【作者】 匡正；

【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】 弧面凸轮机构能够实现多种复杂运动形式,已在许多自动机械中广泛应用。作为其关键部件,弧面凸轮的加工精度和表面质量直接决定了该机构的工作性能和品质。目前国内外弧面凸轮加工主要采用数控加工方法,但我国精密弧面凸轮的研发能力与国外相比还有较大差距。究其原因主要是弧面凸轮工作廓面结构复杂,加工难度大,特别是数控编程仅基于纯几何的刀具轨迹规划方法未能充分考虑机床误差、工装误差、刀具误差等多项原始误差的综合影响,弧面凸轮廓面误差无法实现科学预测和有效控制。如何揭示机床误差、工装误差、刀具误差等多项原始误差对弧面凸轮加工精度的综合影响,实现弧面凸轮廓面误差高效、科学预测和有效控制是精密弧面凸轮机构产品研发中的一项重要课题。因此,迫切亟待开展弧面凸轮廓面误差系统分析与预测研究,为弧面凸轮加工刀轨优化和误差有效控制提供科学依据。为此,本文利用多体系统误差建模理论、弧面凸轮机构空间啮合原理、Matlab等手段,探索弧面凸轮廓面误差综合模型,深入分析各原始误差对弧面凸轮廓面加工精度的影响规律。具体研究工作如下:1)综述了弧面凸轮加工误差分析、多体系统理论在切削加工误差分析中的应用和数控机床几何误差建模的研究现状,并推导了弧面凸轮理论廓面方程,奠定了后续研究基础。2)分析了机床空间几何误差因素。针对DMU80T五轴立式镗铣加工中心,在分析机床结构特点和运动几何误差的基础上,建立了该数控机床的空间几何误差模型。3)建立了弧面凸轮廓面误差综合模型。根据范成法和单侧面加工方法并结合具体机床的结构和配置条件,以多体系统误差建模理论和弧面凸轮机构空间啮合原理为基础,分别推导出范成法加工和单侧面加工的包含机床各轴运动误差在内的弧面凸轮误差廓面方程,同时给出了弧面凸轮廓面法向误差的定义、计算方法和计算过程。4)进行实例仿真分析。基于上述研究工作,利用Matlab编制了弧面凸轮廓面多轴数控加工误差综合分析程序,实例仿真计算结果反映出各原始误差对弧面凸轮廓面误差的综合影响规律。综上,本文的研究为弧面凸轮廓面误差高效、科学预测提供了理论依据,为弧面凸轮加工刀轨优化和基于误差补偿的高效精密加工奠定了基础。更多还原

【Abstract】 Globoidal cam mechanism has been extensively applied in many automatic machines for its ability of achieving many complex moving forms. As the key parts, the machining precision and surface quality of globoidal cam directly determine the working performance and quality of this mechanism. At present, the NC machining is the main processing method for globoidal cam at home and abroad. Compared with abroad, there is still a large gap in the R&D capabilities about precise globoidal cam. The main causes are that the structure of globoidal cam working profiles are complex and difficult to machining, especially the NC programs are only based on the simple geometry tool path strategy and without considering the synthetic influence of other original errors, such as machine tool error, clamping error, tool error, etc. The profile machining error of globoidal cam is unable to realize scientific prediction and available control. How to reveal the synthetic influence of original errors on globoidal cam machining precision, realize efficient-scientific prediction and available control to profile machining error of globoidal cam have become a key task in the R&D about precision globoidal cam mechanisms. Thus, it is urgent necessary to do some researches on systematic analysis and prediction for globoidal cam profile error to provide scientific basis for tool path optimization and error effective-control. Therefore, the profile error synthetic model of globoidal cam has been built in this paper with the help of multi-body error-modeling theory, meshing theory of spatial mechanisms and Matlab tool, etc.. And the influence law of each original error on profile machining precision of globoidal cam has been deeply analyzed. The main works in this thesis can be concluded as the following:1) This paper provides an overview for the machining error analysis about the globoidal cam, the application of multi-body system to machining error analysis and the geometric error modeling of NC machine tool. Then, the theoretical profile equation is deduced and the basis is established for the subsequent study.2) The machine tool spatial geometric error factors are analyzed. Aimming at the DMU80T (a five-axis vertical boring-milling machining center), the spatial geometric error model of this machining center is built after the structure and kinematic-geometric errors being analyzed.3) The profile error synthetic model of globoidal cam is built. According to the generation method and one-side machining method, and combination with the structure and configure of the machine tool , the error profile equations of globoidal cam including machine tools’kinematic errors are deduced for the generation method and one-side machining method respectively based on the multi-body error-modeling theory and spatial meshing theory of globoidal cam mechanisms. Simultaneously, the normal error definition, calculation method and calculation process of globoidal cam are given.4) The analysis of example simulation is done. Based on the above research works, the profile error synthetic analysis program of multi-axis NC machining for globoidal cam is compiled by using Matlab tool. The calculation results of example simulation reflect the synthetic influence law of each original error on globoidal cam profile machining error.In conclusion, the researches in this paper provide a theoretical basis for the efficient-scientific prediction of the profile error of globoidal cam, and establish basis for the machining tool path optimization and high efficient & precision machining globoidal cam based on error compensation.更多还原