Patents by Inventor Naoki Tadokoro

Naoki Tadokoro 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: 11780071
    Abstract: There is provided a power tool in which impact applied to a power transmission portion can be mitigated to thereby suppress components constituting the power transmission portion from being deformed and damaged. The power tool includes a brushless motor 3 having a rotation shaft portion 31 rotatable about a rotation axis A1, a housing 2 accommodating therein the brushless motor 3, a power transmission portion 6 configured to receive a rotation force of the rotation shaft portion 31 and to transmit a driving force based on the rotation force, and a driven portion 7 configured to be driven by receiving the transmitted driving force. The rotation shaft portion 31 is supported by the housing 2 so as to be movable relative to the housing 2 in an axial direction of the rotation axis A1.
    Type: Grant
    Filed: November 30, 2018
    Date of Patent: October 10, 2023
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Yasutaka Shimizu, Yoshikazu Yokoyama, Naoki Tadokoro, Ryosuke Nakano
  • Patent number: 11766773
    Abstract: There is provided a power tool including a housing, a brushless motor, a power supply circuit, and a fan. The housing is formed with an inlet hole and an exhaust hole. The brushless motor is supported by the housing. The power supply circuit includes at least one circuit element for supplying electric power of a power source to the brushless motor. The fan is driven by rotation of the brushless motor to generate a cooling air flow that flows from the inlet hole to the exhaust hole in the housing. The housing includes a first housing including a grip portion and supporting the brushless motor. The inlet hole is formed in the first housing. The at least one circuit element is disposed inside the first housing and is cooled by the cooling air flow.
    Type: Grant
    Filed: November 30, 2018
    Date of Patent: September 26, 2023
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Naoki Tadokoro, Ken Inui
  • Publication number: 20210187722
    Abstract: There is provided a power tool in which impact applied to a power transmission portion can be mitigated to thereby suppress components constituting the power transmission portion from being deformed and damaged. The power tool includes a brushless motor 3 having a rotation shaft portion 31 rotatable about a rotation axis A1, a housing 2 accommodating therein the brushless motor 3, a power transmission portion 6 configured to receive a rotation force of the rotation shaft portion 31 and to transmit a driving force based on the rotation force, and a driven portion 7 configured to be driven by receiving the transmitted driving force. The rotation shaft portion 31 is supported by the housing 2 so as to be movable relative to the housing 2 in an axial direction of the rotation axis A1.
    Type: Application
    Filed: November 30, 2018
    Publication date: June 24, 2021
    Applicant: KOKI HOLDINGS CO., LTD.
    Inventors: Yasutaka SHIMIZU, Yoshikazu YOKOYAMA, Naoki TADOKORO, Ryosuke NAKANO
  • Publication number: 20210060754
    Abstract: There is provided a power tool including a housing, a brushless motor, a power supply circuit, and a fan. The housing is formed with an inlet hole and an exhaust hole. The brushless motor is supported by the housing. The power supply circuit includes at least one circuit element for supplying electric power of a power source to the brushless motor. The fan is driven by rotation of the brushless motor to generate a cooling air flow that flows from the inlet hole to the exhaust hole in the housing. The housing includes a first housing including a grip portion and supporting the brushless motor. The inlet hole is formed in the first housing. The at least one circuit element is disposed inside the first housing and is cooled by the cooling air flow.
    Type: Application
    Filed: November 30, 2018
    Publication date: March 4, 2021
    Applicant: KOKI HOLDINGS CO., LTD.
    Inventors: Naoki TADOKORO, Ken INUI
  • Patent number: 10903775
    Abstract: It is an object of the invention to provide a power tool capable of performing a control process for avoiding an operation of a protection function for protecting a motor against an overload, unlike the conventional power tool. The control unit detects current I flowing in the motor and determines whether current I exceeds I1 or not (S2). When current I exceeds I1 (S2: Yes), the control unit starts a duty ratio adjustment mode. When current I exceeds Imax (S4: Yes), the control unit accords a protection priority over the adjustment of the duty ratio and stops supplying power to the motor (S5). If current I does not exceed Imax (S4: No), the duty ratio is decreased (S7). When current I becomes lower than I2 (S8: Yes), the control unit increases the duty ratio (S10).
    Type: Grant
    Filed: October 23, 2013
    Date of Patent: January 26, 2021
    Assignee: Koki Holdings Co., Ltd.
    Inventors: Nobuhito Hosokawa, Naoki Tadokoro
  • Patent number: 10505473
    Abstract: An electric tool including a motor configured to be driven by a PWM control of a semiconductor switching element by using a power supply, a power transmission mechanism configured to transmit a rotation of the motor to an end tool, and a controller configured to control a rotation of the motor by a duty ratio of a PWM signal, wherein the controller is configured to set the duty ratio to a reference duty ratio less than 100% when a voltage of the power supply applied to the electric tool is within a predetermined range including a rated voltage of the electric tool, and wherein the controller is configured to drive the motor by setting the duty ratio to be higher than the reference duty ratio when the voltage of the power supply applied to the electric tool is lower than the predetermined range.
