| Cycloid-pin gear planetary transmission is one of the core components of robot RV reducer.It has many advantages,such as large meshing teeth,significant error average effect,large reduction ratio range,good transmission stability and long service life.Therefore,it is widely used in high precision manufacturing industry.With the rapid development of industrial technology,the requirement for high precision transmission of RV reducer is becoming higher and higher,and its transmission accuracy depends on the processing accuracy of key components and the impact of meshing quality.Because of the special meshing motion relationship of cycloidal gear and the limitation of processing equipment,the guarantee of grinding quality and meshing characteristics of cycloidal gear under load has always been a difficult problem in the manufacture of cycloidal gear.At present,due to the bottleneck problems of low transmission accuracy and short service life of domestic reducers,they mainly rely on imports.The reason is that the research on load-bearing and meshing condition of RV cycloidal-pin gear transmission is relatively insufficient.In this paper,the bearing and meshing characteristics of RV cycloidal-pin gear planetary transmission under the influence of tooth profile errors are deeply studied by means of gear meshing contact analysis method,which provides some technical support for the way of cycloidal gear repair,the improvement of RV reducer motion accuracy and the replacement of imported RV reducer by domestic ones.1.Based on the forming principle of cycloid gear,the mathematical model of cycloid gear tooth profile is established,and the factors causing the tooth profile error in the process of machining and modification are analyzed.The tooth profile error value in the complete tooth profile of cycloid gear is obtained by measuring the gear measuring center,and the tooth profile with tooth profile error is reconstructed by NURBS fitting method.The parameter expression of reconstructed tooth profile is obtained.2.According to the meshing characteristics of reconstructed tooth profile and needle tooth profile,a method of calculating meshing clearance is proposed,which takes the minimum distance between cycloid gear profile and needle tooth profile as meshing clearance.The meshing clearance value of cycloid needle gear pairconsidering tooth profile error is calculated from the point of view of mathematics and engineering,and the influence rule of tooth profile error on meshing clearance value is obtained;and according to the calculation formula of transmission error,the meshing clearance value is calculated.The influence of tooth profile error on the transmission accuracy of cycloidal-pin gear is studied.3.According to the non-linear relationship between meshing contact force and elastic deformation of cycloidal-pin gear pair.In this paper,a reasonable deformation compatibility condition is proposed,and the meshing force analysis model of cycloid gear and pin gear is established.Under the static condition,the mathematical expressions of contact force and deformation of contact teeth considering the tooth profile error are obtained,and the mathematical model of the comprehensive curvature radius of cycloidal-pin gear considering the tooth profile error is established.The simultaneous parameters of the tooth profile error are calculated by using the principle of minimum energy.The influence rules of meshing teeth number,meshing range,contact force and transmission accuracy are discussed.4.Based on the reconstructed actual tooth surface points of cycloidal gear with tooth profile error,a three-dimensional analysis model of cycloidal gear is established,and the meshing method of the finite element model is studied.Through the finite element simulation analysis,the force magnitude and distribution of the cycloidal gear teeth under the action of tooth profile error and the distribution law of meshing marks at each contact point are obtained.The correctness of theoretical calculation is verified by comparison. |
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