RADIAL LIP SEALS EFFICIENCY UNDER DYNAMIC OPERATING CONDITIONS

This paper describes experimental and numerical procedures to estimate friction torque on a rotating shaft due to radial elastomeric seals. Two different test rigs have been built, in order to highlight the relationship between the overall friction and the local behaviour of each lip portion in presence of dynamic eccentricities. A direct measurement has been performed with a rotating shaft machine and results have been compared with the torque calculated as product of a global frictional coefficient and the normal stress on the lip surface. The latter has been computed by an improved FEM simulation which has been specifically optimized in order to evaluate the lip deformation due to mounting interference. Previous experimental results about radial and tangential oscillation of a limited lip region allowed to calculate the frictional coefficient as the ratio of the friction force and the force pressing the lip on the shaft surface.