弧面凸轮机构制造误差及曲面特性研究

发布时间：2018-04-24 12:48

本文选题：弧面凸轮机构 + 微分几何　；参考：《北京工业大学》2016年博士论文

【摘要】：弧面凸轮机构是一种间歇分度传动机构,由于其结构紧凑、工作可靠、承载能力大等优点广泛应用于食品机械、包装机械、烟草机械及加工中心自动换刀装置(ATC)中。本文研究的弧面凸轮机构,由于其运动关系复杂,弧面凸轮廓面难于加工,目前我国对于高档弧面凸轮机构(也即自动换刀装置)还没有完全自主生产能力,大部分依赖进口。为了提升整体制造能力,完全掌握其核心制造技术,迫切需要对弧面凸轮机构进行系统深入的理论研究,为开展全面生产制造提供理论基础。首先,论文对四轴双联动弧面凸轮专用加工机床加工出的弧面凸轮轮廓误差进行了分析。基于微分几何和啮合理论,充分考虑了弧面凸轮专用加工机床各旋转轴误差、相对位置误差以及线位移误差等,推导了弧面凸轮廓面误差的数学模型,通过引用影响因子的概念分析了机床误差对弧面凸轮廓面加工误差的影响。为设计加工弧面凸轮专用机床提供理论指导,提出了既考虑成本又考虑加工容易程度的加工容易度模型,以最大加工容易度为目标,以弧面凸轮廓面的加工精度为限制条件,并充分考虑加工工艺的约束条件等,建立了弧面凸轮专用加工机床的公差分配模型。通过优化设计方法,得到了机床的公差优化设计结果,为弧面凸轮专用加工机床的公差设计提供了参考。接着,针对弧面凸轮凸脊较薄的问题,开展了弧面凸轮凸脊厚度计算的研究。运用微分几何中的测地线理论,提出了弧面凸轮凸脊厚度的计算方法,并基于微分几何和啮合原理,推导了弧面凸轮凸脊厚度的解析表达式。此外,还研究了弧面凸轮廓面的接触线、凸脊两侧廓面与参考圆环面的交线以及参考圆环面的测地线。通过VC++软件对以上参数进行了数值计算,并利用Creo软件进行了三维仿真。通过不同运动规律曲线的比较,研究了弧面凸轮脊厚的影响因素,为后续弧面凸轮机构运动规律的选取以及弧面凸轮强度和刚度等的分析奠定了基础。其次,研究了弧面凸轮廓面的曲面特性。首先研究了弧面凸轮廓面的第一基本型、第二基本型和第三基本型,在此基础上推导并计算了弧面凸轮廓面的主曲率、主方向、高斯曲率、渐近方向等参数。然后依据弧面凸轮机构的不同运动区间,对弧面凸轮曲面的局部几何形状进行了分类研究,并通过VC++软件计算后利用Creo软件对弧面凸轮廓面的几何参数进行了三维仿真。最后,对弧面凸轮的直纹面特性进行了研究。为了得到精确的计算结果,计算并仿真了弧面凸轮廓面的渐近曲线,而且提出应用渐近曲线的曲率来判别弧面凸轮廓面是否为直纹面。分析结果表明弧面凸轮廓面为非直纹面,此部分研究成果为弧面凸轮加工工艺的选取提供了理论参考。再次,系统全面地提出了研究弧面凸轮机构啮合曲面的几何特征的方法。总结了弧面凸轮廓面Dupin标线的计算公式,依据不同的曲面特征点计算并绘出了弧面凸轮与从动滚子廓面的Dupin标线。计算了弧面凸轮与从动滚子在啮合点处沿各个方向相对法曲率的特征曲线,并对不同啮合点处的相对法曲率特征曲线进行了比较。基于Dupin标线,应用Radzevich的曲面一致性理论分析了弧面凸轮机构啮合曲面的接触几何特征。结合弧面凸轮与从动滚子的啮合特点,首次研究了马鞍面与瓦状面啮合的曲面一致率标线,同时为两啮合曲面干涉提出了新的判别方法。该部分研究内容将对以后啮合曲面接触强度和接触应力的研究提供有力的理论依据。最后,对弧面凸轮廓面误差及刀库弧面凸轮机构刀具翻转定位精度开展了实验研究。通过使用三坐标测量机对设计的弧面凸轮制造专机制造的弧面凸轮廓面误差进行了检测,并给出了详细的检测步骤和测量结果。开发了刀库中自动换刀装置刀具翻转定位精度的检测平台,研究了检测原理及方法,为工厂提供了动态检测刀具翻转定位精度的方案及检测方法。
[Abstract]:The globoidal cam mechanism is a kind of intermittent transmission mechanism. It is widely used in food machinery, packaging machinery, tobacco machinery and machining center automatic knife exchange device (ATC) because of its compact structure, reliable work and large bearing capacity. The arc surface cam mechanism studied in this paper is difficult to be machined because of its complex motion relations. At present, our country has not fully independent production capacity for the high grade camber cam mechanism (also that is automatic knife exchange device). Most of them depend on the import. In order to improve the overall manufacturing capability and master the core manufacturing technology completely, the theoretical research on the arc surface cam mechanism is urgently needed to provide the theoretical basis for the comprehensive production and manufacture. First, the paper analyzes the profile error of the arc surface cam machined by the four axis double linkage arc surface cam machine tool. Based on the differential geometry and meshing theory, the error of the rotation axis, relative position error and line displacement error of the arc surface cam are fully considered, and the error number of the arc surface cam profile is deduced. The influence of the machine error on the machining error of the arc surface cam profile is analyzed by the concept of the influence factor, and the theoretical guidance is provided for the special machine tool for the design and processing of the camper cam. The machining precision is limited and the constraint conditions of processing technology are taken into full consideration. The tolerance distribution model of the arc surface cam special machining machine is set up. The optimum design result of the tolerance of the machine tool is obtained by the optimization design method, and the reference for the tolerance design of the arc surface cam special machining machine is provided. Then, the camber cam convex ridge is used. The calculation of the thickness of the convex ridge of the globoidal cam is put forward by using the geodesic theory in differential geometry. Based on the