Viscosity and Its Relation to Lubricating Value.

SYNOPSIS The article describes what is meant by viscosity and the effect of that quality upon the “body” and lubricating value of an oil. The moving parts of a bearing are separated by a cushion of oil, the film adjacent to each surface sticking to that surface. The motion is thus between particles of the fluid, and the bearing obeys the laws of fluid friction. This gives the definitions that “fluid lubrication” is the sepaydon of solid surfaces by means of a fluid of suitable viscosity, and that “body” is this ability to be dragged between and so to lubricate surfaces. The resistances increase with the viscosity and the velocity, but decrease with increased clearance.