大侧隙外啮合齿轮泵的困油特性和流量特性
The Trapped Oil Characteristics and Flow Characteristics with Large Backlash Gap in External Gear Pumps

以对称双矩形卸荷槽为例，基于泵排油区域封闭容积变化的精确计算和困油压力的仿真结果，给出了理想状态和实际状态下瞬时流量的计算公式，并就流量品质进行分析。结果表明：理想状态下，卸荷槽能有效改善泵的流量品质，平均流量提高了1.6%；流量不均匀系数降低了65.3%；实际状态下，卸荷槽同样能有效改善泵的流量品质，不过改善效果将有所下降；大侧隙时两困油区互为一体仅为一种粗略的近似；单齿啮合区间也会发生明显的困油现象等。得出困油现象仅限于双齿啮合的传统定义应予以修正，以及在流量计算中考虑困油压力很有必要的结论。
With double symmetrical rectangle relief grooves as an example, from the accurate calculation of closed volume changed in discharge side of gear pump and the simulation results of trapped oil pressure, the calculation formula of instantaneous flow rates were derived under ideal state and actual state, and then the flow quality was analyzed. Results indicated that, in the ideal state, the flow quality was greatly improved by relief groove, the average flow rate was increased by 1.6%, and the non-uniform flow coefficient was reduced by 65.3%; in the actual state, the flow quality was also improved by relief groove, but the improvement effect was slightly declined; the two trapped oil regions as a whole in large backlash gap only was a rough approximation, and the obvious phenomenon of trapped oil was also occurred in the meshing range of a single tooth, etc. It is summarized that the classic definition of trapped oil phenomenon limited in the meshing range of two teeth should be corrected, and it is necessary to consider the trapped oil pressure in the calculation of instantaneous flow rate