| 摘要 |
The invention relates to a device for the forced oil feed of a hydraulic clamping cylinder (11) which is operated at a defined operating pressure pb and during whose clamping operation a significant oil leakage flow occurs that is returned to the reservoir (32) of a pressure supply system (33). Said pressure supply system is used for the temporary force oil supply of at least one further hydraulic consumer. The pressure supply system comprises a first pump (41) that permanently functions so as to charge a pressure accumulator (52) used as the pressure source for the consumer (11; 61), and a second pump (42) that feeds a cooling circuit in a low power circulation operation mode. A reservoir charging device (41, 42, 59) is used by means of which the reservoir can be charged to a pressure ps when the reservoir pressure falls below a threshold value psu, said pressure ps being significantly higher than the operation pressure pb. The first pump (41) is designed for a pump capacity that supplies the oil leakage flow in the normal operation and that maintains the reservoir pressure at a minimum value ps at which the operating pressure pb is stable. The reservoir charging device comprises a switch valve (5) that switches also the second pump (42) to the reservoir charging operation mode when the reservoir pressure falls below the lower switch threshold value psu. Once the reservoir (52) is charged to a significantly higher switch threshold value pso, the second pump is switched back to the circulation operation mode. |
