| Gear pump is a traditional industrial pump, which acts as a power unit for hydraulic actuators to provide working pressure and can be used to transport liquids, so it is still widely used in modern industry. With constantly update of computer aided software and intelligent NC machine tools, people are paying more attention to living environment and working efficiency. Traditional gear pump has low working pressure, large flow ripple, loud noise and low volumetric efficiency, which has severely limited its application and development, so experts from home and abroad are undertaking an in-depth research of these properties. Among them, high pressure helical rotor pump has strong representation, not only because of its less complicated structure and less sensitivity to oil pollution, but also because of its higher working pressure, smaller flow ripple, lower noise and higher volumetric efficiency. Domestic theoretical researches on high pressure helical rotor pump and relevant designs of complicated tools have already existed, but their research methods are limited and theories are not very realistic so that their conclusions need consideration.This paper took high pressure helical rotor pump as research object. First, tooth profile curves of driving and driven bars was introduced. Based on plane meshing theory and coordinate transforming method, using mathematical expressions of vectors and rotation matrices, formulas of pump linear equations and meshing equations were deduced. Referring to actual parameters, a set of tooth coordinates and a single tooth profile were derived. Since the requirement for continuous one-dot contact of driving and driven bars was ensured, trapped oil phenomenon with traditional gear pump was dispelled in gear structure. Second, gear rotor helicoid was discussed in detail and based on space meshing theory, the mathematical model of working piece and cutting tool was established. With the usage of motion analysis method, contact condition was created. Then in the mathematical expression form of vector, helicoid equation of gear rotor and forming milling cutter, helicoid normal vector, characteristic equation and contact line equation were completely deduced. With the usage of least square method, numerical solution of line equation was achieved. Next, the calculation of cutting tools edge coordinates and the drawing of cutting tools axial outline were completed. Third, based on characteristic parameters of traditional gear pump, limited formula conditions of high pressure helical rotor pump such as contact ratio, theoretical flow, flow rate and inlet-outlet size were deduced. And with the consideration of actual requirements, the characteristics of the pump were calculated and analyzed. On the basis of theoretical researches above, parameterized design software for rotor profile and cutter edge based on MATLAB GUI was developed, including interface design and main program design, so that users can easily making appropriate selection for essential design parameters of rotor profile and corresponding cutter. What's more, three-dimensional parameter modeling of driving and driven gears was carried out by utilizing engineering software Solid Works, along with interference check for driving and driven gears and structural design and test of integrated tools. In the end, the actual machining of drive gear and driven gear in cooperative industry verified the accuracy of the theoretical calculation results.To ensure the using security and working stability of high pressure helical rotor pump, researches on force analysis and pump performance test still can be done in the later period, such as utilizing software ANSYS to do force analysis, contact analysis and modal analysis of its gear meshing and thickness of pump wall, and designing special test bed to do experimental analysis and data collection of working pressure and flow ripple, etc. |
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