Thrust Cone Lubrication: Part 2: Elastohydrodynamic Analysis of Crowned Rims

Abstract

In a companion paper it was shown that an elastohydrodynamic lubrication (EHL) analysis of purely conical thrust rims leads to the prediction of severe thinning of the oil film at the edges of the thrust tracks. This paper describes the results of an EHL analysis of thrust rims having a crowned geometry. It is found that the presence of crowning greatly reduces the edge thinning effect, particularly at heavy loads, with the further advantage of making the thrust rims much more tolerant to misalignment due to elastic deformation of the gears. This is at the cost of a reduction in the film clearance in the central region of the contact. Crowned geometry is proposed as the basis of a design method for thrust cones, which is to be presented in detail in a further paper.