面向外啮合齿轮泵困油问题的健壮性设计

针对外啮合齿轮泵困油区压力高导致噪声大、低容积效率等问题,综合齿轮泵工作过程中内部流体动态特性,提出了面向齿轮泵困油问题的健壮性设计方法.以某型号高压齿轮泵为研究对象,建立三维流体模型,利用CFD专业软件PUMPLINX,基于全空化模型对齿轮泵内部流场进行解析,分析了该齿轮泵猫眼式卸荷槽结构参数、齿轮泵转速、负载压力以及介质特性对困油区压力的影响,并借助于试验设计和响应面函数方法建立了关于困油区压力的近似模型.最后,以困油区压力模型服从正态分布且均方差最小为目标,优化了猫眼式卸荷槽尺寸参数来减少转速、负载和介质特性对困油区压力的影响,并以随机分析方法验证齿轮泵困油区压力对不可控因素随机变化的健壮性,验证结果表明:随着不可控因素的随机变化困油区压力峰值对其敏感波动从健壮性设计前的40%缩小至健壮性设计后的18%左右,从而提高了泵的稳定性和可靠性. 

Robust design of external gear pump with trapped oil problem

Based on the fluid dynamic characteristics of gear pump, a robust design method was proposed to solve the large noise, low volume efficiency in external gear pump caused by high pressure of trapped oil. A type of high pressure gear pump was used as the research object, modeled and simulated by CFD professional software PUMPLINX. The effects on trapped oil pressure by cat eye type unloading groove structure parameters, gear pump speed, load pressure and medium characteristics were analyzed. An approximate model of trapped oil pressure was built based on the design of experiments and response surface function methods. Finally, in order to reduce the impact of uncontrollable of factors such as pump speed, load pressure and medium characteristics on pump performance, the robust performance evaluation model was built to optimize the cat type unloading groove structure parameters and achieve the trapped oil pressure model subjecting to normal distribution in the case of the minimum mean square error. Besides, with the change of random and uncontrollable factors, the robust performance of trapped oil pressure was verified; the result displayed that the trapped oil pressure peak before robust design fluctuated from 40% to 18% after robust design, so the stability and reliability of working pump were improved.