Study On Key Technology Of Design And Exploitation Of Internal Cycloid Pump With Multiple Tooth Difference

As an important part of the mechanical transmission device,The gear pump is widely used in the domain of the hydraulic drive and control technology. And the internal cycloid pump has been paid high attention in the related industries, since it has so many advantages such as large displacement, high volume efficiency, small fluctuation of flow rate, compact structure and so on. In-depth study of the key technology of the internal cycloid pump, for example, profile design, optimization, simulation and manufacture, is very significant for the development and innovation of the gear pumps.Taking the internal cycloid pump with multiple tooth difference as the researching object and starting with analysis of the parametric equation for the curtate epoicycloid, the curve equation of the cycloid gear’s profile is deduced through the relative motion method and envelope method in this dissertation. The basic parameters and the geometric dimensions are summarized and at the same time, the constraints for the geometric parameters are discussed, the meshing characteristics and the kinetic characteristics are further analyzed, including the meshing angle, contact ratio, meshing limited point, profile curvature radius and relative sliding coefficient and so on.The optimization model is established in which the displacement in unit volume is taken as the objective function, with contact ratio, meshing angle, gear tooth profile interference as the constraints and arc radius index, generate index, tip radius index, dedendum radius index as the design variables. With the MATLAB software, the GUI interface is programmed which makes the optimization design convenient and efficient. The analysis and compare for the flow characteristics of the gear pumps before and after optimization are worked out, which proves the result of the optimization rational.With the method of finite element simulation, the fluid simulation (CFD) and fluid structure interaction analysis (CFX) of the model after optimization are carried out. The moving-grid technology is used in the fluid simulation, and together with the flow field distribution of the gear pump, the rule of the flow field changing under different rotor speeds or fluid viscosities are analyzed. The fluid structure interaction analysis is carried out to analyze the mutual coupling between the inner components and the fluid, in order to study the stress and displacement of the gears and the key components, which provides a theoretical basis for the profile modification of the gears. After the discussion about method of the finish machining for the gears, the grinding method is chosen and the advantages and disadvantages of the generative grinding and the form grinding are analyzed due to different situations, after that, the design shape of the grinding wheels are provided. In the end of this dissertation, the profile modification of the tooth-form is studied and the corner correction method is finally chosen. In order to improve the driving conditions, only one of the gears (inner or outer) has to be modified, considering which is easy to be done.The study of the internal cycloid pump with multiple tooth difference includes the design of the profile curve of the cycloid gear, the optimization of the basic parameters of the gears, the compare of the characteristics of the pumps, the finite element simulation of the model, the finish machining method and the modification of the tooth-form. A study system about the cycloid pump is almost finished in this dissertation, which can provide the theoretical basis for the manufacture and further research of the internal cycloid pump with multiple tooth difference.