A hybrid theoretical–experimental method for calculating friction torque of cam roller bearings

Cam roller bearings are widely used in various machinery due to their low friction loss and high reliability. With the pursuit of higher power density in modern machinery, cam roller bearings require more and more compact geometry to withstand increased external loads, leading to an elevated friction torque. However, the friction torque characteristic of the cam roller bearing has not been systematically studied yet, theoretically or experimentally. In this study, a hybrid theoretical–experimental method is proposed to calculate the friction torque of cam roller bearings. Firstly, the friction torque theoretical model of the cam roller bearing is developed based on the mixed elastohydrodynamic lubrication theory. Then a novel friction torque measurement system of the cam roller bearing is introduced. Based on experimental results, the uncertain parameters in the theoretical model are determined by nonlinear least-squared optimization. Finally, the proposed method is compared with the other commonly used models, demonstrating its superior capability in accurately calculating the friction torque of cam roller bearings. The main advantage of this method is that the sliding friction torque caused by asperity friction and hydrodynamic traction can be predicted more accurately. This method can facilitate a deeper understanding of the tribological mechanism of the cam roller bearing and be the foundation for investigating the further tribo-dynamic behavior of the cam and roller follower mechanism.