Analyses Of The Thermal Hydrodynamic Lubrication Of The Oil Film Between Elastic Rollers

Thermal elastohydrodynamic lubrication (thermal EHL or TEHL) of tapered rollershas been studied in this thesis. The content includes mainly three parts, i.e., thederivation of the gap formulas between a tapered roller and a plane, the isothermal andthermal EHL solutions of two cylinders and two tapered rollers in the same oropposite orientation.In the first part, the geometric characteristics of a tapered roller has been analysed,the gap formulas between the surface of a tapered roller and a plane has been derived.This formulas is valid not only to conical rollers, but also to cylinders.Following the first part and facing the engineering applications of conical bearingsas well as bevel and helical gears, the EHL problems in the contacts of two cylindersand two tapered rollers in the same or opposite orientation have been investigated, andisothermal solutions have been obtained in the second part of this thesis. Furthermore,the influences of some parameters or factors such as the conical angle, the generatrixmodifying function and its amplitude, the tilt angle between rollers and the modifyingradius of the roller ends upon the isothermal EHL behavior of two cylinders and twotapered rollers in the same or opposite orientation have been analysed. The results showthat, among all discussed modifying functions, the cosine modification is the mostbeneficial one to the lubrication of rollers, and changes of these parameters or factorscan always produce important effect on the film thickness in the middle part or at theends of rollers.The third part of this thesis was prepared on the foundation of the first and secondparts. In this part, firstly, the relation and difference among the solutions obtained under the thermal non-Newtonian, thermal Newtonian, isothermal non-Newtonian andisothermal Newtonian conditions have been analysed and discussed for the contactbetween two tapered rollers in the same orientation, and then the influences of theHertzian contact pressure and the slide-roll ratio on the lubrication performance of twotapered rollers in the same and opposite orientations have been investigated based onthe thermal non-Newtonian solution. It can be seen from the results that, in general, theexistence of the thermal effect is always hazardous, whereas the generatrix or endmodification is always beneficial to the EHL behavior in a contact in the discussedranges of input parameters.