| 摘要 |
PROBLEM TO BE SOLVED: To reduce engine lug down generated at the time of charging high load and to quickly return engine speed to a rated value, without causing deterioration of energy efficiency and lowering of an operation response, in the engine load control device of a hydraulic working machine. SOLUTION: This device is provided with a rotation sensor 30, a throttle position sensor 31, temperature sensors 32, 33, a controller 34 and unload valves 35, 36. When an operating lever 10a for boom is operated and engine speed lowering the amount for prescribed time becomes a prescribed value A or more, a throttle position Y is in the vicinity of 100%. When each of an engine cooling water temperature Tw and a hydraulic fluid temperature is lower than each allowable limit temperature, both the unload valves 35, 36 are turned on, and the unload valves 35, 36 are kept at 'ON' states until the supply of pressure oil to hydraulic motors 22, 23 is stopped, auxiliary pumps 5, 6 are made in no-load states and engine speed Nr is returned to engine speed higher than a prescribed engine speed.
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