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: 11319693
    Abstract: To make it possible to prevent a decrease in work speed due to a decrease in the speed of a given actuator when an operator unintentionally performs a fine operation of the control lever of the other actuator in a state in which the given actuator is driven by the hydraulic fluid delivered from a plurality of pumps, a controller (41) sets, as a composite dead zone line serving as a boundary of a composite dead zone, a composite dead zone line such that as an operation amount in one direction of a control lever (12L) or (13L) of a control lever device (12) or (13) is increased, the width of the composite dead zone corresponding to an operation amount in the other direction of the control lever is widened, and corrects the operation amount in the other direction such that the demanded flow rate of an actuator increases from zero, when the control lever is operated in the other direction in a state in which the operation amount in the one direction of the control lever remains within a range of the composite dea
    Type: Grant
    Filed: February 18, 2020
    Date of Patent: May 3, 2022
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Hiromasa Takahashi, Kenji Hiraku, Teppei Saitoh, Syouhei Sugiki
  • Publication number: 20220074170
    Abstract: To provide a construction machine that has a hydraulic system mounted thereon in which a closed-circuit pump, and an open-circuit pump and a proportional valve are arranged as a pair, and that makes it possible to use an unused open-circuit pump or proportional valve to accelerate the speed of a single rod hydraulic cylinder when the single rod hydraulic cylinder and a hydraulic motor are driven simultaneously. A controller (51) controls a cap-side selector valve (46) and a rod-side selector valve (47) such that a particular open-circuit pump (15) not connected to a single rod hydraulic cylinder (3) is connected to the single rod hydraulic cylinder, and controls an opening area of a particular proportional valve (49) provided on a flow line that connects a delivery port of the particular open-circuit pump to a tank, when the single rod hydraulic cylinder and a hydraulic motor (7) are driven simultaneously.
    Type: Application
    Filed: February 12, 2020
    Publication date: March 10, 2022
    Inventors: Takamasa KAI, Juri SHIMIZU, Kenji HIRAKU, Hiromasa TAKAHASHI, Teppei SAITOU
  • Publication number: 20220056667
    Abstract: Provided is a construction machine on which a hydraulic closed circuit for driving a single rod-type hydraulic cylinder and a swing hydraulic motor is mounted and that has good swing deceleration responsiveness. In this construction machine that drives each of a single rod-type hydraulic cylinder and a swing hydraulic motor in a closed circuit, a minimum passage area from a second flushing valve to a tank in a case the second flushing valve is fully open is smaller than a minimum passage area from a first flushing valve to the tank in a case the first flushing valve is fully open.
    Type: Application
    Filed: November 5, 2019
    Publication date: February 24, 2022
    Inventors: Teppei SAITOH, Hiromasa TAKAHASHI, Kenji HIRAKU
  • Publication number: 20220042279
    Abstract: To make it possible to prevent a decrease in work speed due to a decrease in the speed of a given actuator when an operator unintentionally performs a fine operation of the control lever of the other actuator in a state in which the given actuator is driven by the hydraulic fluid delivered from a plurality of pumps, a controller (41) sets, as a composite dead zone line serving as a boundary of a composite dead zone, a composite dead zone line such that as an operation amount in one direction of a control lever (12L) or (13L) of a control lever device (12) or (13) is increased, the width of the composite dead zone corresponding to an operation amount in the other direction of the control lever is widened, and corrects the operation amount in the other direction such that the demanded flow rate of an actuator increases from zero, when the control lever is operated in the other direction in a state in which the operation amount in the one direction of the control lever remains within a range of the composite dea
    Type: Application
    Filed: February 18, 2020
    Publication date: February 10, 2022
    Inventors: Hiromasa TAKAHASHI, Kenji HIRAKU, Teppei SAITOH, Syouhei SUGIKI
  • Patent number: 11214941
    Abstract: It is an object of the present invention to provide a construction machine having a good engine starting property in a low temperature environment. The construction machine of the present invention includes: an electric pump having a delivery port connected to a line part of a pilot line, the line part connecting a pilot pump with a pilot control valve; a motor that drives the electric pump; and a temperature sensor that measures a temperature of a hydraulic working fluid delivered from the pilot pump. A controller starts driving of the motor in the case where a key switch is operated from a key OFF state to a key ON state and where the temperature of the hydraulic working fluid measured by the temperature sensor is lower than a predetermined temperature.
