Patents by Inventor Kenji Hiraku

Kenji Hiraku 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: 10889964
    Abstract: Provided is a work machine that can selectively establish a closed circuit connection between a single rod-type hydraulic cylinder and a plurality of bidirectional-type hydraulic pumps, the work machine being capable of enhancing responsiveness of the single rod-type hydraulic cylinder when a high-speed lever switching operation is conducted in a state in which a rod pressure of the single rod-type hydraulic cylinder is higher than a bottom pressure. When a bucket lever (70a) is operated to a side of extending the bucket cylinder in a state in which a pressure in a rod chamber (5b) of the bucket cylinder (5) is higher than a pressure in a bottom chamber (5a), a controller (50) opens a rod-side proportional valve (45) and discharges a working fluid in the rod chamber to a working fluid tank (25) such that a differential pressure between the pressure in the rod chamber and the pressure in the bottom chamber is reduced below a switching pressure (Psw) of a flushing valve (33).
    Type: Grant
    Filed: April 6, 2018
    Date of Patent: January 12, 2021
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Juri Shimizu, Kenji Hiraku, Hiromasa Takahashi, Shohei Sugiki
  • Patent number: 10858805
    Abstract: A construction machine is provided which includes a hydraulic closed circuit in which a single rod hydraulic cylinder is driven directly by a bidirectionally tiltable variable displacement pump and can stably speed up the contraction action of the single rod hydraulic cylinder. In the case where a contraction action of a hydraulic cylinder 10 is instructed through an operation lever 30, when a differential pressure obtained by subtracting the pressure of a cap chamber 10a from the pressure of a rod chamber 10b is equal to or lower than a first threshold value a set to a level equal to or higher than a selection setting pressure of a flushing valve 14, a controller 20 closes a rod side selector valve 12b to disable rod assist action for supplying hydraulic fluid from a second hydraulic pump 8 to the rod chamber, and when the differential pressure is higher than the first threshold value, the controller 20 opens the rod side selector valve to enable the rod assist action.
    Type: Grant
    Filed: January 16, 2018
    Date of Patent: December 8, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiromasa Takahashi, Shohei Sugiki, Kenji Hiraku, Juri Shimizu, Teppei Saitoh
  • Patent number: 10829908
    Abstract: This construction machine includes a first hydraulic drive device that is driven by a first prime mover and a second hydraulic drive device that is driven by a second prime mover. The first hydraulic drive device has a first closed circuit that connects a first hydraulic actuator and a first closed-circuit pump and a first assist flow path that connects the first closed circuit and a first open-circuit pump and that supplies pressure oil from the first open-circuit pump to the first closed circuit. The second hydraulic drive device is provided with a second closed circuit that connects a second hydraulic actuator and a second closed-circuit pump. The present invention also includes a first emergency flow path that branches from the first assist flow path and connects to the second closed circuit and that supplies pressure oil from the first open-circuit pump to the second closed circuit.
    Type: Grant
    Filed: November 16, 2017
    Date of Patent: November 10, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Teppei Saitoh, Kenji Hiraku, Juri Shimizu, Hiromasa Takahashi
  • Publication number: 20200291612
    Abstract: Provided is a work machine which makes it possible, in a hydraulic closed-circuit system, to prevent occurrence of cavitation when reverse lever operation which is an instruction for a swing in a direction opposite to a swing direction is performed during swing deceleration. A controller is configured to perform control such that a rate of a flow supplied from a bidirectionally tiltable hydraulic pump to a swing motor becomes lower than a pump flow rate according to an operation amount of the swing operation lever when a swing direction corresponding to a swing velocity sensed at a velocity sensor is different from a swing direction corresponding to operation of a swing operation lever.
