Vibration Characteristics Analysis Of Rolling Bearing Under Coupling Of Elastic Support And Oil Film Damping Condition

As a very important basic mechanical components,rolling bearings are widely used in a variety of systems which containing rotary motion.The motion performance of the rolling bearing is very important for the stability of the entire rotating system,especially as aero engines that require high-speed rotation of the spindle.In the paper,the vibration characteristics of the cylindrical roller bearings used in aeroengine are taked as research object,taking into account the elastic fluid lubrication and the squirrel-cage squeeze film damper condition.Based on the theory of elastohydrodynamic lubrication and the dynamic theory of rolling bearing,three different types of dynamic models of cylindrical roller bearing are established,successively considering the geometric deviations of the bearing manufacturing,the bearing lubrication condition,the coupling condition of squirrelcage squeeze film damper and the elastic fluid lubrication.Lagrangian approach is adopted to derive the dynamic differential equations of motion.The Runge-Kutta method is used to calculate the differential equations of motion.These provides theoretical guidance for the study of the vibration characteristics of cylindrical roller bearings.Based on the established dynamic model,taking the type of NU1004 cylindrical roller bearing as example,the vibration characteristics respectively considering manufacturing geometric deviations,the lubrication condition and the coupling condition,are studied in detail.The results shows that: the inertia effects could reduce the vibration responses of the roller caused by geometric waviness;with the increasing of the rotationa speed,the influence of the gravity was decreased,and the shaft orbit is closer to a circle;using,the static loading capacity of the squirrel-cage elastic support could offset the influence of the gravity,which made the mass center trace of the outer ring become a circle;when the rotating frequency is close to the natural frequency of the system,the vibration velocity and displacement of the rotor center-of-mass will increase dramatically;when the rotor is between the first and second order rotational speed,the displacement of the center-of-mass of the bearing ring would higher than the result under the first order rotational speed;with the increasing of the rotational speed,the rotating frequency of the rotor and the revolution frequency of the roller will both be increased.Eventually,the vibration of the NU1004 cylindrical rollerbearing was tested on the double pivot single disc rotor system and the improved BVT-5 measuring instrument.The comparison of the analytical results with the experimental data shows that the proposed model are correct.