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1、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
2、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，特性分析全套图纸，加153893706 CHARACTERISTICS ANALYSIS OF HYDRO-MECHANICAL CONTINUOUSLY VARIABLE TRANSMISSION OF TRACTOR ABSTRACTT
3、o 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) ,
4、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 sh
5、ow 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 regulat
6、ion 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 manufacture and use of low cost; Gearbox
7、 shift structure of the sliding gear shift, it is relatively simple structure, convenience. Input shaft and output shaft rectangular spline shaft, the gear is also used rectangular key to input or output shaft linked. Farm tractor gearbox in the design, Main Gearbox transmission ratio is the basis f
8、or determining the main users of agricultural operations in the course of speed needs and the needs of tractor work to be determined, therefore, the current design of the first tractor to determine the structure of the transmission system, then divided speed, thereby delimiting the 3 km/h 9km/h and
9、9km/h 30 km/h speed of the two main areas, calculate and determine each blocks speed and the transmission ratioes, the design process to determine the necessary structural components, Bearing under which the need to use a deep groove ball bearings and cylindrical roller bearings these two types of b
10、earings, and then the final structure of its various components of the check, and eventually met the requirements of design. KEY WORD：tractor, gearbox ratio, continuously variable transmission,hydro-mechanical transmission , Characteristics analysis 符 号 说 明：第i个齿轮：第i和第j个齿轮的传动比：齿轮模数 ：第i轴的转矩 ：齿数：机械效率：节
11、点处压力角 ：啮合角 ：弯曲应力 ：接触应力 ：发动机标定转速 ：驱动轮动力半径 ：发动机最大输出扭矩 名义计算载荷：配合齿轮的总齿数：弹性模量 ：第i档颈向力 ：第i档左侧颈向力 ：第i档右侧颈向力 ：中心距 ：拖拉机第j挡理论工作速度 目 录第一章 前言.11.1对变速器的要求 .11.2变速器的分类.1第二章 传动方案的确定.4 2.1传动方案的选择.42.2 传动方案的比较.4 2.3 传动方案的分析.6第三章 传动参数的确定.9 3.1初步确定各段特性参数.9 3.2中心距的选择及传动比的分配及齿轮齿数的选择.11 3.3重新计算前进段的转速和突变点e .12 3.4 倒挡的计算 .
12、13 3.5计算各段的功率分流比.14第四章 齿轮的校核 . 16 4.1低速级齿轮的校核.16 4.1.1校核齿面的接触强度.16 4.1.2校核齿根弯曲疲劳强度 .17 4.2 倒挡第一级齿轮传动的校核.17 4.2.1校核齿面的接触强度.18 4.2.2 校核齿根弯曲疲劳强度.184.3各段齿轮参数.19第五章 离合器的选择 .215.1行星轮系离合器的计算.215.1.1 离合器C1的计算 .215.1.2 离合器C2、C3、C4的计算.225.2前进、倒档离合器的计算.23第六章 液压传动系统的选择.24 6.1 液压马达的选择.246.1液压泵的选择.24第七章 结论.25参考文献.26致谢.28第一章 前言汽车上广泛使用活塞式发动机，其输出转矩和转速变化都和小，而汽车在行驶时所遇到的复杂的道路条件和使用条件要求汽车的驱动力和车速能在相当大的范围内变化。为此，在汽车传动系统中设置了变速器。1.1对变速器的要求变速器用来改变发动机传到驱动轮上的转速和转矩，目的是在原地起步、爬坡、转弯、加速等各种情况下，使汽车获得不同的牵引力和速度，同
