PREDICTION OF HOUSING WEAR-IN IN EXTERNAL GEAR MACHINES CONSIDERING DEFORMATION EFFECTS

Initial housing wear-in is a key process to ensure high overall efficiency in most of the high-pressure (up to 300 bar) external gear pumps and motors. The internal housing profile that results from the penetration of the gears during the initial wear-in directly affects the volumetric efficiency of the pump or motor in operation. Therefore, an accurate prediction of such wear and its related effects is an essential aspect for a simulation tool for external gear machines. However, current state-of-the-art tools either neglect this aspect or make heavy simplifications. This paper presents a new simulation approach for modeling wear-in developed within the Multics-HYGESim (HYdraulic Gear Machine Simulator) tool. The approach leverages the previously developed model to determine the radial micromotion of the gears, and it includes the aspects of the deformation of both the bushings and housings present in the unit. The paper considers the case of a 22 cm(3)/rev unit as a reference, for which detailed simulation results, including the quantification of the wear-in and its consequences on the unit efficiency, are presented. The proposed approach is validated by comparing with experimental measurements the wear profiles and unit efficiency.