새로운 기하학적 접근 방법을 활용한 연속 접촉 나선형 기어 펌프의 가변 동적 부하 예측

Abstract

Conventional involute gear profiles inherently suffer from trapped volume phenomena due to two point contact within the meshing region. This leads to discontinuities in the fluid flow and irregular torque fluctuations. To overcome this limitation, the present study introduces a novel hybrid tooth profile, which combines circular arc and involute curves, enabling continuous contact without trapped volume throughout the meshing cycle. A numerical model was developed to analyze the flow rate, torque pulsation, and axial thrust characteristics of a helical gear pump with this hybrid tooth design. Based on a rotational angle dependent meshing mechanism, the model calculates the time dependent variation of the fluid domain geometrically. The results indicate that helical gears exhibit significantly reduced flow pulsations compared to spur gears, promoting flow continuity and stability. A lumped parameter model was further implemented to reflect actual experimental conditions and assess pressure and flow behavior, validating the numerical results against theoretical predictions. Axial thrust analysis revealed that meshing induced axial forces act in opposite directions on the driving and driven gears, emphasizing the necessity for bearing design and mechanical compensation systems. The proposed continuous contact based numerical model demonstrated strong agreement with the actual pump geometry and flow characteristics, confirming its applicability to precision gear pump design. In particular, it offers a robust framework for analyzing transient torque and axial force responses caused by the intrinsic structural asymmetry of helical gears. Future extensions of this research may include the design of balancing mechanisms, line of contact analysis, and experimental validation to support broader implementation in high precision pumping systems.