Research On Dynamic Characteristics Of Gear Transmission System With Spalling Fault Considering The Lubrication Condition

Gear transmission has the advantages of stable transmission,strong carrying capacity,compact structure,high transmission efficiency and long service life.It has an irreplaceable role in the national machinery manufacturing industry and is widely used in aerospace,shipbuilding,automotive engineering,engineering machinery,processing machine tools,agricultural machinery,metallurgy,chemicals,electricity and other fields.However,the local teeth of the gears caused by manufacturing and installation errors are too large and long-term work in high temperature,high-speed heavy load,dust and other harsh environments may cause partial failure of the gears,resulting in insufficient lubrication of the gears.Gear failure and insufficient lubrication will seriously affect the dynamic characteristics of the system and aggravate the vibration and shock of the gear drive,thus further accelerating the failure of the gear transmission system.Therefore,the dynamic modeling method under the influence of lubrication and gear failure coupling is carried out to analyze the relationship between internal excitation and external dynamic response of the gear transmission system under the influence of lubrication and fault,and to solve the fault detection and diagnosis of the spur gear transmission system.In the gear transmission system with tooth surface spalling fault,the paper deals with the problems of contact characteristics,friction characteristics and system dynamic characteristics of the gears under lubrication conditions.The research on gear tooth stiffness,oil film stiffness and damping,friction force and dynamic coupling modeling of elastohydrodynamic lubrication(EHL)and spalling fault are carried out.The main research work of the thesis includes:(1)For the problem of the dynamic characteristics of the gear pairwith fault,the tooth stiffness calculation model is established according to the energy method,and the gear dynamics model of the tooth spalling fault is established by using the gear tooth stiffness excitation of the tooth spalling fault.The variation law of the tooth stiffness excitation and the dynamic responses of gear with spalling fault is obtained.(2)For the problem of EHL is formed for relative movement of the surfaces of the meshing pair in the gear transmission system with spalling fault,based on the theory of gear three-dimensional transient line contact EHL,the three-dimensional transient line contact of the tooth spalling fault is established.The EHL model obtains the variation of oil film pressure and thickness under the influence of spalling fault,load and sliding speed.(3)For the problem that the tooth surface peeling fault affects the gear contact characteristics under the lubrication condition,based on the EHL result of the tooth spalling fault,the oil film stiffness calculation model,the oil film damping and the friction force calculation model including the tooth spalling fault are established.The gear contact characteristics of the tooth spalling fault under lubrication conditions provide a calculation method.(4)For the dynamic characteristics of the system with tooth spalling fault under lubrication conditions,the contact characteristics and the dynamic behavior of the tooth spalling fault under the coupling lubrication condition,and the gear dynamics of the tooth spalling fault under the lubrication condition is established.The model provides a calculation method for studying the dynamic characteristics of the system under the influence of lubrication and tooth spalling fault coupling.(5)According to the dynamic modeling method of the tooth surface spalling fault under the lubrication condition,the fault simulation test bench was built to carry out the dynamic characteristic simulation experiment of the tooth surface spalling fault under the lubrication condition,and the vibration signal of the tooth surface spalling fault gear system under the influence of the lubrication condition was obtained.After that,the experimental gearbox parameters are input into the proposed model to solve the dynamic characteristics of the system,and compared with the measured signals to verify the correctness of the theoretical model.