Patent ID: 7806598

Claim:
A method for enabling bearing assemblies to sustain operation under oil-out conditions, the bearing assemblies comprising inner and outer races and roller elements positioned between the inner and outer races, the roller elements having opposed end surfaces and a side surface; one or both of said end surfaces defining a sliding surface and said side surface defining a rolling surface; the method comprising: determining a thickness of a tribological metal carbide coating sufficient to enable the bearing assembly to operate for at least a predetermined period of time in the absence of oil, the thickness of the coating being determined according to the equation: d = K ′ ⁢ Pv n ⁢ ( t - t 0 ) where d=coating thickness P is the ratio of force applied to the roller elements/contact area; v is the sliding velocity; n=the number of roller elements; (t−t 0 )=the desired operating time after oil-out condition starts; and K′ is the Archard constant; and the ratio d/K′ greater than 10 11 Pa-m; and applying the tribological coating to one or both end surfaces of the roller elements.