Patents by Inventor Kouji Ishikawa

Kouji Ishikawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20190169818
    Abstract: A hydraulic excavator includes a controller (40) that executes region limiting control to forcibly raise a boom (8) in such a manner that a position of a tip end of a bucket (10) is kept on a target excavation surface and within a region above the target excavation surface if an operation device (45b, 46a) issues an action direction to an arm (9) or the bucket. The controller determines which is selected as a control mode over a raising speed of the boom at a time of executing region limiting control, a first mode or a second mode specified by a raising speed lower than a raising speed of the first mode if the tip end of the bucket is located below the target excavation surface, and controls the raising speed of the boom based on a result of determination.
    Type: Application
    Filed: April 5, 2017
    Publication date: June 6, 2019
    Inventors: Ryu NARIKAWA, Manabu EDAMURA, Kouji ISHIKAWA, Shiho IZUMI
  • Patent number: 10309079
    Abstract: An object of the present invention is to provide a hydraulic control system for a work machine that is capable of reducing the loss caused by flow division while reducing a decrease in the speed of a hydraulic actuator due to a combined operation. The hydraulic control system for a work machine includes a first hydraulic actuator, one hydraulic pump, a second hydraulic actuator, and another hydraulic pump. The hydraulic control system further includes operating instruction detection means and pump flow control means. The operating instruction detection means detects that operating instructions are issued to the first hydraulic actuator and the second hydraulic actuator. The pump flow control means individually adjusts the delivery flow rate of the one hydraulic pump and the another hydraulic pump in accordance with operation amounts designated by the operating instructions for the first and second hydraulic actuators.
    Type: Grant
    Filed: April 14, 2015
    Date of Patent: June 4, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hidekazu Moriki, Shinya Imura, Kouji Ishikawa, Ryohei Yamashita
  • Patent number: 10301793
    Abstract: When hydraulic fluid discharged from a hydraulic actuator is to be recovered for driving a different hydraulic actuator, the recovery frequency is increased to achieve further energy saving. To this end, a pressure increasing circuit 36 is provided in which a communication pressure increasing valve 12 is disposed in a communication passage 26 that connects a bottom side line 23 of and a rod side line 24 a boom cylinder 4. A recovery control valve 11 is controlled such that, when a first operation unit 5 is operated in a boom lowering direction (own weight falling direction of the boom) and a second operation unit 6 is operated simultaneously, only if the pressure at the bottom side of the boom cylinder 4 is higher than the pressure at the arm cylinder side that is a recovery destination of hydraulic fluid, the recovery control valve 11 is opened to recover the flow rate discharged from the bottom side of the boom cylinder 4 to the arm cylinder side.
    Type: Grant
    Filed: October 2, 2014
    Date of Patent: May 28, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Takatoshi Ooki, Shinya Imura
  • Patent number: 10302028
    Abstract: Provided are a work machine, a power unit, and a diesel engine of a work machine that make it possible to reduce emitted noxious substances to levels below reference values stipulated by exhaust gas regulations in advanced countries and regions while also omitting or simplifying a post-treatment device. A hydraulic pump is driven by a diesel engine that limits maximum output torque in a low revolution speed region lower than a high revolution speed region including a rated revolution speed in such a manner that the maximum output torque has a characteristic of intermediate torque lower than torque of a maximum output horsepower point at the rated revolution speed, and a hydraulic actuator is driven by hydraulic fluid delivered from the hydraulic pump.
    Type: Grant
    Filed: February 10, 2015
    Date of Patent: May 28, 2019
    Assignees: Hitachi Construction Machinery Co., Ltd., Kabushiki Kaisha Toyota Jidoshokki
    Inventors: Manabu Edamura, Yuusuke Kajita, Masatoshi Hoshino, Kouji Ishikawa, Kentarou Itoga, Naoki Ishikawa, Tsutomu Umehara
  • Patent number: 10280594
    Abstract: A hydraulic fluid energy regeneration system for a work machine capable of securely maintaining a brake pressure even when a solenoid valve or the like is erroneously rendered open by an electrical failure is provided.
    Type: Grant
    Filed: February 23, 2016
    Date of Patent: May 7, 2019
    Assignee: HITACHI CONSTRUCTION MACHINERY CO., LTD.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Shinya Imura
  • Patent number: 10280593
    Abstract: Provided is a hydraulic fluid energy regeneration device for a work machine, including: a regeneration hydraulic motor driven by discharged return hydraulic fluid; a first hydraulic pump mechanically connected to the regeneration hydraulic motor; a second hydraulic pump that delivers an hydraulic fluid for driving a first hydraulic actuator and/or a second hydraulic actuator; a junction line that allows the hydraulic fluid delivered by the second hydraulic pump to be joined; a second regulator that regulates the delivery flow rate of the second hydraulic pump; and a first regulator that regulates the flow rate of the hydraulic fluid coming from the first hydraulic pump and flowing through the junction line.
