Studies in Lubrication. I. The Theory of the Thick Film Lubrication of a Complete Journal Bearing of Finite Length

A successive approximation theory is developed for the hydrodynamics of journal bearing systems of finite length, the expansion parameter being the journal eccentricity. This is applied through the second approximation to full journal bearings of lengths exceeding the bearing perimeter. The existence of the lubricant source and associated end leakage is explicitly taken into account, it being assumed in the actual analysis that the source is set 90° in advance of the maximum film thickness. It is found that contrary to prevailing opinion, based on the infinitely long bearing theory, the friction coefficients and eccentricities for the systems are not uniquely determined by the ``Sommerfeld variable''—(r2/c2)(μN/P), where r=journal radius, c=radial clearance, μ=lubricant viscosity, N=journal speed in r.p.s., P=bearing load per unit projected bearing area. It depends also on the leakage flux or source strength. For the position of source assumed in the analysis the friction coefficients and eccentricities i...