Patents by Inventor Kazutaka Iwata

Kazutaka Iwata 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).

  • Publication number: 20170341213
    Abstract: In order to provide an electric tool with good operability that can extend the life of and suppress breakage of a switching element for controlling energization of a brushless motor, a control unit (50), after an operation switch (5) is turned off, does not immediately turn off an inverter circuit (43) (does not set the duty of a PWM signal to 0), and instead normally operates the inverter circuit (43) with a low-duty PWM signal and waits until a rotation speed of a brushless motor (6) reaches a predetermined rotation speed or less to turn off the inverter circuit (43) (to set the duty of the PWM signal to 0).
    Type: Application
    Filed: November 27, 2015
    Publication date: November 30, 2017
    Applicant: HITACHI KOKI CO., LTD.
    Inventors: Hironori MASHIKO, Kazutaka IWATA, Yuta NOGUCHI
  • 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: 9793847
    Abstract: An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.
    Type: Grant
    Filed: March 17, 2016
    Date of Patent: October 17, 2017
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Kazutaka Iwata, Toshiaki Koizumi
  • Patent number: 9769990
    Abstract: A power tool includes: a power source (7); a tip tool (2); two switches (SW1,SW2); and a control unit (6e). The tip tool (2) is configured to be driven by the power source (7). The two switches (SW1,SW2) are configured to be turned on for activating the power source (7). The control unit (6e) is configured to control the power source (7) in accordance with on/off of the two switches (SW1,SW2), and operate if at least one of the two switches (SW1,SW2) is turned on.
    Type: Grant
    Filed: October 31, 2013
    Date of Patent: September 26, 2017
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Toshiaki Koizumi, Kazutaka Iwata, Yasutaka Shimizu
  • 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
  • Patent number: 9616558
    Abstract: According to an aspect of the present invention, there is provided an impact tool including: a motor; a hammer connected to an output portion of the motor; and an anvil to be struck by the hammer in a rotation direction and having a rotary shaft, the hammer striking the anvil in the rotation direction by driving the motor in pulses, wherein the anvil is provided in front of the hammer, wherein the hammer is driven in pulses by the motor, and wherein a rotation angle of the hammer is substantially proportional to a rotation angle of the motor.
    Type: Grant
    Filed: July 29, 2010
    Date of Patent: April 11, 2017
    Assignee: HITACHI KOKI CO., LTD.
    Inventors: Tomomasa Nishikawa, Nobuhiro Takano, Hideyuki Tanimoto, Kazutaka Iwata, Hironori Mashiko, Hayato Yamaguchi, Atsushi Nakagawa, Katsuhiro Oomori, Mizuho Nakamura, Hiroki Uchida, Saroma Nakano, Chikai Yoshimizu
  • 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: 9555537
    Abstract: A casing of a hedge clipper which is a portable tool is provided with a power source housing in which an electric motor is housed and a main handle held by a worker, and blades serving as a tip tool are provided to the casing. An operation display panel is provided on the main handle, and a driving information display unit which displays a battery remaining capacity and a rotation speed of an electric motor as a plurality of pieces of driving information is provided on the operation display panel. The selection of the information to be displayed is switched by the operation of an operation switch unit provided in the operation display panel.
    Type: Grant
    Filed: October 31, 2013
    Date of Patent: January 31, 2017
    Assignee: HITACHI KOKI CO., LTD.
    Inventors: Kazutaka Iwata, Yasutaka Shimizu, Shogo Shibata
  • Publication number: 20170012572
    Abstract: To provide a work tool capable of suppress temperature rise in a motor or a switching element. The work tool includes: a motor; a switching element switchable between an ON-state and an OFF-state, the switching element allowing a current to flow through the motor during the ON-state, the switching element prohibiting a current from flowing through the motor during the OFF-state; target rotation number setting means for setting a target rotation number of the motor; rotation number controlling means for controlling the motor such that the rotation number thereof is brought in coincidence with the target rotation number by changing an ON-duration, during which the switching element is in the ON-state, in one switching period of the switching element; and temperature detecting means for detecting at least one of a temperature of the motor and a temperature of the switching element.
