Patents by Inventor Seiji Hijikata

Seiji Hijikata 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).

  • Patent number: 10584722
    Abstract: A hydraulic fluid energy regeneration apparatus of a work machine includes: a regeneration hydraulic motor driven by a return hydraulic fluid; a first hydraulic pump mechanically connected to the regeneration hydraulic motor; a second hydraulic pump that delivers a hydraulic fluid for driving a hydraulic actuator; a confluence line that causes the hydraulic fluid delivered from the first hydraulic pump to join the hydraulic fluid delivered from the second hydraulic pump; a first adjuster configured to adjust the flow rate of the hydraulic fluid of the first hydraulic pump; and a second adjuster configured to adjust the delivery flow rate of the second hydraulic pump.
    Type: Grant
    Filed: September 29, 2015
    Date of Patent: March 10, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Takatoshi Ooki, Shinya Imura
  • Publication number: 20200056349
    Abstract: Provided is a work machine capable of regenerating a return hydraulic fluid from a hydraulic actuator while preventing a drag loss of a regeneration hydraulic motor and a hydraulic pump from increasing and preventing the regeneration efficiency of the regeneration hydraulic motor from decreasing. A controller 100 computes a required regeneration hydraulic motor revolution speed from a displacement of a regeneration hydraulic motor 13 and a regeneration flow rate of the regeneration hydraulic motor, computes a required first hydraulic pump revolution speed from a displacement of a first hydraulic pump 15 and a target assist flow rate of the first hydraulic pump, and selects a greater one of the required regeneration hydraulic motor revolution speed and the required first hydraulic pump revolution speed as a target revolution speed of an electric motor 14.
    Type: Application
    Filed: March 8, 2018
    Publication date: February 20, 2020
    Inventors: Seiji HIJIKATA, Kouji ISHIKAWA, Shinya IMURA
  • Publication number: 20200032485
    Abstract: A hydraulic circuit (11) of a hydraulic excavator (1) is provided with a main hydraulic circuit (11A) including a boom cylinder (5D), a pilot hydraulic circuit (11B) for operating the boom cylinder (5D) and a recovery hydraulic circuit (11C) including an accumulator (29). In this case, the recovery hydraulic circuit (11C) is provided with a recovery control valve (31) that recovers pressurized oil discharged from the boom cylinder (5D) to the accumulator (29), a main supply control valve (34) for supplying pressurized oil accumulated in the accumulator (29) to the main hydraulic circuit (11A) and a pilot supply control valve (37) for supplying pressurized oil accumulated in the accumulator (29) to the pilot hydraulic circuit (11B).
    Type: Application
    Filed: May 18, 2018
    Publication date: January 30, 2020
    Inventors: Seiji HIJIKATA, Yasutaka TSURUGA, Kouji ISHIKAWA, Kiwamu TAKAHASHI, Masatoshi HOSHINO
  • Patent number: 10526767
    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: Grant
    Filed: September 29, 2015
    Date of Patent: January 7, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Shinya Imura
  • Patent number: 10526768
    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: Grant
    Filed: September 23, 2016
    Date of Patent: January 7, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Shinya Imura
  • Patent number: 10436229
    Abstract: Provided is a hydraulic drive system for a work machine configured with a single solenoid proportional valve for a regeneration circuit, wherein substantially the same actuator speed can be secured irrespective of whether or not hydraulic fluid discharged from a hydraulic actuator is regenerated for driving of another hydraulic actuator.
    Type: Grant
    Filed: September 29, 2015
    Date of Patent: October 8, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Shinya Imura
  • Patent number: 10364550
    Abstract: Disclosed is a hydraulic drive system capable of improving the fuel efficiency of a work machine by reducing the pressure loss and drag loss of a hydraulic pump. There are provided an electric motor M; a third pump P3 driven by the electric motor; a third pump hydraulic line L3 to which the delivered hydraulic fluid from the third pump is supplied; a third directional control valve V4 provided in the third pump hydraulic line, switch-operated by an arm operation device 19, and controlling the flow rate of the hydraulic fluid supplied to the arm cylinder 8 from the third hydraulic pump; and a controller 18 drive-controlling the electric motor, wherein the controller drives the third pump by the electric motor when a swing/arm combined operation is detected by pilot pressure sensors S6, S7, S10, S11.
