机械式四档变速器设计 【汽车专业毕业论文】【答辩通过】

汽车专业毕业论文---答辩通过极具参考价值本论文材料仅供参考学习，疑问可咨询文档贡献者。目录摘要························································3Abstract····················································3变速器的简介················································41.变速器传动机构的方案分析································62.变速器零、部件结构方案分析······························73.变速器操纵机构··········································81.变速器的参数选择··········································81.1一档齿轮齿数的确定····································81.2中心距A的选择········································91.3确定齿轮参数·········································101.3.1齿宽选择·······································101.3.2压力角·········································111.3.3齿轮螺旋角·····································111.3.4校验齿轮的接触强度·····························111.4变速器轴向尺寸·······································131.5轴的直径·············································131.6各档齿轮齿数的分配···································141.6.1确定常啮合传动齿轮副的齿数·····················141.6.2确定其他各档的齿数·····························152.变速器传动···············································162.1传动简图·············································162.2同步器（简介）········································162.2.1惯性式同步机···································182.2.2同步器工作原理·································182.2.3齿轮材料·······································192.2.4齿轮材料、热处理·······························202.2.5齿轮精度等级···································203.故障诊断与检修···········································213.1常见故障与检修·······································213.1.1变速器的异常声响·······························213.1.2变速器跳档·····································223.1.3挂档困难·······································223.1.4变速器乱档·····································233.1.5变速器发热·····································233.1.6变速器漏油·····································243.2变速器零件的检修·····································24汽车专业毕业论文---答辩通过极具参考价值本论文材料仅供参考学习，疑问可咨询文档贡献者。3.2.1齿轮与花键的检修·······························243.2.2轴的检修·······································243.2.3锁环式变速器的检修·····························244.变速器的润滑·············································254.1润滑的基本知识·······································254.2变速器润滑油·········································254.3变速器润滑系统·······································254.4变速器零件的清洗·····································265.变速器的装配·············································265.1变速器装配注意事项··································265.2变速器总成的装配····································275.3中间轴后轴承间隙调整方法·····························28英文说明···················································29参考文献···················································30致谢···················································31汽车专业毕业论文---答辩通过极具参考价值本论文材料仅供参考学习，疑问可咨询文档贡献者。摘要变速器是汽车传动系中最主要的部件之一。变速箱由变速传动机构和变速操纵机构两部分组成。变速传动机构的主要作用是改变转距和转速的数值和方向；操纵机构的主要作用是控制传动机构，实现变速器传动比的交换，即实现换档，以达到变速变距。关键字：变速传动机构、变速操纵机构、齿轮AbstractBecomesoonboxformbecometospreadtomovetheorganizationandbecomesoontomanipulatetheorganizationtwopartstoconstitutesoon.Mainfunctionthatbecomestospreadtomovetheorganizationsoonisthechangeturnstheandturnsoonofthenumberandthedirection;Themainfunctionthatmanipulatestheorganizationisacontroltospreadtomovetheorganization,carryoutthetransformationthatthegearboxspreadstomovetheration,thentherealizationshiftgear,toattaintobecometochangethesoon.Keywords:Variable-speedcontrolmechanism，speedchangecontrolMechanism,gear.汽车专业毕业论文---答辩通过极具参考价值本论文材料仅供参考学习，疑问可咨询文档贡献者。变速器简介我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。因此，我们希望发动机总是在最好的状态下工作。但是，汽车在使用的时候需要有不同的速度，这样就产生了矛盾。这个矛盾要通过变速器来解决。汽车变速器的作用用一句话概括，就叫做变速变扭，即增速减扭或减速增扭。为什么减速可以增扭，而增速又要减扭呢？设发动机输出的功率不变，功率可以表示为N=Wt,其中w是转动的角速度，T是扭矩。当N固定的时候，w与T是反比的。所以增速必减扭，减速必增扭。汽车变速器齿轮传动就是根据变速变扭的原理，分成各个档位对应不同的传动比，以适应不同的运行状况。一般的手动变速器内设置输入轴、中间轴和输出轴，又称三轴式，另外还有倒档轴。三轴式是变速器的主体结构，输入轴的转速也就是发动机的转速，输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比，也就有了不同的转速。我们设计的手动变速器，它的传动比分别是：1档3.545：1；2档2.105：1；3档1.429：1；4档1：1。如图所示：当汽车启动司机选择1档时，拔插将1/2档同步器向后结合1档齿轮并将它锁定输出轴上，动力经输入轴、中间轴和输出轴上的1档齿轮，1档齿轮带动输出轴，输出轴将动力传递到传动轴上，。典型1档变速器齿轮传动轴是3.545：1，也就是说输入轴转动3.5圈，输出轴转1圈。当汽车增速司机选择2档时，拔叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上，动力传递路线相似，所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.105：1，输入轴转2圈，输出轴转1圈，比1档转速增加，扭矩降低。当汽车增速司机选择3档时，拔叉将1/2档同步器回到空档位置，又使汽车专业毕业论文---答辩通过极具参考价值本论文材料仅供参考学习，疑问可咨询文档贡献者。3/4档同步器移动直至将3档齿轮锁定在输出轴上，使动力可以从输入轴-中间轴-输出轴上的3档变速齿轮，通过3档变速齿轮带动输出轴。典型3档传动比是1.5：1，输入轴转1.5圈，输出轴转1圈是进一步的增速。如图所示：当汽车加油增速司机选择4档时，拔叉将3/4档同步器脱离3档齿轮直接与输入轴主动齿轮接合，动力直接从输入轴传递到输出轴，此时传动比1：1，即输出轴与输入轴转速一样。由于动力不经中间轴，又称直接档，该档传动比的传动效率最高。汽车多数运行时间都用直接档以达到最好的燃料经济性。换档时要先进入空档，变速器处于空档时变速齿轮没有锁定在输出轴上，它们不能带动输出轴转动，没有动力输出。一般汽车手动变速器传动比主要分上述1-4档，通常设计者首先确定最低（1档）与最高（4档）传动比后，中间各档传动比一般按等比级数分配。倒档时输出轴要向相反的方向旋转。如果一对齿轮啮合时大家反向旋转，中间加上一个齿轮就会变成同向旋转。利用这个原理，倒档就要添加一个齿轮做“媒介”，将轴的转动方向掉转，因此就有了一根倒档轴。倒档轴独立装在变速器壳内，与中间轴平行，当轴上齿轮分别与中间轴齿轮和输出轴齿轮啮合时，输出轴转向会相反。通常倒档用的同步器也控制1档的接合，所以1档与倒档位置是在同一侧的。由于有中间齿轮，一般变速器倒档传动相近与1档传动比。从驾驶平顺性考虑，变速器档位越多越好，档位多相邻档间的传动比的比值就变化小，换档容易而且平顺。但档位多的缺点就是变速器结构复杂，体积大，现在轻型汽车变速器一般是4-5档。同时，变速器传动比都不是整数，而且都是带小数点的，这是因为啮合齿轮的齿数不是整倍数所致，轮齿数是整倍数就会导致两齿轮啮合面磨损不均匀，使得轮齿表面质量产生较大的差异。变速器的功用是在不同的使用条件下，改变发动机传到驱动轮上的转距和转速，使汽车得到不同的牵引力和速度，同时使发动机在最有利的工况范围