Analytical model of the pressure variation in the gerotor pump chambers

Abstract

In this paper the operating characteristics of the gerotor pump with fixed gear axis are described. Gerotors are used as motors, compressors and expanders, as well as in the new ecological and economical star rotor engine. The subject of the investigation is the internal combustion engines lubricating pump and the possibilities for the new construction solutions with better characteristic with the aim of increasing the pump energy efficiency. The basic objective of this investigation is the definition of the relation between the single geometrical parameters and the values of the pressure variation in the pump chambers as the consequence of the change of the chamber’s current volume. On the basis of the geometrical-kinematical model of the pump gear profile, the determination formula of the chamber’s current volume and the corresponding pressure variation are defined in this paper. The derived analytical formulae and graphical interpretation of the obtained results which are given in the paper open the possibility for the analysis of the influence of the gearing geometrical parameters on the variation of the instantaneous pressure. The obtained results can be used for the calculation of the precise values of the forces and torques affecting to the gear pair of gerotor pump, as well as its volumetric losses. The objective of the solution choice is obtaining the best design of the gerotor pump ith minimum energy losses.