HYDRAULIC DRIVE DEVICE OF POWER-OPERATED HYDRAULIC OPERATION MACHINE

When used for an electrically-operated hydraulic work machine that drives an actuator with a hydraulic pump driven by an electric motor and exercises load sensing control by controlling the rotation speed of the electric motor, the present invention increases the useful life of an electrical storage device, which is an electrical power source for the electric motor, by suppressing the horsepower consumption of the hydraulic pump, prolongs the operating time of the electrically-operated hydraulic work machine, and reduces the size of the electric motor. The present invention uses a controller 50 to exercise load sensing control over a variable displacement main pump 2 by controlling the rotation speed of the electric motor 1, and provides the main pump 2 with a torque control device 17 that reduces the delivery rate of the main pump 2 when the delivery pressure of the main pump 2 increases, or provides the controller 50 with a control algorithm that performs the same function as the torque control device 17.