CONSTRUCTION MACHINE HAVING HYDRAULIC CIRCUIT

摘要

A construction machine includes a hydraulic actuator circuit including: a first circuit connected to one of travel motors and a boom cylinder; a second circuit connected to the other travel motor and arm cylinder; and a third circuit connected to a slewing motor; control valves for hydraulic actuators; and a merging valve having a first position for unloading hydraulic fluid discharged from a third pump upon no operation except for two travel motors; a second position for merging the hydraulic fluid into the first and second circuits upon a simultaneous operation of the travel motors and an operation of at least one remaining hydraulic actuator except for a boom raising operation; and a third position for merging the hydraulic fluid into the first circuit while blocking it from the second circuit upon the boom raising operation.