Hydraulic circuit device for hydraulic operated working machine e.g. crane, has valve arrangement provided in hydraulic passage, where part of hydraulic fluid return is exhausted into tank over discharge valve arranged in hydraulic passage

摘要

The device has a hydromotor (8) for optional lifting or lowering a load. A flow control valve arrangement is provided in a hydraulic passage (16). The flow control valve arrangement is formed to feed a part of hydraulic fluid return again as a hydraulic fluid inlet into another hydraulic passage (14) after reaching a maximum load pressure, which is higher than inlet pressure in the latter hydraulic passage. A part of the hydraulic fluid return is exhausted into a tank over a discharge valve (4) arranged in the former hydraulic passage.