Stack-up forces for normal and abnormal operating conditions in a railroad roller bearing assembly

Stack-up force distributions are obtained for normal and abnormal operating conditions in a class F (6 1/2 x 12) railroad tapered roller bearing-axle assembly for various friction coefficients, press-fits and cap screw preloads. Three conditions that affect the stack-up force distribution are considered: a steady-state normal-operating temperature distribution, a steady-state temperature distribution resulting from a stuck brake or a jammed outboard roller, and a transient temperature distribution due to multiple jammed outboard rollers. The steady-state normal or abnormal operating temperature have insignificant effects for nominal values of interference, friction and cap screw preload. However, the effect of the transient temperature due to multiple jammed outboard rollers on the stack-up system is detrimental due to localized high temperature gradients near the outboard cone area and a distortion of the original surface geometry of the cone.