Study On Three-Dimensional Dynamic Contact Characteristics Of Gear-Shaft-Bearing System

With excellent characteristics such as high power transfer efficiency,compact structure and accurate transmission ratio,gear transmission systems are widely used in power transmission devices in the fields of automotive,marine and aerospace.With the progress of science and technology,various industries have put forward higher requirements for the service performance of gear transmission systems,for example,in the field of aviation and shipping,gear transmission systems must not only meet the basic strength requirements,but also have such characteristics as equal strength lightness,thus the support structure of the gear transmission system is generally more flexible,and this will greatly affect the load distribution and contact strength of the gear.In addition,in practice,due to the combined effect of internal/external excitation,vibration displacement is inevitable between the meshing tooth surfaces of the gear train,which not only seriously affects the life and work quality of the machinery and equipment,but can even induce serious safety accidents.Combined with the structural characteristics and working conditions of the gear transmission system,this paper establishes a three-dimensional contact analysis model of the tooth surface considering the system flexibility,and studies the influence law of the system parameters on the static three-dimensional contact characteristics of the tooth surface;establishes a three-dimensional contact-system dynamics coupling model of the tooth surface considering the system flexibility,and studies the influence law of the system parameters on the dynamic three-dimensional contact characteristics of the tooth surface.The research on the dynamic three-dimensional contact characteristics of gear-shaft-bearing system considering system flexibility is of great theoretical significance and engineering application value for predicting and regulating the actual three-dimensional contact state of tooth surface and system vibration and noise level of gear transmission system in real time and accurately.The research mainly focuses on the following aspects:Firstly,the research object is a single-stage gear-shaft-bearing system.Based on the idea of multi-point meshing of gears in the axial direction,a static three-dimensional contact analysis model of tooth surface considering the flexibility of the system(gear flexibility,shaft segment flexibility and bearing flexibility)and the solution method are established.The gear transmission system is discretized into a shaft segment unit,a gear mesh unit and a bearing unit using the finite element method,and the static model of each unit is established.Subsequently,the static model of the system is assembled according to the connection relationship between the units.The static contact performance parameters of the tooth surface considering the flexibility of the system are obtained by constructing an iterative format solution.The validity of the constructed model is verified by comparing the results with the3 D contact finite element calculations.Secondly,based on a three-dimensional tooth contact analysis model that considers system flexibility,the influence of system parameters such as shaft section structure,power transfer path,bearing stiffness and support method on tooth static three-dimensional contact performance parameters such as tooth contact stress and gear pair meshing misalignment is investigated.Then,to explore the coupling mechanism between the instantaneous three-dimensional contact characteristics of the tooth surface and the system vibration response considering the system flexibility,a coupled model of tooth surface three-dimensional contact-system dynamics considering the system flexibility is developed by coupling the analysis of tooth surface three-dimensional contact with the solution of system dynamics.The Newmark numerical integration method is coupled with a parametric proxy model of tooth contact performance,and an iterative solution algorithm for this model is constructed.Finally,based on a coupled tooth surface three-dimensional contact-system dynamics model considering system flexibility,the influence of system parameters such as input speed,input torque,shaft section structure,power transfer path,bearing stiffness and support method on tooth surface dynamic three-dimensional contact performance parameters such as dynamic meshing misalignment,tooth surface dynamic contact stress,gear dynamic transfer error and meshing dynamic load is investigated.