| Rolling bearing is widely used in the rotating support zone of mechanical systems,which plays the role in bearing load,reducing frictional resistance and ensuring turning accuracy.As an important element of the bearing,the cage not only makes uniform distribution of rolling elements in rotation,but also causes sliding friction between the rolling elements and the bearing,resulting in heating and life reducing.Therefore in this paper,an automatic discrete bearing without cage is proposed to make the rolling element decelerate and accelerate regularly and further produces an automatic discrete effect by designing a variable-speed curved surface on the outer ring of the bearing to change the radius of the rolling element.Studying on parameters design of variable-speed curved surface of the rolling bearing.Firstly,as variable-speed curved surface can keep the rolling bearing without cage automaticly discrete,geometric analysis method is used to analyze the characteristics of rolling element when passing through variable-speed curved surface,thereby determining the principle of automatic dispersion of rolling elements and establishing the parameter equation of variable-speed curved surface and the number of matching rolling elements.Then,motion characteristic of the rolling element in the bearing raceway is analyzed to determine the discrete effect of the variable-speed curved surface on the rolling element,and establish the equations of the revolution speed and discrete distance of the rolling element.Lastly,several schemes are presented to design structure and parameters of variable-speed curved surface based on 6206 bearing.Dynamic analysis of bearing with variable-speed curved surface.Since the structure and parameters of the variable-speed curved surface have a direct impact on the vibration of the bearing,first,the contact between the rolling element and the variable-speed surface is analyzed in order to define the influencing factors of the time-varying displacement on rolling element due to the introduction of the variablespeed curved surface and establish the time-varying displacement equation.Second,the equations of contact force between rolling element and conventional raceway,also rolling element and variable-speed curved surface are established based on analysis of the forces between the various parts of the bearing according to Hertz theory.Finally,combining the effects of contact deformation,time-varying displacement,contact force,and impact force on vibration during the process of contact between rolling element and variable-speed curved surface,a bearing vibration differential equation with variable-speed curved surface is established and solved based on the MATLAB-"Runge-Kutta" method to optimize structural parameters of the variable-speed curved surface.In order to verify the motion characteristics of the rolling element and the impact vibration caused by the variable-speed curved surface,dynamic virtual simulation is carried out to verify the rolling process of the rolling element passing over the variable-speed curved surface.Combined with the numerical analysis results,the discrete effect,discrete distance,revolution speed,vibration acceleration and other parameters of the rolling element are analyzed to verify the accuracy of the previous theoretical analysis and dynamic analysis results.Concurrently,it is further verified the rationality of designing structure and parameter of variable-speed curved surface by building a physical prototype to analyze discrete situation of the rolling element of bearing without cage.Automatic discrete bearing of rolling element without cage proposed in this paper extremely reduces friction resistance and has a certain significance for life improving of the bearing. |
