Starting and Steady-State Friction Torque of Grease-Lubricated Rolling Element Bearings at Low Temperatures—Part I: A Parameter Study

An experimental investigation of the friction torque in a roller element bearing was made. The aim was to sort out parameters important to bearing torque, and to see whether they interact. Friction torque in grease-lubricated bearings were compared to bearings lubricated with the corresponding base oil at −20° and + 20°C. Also, base oil viscosity, NLGI number, load and acceleration at start-up xuere varied. No statistically significant difference was found between a grease and its corresponding base oil, independent of temperature, load or starting procedure and irrespective of which base oil that is considered. Most important to start-up torque was base oil viscosity. The effect was more pronounced at −20° C at all combinations of the parameters. Running torque after a −20°C start was not as dependent on type of base oil and base oil viscosity.