Surface Nanostructured Coating for Improved Performance of Axial Piston Pumps

The work starts from the consideration that most of the power losses in a hydrau-lic pump is due to frictional losses made by the relative motion between moving parts. This fact is particularly true at low operating velocities, when the hydraulic lift effect must however be able to maintain a minimum clearance in meatus to limit the volumetric losses. The potential of structured coatings at nanoscale, with super-hydrophobic and oleophobic characteristics, has never been exploited be-fore in an industrial application. The work studies the potential application of nano-coating on piston slippers surface in a real industrial case. The aim is to de-velop a new industrial solution to increase the energetic efficiency of hydraulic pump used in earthmoving machines. The proposed solution is investigated using a dedicated test bench, designed to reproduce real working conditions of the pump. The results show a reduction of friction coefficient while changing working pressure and rotation velocity.