HYDRAULIC CIRCUIT DEVICE FOR HYDRAULIC SHOVEL

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic circuit device for a hydraulic shovel, capable of adapting the attachment of a hydraulic breaker a crusher, or the like having various characteristics and capacities, to the hydraulic circuit for the attachment in a simple constitution.

SOLUTION: The hydraulic circuit device for the hydraulic shovel having the hydraulic circuit for the attachment includes: a direction control valve 16 for supplying pressure oil to and discharging it from the attachment connected to the hydraulic circuit for the attachment; a first overload relief valve unit 38 provided on one pipe of the hydraulic circuit for the attachment; a second overload relief valve unit 39 provided on the other pipe of the hydraulic circuit for the attachment; a first proportional solenoid valve 40 for adjusting the relief set pressure of the first overload relief valve unit 38; and a second proportional solenoid valve 41 for adjusting the relief set pressure of the second overload relief valve unit 39.

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