A discussion of oil seal radial load and its influence on seal performance is presented. The radial load, lubricant and shaft speed interaction affects the friction horsepower and consequent temperature level at the seal lip. Since the oil seal mechanism is a temperature dependent phenomena, it is important to know and control lip temperature if optimum seal performance is to be achieved.
New research techniques are illustrated showing the measurement of dynamic radial load and lip temperature. The infra-red technique for observing lip temperature is discussed in detail. It is concluded that oil seal life, once considered a function of luck, can be analyzed today as a function of load.