Precision Analysis Of RV Reducer And Design Of A Novel Reducer

Industrial robots have urgent demand of high precision and efficiency reducer at present.By analyzing the structure and transmission principle of RV(Rotate Vector)reducer,investigation on its geometric characteristics,elastic statics,dynamic precision and development of a novel reducer are implemented.The thesis provides a theoretical basis for high precision reducer structural design,precision analysis and performance optimization.The main work and outcomes are as follows:The structure and transmission principle of RV reducer are analyzed.For the low speed cycloid-pin transmission mechanism,the tooth profile of cycloidal gear is derived by inversion method,and displacement matrix is established.Explicit expression of curvature radius and meshing angle are constructed with the rotation of crankshaft.The results show that radius of curvature between the cycloidal addendum and dedendum is infinite.Besides,the amplitude of meshing angle will decrease monotonous with the decrease of eccentricity.The static model of RV reducer is established with consideration of the geometric errors.Based on the Hertz contact theory,the position of meshing point and its contact stiffness between cycloidal gears and pins is analyzed.This model can reveal the actual meshing number,meshing forces of each gear tooth,bearing forces and load torques of rotating component are obtained.It is found that the number of meshing teeth is determined by the geometric error,load and crankshaft rotation angle.With cycloidal installation error increasing,the difference between the load torque of cycloidal gears increases.The load torques of output disk and rigid disk fluctuate as the crankshaft rotation.Considering meshing stiffness,bearing stiffness,rated speed and load torque,the multi-body dynamic model of RV reducer is established by using the lumped parameter method under UG environment.The mechanical characteristics and dynamic transmission precision are analyzed though the ADAMS solver.The results show that force of all the bearings varies periodically versus the rotation of the output disk and crankshaft.Compared with the supporting bearing,the turning arm bearing’s force amplitude fluctuates much greatly.With the increase of the modification parameters and load,the total hysteresis increases gradually.The influence of rotary transmission error on above factors is not obvious.Through the analysis of the structure and principle transmission of RV reducer,the topological structure is analyzed in detail.Combined with single-stage movable teeth drive of high stiffness and large speed ratio,a novel configuration of a two-stage closed transmission is discussed.The virtual prototype is built in UG environment,and the feasibility of the transmission form is verified by the kinematic characteristic simulation,which provides a new idea for the innovative design of high precision reducer.