Dynamic Analysis Of Shaft-Rolling Bearing System Under Moving Load

The shaft-rolling bearing system,widely used in the mechanical equipment,is the most basic structural unit in the mechanical equipment.High-speed,high-power and high-precision are one of the important directions for the development of modern machines.Therefore,the dynamic characteristics of the rolling bearing-rotor system have always been studied by scholars at home and abroad for years.The dynamical probem of shaft-roller bearing system under moving loads is studied in this paper,so that the dynamic performance of the shaft-roller bearing system under moving loads can be predicted.It is significant to improve the machining accuracy and workpiece quality in manufacture.First of all,the relationship between rolling bearing reaction force and deformation is studied in this paper,a two-degree-of-freedom quasi-rigid body model is set up to obtain the formula between the reacting force of the angular contact ball bearing and the displacement of journal center.Necessary conditions are provided for solving the dynamics problem of the shaft-bearing system.Secondly,a ball bearing-rotor system,which is composed of a shaft and two ball bearings,is selected to research its dynamical characteristics.The dynamic simulation model of the system is established in ADAMS,a commercial dynamical simulating software.The amplitude frequency response and dynamic response of the system under moving load are studied.The influence of the load moving speed and the rotational speed of the shaft on the dynamic performance of the system is discussed.Thirdly,The ADAMS dynamics simulation model of a shaft-angular contact ball bearing system under the action of moving loads is established and solved.The amplitude frequency characteristic and resonant response of the shaft-angular contact ball rotor system under the action of moving load are studied.Several dynamic influencing factors such as the action of pretightening force,speed of moving load,rotating speed are also emphatically discussed.The calculation results show that:1)The resonance phenomenon of the small damping vibration system appears under the action of moving excitating force with resonance frequency;2)The response of shaft rolling bearing system under the moving force is strong nonlinear,particularly in the shaft-angular contact balling bearing system for there are some nonlinear charactistics in the response curve,such as zigzag,peak trailing and approximate straight line,etc;3)the dynamic relationship between the 2 bearings such as the amplitude of the journal center,thereacting forces is as one falls,another rises.Finally,The main work and innovation are summarized in this paper,and some opinions are putted forward on the future research.