Analysis Of Dynamic Characteristics Of Sliding Of Rolling Bearing Considering Raceway Waviness And Cage Flexibility

As a basic mechanical component,rolling bearings are widely used in various fields such as the national economy and national defense.With the development of modern industrial technology,the requirements for dynamic performance of bearings have become increasingly high.The sliding dynamic characteristics of bearings are the main factor affecting their operating accuracy,reliability,and service life.Therefore,the sliding dynamic characteristics of bearings have become a current research focus,and many scholars have also carried out corresponding research.Currently,due to factors such as machining errors in mechanical equipment,raceway waviness has become one of the common defects in bearings,seriously affecting the dynamic effects of bearings.Moreover,in the current modeling process of most dynamic models,it is assumed that the cage is a rigid component,ignoring the effects of its own structure,materials,and lubricating oil.Therefore,there is a certain gap between the model analysis and the actual working conditions.In response to the shortcomings of the above research,this article mainly conducts in-depth research on the sliding dynamics characteristics from two aspects,and the main research contents are as follows:(1)Aiming at the dynamic modeling of bearings excited by raceway waviness,assuming that the waviness is a sine function,considering the effects of time-varying displacement and stiffness coupling excitation caused by raceway waviness,a sliding dynamic model of raceway waviness bearings is established through differential equations of motion of various components,and the accuracy of the model is verified by vibration acceleration signals and contact forces,At the same time,it is found that the dynamic effect of the bearing with waviness in the outer raceway is more stable than that with waviness in the inner raceway.(2)Based on the above established dynamic model of raceway waviness bearing slip,the effects of raceway waviness amplitude and order on bearing slip,mechanics,motion,and contact characteristics are analyzed.The results show that increasing the amplitude and order of waviness can reduce the slip phenomenon in the non bearing area,while the effects of raceway waviness in the bearing area,inner and outer raceways,on the slip characteristics are different;At the same time,the waviness also causes fluctuations in the contact force,and the number of fluctuations increases with the increase in the amplitude and order of the waviness.When the amplitude is large,the ratio of the contact force fluctuations caused by the waviness of the inner and outer raceways is consistent with the ratio of the characteristic frequencies of the inner and outer raceways.The increase in the amplitude and order of waviness reduces the contact stiffness of the raceway,and the change in the raceway stiffness caused by waviness is smaller than that of normal bearings.(3)Aiming at the dynamic modeling of rolling bearing with flexible cage,the cage is discretized into unit mass blocks,and the contact deformation and force between the roller and the cage mass block,as well as between the cage mass block,are analyzed.The effects of lubricating oil viscous resistance,rotor and bearing seat are further considered.A sliding model of flexible cage bearing is established,and the effectiveness of the model is verified through experiments and theory.(4)Based on the cage flexible bearing model,the dynamic characteristics of bearing slip under changes in load,rotational speed,acceleration,and composite factors were analyzed.The study showed that the cage connection stiffness had different effects on bearing slip under accelerated and stable conditions,and the impact of accelerated conditions was more obvious.Reducing rotational speed under high speed conditions and increasing load under light load conditions have more obvious effects on reducing bearing slip;The pocket gap only exacerbates the slipping of the cage and is accompanied by severe fluctuations;Considering the lubrication viscous resistance under acceleration conditions,bearing slip will experience a trend of "increasing-decreasing-slowly increasing".There is a significant dividing point between the impact of load and rotational speed on bearing slip.The impact of rotational speed on the right side of the dividing point is more significant,and the impact of load on the left side is more significant,while the impact of acceleration is always greater than the impact of load;Through the study of composite factors,a working condition matching formula for accelerating and stable conditions under slight bearing slip is obtained,which can effectively control the degree of bearing slip.This study provides a scientific explanation of the sliding characteristics and motion mechanism of rolling bearings,which can provide a certain theoretical basis and reference value for reducing the sliding characteristics of rolling bearings under the waviness of the raceway surface and for fault diagnosis using the dynamic characteristics of motion as characteristic signals.At the same time,the analysis of the sliding characteristics of rolling bearings with flexible cages can reduce the sliding of bearings Exploring the sliding mechanism and predicting the sliding of bearings have very important theoretical basis and practical value.