Patents by Inventor Kei KOUDA

Kei KOUDA 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: 20250253738
    Abstract: A power tool (1) includes a chuck (4) disposed at a front portion of a main body (2). A handle (3) is disposed below the main body, and a battery mounting part disposed below the handle. A brushless motor (8) is disposed inside the main body and a power-supply line is electrically connected to the battery mounting part. The brushless motor includes a tubular stator (9) and a rotor (10) disposed in the interior of the stator. The rotor includes a rotor core (67) and at least one permanent magnet (68) fixed to the rotor core. A terminal (81) electrically connects the power-supply line (80) to at least one of the coils. A sensor-circuit board (65) is disposed on a front side of the stator core and is configured to detect a rotational position of the at least one permanent magnet.
    Type: Application
    Filed: April 21, 2025
    Publication date: August 7, 2025
    Inventors: Akira NIWA, Kei KOUDA
  • Patent number: 12323008
    Abstract: An electric work machine includes a brushless motor shortened in the direction of a motor shaft and allowing the rotational balance of a rotor to be easily adjustable. The electric work machine includes a brushless motor including a stator and a rotor, and at least one motor bearing supporting the rotor in a rotatable manner. The rotor includes a magnet being cylindrical and a magnet holder being hollow cylindrical or solid cylindrical. The magnet holder has a recess recessed in an axial direction, holds the magnet with the magnet being exposed in a radial direction, and has an axial length longer than the magnet. The magnet holder is partially exposed. The at least one motor bearing is at least partially received in the recess.
    Type: Grant
    Filed: October 19, 2022
    Date of Patent: June 3, 2025
    Assignee: MAKITA CORPORATION
    Inventor: Kei Kouda
  • Publication number: 20250158499
    Abstract: An electric work machine includes a first brushless motor including a first stator and a first rotor combined with the first stator, and a controller. The first stator includes a first stator core and multiple first coils wound around multiple teeth on the stator core. The controller magnetizes the teeth to cause the first rotor to rotate about a rotation axis. In a plane orthogonal to the rotation axis, the first stator core has the same shape as a second stator core in a second stator used in a second brushless motor in another electric work machine. The first rotor can be combined with the second stator. The first rotor has a different number of poles from a second rotor used in the second brushless motor.
    Type: Application
    Filed: January 16, 2025
    Publication date: May 15, 2025
    Applicant: MAKITA CORPORATION
    Inventor: Kei KOUDA
  • Patent number: 12301087
    Abstract: A power tool includes a brushless motor having a stator and a rotor. The stator includes a stator core having teeth, first and second insulators fixed to the stator core, and coils respectively wound around the teeth, all of the coils being wound around the first and second insulators. The rotor includes a rotor core disposed in the interior of the stator, a rotary shaft fixed to the rotor core, and one or more permanent magnets fixed to the rotor core. Power supply lines are configured to respectively supply current to the coils. Fusing terminals are fixed to the first insulator members. The fusing members respectively pinch the power supply lines and are thereby respectively electrically connected to the power supply lines.
    Type: Grant
    Filed: July 28, 2023
    Date of Patent: May 13, 2025
    Assignee: MAKITA CORPORATION
    Inventors: Akira Niwa, Kei Kouda
  • Patent number: 12237738
    Abstract: An electric work machine includes a first brushless motor including a first stator and a first rotor combined with the first stator, and a controller. The first stator includes a first stator core and multiple first coils wound around multiple teeth on the stator core. The controller magnetizes the teeth to cause the first rotor to rotate about a rotation axis. In a plane orthogonal to the rotation axis, the first stator core has the same shape as a second stator core in a second stator used in a second brushless motor in another electric work machine. The first rotor can be combined with the second stator. The first rotor has a different number of poles from a second rotor used in the second brushless motor.
