| 摘要 |
The hydraulic drive system of a machine press comprises at least two independent hydraulic drive units. In each of said hydraulic drive units at least one hydraulic cylinder, which is connected via valves and a main pressure line under supply pressure to a pump driven by a motor, raises and lowers the upper tool carrier. The rotational speed of the motor is adjustable via the numeric machine control, in which a rotational speed profile defined across the work cycle is stored. Furthermore, a pressure-limiting unit limiting the level of the supply pressure is provided, which at least during a part of the work cycle 1 limits the supply pressure to the lower pressure of a pressure profile defined across the work cycle and stored in the numeric machine control and the actual load pressure increased by an extra amount at the at least one hydraulic cylinder. |
| 主权项 |
1. A machine press (1) comprising a machine framework (3), a lower tool support (4), an upper tool support (7), which can be moved linearly up and down relative to the lower tool support, by means of a hydraulic drive system, by an operating stroke (H), and a numeric machine control (21), wherein the machine press furthermore has the following characteristics:
the hydraulic drive system comprises at least two hydraulic drive units (8, 9) that are independent of one another, wherein each of the hydraulic drive units in turn has the Wowing characteristics:
at least one hydraulic cylinder (12) brings about the linear up and down movement of the upper tool support (7) and is connected, by way of valves (22, 26, 27) and a main pressure line (20) that stands under a supply pressure, with a pump (16) driven by a motor (17), which pump draws hydraulic fluid from a tank (18);the speed of rotation of the motor (17) is adjustable by way of the numeric machine control (21), wherein a speed-of-rotation profile defined over the work cycle is stored in the memory of the numeric machine control;a pressure-limiting unit limits the level of the supply pressure at least during a part of the work cycle, to the lower pressure of a pressure stored in the memory of the numeric machine control (21), defined over the work cycle, and the actual load pressure at the at least one hydraulic cylinder (12), increased by a margin. |
