| Helical gear system is widely used in machinery,power,aerospace and other fields.In this dissertation,the dynamic behavior of the system was expounded by taking the helical gear system support by angular contact ball bearing as research object.Firstly,the base theory of the helical gear system support by angular contact ball bearing was studied: relation between reacting force and center displacement of a angular contact ball bearing,the nonlinear mesh force of helical gear system.Then the nonlinear behavior of the rotor system support by angular contact ball bearings was obtained.Finally,based on the above research,the behavior of the helical gear system support by angular contact ball bearings was studied by using the Runge-kutta numerical integral method.The main works and conclusions are as follows:1.2-DOF pseudo-rigid-body model is applied,according to the mechanical and deformation characteristics of forced component in bearings.Contact force between rolling bearing rings and balls is obtained by force method in the given axial and radial displacement of bearing center.By this way the axial force,radial force and reacting torque of the bearing is also figured out.The influence of balls centrifugal force,gyroscopic moment,location of roller on force and deformation is discussed at the same time.2.A dynamic model of 5-DOF angular contact ball bearing-rotor system is established in order to analyze the nonlinear behavior of the rotor system.The dynamic differential equations are derived with the relation between the reaction of the angular contact ball bearing and displacement of the rotor journal centre.The nonlinear behavior of the rotor system applied on axial force is mainly discussed.The result shows that: the response of the system develops from periodic motion,period doubling motion,quasi periodic motion to chaotic motion with the increasement of the axial force.The bearing stiffness is changed and the dynamic behavior of the two journal centres of the rotor are extremely different due to the action of axial force.3.A dynamic model of angular contact ball bearing-rotor-gear system is established in order to analyze the nonlinear behavior of the helical gear system.And the dynamic differential equations of the helical gear system are derived.The nonlinear behavior of the helical gear system applied on axial force is mainly discussed,which affected by the varied stiffness of the angular contact ball bearing and the nonlinear mesh force of the helical gear.The result shows that: the amplitude frequency characteristics,amplitude and reactions of the bearings of the different sides of the angular contact ball bearing center are significantly different in the helical gear system.The amplitude of the angular contact ball bearing center,which the axial mesh force point in,is smaller,and the axial force of the angular contact ball bearing center is larger.The radial amplitude of the right side is only 47.2% of the left side.The transmission of the helical gear system is smooth.The mesh force of the helical gear system display periodic variation.The range of the gear speed is no more than 0.1%,when the gear spins 3000 times a minute. |
