Research On Vibration Characteristics Of Cageless Ball Bearing Of Variable Radius Raceway With Damage

When the magnetic field of the maglev bearing disappears,the cage bearing acts as a backup bearing to support the falling spindle.In order to make the rolling element of ball bearing without cage evenly distributed,some scholars have designed local variable radius raceway on the outer raceway.Due to the periodic motion of the rolling element,the variable radius raceway is damaged,which leads to the discrete failure of the rolling elements of the bearing without cage,and brings the vibration of the bearing in the operation process.Therefore,in this paper,the dynamic characteristics of the rolling body and the factors affecting the bearing vibration after the local raceway damage of ball bearing without cage are studied.The vibration model of damaged variable radius raceway bearing was established and studied by theoretical analysis,numerical simulation and experimental verificationFirstly,the motion of the rolling elements was analyzed,and the relationship between the effective radius of rotation and discrete distance of the roller was established considering the damage width and damage depth of variable radius raceway.On the basis of this,the velocity equation of adjacent rolling elements in the damaged variable radius raceway was established and the velocity difference of adjacent rolling elements was determined.The range of velocity difference and damage width of variable radius raceway in discrete failure of rolling elements is discussed.Further considering the contact mode between the rolling elements and the damaged raceway,based on the discrete failure of the rolling elements caused by the velocity analysis,the time-varying displacement and time-varying contact stiffness models and the collision models of the roller in the damaged raceway were established.All these provide basic analysis for subsequent bearing vibration.Secondly,the relationship between the displacement of the bearing inner ring and the contact deformation of the rolling body was analyzed based on the time-varying displacement of the rolling element in the damaged raceway.The contact force equation between the rolling body and the bearing inner ring in the damaged raceway was established.On this basis,the vibration equation of the ball bearing without cage in the damaged raceway was established.In the case of discrete failure of the rolling body,the damage parameter value of the variable radius raceway was determined by combining with the velocity formula of the adjacent rolling body of the damaged variable radius raceway.The vibration equation of damaged variable radius raceway was established and solved by Runge-Kutta method and MATLAB programming.The correctness of the theoretical analysis is verified by comparing the theoretical vibration characteristics with the law of numerical solution.Finally,taking the ball bearing without cage of damaged variable raceway as the simulation and test object,dynamic simulation research was carried out from three aspects by combining ADAMS software to determine the speed of rolling body,discrete spacing of rolling body and bearing vibration law;The vibration test of noncage damaged variable radius raceway ball bearing was designed.Electrical spark method was used to process local variable radius raceway in the outer ring of non-cage ball bearing.According to the different speed and different load,the vibration test of damaged variable radius raceway was carried out,and the theoretical model,simulation analysis and test were compared to verify the correctness of the vibration model theory.In this paper,through the analysis of the vibration characteristics caused by the damaged variable radius raceway ball bearing without cage,the influence of damage degree of variable radius raceway on the dispersion of rolling body was determined,and this research has important guiding significance for the design and application of cage free ball bearings with variable radius raceway.