| 摘要 |
<p>A press comprising at least one cylinder (10); a main servo motor (40) and a first hydraulic pump (41) which is driven by said main servo motor (40), whose one output is connected through hydraulic lines (43, 44, 54) to said upper chamber (14) and whose other output is connected hydraulically through hydraulic lines (43, 44, 54) to said lower chamber (15); one auxiliary servo motor (50) and a second hydraulic pump (51) which is driven by the auxiliary servo motor (50) and whose one output is connected to the lower chamber (15) through a hydraulic line (53, 55) and to the input of said first hydraulic pump (41) through another hydraulic line (53, 43); and an electronic control unit which adjusts the velocities and directions of the main and auxiliary servo motors (40, 50) according to the requirements in the free fall, pressing and return steps.</p> |
