Dynamic Simulation Of Cartridge Counterbalance Vavle Used In Roadheader

Balance circuit is a common control circuit of hydraulic drive and widely used in engineering machinery, construction machinery, metallurgical machinery and other industries.The counterbalance valve is a key component of balance circuit,the counterbalance valve studied by this-paper is used in roadheader,when the cutting of roadheader moves,the crawling、jitter is always appearing in hydraulic cylinder,and the counterbalance valve is easy to produce cavitation、 whirlpool and noise.By the countbalance valve motion analysis,simulation analysis on the hydraulic system through AMESim,and flow field analysis through Fluent,to analyze the crawling、jitter phenomena and put forward the suggestion to reduce cavitation、whirlpool and noise.This paper first analyzes the working principle and working conditions of the counterbalance valve used in roadheader,and then has stress analysis of cutting,and gets the load variation of the hydraulic cylinder.At last,has stress analysis of the counterbalance valve spool and establishes the kinematic equations,at the same time,builds flow equation and flow continuity equation of the valve port,and analyzes the dynamic characteristics of the counterbalance valve.Build the hydraulic control system of the cutting of EBZ120roadheader in AMESim,and parameterize the simulation model based on the working conditions.Through simulation analysis, the pressure of the hydraulic cylinder chamber without rod reaches a steady state,5.1MPa, the flow rate is26.9L/min, and the pressure of the hydraulic cylinder chamber with rod stability of the rod reaches a steady state,2.58MPa, the flow rate is14L/min.The speed of the hydraulic cylinder piston reaches a steady state0.022m/s.With the effect of pilot oil pressure and inlet pressure,finally the displacement of the check valve spool is0.6mm, and the displacement of the main valve spool is2mm,and the opening of the counterbalance valve is1.4mm.By changing the size of the control oil ports, the load of hydraulic cylinder, the preload of regulator spring,the regulator spring’s modulus of elasticity and other important parameters,and through the batch operation simulation,study the impacts of each parameter on the counterbalance valve,in order to optimize the counterbalance valve and give some advice.And then,study the impacts of seals friction force on the counterbalance valve,and apply a calculate way that how to figure out the friction force of PTFE seals,and build a new simulation model,through simulation,get the fact that the reason why the counterbalance valve and the hydraulic cylinder piston crawls is that seals friction force is too large,and explain the details of crawls clearly.Build two kinds of models in FLUENT for the check valve and the main valve,the same opening and the different cone angle,the same cone angle and the different opening. Studied the effect of the opening and the cone angle on the low pressure area,the incident angle,the maximum speed of oil and the maximum speed area, the whirlpool area,the impact on valve core and valve seat.At last,put forward the optimization scheme of counterbalance valve.This paper provides a reference approach for the optimization of the counterbalance valve’s design and eliminating the crawling phenomenon of the hydraulic cylinder,at the same time, provides a reference for the study of the hydraulic components.