【作者】 刘杰梅；

【导师】 胡自化；

【作者基本信息】 湘潭大学 ， 机械制造及其自动化， 2011， 硕士

【摘要】 以弧面凸轮为核心件的传动机构具有精度高、承载扭矩大、结构紧凑、使用寿命长等特点,已在许多自动机械中广泛应用。目前国内外对弧面凸轮主要采用数控加工方法,很大程度上提高了弧面凸轮加工精度和加工效率。但国产弧面凸轮式传动机构产品的性能与国外同规格产品仍然存在较大差距,市场的占有率还很低。究其原因是弧面凸轮工作廓面为不可展螺旋曲面,其加工与检测对精密数控加工中心、三坐标测量机等昂贵仪器设备严重依赖,而国内弧面凸轮的制造与检测手段不健全,整体水平还很滞后,严重制约了国产弧面凸轮式传动机构产品的高精、高效开发和推广应用。如何降低对三坐标测量机的严重依赖性,实现弧面凸轮廓面加工误差高效、低成本测量是弧面凸轮式传动机构产品制造中的一项重要课题。因此,迫切亟待深入研究弧面凸轮廓面加工误差高效虚拟测量技术,以弥补目前三坐标测量复杂曲面的诸多不足。为此,本文利用虚拟测量原理、弧面凸轮空间啮合理论、UG及其开发工具、VC++等手段,探索弧面凸轮廓面加工误差的虚拟测量方法、模型,进行测量软件开发和实例应用,具体研究工作如下:1)综述了弧面凸轮数控加工工艺、数控加工误差测量以及虚拟测量技术的发展现状,分析了虚拟测量技术在弧面凸轮加工误差检测方面的发展趋势;根据弧面凸轮空间啮合理论,推导了弧面凸轮的理论廓面方程,奠定了后续研究基础。2)提出了基于虚拟测量原理的弧面凸轮加工误差虚拟测量方法,基于虚拟测量原理,以数控加工仿真模型为虚拟测量对象,利用弧面凸轮理论曲面方程规划虚拟测头的测量离散位置,通过几何干涉判断分析测头与被测加工曲面的空间几何位置关系,依据干涉程度求解加工误差。3)依据虚拟测量模型,利用UG平台及其二次开发工具和VC++开发了弧面凸轮加工误差虚拟测量软件,运用VERCUT仿真进行弧面凸轮虚拟测头测量轨迹验证,测量软件实现了与UG系统无缝集成,为弧面凸轮虚拟设计、制造与测量提供了CAD/CAM/CAT有效平台支撑。4)基于以上研究进行实例分析,分别对范成法和单侧面偏置法加工的弧面凸轮廓面加工误差进行虚拟测量,实例虚拟测量值与文献理论预报值完全吻合,表明提出的方法正确、建立的模型有效、开发的软件可信。综上,本文的研究为弧面凸轮廓面加工误差实现高效、低成本测量提供了有效解决方案,为拓展虚拟测量技术在复杂曲面加工中的应用示范奠定了理论基础。更多还原

【Abstract】 The actuating mechanism with globoidal cam as the core pieces has the advantages of high precision, heavy load torque, compact structure, long service life, which has been widely used in the automation machinery. Presently, the CNC machining method is the main machining method for globoidal cam at home and abroad ,and this greatly improves the machining precision and efficiency. Compared with abroad, there is still a large gap in the wheeled actuating mechanism of the globoidal cam, and the market share is still very low. The main cause is that the working profile of globoidal cam as a skew helical surface,its machining and measurement heavily rely on some expensive equipments such as precise CNC machining center, Coordinate Measuring Machines(CMMs), the manufacturing level and measuring methods are unsound and the overall level are fairly backward at home. Thus it severely restricts the precision-efficient development and application of globoidal cam at home. How to reduce the severe dependence of the CMMs, achieve the efficient and low-cost measurement for the machining error of globoidal cam is an important issue in the machining of globoidal cam mechanism. Therefore, it is urgent necessary to develop an efficient virtual measuring technique for the profile machining error of the globoidal cam to cover the shortage of complex surfaces measurement by three-coordinates measuring machine. Therefore, based on the virtual measuring principle and the meshing theory of the globoidal cam, this paper has explored a virtual measurement method and model for the machining error of the globoidal cam with the help of UG and its development tools, VC++ , etc, and developed some virtual measurement software, analyzed some examples. Specific studies are as follows:1) Review the development of the CNC machining technology of the globoidal cam, the measuring technology for CNC machining errors and virtual measuring technology. Then, analyze the developing trend of the virtual measurement technology in CNC machining technology of the globoidal cam. Finally, the profile equation of the globoidal cam is derived according to the meshing theory and the basis is established for the subsequent study.2) Based on the virtual measuring principle and taking the CNC machining simulation model as the virtual measure object, the virtual measuring method for machining error of globoidal cam has been proposed. The discrete position of the virtual gauge head is planed by the theoretical profile equation of globoidal cam and the geometry relationship between the gauge head and the measured surface is judged by the geometric interference function, and finally solving the processing error by the interference level. 3) According to the virtual measuring model, the virtual measuring software is developed by UG secondary development tools and VC++ based on UG platform. Then, the measurement trace of globoidal cam’s virtual gauge head is verified by VERCUT. This measuring software achieves seamless integration with the UG platform which provides an effective CAD/CAM/CAT platform for the virtual design, virtual manufacturing and virtual measurement of the globoidal cam.4) Based on the above research, the example analysis is done. The machining simulation models processed by the generating method and the one-side milling method are separately measured by the virtual measurement software, and the actual value of virtual measurement is consistent with the theoretical predication value. Thus it reflect the proposed method is correct, the established model is effective and the developed software is credibleTo sum up, this paper not only provides some effective solutions to achieve efficient and low-cost measurement for the processing error of globoidal cam, but also lays the theoretical foundation to expand the application of the virtual measurement technology in the processing of complex surface.更多还原