differential geometry and meshing principle, the analytic expression of the thickness of the convex ridge of the camper cam is derived, and the contact line and the convex ridge of the curved cam profile are also studied. The intersection of the two sides of the surface and the reference circle ring and the geodesic reference circular ring. Through the VC++ software, the above parameters are calculated, and the three-dimensional simulation is carried out with the Creo software. The influence factors of the ridge thickness of the camper cam are studied by the comparison of the curves of different motion laws, which can be used for the selection of the motion law of the following cam mechanism. As well as the foundation for the analysis of the intensity and stiffness of the globoidal cam. Secondly, the surface characteristics of the arc surface cam profile are studied. First, the first basic, second basic and third basic profiles of the arc surface cam profile are studied. On this basis, the main curvature, the main direction, the Gauss curvature, the asymptotic direction, etc. of the arc surface cam profile are derived and calculated. And then according to the different motion intervals of the camboface cam mechanism, the local geometry of the curved surface cam surface is classified and studied. The geometric parameters of the curved surface cam profile are simulated with the software Creo software by VC++ software. Finally, the straight surface characteristics of the camper cam are studied. The asymptotic curve of the arc surface cam profile is calculated and simulated, and the curvature of the asymptotic curve is applied to determine whether the curved surface of the camper cam is a straight face. The analysis results show that the arc surface cam profile is non straight surface. The research results provide a theoretical reference for the selection of the machining process of the arc cam. The method to study the geometric features of the meshing surface of the camper cam mechanism is put forward comprehensively. The calculation formula of the Dupin line of the arc surface cam profile is summed up, and the Dupin marking of the curved surface cam and the driven roller profile surface is drawn according to the different feature points of the curved surface. The characteristic curves of normal curvature are compared, and the relative normal curvature characteristic curves at different meshing points are compared. Based on the Dupin line, the contact geometry characteristics of the meshing surface of the camber cam mechanism are analyzed by using the surface conformance theory of Radzevich. The saddle surface and the tile shape are first studied in the light of the meshing characteristics of the arc surface cam and the driven roller. At the same time, a new discriminant method is proposed for the two meshing surface interference. This part will provide a powerful theoretical basis for the study of contact strength and contact stress of the meshing surface. Finally, the accuracy of the arc surface cam profile error and the tool turnover positioning accuracy of the cutter base cam mechanism is carried out. The three coordinate measuring machine is used to detect the profile error of the arc surface cam made by the designed arc surface cam manufacturing machine, and the detailed detection steps and results are given. The detection platform for the positioning accuracy of the tool turnover in the automatic knife exchange device is developed, and the principle and method of the detection are studied. Dynamic detection of tool turnover positioning accuracy and detection method.

【学位授予单位】：北京工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TH112.2

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