    Type: Grant
    Filed: April 16, 2021
    Date of Patent: February 25, 2025
    Assignee: MAKITA CORPORATION
    Inventor: Kei Kouda
  • Patent number: 12237731
    Abstract: An electric work machine in one aspect of the present disclosure includes a motor, a driver, and a temperature sensor. The motor includes a stator, and a rotor. The stator includes a cylindrical body, a tooth, and a coil. The cylindrical body includes a first inner circumferential surface. The tooth is disposed to stand on the first inner circumferential surface. The coil is wound around the tooth. The coil generates a magnetic force in response to receiving an electric power. The temperature sensor is installed in/on the tooth.
    Type: Grant
    Filed: December 20, 2019
    Date of Patent: February 25, 2025
    Assignee: MAKITA CORPORATION
    Inventors: Akira Niwa, Kei Kouda
  • Publication number: 20250055360
    Abstract: An electric work machine (1) includes: a brushless motor having a stator disposed around a rotor (30); and an output part driven by the rotor. The rotor has a rotor core (31) and first and second magnetic-pole parts (34S, 34N) disposed around a circumferential direction of the rotor core. When the induced voltage of the brushless motor is given as Va, the power-supply voltage of the brushless motor is given as Vb, the rotational speed of the brushless motor is given as ?, a first induced voltage constant, which is expressed by Va/?, is given as Ea [V/krpm], a pole-pairs count, which is the number of the first magnetic-pole parts or the second magnetic-pole parts, is given as Pi, and a second induced voltage constant, which is expressed as Ea/Pi, is given as Eb [V/krpm·pole-pairs count], the motor satisfies the condition: Eb?0.025×Vb.
    Type: Application
    Filed: October 28, 2024
    Publication date: February 13, 2025
    Inventor: Kei KOUDA
  • Patent number: 12166390
    Abstract: An electric work machine (1) includes: a brushless motor having a stator disposed around a rotor (30); and an output part driven by the rotor. The rotor has a rotor core (31) and first and second magnetic-pole parts (34S, 34N) disposed around a circumferential direction of the rotor core. When the induced voltage of the brushless motor is given as Va, the power-supply voltage of the brushless motor is given as Vb, the rotational speed of the brushless motor is given as ?, a first induced voltage constant, which is expressed by Va/?, is given as Ea [V/krpm], a pole-pairs count, which is the number of the first magnetic-pole parts or the second magnetic-pole parts, is given as Pi, and a second induced voltage constant, which is expressed as Ea/Pi, is given as Eb [V/krpm·pole-pairs count], the motor satisfies the condition: Eb?0.025×Vb.
    Type: Grant
    Filed: September 6, 2022
    Date of Patent: December 10, 2024
    Assignee: MAKITA CORPORATION
    Inventor: Kei Kouda
  • Patent number: 12027958
    Abstract: An electric work machine is drivable appropriately when a brushless motor generates heat. The electric work machine includes a brushless motor including a stator, a rotor rotatable with respect to the stator, and a rotor shaft fixed to the rotor, an output unit drivable by the rotor shaft, a motor case accommodating the stator and the rotor, and a cooling fan located outside the motor case and rotatable by the rotor shaft.
    Type: Grant
    Filed: April 20, 2022
    Date of Patent: July 2, 2024
    Assignee: MAKITA CORPORATION
    Inventors: Fuminari Fujii, Kei Kouda
  • Publication number: 20240006933
    Abstract: An electric work machine includes a stator including a stator core, an insulator fixed to the stator core, and a coil mounted on the insulator, a rotor at least a part of which is disposed on an outer circumferential side of the stator, the rotor including a magnet, a stator base including a first heat dissipation fin and supporting the stator core, and an output unit driven by the rotor.
