Research On Point-meshing Elastic Roller-gear Cam Mechanism In Predictable Control

The existing problem of the traditional RCM (roller-gear cam mechanisim) and the characteristic of new PGRCM (point gearing roller-gear cam mechanisim) are analyzed in the paper. On the basis of the integrated study on the research status of RCM at home and aboard, the RCM in automatic machinery including packing machinery is taken as the research object, the improvement of precision and moving stability is taken as the purpose. Broken throuth the hypothesis that cam and other components all are stiff in the traditional mechanism, PGRCM is performed the systemic research on the basis of point gearing theory and elastic mechanics finite element theory in considering the premise that the point gearing between roller-gear cam and roller causes minute elastic touch distortion. Furtermore, the design method, application development and manufacturing equipment of roller-gear cam are summarized.The basic theroy of roller-gear cam working camber of PGRCM is founded in this paper, on the basis of line gearing characteristic analysis, the point gearing of RCM is realized by the method of roller shape modification, the concept of equivalent roller is introduced; the universal machematical model of RCM and the profile equation of roller-gearing cam are founded. The problem of envoloping method of working camber of cam is mainly solved, which provides the theory basis for the analysis of machinism surface and the manufacture of roller-gearing cam.For different types of RCM and rollers, the generally parameterized mathematical pattern of roller surface is proposed, and all kinds of simple roller surface are integrated in the ball-conical roller model, thus the basic mathematical pattern is provided for active design of roller surface, which also provides theoretical foundaion for the analysis of optimum surface fitting, thus the practical shape modification of rollers is theorized and quantitated.Based on the analysis of load and stress distribution, Mating relations and contact state of PGRCM, the problems of pressure angle, curvature and contact stress of PGRCM are studied and the calculation formulas are deduced. The contact models of the elastic finite element meshing between cam and roller are established, and the variation law of contact stress and contact elasticity deformation are Obtained. Compared with line gearing, the effect of curvature on gearing and contact deformation and difference are analyzed and the curvature fitting Parameters between cam and roller surface under the premise of keeping appropriate deformation and contact field are obtained.The key problems of the analysis of gearing field, the effect analysis of the surface structure parameter of cam and roller on gearing capability, the quantity of the optimum gearing position and the optimum elastic deformation, the construction of the optimum roller surface and the guarantee of load-carring ability are studied, and the precontrol method of gearing field and gearing capability are formed in this paper.On the above studies, the design method and procedure of the precontrollable PGRCM are summarized, and the design and application of thin less-support NC rotary table which applies the PGRCM with the special structure and the lifting indexing device with mechanical arm appling the PGRCM, the feasibility of the theory and method is verified,and a strong guarantee is provided for the practical application of this technology by the development and design of the special four-axis double revolving NC milling machine for the manufacture of roller-gear cam.