In many machine elements working in the elastohydrodynamic lubrication regime the components are subjected to low amplitude oscillatory motions, which disturb the conditions for optimum formation of the lubricant film. Most of these applications involve combined vibrations in both vertical and longitudinal directions. For example, in gears and rolling element bearings vertical vibrations may be caused by changes in load, speed or geometry at the contact point, while the longitudinal vibration is often a direct result of the torsional vibrations of the shaft. Vibrations also transmit to these machine elements from other parts of the assembly or from the surrounding environment. Vibrations are usually harmful because they reduce the accuracy of motion and may impede the formation of a lubricant film, thus affecting the durability of machine components.The aim of this is study is to investigate the behaviour of EHD films during lateral oscillatory motion using the optical interferometry technique
