Research On The Effects Of Modification Of Gear Elastohydrodynamic Lubrication

Gear drive is widely used in mechanical transmission, and in many cases alsoneed to use modified gear transmission. More research of standard gearelastohydrodynamic lubrication is studied by scholars, and the EHL research ofmodified gear is less. In this paper, positive drive modified gear is as the example foranalyzing the gear meshing theory of modified gear, and the ElastohydrodynamicLubrication (EHL) model of infinite line contact is established. The numerical analysisto modified gear of the EHL are analyzed by using the multi-grid method and themulti-integration method, and the numerical solutions of modified gearequal-modified, positive drive and negative drive of the EHL are obtained.Firstly, the EHL model of infinite line contact is established according to positivedrive modified gear, the film pressure and film thickness under the steady-stateisothermal conditions of positive drive modified gear and negative drive modifiedgear are compared with the pressure and film thickness of standard gear transmission.The influence of modification coefficient of the gear EHL numerical results under thepositive drive condition is analyzed in this paper. Under the condition of the steadystate, the EHL of modified gear is also studied by considering the thermal effect, thedifference of the thermal results between modified gear and standard geartransmission are analyzed, and the effects of modification coefficient on the thepressure and film thickness are discussed.Secondly, the transient isothermal elastohydrodynamic lubrication numericalresults are researched by considering the changes of the load, speed and radius ofcurvature of the gear meshing contact surface along the line of action. The distributiondiagram of the film pressure and film thickness under the equal-modified, positivedrive and negative drive conditions are obtained, and the correctness of the numericalresults is verified by Dowson-Higginson minimum film thickness empirical formula. Thirdly, the lubricating oil is assumed to be Ree-Eyring fluid, the transientthermal elastohydrodynamic lubrication completely numerical solution of involutemodified gear under the four conditions is obtained by considering the thermal effectand compared with the EHL result of standard spur gears.At last, the influence of surface roughness on the EHL of positive drive andnegative drive modified gear is studied by talking all the transient effect, thermaleffect and the surface roughness into consideration.