HYDRAULIC CIRCUIT APPARATUS FOR HYDRAULIC SHOVEL

摘要

A hydraulic circuit apparatus for a hydraulic shovel having a hydraulic circuit for an attachment is provided with a direction control valve (16), which provides and removes hydraulic fluid to an attachment which connects to the hydraulic circuit for an attachment; a first overload relief valve unit (38), provided on one set of piping in the hydraulic circuit for an attachment; a second overload relief valve unit (39) provided on the other set of piping in the hydraulic circuit for an attachment; a first proportional solenoid valve (40), which adjusts the relief pressure setpoint of the aforementioned first overload relief valve unit (38); and a second proportional solenoid valve (41), which adjusts the relief pressure setpoint of the second proportional relief valve unit (39). As a result, it is possible for hydraulic breakers, crushers, or the like with various characteristics and capacities to be accommodated by the hydraulic circuit for an attachment by means of a simple configuration.