【作者】 程金石；

【导师】 刘健；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 本论文提出了用于实现平行轴间分度运动的管状面槽式凸轮分度机构,并对其理论与技术进行了较为系统的研究。因机构以钢珠为滚动体,对应的凸轮廓面为槽式管状曲面,故命名为管状面槽式凸轮分度机构。该机构具有压力角情况良好、分度数范围大、适应性强、制造容易等优点,可以广泛应用于平行轴分度运动场合。论文以瞬心线和旋轮线为研究工具,将瞬心线视为机构运动的几何表征,凸轮型线视为瞬心线相对运动时钢珠中心发生的旋轮线,并借助瞬心线建立凸轮型线与速比曲线的关系。为此,论文结合凸轮分度机构对旋轮线、瞬心线、速比曲线及其关系进行了研究。归纳了旋轮线的几何学性质和几何形态与发生点位置的关系。研究了曲线的奇点特性,包括切矢方向、奇点阶数和导出曲率等。在此基础上,讨论了旋轮线上奇点的产生条件及性态,得出了不同导出曲率情形的瞬心线条件。分析了含奇点的直线旋轮线的位置特点和瞬心线条件。结合运动特点分析了凸轮分度机构的速比条件及瞬心线特征。针对从动旋轮线在奇点处导出曲率为零及在奇点附近为直线两种情形,分别给出了奇点变异法和拼接法两种速比曲线设计方法,作为奇点应用的实现条件。以上述理论为指导,针对凸轮分度机构的基本要求并考虑到现有同类机构的技术局限,论文提出了管状面槽式凸轮分度机构的基本构思。根据啮合副的组成性质,将机构分为正作用式、逆作用式和双作用式三种类型。其中正作用式机构利用多钢珠同时工作有效减小了啮合压力角和工作面层数。逆作用式和双作用式机构利用奇点获得了优良的压力角特性和驱动特性,并扩大了机构的分度数范围。论文借助点与线的啮合模型,对三种类型机构的基本原理和主要特性进行了分析。在此基础上,研究了机构的主要性能,包括钢珠与凸轮廓面的啮合特性、点啮合化的实施方式和参数、钢珠的受力和运动状态、机构对误差的敏度等。最后,论文讨论了机构设计和制造的有关问题。对逆作用式机构的原型机进行了设计、制造及原理性试验研究。试验结果证实了机构原理上的正确性和技术上的可行性,达到了预期目标。更多还原

【Abstract】 The dissertation proposes a new type of indexing cam mechanisms to realize indexing motion between parallel shafts. For adopting tuber surface groove cams the mechanisms are named the tuber surface groove cam indexing mechanisms.The less pressure angle, wide indexing range, good adaptability and manufacturability make the mechanisms wide applied in the occasions of parallel indexing.For the dissertation regards the cam mould curves as cycloids, denotes the shafts motion by centrodes, and determines the relation between cam mould curve and speed-ratio curve by centrodes, the cycloid, centrodes and speed-ratio curve of cam indexing mechanisms are studied. The geometry and configuration of cycloid with different position of generant are summarized. The characteristics of singular point on curve are analyzed, including its tangent vector, order and deriving curvature. On the basis of it, the existing conditions and characteristics of singular point on cycloid are discussed, and the relation between the deriving curvature of singular point and centrodes are concluded. The centrodes conditions and characters of linear cycloid are analyzed too. Based on the motion characters, the speed-ratio curve and centrodes of indexing cam mechanisms are analyzed. To realize the zero deriving curvature of singular point and linear cycloid, two methods of designing speed-ratio curve are introduced, which contributes the application of singular point in the proposed mechanisms.On the basis of above study works as well as considerations of the demands of indexing mechanisms and the shortages of the traditional parallel indexing cam mechanisms, the dissertation constructs the tuber surface groove cam indexing mechanisms. According the compose of meshing pairs the mechanisms are divided three kinds being named the normal-action, the inverse-action and the double-action tuber surface groove cam indexing mechanisms successively. The first mechanisms decrease pressure angle and reduce meshing layer by more than three balls meshing with the cam at any moment. The second and the third mechanisms have the same distinctive character that there are singular points on the cam mould curve and the curve is line near the points, which contributes the excellent pressure angle, the large loadability and the wide indexing range of the mechanisms. The principle and feasibility of these mechanisms are discussed. The main properties are analyzed including the meshing characteristics of steel ball and cam surface, the method and parameters of mismatch treatment, the force and motion analysis of steel balls, and the sensitivity of the mechanisms to errors.Finally, the dissertation discusses the problems about the designing and manufacturing of the mechanisms, designs and produces the prototype machine of inverse-action tuber surface cam indexing mechanisms. The running test of the prototype machine shows that the proposed mechanisms are correct in principle, realizable in techniques, and the anticipative purposes are achieved.更多还原