Hydraulic drive for sheet metal forming press - has first hydrostatic machine to regulate pressure and second hydrostatic machine to expel pressure medium from hydraulic cylinder

摘要

The first hydrostatic machine (30) is an axial piston assembly and alternately works on both sides for regulating pressure. During the return stroke of the holder (17), the pressure medium flows out of the hydraulic cylinder (21) through a second hydrostatic machine (70). The second hydrostatic machine is driven as a hydro motor during the return stroke and expels the pressure medium from the hydraulic cylinder. The first hydrostatic machine is provided with load dependent control which controls the pressure regulation. ADVANTAGE - Power is saved by using the pressure of the pressure medium flowing from the cylinder.