METHOD AND DEVICE FOR CONTROLLING THE SYNCHRONIZATION OF CYLINDER/PISTON UNITS AND FOR REDUCING PRESSURE PEAKS DURING FORMING AND/OR FINEBLANKING ON A FINEBLANKING OR STAMPING PRESS

摘要

The invention relates to a method and a device for controlling thesynchronization of cylinder/piston units for counterforce ramsand/or vee rings and for reducing pressure peaks during thefineblanking and/or forming of workpieces on a fineblanking orstamping press equipped with at least one tool.The basic object of the invention is to provide a method and adevice for controlling the synchronization of cylinder/piston unitsand at least one main ram and for reducing pressure peaks duringforming and/or fineblanking on fineblanking or stamping presses,which discharges any recoil caused by the impact between the punchand the workpiece, independently of quantity, from the controllingof the working pressure of the hydraulic fluid, bringing about amarked improvement in the synchronization properties of thecylinder/piston units and the main ram through a constant pressurecharacteristic in the hydraulic system including with high cycletimes and speeds.This object is achieved in that first of all the cylinder/pistonunits are continuously maintained at a preadjustable cushionpressure (P1) and that the cylinder/piston units are then subjectedto a preadjustable displacement pressure (P2) from a connectablehigh-pressure source, with said pressure being set to a pressure(PU) varying between the cushion pressure (P1) and the pressure forforming and/or blanking by supplying a separate control oilquantity to a second accumulator via a central control unit,whereby a rise in pressure caused by the impact between the tooland the workpiece is regulated, independently of quantity, from thepressure (P3) in the second accumulator to a permissible setpressure by discharging a significant part of the pressure pulseinto a separate tank, and that the available cushion pressureallows ejection of the workpiece to be synchronized with retractionof the press ram.