Research On The Parametric Designing And Virtual Machining Technology Of Limacon Gear

Gear is mainly used for transferring the gyratory motion between two shafts as one of commonly used transmission mechanisms in mechanical transmission. At present, the most widely used part in gear transmission is traditional circular gear.With the development of modern industry, circular gear can’t meet transmission available needs, so non-circular gear emerge as the times require.Limacon gear, which pitch curve changes according to cosine law, is a new kind of non-circular gears, and it has many advantages that could not be replaced by other non-circular gear mechanisms. Therefor, it is necessary to make a further research to its parametric design and its numerical control machining for its design cycle shortening, processing accuracy improving and range of application broadening.Based on it, took limacon gear as the research object in this thesis, the parametric design and modeling were done to its pitch curve by the analysis on the meshing theory of limacon gear pair,besides the NC program was programmed combining form-grinding wheel theory with machining processing analysis of limacon gear, the accuracy of program and the feasibility of process scheme were verified by further virtual simulation.Firstly, the curvature radius, closeness of pitch curve, its concavity and convexity was analyzed based on the mathematical model of the pitch curve of limacon gear, parametric modeling was done to its pitch curve by Matlab GUI, which realized the real-time show of its pitch curves of limacon gear pair and its corresponding transmission ratio curve, the three-dimensional modeling of its tooth profile was built according to “conversion method of tooth profile”.Secondly, according to the problem of grinding of limacon gear, the grinding method of limacon gear by using form-grinding wheel was put forward; its tool path,coordinate system, security plane were confirmed, and its cutter path was programmed, which was used for generating G machining code after post-processing;tool path was checked by the tool path checking function of UG, and the tool path check log was generated.Finally, in order to verify the reasonableness of processing scheme and the correctness of program, the grinding of limacon gear was simulated by VERICUT software after gear grinding machine built, parameter of machining setting, coordinate system of kinematic axis analysis and controlling system uploading and program adding, the problem of overcut and undercut were analyzed; the solution was putforward after the analysis on the common defects of form-grinding of limacon gear.According to the above research, the parametric design system of pitch curves of limacon gear pair was built, the feasibility of form-grinding in machining limacon gear was verified, which provide a complete theoretical basis for its grinding process,and it also has certain reference value for the design and simulated machining of general non-circular gears, further circular gears.