A novel tribometer for the measurement of friction torque in microball bearings

A novel tribometer for the measurement of friction torque in silicon-based microball bearings is demonstrated. First, a new configuration of microball bearing is proposed based on the contact mechanics analysis. The bearing is fabricated using halo etch and intermediate layer bond processing methods and the friction torque test platform is then developed. It is found that the microscale rolling friction torque between microball and raceway exhibits a sublinear relationship with load, which is different from the case of macroscale rolling, and the Si3N4 ball bearings generate larger friction torque than 440C ball bearings under the same load. •A novel tribometer for friction torque measurement in micro bearing is presented.•A new configuration of microball bearing is proposed based on contact analysis.•The bearing is fabricated and friction torque test platform is developed.•A sublinear relationship between microscale friction torque and load is found.•Si3N4 ball bearings generate larger friction torque than 440C ball bearings.