Annular Contact Research Articles

An Annular Contact Friction and Boundary Lubrication Tester

A simple, inexpensive, easy to use, and very accurate annular contact friction and boundary lubrication tester is described. Data are presented to show excellent reproducibility and extremely low experimental scatter. The system allows the accurate simultaneous measurement of normal load, friction force, ambient fluid temperature, and mean surface contact temperature. Analyses are presented, which are applicable to other testers in addition to the present one, for determining the true mean surface contact temperature from a measured near surface temperature (determined with a thermocouple), and for calculating the viscous drag component of the measured friction (thereby allowing its separation). The tester is particularly well suited for simulating and studying the surface contact phenomena which arise in multiple disc brakes and clutches.