Patents by Inventor Katsuhiko Ohta

Katsuhiko Ohta 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: 8553348
    Abstract: A disk drive. The disk drive includes a head, an actuator, and a controller. The head accesses a disk. The actuator is configured to support the head and to move the head by action of a voice-coil motor in a substantially radial direction of the disk. The controller is also configured to perform servo control of the actuator by using servo data read out by the head. The controller includes at least one of a plurality of notch filters having a fixed center frequency inserted in a servo-control loop. The controller is configured to increase an attenuation rate by at least one of the plurality of notch filters having the fixed center frequency at a designated frequency, when a target position of the head is at a position selected from the group consisting of a position outside of a specified region and a position within the specified region.
    Type: Grant
    Filed: June 26, 2010
    Date of Patent: October 8, 2013
    Assignee: HGST Netherlands B.V.
    Inventors: Isao Yoneda, Kazuhisa Shishida, Chikako Sakagami, Katsuhiko Ohta, Kenji Okada
  • Patent number: 7986496
    Abstract: Embodiments of the present invention help to prevent data error occurrence in a hard disk drive by reducing the generation of dust caused by friction between a magnetic disk and a ramp. According to one embodiment, a hard disk drive comprises an enclosure, a motor for rotating a magnetic disk, an actuator for supporting a head slider for accessing the disk, and a ramp for loading/unloading the head slider disposed in the enclosure. The ramp comprises a tab slide formed of a resin material having a sliding characteristic to slide a tab at a tip end of the actuator at a specific velocity, and a slit on which a reinforcement made of a resin material with higher mechanical strength than the tab slide is formed.
    Type: Grant
    Filed: February 27, 2008
    Date of Patent: July 26, 2011
    Assignee: Hitachi Global Storage Technologies, Netherlands B.V.
    Inventors: Katsuhiko Ohta, Kohji Takahashi, Satoshi Matsumura
  • Publication number: 20100328810
    Abstract: A disk drive. The disk drive includes a head, an actuator, and a controller. The head accesses a disk. The actuator is configured to support the head and to move the head by action of a voice-coil motor in a substantially radial direction of the disk. The controller is also configured to perform servo control of the actuator by using servo data read out by the head. The controller includes at least one of a plurality of notch filters having a fixed center frequency inserted in a servo-control loop. The controller is configured to increase an attenuation rate by at least one of the plurality of notch filters having the fixed center frequency at a designated frequency, when a target position of the head is at a position selected from the group consisting of a position outside of a specified region and a position within the specified region.
    Type: Application
    Filed: June 26, 2010
    Publication date: December 30, 2010
    Inventors: Isao Yoneda, Kazuhisa Shishida, Chikako Sakagami, Katsuhiko Ohta, Kenji Okada
  • Patent number: 7830639
    Abstract: Embodiments in accordance with the present invention provide achieve an increase of storage capacity and thinning down of a disk drive by reducing effects from an error in an assembly position of a ramp. A data storage device according to an embodiment of the present invention includes a head, a ramp, a load beam, and an actuator. The ramp includes a portion onto which the head is retracted from a surface of a medium. The load beam includes a head support portion that supports the head and a tab disposed more on the side of a leading end than the head support portion. The tab has a leading end that slides over, while being in contact with, a sliding surface of the ramp. The actuator includes the load beam and loads and unloads the head.
    Type: Grant
    Filed: February 16, 2007
    Date of Patent: November 9, 2010
    Assignee: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Takaaki Deguchi, Mutsuro Ohta, Hiroshi Matsuda, Katsuhiko Ohta, Shinichi Kimura
  • Publication number: 20080204925
    Abstract: Embodiments of the present invention help to prevent data error occurrence in a hard disk drive by reducing the generation of dust caused by friction between a magnetic disk and a ramp. According to one embodiment, a hard disk drive comprises an enclosure, a motor for rotating a magnetic disk, an actuator for supporting a head slider for accessing the disk, and a ramp for loading/unloading the head slider disposed in the enclosure. The ramp comprises a tab slide formed of a resin material having a sliding characteristic to slide a tab at a tip end of the actuator at a specific velocity, and a slit on which a reinforcement made of a resin material with higher mechanical strength than the tab slide is formed.
    Type: Application
    Filed: February 27, 2008
    Publication date: August 28, 2008
    Inventors: Katsuhiko Ohta, Kohji Takahashi, Satoshi Matsumura
  • Publication number: 20070206330
    Abstract: Embodiments in accordance with the present invention provide achieve an increase of storage capacity and thinning down of a disk drive by reducing effects from an error in an assembly position of a ramp. A data storage device according to an embodiment of the present invention includes a head, a ramp, a load beam, and an actuator. The ramp includes a portion onto which the head is retracted from a surface of a medium. The load beam includes a head support portion that supports the head and a tab disposed more on the side of a leading end than the head support portion. The tab has a leading end that slides over, while being in contact with, a sliding surface of the ramp. The actuator includes the load beam and loads and unloads the head.
    Type: Application
    Filed: February 16, 2007
    Publication date: September 6, 2007
    Applicant: Hitachi Global Storage Technologies Netherlands B.V.
    Inventors: Takaaki Deguchi, Mutsuro Ohta, Hiroshi Matsuda, Katsuhiko Ohta, Shinichi Kimura