【作者】 张建方；

【导师】 王勇；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 齿形链传动广泛应用于汽车和摩托车发动机的正时机构。然而传统的齿形链传动存在多边形效应和啮入瞬间的冲击效应,损害了传动的同步性与均匀性。因此亟需研究新型齿形链传动来提高齿形链机构的传动性能。首先本文分析了齿形链传动过程中存在的多边形效应和啮合冲击,以减小机构高速运转时链条与链轮的啮合冲击,降低链条的波动量,提高链传动的平稳性为目标,以基于MFC的ObjectARX开发环境为设计工具,以多体动力学分析软件ADAMS为仿真实验手段,开展了新型齿廓链轮的设计研究。基于链轮与紧边链条的啮合过程,利用计算机图形软件的布尔运算操作,模拟切削加工成型过程,提出了链条包络链轮毛坯生成链轮齿形的设计方法。提出了一种基于三维空间曲面(或实体)的扫掠实体模型特征的软件设计方法。开发了一套可在AutoCAD环境中建立各种参数的直齿圆柱齿轮模型的软件模块,并在此基础上开发了建立大负变位大压力角的渐开线链轮模型的软件模块。阐明了如何操纵AutoCAD数据库中有关实体进行位置变换的方法,尤其是进行旋转变换时坐标向量与变换矩阵的对应关系。进行了相关模型实例的误差分析,得出了模型齿廓曲面误差与建模过程中的分步数的关系。基于机械动态仿真技术建立了传统直边齿廓链轮、渐开线链轮与传统外啮合直齿链条相啮合的齿形链机构的多刚体系统动力学模型。利用机械系统多体动力学分析软件ADAMS,进行了主动链轮转速在500r/min-8000r/min时的动力学仿真试验。试验结果表明,同等条件下采用渐开线齿廓链轮与链板的啮合冲击比采用直线齿廓链轮时要小,但是紧边链条的波动量和从动轮转速的不均匀系数比直线齿廓链轮稍大。更多还原

【Abstract】 Silent chain drive is widely used in the timing mechanism of gasoline engine, such as motorcar and motorcycle engine. However the polygon movement and the meshing contact effect of silent chain drive damages the synchronization and uniformity of transmission. It is necessary to develope new kind of silent chain drive to improve the transmission performance of silent chain mechanism.First of all, the polygon movement and the meshing contact of silent chain drive were analyzed. In order to reduce the meshing impact between the silent chain and the sprocket, to decrease the fluctuation of the chain at the high-speed situation, and to improve the stability of the chain drive, taking ObjectARX based on MFC as the designing tool, and using ADAMS as the analyzing tool, the design of a new tooth profile sprocket was developed. Based on the meshing process between the sprocket and the tight-side chain, simulated the shaped process of cutting by taking use of the Boolean operation of the software, the paper indicated the design method using the chain to envelope the sprocket blank to generate the sprocket teeth.The thesis pointed out the developing aspect of the design software that a part modeling with the enveloped surface, which is swept by 3D solid or surface, can be created. The study developed a software insert that can generate all kinds of spur gear modeling in the environment of AutoCAD, and based on that the study developed a software insert which can generate the involute sprocket model with a large pressure angle and a big modification coefficient. The thesis illustrated how to operate the entities in the AutoCAD database to do the position transformation, especially showed the relationship between the transformation matrix and the vector coordinates while doing the rotating transformation. The paper made some deviation analyse on the given model, got the relationship between the step number and the deviation of the tooth surface.The rigid dynamic models of two silent chain mechanisms (including the beeline profile sprocket and the involute sprockets separately mesh with the normal silent chain) were built by means of the 3-D modeling and mechanical dynamic analysis technology. The dynamic simulation of drive wheel at speeds of 500r/min to 8000r/min was achieved. The analysis results show that the meshing impact of the involute sprocket mechanism is less than the beeline profile sprocket mechanism in the same conditions, and the tight-side fluctuation of the silent chain of involute profile sprocket mechanism is larger than that of the beeline profile sprocket mechanism, and the driven wheel angle velocity nonuniformity coefficient shows the same situation with the tight-side fluctuation of the chain.更多还原