Study of the characteristics of lip seals for gasoline

In this study, the life and reliability assurance of oil seals used for gasoline sealing was attempted. The determination of the life and reliability from the theory of sealing and the analysis of factors that determine a leakage showed that a change of sealing characteristics can be determined by using wear of a shaft and the deterioration of rubber material as parameters. Since sealing characteristics were closely related to the friction torque, leakage elements tests were performed by using a tester designed for precision measurements of the friction torque and the rate of leakage from a seal. Obtained results showed a clear relationship between the characteristic value Φ that expresses the friction force and the leakage rate and allowed the determination of the sealing limit value Φ. A method of the life and reliability assurance was verified by performing elemental tests by using a reduction of the shaft diameter by wear, a change of the shaft surface roughness, and the high-temperature deterioration of lip material as parameters.