Study On The Structure And Performance Optimization Of The Large Displacement Gear Pump

The gear pump is a volume type liquid delivery pump to apply in the most widespread situation. It has many merits such as the size slightly, the weight light, the manufacture easy, the work reliable, the price inexpensive, to the fat liquor insensitive, self-absorption ability strong, maintenance convenience and so on.But its output pulsation is obvious, the trapping oil is serious, the displacement is small. which have limited its application situation. In order to expand its application scope, this thesis proposed one kind of new structure gear pump based on the gear meshing theory. The changed trapping oil is reduced obvious.The structure of normal gear pump has changed in the new gear pump, by assembling two different module gear, so as to separate function of change of the working capacity from function of the movement and power transmission. After separating, the output capacity is increased by more two times than that of normal straight gear pump on the same condition of volume.During the design of new product, the flow property of gear pump is studied in detail. The formula of calculating instantaneous delivery and flow pulsation is deduced,the question of trapping oil is studied deeply and the formula of calculating change of volume of gear pump's trap oil. The mathematical model of the gear pump's optimum design is built. The form of gear tooth is designed accurately by the parameter modeling function of ANSYS software, and the parameter meshing simulating model is built, which is useful for the design of serial gear and the standardization design of similar part. The structure and the stress of the gear pump are analysed by Finite Element Method, and based on the optimum design function of ANSYS software and completed the aim function with the minimum displacement per volume, the optimum design of pump structure is realized, which makes the volume of the gear pump body smaller and the structure more reasonable and effective and solves the problem of traditional design with experience. Studied on the clearance between the new model gear pumps and the leakage, the dual element flowing leakage model of the clearance at the radial and axial direction is built and the calculating formula of optimum clearance is deduced.In order to make it convenient for comparing performance with existing gear pump, this paper uses CBG3200 gear pump produced by Liansheng hydraulic Industrial Co.Ltd. to compare with. The result of optimum design indicates that the displacement per unit volume of new gear pump decreases by 58% and the changed volume of trap oil decreases by 29%.The large displacement gear pump studied in the paper has good market, and it is very useful for reference when calculating the strength and optimizing the structure in the similar part.