新型多段液压机械无级变速器效率特性分析

Efficiency Analysis of an Innovational Multi-range Hydro-mechanical Continuously Variable Transmission

介绍了泵、马达的近似效率计算公式和闭式变量泵-马达系统效率随转速、油压、排量变化的算法。导出了闭式行星齿轮传动产生功率循环的条件和液压机械无级变速器(HMCVT)典型结构的效率计算公式。描述了包含输入功率、泵马达排量、功率循环等因素时效率计算的合理步骤,对新型多段HMCVT进行了效率计算。结果表明:新型多段HMCVT的平均效率高于0.93,但随传动比、传递功率及转速的变化存在波动;控制传动比在泵排量为零的附近调节,可保证HM-CVT高效率工作。

To study the calculating method of the total efficiency of the innovational multi-range hydro-mechanical continuously variable transmission （HMCVT） when factors of the power cycle and the variation of the efficiency of hydraulic units with their input power are considered. An approximate efficiency formula of hydraulic units was established, an efficiency algorithm of the closed pump-motor system, which varies with the speed, pressure and displacement of hydraulic units was given, the conditions of existence of the power cycle in the closed planetary gear transmission were derived, the efficiency formulas of typical structures of HMCVT were presented, and a reasonable efficiency calculating procedure was described. The efficiency of the innovational multi-range HMCVT was calculated by this procedure. The result shows that the average efficiency of HMCVT is higher than O. 93, although the efficiency varies with the transmission ratio, the input power and speed. The HMCVT can work in high efficiency ranges by properly adjusting its transmission ratio into the ranges that the pump displacement is near to zero.