    Type: Application
    Filed: January 23, 2015
    Publication date: January 12, 2017
    Inventors: Nobuhiro Takano, Yoshikazu Kawano, Toshiaki Koizumi, Hideyuki Tanimoto, Kazutaka Iwata, Shigeharu Ushiwata
  • 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
  • Patent number: 9391491
    Abstract: A power tool includes a housing, a brushless motor, and a cover member. The housing has an air intake hole and an air exhaust hole formed therein, the housing having an inner surface. The brushless motor has an outer surface disposed in the housing, a first endface near the air intake hole, and a second endface near the air exhaust hole. The cover member covers at least one of the first endface and the second endface for preventing dust from entering the brushless motor. The inner surface of the housing and outer surface of the brushless motor define a circulation path providing communication between the air intake hole and the air exhaust hole.
    Type: Grant
    Filed: September 20, 2013
    Date of Patent: July 12, 2016
    Assignee: HITACHI KOKI CO., LTD.
    Inventors: Kenichirou Yoshida, Katsuhiro Oomori, Yoshihiro Komuro, Kazutaka Iwata
  • Publication number: 20160111984
    Abstract: It is an object of the invention to provide a power tool capable of preventing damage of a switching element while maintaining drive power of a motor even when being connected to a power supply of different voltage. An impact driver 1 includes a motor 3; a rectifying circuit 23; an inverter circuit 20; and an arithmetic part 24. The rectifying circuit 23 is configured to rectify an input voltage from a commercial power supply 30. The inverter circuit 20 is configured to supply a rectified voltage output from the rectifying circuit 23 to the motor 3 as drive power. The arithmetic part 24 is configured to suppress occurrence of overcurrent where current flowing through the motor exceeds a predetermined current value.
    Type: Application
    Filed: May 16, 2014
    Publication date: April 21, 2016
    Inventors: Toshiaki Koizumi, Kazutaka Iwata
  • Patent number: 9314855
    Abstract: An electric boring tool comprises an electric motor, a switch trigger, a tip tool driven by driving force of the electric motor, a power transmission mechanism for transmitting the driving force of the electric motor to the tip tool as rotational force and/or hammer force, and a motor control unit for controlling speed of the electric motor in response to an extent of pulling of the switch trigger. The motor control unit subjects the electric motor to low speed control after the electric motor is started up, and controls the speed of the electric motor in response to the extent of pulling of the switch trigger when the load current of the electric motor is set value or greater during the low speed control.
    Type: Grant
    Filed: February 1, 2010
    Date of Patent: April 19, 2016
    Assignee: HITACHI KOKI CO., LTD.
    Inventors: Takahiro Ookubo, Kazutaka Iwata
  • Patent number: 9314908
    Abstract: According to an aspect of the present invention, there is provided an impact tool including: a motor drivable in an intermittent driving mode; a hammer connected to the motor; an anvil to be struck by the hammer to thereby rotate/strike a tip tool; and a control unit that controls a rotation of the motor by switching a driving pulse supplied to the motor in accordance with a load applied onto the tip tool.
    Type: Grant
    Filed: July 29, 2010
    Date of Patent: April 19, 2016
    Assignee: HITACHI KOKI CO., LTD.
    Inventors: Hideyuki Tanimoto, Nobuhiro Takano, Tomomasa Nishikawa, Kazutaka Iwata, Hironori Mashiko, Hayato Yamaguchi, Atsushi Nakagawa, Katsuhiro Oomori, Mizuho Nakamura, Hiroki Uchida, Saroma Nakano, Yutaka Ito
  • Publication number: 20160079887
    Abstract: An electric tool includes: a motor configured to be driven by PWM controlling a semiconductor switching element; a trigger configured to adjust startup and rotation of the motor; a changeover switch configured to switch a rotation direction of the motor between a forward rotation and a reverse rotation; a power transmission mechanism configured to rotate a tip tool by the motor, and a controller configured to control rotation of the motor. When the reverse rotation is set by the changeover switch, the controller PWM controls the semiconductor switching element at a high duty ratio after the trigger is pulled to drive the motor, and thereafter drives the motor at a state where the high duty ratio is changed to a low duty ratio.
