Some uses for & properties of E.P. GREASES

IT is well known that many types of grease will function very efficiently when lubricated with an oil of suitable viscosity. In such cases, relative motion between engaging gear teeth is small and little heat is generated. When, however, considerable sliding action occurs, as between the teeth of hypoid gears, a straight oil is usually inadequate as a lubricant—particularly when the gears are new. Extreme pressure greases are sometimes employed for these purposes. These greases are specially compounded with a view to improving the film strength to such an extent that rupture does not occur at the highest working pressures encountered. Some valuable characteristics of extreme pressure greases are absence of channelling at low temperatures, no tendency to corrosion or abrasiveness, maintenance of homogeneity under all service conditions, ample capacity to carry the maximum loads and resistance to rupture under high pressures.