Research On Dynamic And Static Characteristics Of Pilot Large Flow Hydraulic Balance Valve

As one of the key hydraulic components of modern construction machinery,the balance valve plays a vital role in the safety,stability and reliability of hydraulic cranes,excavators and oil pipeline injectors and other important equipment.With the development of the hydraulic system of construction machinery towards high pressure,large flow and high power,the maximum flow of the balance circuit has exceeded1000L/min,and the maximum pressure has exceeded 50 MPa.High pressure and large flow not only bring the balance valve external control regulation difficulties,but also high port flow rate and complex turbulent flow field,more likely to lead to the balance valve cavitation phenomenon,resulting in serious spool vibration and noise.In the process of oil pipeline injector and crane lifting mechanism,the feedback of oil circuit is controlled by the balance valve,and the high order resonance is strengthened,which reduces the safety,stability and reliability of the hydraulic balance circuit,produces energy loss,and shortens the service life of the balance valve and hydraulic engineering machinery.Therefore,this article to a new generation of engineering mechanical balance circuit is used as the background,external pressure servo control research and analyze straight-pilot balancing valve,focus on optimizing the structure parameters of the main valve balancing valves and external control adjusting mechanism of damping characteristics,for the improvement of balance valve and a new generation of high pressure,large flow balancing valve design,provide a reference basis.In view of the influence of the structure of the main valve spool and the parameters of the throttle outlet on the flow field characteristics of the balance valve,this paper starts from the establishment of the calculation model of the main valve U-shaped throttle groove of the balance valve,and takes the Angle of the throttle edge of the main valve as the optimization parameter to study and analyze the influence of the Angle of the U-shaped groove and the oblique U-shaped groove on the flow field characteristics.The results show that increasing the included Angle between U-shaped groove and oblique U-shaped groove is beneficial to improve the flow field characteristics,reduce the energy loss and increase the stability of balance valve.This paper discusses the reason and harm of cavitation in the balance valve,and through the simulation of different Angle models of U groove and oblique U groove,it is found that cavitation occurs at the corner of the valve sleeve.When the cavitation wear is serious,the sealing effect of the balance valve will be weakened.In order to improve the adjustability of the external control regulating mechanism and the stability of the balance valve,a dynamic model of the balance valve based on AMESim is established.The damping characteristics of the balance valve prestage and the external control regulating mechanism are mainly studied.In the dynamic modeling and simulation,the U groove and oblique U groove Angle,damping hole diameter,spring stiffness,disturbance load and other parameters as simulation parameters,study its influence on the dynamic characteristics of the balance valve,get the pilot spool end damping hole R4 and R5 diameter ratio of 1.3～1.647,can ensure the working range of the balance valve,It can also improve the adjustable performance of the external control and regulation mechanism and prevent overload.Finally,this paper summarizes the research results,and points out the research can be improved.