    Type: Application
    Filed: November 16, 2018
    Publication date: September 17, 2020
    Inventors: Takamasa KAI, Teppei SAITOU, Kenji HIRAKU, Juri SHIMIZU
  • Patent number: 10745887
    Abstract: A work machine that can detect abnormality such as a malfunction and wear and tear of each of hydraulic pumps including control equipment with high precision and that can reduce equipment cost is provided. A controller 9 according to the present invention includes a volumetric-transfer-efficiency-calculating section 94 that calculates a volumetric transfer efficiency ?C representing a transfer efficiency of hydraulic oil between a hydraulic cylinder 11 and hydraulic pumps 21 to 23 on the basis of a target discharge flow rate calculated by a target-discharge-flow-rate-calculating section 932 and the speed of the hydraulic cylinder 11 that is detected by a speed sensor 28, and an abnormality decision section 95 that decides whether any one of the hydraulic pumps 21 to 23 is abnormal on the basis of the volumetric transfer efficiency ?C calculated by the volumetric-transfer-efficiency-calculating section 94.
    Type: Grant
    Filed: August 29, 2016
    Date of Patent: August 18, 2020
    Assignee: HITACHI CONSTRUCTION MACHINERY CO., LTD.
    Inventors: Yuki Akiyama, Kenji Hiraku, Hiromasa Takahashi
  • Publication number: 20200232488
    Abstract: It is an object of the present invention to provide a hydraulic drive system that effectively utilizes a hydraulic fluid accumulated in an accumulator to make it possible to achieve a substantial improvement in terms of efficiency for a work machine as a whole. A hydraulic drive system includes: a first hydraulic pump; a first hydraulic actuator driven by being supplied with a hydraulic fluid from the first hydraulic pump; a first line for supplying the hydraulic fluid from the first hydraulic pump to the first hydraulic actuator; a first pump flow adjustment device installed in the first line, the first pump flow adjustment device being configured to adjust; a first hydraulic accumulator for accumulating the hydraulic fluid delivered from the first hydraulic pump; and a first accumulation flow adjustment device configured to adjust the flow of the hydraulic fluid from the first hydraulic pump to the first hydraulic accumulator.
    Type: Application
    Filed: September 29, 2016
    Publication date: July 23, 2020
    Inventors: Seiji HIJIKATA, Yasutaka TSURUGA, Kenji HIRAKU, Kouji ISHIKAWA
  • Publication number: 20200212546
    Abstract: The wearable antenna device includes an antenna part—attached to a part of a garment including a body accommodation part—that accommodates a part of a body, and a functional element arranged in a position of the garment in such a way that at least a part of the functional element is opposed to the antenna part with the body accommodation part interposed therebetween.
    Type: Application
    Filed: April 10, 2018
    Publication date: July 2, 2020
    Applicants: NEC CORPORATION, NEC PLATFORMS, LTD.
    Inventors: Shinichirou KODAMA, Kenji KOUNO, Tomohiro SHIMODA, Kazuaki MUROFUSHI, Hidenori MORIYA, Mitsuno KONDO, Sumio HIRAKU, yUKIO ANDO, Tetsuya NAGATA
  • Patent number: 10677272
    Abstract: Provided is a construction machine capable of detecting a stuck-open state of a surplus flow control valve in real time during operation without involving a reduction in the operational speed.
    Type: Grant
    Filed: June 26, 2017
    Date of Patent: June 9, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Teppei Saitoh, Juri Shimizu, Kenji Hiraku, Hiromasa Takahashi, Shouhei Sugiki
  • Patent number: 10655740
    Abstract: A work machine includes a closed circuit system in which there is provided a flushing valve.
    Type: Grant
    Filed: February 25, 2016
    Date of Patent: May 19, 2020
    Assignee: HITACHI CONSTRUCTION MACHINERY CO., LTD.
    Inventors: Juri Shimizu, Teppei Saitoh, Kenji Hiraku, Yuki Akiyama, Hiromasa Takahashi
  • Publication number: 20200131736
    Abstract: Provided is a work machine that can selectively establish a closed circuit connection between a single rod-type hydraulic cylinder and a plurality of bidirectional-type hydraulic pumps, the work machine being capable of enhancing responsiveness of the single rod-type hydraulic cylinder when a high-speed lever switching operation is conducted in a state in which a rod pressure of the single rod-type hydraulic cylinder is higher than a bottom pressure. When a bucket lever (70a) is operated to a side of extending the bucket cylinder in a state in which a pressure in a rod chamber (5b) of the bucket cylinder (5) is higher than a pressure in a bottom chamber (5a), a controller (50) opens a rod-side proportional valve (45) and discharges a working fluid in the rod chamber to a working fluid tank (25) such that a differential pressure between the pressure in the rod chamber and the pressure in the bottom chamber is reduced below a switching pressure (Psw) of a flushing valve (33).
