多行星排机电复合传动特性分析

An Analysis on the Characteristics of Electromechanical Transmission with Multi-planetary Gearing

针对车辆常用机电复合无级传动的分速汇矩、分矩汇速和分速汇速3种功率耦合机构,分析了多行星排分流传动的转速、转矩和分流比特性,并对不同分流形式组合进行了分析。结果表明:多行星排分流特性与两行星排分流传动特性相同,分速汇矩式分流传动有一个机械点,在机械点之前分流比较小,适用于低速起步阶段;分矩汇速式分流有一个机械点,分流比成对称分布,传动比小于机械点时,成分流工况,效率高,适合于高速阶段。分速汇速式分流传动有两个机械点,在两个机械点之间分流比较小,适用于中高速阶段。对于多模式机电复合传动,低速起步采用分速汇矩式分流传动,中高速采用分速汇速式分流传动比较好,可实现电机无速差切换。

The characteristics of the speed,torque and split ratio of multi-planetary power split transmission are analyzed for input split,output split and compound split three power coupling mechanisms of vehicle electromechanical variable transmission（ EVT）,and the combinations of different power-split modes are analyzed. The results show that the characteristic of multi-planetary power split transmission is the same as the dual-planetary one.The input split transmission has one mechanical point,before which the split ratio is relatively low,is suitable for low-speed start-up stage. The output split mode has one mechanical point with a symmetric distribution of split ratio,and when transmission ratio is lower than mechanical point,the efficiency is high,suitable for high speed stage.The compound split has two mechanical points,between which the split ratio is relatively low with high efficiency,suitable for medium and high speed stages. For multi-mode EVT,it is recommended to adopt input split mode at low-speed start-up stage and adopt compound split mode at medium and high speed stages for achieving switch without speed difference.