Effects of Interlip Pressure of Reciprocating Seals with Two Lips on Sealing and Frictional Characteristics

The sealing and frictional characteristics of three types of nitrile rubber lip seals having two lips are examined under sinusoidal reciprocating conditions. The results obtained are explained by applying the inverse hydrodynamic lubrication theory. It is found that the oil is accumulated between the two lips and a positive interlip pressure is produced, resulting in a decrease in the friction force. The magnitude of the interlip pressure depends on the contact pressure distribution. It is also found that such reciprocating seals maintain low values of the frictional coefficient even under high sealing pressures. This is because the interlip pressure increases with increasing sealing pressure.