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).
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Patent number: 11780071Abstract: 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: GrantFiled: November 30, 2018Date of Patent: October 10, 2023Assignee: KOKI HOLDINGS CO., LTD.Inventors: Yasutaka Shimizu, Yoshikazu Yokoyama, Naoki Tadokoro, Ryosuke Nakano
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Patent number: 11766773Abstract: 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: GrantFiled: November 30, 2018Date of Patent: September 26, 2023Assignee: KOKI HOLDINGS CO., LTD.Inventors: Naoki Tadokoro, Ken Inui
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Publication number: 20210187722Abstract: 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: ApplicationFiled: November 30, 2018Publication date: June 24, 2021Applicant: KOKI HOLDINGS CO., LTD.Inventors: Yasutaka SHIMIZU, Yoshikazu YOKOYAMA, Naoki TADOKORO, Ryosuke NAKANO
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Publication number: 20210060754Abstract: 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: ApplicationFiled: November 30, 2018Publication date: March 4, 2021Applicant: KOKI HOLDINGS CO., LTD.Inventors: Naoki TADOKORO, Ken INUI
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Patent number: 10903775Abstract: 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: GrantFiled: October 23, 2013Date of Patent: January 26, 2021Assignee: Koki Holdings Co., Ltd.Inventors: Nobuhito Hosokawa, Naoki Tadokoro
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Patent number: 10505473Abstract: 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: GrantFiled: March 25, 2015Date of Patent: December 10, 2019Assignee: KOKI HOLDINGS CO., LTD.Inventors: Nobuhiro Takano, Kazutaka Iwata, Toshiaki Koizumi, Naoki Tadokoro, Hiroshi Haga, Shinichirou Satou
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Patent number: 9871424Abstract: 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: GrantFiled: January 31, 2014Date of Patent: January 16, 2018Assignee: HITACHI KOKI CO., LTD.Inventor: Naoki Tadokoro
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Publication number: 20170312902Abstract: 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: ApplicationFiled: October 21, 2015Publication date: November 2, 2017Applicant: Hitachi Koki Co., Ltd.Inventors: Yuta NOGUCHI, Kazutaka IWATA, Kazuhiko FUNABASHI, Tomoaki SUDO, Ken INUI, Naoki TADOKORO
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Patent number: 9768713Abstract: 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: GrantFiled: August 26, 2014Date of Patent: September 19, 2017Assignee: HITACHI KOKI CO., LTD.Inventors: Toshiaki Koizumi, Naoki Tadokoro, Kazutaka Iwata, Eiji Nakayama
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Publication number: 20170070168Abstract: 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: ApplicationFiled: March 25, 2015Publication date: March 9, 2017Inventors: Nobuhiro Takano, Kazutaka Iwata, Toshiaki Koizumi, Naoki Tadokoro, Hiroshi Haga, Shinichirou Satou
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Patent number: 9457459Abstract: 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: GrantFiled: December 27, 2011Date of Patent: October 4, 2016Assignee: Hitachi Koki Co., Ltd.Inventors: Naoki Tadokoro, Ken Miyazawa, Hajime Kikuchi, Toshiaki Koizumi
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Publication number: 20160204718Abstract: 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: ApplicationFiled: August 26, 2014Publication date: July 14, 2016Inventors: Toshiaki Koizumi, Naoki Tadokoro, Kazutaka Iwata, Eiji Nakayama
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Publication number: 20160144411Abstract: 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: ApplicationFiled: August 7, 2014Publication date: May 26, 2016Applicant: Hitachi Koki Co., Ltd.Inventors: Noriyuki HORIE, Naoki TADOKORO
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Publication number: 20150364973Abstract: 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: ApplicationFiled: January 31, 2014Publication date: December 17, 2015Inventor: Naoki Tadokoro
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Publication number: 20150352699Abstract: 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: ApplicationFiled: January 15, 2014Publication date: December 10, 2015Inventors: Hironori SAKAI, Naoki TADOKORO
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Publication number: 20150349695Abstract: 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: ApplicationFiled: October 23, 2013Publication date: December 3, 2015Inventors: Nobuhito HOSOKAWA, Naoki TADOKORO
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Publication number: 20150231771Abstract: 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: ApplicationFiled: July 19, 2013Publication date: August 20, 2015Inventors: Hironori Sakai, Naoki Tadokoro
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Publication number: 20150190908Abstract: 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: ApplicationFiled: June 3, 2013Publication date: July 9, 2015Applicant: Hitachi Koki Co.,Ltd.Inventors: Naoki Tadokoro, Hironori Sakai
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Publication number: 20150047866Abstract: 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: ApplicationFiled: March 29, 2013Publication date: February 19, 2015Applicant: HITACHI KOKI CO., LTD.Inventors: Hironori Sakai, Naoki Tadokoro, Kazutaka Iwata
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Patent number: D878886Type: GrantFiled: November 14, 2018Date of Patent: March 24, 2020Assignee: Koki Holdings Co., Ltd.Inventors: Shingo Kosugi, Shuji Takeda, Naoki Tadokoro