| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic system of a hydraulic excavator capable of preventing swing and unintended operation of turn due to erroneous operation while a machine body is lifted by using a jack to reduce operator's fatigue. SOLUTION: In this hydraulic system of the hydraulic excavator, a first sensor 61 and a second sensor 62 of an erroneous operation prevention system 60 detect load pressure on a rod side of a boom cylinder 31 and on a bottom side of a blade cylinder 32, and a controller 63 determines whether the hydraulic excavator is lifted by the jack or not and outputs a control signal to a solenoid 72 of a communication selector valve 71 while it is lifted by the jack to switch the communication selector valve 71 to a shut-off position. Consequently, transmission of pilot pressure from pilot pumps 28 to remote-controlled valves 53a, 53b, 54a, 54b is shut off, and direction selector valves 43, 44 for swing and turn are held at a neutral position. COPYRIGHT: (C)2009,JPO&INPIT
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