HYDRAULIC SYSTEM FOR CONSTRUCTION MACHINE, PROVIDED WITH PROTECTION DEVICE

摘要

Disclosed is a hydraulic system for a construction machine, provided with a protection device, wherein a flow rate discharged from a hydraulic pump is controlled according to oil temperature and a driver can be informed of the information on the oil temperature. According to the present invention, provided is a hydraulic system for a construction machine, provided with a protection device, comprising: a hydraulic actuator operated by using hydraulic oil supplied from a hydraulic pump; a control valve provided to a path between the hydraulic pump and the hydraulic actuator and controlling the flow rate supplied from the hydraulic pump to the hydraulic actuator; an oil cooler provided to a return path from the control valve to a hydraulic oil tank and cooling the hydraulic oil; an oil temperature sensor for detecting the oil temperature of the hydraulic oil tank in real time; a hydraulic pump regulator for controlling the discharge flow rate of the hydraulic pump by adjusting the swivel angle of the swash plate of the hydraulic pump; and a controller for comparing the oil temperature detected by the oil temperature sensor and preset oil temperatures and outputting a control signal to the hydraulic pump regulator so as to restrain the discharge flow rate of the hydraulic pump to a preset flow rate or less, if the detected oil temperature is equal to or lower than a preset low limit value or equal to or higher than a preset high limit value.