The Influences Of Vibration Impact And Variable Entrainment Velocity On The EHL Of Gear

This thesis gives a detailed research on the influences of the impact load , normal vibration and vriable entrainment velocity on the transient thermal elastohydrodynamic lubrication of involute spur gear using non-Newtonnian fluid, a series of complete numerical solutions have been obtained. At the same time, a isothermal EHL problem of circular arc gear is also studied. Mainly includes four parts: the influence of impact load on the transient thermal EHL of spur gear; the effect of the vrible entrainment velocity on the thermal mixed lubrication; the effect of normal vibration on the transient thermal EHL of gear tooth surface and the numerical analysis on the isothermal EHL of circular arc gear.Firstly, according to relationship of the drive and geometry in the spur gear, a transient thermal EHL model of an involute spur gear has been established. Based on multi-grid method, a complete solution has been obtained with considering the variation of entrainment velocity, equivalent curvature , impact load ,viscosity and density of lubrication and the temperature induced by the effect of one or two pairs of teeth engagement.Secondly, considering the variation of entrainment velocity with time, a complete solution of involute spur gear of time-varying thermal mixed lubrication has been obtained and the effects on the film pressure and thickness on the process of staring with different accelerations and decelarating with different decelerations have been analyzed.Thirdly, a normal vibration EHL model of an involute spur gear has been established considering the effect of time-varying and a numerical solution of transient thermal EHL is received, analyzing the influences of vibration frequency and oil ambient viscosity on the distributions of pressure ,film thickness and temperature.Lastly, based on circular arc gear engagement principle, a equivalent line contact EHL model of circular arc gear is established and a full isothermal numerical solution of elastohydrodynamic lubrication is also obtained with the muti-grid method . The effects of different parameters on the pressure and film thickness have been discussed.