Influence of axial direction on performance of biomimetic sealing system

A biomimetic bearing seal system has been developed to reduce frictional loss and improve the separation of air and water. The seal mimics the material properties and mechanical characteristics of articular cartilage found in natural synovial joints. It is made of the hydrated material polyvinyl formal (PVF), which has a porous structure, high wear resistance, and exhibits low frictional resistance when lubricated with polyethylene glycol. The analysis presented assesses the effectiveness of this shaft seal system and standard oil seals in two different shaft configurations (horizontal and vertical) to evaluate the effects on the torsional resistance and sealing ability. It is shown that PVF seals have a lower initial torque and a higher wear resistance in comparison with oil seals in both configurations. The average torque measurements were lowest in the horizontal configuration PVF seal. In the vertical configuration, the upper (toward air) PVF seal suffered from a reduction in lubricant, which was thought to be caused by settling in the lubrication reservoir, thereby slightly increasing the average frictional resistance. To maximize the system performance, the sensitivity of the frictional property to the axial direction should be considered.