Simulation Analysis Of Dynamic Characteristics Of Angular Contact Bearing With Plastic Cage

The plastic cage is a key component of angular contact ball bearings,which evenly distributes the rolling elements in the raceway and avoids collision and friction between the rolling elements.However,under harsh working conditions,the cage may deform due to thermal coupling,resulting in changes in the gap between the cage pocket and guide,and more obvious friction and collision between the rolling element and the cage,accelerating the failure of the cage.Therefore,clarifying the deformation of cages with different materials and working conditions,understanding the influence of working conditions and structural dimensions on the dynamic characteristics of cages,and the above issues are key to the design of cage structures.This article aims to design the cage structure,focusing on the dynamic characteristics of rigid flexible coupling plastic cages,low-cost cage materials,and cage design optimization.The main work content and conclusions are as follows:（1）A low-cost cage material was prepared by adding different proportions of CaCO₃to HDPE,and the effect of inorganic particle content on the properties of HDPE material was investigated.The mechanical and creep properties of the material were characterized by quasi-static uniaxial tension;The thermal properties of the material were analyzed using a thermogravimetric analyzer,differential scanning calorimeter,and static thermal mechanical analyzer.The results show that increasing the content of CaCO₃can improve the creep resistance of HDPE,improve the elastic modulus of HDPE,reduce the high temperature coefficient of thermal expansion,significantly reduce the melting enthalpy during the melting process,and reduce the power consumption during processing;The Eyring model can effectively describe the sensitivity of HDPE/CaCO₃mechanical properties to strain rate.When the tensile strain rate is greater than 0.003s^-1,the maximum tensile strength and elastic modulus gradually stabilize;The results of melting entropy and crystallization entropy of composite materials indicate that increasing the amount of CaCO₃filling can reduce the mobility of HDPE macromolecules.Based on the above material properties and performance analysis,provide data support for the design of low-cost HDPE/CaCO₃cages.（2）In response to the needs of dynamic analysis of bearing cages,a rigid body dynamic model of the bearing and a rigid flexible coupling dynamic model with a flexible cage were established.The simulation results of this method were compared with the results of Gupta’s classic examples to verify the effectiveness of the bearing cage model,laying the foundation for subsequent dynamic simulation of bearing cages and optimization design of cage structures.（3）Considering centrifugal force and thermal expansion effects,a theoretical model for plastic cage deformation was established,and the reasons for the differences between the theoretical calculation deformation and simulation deformation results were analyzed.A plastic cage centrifugal expansion deformation experiment was designed,and the experimental results were compared with the simulation results,and the reasons for the differences between the two were analyzed.（4）The dynamic model of rigid flexible coupling plastic cage bearings established by Adams explains the influence of material properties,elastic modulus,and temperature factors on the vibration mode of the cage.The lower the elastic modulus,the higher the operating temperature,and the higher the modal frequency,the less likely the cage to resonate.The influence of changes in guide clearance and pocket clearance on the dynamic characteristics of the cage has been clarified,that is,as the guide clearance increases,the velocity deviation ratio of the cage decreases,and the motion stability of the cage increases.However,an increase in guide clearance will lead to an increase in the amplitude of centroid displacement,and the guiding effect of the outer ring on the cage will gradually degenerate into rolling element guidance,weakening the constraint effect of the guide on the cage;When the guiding gap decreases,the cage will expand radially due to centrifugal force,causing friction and collision between the guiding surface and the cage;As the gap between the pockets increases,both the equivalent stress and contact collision force at the pocket of the cage will increase,and the deviation ratio of the cage speed will increase,reducing the stability of the cage movement.At the same time,increasing the pocket gap will also lead to a decrease in the modal frequency of the cage,which is not conducive to avoiding resonance;Reducing the gap between the pockets can improve the stress state at the pockets,but at high speeds,the cage will expand radially due to centrifugal force,leading to shrinkage of the pockets and affecting the movement of the rolling element.Studied the dynamic characteristics of the cage at different speeds and speeds.The higher the rotational speed,the ratio of the maximum dynamic stress to the average dynamic stress of the cage shows a trend of first decreasing and then increasing.The smaller the deviation ratio of the center of mass velocity,the more stable the movement of the cage;When the bearing acceleration increases,the dynamic stress of the cage increases,and the change in maximum equivalent stress is more significant than the average equivalent stress.The random fluctuation of the cage increases significantly,and the dangerous points are located at the pocket crossbeam,side beam,and guide surface of the cage.The influence of plastic cage imbalance on the stability of bearing cage motion was analyzed.The results showed that when the high speed and high imbalance were large,the center of mass vortex trajectory was more regular,and the stability of cage motion was improved.However,at this time,the amplitude of cage center of mass displacement increased.（5）Using the pocket clearance and guide clearance as the design variables of the cage,and the deviation ratio of the cage’s center of mass velocity and the effect force at the danger point as the design evaluation objectives,a regression equation between the design variables and the evaluation objectives was established through simulation experiments and response surface methodology,verifying the reliability of the regression equation.A mathematical model for optimizing the design of the cage structure was established based on design requirements.A fast non dominated sorting genetic algorithm（NSGA-II）with elite strategy was selected to solve the mathematical equations,and the ideal design variables in the Pareto solution set were determined.The motion stability and stress state of the model before and after optimization were compared.The results showed that the displacement response of the center of mass was slightly reduced and the equivalent stress was reduced by 3%after optimization,The dynamic characteristics of the cage have been improved.