Research On Poppet Valve Dynamic Response Characteristics

Hydraulic poppet valves are widely used in various hydraulic systems because of their advantages such as simple structure,good sealing,and strong flow capacity.However,the low-damping nature of the "spool-spring" makes the poppet valve system less dynamic and prone to vibration.When the poppet valve is working,the poppet valve core is suspended in the liquid flow.When the hydraulic system is disturbed,the spool deviates from the equilibrium state and enters the unstable state,causing the poppet valve to vibrate.The poppet valve vibration affects the control accuracy and stability of the hydraulic system.In severe cases,the hydraulic control system can cause failure or component damage.In recent years,with the high-pressure,high-speed and high-power hydraulic technology,engineering applications have imposed more stringent requirements on the performance of poppet valves.Therefore,research on the vibration response characteristics of hydraulic poppet valves has important practical significance.In this thesis,the vibration signal acquisition system and the valve core vibration image acquisition system were established.The dynamic response characteristics of the poppet valve were studied by the combination of theoretical analysis and experimental analysis.The dynamic response parameters of the poppet valve response signal were extracted and different working parameters were studied.The main conclusions are as follows:(1)The variation of dynamic response parameters at different inlet pressures and the effect of inlet pressure on the dynamic response of the spool are analyzed.The result shows that: With the increase of the inlet pressure,the delay time,adjustment time,and rise time of the time parameter of the step response of the damper poppet valve system continuously increase.As the inlet pressure increases,the overshoot of the impulse response of the over-damped poppet valve system increases continuously,and the adjustment time and peak time continuously decrease.The optimal working interval of the experimental valve is between 0.68 MPa and 0.86MPa;as the inlet pressure increases,the overshoot and peak time of the step response of the underdamped poppet valve system continuously increase,and the dynamic response displacement of the poppet valve core is increased.(2)The influence of different spring preload on the dynamic response parameters of poppet valve and the influence of preload on the dynamic response of the valve core are analyzed.The results show that: With the increase of preload,the delay time,adjustment time,and rise time of the dynamic response of the over-damped poppet valve system are continuously decreasing.With the increase of pre-tightening force,the peak time of the under-damped poppet valve system is the overshoots showed a trend of decreasing first and then increasing.Because of the greater preload force on the spool,the dynamic response displacement is decreasing.(3)The variation of the dynamic response parameters of the poppet valve under different spring stiffnesses and the influence of spring stiffness on the dynamic response displacement of the valve core are analyzed.The results show that the poppet valve is under damped.The overshoot of the dynamic response of the vibration system increases with the increase of the spring stiffness,and the peak response time of the dynamic response of the underdamping vibration of the poppet valve decreases with the increase of the spring stiffness.With the increase of the spring stiffness,the valve spool dynamic response curve shows an increasing trend.