Research On Key Technologies Of High-pressure Internal Gear Pump

Internal gear pump has advantages such as compact structure, smooth operation, highpressure, low noise, no trapping phenomenon, good self-absorption, wide speedrange,and is widely used in various of engineering machinery. The development tohigh-pressure is its trend. But with the increased pressure the friction,heat oil leakageand deformation of parts are likely to increased. In this paper, the key technologieseffecting high-pressure of internal gear pump were analyzed.Because of the hydraulic pressure and meshing force on internal gear in internal gearpump,the pressure of pump acted by the external wall of internal gear is great,leading tothe increased fiction between internal gear and pump,and the agglutination failure ofinternal gear and pump.In this paper,the key parameters such as the position and anglerange of the hydrostatic support’s channel were computed by theoretical analysis andFLUENT numerical simulation.The prototype experiment was done according to theparameters and the result of experiment verify its feasibility.There would be much leakage under high-pressure condition on the radial and axialface of gear in internal internal gear pump.To decrease the radial leakage the radialcompensation is needed.By the dynamic analysis of the force on crescents as the gearrotates,Under the conditions of the two stationary crescents stay close to the crest ofinner gear and external gear to form radial seal.The angle of the end of the abovestationary crescent in the high pressure area and the fixing angle of the seal stick of theleast resultant force was obtained by optimization.The axial leakage is compensated by the floating plate.Because of the unbalancedforce and moment on the two sides of floating plate,the floating plate wouldinclines,lead to the wear of the axial face of gears and floating plate.As a result,theservice life of gear pump would be reduced.For another,the force on the floating platedecide the volume efficiency,the axial gap and the leakage between the floating plateand the external gear,internal gear.The angle of boundary of back-pressure chamber andthe radius of internal,external cycle were obtained.There is gap between the internal components in internal gear pump,which leads toleakage under the condition of high-pressure and the resistance to the components.The leakage and resistance of components are relative to the roughness ofcomponents.Basedon the analysis of the effect of the leakage and friction of fluid causedby the roughness of components,the optimal roughness for the least leakage and frictionof fluid was determined.The external gear was deformed by the pressure on the radial face,which influencethe dimension and the flow rate of internal pump.The difference of the flow rate causedby the deformation of the external gear was obtained by regarding the deformation ofexternal gear as deflection coefficient.