公开(公告)号：EP4435271A1

公开(公告)日：2024-09-25

申请号：EP23759688.7

申请日：2023-02-07

申请人： Hitachi Construction Machinery Co., Ltd.

发明人： KOWATARI Yoichi ,  KOFUNA Shuuhei ,  HAYASHI Tomoaki

IPC分类号： F15B11/08 ,  E02F9/22 ,  F15B21/047

CPC分类号： F15B21/047 ,  F15B11/08 ,  E02F9/22

摘要： A work machine includes: a hydraulic actuator; a closed-circuit pump that is connected to the hydraulic actuator in a closed circuit, and supplies and discharges a hydraulic working fluid to and from the hydraulic actuator; an open-circuit pump that is connected to the hydraulic actuator in an open circuit, and supplies the hydraulic working fluid to the hydraulic actuator; a charge pump; a charge flow path that introduces the hydraulic working fluid delivered from the charge pump to the closed circuit; an excess fluid discharging device that discharges an excess hydraulic working fluid of the closed circuit to the charge flow path; and a controller that controls a delivery capacity of the closed-circuit pump and a delivery capacity of the open-circuit pump. The controller increases the delivery capacity of the open-circuit pump, or reduces the delivery capacity of the closed-circuit pump when a state of a pressure of the charge flow path has transited to be lower than a predetermined pressure threshold from equal to or higher than the predetermined pressure threshold, or when a state of the work device has transited to a state of performing the excavation work from a state of not-performing the excavation work.