    Type: Grant
    Filed: March 25, 2015
    Date of Patent: December 10, 2019
    Assignee: KOKI HOLDINGS CO., LTD.
    Inventors: Nobuhiro Takano, Kazutaka Iwata, Toshiaki Koizumi, Naoki Tadokoro, Hiroshi Haga, Shinichirou Satou
  • Patent number: 9871424
    Abstract: In the present invention, a housing having a trunk part accommodating therein a brushless motor and an output part to which a tip tool is to be connected, a handle part having one end connected to the trunk part, and an accommodation part provided at an other end of the handle part is used, and a FET serving as a switching element that supplies power to the motor is accommodated in the accommodation part from which a power supply cord is pulled out. It is possible to reduce the length of the trunk part in the front-rear direction compared to a case where the FET is disposed in the front-rear direction of the motor.
    Type: Grant
    Filed: January 31, 2014
    Date of Patent: January 16, 2018
    Assignee: HITACHI KOKI CO., LTD.
    Inventor: Naoki Tadokoro
  • Publication number: 20170312902
    Abstract: A powered working machine (10) with which the transmission of vibrations from a housing to a control substrate can be suppressed, operates a distal tool using power from a brushless motor (30), is configured to have: a control substrate (71) that controls the brushless motor (30); a substrate case (82) that accommodates the control substrate (71); a motor housing (20) and cover (160) that support the substrate case (82); an elastic body (152) that is disposed between the substrate case (82) and the motor housing (20); and an elastic body (153) that is disposed between the substrate case (82) and the cover (160).
    Type: Application
    Filed: October 21, 2015
    Publication date: November 2, 2017
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Yuta NOGUCHI, Kazutaka IWATA, Kazuhiko FUNABASHI, Tomoaki SUDO, Ken INUI, Naoki TADOKORO
  • Patent number: 9768713
    Abstract: An electric tool includes a brushless motor and an output part, which is driven by the brushless motor and to which a tip tool is mounted, and a tumbler switch. The tumbler switch applies, to the control unit, a stop signal for stopping the brushless motor at a neutral position, a forward rotation signal for forward rotating the brushless motor by an operation in a first direction, and a reverse rotation signal for reversely rotating the brushless motor by an operation in a second direction.
    Type: Grant
    Filed: August 26, 2014
    Date of Patent: September 19, 2017
    Assignee: HITACHI KOKI CO., LTD.
    Inventors: Toshiaki Koizumi, Naoki Tadokoro, Kazutaka Iwata, Eiji Nakayama
  • Publication number: 20170070168
    Abstract: An electric tool including a motor configured to be driven by a PWM control of a semiconductor switching element by using a power supply, a power transmission mechanism configured to transmit a rotation of the motor to an end tool, and a controller configured to control a rotation of the motor by a duty ratio of a PWM signal, wherein the controller is configured to set the duty ratio to a reference duty ratio less than 100% when a voltage of the power supply applied to the electric tool is within a predetermined range including a rated voltage of the electric tool, and wherein the controller is configured to drive the motor by setting the duty ratio to be higher than the reference duty ratio when the voltage of the power supply applied to the electric tool is lower than the predetermined range.
    Type: Application
    Filed: March 25, 2015
    Publication date: March 9, 2017
    Inventors: Nobuhiro Takano, Kazutaka Iwata, Toshiaki Koizumi, Naoki Tadokoro, Hiroshi Haga, Shinichirou Satou
  • Patent number: 9457459
    Abstract: A power tool includes a motor, an impact mechanism, an output unit, a circuit board, a housing, and a power cord. The circuit board includes a power-source circuit board configured to convert alternate current into direct current and a control circuit board. The housing includes a body section, a board accommodating section, and a handle section. The board accommodating section accommodates the circuit board. The handle section has one end portion connected to the body section and another end portion connected to the board accommodating section. The power cord extends from the board accommodating section. The power cord is positioned opposed to the handle section with respect to the board accommodating section. The control circuit board is located at a position close to the handle section in the board accommodating section. The power-source circuit board is located between the control circuit board and the power cord.
    Type: Grant
    Filed: December 27, 2011
    Date of Patent: October 4, 2016
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Naoki Tadokoro, Ken Miyazawa, Hajime Kikuchi, Toshiaki Koizumi
  • Publication number: 20160204718
    Abstract: An electric tool includes a brushless motor and an output part, which is driven by the brushless motor and to which a tip tool is mounted, and a tumbler switch. The tumbler switch applies, to the control unit, a stop signal for stopping the brushless motor at a neutral position, a forward rotation signal for forward rotating the brushless motor by an operation in a first direction, and a reverse rotation signal for reversely rotating the brushless motor by an operation in a second direction.