    Type: Grant
    Filed: May 16, 2014
    Date of Patent: May 7, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Takatoshi Ooki, Shinya Imura
  • Publication number: 20190127946
    Abstract: A work machine includes: a multi-joint type work implement; a plurality of hydraulic actuators driving the work implement; an operation device outputting an operation signal to the plurality of hydraulic actuators; a storage section storing a target configuration defined by connecting a plurality of target surfaces; a control object surface selection section that in the case where a control point set at a claw tip of a bucket is under the target configuration, uses a target surface closest to the control point on the target configuration as a control object surface; and a target operation control section that controls the plurality of hydraulic actuators such that the operational range of the control point is limited to the control object surface and a region above the same in the case where an excavation operation is input from an operator via the operation device.
    Type: Application
    Filed: February 28, 2017
    Publication date: May 2, 2019
    Inventors: Daito SAKAI, Shiho IZUMI, Ryuu NARIKAWA, Kouji ISHIKAWA
  • Patent number: 10273658
    Abstract: The construction machine includes: a control valve that switchingly supplies hydraulic fluid from a hydraulic pump to a hydraulic actuator; a control valve drive device that supplies pilot secondary hydraulic fluid to the control valve in accordance with an operation of an operation lever device; a pilot hydraulic pump that supplies pilot primary hydraulic fluid to the control valve drive device; a pressure accumulation device that recovers return hydraulic fluid returned from the hydraulic actuator. The construction machine further includes: a check valve provided in a line between the pilot hydraulic pump and the control valve drive device; a pressure reducing valve that supplied the hydraulic fluid accumulated in the pressure accumulation device; a flow rate reduction device; and a controller that controls the flow rate reduction device in accordance with the pressure in the line between the check valve and the control valve drive device.
    Type: Grant
    Filed: March 16, 2015
    Date of Patent: April 30, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Yasutaka Tsuruga, Masatoshi Hoshino, Kiwamu Takahashi
  • Publication number: 20190119886
    Abstract: Provided is a work machine that is equipped with a control unit that executes area limiting control with respect to a work device. The control unit includes: a position computing section that calculates the position, on an operation plane, of the forward end (first reference point) of a bucket and the rear end (second reference point) of the bucket; and a first distance computing section that calculates the distances in the operating plane from the first reference point and the second reference point to the target face A to be controlled. When the smaller one of the two distances is equal to or lower than a threshold during area limiting control, the control unit corrects an operation signal output from an operation lever device so as to reduce the operating speed of a hydraulic actuator that is a control target of the operation signal.
    Type: Application
    Filed: February 28, 2017
    Publication date: April 25, 2019
    Inventors: Shiho IZUMI, Ryuu NARIKAWA, Kouji ISHIKAWA, Daito SAKAI, Takahiko KUROSE
  • Publication number: 20190112996
    Abstract: An object of the present invention is to provide a working machine and a working machine monitoring system using the same which is capable of improving the accuracy in determining fuel property. The working machine is provided with an engine operation parameter acquisition module (1041) that acquires an engine operation parameter representing the operation state of an engine mounted on the working machine; a refueling time acquisition module (1011) that acquires a refueling time when the working machine is supplied with fuel; and a fuel property determination module (1014) that determines the property of the fuel based on a comparison result of the time when the engine operation parameter changes, with the refueling time.
    Type: Application
    Filed: December 13, 2018
    Publication date: April 18, 2019
    Inventors: Shinya SATO, Masatoshi HOSHINO, Kouji ISHIKAWA, Shinji ISHIHARA
  • Publication number: 20190106861
    Abstract: A work machine has a controller which has an area limiting control section correcting the pilot pressures of pilot lines, a regeneration control section adjusting the flow rate of the hydraulic fluid caused to flow from a tank side line of an arm cylinder into a pump side line thereof between zero and a predetermined upper limit value, and a regeneration control switching section that issues an order to the regeneration control section to set the predetermined upper limit value to a first set value when the function of the area limiting control section is invalid and that issues an order to the regeneration control section to set the predetermined upper limit value to a second set value that is smaller than the first set value when the function of the area limiting control section is effective.
    Type: Application
    Filed: February 28, 2017
    Publication date: April 11, 2019
    Inventors: Shiho IZUMI, Ryuu NARIKAWA, Shuuichi MEGURIYA, Tarou AKITA, Kouji ISHIKAWA
  • Patent number: 10253479
    Abstract: When option attachment has not been attached, a reserve flow/direction control valve 8 is made to operate as a center bypass cut valve. When an option attachment has been attached, switching control is performed. In the switching control, when the option attachment is not used, the reserve flow/direction control valve 8 is made to operate as a center bypass cut valve for adjusting composite opening area of a center bypass and thereby controlling the flow rate of hydraulic fluid flowing into an actuator. When the option attachment is used, the reserve flow/direction control valve 8 is made to operate so as to supply the hydraulic fluid to an option hydraulic actuator 14.
