The Effects of Non-Flatness on the Performance of Slippers in Axial Piston Pumps

All previous analyses of slippers in axial piston pumps have assumed that the slipper running surface was perfectly flat and have all failed to explain the satisfactory performance of these bearings. It has been suggested, however, that slippers in axial piston pumps may depend, for their successful operation, on the small deviations from a perfect flat of the slipper surface. This paper examines the relationship between such a non-flatness and the minimum film thickness produced under steady operating conditions. It is shown that a very wide range of slipper non-flatnesses can lead to satisfactory slipper performance and that the minimum film thickness predicted is remarkably insensitive to the actual amount of deviation from flat.