汽车变速器设计.doc

汽车变速器设计 本科生毕业设计(论文) 摘 要 现代汽车上广泛采用活塞式内燃机作为动力源，其转矩和转速变化范围较小，而复杂的使用条件则要求汽车的驱动力和车速能在相当大的范围内变化。为解决这一矛盾，在传动系统中设置了变速器。 变速器是汽车重要的传动系组成，在较大范围内改变汽车行驶速度的大小和汽车驱动轮上扭矩的大小。变速器的结构对汽车的动力性、经济性、操纵的可靠性与轻便性、传动的平稳性与效率有很大的影响。本次设计的变速器具有重要的实际意义。 本次变速器布置方案采用中间轴式6+1挡和锁销和锁环式同步器换挡，并对倒挡齿轮和拨叉进行合理布置，其中第一轴和第二轴的轴线在同一直线上。这种布置形式缩短了变速器轴向尺寸，在保证挡数不变的情况下，减少齿轮数目，从而使变速器结构更加紧凑。 在确定了基本结构和给定的数据基础上,确定各档传动比,设计两轴中心距,轴的直径,进一步算得各档啮合齿轮的基本参数,进而对齿轮和轴进行校核，同时对轴承进行了选择。 在设计过程中，利用CAXA绘图。进行校核。 通过本次设计，使所设计的变速器工作更可靠，传动效率更高。 关键词:变速器;同步器;齿轮;传动轴 I 本科生毕业设计(论文) Abstract Modern car widely used internal combustion engine piston as power source, the torque and speed range, and the use of smaller complex condition of the requirements of the driving force and speed of the car in considerable scope changes. To solve the contradiction in transmission system, set up a transmission. The transmission gearbox, as an important part in automobile driving system is used to make up the shortcoming of engine torque and rotary speed. The structure of the vehicle’s Transmission will affect economy, reliability and portability of operation. The design of transmission has important practical significance. A scheme of structure with 6 forward shifts and 1 reverse shift. and synchronizer was adopted here, Combine to pour to block wheel gear and stir fork to carry on a reasonable decoration .where the first and second shafts were arranged in line. This kind of structure reduces the gearbox dimension in the axis direction, in assurance block to count under the constant circumstance, decrease wheel gear number. Therefore makes the designed transmission gearbox more compact. With the basic structure and given data, transmission ratio is determined, centre distance of the two shafts and the diameter of shaft are calculated. Then the basic parameter of gears and the check of the gears and shafts are finished. In addition, the bearing parameters is selected. The engingneering drawing is done by CAXA software.The checking for gears ang shaft i