Considerations concerning friction in four ball scuffing test

Abstract

The paper presents some typical results regarding the evolution of friction torque during the four balls scuffing tests. The tests were conducted in 10 seconds running periods having 100 N loading steps, according to ISO 20623:2017. For testing, 12.7 mm bearing balls manufactured by SKF were used and as lubricant, U90Ca3 grease was used. A special device was conceived and built to evaluate the friction torque between balls using a force transducer mounted on the testing machine and a data acquisition module. A correlation between the loading, wear scar dimensions and friction torque was obtained. The results can be used to determine the precursory moment of scuffing initiation in four ball test using different lubricants. Some remarks concerning the working parameters inter-correlation during tests were also made.