This paper sets forth the differences between standard sealing systems and elastohydrodynamic sealing systems and reviews a report on the latter prepared by a subcommittee of the SAE Transmission and Drivetrain Committee.
An elastohydrodynamic sealing system requires a supplemental sealing device either on the seal itself or on the shaft. The paper describes unirotational and birotational seals for both types of design. It also discusses methods used in evaluating elastohydrodynamic seals, points out the limitations of each, and concludes by narrowing the field of suggested methods to three (visual examination of the seal on a plastic shaft, roll-coined spiral-grooved mandrel testing, and oil drop testing).
