Digital Variable Axial Piston Pumps

Description: Axial piston pumps come with digital P/Q controls greatly improving the potential resources. The photo shows a variable piston pump equipped with advanced digital controller for the closed-loop control of the swash plate position and thus of system's P/Q (pressure/flow) regulation. Digital P/Q controller integrates the combined regulation of pressure and flow with max power limitation. A remote pressure transducer on the system interfaces to the pump digital driver. If the real value of pressure (measured by the transducer) remains below the relevant reference signal by the machine's controller, then the digital driver regulates the swash plate position in closed-loop according to the flow reference signal. When the real pressure approaches closer to the reference signal, the driver automatically performs the closed-loop control of pressure with accurate high dynamic pressure profiles. The digital control ensures high performances, better flow and pressure linearity, better flow knee, and internal leakage compensation (controlled flow independent from the load variations). The pictured version is equipped with sequence module to grant a minimum piloting pressure (18 bar) when the actual pressure falls below that value (in absence of a pressure transducer). Variable displacement piston pumps with digital closed-loop controls are widely used in plastic injection presses. The system benefits can be summarized as high dynamic response, optimisation of application performances through software setting of parameters, real time selection of different P/Q parameters set, energy saving and power limitation function and system simplification through the reduction of proportional controls. Similar P/Q digital options may be integrated in Atos proportional valves, proportional cartridges and in new electrohydraulic servo actuators.