Formation of a fluid film between a valve plate and a cylinder block of piston pumps and motors. 3rd report. Fluid film sluctuation and loss power.

Abstract

As already pointed out, a valve plate with hydrostatic pads is able to form a fluid film between the valve plate and the cylinder block over a wide range of operating conditions. In this report, the fluctuation of the fluid film and the loss power on the sliding plane are analyzed, including both the change in the number of pistons on the high-pressure side and the trapping phenomenon. The parameters treated numerically are as follows: ratio of the hydrostatic-load-carrying capacity to the pushing force, shaft spring effect on the behavior of the cylinder block, number of pistons and the solid friction between the shaft and the cylinder block.