【作者】 茅健；

【导师】 吉晓民；

【作者基本信息】 西安理工大学 ， 机械设计与理论， 2002， 硕士

【摘要】 本文从CAD／CAM集成技术的角度较为全面地研究了共轭凸轮的设计及加工问题，开发了一套共轭凸轮的CAD／CAM集成软件系统。文中研究了从动件运动规律的拼接问题，得到了具有复杂廓线凸轮的运动规律，推导了共轭凸轮廓线理论坐标的计算公式；提出了一种求凸轮实际廓线坐标的简便方法；总结了各种情况下圆弧插补的形式，提出了计算法和图形处理法两种圆弧插补的方法；引入了插补误差的概念，提出了大跨距圆弧插补的方法；开发了数控加工代码生成模块，可自动生成数控加工的NC代码。 论文各部分的主要内容如下： 首先，论文分析了现有的求共轭凸轮机构理论廓线坐标的方法，推导出了相对简便的求理论廓线坐标的计算公式。对于从动件不同段运动规律的拼接作了研究，能够设计出具有较好特性的复杂廓线凸轮的运动规律，并用VC⁺⁺6.0编制了计算共轭凸轮理论廓线的程序。 其次，求实际廓线坐标时，通过对AutoCAD进行二次开发，文中提出了一种新的方法，省去了复杂的数学计算过程。主要是利用AutoLISP语言来提取实际廓线的坐标数据，开发了相应的菜单及其对话框。这样不仅能够自动生成凸轮的实际廓线，而且可以非常直观地判断出廓线是否有变尖或失真现象。 再次，论文深入地分析了圆弧插补的方法，归纳出了圆弧插补时的各种计算公式，提出了计算法和图形处理法两种圆弧插补的方法，并引入了插补误差来进行大跨距插补，减少了圆弧的段数；提出了判断顺逆圆的判据，开发了相应的计算程序及自动生成NC代码的程序。 最后，论文以某共轭凸轮机构为例，详细介绍了在本文所开发的软件系统中进行共轭凸轮的设计、凸轮廓线的圆弧插补及NC代码生成、凸轮廓线的加工模拟等操作过程，证明了所开发软件系统的可靠性和实用性。更多还原

【Abstract】 Based on the CAD/ CAM integrated technique, the design and manufacture of conjugate cam are studied and a CAD/ CAM integrated software system is developed. The combination of different follower’s movement curves is discussed and a combined movement curve of the follower is generated for the conjugate cam with complex profile. The calculating formula is given for the theoretical profile of conjugate cam and a simple method is presented for the generation of the actual profile coordinates. Taking the manufacture of the cam into account some methods for the representation of cam profile with different jointed arcs are summarized. Two methods, named Calculation Method and Drawing Method respectively, are presented. Based upon the consideration of the interpolation-error, the arc-interpolation with multi-points (called Big Spaced Arc-interpolation Method) is put forward so that the cam profile can be represented with fewer arc segments. A module for NC codes generation is developed and the NC codes for cam manufacture can be generated automatically.The main points of the paper are as follows:Firstly, the current methods for the theoretical profile coordinates of conjugate cam are analyzed and the calculation formula is given for the theoretical profile coordinates. The combination of different follower’s movement curves is studied and a combined movement curve of the follower with better.performance can be generated for the conjugate cam with complex profile. A software written by VC++6.0 is developed to calculate the coordinates on the theoretical profile of conjugate cam.For the calculation of the actual profile coordinates, the paper presents a new method based on the development to AutoCAD. This does not need complicated mathematical calculation but gets the coordinates on the actual profile of the cam simply by a program written with AutoLISP. The related menus and dialogue boxes are developed. By this way the data and the drawing of the cam actual profile can be generated automatically, and whether the profile is correct or not can been found very directly in the manner of drawing as well.The methods for arc-interpolation are analyzed in the paper and the calculation formula are given for arc-interpolation under various conditions. Calculation Method and Drawing Method are presented for arc-interpolation. In order to decrease the segments ofthe arcs, the Big Spaced Arc-interpolation Method is put forward under the consideration of interpolation error. The judging criterion is given for clockwise arc and counter-clockwise arc. The modules are developed for calculating the parameters of the arcs and automatically generating NC codes.Taking a certain conjugate cam as an example, the paper introduced the processes and the operation in the system from the design, arc-interpolation to generation of NC codes and cutter location simulation for the cam profile. The reliability and practicability of the software system are proved.更多还原