ELECTRO-HYDRAULIC DRIVE SYSTEM FOR A WORK MACHINE

摘要

An electro-hydraulic drive system for a work machine which drives an upper rotary body (16) by controlling a flow rate of a hydraulic fluid by a control valve (6), comprises an electro-hydraulic pump (3) including a hydraulic pump (4) driven by an engine (2), and a first electric motor (5), and an electro-hydraulic motor (9) including a hydraulic motor (10) rotated by the hydraulic oil supplied from the electro-hydraulic pump (3), and a second electric motor (11), and a controller (7) which determines an operating state of the first electric motor (5) and an operating state of the second electric motor (11) based on a load of the electro-hydraulic pump (3) and a load of the electro-hydraulic motor (11), and is able to perform an efficient operation by using a hydraulic pressure (fluid pressure) and electric power