Design of gerotor oil pump with new rotor profile for improving performance

摘要

The rapid growth of the automotive and engineering machinery market activates the development of gerotor oil pumps with higher performance. In this paper, a new theoretical tooth profile is proposed. By replacing the constant length of the semi-major axis of an ellipse with a variable related to angle and using the profile normal method, the new profile is derived and illustrated. Then, the clearance of the profile is also discussed by considering the transmission characteristics and specific sliding of rotors. The analysis in this paper shows that the new profile could increase the average flow rate of the pump in low-speed condition, reduce wear, and experience lower fluid resistance on the inner rotor. The significantly increasing pressure ripple in high-speed condition also suggests that a relief groove needs to be redesigned to mitigate this phenomenon. The design idea can serve as a reference in further development of gerotor pumps.