HYDRAULIC SYSTEM FOR CONSTRUCTION MACHINERY

摘要

Disclosed is a hydraulic system wherein a driver first selects or disengages a function when performing, by way of example, an excavation operation or suspend operation using an excavator. The hydraulic system according to the present invention is a hydraulic system for construction machinery, the system comprising: a first and a second hydraulic pump connected to an engine; a first and a second hydraulic actuator respectively connected to the first and second hydraulic pumps; a main control valve provided with spools which are respectively provided on a flow pathway between the first and second hydraulic pumps and the first and second hydraulic actuators and which respectively control start-up, suspension and direction switching of the first and second actuators during changeover; a first and a second actuating lever which respectively output actuation signals proportional to the extent of actuation by a user; a control device for limiting the amount of flow applied to a spool on either the first-hydraulic-actuator or the second-hydraulic-actuator side sharing the first hydraulic pump or second hydraulic pump in accordance with the actuation of the first actuating lever or the second actuating lever by the user for the purpose of a clockwise turning function; and a control unit for controlling the drive of the control device in such a way as to allow switching to the clockwise-turning function or disengagement from the clockwise-turning function due to a user decision.