    Type: Application
    Filed: October 21, 2021
    Publication date: January 4, 2024
    Applicant: MAKITA CORPORATION
    Inventor: Kei KOUDA
  • Patent number: 11863047
    Abstract: An electric work machine, such as a lawn mower includes a motor case (22) fixed inside a main-body housing (10). A brushless motor (21) is housed inside the motor case (22) and includes a stator (23) having a stator core (40), coils (45), and upper and lower insulators (42, 43), and a rotor (24) disposed inward of the stator (23) and having a rotary shaft (25). A spindle (17) is driven by the rotary shaft (25). The motor case (22) holds the stator (23) and axially supports the rotary shaft (25) via bearings (68, 76). One or more insulating members, such as an insulating cap (67) and/or a resin layer (78), provide electrical insulation between the stator core (40) and the rotary shaft (25).
    Type: Grant
    Filed: March 28, 2023
    Date of Patent: January 2, 2024
    Assignee: MAKITA CORPORATION
    Inventors: Kei Kouda, Hideki Abe
  • Publication number: 20230369940
    Abstract: A power tool includes a brushless motor having a stator and a rotor. The stator includes a stator core having teeth, first and second insulators fixed to the stator core, and coils respectively wound around the teeth, all of the coils being wound around the first and second insulators. The rotor includes a rotor core disposed in the interior of the stator, a rotary shaft fixed to the rotor core, and one or more permanent magnets fixed to the rotor core. Power supply lines are configured to respectively supply current to the coils. Fusing terminals are fixed to the first insulator members. The fusing members respectively pinch the power supply lines and are thereby respectively electrically connected to the power supply lines.
    Type: Application
    Filed: July 28, 2023
    Publication date: November 16, 2023
    Inventors: Akira NIWA, Kei KOUDA
  • Patent number: 11757331
    Abstract: A power tool includes a brushless motor that has a stator including a tubular stator core, a rotor disposed in the tubular stator core, first and second electrically insulating members affixed to opposite ends of the stator core and a plurality of coils. A sensor-circuit board is supported by the first electrically insulating member. The first electrically insulating member is bounded by a first plane perpendicular to the rotational axis and a second plane perpendicular to the rotational axis, and the sensor-circuit board is located between the first plane and the second plane.
    Type: Grant
    Filed: November 18, 2021
    Date of Patent: September 12, 2023
    Assignee: MAKITA CORPORATION
    Inventors: Akira Niwa, Kei Kouda
  • Publication number: 20230238856
    Abstract: An electric work machine, such as a lawn mower includes a motor case (22) fixed inside a main-body housing (10). A brushless motor (21) is housed inside the motor case (22) and includes a stator (23) having a stator core (40), coils (45), and upper and lower insulators (42, 43), and a rotor (24) disposed inward of the stator (23) and having a rotary shaft (25). A spindle (17) is driven by the rotary shaft (25). The motor case (22) holds the stator (23) and axially supports the rotary shaft (25) via bearings (68, 76). One or more insulating members, such as an insulating cap (67) and/or a resin layer (78), provide electrical insulation between the stator core (40) and the rotary shaft (25).
    Type: Application
    Filed: March 28, 2023
    Publication date: July 27, 2023
    Inventors: Kei KOUDA, Hideki ABE
  • Publication number: 20230231457
    Abstract: An electric work machine includes a first brushless motor including a first stator and a first rotor combined with the first stator, and a controller. The first stator includes a first stator core and multiple first coils wound around multiple teeth on the stator core. The controller magnetizes the teeth to cause the first rotor to rotate about a rotation axis. In a plane orthogonal to the rotation axis, the first stator core has the same shape as a second stator core in a second stator used in a second brushless motor in another electric work machine. The first rotor can be combined with the second stator. The first rotor has a different number of poles from a second rotor used in the second brushless motor.
