Research On Nonlinear Dynamic Of Aviat Ion Bearing

With the rapid development of modern industrialization,aerospace intelligent manufacturing equipment needs higher stability and reliability.Due to the difficulty of spacecraft maintenance in orbit,it is necessary to calculate and simulate various accident conditions that will occur during the initial design phase.The space bearing is the most important component of the rotary joint of the spacecraft.Its reliability is the basic guarantee for the normal operation of the organization and the realization of the booking function.In order to reveal the nonlinear dynamic behavior of the precision bearing,the dyna mic model is established for the number of steel ball,the axial direction pre-tightening and the dynamic loads.The relative displacement between the inner and outer ring of the steel ball is derived.The system nonlinear dynamic differential equations and coordinate transf ormation of differential equations are worked,and the non-dimensional treatment is carrie d out.The dimensionless differential equations is solved by the numerical analysis softwar e.The phase diagram and Poincare diagram are obtained through changing axial direction pre-tightening size,analysis axial direction pre-tightening’s influence on the system’s nonl inear dynamic characteristics.The results show that the axial direction pre-tightening has a n influence on the motion state of the system.With the reducing of the axial direction pre-t ightening,the system enters the periodic movement through the chaotic motion,and then e nters the chaotic motion through the quasi-periodic.Under the condition of the system’s st ability,reducing the axial direction pre-tightening can improving bearings’ life;With the increase of contact angle,the system enters a multi period motion through the period doubling bifurcation,and the system enters the chaotic motion state through the unstable attractor.By uniting the three-dimensional drawing software and the dynamics simulation software,the trajectory of the centroid of the cage is simulated under the different preload and velocity,respectively.As the bearing velocity increases,the trajectory of the centroidof the cage tends to a regular circle,and the scope is getting larger and larger and no longer grows until it reaches a certain number.As the velocity of the inner ring increases,that of the centroid of the cage also increases linearly.Proper preload force will also make the cage run more smoothly.An experimental platform for measuring the stiffness of shaft systems was designed and built to simulate the static and dynamic stiffness characteristics of joints of special equipment.It can be found through experiments that the static and dynamic stiffness of the shaft system are all increased gradually with the increase of the initial preload,and the growth rate decreases.Under the condition of same preload,the larger the velocity,the smaller the dynamic stiffness.