    Type: Grant
    Filed: January 9, 2015
    Date of Patent: April 9, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd
    Inventors: Tomoaki Kaneta, Kouji Ishikawa, Hidetoshi Satake, Shinya Imura
  • Patent number: 10227997
    Abstract: To provide a hydraulic drive system for a work machine capable of securing a favorable operability in the case where hydraulic fluid discharged from a hydraulic actuator is regenerated for driving other hydraulic actuator.
    Type: Grant
    Filed: September 16, 2015
    Date of Patent: March 12, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Shinya Imura
  • Patent number: 10221871
    Abstract: The Construction machinery includes at least two actuators, a main pump that generates hydraulic energy for driving the actuators, control valves disposed between the main pump and the actuators, a hydraulic pump motor driven by the generator motor that generates energy to be added to the hydraulic energy, and a controller that reduces hydraulic energy generated by the main pump when the hydraulic pump motor driven by the generator-motor generates energy. The construction machinery further comprises changeover valves that selectively change a location at which the energy from the hydraulic pump motor driven by the generator-motor is to be added according to the actuators. The controller changes a reduction rate of the hydraulic energy generated by the main pump depending on a specific actuator to which the energy is to be added.
    Type: Grant
    Filed: February 1, 2017
    Date of Patent: March 5, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Shinya Imura, Hidetoshi Satake, Kouji Ishikawa, Seiji Hijikata, Takatoshi Ooki, Shinji Nishikawa
  • Publication number: 20190063039
    Abstract: A hydraulic energy regeneration system for a work machine for boosting a pressure of a return hydraulic fluid of a hydraulic cylinder and regenerating the hydraulic fluid, prevents a bottom pressure from reaching an overload relief set pressure and suppresses a changeover shock to ensure favorable operability.
    Type: Application
    Filed: September 23, 2016
    Publication date: February 28, 2019
    Applicant: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji HIJIKATA, Kouji ISHIKAWA, Shinya IMURA
  • Publication number: 20190063041
    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.
    Type: Application
    Filed: February 28, 2017
    Publication date: February 28, 2019
    Inventors: Shiho IZUMI, Shuuichi MEGURIYA, Ryuu NARIKAWA, Kouji ISHIKAWA, Tarou AKITA
  • Patent number: 10161108
    Abstract: Provided is a hydraulic fluid energy recovery system for a work machine equipped with a hydraulic pump, a hydraulic actuator for driving the work machine, an operating device for operating the hydraulic actuator, and a regenerating device for recovering a return fluid flowing back from the hydraulic actuator.
    Type: Grant
    Filed: January 28, 2014
    Date of Patent: December 25, 2018
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Takatoshi Ooki, Shinya Imura
  • Publication number: 20180274208
    Abstract: Provided is a construction machine allowing regeneration of a return hydraulic fluid at the time of both a boom raising operation and a boom lowering operation with a small number of valves, making it possible to secure a satisfactory operability at the time of both the boom raising operation and the boom lowering operation.
    Type: Application
    Filed: September 29, 2015
    Publication date: September 27, 2018
    Inventors: Seiji HIJIKATA, Kouji ISHIKAWA, Shinya IMURA
  • Publication number: 20180266079
    Abstract: An area limit control part as a control section outputs a requested boost pilot pressure for driving a control valve, based upon a pilot pressure in accordance with an operating amount of an operating lever and a posture signal of a posture sensor. A drive permission determination part determines whether or not a drive of a hydraulic actuator is permitted based upon the pilot pressure in accordance with the operating amount of the operating lever. A pilot pressure selecting part selects the requested boost pilot pressure from the area limit control part in such a manner as to drive the control valve with the requested boost pilot pressure to the hydraulic actuator the drive of which is permitted, and not to drive the control valve to the hydraulic actuator the drive of which is not permitted.
    Type: Application
    Filed: March 31, 2016
    Publication date: September 20, 2018
    Inventors: Yuuichirou MORITA, Manabu EDAMURA, Kouji ISHIKAWA
  • Patent number: 10060450
    Abstract: The energy efficiency is increased by reducing the throttle/relief loss in the delivery flow of the hydraulic pump caused by the bleed-off control, while also making it possible to control the delivery pressure of the hydraulic pump according to the operation amount of the control lever unit and improving the operational performance. A controller 6 includes a target pump pressure setting unit 32 which calculates a target pump delivery pressure which increases with the increase in an operation amount signal from an operation amount detector 20A/20B based on the operation amount signal and a pump flow rate upper limit setting unit 33 which calculates a pump flow rate upper limit which increases with the increase in the operation amount signal based on the operation amount signal.
    Type: Grant
    Filed: November 5, 2013
    Date of Patent: August 28, 2018
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Tsutomu Udagawa, Akira Nakayama, Ryohei Yamashita, Shiho Izumi, Manabu Edamura, Kouji Ishikawa, Hidetoshi Satake