Design of a new type of internal meshing gear pump with variable clearance and fewer teeth

Transient simulation analysis of internal meshing gear pump with fewer teeth shows that the backfilling phenomenon during operation will lead to pressure spikes in part of the teeth cavity pressure, affecting the coefficient of uneven flow, and the main cause of this issue is attributed to the improper design of the gap between the teeth and the crescent. In this paper, the influence mechanism of tooth-crescent clearance on the flow rate and the coefficient of uneven flow is analyzed, based on which a new variable clearance internal meshing gear pump with fewer teeth is designed. Through comparative and analysis with traditional gear pump in terms of flow rate, dimensionless number, cavitation effect, and peak chamber pressure, it is confirmed that the proposed variable gap design has advantages such as less flow leakage, lower coefficient of uneven flow, smaller pressure loss, reduced cavitation phenomenon and lower peak pressure, which provides a new reference for the design of internal meshing gear pump with fewer teeth.