    Type: Application
    Filed: April 6, 2018
    Publication date: April 30, 2020
    Inventors: Juri SHIMIZU, Kenji HIRAKU, Hiromasa TAKAHASHI, Shohei SUGIKI
  • Publication number: 20200115887
    Abstract: A construction machine is provided which includes a hydraulic closed circuit in which a single rod hydraulic cylinder is driven directly by a bidirectionally tiltable variable displacement pump and can stably speed up the contraction action of the single rod hydraulic cylinder. In the case where a contraction action of a hydraulic cylinder 10 is instructed through an operation lever 30, when a differential pressure obtained by subtracting the pressure of a cap chamber 10a from the pressure of a rod chamber 10b is equal to or lower than a first threshold value a set to a level equal to or higher than a selection setting pressure of a flushing valve 14, a controller 20 closes a rod side selector valve 12b to disable rod assist action for supplying hydraulic fluid from a second hydraulic pump 8 to the rod chamber, and when the differential pressure is higher than the first threshold value, the controller 20 opens the rod side selector valve to enable the rod assist action.
    Type: Application
    Filed: January 16, 2018
    Publication date: April 16, 2020
    Inventors: Hiromasa TAKAHASHI, Shohei SUGIKI, Kenji HIRAKU, Juri SHIMIZU, Teppei SAITOH
  • Publication number: 20190345692
    Abstract: A construction machine incorporates a hydraulic closed circuit system capable of suppressing, even where a selector valve is stuck in an open state by a failure of the selector valve or a control system therefor, unintended operation of a hydraulic actuator and continuing operation of a machine body. The construction machine includes first sensors that detect open-closed states of a plurality of switching valves, first compulsory valve closing devices that change over the plurality of switching valves to a closed position irrespective of open-close control by a machine body controller, and a valve device controller that controls, when it is detected based on the open-closed states of the plurality of selector values detected by the first sensors that one of the plurality of selector values is stuck in an open state, the first compulsory valve closing device such that other selector valve connected to one of the plurality of closed circuit pumps to which the one selector valve is connected is closed.
    Type: Application
    Filed: February 6, 2018
    Publication date: November 14, 2019
    Inventors: Teppei SAITOH, Takamasa KAI, Kenji HIRAKU, Hiromasa TAKAHASHI, Juri SHIMIZU
  • Patent number: 10415215
    Abstract: A drive system for a construction machine capable of appropriately controlling a distribution flow rate to each hydraulic actuator and improving operability by an operator is provided.
    Type: Grant
    Filed: December 20, 2017
    Date of Patent: September 17, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiromasa Takahashi, Kenji Hiraku, Juri Shimizu, Shohei Sugiki
  • Patent number: 10378185
    Abstract: To provide a work machine capable of efficiently regenerating the energy owned by hydraulic fluid during a swing deceleration.
    Type: Grant
    Filed: March 10, 2015
    Date of Patent: August 13, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Teppei Saitoh, Yuki Akiyama, Kenji Hiraku, Hiromasa Takahashi, Juri Shimizu
  • Patent number: 10370824
    Abstract: To provide a work machine which, in a configuration provided with a closed-circuit pump and an open-circuit pump, is capable of stabilizing respective pump operations of the closed-circuit pump and the open-circuit pump and of improving the mountability of the closed-circuit pump and the open-circuit pump. The present invention is provided with a closed circuit in which a closed-circuit pump and a boom cylinder are connected annularly, and an open circuit which has an open-circuit pump for making hydraulic fluid flow in from a reservoir and flow out and a connection passage capable of introducing hydraulic fluid into the closed circuit, wherein the closed-circuit pump is installed above the open-circuit pump.
