Patent ID: 7090404

Claim:
Rolling element bearing, comprising an inner ring, an outer ring and a series of rolling elements which are in contact with the raceways of said rings, an ultra-low viscosity fluid being present in said contacts having a kinematic viscosity v=(η o /ρ) of less than 2 mm 2 /s, wherein the surfaces of the rings and the rolling elements have asperities which can have solid-to-solid contact during operation of the bearing, characterised in that a factor D q is defined which is equal to Δ q √{square root over (η o )}α wherein Δ q =mean slope of the roughness, η o =dynamic viscosity at saturation conditions, α=pressure-viscosity coefficient, and in that the solid-to-solid contact of the asperities is reduced by selecting such design parameters and operating conditions of the bearing that D q is in the range from 8.0×10 −6 mrad s 1/2 to 1.36×10 −4 mrad s 1/2 .