| 主权项 |
1. A press (1) comprising:
a press frame (2) including a press table (3), a plunger (7) which is supported in the press frame (2), the plunger (7) having a cycle so as to be movable back and forth between a pair of upper dead center positions (To) and a lower plunger dead center position (Tu), a servo drive (14) including at least one servomotor (15, 16) for driving the plunger (7) and means for utilizing an elastic deformation of the press (1) to provide a substantial mechanical deformation energy to aid or replace the at least one servomotor (15, 16) for obtaining a load relief for the at least one servomotor (15, 16) in braking the plunger (7) after plunger has past the lower plunger dead center position (Tu), wherein the means for utilizing an elastic deformation of the press (1) to provide a substantial mechanical deformation energy to aid or replace the servo drive (14) for obtaining a load relief for the at least one servomotor (15, 16) after plunger has past the lower plunger dead center position (Tu) comprises a control arrangement (21) in operative controlling relationship with the servo drive (14), the control arrangement (21) for controlling the servo drive (14) to control the movement of the plunger (7) as follows:
in a first operating mode in accordance with a predetermined guide angle/position-curve (27) based on a guide angle (α) during a first part of the plunger cycle between a first upper dead position (To) and the bottom dead center (Tu) using a position control for controlling and permitting a first deviation of the plunger (7) above the predetermined guide angle/position-curve (27) defining a first position tolerance (Tol 1) substantially accurately following the predetermined guide/angle position-curve (27),and then for operating the press plunger (7) by controlling the movement of the plunger (7) in a second part of the plunger cycle immediately past bottom dead center position (Tu) by switching to a second operating mode using a position control or a force control for permitting a second deviation of the plunger (7) from the predetermined guide/angle position curve (27) defining a second position tolerance (Tol 2) for a predetermined guide angle range (B) or which second position tolerance (Tol 2) may be fully omitted and wherein the plunger (7) may be disposed at a substantially greater distance from the press table (3) then in the first operating mode, and,
and then for operating the press plunger (7) by controlling the movement of the plunger (7) in the second part of the plunger cycle past the predetermined guide angle range (B) by switching back to the first operating mode. |
