A resilient, ring shaped interference-type hydrodynamic rotary seal having waves on the lubricant side which provide increased film thickness and flushing action by creating contact pressure induced angulated restrictions formed by abrupt restrictive diverters. The angulated restrictions are defined by projecting ridges, corners at the trailing edge of the waves, or simply by use of a converging shape at the trailing edge of the waves which is more abrupt than the gently converging hydrodynamic inlet shape at the leading edge of the waves. The abrupt restrictive diverter performs two functions; a restricting function and a diverting function. The angulated restrictions cause a local film thickness restriction which produces a damming effect preventing a portion of the lubricant from leaking out of the dynamic sealing interface at the trailing edge of the wave, and results in a much thicker lubricant film thickness under the waves. This contributes to more film thickness in the remainder of the dynamic sealing interface toward the environment because film thickness tends to decay gradually rather than abruptly due to the relative stiffness of the seal material. Because of the angle of the abrupt restrictive diverter relative to the relative rotation direction, in conjunction with the restriction or damming effect, a strong diverting action is produced which pumps lubricant across the dynamic sealing interface toward the environment. The lubricant diversion is caused by the component of the rotational velocity tangent to the abrupt restrictive diverter. The component of rotational velocity normal to the abrupt restrictive diverter causes a portion of the lubricant film to be pumped past the abrupt restrictive diverter, thereby assuring adequate lubrication thereof.
This invention was made with United States Government support under Contract No. DE-AC03-90ER80939 awarded by the Department of Energy. The United States Government therefore has certain rights in this invention.