Measurements of Combined Frictional and Thermal Behavior in Journal-Bearing Lubrication

Abstract

Abstract Data were obtained in tests with a four-bearing friction machine which show that an increase in the load on a journal bearing produces a proportional increase in frictional torque when other conditions of test are held constant. Under these same conditions an increase in load also produces a proportional increase in the fluidity of the oil in the bearing. These two effects are the result of the combined hydrodynamic and thermodynamic actions involved in journal-bearing operation with forced-feed lubrication. The increase in torque is influenced by the viscosity of the oil, the oil-inlet temperature, the oil-feed pressure, the shaft diameter, the clearance-diameter ratio, and the length-diameter ratio. The increase in fluidity is influenced by the same factors and also by the speed of the journal. Empirical equations are derived for the fluidity-pressure relationship for certain conditions. Also, a graphical method is given for the use of this relationship in estimating safe bearing loads.