Research On Digital Design Method Of Pure Rolling Noncircular Gear Pair

Non-circular gear pair is a kind of mechanism which can realize variable transmission ratio.It can be designed artificially according to the working requirements.It inherits the advantages of cylindrical gear transmission and has better meshing performance,stable transmission and low noise compared with other variable transmission ratio mechanisms.Helical non-circular gear has the advantages of straight non-circular gear and helical cylindrical gear,which increases the contact ratio of non-circular gear pair and enhances the bearing capacity.Moreover,there is no impact in the process of gear meshing in and out,and the transmission is more stable.However,the non-circular gear pair designed by the traditional design method,like all kinds of cylindrical gear transmission process,there is a relative sliding between the meshing tooth surfaces in the transmission process,which makes the tooth surface prone to wear,glue or pitting.In order to reduce the negative impact of non-circular gear caused by relative sliding in the transmission process,this paper will study a new non-circular gear pair-pure rolling point contact non-circular gear pair.In the meshing transmission process of pure rolling non-circular gear pair,only the nodes are engaged.There is no relative sliding between the meshing tooth profiles,and the pure rolling contact is always maintained.Because of the superior transmission performance of pure rolling non-circular gear pair,the application prospect is broad.The main research contents of this paper are as follows:（1）In the design theory of pure rolling non-circular gear: According to the design requirements of non-circular gear,the pitch curve design method and verification conditions of non-circular gears were studied.Based on the existing pure rolling theory and non-circular gear transmission theory,the conceptual model of pure rolling non-circular gear pair transmission is further studied.（2）In pure rolling non-circular gear pair pure rolling tooth profile design method: In this paper,starting from the principle of non-circular gear meshing,the mathematical model of noncircular active gear tooth profile is established by gear cutter.Then based on the mathematical model of non-circular active gear tooth profile,the calculation method of pure rolling meshing point is deduced according to the constraint condition of pure rolling point.Finally,according to the pure rolling transmission principle of pure rolling non-circular gear pair,the tooth profile mathematical model of pure rolling non-circular driven gear is established.On this basis,the design method of pure rolling tooth profile of non-circular gear pair proposed in this paper is summarized,and the point cloud generation method and algorithm flow of pure rolling tooth profile are formed.The design method of pure rolling tooth profile of non-circular gear pair is completed,which lays the foundation for the accurate solution of tooth profile point of pure rolling non-circular gear pair.（3）In terms of transmission performance and meshing characteristics of pure rolling noncircular gear pair: Aiming at the design method of pure rolling non-circular gear tooth profile proposed in this paper,the MATLAB software is used to solve the tooth profile point cloud of pure rolling non-circular gear pair.The three-dimensional solid model of pure rolling noncircular gear pair is established by CATIA three-dimensional modeling software.The solid model is loaded and simulated by ABAQUS software.The transmission ratio curve obtained by simulation analysis is compared with the theoretical transmission ratio curve.And verify the position of pure rolling meshing point.Based on the five-axis CNC machining center,the pure rolling non-circular gear pair is processed.The test platform of pure rolling non-circular gear pair is built,and the transmission ratio is tested.Finally,the test data are analyzed to verify the effectiveness of the design method.