Selection And Analysis Of Collision Characteristics Of Auxiliary Bearing In Vertical Magnetic Suspension Bearing System

The auxiliary bearing is an important component used to support the high-speed falling suspension rotor in the active magnetic suspension bearing system.It is of great engineering application value to study the collision characteristics of auxiliary bearings when the rotor falls.This article takes vertical magnetic levitation bearing system as the object.Combined with the working conditions of the vertical magnetic levitation bearing system,full complement angular contact hybrid ceramic ball bearings are used as auxiliary bearing.The static characteristics of the auxiliary bearing,as well as the impact force and thermal characteristics of the vertical rotor falling onto the auxiliary bearings are studied.Using the finite element method,the finite element analysis model of the auxiliary bearing under the vertical rotor working condition was established,and the influence of the constraints and bearing capacity on the contact stress and elastic deformation of the auxiliary bearing was studied.The results show that full complement ceramic ball angular contact bearing have stronger bearing capacity than ordinary angular contact ball bearing.It is more appropriate to select full complement ceramic ball angular contact bearing.Increasing the radial load can significantly enhance the contact stress and deformation of the auxiliary bearing.However,increasing the axial load has no obvious effect on the contact stress and deformation of the auxiliary bearing.With full-filled hybrid ceramic angular contact ball bearing as auxiliary bearing,the rotor-auxiliary bearing system was subjected to a force analysis,and a dynamic model of the rotor-auxiliary bearing was established.Use the multi-body dynamics software to simulate the impact force of the auxiliary bearing when the rotor falls onto the auxiliary bearings.The influence of the protection gap,friction coefficient,rotor quality,and rotor drop speed on the rotor’s non-eccentric rotor’s impact on the first axial impact force of the auxiliary bearing during the fall of the vertical balance rotor to the auxiliary bearing was analyzed.The results show that,the initial axial impact force on the auxiliary bearing is the maximum value of the axial impact force;The initial axial impact force of the auxiliary bearing decreases with the increase of the dynamic friction coefficient;increases with the increase of the axial protection gap and the mass of the rotor;it remains unchanged as the drop speed increases.The axial collision force of the auxiliary bearing can be reduced by approp riately increasing the friction coefficient,reducing the axial protective gap and rotor mass,and reducing the impact of the axial impact on the auxiliary bearing.The influence of the falling speed and dynamic balance accuracy level on the collision force under the eccentric state of the rotor is analyzed.The results show that when the rotor is eccentric,as the rotor drop speed increases,the axial impact force on the auxiliary bearing remains unchanged,and the radial impact force increases accordingly.As the higher the level of dynamic balance accuracy,the greater the radial collision force suffered by the auxiliary bearing,and the axial collision force slightly increases.The dynamic balance accuracy level has a more significant impact on the radial impact force of the auxiliary bearing.According to the internal load of the auxiliary bearing in the magnetic bearing system,the heat generation of the bearing was analyzed,and the relationship between heat generation and heat transfer between the auxiliary bearing parts was studied.According to the working conditions,the corresponding thermal boundary conditions are set,the finite element method and the thermal network method are used to analyze the thermal characteristics of the auxiliary bearing,and the temperature distribution of the auxiliary bearing is obtained.The results show that the maximum temperature of the auxiliary bearing is at the end face of the inner ring facing away from the mouth,the outer ring temperature is less than the ball temperature,the ball temperature is less than the inner ring temperature,and the inner and outer ring temperature distributio n is asymmetric.