Experimental investigation of load carrying capacity and frictional torque of dimpled parallel thrust bearings

This study involves experimental investigations of the hydrodynamic lubrication performance of dimpled parallel thrust bearings. Circular and rectangular dimples were created on lubricating surfaces and the hydrodynamic effects were evaluated. The load carrying capacity and the frictional torque were measured at a constant film thickness. The lubricating surface was observed to make clear the effect of the cavitation area on the load carrying capacity and the frictional torque. The circular dimple produced the highest load carrying capacity in all experimental conditions tested. The frictional torque for all dimpled specimens was lower than that of the dimple-free specimen especially at higher rotational speed. At lower rotational speed, cavitation did not appear and also the load carrying capacity did not generate. Cavitation emerged at the leading edge of each dimple as the rotational speed increased, and the growth of its area was dependent on the shape of dimples. The cavitation size of the circular dimple remained constant at the rotational speeds used in the tests, whereas those of the rectangular dimples linearly increased.