Study On Critical Speed Mechanism Of Rotor System Of High Speed Aviation Axial Piston Pump

With the increasing pressure of aircraft hydraulic system,higher requirements are put forward for the performance of the aviation pump.The aviation pump depends on imports.The purchase and maintenance are expensive.The order cycle time is long.It seriously restricts the development of domestic large aircraft industry.With the development of avi-ation pump toward high speed,high pressure and high power to weight ratio,its vibration becomes more serious and its failure rate increases.Therefore,it is very important to study the vibration mechanism.The rotor dynamics theory is used to analyze the critical speed vibration mechanism and its influencing factors of a certain type aviation pump.It is of great significance to improve the speed of pump,master the design optimization method of high-speed aviation pump,and realize the localization of aviation pump.The main re-search contents are as follows:(1)The 11-plunger high-speed aviation pump is taken as the research object and the rotor system model of the aviation pump is established by extracting its rotating parts.According to the equivalent principle of complex rotor system,the lumped mass model is established.The critical speed is solved by the transfer matrix method.In the ANSYS Workbench software platform,the model of the actual aviation pump rotor system is es-tablished,and the critical speed is analyzed.In addition,the critical speed test is complet-ed on the experimental platform.The transfer matrix method is used to analyze the critical speed of the experimental rotor model,which further verifies the correctness of the meth-od used.(2)The parameters such as bearing support stiffness and axial supporting position are modified.The critical speed of the rotor under different parameters is analyzed by transfer matrix method and finite element method respectively,and the influence of each parame-ter on the critical speed is explored.Among them,the support stiffness of the two bearings varies in the range of 1×10~6~1×10~7 N/m,and the parameters of the axial supporting po-sition depend on the structure of the pump drive shaft.Based on the above analysis results,the optimum parameters of support stiffness and axial supporting position are given.(3)The rolling bearing is an important part in the aviation pump rotor system.The accurate calculation of bearing stiffness has a great influence on the critical speed.Aiming at the cylindrical roller bearing in the aviation pump rotor system,its comprehensive stiffness is analyzed theoretically.The influence of different bearing structure and working conditions on the comprehensive stiffness is studied,which provides theoretical support for the subsequent calculation of the comprehensive stiffness of various cylindrical roller bearings.It also provides guidance for the selection of aviation pump bearings.The reasonable and effective measures are put forward to improve the critical speed of the rotor system.The research results lay a theoretical foundation for improving the performance of high-speed aviation pump.