变排量外齿轮泵的内流场仿真分析及卸荷槽优化

Unloading Groove Optimization and the Inner Flow-field Simulation Analysis of the Variable Displacement External Gear Pump

建立了变排量外啮合齿轮式机油泵的CFD模型,采用定量分析方法分析变量泵的内流场特性,通过流量仿真结果与实验结果的对比,验证了模型的正确性。研究得出变排量外齿轮泵的啮合齿宽公式,分析机油泵困油区域的压力波动规律,提出了在泵从动齿轮活塞上端开楔形卸荷槽的优化方案,有效减小了困油区域的压力波动。结果表明,通过卸荷槽优化,在保持流量不变的前提下,使吸油腔和排油腔压力波动分别降低了12.3%和8%。所做工作可为变排量外齿轮泵的设计开发提供技术支持。

A CFD model of a variable displacement external gear pump is established.The quantitative analysis method is applied to analyze characteristics of the pump inner flow field.The accuracy of the established model is verified by comparing the flux simulated and corresponding tested data.The tooth width formula of gear meshing is obtained.Through oil pressure analysis in the trapped oil area,an optimization scheme with a wedge-shape unloading groove added at the upper piston of the driven gear is proposed,which effectively reduces the pressure fluctuation of trapped oil area.The study results show that,under the condition of the same pump flux,the optimized unloading groove can reduce the pressure fluctuations in the suction and discharge chambers by 12.3% and 8%,respectively.The work is helpful for design and development of the variable displacement external gear pump.