【作者】 赵萍；

【导师】 郭培全；

【作者基本信息】 济南大学 ， 机械电子工程， 2006， 硕士

【摘要】 通过对现有各种CAD/CAM软件的分析,并结合平行分度凸轮机构设计的特点,选用Pro/E软件作为二次开发平台,利用Pro/TOOLKIT、Pro/Program、Visual C++构建了开发环境。利用相对运动法和等距曲线理论,导出了平行分度凸轮的廓形坐标方程,分析了平行分度凸轮的完全及不完全廓形,提出了平行分度凸轮廓形不发生干涉的条件:(1)若廓形上点的曲率中心在廓形的外侧,则该点的曲率半径不能小于滚子的半径;(2)分度廓形的导数连续。提出了机构连续传动的条件:(1)在任意时刻,每片凸轮都要与至少1个滚子啮合;(2)在任意时刻,至少有1个滚子处于凸轮的驱动区域。导出了平行分度凸轮机构压力角方程,对平行分度凸轮机构的压力角进行了分析,在凸轮驱动滚子的区域内,滚子半径rr越大,压力角越大;滚子分布圆半径rd越大,压力角越小。顶圆半径R a越小,压力角取值范围越小。进行了平行分度凸轮机构的运动学分析,盖特曼运动规律和变余弦运动规律输出角位移θ和角速度ω的变化规律相似,均为间歇运动输出;角加速度a的变化规律却有着本质的区别,变余弦运动规律时,角加速度有突变;盖特曼运动规律时,角加速度没有突变。在动力学研究中,对平行分度凸轮机构进行了简化,以啮合点为界线,将系统分为输入、输出两个子系统,这两个子系统在啮合点处通过力和位移的偶合相互联系。将输入子系统和输出子系统简化成分别由等效转动惯量、等效刚度、等效阻尼组成的单自由度动力学模型,导出了扭转振动的动力学方程,导出了基于数值计算思路的解的表达式,并进行了动力学仿真分析,得出结论:输入转速对最大振幅的影响非常之小,可以认为输入转速不影响最大振幅;但是,输入转速影响振动的形态,主要原因是输入转速的变化改变了激振频率。动程角对振动有明显的影响,动程角越小,振动越严重。在参数相同时,变余弦运动规律对应的最大振幅小于盖特曼运动规律对应的最大振幅;但是,在离开分度区进入位置保持区的过程中,两种运动规律对应的振动情况差异很大,盖特曼运动规律对应的振动衰减的早且快,原因在于加速度没有突变。构建了系统框架,规划并实现了各模块功能。在CAD模块的开发过程中,详细介绍了凸轮廓形的形成过程和廓形数据的计算,介绍了CAD框架和零件建模与装配的实现。在CAM模块的开发过程中,CAM模块系统的实现是利用Access数据库技术和VC++开发的动态连接程序,以菜单的形式加载,供Pro/E系统调用。最终形成了平行分度凸轮机构的CAD/CAM系统,本系统实现了子系统之间的信息传递和信息共享,提高了平行分度凸轮设计和加工的集成化、自动化的程度,从而为平行分度凸轮机构的设计、制造及性能研究提供了一种快捷的软件平台。更多还原

【Abstract】 It follows from the comparison of many kinds of CAD/CAM software and the analysis of characteristics on parallel indexing cam mechanism that Pro/E is the most reasonable software for developing platform. Developing environment was established by means of Pro/E, Pro/TOOLKIT, Pro/Program and Visual C++.The coordinate equation of parallel indexing cam profile was derived by means of relative motion method and isometric curve theory. Cam profile formed by enveloped curve fully and that formed by enveloped curve partially have been analyzed. Conditions of non-interference are: (1) Curvature radius is not less than roller’s radius if curvature center of definite point is on the out side of profile. (2) Derived number of indexing profile is continuous.Conditions of continuous transmission for parallel indexing cam mechanism are: (1) There is at least 1 roller engaging with each cam disc at any time. (2) There is at least 1 roller in cam driving zone.Pressure angle equation was educed. According to the analysis of pressure angle for parallel indexing cam mechanism, the greater the radius of roller rr , the greater the pressure angle is. The greater the radius of rollers distributed circle rd , the smaller the pressure angle is. The smaller the addendum radius of cam R a, the smaller the value range of pressure angle.It follows from the analysis of kinemics that angular displacementθand angular speedωof Gutman are similar with shoes of quasi-cosine. The angular acceleration of Gutman is smoothly continuous. There are breaks for angular acceleration of quasi-cosine. That is distinct between two kinds of driving rule.During dynamics analysis, parallel indexing cam mechanism has been simplified as input subsystem and output subsystem. Engaging point is the boundary of the subsystems, which are coupled by displacement and forces exerted each other at this point. Input system and output system were simplified as one-freedom system respectively, which consists of equivalent moment of inertia, equivalent stiffness and equivalent damp. Dynamic response equations have been established. Evaluation formula is presented based on numerical computation theory. Dynamic simulation of mechanism system has been done. It follows from dynamic analysis that the influence of input speed on maximum swing is too little to take into account. Input speed influences the shape of vibration output graph because of the change of dynamic load frequency. The smaller the stroke angle, the more violent the vibration is. The maximum swing of quasi-cosine is less than that of Gutman. At the end of Gutman indexing, vibration shanks much more sharply than the case of quasi-cosine.The architecture of CAD/CAM system has been established. Function for every module das been designed and implemented. During the development of CAD module, forming process of cam profile and computing of data for cam profile were discussed in details. The frame of CAD subsystem and the implementation of part modeling and assembly were introduced.During the development of CAM module, the CAM subsystem was implemented by means of dynamic link libraries program based on database Access and VC++. It was loaded in menu form for Pro/E system to be called back.Finally, the system CAD/CAM for parallel indexing cam mechanism was established. The implementation of information transfer and information sharing between the subsystems can improve the degree of integration and automation on design and manufacture for parallel indexing cam. So, the developed CAD/CAM system is a excellent software platform for parallel indexing cam mechanism desin, manufacturing and dynamic behavior research.更多还原