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HYDRAULIC DRIVE DEVICE FOR HYDRAULIC WORK 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 4 are arranged a first swinging relief valve 44a, 44b provided with a shockless function to limit a driving pressure or braking pressure of the hydraulic swing motor 40 in order to prevent the pressure from exceeding a first setting pressure, and a second swinging relief valve 46a, 46b 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; in this unit configuration, either one of a mode in which to leave relief characteristics of the first swinging relief valve operative intact, and a mode in which to provide relief characteristics obtained by reducing the first setting pressure of the relief characteristics of the first swinging relief valve to the second setting pressure of the second swinging relief valve is selected by operating a relief pressure change instructing switch 8 and then switching a changeover valve 47a, 47b.
HYDRAULIC DRIVE DEVICE FOR HYDRAULIC WORK 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 4 are arranged a first swinging relief valve 44a, 44b provided with a shockless function to limit a driving pressure or braking pressure of the hydraulic swing motor 40 in order to prevent the pressure from exceeding a first setting pressure, and a second swinging relief valve 46a, 46b 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; in this unit configuration, either one of a mode in which to leave relief characteristics of the first swinging relief valve operative intact, and a mode in which to provide relief characteristics obtained by reducing the first setting pressure of the relief characteristics of the first swinging relief valve to the second setting pressure of the second swinging relief valve is selected by operating a relief pressure change instructing switch 8 and then switching a changeover valve 47a, 47b.
HYDRAULIC DRIVE DEVICE FOR HYDRAULIC WORK MACHINE
HYDRAULISCHE ANTRIEBSVORRICHTUNG FÜR EINE HYDRAULISCHE ARBEITSMASCHINE
DISPOSITIF D'ENTRAÎNEMENT HYDRAULIQUE POUR MACHINE INDUSTRIELLE HYDRAULIQUE
ISHIKAWA KOUJI (author) / KAJITA YUSUKE (author) / SATAKE HIDETOSHI (author) / OOKI TAKATOSHI (author)
2019-06-19
Patent
Electronic Resource
English
HYDRAULIC DRIVE DEVICE FOR ELECTRIC HYDRAULIC WORK MACHINE
| European Patent Office | 2019