A “radial oil seal” or a “rotarylipseal” is commonly used to
prevent leakage and reduce friction (Fig. 1) This seal family keeps
oil on the rotating shaft,and dust particles outside. It consists of an
elastomeric lip bonded to a rigid case and a garter spring that
compensates for changes in the rubber properties due to heat or to
chemical attacks. Typically , the inner diameter of the seal is
smaller than the shaft outer diameter so that when the seal is
installed , the lip creates a static force applied to the shaft.
A successful rotary lip seal operates by forming an oil film
between surfaces of the lip and theshaft [1]. Indeed , the lip
asperities induce a load support due to the rotating shaft which
keeps the lip separated from the shaft.Inaddition , these asperities
affect significantly the sealing mechanism and,namely , the leakage flow and friction.
According to the literature , the lip roughness produces a
reverse pumping action , which tends to pump a liquid from the
air-side of the seal toward the liquid-side , opposed to the leakage.
This flow is strongly depending on the lip roughness [2] or micro-undulations [3,4] and the lip elasticity. Well-designed rotary lip