Establishment And Analysis On A Jet Pipe Servovalve Mathematical Model

Jet pipe servovalve is widely applied to hydraulic control systems with the requirementof reliable performance and stable operation due to the advantages of strong resistance abilityto the effects of contamination, higher efficiency of the pilot stage. However, the fluid flowcharacteristics in the pilot stage are extremely complex and the structure of torque motor isvery precise, so the characteristics of jet pipe servovalve are not easy to forecast result fromlack of complete mathematical model. Therefore, the research and design of jet pipeservovalve mainly depend on previous experience and a large amount of trial. This paperdevelops whole mathematical models by the numerical simulation method and provides areference for model improvement and optimal design of jet pipe servovalve.The basic structure and working principle of a jet pipe electrohydraulic servovalve oftwo stages with force feedback on the second stage were introduced and the basicmathematical formulae of each link were deduced. By the method of Fluent software, thestatic characteristics of the pilot flow field model were solved, the distribution and changeregulation of fluid pressure, fluid speed and gas content were presented and analyzed. Theinfluence of the supply pressure, drain pressure, the diameter of receiver hole, the distancebetween nozzle and receiver, the angle between the two receiver holes, the distance betweenthe receiver holes on the pressure characteristics and flow characteristics were discussed.The finite element model of torque motor was established by Adina software. The mainstress and deformation fields were analyzed, the synthetical stiffness of flexure tube and thestiffness of feedback spring were solved and the the relation curve between the nozzledisplacement and the applied force on the armature components, the relation curve betweenthe displacement of feedback rod and its applied force were present. By the modal analysis ofthe torque motor, the first6orders natural frequency and mode shape of torque motor wereobtained and the main vibration mode were stated.The major function curves were fitted to the corresponding mathematical equationsaccording to the solved key parameters of above links. In combination with the other basicmathematical formulas in this paper, the whole mathematical model of a jet pipeelectrohydraulic servovalve of two stages with force feedback on the second stage was established in the AMESim software based on the principle of bond grap. The flow responsecurves of the jet pipe servovalve were showed under several kinds of input signals, theinfluence of main parameters on its dynamic response characteristics was analyzed.The whole mathematical model of a jet pipe electrohydraulic servovalve of two stageswith force feedback on the second stage was established by numerical simulation softwaresuch as Fluent, Adina, AMESim, this model can simulate static and dynamic performance ofthe servovalve under different structural parameters. The modeling process provides areference for product design and research of the jet pipe servovalve, improves the researchand development efficiency of new products, and have a certain study significance for otherkinds of electrohydraulic servovalve simulation.