Plain bearings must be evaluated for suitability in an application based on their pressure velocity value or PV value. Plain bearings are rated by their limiting PV, which is a combination of load over a given surface area and the velocity. In order for a plain bearing to be suitable for use without lubrication in an application, the following three parameters need to be met.
P = Maximum pressure or load in pounds per square inch (psi) or kilograms per square centimeter (kg/cm2)
Pressure is over the projected area of load where:
A = Projected Contact Area
L = Bearing Length
d = Shaft diameter
W = Maximum load