Research On Nonlinear Contact Mechanism Of Cycloidal Pinwheel Transmission Of RV Reducer

RV reducer is the key part for Industrial Strong Foundation Project of China.As the key transmission part of RV reducers,it is of great theoretical significance and engineering values to make the mechanism cycloidal pinwheel clear.The cycloidal pinwheel transmission mechanism is taken as research object.The load contact analysis model and thermal lubrication analysis model of the system are constructed.The time-varying nonlinear contact characteristics of cycloidal pinwheel transmission mechanism in the lubrication state is explored based on numerical analysis.The influence of different design parameters and working parameters on the contact characteristics of the system is revealed,the details are as follows:(1)A three-dimensional load-bearing contact analysis model of cycloidal pinwheel transmission mechanism is established,which comprehensively considers tooth profile modification and machining errors.Based on the principle of gear meshing and Nonlinear Hertzian Contact Analysis Theory,the time-varying contact characteristics of the gear teeth and the dynamic joint surfaces of the inner and outer rings of the crank bearing are studied.The influence degree of cycloid gear tooth profile modification,pin tooth error and crankshaft eccentricity error on system transmission error is found out.The change law of the nonlinear contact characteristics such as the number of meshing gear teeth,the magnitude and distribution of the force on the gear teeth,and the force on the needle rollers of the crank bearing are revealed.(2)A three-dimensional topography model of gear teeth,which comprehensively reflects the characteristics of macro profile and micro topography,is constructed.Based on differential geometry method and fractal theory,the vector equation of any rough surface profile is deduced by Superposition Method.To solve the convergence problem of the appearance model,the Gaussian Filtering Method is used to denoise the model,which solved the non-derivative problem of the fractal function and improved the computational efficiency of the model in contact analysis and lubrication analysis.The validity of the model is verified by experiments..(3)The dry contact analysis model of gear teeth considering the elastic-plastic deformation mechanism of asperities is constructed.The method for solving the contact gap of gear teeth based on Discrete Convolution Fast Fourier Transform is studied.The influence of load on the dry contact characteristics of cycloid gear teeth and pin teeth,a rough surface contact proportional coefficient formula including the macro and micro characteristic parameters of the tooth surface is proposed.The accuracy of the formula is verified by numerical simulation experiments.A fast calculation of the contact degree between rough surfaces is achieved.(4)The time-varying lubrication analysis model of the dynamic joint surface of the cycloidal pinwheel transmission mechanism is established.The transient lubrication characteristics of the contact area are solved by the mesh progressive refinement method and the indirect iterative method.The effectiveness of the model is verified by the ball-disk film thickness experiment.It is verified that the three-dimensional transient distribution of film thickness and pressure at the meshing of cycloid gear teeth,pin teeth and crank bearings is clarified.The influence of gear tooth modification,load,entrainment speed and other factors on the lubrication characteristics of the dynamic interface of the system is revealed.(5)Considering the thermal effect,the lubrication analysis model of the cycloidal pinwheel transmission mechanism is constructed,and the calculation equation of the transient heat distribution of the three-dimensional rough contact surface is deduced and solved.The time-varying deformation of the lubricating area,the thickness of the lubricating film,the contact pressure and the temperature rise are studied.The accuracy of the model is verified by the temperature experiment of the inner raceway of the RV reducer bearing.The dynamic thermal lubrication characteristics of the inner and outer rings of the bearing,the meshing gear tooth pair and the whole process of single pin tooth meshing are clarified.The evolution law of thermal lubrication characteristics of cycloidal pinwheel transmission mechanisms is clarified.