Mixed Lubrication Analysis Of The Involute Gear Based On Deterministic Model

Because contact occurs in a very small area, there is extremely heavy pressure in high pair contact such as gear, rolling bearing. The elastic deformation of surfaces and the change of lubricant viscosity must be taken into account when this kind lubrication mechanism is studied, and the lubrication theory which includes these two effects is called Elastohydrodynamic Lubrication(EHL or EHD) . Most of the gear transmission work under the mixed-EHL with asperity contact. In this paper, many operting conditons, which from smooth contact to rough contact, full-film EHL to partial-film EHL and line contact to point contact, are discussed, at last, mixed-EHL model of involute gear is established. The primary coverage includes:Mathematical models of line and point contact are established respectively, and then program is written to solve them, the results show the restriction of the film in the outlet region, the sharp pressure spike at outlet and horse-shoe in the contour plot of point contact.The isothermal transient full-film EHL problem is solved in point contact with roughness by 3 direct iterative solutions, and compared, then the pressure and film distribution is got.Geometric and motion parameters of involute spur gear are simplified, meanwhile deterministic model of mixed lubrication in line contact is first built in our country. The entire course of gear mesh is considered as a cycle and divided into many time nods, every time nod is solved by numerical solution step by step Then the pressure and film distribution along mesh line is given. Many contact situations such as smooth surfaces contact, contact with roughness and contact with asperity are analysed, the maximum pressure and minimum film thickness are compared , the places which film may broke are pointed out. The effects of power and speed change are discussed too. At last, deterministic model of mixed lubrication for the profile modifying gear is established, the steady state solution of several mesh change points are calculated, the law of the maximum pressure and minimum film along the mesh line are obtained.