    Type: Grant
    Filed: March 28, 2019
    Date of Patent: January 4, 2022
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Teppei Saitoh, Kenji Hiraku, Mitsuo Aihara
  • Patent number: 11118328
    Abstract: An object of the present invention is to provide a construction machine capable of suppressing lugging down of an engine irrespective of contents of operation of an operator and the load state of a hydraulic actuator.
    Type: Grant
    Filed: May 20, 2019
    Date of Patent: September 14, 2021
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Juri Shimizu, Kenji Hiraku, Hiromasa Takahashi, Teppei Saitou, Shouhei Sugiki
  • Patent number: 11111651
    Abstract: An object of the present invention is to provide a construction machine that has a hydraulic closed-circuit system mounted therein and capable of selectively connecting some of a plurality of hydraulic pumps driven by two engines to any one of a plurality of hydraulic actuators and that can downsize the engines while maintaining high work efficiency.
    Type: Grant
    Filed: May 20, 2019
    Date of Patent: September 7, 2021
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Juri Shimizu, Kenji Hiraku, Hiromasa Takahashi, Teppei Saitou
  • Publication number: 20210262201
    Abstract: It is an object of the present invention to provide a construction machine having a good engine starting property in a low temperature environment. The construction machine of the present invention includes: an electric pump having a delivery port connected to a line part of a pilot line, the line part connecting a pilot pump with a pilot control valve; a motor that drives the electric pump; and a temperature sensor that measures a temperature of a hydraulic working fluid delivered from the pilot pump. A controller starts driving of the motor in the case where a key switch is operated from a key OFF state to a key ON state and where the temperature of the hydraulic working fluid measured by the temperature sensor is lower than a predetermined temperature.
    Type: Application
    Filed: March 28, 2019
    Publication date: August 26, 2021
    Inventors: Teppei SAITOH, Kenji HIRAKU, Mitsuo AIHARA
  • Publication number: 20210246634
    Abstract: An object of the present invention is to provide a construction machine capable of suppressing lugging down of an engine irrespective of contents of operation of an operator and the load state of a hydraulic actuator.
    Type: Application
    Filed: May 20, 2019
    Publication date: August 12, 2021
    Inventors: Juri SHIMIZU, Kenji HIRAKU, Hiromasa TAKAHASHI, Teppei SAITOU, Shouhei SUGIKI
  • Publication number: 20210230839
    Abstract: An object of the present invention is to provide a construction machine that has a hydraulic closed-circuit system mounted therein and capable of selectively connecting some of a plurality of hydraulic pumps driven by two engines to any one of a plurality of hydraulic actuators and that can downsize the engines while maintaining high work efficiency.
    Type: Application
    Filed: May 20, 2019
    Publication date: July 29, 2021
    Inventors: Juri SHIMIZU, Kenji HIRAKU, Hiromasa TAKAHASHI, Teppei SAITOU
  • Patent number: 10947699
    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: Grant
    Filed: February 6, 2018
    Date of Patent: March 16, 2021
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Teppei Saitoh, Takamasa Kai, Kenji Hiraku, Hiromasa Takahashi, Juri Shimizu
  • Patent number: 10914053
    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: Grant
    Filed: November 16, 2018
    Date of Patent: February 9, 2021
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Takamasa Kai, Teppei Saitou, Kenji Hiraku, Juri Shimizu
  • Patent number: 10907666
    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: Grant
    Filed: September 29, 2016
    Date of Patent: February 2, 2021
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Seiji Hijikata, Yasutaka Tsuruga, Kenji Hiraku, Kouji Ishikawa
  • Patent number: 10900435
    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: March 27, 2019
    Date of Patent: January 26, 2021
    Assignee: HITACHI AUTOMOTIVE SYSTEMS, LTD.
    Inventors: Ryo Kusakabe, Motoyuki Abe, Hideharu Ehara, Tohru Ishikawa, Takuya Mayuzumi, Kenji Hiraku
  • 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