| In recent years, Chinese have began to do the research of high-pressure internal gear pumps.But we lack research of internal gear pumps in parametric design, performance and other aspects of basic analysis.So there is a large gap between the current domestic internal gear pumps witn the products of foreign countries in output pressure, volumetric efficiency and the stability of the products.And China's internal gear pumps have low production and few species.In this paper,we mainly did the finite element analysis and optimizations for some main structures of internal gear pumps , which improved the overall performance of the gear pumps , reduced the use of materials and reduced the weight of the pump.So the pump could be used in some occasions,where mobility and portability were required. Finally,the actual deformation of shells of gear punps under different loads were measured.We first drawed the three-dimensional solid models of the main structures of the internal gear pump and the assembly drawing. Those draws were saved as the format of *.X_T,then they were imported into ANSYS.According to the finite element analysis of ANSYS software,the strength and stiffness analysis of shell of internal gear pump was done,finding the stress concentration zone and location of large deformation.The shell was optimized,ensuring the strength to meet the design requirement,which can improve the stiffness,improve the overall performance of pump,save material and reduce the weight of pump,which had better social and economic benefits.Then, the shells of internal gear pump of different materials were analyzed by ANSYS software. The shell of aluminum was analyzed,finding out the maximum permissible working pressure of this shell.And it was compared with the shell of dectile iron.Because of the different material properties, internal gear pumps of ductile iron are used in the high-pressure and medium-pressure cases,while internal gear pumps of aluminum are mainly used in the medium-pressure and low-pressure environments.The gear pump of aluminum can be used in the high-temperature and other extreme weather conditions.The weight of the optimized shells of two different materials both decreased by 7.4% than the original ones.The optimizations saved material. The strength of the shells changed very little,while the maximum deformation of ductile iron and aluminum decreased by 10.33% and 9.85%.The stiffness of the optimized shells was enhanced and the overall performances of the pumps were improved.,indicating that the structural optimizations of the shells were reasonable. The method of finite element analysis by ANSYS can also be extended to other shells of different materials for analysis and comparison to determine the maximum working pressures of them.The ring gear of the internal gear pump was analyzed for intensity.We could draw the conclusion that the pressure of high pressure oil chamber made the deformation of the ring gear,then the tooth root stress was very large.So the ring gear was easily broken. Therefore,we should improve the machining precision of the outer surface of the ring gear and the inneral surface of the shell.This method of analysis and optimization also has an important significance to design and analyze other parts of pumps,which can make the pump have the best overall performance.Also this method provides the analytical basis for internal gear pumps of different models and different pressures. This method of analysis,optimization and experiment also has an important significance to develop the whole series of new gear pumps of different materials. |
