New application areas such as compact drives and
displacement control using variable electric motors require
that hydrostatic machines exhibit good performance also at
very low relative speeds without being damaged during
critical mixed friction conditions. Low relative speeds result
in a drop of the hydrodynamic pressure in the lubricating gaps
and therefore to friction losses, wear and a higher probability
of failures. The aim of this paper is to present a novel
approach to reduce the viscous friction losses and wear
during critical operating conditions, by increasing the
hydrodynamic pressure build-up and modify the hydrostatics
of the slippers of an axial piston pump. To achieve this goal
structured surface profiles on the slipper surface are
investigated, both in simulation and measurement. The
measurement results and simulation validation are shown in
this paper.