HYDRAULIC CONTROL DEVICE OF OPERATING MACHINE

摘要

A hydraulic pump (2) driven by an engine, a hydraulic actuator (3), and a negative control circuit (4) are provided on an open center hydraulic circuit (10), for guiding the hydraulic pressure in the center bypass to the hydraulic pump (2), as a negative control pressure. A negative control pressure control device (6) that controls the negative control pressure to an arbitrary value is also provided on the negative control circuit (4). The pump characteristic of the hydraulic pump (2) is set such that the discharge flow rate is minimized when the negative control pressure in the negative control circuit (4) is equal to or greater than a first predetermined pressure. Furthermore, an idling detection device (5) that detects whether the hydraulic actuator (3) is in a non-operated state or not is provided. The negative control pressure is forcefully controlled to the first predetermined pressure or higher when the non-operating state is detected.