    Type: Application
    Filed: April 25, 2014
    Publication date: March 17, 2016
    Inventors: Nobuhiro Takano, Kazutaka Iwata
  • Publication number: 20160008961
    Abstract: The purpose of the present invention is to use a motor with as high an output as possible to complete tightening operations at a high speed while limiting continuous drive output. In a power tool having a plurality of impact operation modes, the motor thereof is controlled at a 100% duty cycle so as to rotate at a high speed in the period between pulling of a trigger and starting of an impact operation (71a-71b), and the duty cycle is changed to a low duty cycle matching the appropriate operation mode after an impact by an impact mechanism is started and a predetermined stroke is performed so that the motor is driven at the low duty cycle until the trigger is returned (arrow 71c-71d). The switching of the duty cycle is performed when the current flowing to the motor exceeds a threshold (I1).
    Type: Application
    Filed: March 18, 2014
    Publication date: January 14, 2016
    Inventors: Nobuhiro Takano, Kazutaka Iwata
  • Publication number: 20150355280
    Abstract: A power tool includes: a rechargeable battery; a motor; a drive circuit; an operation unit; a battery state detection circuit; a control circuit; and an interruption circuit. The battery state detection circuit detects a battery voltage, and when the detected battery voltage is lower than or equal to a prescribed voltage, the battery state detection circuit outputs a low-voltage signal. The control means outputs a control signal to the drive circuit instructing to drive the motor when the operation unit is operated and halts the output of the control signal to the drive circuit instructing to halt driving the motor in response to the low-voltage signal. The interruption circuit outputs an interruption signal to the drive circuit in response to the low-voltage signal to thereby interrupt the drive circuit and halt driving the motor irrespective of whether or not the control signal is outputted to the drive circuit.
    Type: Application
    Filed: January 8, 2014
    Publication date: December 10, 2015
    Applicant: HITACHI KOKI CO., LTD.
    Inventor: Kazutaka Iwata
  • Publication number: 20150336249
    Abstract: An impact tool includes: a motor; a trigger; a controller configured to control driving power supplied to the motor using a semiconductor switching element according to an operation of the trigger; a striking mechanism configured to drive a tip tool continuously or intermittently by rotation force of the motor, the striking mechanism including a hammer and an anvil. The controller drives the semiconductor switching element at a high duty ratio when the trigger is manipulated. The motor is driven so that the duty ratio is lowered before a first striking of the hammer on the anvil is performed and the first striking is performed at a low duty ratio lower than the high duty ratio.
    Type: Application
    Filed: December 18, 2013
    Publication date: November 26, 2015
    Inventors: Kazutaka Iwata, Yoshihiro Komuro
  • Publication number: 20150303842
    Abstract: An impact tool includes: a motor; a controller configured to control driving power supplied to the motor using a semiconductor switching element; and a striking mechanism configured to continuously or intermittently drive a tip tool using a rotational force of the motor. The controller drives the motor by changing a PWM driving signal for driving the semiconductor switching element to mix a high-duty strike based on control of a high duty ratio and a low-duty strike based on control of a low duty ratio in one operation until a trigger is released after the trigger is pulled.
    Type: Application
    Filed: November 25, 2013
    Publication date: October 22, 2015
    Inventors: Nobuhiro TAKANO, Tomomasa NISHIKAWA, Kazutaka IWATA, Yoshihiro HOSHI
  • Publication number: 20150289451
    Abstract: A power tool includes: a power source (7); a tip tool (2); two switches (SW1,SW2); and a control unit (6e). The tip tool (2) is configured to be driven by the power source (7). The two switches (SW1,SW2) are configured to be turned on for activating the power source (7). The control unit (6e) is configured to control the power source (7) in accordance with on/off of the two switches (SW1,SW2), and operate if at least one of the two switches (SW1,SW2) is turned on.
    Type: Application
    Filed: October 31, 2013
    Publication date: October 15, 2015
    Inventors: Toshiaki Koizumi, Kazutaka Iwata, Yasutaka Shimizu