橡胶履带牵引车辆改进设计（无极自动变速器方案设计）.pdf

橡胶履带牵引车辆改进设计（无极自动变速器方案设计） 摘 要 设计了一种液压机械无级变速器，该装置由一个单行星排机构、变量泵- 定量马达构成的液压传动系统和多档有级变速箱组成。在分析液压机械传动 形式和液压传动类型的基础上，确定了拖拉机的总体传动方案，对液压元件 及机械参数的选择方法进行了阐述，分析了变速器的无级调速特性。绘制了 理论牵引特性曲线，分析比较了改进前后牵引特性。装有液压机械无级变速 器的拖拉机实现了速度的连续无极变化，在任何牵引力时，发动机都在接近 于满负荷点工作，大大提高了拖拉机的生产效率和燃油经济性。 为了研究液压机械无级变速传动装置的特性，以东方红1302R 拖拉机机 械液压无级变速器为对象，建立起速比与变量泵和定量马达的排量比、液压 功率分流比、传动效率的关系式，绘制其特性曲线，给出各段工况下的功率 流向，分析循环功率存在条件及其对变速机构输出的影响。分析结果表明， 行星排特性参数、变量泵和定量马达排量比是影响变速机构速比、液压功率 分流比、功率及效率等特性的主要设计参数；机械液压无级变速器具有可控 的无极调速特性。 关键词：拖拉机，液压机械传动，无级变速器，特性分析 1 CHARACTERISTICS ANALYSIS OF HYDRO-MECHANICAL CONTINUOUSLY VARIABLE TRANSMISSION OF TRACTOR ABSTRACT To study the characteristics of hydro-mechanical continuously variable transmission device , based on the hydro-mechanical continuously variable transmission (HMCVT) of Donganghong 1302R tractor, the relation formulas of speed ratio of HMCVT with displacement ratio of variable hydraulic motor (MF) , hydraulic power distributing ratio and transmission efficiency are established. The characteristic curves of HMCVT are drawn. The power flow direction of each range is presented. The existing conditions of circulation power and its influence on mechanism out put are analyzed. The analysis results show that the characteristic parameter of planetary ear train and displacement ratio of PV and MF are the main design parameters that influence on the characteristics of speed ratio ,hydraulic power distributing ratio and efficiency of HMCVT ;the HMCVT has the characteristics of stepless speed regulation and high efficiency This main gearbox design is the two-axis gearbox, and the three-axis gearbox compared to its simple structure, compact, Except maximum block (not directly block), the other of the block of higher transmission efficiency, low noise, the manufa