Research Of Pilot Pressure Valve Self-excited Vibration And Noise

Hydraulic components vibration is the roots of disrupt system normal work in hydraulic. Self-excited vibration is main one of the three pilot pressure valve's vibration. The self-excited vibration and noise of the pilot pressure valve generated mainly by pilot valve. So it is very important to carry out self-excited vibration of the pressure valve.In this paper, conical structure model of the pilot valve spool has been established by analyzing the structure of the pilot pressure valve characteristics. The factors influenced pilot valve stability was studied, the pilot valve's stability was judged in use of Bode criterion. The open-loop system of the examples in this article of is stable, and the closed-loop is instability. And the spool induced vibration by fluid flow has been studied on theory base on fluid influence the spool. The simulation analysis of flow field has been made in different parameters of the valve cavity and the conclusion of Front chamber of the pilot valve orifice 0.001mm and the pilot valve eccentric valve port is not conducive to export close to the stability of the pilot valve has been obtained. The simulation of pilot relief valve was made and Pilot spool vibration frequency characteristics has been obtained. And another conclusions as follows: the pilot spool vibration frequency are between 100Hz to 1500Hz and the maximum amplitude peak occurs around 500Hz , the second largest amplitude peak appears between 700Hz to 800Hz, followed in the 100Hz to 300Hz and 500Hz to 700Hz frequency band vibration amplitude volatile .The relief valve body's modal analysis, harmonic analysis was been made and some conclusions as follows: he more body connection stiffness constraints higher the better the stability of the pressure valve; Resonance peak appears in the 600Hz when constraints in and out of the oil port, and the first natural frequency is 638Hz on this conditions; The valve body first natural frequency is higher when three out of the oil port constraints, and Excitation amplitude of vibration increases with frequency increasing in the 0 ~ 1200Hz frequency band and no resonance peak.The Y-10B pilot relief valve self-excited vibration and radiated noise were tested, vibration and noise radiation characteristics has obtained under different pressure, The vibration of relief valve increase with the pressure increasing, the peak frequency of body vibration Increased and the noise radiation intensity increases.