Supersonic profiles with minimum drag

Abstract

This paper investigates the effect of gyroscopic moment on the induction of damage of a tapered roller bearing. High speed and high load are the typical characteristics of nowadays express trains which rely heavily on the tapered roller bearings. However, the phenomena of damage, especially for the side damage, of rollers and ring raceways in tapered roller bearings cannot be neglected with the occurrence of super speed trains in China. It first presents the geometry of a tapered roller bearing and then discusses the angular speed relationship between the rotations around the axis of shaft and self-axes of rollers. Gyroscopic moment is then established with geometry parameters of the bearing and physical parameters of the rollers. Then the effect of gyroscopic moment of rollers is discussed and the criterion that the pose of the tapered rollers should not be affected by the gyroscopic moment is obtained for the first time. This new theoretical result offers a design criterion for high speed tapered roller bearings. Analysis indicates that the gyroscopic moment could not bring any direct damage to the rollers and raceways but it does provide the boundary conditions to induce the side damage of rollers and raceways when the parameters of a bearing are not properly designed.