Optimization Design Of Low Noise Shell Structure For Piston Pump

Hydraulic system with its high power density ratio,flexible and convenient advantages in construction machinery,walking machinery,aerospace and other fields have been widely used.In recent years,with the technical progress and environmental protection more and more strict requirements,the hydraulic transmission system noise requirements are becoming higher and higher.As the power source and the main vibration source in the high pressure hydraulic system,the noise level of the piston pump has become one of the important parameters of performance.The shell is the carrier of the dynamic force and the medium of noise transmission in the piston pump.At present,the research on fluid noise of rotating body is more concentrated in China,and the research on vibration and noise reduction of shell is relatively few,which has a big gap with foreign countries.Based on the above background,two shells of different series of A10V45 specifications of Rexroth company are used as the research basis.By analyzing the internal excitation frequency and excitation load of the piston pump,the research of shell structure modal analysis and harmonious response analysis is carried out to find out the mapping relationship between the structural characteristics of the piston pump shell and vibration.It provides direction and theoretical basis for the structural optimization design of small vibration piston pump shell.The main contents and relevant conclusions of this paper are as follows:(1)The internal excitation source of piston pump is analyzed,and the principle and suppression of vibration are analyzed.The internal excitation source of piston pump is studied to determine the excitation frequency with large amplitude.Numerical calculation of excitation frequency of rotating mechanism in pump provides parameters of excitation frequency for harmonic response analysis.(2)The dynamic analysis and simulation of the axial piston pump are carried out.The displacement,velocity and acceleration of the plunger as well as the position of the plunger ball and the center of gravity are analyzed and calculated accurately.Precise numerical calculation of centrifugal force,radial force and lateral force of bearing bush on piston pump rotor is carried out,which provides the load value and position parameters of shell excitation source for finite element simulation.(3)The simulation analysis and comparison of different structures of the shell,based on the finite element method for shell analysis and calculation,completed the axial piston pump shell,back cover of the statics analysis,modal analysis and harmonious response analysis;The modal parameters and amplitudes of two types of plunger pumps with identical internal structure and identical working conditions are compared and analyzed.After optimization,stiffeners were added in the direction of vibration mode,which effectively increased the modal frequency of the shell,and the amplitude of the excitation frequency was effectively reduced,which was consistent with the actual situation and verified the correctness of the theory.(4)The results of excitation frequency were verified experimentally,and an experimental platform was designed and built.The vibration frequency of axial piston pump was measured by multi-channel vibration analyzer,and the measured data were analyzed and processed.The numerical results of excitation frequency of piston pump excitation source are compared with the experimental results,and the correctness of the calculation of excitation frequency is verified.