Research On Principle And Technology Of Tuber Surface Groove Cam Indexing Mechanisms

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.