Mattingly & Malur, PC
Hydraulic drive system for hydraulic working machine
A hydraulic drive system designed so that while maintaining intact a structure of a relief valve having a shockless function, the drive unit hydraulic drive system facilitates changing a driving pressure or braking pressure of a hydraulic swing motor and hence, changing a maximum driving torque or braking torque of the hydraulic swing motor. Inside a swing motor unit is arranged a first swinging relief valve provided with a shockless function to limit a driving pressure or braking pressure of the hydraulic swing motor in order to prevent the pressure from exceeding a first setting pressure. Also, a second swinging relief valve is provided for limiting the driving pressure or braking pressure of the hydraulic swing motor in order to prevent the pressure from exceeding a second setting pressure that is lower than the first setting pressure.
HITACHI CONSTRUCTION MACHINERY CO., LTD.
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F15B E02F E02F F15B E02F F16H F16H E02F F15B F15B E02F F15B F16H E02F
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Takatoshi Yusuke Hidetoshi Kouji
Ooki Kajita Satake Ishikawa