Modeling And Dynamic Characteristics Of Planetary Gear Transmission In Non-inertial System Of Flight Environment

Planetary gear transmission system has the advantages of high transmission ratio,high reliability and compact structure,so it is widely used in aerospace,wind power generation,automobile,ship and other fields.Traditional research on the dynamics of planetary gear transmission system,whether elastic support or rigid support,assumes that the system is supported on a static basis,which is inconsistent with the operating environment of planetary gear transmission system in aircraft.The planetary gear transmission system in flight environment is a space movement of random body,which is affected not only by gravity but also by additional loads such as inertia force and Coriolis inertia force.These additional loads will affect the dynamic performance of planetary gear transmission system.It is of great significance to study the dynamics of planetary gear transmission system in non-inertial system of flight environment for guiding the design of aerodynamic power transmission system in non-inertial system of flight environment.In this paper,the planetary gear train in the main reducer of helicopter is taken as the research object.Considering the comprehensive influence of the external non-inertial system and the internal non-inertial system of the planetary gear train in maneuvering flight,the expressions of the motion parameters of the central component,planetary gear and casing under the condition of arbitrary maneuvering flight are derived.Considering the flexibility of shafting components,a coupling dynamic model of downlink star gear transmission system in non-inertial system in flight environment is established based on nodal finite element method,and a variety of internal non-linear excitations are considered.Based on two kinds of maneuvering flight conditions,the dynamic characteristics of downward star gear transmission system in non-inertial frame and the dynamic behaviors of components under different non-inertial conditions are studied.1)The kinematics model of the central component,planetary wheel and casing of planetary gear transmission system is established when the body moves in arbitrary space.The nodal finite element method is used to establish the dynamic model of gear-rotor system,and the Super-Element Method is used to establish the dynamic model of casing.On this basis,a coupling dynamic model of planetary gear transmission system considering non-inertial system in flight environment is established.2)Based on the system dynamics model in the non-inertial system of flight environment,the time/frequency characteristics of the downlink star gear transmission system in the non-inertial system are studied.The influence of body hovering motion parameters on dynamic behavior of various components under different non-inertial conditions was studied.3)Based on the system dynamics model in non-inertial frame of flight environment,the dynamic response of the flight process is obtained.From the point of view of time history,the relationship between the different motion parameters and the dynamic behavior of the system is studied.By changing the motion parameters of the body during subduction and pull-up,the dynamic behavior of the system under different non-inertia conditions and different time periods was studied.4)By comparing the dynamic characteristics of planetary gear transmission system under two maneuvering flight conditions,some similarities are found,including the variation of vibration displacement and vibration balance position of each component,bearing force and vibration acceleration.The special laws of dynamic behavior of planetary gear transmission system under two maneuvering flight conditions are also summarized.One is the influence of gravity radial component force and additional inertia force,the other is the influence of motion parameters under non-inertia conditions.