Patents by Inventor Tamotsu Oumi

Tamotsu Oumi 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: 9896121
    Abstract: An electric power steering apparatus that driving-controls a motor via inverters based on a current command value, and applies an assist force by the motor to a steering system, includes multi-system driving systems with the inverters for respective system-windings of the motor which is a multi-system motor, wherein respective multi-system current command value characteristics against a steering torque are applied so as to be disproportionate for left and right steering, to the respective multi-system driving systems, and an assist-control is performed in response to the individual current command value characteristics.
    Type: Grant
    Filed: December 25, 2015
    Date of Patent: February 20, 2018
    Assignee: NSK LTD.
    Inventors: Toshihiro Fukuda, Yasuhide Nomura, Tamotsu Oumi
  • Patent number: 9809246
    Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that suppresses a handle vibration (noisy sound) being caused by a handle inertia and a spring nature of a torsion bar and improves a steering feeling, without changing of the gain of the PI control. [Means for solving the problem] The present invention is an electric power steering apparatus that assist-controls a steering by driving a motor with a current command value calculated based on at least a steering torque, comprising a vibration-damping compensating section that calculates a vibration-damping compensation command value for suppressing a vibration of a handle based on a motor velocity of the motor, wherein the current command value is corrected by the vibration-damping compensation command value.
    Type: Grant
    Filed: April 7, 2014
    Date of Patent: November 7, 2017
    Assignee: NSK LTD.
    Inventors: Takahiro Tsubaki, Tamotsu Oumi
  • Publication number: 20170282966
    Abstract: An electric power steering apparatus that driving-controls a motor via inverters based on a current command value, and applies an assist force by the motor to a steering system, includes multi-system driving systems with the inverters for respective system-windings of the motor which is a multi-system motor, wherein respective multi-system current command value characteristics against a steering torque are applied so as to be disproportionate for left and right steering, to the respective multi-system driving systems, and an assist-control is performed in response to the individual current command value characteristics.
    Type: Application
    Filed: December 25, 2015
    Publication date: October 5, 2017
    Applicant: NSK LTD.
    Inventors: Toshihiro FUKUDA, Yasuhide NOMURA, Tamotsu OUMI
  • Patent number: 9557234
    Abstract: In a torque sensor of an electric power steering device, a natural and comfortable feeling to a driver (driver) is achieved by increasing the physical quantity of the torque sensor around the center of the steering wheel (neutral position). A torsion bar (3) for use in the torque sensor includes a core torsion bar (3A) and a tubular torsion bar (3B). The tubular torsion bar (3B) includes a pair of torsion tubular bar parts (3Ba, 3Bb), accommodates the core torsion bar (3A) in its inside, secures both ends of the core torsion bar (3A) in its inside, and the pair of tubular torsion parts (3Ba, 3Bb) mesh and couple each other by meshing teeth, when the core torsion bar (3A) twists a predefined rotational angle, so that a single torsion bar is configured. The elasticity of the tubular torsion bar (3B) is larger than that of the core torsion bar (3A).
    Type: Grant
    Filed: December 22, 2014
    Date of Patent: January 31, 2017
    Assignee: NSK Ltd.
    Inventors: Mikihiko Tsunoda, Tamotsu Oumi
  • Publication number: 20160282208
    Abstract: In a torque sensor of an electric power steering device, a natural and comfortable feeling to a driver (driver) is achieved by increasing the physical quantity of the torque sensor around the center of the steering wheel (neutral position). A torsion bar (3) for use in the torque sensor includes a core torsion bar (3A) and a tubular torsion bar (3B). The tubular torsion bar (3B) includes a pair of torsion tubular bar parts (3Ba, 3Bb), accommodates the core torsion bar (3A) in its inside, secures both ends of the core torsion bar (3A) in its inside, and the pair of tubular torsion parts (3Ba, 3Bb) mesh and couple each other by meshing teeth, when the core torsion bar (3A) twists a predefined rotational angle, so that a single torsion bar is configured. The elasticity of the tubular torsion bar (3B) is larger than that of the core torsion bar (3A).
    Type: Application
    Filed: December 22, 2014
    Publication date: September 29, 2016
    Inventors: Mikihiko TSUNODA, Tamotsu OUMI
  • Patent number: 9365238
    Abstract: There is provided an electric power steering device capable of detecting steering torque with high accuracy without use of a torque sensor, and capable of performing appropriate steering assistance control. An alternative torque correction value (Tc) is operated by comparing alternative torque (T0) operated based on an angle signal at normal time of the torque sensor (3) with a torque detection value (Ti) detected by the torque sensor (3), and is then stored. Then, at normal time of the torque sensor (3), the steering assistance control is performed based on the torque detection value (Ti) detected by the torque sensor (3), whereas when an abnormality happens in the torque sensor (3), the steering assistance control is performed based on corrected alternative torque (T1) obtained by correcting the alternative torque (T0) by the alternative torque correction value (Tc).
    Type: Grant
    Filed: December 16, 2014
    Date of Patent: June 14, 2016
    Assignee: NSK Ltd.
