Patents by Inventor Juri Shimizu

Juri Shimizu 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: 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: 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: 10767674
    Abstract: A construction machine includes a bidirectionally tiltable type hydraulic pump 2, a hydraulic cylinder 1 having a cap chamber 1e and a rod chamber 1f, a first flow path 11 connecting the hydraulic pump 2 and the cap chamber 1e, a second flow path 12 connecting the hydraulic pump 2 and the rod chamber 1f, a discharge flow path 16 branched from the first flow path 11, a discharge valve 32 that is disposed in the discharge flow path 16 and controls a discharge rate of hydraulic working oil from the cap chamber 1e to the discharge flow path 16, an operation device 54 that instructs an action of the hydraulic cylinder 1, and a controller 56.
    Type: Grant
    Filed: November 7, 2017
    Date of Patent: September 8, 2020
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Takamasa Kai, Hiromasa Takahashi, Teppei Saitoh, Juri Shimizu
  • 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: 20190352884
    Abstract: A construction machine includes a bidirectionally tiltable type hydraulic pump 2, a hydraulic cylinder 1 having a cap chamber 1e and a rod chamber 1f, a first flow path 11 connecting the hydraulic pump 2 and the cap chamber 1e, a second flow path 12 connecting the hydraulic pump 2 and the rod chamber 1f, a discharge flow path 16 branched from the first flow path 11, a discharge valve 32 that is disposed in the discharge flow path 16 and controls a discharge rate of hydraulic working oil from the cap chamber 1e to the discharge flow path 16, an operation device 54 that instructs an action of the hydraulic cylinder 1, and a controller 56.
    Type: Application
    Filed: November 7, 2017
    Publication date: November 21, 2019
    Inventors: Takamasa KAI, Hiromasa TAKAHASHI, Teppei SAITOH, Juri SHIMIZU
  • 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
  • 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: 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
  • Publication number: 20180251960
    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: Application
    Filed: December 20, 2017
    Publication date: September 6, 2018
    Inventors: Hiromasa TAKAHASHI, Kenji HIRAKU, Juri SHIMIZU, Shohei SUGIKI
  • Publication number: 20180135764
    Abstract: A work machine includes a closed circuit system in which there is provided a flushing valve.
    Type: Application
    Filed: February 25, 2016
    Publication date: May 17, 2018
    Inventors: Juri SHIMIZU, Teppei SAITOH, Kenji HIRAKU, Yuki AKIYAMA, Hiromasa TAKAHASHI
  • Patent number: 9879405
    Abstract: To provide a hydraulic driving device configured to smoothly extend a hydraulic cylinder. The present invention includes the open circuit E, the closed circuit A, a control device 57, and a control lever 56a. The open circuit E is provided with a flow passage 202 for connecting an outlet port of the open circuit pump 13 and a head chamber 1a of the boom cylinder 1, a selector valve 44a provided in the flow passage 202, a discharge flow passage 404 for connecting a hydraulic fluid tank 25 and a flow passage 200, and a bleed-off valve 64 provided in the discharge flow passage 404. The control device 57 is configured in such a manner that when a manipulate signal for extending the boom cylinder 1 is input from the control lever 56a, the bleed-off valve 64 is closed, the selector valve 44a is subsequently opened, and the open circuit pump 13 is controlled.
    Type: Grant
    Filed: March 18, 2015
    Date of Patent: January 30, 2018
    Assignee: Hitachi Construction Machinery Co., Ltd.
    Inventors: Teppei Saitoh, Juri Shimizu, Mariko Mizuochi, Kenji Hiraku, Akinori Ishii, Hiromasa Takahashi