机械5

新型微型拖拉机外观及主要部件结构设计 摘要 本设计的主要任务是研究微型拖拉机主要结构，包括驾驶楼外型及底盘主要部件的设计与改进。 驾驶楼设计部分是基于三维软件SolidWorks的设计。设计的原则是根据市场上客户的要求，即在实现驾驶楼的强度、刚度、尺寸等实用要求的同时尽量实现美学要求，以改变现今微型拖拉机驾驶楼不美观，结构设计不合理，而导致驾驶环境恶劣的现状。设计的步骤是首先确定总体尺寸，主要参考桃花江厂的现有车型的总体尺寸。外形要求再利用SolidWorks强大的曲面建模功能建模并改进，力求改进后的形状达到线条流畅，曲面圆润美观的效果。 底盘部分由大梁、变速箱，传动轴为主，其余部分参考外购件的参数加以整合设计。其中以底盘中的变速箱设计为重点。首先通过在工厂中实际的考察，确定各个档位的数据，包括车速，传动比，第二计算出变速箱的主要数据，比如中心距和传动齿轮模数，第三计算出其余需要的数据，比如轴承选用依据，轴段的设计，第四对各个部件进行力学的校核。 最后部分将介绍底盘的总体设计，底盘由离合器、变速器、万向节、传动轴和驱动桥组成。将会对大梁，发动机输出装置，进行设计；对外购件如传动轴将进行校核。 以上各步将全部采用solidworks软件进行计算机辅助设计，设计过程中经过较为精确的测量和计算后将所得的数据进行三维建模，利用模型进行模拟装配和干涉检查。构想通过创建三维模型这样一个平台来验证所做的设计，以便于对设计中的细节进行改进。 设计完成后，利用该模型的优点，即较为逼真地体现外型设计的效果及拖拉机的主要结构及尺寸关系，绘制二维的零件图，装配图和渲染效果图。 关键词：新型拖拉机；外型改进；3D曲面；变速箱设计 Abstract The mai
n missio
n of this desig
n studies is to implove the mai
n structure of the mi
niature tractor,i
nclude desig
ni
ng a
nd improvi
ng of cab a
nd mai
n parts of chassis. The cab desig
n is accordi
ng to the desig
n of 3D software SolidWorks. Pri
nciple of the desig
n is accordi
ng to customer's request, as far as possible co
nte
ntwith a
n esthetics request at the time of co
nte
ntwith the request of i
nte
nsity a
nd rigidity. At prese
nt mi
niature tractor cab be
not beautiful, structure desig
n
not reaso
nable, cause driver e
nviro
nme
nt thus bad. We hope that passi
ng this desig
n cha
nges this prese
nt co
nditio
n. The first is to certai
n total size a
nd the shape request, The seco
nd is to make use of the stro
ng fu
nctio
n of buildi
ng curved face of the SolidWorks to set up a mold. We hope after hard tryi
ng, Attai
n the effect that curved face be good-looki
ng a
nd the li
nes flowi
ng freely. The bedrock part is i
nclude of crossbeam, tra
nsmissio
n, a
nd tra
nsmissio
n shaft,a
nd improvi
ng the rest part by makmi
ng refere
nce of the parameter of spare parts that outside buys. The first is to pass a
n actual i
nvestigatio
n i
n the factory, make sure the data of each file,such as speed of avehicle a
nd tra
nsmissio
n of radio.The seco
nd is to compute becomes the mai
n datas of the tra
nsmissio
n,such as the ce
nter dista
nce a
nd the modulus of gears. The third computes the datas of
need,for example,the basis of choosi
ng beari
ngs. The fourth is to proofread each parts o
n the field of mecha
nics. Above each partwewill all use Solidworks software to carry o
n a CAD desig
n. Wewill use the datas that through accurate diagraph a
nd calculatio
n to set up a 3D mold. Make use of the model to imitate assemble a
nd check exactly if have a
n i
nterfere
nce. Hope toverify a desig
n a
nd modify a detail expedie
ntly by establish a model. After desig
ni
ng completio
n, make use of the adva
ntage of that model，that is to represe
nt mai
n structure a
nd size relatio
n of the tractorvivid
nessly a
nd the features desig
ns effect exactly。After thatwewill draw two-dime
nsio
nal spare parts drawi
ng paper, assemble drawi
ng paper a
nd exaggerate effect drawi
ng。 Keywords：
new type tractor；features improve；a curved surface；desig
n of tra
nsmissio
n 目录 引言4 1国内外研究现状和意义5 1.1国外研究现状5 1.2国内研究现状5 1.3课题研究的意义5 2方案选择6 2.1发动机布置方案的选择6 2.2车架的设计方案7 2.3驾驶楼的造型设计8 3驾驶楼外型设计10 3.1曲面的创建10 3.2车灯车窗的设计12 3.3引擎盖和车门的设计13 4齿轮式变速器设计16 4.1概述16 4.2确定各档车速18 4.3计算各档理论传动比18 4.4变速箱各前进挡传动齿轮的设计计算19 4.4.1精度选择19 4.4.2材料选择19 4.4.3确定主要参数和计算主要尺寸19 4.4.4接触疲劳强度的计算和校核20 4.4.5齿根弯曲强度的计算和校核22 4.5倒档各齿轮的设计22 4.5.1齿数和中心距的确定22 4.5.2分度圆直径23 4.5.3传动比误差23 4.6输入轴的设计和计算24 4.6.1输入轴参数24 4.6.2初步确定轴最小直径24 4.6.3轴段的设计24 4.6.4轴的强度计算校核25 4.6.5轴承的设计计算26 4.6.6花键的强度校核26 4.7倒档轴的设计和计算27 4.7.1倒档轴参数27 4.7.2初步确定轴最小直径28 4.7.3轴段的设计28 4.7.4轴承的设计计算29 4.7.5花键的强度校核29 4.8输出轴的计算及校核30 4.8.1输出轴参数30 4.8.2初步确定轴最小直径30 4.8.3轴段的设计30 4.8.4轴承的计算和校核31 4.8.4花键的强度校核31 4.9拨叉设计32 4.9.1初定拨叉形状33 4.9.2拨叉尺寸设计33 4.10箱体及其附件设计34 5拖拉机底盘的设计36 5.1车架设计36 5.1.1车架的结构36 5.1.2车架的强度校核37 5.3传动轴及其联轴器校核39 5.3.1十字轴万向节39 5.3.2传动轴设计40 6三维数字化建模42 6.1后桥42 6.1.1简介42 6.1.2建模细节42 6.2前桥及转向系统43 6.2.1简介43 3变速箱的三维建模44 6.4传动部分建模46 6.5发动机和驾驶楼等外型部件的安装46 7总结48 7.1毕设过程回顾48 7.1.1背景回顾48 7.1.2实地测绘48 7.1.3相关计算48 7.1.4计算机辅助三维设计49 7.1.5撰写和绘制图纸49 7.2产品改进前后效果对比50 7.3整车的一些参数53 谢辞54 参考文献55