公开(公告)号：EP4039892A1

公开(公告)日：2022-08-10

申请号：EP20871610.0

申请日：2020-09-29

Applicant: Hitachi Construction Machinery Co., Ltd.

Inventor： AKITA, Tarou ,  KOBAYASHI, Takahiro ,  NARAZAKI, Akihiro ,  ITO, Masamichi

IPC: E02F9/22

Abstract: When an operation amount of an operation lever 1a or 1b corresponding to a boom cylinder 5 is equal to or smaller than an operation amount of an operation lever 1a or 1b corresponding to an arm cylinder 6, an estimated velocity of the arm cylinder used for region limiting control is computed on the basis of a first condition defining, in advance, a relation between the operation amount of the operation lever 1a or 1b and the estimated velocity of the arm cylinder 6. When the operation amount of the operation lever 1a or 1b corresponding to the boom cylinder 5 is larger than the operation amount of the operation lever 1a or 1b corresponding to the arm cylinder 6, the estimated velocity of the arm cylinder 6 used for the region limiting control is computed as a velocity higher than the estimated velocity of the arm cylinder 6 computed on the basis of the first condition. The behavior of a work device can thereby be stabilized.

公开(公告)号：EP4191073A1

公开(公告)日：2023-06-07

申请号：EP21910026.0

申请日：2021-11-11

Applicant: Hitachi Construction Machinery Co., Ltd.

Inventor： AKITA, Tarou ,  SHIRAKAWA, Yoshihiro ,  OGURA, Kohei ,  KANEHAMA, Mitsuhiko

IPC: F15B11/00 ,  E02F9/22 ,  F15B11/08 ,  F15B11/16 ,  F15B21/0427

Abstract: A work machine includes a flow control valve that controls a flow rate of a hydraulic fluid supplied to a hydraulic actuator, a center bypass line that introduces the hydraulic fluid from a pump through a center bypass passage section of the flow control valve into the tank, a bypass cutoff valve that controls an opening of the center bypass line, a solenoid proportional valve that generates a pilot pressure for controlling the bypass cutoff valve, a pilot valve that generates a pilot pressure for controlling the flow control valve on the basis of an amount of operation of an operation device, and a controller that controls the solenoid proportional valve on the basis of the amount of operation. The controller controls the solenoid proportional valve to reduce an opening area of the bypass cutoff valve according to an increase in the amount of operation in a case the amount of operation is less than a predetermined amount of operation, and controls the solenoid proportional valve to make the opening area of the bypass cutoff valve larger than the minimum opening area in a case the amount of operation is a maximum amount of operation.

公开(公告)号：EP3483348A1

公开(公告)日：2019-05-15

申请号：EP17823797.0

申请日：2017-02-28

Applicant: Hitachi Construction Machinery Co., Ltd

Inventor： IZUMI, Shiho ,  MEGURIYA, Shuuichi ,  NARIKAWA, Ryuu ,  ISHIKAWA, Kouji ,  AKITA, Tarou

IPC: E02F9/20 ,  E02F3/43 ,  F02D29/02 ,  F02D29/04

Abstract: A work machine (1) having a controller (40) that can perform area limiting control, the work machine further includes a machine control ON/OFF switch (17) that alternatively selects an ON position permitting execution of the area limiting control and an OFF position prohibiting execution of the area limiting control. The controller (40) has an engine control section (63) that performs automatic idling control when a predetermined period of time (T1) has elapsed after a point in time when all of operation levers (1, 23) have attained a neutral state. The engine control section (63) is configured to execute the automatic idling control during when the switch (17) is in the OFF position and not to execute the automatic idling control during when the switch (17) is in the ON position.

公开(公告)号：EP3483346A1

公开(公告)日：2019-05-15

申请号：EP17823798.8

申请日：2017-02-28

Applicant: Hitachi Construction Machinery Co., Ltd.

Inventor： IZUMI, Shiho ,  NARIKAWA, Ryuu ,  MEGURIYA, Shuuichi ,  AKITA, Tarou ,  ISHIKAWA, Kouji

IPC: E02F3/43 ,  F15B11/024 ,  F15B11/05 ,  F15B11/08

Abstract: Provided is a work machine in which fluctuation in the speed of the hydraulic actuator due to hydraulic fluid regeneration during the execution of machine control is suppressed, thereby making it possible to improve work efficiency while securing the control accuracy of the machine control. A controller 100 has an area limiting control section 110 correcting the pilot pressures of pilot lines 41 through 43, a regeneration control section 120 adjusting the flow rate of the hydraulic fluid caused to flow from a tank side line 28a of an arm cylinder 12 into a pump side line 28b thereof between zero and a predetermined upper limit value, and a regeneration control switching section 130 that issues an order to the regeneration control section 120 to set the predetermined upper limit value to a first set value F1 when the function of the area limiting control section is invalid and that issues an order to the regeneration control section 120 to set the predetermined upper limit value to a second set value F2 that is smaller than the first set value when the function of the area limiting control section is effective.