    Type: Application
    Filed: August 26, 2014
    Publication date: July 14, 2016
    Inventors: Toshiaki Koizumi, Naoki Tadokoro, Kazutaka Iwata, Eiji Nakayama
  • Publication number: 20160144411
    Abstract: A washer includes: a tank which stores washer fluid; a pump which pressurizes the wash fluid supplied from the tank; a main body including an electric-powered motor which is a driving source of the pump and a battery pack which is a power source of the electric-powered motor; a spray device including a nozzle; and a pressure-resistant hose which connects the main body with the spray device. A discharge pressure (A) of the washer fluid is 0.5 [MPa] or higher and 9.0 [MPa] or lower, and a pressure liquid volume ratio (A/B) which is a ratio of a discharge volume (B) of the washer fluid with respect to the discharge pressure (A) of the washer fluid is 1.8 or larger.
    Type: Application
    Filed: August 7, 2014
    Publication date: May 26, 2016
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Noriyuki HORIE, Naoki TADOKORO
  • Publication number: 20150364973
    Abstract: In the present invention, a housing having a trunk part accommodating therein a brushless motor and an output part to which a tip tool is to be connected, a handle part having one end connected to the trunk part, and an accommodation part provided at an other end of the handle part is used, and a FET serving as a switching element that supplies power to the motor is accommodated in the accommodation part from which a power supply cord is pulled out. It is possible to reduce the length of the trunk part in the front-rear direction compared to a case where the FET is disposed in the front-rear direction of the motor.
    Type: Application
    Filed: January 31, 2014
    Publication date: December 17, 2015
    Inventor: Naoki Tadokoro
  • Publication number: 20150352699
    Abstract: A power tool includes a housing, a motor, a hammer, an anvil, and a controller. The motor is accommodated in the housing. The hammer is configured to be rotated by the motor. The anvil is configured to be rotated in one of a rotational mode in which the anvil is rotated together with the hammer and a striking mode in which the anvil is rotated upon being struck by the hammer. The controller is configured to control the motor to be braked in the striking mode.
    Type: Application
    Filed: January 15, 2014
    Publication date: December 10, 2015
    Inventors: Hironori SAKAI, Naoki TADOKORO
  • Publication number: 20150349695
    Abstract: It is an object of the invention to provide a power tool capable of performing a control process for avoiding an operation of a protection function for protecting a motor against an overload, unlike the conventional power tool. The control unit detects current I flowing in the motor and determines whether current I exceeds I1 or not (S2). When current I exceeds I1 (S2: Yes), the control unit starts a duty ratio adjustment mode. When current I exceeds Imax (S4: Yes), the control unit accords a protection priority over the adjustment of the duty ratio and stops supplying power to the motor (S5). If current I does not exceed Imax (S4: No), the duty ratio is decreased (S7). When current I becomes lower than I2 (S8: Yes), the control unit increases the duty ratio (S10).
    Type: Application
    Filed: October 23, 2013
    Publication date: December 3, 2015
    Inventors: Nobuhito HOSOKAWA, Naoki TADOKORO
  • Publication number: 20150231771
    Abstract: A power tool includes a housing, a motor, a hammer, an anvil, a detecting unit, and a controller. The motor is accommodated in the housing. The hammer is configured to be rotated by the motor in a rotational direction about a rotational axis extending in an axial direction. The anvil is configured to be rotated upon being struck by the hammer. The detecting unit is configured to detect an impact generated in the rotational direction and the axial direction. The controller is configured to control the motor based on a detection result of the detecting unit.
    Type: Application
    Filed: July 19, 2013
    Publication date: August 20, 2015
    Inventors: Hironori Sakai, Naoki Tadokoro
  • Publication number: 20150190908
    Abstract: A rotational impact tool including: a motor; a spindle; a hammer; a first resilient member; and an anvil. The motor generates a drive force. The spindle rotates in a rotating direction upon transmission of the drive force from the motor. The spindle has an axis extending in an axial direction that includes a first direction and a second direction opposite to the first direction. The hammer moves in the rotational direction and in the axial direction relative to the spindle to generate a rotational impact force. The first resilient member urges the hammer in the first direction. The anvil transmits the rotational impact force to an end bit. The rotational impact tool further includes a second resilient member. The second resilient member is disposed at a position radially outward of the first resilient member and is configured to abut the hammer when the hammer moves in the second direction.
    Type: Application
    Filed: June 3, 2013
    Publication date: July 9, 2015
    Applicant: Hitachi Koki Co.,Ltd.
    Inventors: Naoki Tadokoro, Hironori Sakai
  • Publication number: 20150047866
    Abstract: An electric tool in which a pulsating input voltage is configured to be supplied to a drive circuit of a motor, the electric tool including: a rotation speed detection unit configured to detect a rotation speed of the motor, characterized in that the electric tool further includes: a control part configured to vary a determining value for determining whether the rotation speed of the motor satisfies a predetermined condition or not, so as to be synchronous with a pulsation cycle of the input voltage supplied to the drive circuit.
    Type: Application
    Filed: March 29, 2013
    Publication date: February 19, 2015
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Hironori Sakai, Naoki Tadokoro, Kazutaka Iwata
  • Patent number: D878886
    Type: Grant
    Filed: November 14, 2018
    Date of Patent: March 24, 2020
    Assignee: Koki Holdings Co., Ltd.
    Inventors: Shingo Kosugi, Shuji Takeda, Naoki Tadokoro