农业拖拉机用多段液压机械无级变速器设计

提出一种由单个普通行星排构成的简单高效拖拉机用多段液压机械无级变速器传动结构，分析了变速器的变速特性、转矩特性、平稳换段条件和液压功率分流比，通过装机实例表明其无级变速范围宽，在车辆常用工作速度段液压功率分流比低于20%，在与中耕、犁耕、运输作业对应的高、中、低速度区间可分别实现3个高效率纯机械档，有利于提高车辆的动力性和经济性。

Design of a multi-range hydrostatic mechanical transmission for farm tractors

This paper provided a simple structure and high efficiency multi-range hydrostatic mechanical transmission composed of a single common planetary gear train for farm tractors. The changing characteristics of speed and torque, the synchronized range shifting condition and the distribution ratio of hydraulic power were analyzed. The utilized instance presents that the continuously variable speed range is wide. The distribution ration of hydraulic power is less than 20% in the common work speed range of tractors. There are three high efficiency pure mechanical gears in every range of low, middle, and high speed corresponding to cultivating, plowing and transporting. It is useful to improve power and economic capabilities of vehicles.