Abstract
This paper presents the experimental results of the friction characteristics of double liptype oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip, and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torques of double lip seals show 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double lip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.