    Inventors: Mikihiko Tsunoda, Tamotsu Oumi
  • Patent number: 9352770
    Abstract: There is provided an electric power steering apparatus capable of dealing with abnormality when the abnormality happens in the torque, without being affected by an abnormal torque signal and without giving the driver a feeling of strangeness. Abnormality is detected with a double detection configuration including a main ECU clip and a sub ECU interlock. Then when abnormality is detected in steering torque detected by a torque sensor, the input of a main ECU clip is switched from the steering torque detected by the torque sensor to a torque alternative value, and the input value of the sub ECU interlock is switched from a steering assist command value subjected to limiting at the main ECU clip to zero.
    Type: Grant
    Filed: October 1, 2014
    Date of Patent: May 31, 2016
    Assignee: NSK Ltd.
    Inventors: Mikihiko Tsunoda, Mitsunori Okubo, Tamotsu Oumi
  • Publication number: 20160059885
    Abstract: [Problem] An object of the present invention is to provide an electric power steering apparatus that suppresses a handle vibration (noisy sound) being caused by a handle inertia and a spring nature of a torsion bar and improves a steering feeling, without changing of the gain of the PI control. [Means for solving the problem] The present invention is an electric power steering apparatus that assist-controls a steering by driving a motor with a current command value calculated based on at least a steering torque, comprising a vibration-damping compensating section that calculates a vibration-damping compensation command value for suppressing a vibration of a handle based on a motor velocity of the motor, wherein the current command value is corrected by the vibration-damping compensation command value.
    Type: Application
    Filed: April 7, 2014
    Publication date: March 3, 2016
    Applicant: NSK LTD.
    Inventors: Takahiro TSUBAKI, Tamotsu OUMI
  • Publication number: 20150367881
    Abstract: There is provided an electric power steering device capable of detecting steering torque with high accuracy without use of a torque sensor, and capable of performing appropriate steering assistance control. An alternative torque correction value (Tc) is operated by comparing alternative torque (T0) operated based on an angle signal at normal time of the torque sensor (3) with a torque detection value (Ti) detected by the torque sensor (3), and is then stored. Then, at normal time of the torque sensor (3), the steering assistance control is performed based on the torque detection value (Ti) detected by the torque sensor (3), whereas when an abnormality happens in the torque sensor (3), the steering assistance control is performed based on corrected alternative torque (T1) obtained by correcting the alternative torque (T0) by the alternative torque correction value (Tc).
    Type: Application
    Filed: December 16, 2014
    Publication date: December 24, 2015
    Inventors: Mikihiko TSUNODA, Tamotsu OUMI
  • Publication number: 20150274202
    Abstract: There is provided an electric power steering apparatus capable of dealing with abnormality when the abnormality happens in the torque, without being affected by an abnormal torque signal and without giving the driver a feeling of strangeness. Abnormality is detected with a double detection configuration including a main ECU clip and a sub ECU interlock. Then when abnormality is detected in steering torque detected by a torque sensor, the input of a main ECU clip is switched from the steering torque detected by the torque sensor to a torque alternative value, and the input value of the sub ECU interlock is switched from a steering assist command value subjected to limiting at the main ECU clip to zero.
    Type: Application
    Filed: October 1, 2014
    Publication date: October 1, 2015
    Applicant: NSK LTD.
    Inventors: Mikihiko Tsunoda, Mitsunori Okubo, Tamotsu Oumi
  • Patent number: 8102138
    Abstract: A motor control apparatus includes a steering column having inserted therein a steering shaft to which steering torque is transmitted, a reduction gear box coupled to the steering shaft, and an electric motor that transmits a steering assisting force to the steering shaft via a reduction mechanism in the reduction gear box. The electric motor and its control unit including a control board mounted with a control circuit, are provided side by side in the reduction gear box. A connection terminal of the electric motor is electrically connected to the control unit directly. This minimizes a connection distance between the control unit and the electric motor.
    Type: Grant
    Filed: April 11, 2007
    Date of Patent: January 24, 2012
    Assignee: NSK Ltd.
    Inventors: Takaaki Sekine, Atsushi Ooshima, Tetsuya Kodama, Seiichi Kobayashi, Yasuhiro Shimizu, Naoki Hyoudou, Shigeru Endo, Atsushi Horikoshi, Keiji Kashimoto, Tamotsu Oumi, Hideaki Kawada, Shigeo Shinohara, Takeshi Senba, Mitsuo Shimoda
  • Publication number: 20090295325
    Abstract: To provide an electric power steering apparatus in which it is possible to minimize a connection distance between a control unit and an electric motor and surely prevent electric noise from mixing between the control unit and the electric motor as well as to minimize electric resistance and minimize an electric loss by directly connecting the control unit and connection terminals of the electric motor and a torque sensor. A motor control apparatus includes a steering column 3 having inserted therein a steering shaft 2 to which steering torque is transmitted, a reduction gear box 4 coupled to the steering shaft 2, and an electric motor 5 that transmits a steering assisting force to the steering shaft 2 via a reduction mechanism in the reduction gear box 4.
    Type: Application
    Filed: April 11, 2007
    Publication date: December 3, 2009
    Applicant: NSK Ltd.
    Inventors: Takaaki Sekine, Atsushi Ooshima, Tetsuya Kodama, Seiichi Kobayashi, Yasuhiro Shimizu, Naoki Hyoudou, Shigeru Endo, Atsushi Horikoshi, Keiji Kashimoto, Tamotsu Oumi, Hideaki Kawada, Shigeo Shinohara, Takeshi Senba, Mitsuo Shimoda