Abstract: A universal equation to be applied for the closed - region is derived by the surface adsorption theory to correct Reynolds equation. The calculating result consists with one of Reynolds equation calculation in the region of thick film, and is in agreement with the reports and testing in the region of thin film in the present. The universal formulation describing provides theory basis for the engineering design and scientific analysis.

Key words: Closed - region, Thin film lubrication, Viscosity Adsorption layer