公开(公告)号：US20220186459A1

公开(公告)日：2022-06-16

申请号：US17437484

申请日：2020-06-18

Applicant: HITACHI CONSTRUCTION MACHINERY CO., LTD.

Inventor： Teruki IGARASHI ,  Akihiro NARAZAKI ,  Masamichi ITOU

IPC: E02F3/43 ,  E02F3/42 ,  E02F9/22 ,  E02F9/26

Abstract: A hydraulic actuator includes a control valve unit that controls a flow of a hydraulic fluid supplied from a hydraulic pump to a plurality of hydraulic actuators, a plurality of control lever devices that output a pilot pressure actuating the control valve unit, with use of a discharged pressure from a pilot pump as a source pressure, a solenoid valve unit including a plurality of solenoid pressure reducing valves connected between the plurality of control lever devices and the control valve unit, and a controller configured to calculate velocity limits for the plurality of hydraulic actuators on the basis of signals from a plurality of posture sensors and control openings of the solenoid pressure reducing valves, in which the controller is configured to control the openings of the solenoid pressure reducing valves for arm crowding and arm dumping to be larger than an opening based on the velocity limits while a boom raising operation signal is being output from the control lever devices.

公开(公告)号：US20210230843A1

公开(公告)日：2021-07-29

申请号：US15734593

申请日：2019-03-27

Applicant: HITACHI CONSTRUCTION MACHINERY CO., LTD.

Inventor： Hiroki TAKEUCHI ,  Shiho IZUMI ,  Ryu NARIKAWA ,  Shuuichi MEGURIYA ,  Teruki IGARASHI

IPC: E02F9/26 ,  E02F9/22 ,  E02F9/20 ,  E02F3/32 ,  E02F3/43 ,  F15B15/14

Abstract: An articulated-type front work implement has a boom, an arm, and a bucket that are driven members coupled to each other; a boom cylinder, an arm cylinder and a bucket cylinder that are hydraulic actuators each of which drives a corresponding one of the plurality of driven members on the basis of an operation signal; a plurality of operation members each outputting the operation signal to one of the hydraulic actuators; and a controller that outputs the operation signal to at least one of the plurality of hydraulic actuators or executes area limiting control of correcting the output operation signal such that the front work implement moves on a target surface preset for a work target of the front work implement or within an area above the target surface, and corrects the operation signal on the basis of information related to operation of the hydraulic actuator.

公开(公告)号：US20200181883A1

公开(公告)日：2020-06-11

申请号：US16639793

申请日：2018-10-30

Applicant: HITACHI CONSTRUCTION MACHINERY CO., LTD.

Inventor： Teruki IGARASHI ,  Shiho IZUMI ,  Ryu NARIKAWA ,  Shuuichi MEGURIYA ,  Hiroki TAKEUCHI

IPC: E02F9/26 ,  E02F3/32 ,  E02F9/20 ,  E02F9/22 ,  E02F3/43

Abstract: A controller outputs a first velocity (first limiting velocity) as a limiting velocity for a boom cylinder when a boom lowering operation amount is smaller than a first operation amount, and outputs a second velocity when the boom lowering operation amount is equal to or larger than the first operation amount. The first velocity is set to decrease according to a decrease in a target surface distance. The second velocity is defined by a weighted average of the first velocity and a third velocity (second limiting velocity) set to change according to one of the target surface distance and the boom lowering operation amount of the operation device, and is set such that an increase in the boom lowering operation amount reduces a weight for the first velocity while increasing a weight for the third velocity.