In rolling bearings, roller–cage collisions are one of the primary causes of cage damage. However, the underlying mechanisms remain unclear, particularly under high radial loads. In this work, a roller–cage collision experiment is conducted by measuring the cage beam force. Two distinct roller–cage collision modes are found: Under low radial loads, the rollers primarily drive the cage’s motion within the load zone, whereas under high radial loads, the cage beam initially encounters resistance before being driven by the roller. Bearing tribo-dynamic simulations reveal that the two distinct roller–cage collision modes are primarily caused by changes in contact deformation, which affects the relative surface velocities of the inner and outer raceways. The multimode characteristics of roller–cage collisions revealed in this work, as well as the mechanisms underlying them, are common in various types of radial bearings.

Friction force is a crucial factor causing power loss and fatigue spalling of rolling element bearings. A combined experimental and analytical method is proposed to quantitatively determine the elastohydrodynamic lubrication (EHL) friction force distribution between rollers and outer raceway in a cylindrical roller bearing (CRB). An experimental system with the instrumented bearing and housing was developed for measuring radial load distribution and friction torque of bearings. A simplified model of friction force expressed by dimensionless speed, load, and material parameters was given. An inequality constrained optimization problem was established and solved by using an experimental data-driven learning algorithm for determining the uncertain parameters in the model. The effect of speed, load, and lubricant property on friction force and friction coefficient was discussed.