高压渐开线内啮合齿轮泵轴向泄漏分析

Analysis of axial leakage in high pressure involute internal gear pump

为研究高压渐开线内啮合齿轮泵的内泄漏,尤其是轴向泄漏问题,对齿圈与泵体间隙处的轴向泄漏通道进行分析,并建立相应的简化模型,应用Fluent软件计算得到通道内压力沿周向分布的规律,采用所得公式与参数对轴向泄漏进行计算分析,并通过试验进行验证.研究结果表明:高压渐开线内啮合齿轮泵在采用间隙补偿机构时,进出油方式由轴向变为径向,从而导致了轴向泄漏;轴向泄漏与其他途径的泄漏相比更大,是影响该结构泵容积效率的主要因素,轴向泄漏的大小主要取决于齿圈与泵体公差的选择,配合间隙越大,轴向泄漏越大;同时,轴向泄漏也受齿圈偏心率的影响,泄漏量随偏心率的增大而减小.经分析得知,为保证泵在高压下能够保持一定的容积效率,在设计时需要严格控制齿圈与泵体双边间隙的上限值.同时,通过合理的径向力平衡设计控制偏心方向,可以有效利用高压下偏心率的变化缓解一部分轴向泄漏.

In order to study internal leakages,especially axial leakage,in an involute internal gear pump with high pressure,the flow in the gap channel between gear rim and pump casing,i. e. the axial leakage,was analyzed,and a simplified geometrical model was established. The pressure distribution along the circumferential direction in this channel was got by performing numerical simulations in Fluent. Based on that,the axial leakage flow rate was calculated,and validated experimentally. It was shown that the axial leakage is significant and it is the main factor that influences the volumetric efficiency of the pump. The flow rate in the axial leakage depends on the tolerance and eccentricity;moreover it increases with increasing clearance,but decreases with increasing eccentricity. In order to make sure the pump can maintain a high volumetric efficiency under a high pressure,the size of the gap between gear rim and pump casing should be controlled strictly in design phase. Meanwhile,the direction of eccentricity should be controlled carefully by figuring out a reasonable design for the radial thrust balance device. As a result,a part of the axial leakage flow rate can be reduced as well by making use of change in eccentricity under a high pressure.