    Type: Grant
    Filed: February 22, 2016
    Date of Patent: July 30, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiroaki Amano, Kouji Ishikawa, Shinya Imura, Hidekazu Moriki, Ryohei Yamashita, Seiji Hijikata
  • Patent number: 10344458
    Abstract: A hydraulic drive system 100A for a work machine includes: a boom cylinder 4; an arm cylinder 8; a hydraulic pump device 51; a control valve 5; a regenerative device 61; a first operation device 41; a second operation device 42; a sensor device 71; and a controller 27. The sensor device 71 includes at least one of pressure sensors 23, 24, 25, and 26. The controller 27 includes an abnormality detection part 142 and a first control part. The abnormality detection part 142 determines whether or not the sensor device 71 is abnormal. If the sensor device 71 is abnormal, the first control part controls the regenerative device 61 such that the hydraulic fluid returning from the boom cylinder 4 is not supplied to the arm cylinder 8 even if the values measured by the sensor device 71 satisfy regenerative conditions.
    Type: Grant
    Filed: June 1, 2016
    Date of Patent: July 9, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Kouji Ishikawa, Shinya Imura
  • Patent number: 10329739
    Abstract: The invention provides a construction machine in which the load torque at the time of engine start-up can be reduced even when the engine stops against the will of the operator. A hydraulic excavator includes a control device (35) having a pump displacement control section (37) and an unload control section (38). The pump displacement control section (37) makes the displacement of a hydraulic pump (16) variable to a minimum displacement by controlling a regulator device (20) when the speed of an engine (14) detected by a speed sensor (41) becomes equal to or less than a preset low speed N3 at the time of driving of the engine (14). The unload control section (40) controls an unloading valve (24) to the open position at the time of start-up of the engine (14).
    Type: Grant
    Filed: March 11, 2016
    Date of Patent: June 25, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Masatoshi Hoshino, Yasutaka Tsuruga, Kiwamu Takahashi, Seiji Hijikata
  • Publication number: 20190186106
    Abstract: A work machine including: a hydraulic cylinder 20 configured to drive a work implement 3; a control valve 22 configured to connect a delivery line of a hydraulic pump 21 switchingly to a bottom fluid chamber and a rod fluid chamber of the hydraulic cylinder 20 and a tank; a pilot pump 23 configured to output a pilot pressure to drive the control valve 22; an engine 24 configured to drive the hydraulic pump 21 and the pilot pump 23; and an accumulator 26 configured to accumulate a return hydraulic fluid from the hydraulic cylinder 20 is provided with: a bypass line 41 configured to connect the bottom fluid chamber of the hydraulic cylinder 20 and a delivery line 21a of the hydraulic pump 21 by bypassing the control valve 22 and be provided with the accumulator 26 thereon; a pressure-accumulation control valve 27 provided between the bottom fluid chamber of the hydraulic cylinder 20 and the accumulator 26; a release control valve 28 provided between the accumulator 26 and the delivery line 21a; and a hydraulic
    Type: Application
    Filed: March 29, 2017
    Publication date: June 20, 2019
    Inventors: Yuichi OGAWA, Seiji HIJIKATA, Masatoshi HOSHINO, Kiwamu TAKAHASHI, Kouji ISHIKAWA
  • 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: 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
  • 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: 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
  • 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
  • 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
  • Patent number: 10066368
    Abstract: The hydraulic fluid energy recovery apparatus includes a fluid communication line for holding a bottom-side hydraulic fluid chamber and a rod-side hydraulic fluid chamber of a hydraulic cylinder in fluid communication with each other, a fluid communication valve connected to the fluid communication line for adjusting the pressure and/or flow rate of a hydraulic fluid passing through the fluid communication line in a manner that allows for adjustment of a degree of opening of the fluid communication valve, first pressure detecting means for detecting a signal indicative of pressure at the bottom-side hydraulic fluid chamber of the hydraulic cylinder, an amount-of-operation detecting means for detecting an amount of operation of the operating means, and a control device for capturing the signal of pressure at the bottom-side hydraulic fluid chamber of the hydraulic cylinder detected by the first pressure detecting means.
    Type: Grant
    Filed: January 16, 2014
    Date of Patent: September 4, 2018
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Hidetoshi Satake, Shinya Imura, Shinji Nishikawa