Rigid Flexible Coupling Multi-body Dynamics Analysis Of Thin Walled Four Point Contact Ball Bearing

Industrial robots are widely used in automobile manufacturing,machining,aerospace and other fields.The dynamic characteristics of wrist joints have an important influence on the dynamic performance index of the industrial robot,such as the stability,positioning accuracy and reliability.Thin wall four point contact ball bearing as the key supporting special bearing of industrial robot,the current research on this kind of bearing only stays in the static stage,unable to meet the research needs of industrial robot bearing.The dynamic characteristics of the large and medium size four point contact ball bearing with special crown type structure under the condition of variable speed and acceleration is the difficulty of the research on the dynamics of the industrial robot.By using the method of multi-body dynamics and finite element method,special bearing retainer and crown structure in large size and thin wall ring deformation,complex dynamic contact relationship between the various components,the establishment of industrial robot with rigid flexible coupling of thin walled four point contact ball bearing and the dynamic model of the wrist joint.Calculation of dynamic performance analysis of thin-walled four point contact ball bearing and the wrist and cage stability and the influence of elastic deformation and other important issues,to provide theoretical support and basis for the domestic independent research and development of high performance of bearings.The main research work of this paper is as follows:(1)Hertz contact theory based on stress and contact deformation theory calculation of thin-walled four point contact ball bearing contact point contact problem and the basic equations of load distribution,influence of meshing and contact parameters on the results of using the finite element method to establish the static model of multi body contact single rolling body and the bearing,analysis at different radial loads and four point contact deformation and load distribution,and the feasibility of Hertz theoretical calculation results verified.(2)Based on the multi-body dynamics,a thin four point contact ball bearing analysis model of multi rigid body dynamics using ADAMS software,calculate the specific thin four point contact ball bearing movement form,the contact law and other dynamic characteristics,dynamic performance of thin walled four point contact ball bearings with different speeds and pretightening force under the conditions of the analysis,obtained four point contact characteristics and change law.(3)Considering the elastic deformation of the middle and large size thin wall ring and the special crown type cage,the flexible body model of the inner and outer rings of Wacom is established based on the ADAMS/Flex module and the finite element modal analysis.Considering the four point dynamic contact relationship between steel ball and flexible ring,a rigid flexible coupling multi-body contact dynamic model of thin walled four point contact ball bearing is established.Comparative analysis of the dynamic contact characteristics of ball bearing multi rigid body and rigid flexible coupling conditions,can not be ignored and the size of the vibration displacement show that the dynamic contact force of large size thin-walled ball bearing elastic deformation and dynamic effect of the four point contact.(4)Established by the base of wrist joint,analysis model of multi-body contact dynamics of two sets of thin walled four point contact ball bearings and two hollow shaft,in static conditions to calculate deformation results of the hollow shaft,ring and base;flexible on the pedestal and the hollow shaft,dynamic analysis is carried out on the whole the flexible wrist of rigid flexible coupling multi-body contact dynamics simulation system,different load ratio and reversing speed variable pitch motion and acceleration,dynamic performance of thin walled four point contact ball bearings and its influence on wrist key system.