    Type: Grant
    Filed: March 13, 2015
    Date of Patent: August 6, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kenji Hiraku, Hiromasa Takahashi
  • Publication number: 20190218750
    Abstract: This construction machine includes a first hydraulic drive device that is driven by a first prime mover and a second hydraulic drive device that is driven by a second prime mover. The first hydraulic drive device has a first closed circuit that connects a first hydraulic actuator and a first closed-circuit pump and a first assist flow path that connects the first closed circuit and a first open-circuit pump and that supplies pressure oil from the first open-circuit pump to the first closed circuit. The second hydraulic drive device is provided with a second closed circuit that connects a second hydraulic actuator and a second closed-circuit pump. The present invention also includes a first emergency flow path that branches from the first assist flow path and connects to the second closed circuit and that supplies pressure oil from the first open-circuit pump to the second closed circuit.
    Type: Application
    Filed: November 16, 2017
    Publication date: July 18, 2019
    Inventors: Teppei SAITOH, Kenji HIRAKU, Juri SHIMIZU, Hiromasa TAKAHASHI
  • Publication number: 20190218987
    Abstract: In a drive unit of a fuel injection device, an electric current is supplied to the fuel injection device by applying a high voltage to the fuel injection device from a high voltage source whose voltage is boosted to a voltage higher than a battery voltage at the time of opening a valve of the fuel injection device. Thereafter, the electric current supplied to the fuel injection device is lowered to a current value at which a valve element cannot be held in a valve open state by stopping the applying of the high voltage from the high voltage source. Thereafter, in a stage where a supply current is switched to a hold current, another high voltage is applied to the fuel injection device from the high voltage source.
    Type: Application
    Filed: March 27, 2019
    Publication date: July 18, 2019
    Applicant: Hitachi Automotive Systems, Ltd.
    Inventors: Ryo KUSAKABE, Motoyuki ABE, Hideharu EHARA, Tohru ISHIKAWA, Takuya MAYUZUMI, Kenji HIRAKU
  • Patent number: 10280862
    Abstract: In a drive unit of a fuel injection device, an electric current is supplied to the fuel injection device by applying a high voltage to the fuel injection device from a high voltage source whose voltage is boosted to a voltage higher than a battery voltage at the time of opening a valve of the fuel injection device. Thereafter, the electric current supplied to the fuel injection device is lowered to a current value at which a valve element cannot be held in a valve open state by stopping the applying of the high voltage from the high voltage source. Thereafter, in a stage where a supply current is switched to a hold current, another high voltage is applied to the fuel injection device from the high voltage source.
    Type: Grant
    Filed: February 13, 2017
    Date of Patent: May 7, 2019
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Ryo Kusakabe, Motoyuki Abe, Hideharu Ehara, Tohru Ishikawa, Takuya Mayuzumi, Kenji Hiraku
  • Publication number: 20190078594
    Abstract: Provided is a construction machine capable of detecting a stuck-open state of a surplus flow control valve in real time during operation without involving a reduction in the operational speed.
    Type: Application
    Filed: June 26, 2017
    Publication date: March 14, 2019
    Applicant: Hitachi Constuction Machinery Co., Ltd.
    Inventors: Teppei SAITOH, Juri SHIMIZU, Kenji HIRAKU, Hiromasa TAKAHASHI, Shouhei SUGIKI
  • Patent number: 10184225
    Abstract: Closed circuit lines (33, 43, 53, 63) for connecting hydraulic cylinders (17, 18, 19) and closed circuit pumps (31, 41, 51, 61) are provided with a charge pressure adjustment apparatus (75) via a charge line (72) to variably adjust the pressure in the charge line (72). An operating device (12) for operating the hydraulic cylinders (17, 18, 19) and the charge pressure adjustment apparatus (75) are connected to a control device (81). In the case of extending the hydraulic cylinders (17, 18, 19), the control device (81) increases a set pressure of the charge pressure adjustment apparatus (75) to be high to increase the pressure in the bottom side of the hydraulic cylinders (17, 18, 19) in accordance with an operating amount of the operating device (12).
    Type: Grant
    Filed: December 22, 2015
    Date of Patent: January 22, 2019
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Kenji Hiraku, Teppei Saitoh