HYDRAULIC DRIVE DEVICE OF ELECTRIC HYDRAULIC MACHINERY

摘要

In addition to performing load-sensing control of a main pump (2) by rotational frequency control of an electric motor (1) using a controller (50), cutoff control for controlling the rotational frequency of the main pump (2) is performed so as to reduce the discharge flow rate of the main pump (2) when the discharge pressure of the main pump (2) rises above a first specified pressure (Ppso) near the set pressure (Pmax) of a main relief valve (14). As a result, in the electric hydraulic machinery, which drives the hydraulic pump using the electric motor to drive an actuator and performs load-sensing control by rotational frequency control of the electric motor, wasted power consumption by the operation of the relief value is limited, sudden elevations in electric motor rotational frequency are limited, and higher efficiency and comfort can be secured.