Patents by Inventor Teppei Saitoh

Teppei Saitoh 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: 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
  • 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
  • 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: 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
  • 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: 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: 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
  • 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
  • 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