HYDRAULIC DRIVE SYSTEM FOR CONSTRUCTION MACHINERY

摘要

In the present invention, a hydraulic drive system for construction machinery is provided with: a first pump having a first rotational shaft and supplying hydraulic oil to a swing motor; a second pump having a second rotational shaft coupled to the first rotational shaft and supplying hydraulic oil to a boom cylinder; an engine having an output shaft coupled to the first rotational shaft or the second rotational shaft; a driven gear mounted onto the first rotational shaft and/or the second rotational shaft, between the first pump and the second pump; a driving gear engaged with the driven gear; a regenerative motor having a third rotational shaft for transmitting power to the driving gear; and a swinging regenerative switching valve for leading hydraulic oil discharged from the swing motor during swinging deceleration to the regenerative motor, and/or a boom regenerative switching valve for leading hydraulic oil discharged from the boom cylinder during boom lowering to the regenerative motor.