Study Solving The Trapped Oil Phenomenon In Gear Pump

Gear pump has a lot of unique advantages such as the structure of small size, lightquality, simple working principle, convenient maintenance, high self-priming abilityand strong ability to fight pollution.It is the "heart" of the hydraulic system and powerelement’s first choice.In practice,gear pump has irreplaceable function. But because ofits working principle, gear pump will produce trapped oil phenomenon. This limits thescope of application of the gear pump. Open unloading groove is the commonly usedmethod to alleviating pump trapped oil. This topic is for unloading groove’soptimization design.This paper introduces the principle of gear meshing and trapped oil.Puts forwardvirtual measurement method of the pump’s trapped oil area based on Pro/e5.0and themathematical model of trapped oil area. Contrast measured value and the calculatedvalue and mutual verification. We can get velocity distribution and pressure distributionof the pump cavity by gear pump’s flow field simulation.According to the trapped oilarea and trapped oil pressure’s changes, author puts forward four kinds of unloadinggroove’s design scheme.One-sided unloading groove is better than others. Only openunloading trough in the side of discharge cavity cooperating with gear tooth’s unloadingdecompression tank.The method of unloading trough improvement design can be used as a designmethod for design workers and validation method after completion of the unloadingtrough design.