loop hydrostatic system with variable pump controlled variable motor, the combined theoretical and experimental approach was adopted to systematically investigate the efficiency performance. The lumped resistance parameters were employed to characterize the system losses, based on which the system efficiency model was established. Through an experimental platform, the characteristics of each resistance parameter in the model were identified. Based on the established efficiency model, the variation laws of system parameters such as slip, torque loss and efficiency with load were predicted, and the validity of the model was verified by experiments. Meanwhile, the influence of oil temperature on the system efficiency characteristics was explored. The results showed that the established model can effectively characterize the drive efficiency of the system. When the load torque was with the range of 20 ~ 40 N·m, the sequential displacement adjustment strategy can achieve the highest drive efficiency, up to 55% . In addition, within the oil temperature range of 40 ~ 70℃, the system efficiency under pump control was increased with the rising of oil temperature, whereas under motor control, increasing oil temperature reduced the system efficiency, and the reduction magnitude became significantly larger with the increase of motor speed. The research result clarified the efficiency characteristics of this type of hydrostatic drive system, providing theoretical reference and engineering support for designing appropriate control strategies and achieving optimal driving performance.