Abstract
A bouncing ball apparatus was manufactured aiming at measurements of shear strength of a lubricant film under a higher pressure than 2GPa. The principle of the measurements is that the normal load and the tangential forced were simultaneously determined with the three component sensor. Experiments were conducted as a parameter of the impact angle under a room temperature. As the impact angle was increased, the coefficient of friction first increased and then it leveled off. The coefficient of friction measured with the bouncing ball apparatus agreed with the extrapolated curve based on the coefficient of traction determined with the disk on ball type EHL tester.