| 摘要 |
The force required to deform a workpiece in hydraulic presses is applied by the piston of a dual action hydraulic cylinder. Initially, the force of pressure falls during the transition from quick movement to the speed of compression as a result of compression of the pressure medium while the pressure builds up. In order to reduce the drop in the force of pressure, the pressure medium is evacuated from a first cylinder chamber (3.1, 4.1) assigned to the direction in which the press is opened over a first distance and fed to a second cylinder chamber (3.2, 4.2) assigned to the direction in which the press is closed. Pressure is maintained in the cylinder chambers in such a way that the forces acting upon the piston surfaces of the cylinder cancel each other out. The first cylinder chamber (3.1, 4.1) is discharged before deformation of the workpiece begins. The pressure that prevails in the second cylinder chamber (3.2, 4.2) exerts a force upon the workpiece, resulting in the deformation thereof. |
