The Optimal Design in External Gear Pumps and Motors

To improve the system performance of hydraulically assisted mechatronic systems, the research investigates the instantaneous pressure of the meshing action in the external gear pumps and motors. The undesired large pressure overshoots or spikes could be excited by virtue of the sudden volumetric change of meshing pockets. In practice, the spikes cause the gear machines to be noisy, inefficient, and have fatigue problems. The study employs the optimization theorem to analyze the nonlinear dynamical equations to define the instantaneous flow area overlapped by the wear-plate profiles and control volumes. The approach can also be applied to determine the backlash area to avoid large pressure variations between two meshing volumes. System noise may consequently be reduced and the mechanical efficiency is improved in gear machines. However, the volumetric efficiency may be compromised. Thus, all these issues have to be considered to achieve the optimal design.