Designing of dynamic calculation model of press with pump-accumulator drive working stroke

Peculiarities of hydraulic press ram moving on different stages of the working stroke on the basis of experimental oscillogram are considered. Rated scheme of the working stroke with pointing out the assumptions of the “hard” hydraulic drive model is adduced. Dynamic calculation models of the first and second stages of the working stroke of hydraulic press with pump-accumulator drive are designed. Description of the coefficients of differential Ricatti equation is given, its analytical decision concerning real forging press is adduced. Presented moving metal-and-fluid masses, viscous hydraulic resistance of the line “accumulator – press” and the active press force on the working stroke are considered in detail. Its influence on ram moving on the working stroke is revealed. The influence of constructive characteristic and shutting time of the control valve on the dynamics of ram decelerating on the working stroke is analyzed.