目 录

设计任务书························································2 第1章 整车主要目标参数的初步确定·································3 1.1、发动机的选择·················································3 1.1.1、发动机的最大功率及转速的确定·······························3 1.1.2、发动机的最大转矩及转速的确定·······························4 1.2、轮胎的选择···················································4 1.3、传动系最小传动比的确定·······································5 1.4、传动系最大传动比的确定·······································6 第2章 传动系各总成的选型·········································7 2.1、发动机的选型·················································7 2.2、离合器的初步选型·············································9 2.3、变速器的选型················································10 2.4、传动轴的选型················································11 2.5、驱动桥的选型················································11 2.5.1、驱动桥结构形式和布置形式的选择····························11 2.5.2、主减速器结构形式选择······································12 2.5.3、驱动桥的选型··············································12 第3章 整车性能计算··············································12 3.1、配置潍柴WD615.50发动机时的整车性能计算·····················12 3.1.1、汽车动力性能计算··········································13 3.1.2、汽车经济性能计算··········································17 第4 章 发动机与传动系部件的确定·································18 设计总结·························································19 致谢·····························································19 参考文献·························································20 附录·····························································21

1

设计任务书

载货汽车汽车动力总成匹配与总体设计

1、设计题目

载货汽车动力总成匹配与总体设计 2、性能参数要求

根据给定参数，设计一辆最高速度≥90km/h、最大爬坡度≥30%的载货汽车。

整车尺寸（长*宽*高） 11976mm*2065mm*3390mm 轴数4 轴距 （5750+1350）mm 额定载质量 20000kg 整备质量 12000kg 公路行驶最高车速 90km/h 最大爬坡度 ≥30% 2、具体设计任务

1) 查阅相关资料，根据设计题目中的具体特点，进行发动机、离合器、变速箱

传动轴、驱动桥以及车轮的选型。

2) 根据所选总成进行汽车动力性、经济性的估算，实现整车的优化配置。 3) 绘制设计车辆的总体布置图。 4) 完成至少1万字的设计说明书。

2

第1章 整车主要目标参数的初步确定

1.1 发动机的选择

1.1.1 发动机的最大功率及转速的确定

汽车的动力性能在很大程度上取决于发动机的最大功率。参考该题目中的参数，要求设计的载货汽车最高车速是ua=90km/h，那么发动机的最大功率应该大于或等于以该车速行驶时，滚动阻力功率与空气阻力功率之和，即

1magfCDA3(umax?uamax) （1-1） Pemax??T360076140式中，Pemax是发动机的最大功率（KW）；ηT是传动系效率（包括变速器、辅助变速器传动轴万向节、主减速器的传动效率），ηT=95%*95%*98%*96%=84.9%，传动系各部件的传动效率参考《汽车设计课程设计指导书》表1-1得；Ma是汽车总质量，Ma=32000kg；g是重力加速度，g=9.8m/s2；f是滚动阻力系数，由试验测得，在车速不大于100km/h的情况下可认为是常数。取f=0.010，参考《汽车设计课程设计指导书》表1-2得；CD是空气阻力系数，一般中重型货车可取0.8～1.0，这里取CD=0.9；A是迎风面积（㎡），取前轮距B1*总高H，A=2.065×3.390㎡。

CDA?0.9?2.065?3.390m2?6.3m2

故

132000?9.81?0.0100.9?2.065?3.390Pemax?（?90??903）KW?163.49KW0.849360076140

也可以利用比功率的统计值来确定发动机的功率值。

如选取功率为163.49KW的发动机，则比功率为

1000Pemax1000?163.49?KW/t?5.109KW/t

ma320003