Evaluation of the Effective Variables on the Performance of the Hydraulic Pilot Valve Including the Orifice with the Fixed and Moving Parallel Surfaces

Considering the widespread use of hydraulic pilot valves, including orifices with fixed and moving parallel surfaces in the structure of two-stage pressure control valves, it is necessary to evaluate and analyze their performance in order to optimize and control. In this article, the effect of slope, length and curvature of the valve seat on pressure distribution and oil flow rate passing through the pilot valve chamber, flow coefficient, force coefficient and force on the moving part of the valve were investigated using numerical and experimental methods. In all working conditions, the difference between the results obtained from the experimental measurements of the flow coefficient and the force on the moving part of the pilot valve with the numerical results was determined to be less than 6%. Investigation results showed that reducing the slope and length of the seat, the force on the moving part of the valve is increased. Meanwhile, creating a curve in the inlet port of the valve causes 36% reduction in the force on the moving part of the valve and 70% increase in its flow coefficient. The force on the moving component of the valves including orifices with fixed and moving parallel surfaces was determined to be 20% lower on average than the valve with a vertical seat.