    Type: Application
    Filed: April 16, 2021
    Publication date: July 20, 2023
    Applicant: MAKITA CORPORATION
    Inventor: Kei KOUDA
  • Publication number: 20230216359
    Abstract: An electric work machine reduces a decrease in the detection accuracy of rotation of a rotor while avoiding generation of insufficient reluctance torque. The electric work machine includes a brushless motor including a rotor and a stator, and a magnetic sensor. The rotor includes a rotor core and permanent magnets. The magnetic sensor faces a first end of the rotor core to detect rotation of the rotor. The rotor core includes a first core including the first end and first slots, and a second core including second slots. The permanent magnets are received in the corresponding first and second slots. The first core includes a first portion between first slots adjacent in a circumferential direction. The second core includes a second portion between second slots adjacent in the circumferential direction. The first portion has a dimension smaller than a dimension of the second portion in the circumferential direction.
    Type: Application
    Filed: April 16, 2021
    Publication date: July 6, 2023
    Applicant: MAKITA CORPORATION
    Inventors: Junya INUZUKA, Kei KOUDA
  • Publication number: 20230179048
    Abstract: An electric work machine includes a brushless motor shortened in the direction of a motor shaft and allowing the rotational balance of a rotor to be easily adjustable. The electric work machine includes a brushless motor including a stator and a rotor, and at least one motor bearing supporting the rotor in a rotatable manner. The rotor includes a magnet being cylindrical and a magnet holder being hollow cylindrical or solid cylindrical. The magnet holder has a recess recessed in an axial direction, holds the magnet with the magnet being exposed in a radial direction, and has an axial length longer than the magnet. The magnet holder is partially exposed. The at least one motor bearing is at least partially received in the recess.
    Type: Application
    Filed: October 19, 2022
    Publication date: June 8, 2023
    Applicant: MAKITA CORPORATION
    Inventor: Kei KOUDA
  • Patent number: 11646629
    Abstract: An electric work machine, such as a lawn mower includes a motor case (22) fixed inside a main-body housing (10). A brushless motor (21) is housed inside the motor case (22) and includes a stator (23) having a stator core (40), coils (45), and upper and lower insulators (42, 43), and a rotor (24) disposed inward of the stator (23) and having a rotary shaft (25). A spindle (17) is driven by the rotary shaft (25). The motor case (22) holds the stator (23) and axially supports the rotary shaft (25) via bearings (68, 76). One or more insulating members, such as an insulating cap (67) and/or a resin layer (78), provide electrical insulation between the stator core (40) and the rotary shaft (25).
    Type: Grant
    Filed: September 6, 2022
    Date of Patent: May 9, 2023
    Assignee: MAKITA CORPORATION
    Inventors: Kei Kouda, Hideki Abe
  • Publication number: 20230076631
    Abstract: An electric work machine (1) includes: a brushless motor having a stator disposed around a rotor (30); and an output part driven by the rotor. The rotor has a rotor core (31) and first and second magnetic-pole parts (34S, 34N) disposed around a circumferential direction of the rotor core. When the induced voltage of the brushless motor is given as Va, the power-supply voltage of the brushless motor is given as Vb, the rotational speed of the brushless motor is given as ?, a first induced voltage constant, which is expressed by Va/?, is given as Ea [V/krpm], a pole-pairs count, which is the number of the first magnetic-pole parts or the second magnetic-pole parts, is given as Pi, and a second induced voltage constant, which is expressed as Ea/Pi, is given as Eb [V/krpm pole-pairs count], the motor satisfies the condition: Eb?0.025×Vb.
    Type: Application
    Filed: September 6, 2022
    Publication date: March 9, 2023
    Inventor: Kei KOUDA
  • Publication number: 20230066000
    Abstract: An electric work machine (1) includes: an inner-rotor-type brushless motor (6) having a stator (20) disposed around a rotor (30); and an output part (10), which is directly or indirectly driven by the rotor. The rotor comprises a rotor core (32) and eight permanent magnets (33) fixed to the rotor core. The stator comprises a stator core (21), one or more insulators (22, 23) fixed to the stator core, and six coils (24), which are respectively wound on teeth (21T) of the stator core via the insulator(s).
    Type: Application
    Filed: August 18, 2022
    Publication date: March 2, 2023
    Inventor: Kei KOUDA