Temperature-Dependent Rheology and Tribology of Lubrication Greases Investigated with New Flexible Platform for Tribological Measurements on A Rheometer

Abstract

A tribometer requires speed and normal force control as well as a torque measurement to acquire tribological data. An air bearing supported rotational rheometer allows the measurement of the same variables but in a broader range and with better accuracy. This and the intension to measure Stribeck curves as well as the static friction with one single instrument led to the idea to design an accessory turning a rheometer into a high resolution tribometer based on a ball on pyramid principle. Both rheological and tribological measurements on model grease samples in a temperature range from −40°C up to 60°C are presented. The influence of temperature could be monitored and a correlation between rheology and tribology was found. In addition a special ball bearing fixture is available, thus alloing the measurements of start-up and running torques as well as run-out times of ball bearings under different loads and temperatures.