Ⅰ摘要本设计的任务是设计一台用于货车上的手动变速器。本设计采用中间轴式变速器.根据轿车的外形、轮距、轴距、最小离地间隙、最小转弯半径、车辆重量、满载重量以及最高车速等参数,结合自己选择的适合于该货车的发动机型号可以得出发动机的最大功率、最大扭矩、排量等重要的参数。再结合某些货车的基本参数，选择适当的主减速比。本次设计的汽车变速箱主要是从强度方面来对齿轮的尺寸计算及校核，轴的尺寸计算和位置的确定，选择设计满足其承载能力的同步器。另外，针对齿轮作用力的不同，在不同的轴上选择合适的轴承。利用软件Pro/e和CAD完成变速器总成图、第一轴、第二轴、中间轴、各个挡齿轮及同步器的设计。关键词：变速器；锁环式同步器；传动比；中间轴；货车=2\*ROMANIIABSTRACTThedutyofthisdesignistodesignamanualtransmissionusedinthetruck,It’sthecountershaft-typetransmissiongearbox.Accordingtothecontour,track，wheelbase，thesmallestgroundclearance,thesmallestturningradium,thevehiclesweight,theall-upweightaswellasthehighestspeedandsoon,unionthechoosingenginemodelwecanobtaintheimportantparametersofthemaxpower,themaxtorque,thedisplacementandsoon.Accordingtothebasicparametersofthecertainsaloon,choosethesuitablefinaldriveratio.Thisdesignismainlygear'ssizecomputationandtheexamination，theaxissize'scalcul-ationandtheposition'sdetermination，thechoicedesignsatisfiesitsbearingcapacitythesyn-chromesh.Moreover，inviewofthegearaction'sdifference,choosestheappropriatebearingonthedifferentaxis．Completesthetransmissiongearboxunitchart，thefirstaxis，thesecondaxis,theintermediateshaftusingsoftwarePro/EandCAD,tokeepoffthegearandthesynchromeshdesignonebyone．Keywords:transmission;inertialtypeofsynchronizer;gearratio;countershaft；truck目录摘要.................................................................ⅠAbstract..............................................................Ⅱ第1章绪论...........................................................11.1概述.................................................................11.2国内外研究现状.......................................................11.3研究内容........................................................3第2章变速器传动机构布置方案.......................................42.1传动机构布置方案分析.................................................42.2传动装置布置方案分析.................................................42.3本章小结............................................................7第3章变速器主要参数的选择