Design Method Research Of Sliding Bearing On Rod Based On Multi-body Dynamics

Sliding bearings are the important parts of industrial machinery.For modern high-speed and heavy-duty sliding bearings,they are no longer assumed to be rigid,and the elastic deformation during the movement can not be neglected.Considering the elastic deformation in the design methods is a new research direction for designing sliding bearings.Domestic and foreign scholars have made some progress for the studies of the elastic deformation of sliding bearings,but the studies were not complete and this problem should be investigated further.Based on these,the design methods of connecting rod bearing were analyzed,a MATLAB based automatic design program was established.The design methods and the working contents of the designer were analyzed in this thesis in order to reduce manufacturing cost and improve efficiency.First,the movement law and load characteristics of connecting rod bearing were investigated based on kinematics and dynamics analysis of the slider-crank mechanism which was one of the link mechanisms.And the angular velocity,angular acceleration and load formula of connecting rod bearing were summarized.Secondly,based on the applied loads on the bearing,the optimization model was established consisting of the objective functions,the design variables and the five constraint equations.The objective was to achieve the maximum capacity,the minimum heat and the minimum coefficient.The design variables included wide-diameter ratio,the relative gap and dynamic viscosity.The five constraint conditions involved the minimum film thickness,pressure,etc.Then the optimization design of the connecting rod bearing was achieved by applying MATLAB genetic algorithm toolbox.Thirdly,the difference method and Hertz formula were solved iteratively to obtain the elastic deformation of the sliding bearing based on the optimized structure parameters.The offset of surface roughness is compensated with the elastic deformation of the sliding bearing during the movements,which makes the elastic deformation counteract the roughness offset.The machining precision grade was reselected considering the new surface roughness after compensated.Finally,the automatic analysis rod bearing system was established based on MATLAB.The staff only input basic parameters,then the system outputs rod bearing angular velocity,angular acceleration,loads,optimization design results,film pressure,elastic deformation distribution and its average value,which achieves human-computer interaction,interface friendly,using easily and improves design efficiency.