Patent ID: 8579595

Claim:
A cooling device for a construction machine, comprising: two or more hydraulic motors that rotate positively and reversibly to correspond to a supplying direction of pressure oil and drives rotatably cooling fans connected thereto, respectively; a switching valve switching rotation directions of the two or more hydraulic motors and by switching the supplying direction of the pressure oil supplied to the two or more hydraulic motors from a hydraulic pump; and two or more flow rate makeup valves controlling an additional flow supplied upstream of the two or more hydraulic motors when a pressure drop is generated upstream of the two or more hydraulic motors on the basis of the supplying direction of the pressure oil; wherein the flow rate makeup valves make up the flow to each pressure drop region of the two or more hydraulic motors; wherein the two or more flow rate makeup valves receive the flow from an oil tank; at least one of the two or more flow rate makeup valves is installed on a hydraulic line L 4 connecting a hydraulic line L 1 , which connects the switching valve with the hydraulic pump, with the oil tank; and at least the other of the two or more flow rate makeup valves is installed on a hydraulic line L 5 connecting the two or more hydraulic motors with the oil tank.