US Patent 7775528 Bi-directional pattern for dynamic seals

A bi-directional dynamic seal advantageously provides for the return of captured lubricant to the lubricant side regardless of a direction of relative rotation between the seal and the shaft. The seal utilizes a pattern of symmetrical pumping elements to facilitate the hydrodynamic pumping of the captured lubricant in response to the relative rotation. The symmetrical pumping elements have ending points that stop short of the seal edge of the seal. The seal may utilize secondary pumping elements that communicate with the primary pumping elements to capture lubricant that is not captured by the primary pumping elements.