Research On Thermal Elastohydrodynamic Lubrication Simulation Of Gear Contact Interface

Gear is one of the most important parts in the mechanical transmission system,and good lubrication is the necessary condition to ensure the normal transmission of the gear.In gear transmissions with severe working environment such as high speed and heavy load,if the design of gear is unreasonable,an effective oil film cannot be formed at the gear engagement,resulting in direct contact of the tooth surface,excessive friction coefficient and subsurface stress,causing problems such as large vibration noise and large heat loss,which will directly affect the performance and service life of the transmission system.Therefore,it is very important to carry out simulation research on thermal elastohydrodynamic lubrication of gear contact interface and accurately obtain elastohydrodynamic lubrication characteristic parameters such as oil film thickness and friction coefficient at the meshing of gear,so as to ensure good lubrication status of the meshing surface of gear.In view of the above problems,this paper started with the research on the finite element simulation calculation method of gear three-dimensional thermal elastohydrodynamic lubrication,and developed a digital simulation platform suitable for the calculation of gear elastohydrodynamic lubrication.Then,elastohydrodynamic lubrication characteristic parameters of gear contact interface are calculated,and the change rules of the characteristic parameters of gear elastohydrodynamic lubrication with the influence factors were revealed.The main research contents and conclusions are as follows:(1)Elastohydrodynamic simulation model verification.The elastohydrodynamic lubrication characteristic experiment was carried out to obtain the experimental measurements of oil film thickness and friction coefficient under different working conditions.The numerical theoretical model and simulation model of elastohydrodynamic lubrication were established respectively.By comparing the theoretical calculation results,simulation calculation results and experimental results,it was confirmed that the simulation method has high accuracy in the calculation of oil film thickness and friction coefficient.(2)Simulation research of gear thermal elastohydrodynamic lubrication.Taking the single meshing point of a single pair of high-speed heavy-duty helical gears as the research object,the numerical theoretical calculation,simulation calculation and subsurface stress calculation of the gear meshing were carried out respectively.The reliability of the simulation method of gear elastohydrodynamic lubrication was verified by comparing the theoretical and simulation results.(3)Development of digital simulation platform for gear elastohydrodynamic lubrication.Based on the gear thermal elastohydrodynamic simulation method,the flow design and GUI design of the gear elastohydrodynamic simulation platform were established,and an automated simulation platform was set up.The elastohydrodynamic lubrication parameters of the entire gear contact interface were calculated by the simulation platform,and the change rules of the elastohydrodynamic lubrication parameters in the gear contact interface were analyzed,which verified the feasibility of the gear elastohydrodynamic lubrication automation simulation platform.(4)Research on the influence of local elastohydrodynamic lubrication characteristics of gear meshing.By using the gear elastohydrodynamic lubrication simulation platform,the gear gnaking point was selected as the calculation base point to study the effects of different loads,different oil and gas ratios,and different environmental temperatures on the local elastohydrodynamic lubrication parameters of gear meshing,revealing the changing law of the oil film thickness,friction coefficient,the subsurface stress and stress depth with the influencing factors.And the reasons for the change were analyzed,which further indicated that the proposed method of gear elastohydrodynamic lubrication has engineering guidance significance.