1、 I 摘 要 课题来源于生产实际，依据机动车安全技术条件和汽车机械 变速器总成技术条件 ，针对低速载货汽车的运行特点而设计。参与了汽 车的总体设计，确定了汽车的质量参数，选择了合适的发动机，并且计 算出汽车的最高速度。 关于变速器的设计，首先选择标准的齿轮模数，在总档位和一档速 比确定后，合理分配变速器各档位的速比，接着计算出齿轮参数和中心 距，并对齿轮进行强度验算，确定了齿轮的结构与尺寸，绘制出所有齿 轮的零件图。根据经验公式初步计算出轴的尺寸，然后对每个档位下轴 的刚度和强度进行验算，确定出轴的结构和尺寸，绘制出各根轴的零件 图。根据结构布置和参考同类车型的相应轴承后，按国家标准选择合适
2、的轴承，然后对轴承进行使用寿命的验算，最终完成了变速器的零件图 和装配图的绘制。 此变速器的齿轮都为标准齿轮， 档位数和传动比与发动机参数匹配， 保证了汽车具有良好的动力性和经济性。该变速器具有操纵简单、方便、 传动效率高、制造容易、成本低廉、维修方便的特点，适合低速载货汽 车的使用。 关键词：低速载货汽车；变速器；设计 II Abstract The topic comes from the production reality, which is based on the safety specifications for power driven vehicles operating o
3、n roads and the specifications for the automobile mechanical transmission. It designs the low-speed trucks movement characteristic. The automobile quality parameters are determined, according to the automobile system design, choosing the appropriate engine, and calculating the maximum speed. When de
4、sign the transmission, first, we choose the standard gear modulus and determine all speeds proportions after we choose the number of the transmissions gears and the first gear, then calculate the gears parameter and the center distance, and the gear needs the intensity checking calculation. We deter
5、mine gears structure, then complete drawing of the gears component. According to the empirical formula, we preliminary carry on the checking calculation to each gears rigidity and the intensity to determine the axis structure and size, and thus draw up various axis component drawing. After arranged
6、structure and compared with the similar type of vehicles bearing, according to the national standard, we select the appropriate bearings, and then calculate the service life of the bearings. Finally drawing of the component and the assembly of the transmission are completed. Because the transmission gear is the standard gear and the number of gears and speeds proportions match to the engine conditions, which ensure the necessary power and economy. This transmission has many me
