Hydraulic drive device

Abstract

This hydraulic drive device supplies a working fluid to a hydraulic cylinder including a head-end port and a rod-end port and includes: a hydraulic pump motor including a suction port and a discharge port; an electric motor connected to the hydraulic pump motor; a directional control valve that switches a connection target of the head-end port between the discharge port and the suction port; a regeneration valve that opens and closes a regeneration passage connecting the head-end port and the rod-end port; and an unloader valve that connects, to a tank, a discharge passage connecting the discharge port and the directional control valve.

Dependencies are inferred from the claim text.