Patents by Inventor Yoshihiro Ikawa

Yoshihiro Ikawa 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: 20030035362
    Abstract: A disk drive includes: a motor that rotates a disk; an auto-balancer connected to a rotating portion of the motor and changing its center of mass; a base secured to the motor and connected to an external member via a first elastic member; and a dynamic vibration absorber connected to the base via a second elastic member. If the disk whirls while rotating, a relationship between a first or second natural frequency of a first or second vibration system, including the base, first elastic member and external member or the dynamic vibration absorber, second elastic member and base, as measured parallelly to the base plane and a rotational frequency of the disk is defined so that a phase angle of 120 to 180 degrees is formed between a direction from a whirling center axis toward a center of mass of the disk and a direction from the whirling center axis toward the center of mass of the auto-balancer.
    Type: Application
    Filed: September 3, 2002
    Publication date: February 20, 2003
    Inventors: Kenji Akimaru, Teruyuki Takizawa, Yoshito Sazi, Yoshihiro Ikawa, Masahiro Inata
  • Patent number: 6181671
    Abstract: To improve the accuracy in holding a disc and to reduce unwanted vibration occurring when the disc is rotated at a high speed (the whirling of a turn table and a rotor), a spindle motor for rotating a disc comprises a turn table (3) that holds a disc (1) to rotate it, a rotor (4) that applies rotational driving force to the turn table, and a rotating shaft (5) provided on the rotation axis of the rotor, wherein the rotating shaft is fixed on the rotation axis of the turn table using a first support member, and the turn table and the rotor are supported by a second support member consisting of a filler filled in a predetermined gap (9).
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: January 30, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoshihiro Ikawa, Teruyuki Takizawa, Kenji Akimaru
  • Patent number: 5995479
    Abstract: The swing centers of guide shafts in inclination adjustment of an optical head are set to be on a plane which is perpendicular to a predetermined radial direction of an optical disk and has thereon the rotation axis of a disk motor. When the inclination adjustment of the optical head is conducted, relative gap variation between the optical head and the optical disk does not occur, and the inclination adjustment is realized within a movable range of an objective lens. The inclination angle of the optical head in a radial direction of the optical disk is adjusted by simultaneously moving upward or downward ends of two guide shafts, and the inclination angle of the optical head in a tangential direction of the optical disk can be adjusted by moving upward and downward one end of at least one of the guide shafts.
    Type: Grant
    Filed: October 1, 1997
    Date of Patent: November 30, 1999
    Assignee: Matsushita Electric Indsutrial Co., Ltd.
    Inventors: Teruyuki Takizawa, Yoshihiro Ikawa, Kenji Akimaru, Koji Miyata
  • Patent number: 5825151
    Abstract: According to the present invention, a stepping motor driving apparatus having a rotor and a stator in n (an integer equal to or larger than 2) phases for moving a moving body is provided. The stepping motor driving apparatus includes a driver for selectively supplying to the stator a first current pattern for rotating the rotor at a first pitch and a second current pattern for rotating the rotor at a second pitch different from the first pitch based on a drive switching signal. The driver switches the first current pattern and the second current pattern at a point where a torque generated by the first current pattern is equal to a torque generated by the second current pattern and supplies the first current pattern or the second current pattern to the stator.
    Type: Grant
    Filed: September 18, 1995
    Date of Patent: October 20, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yoshihiro Ikawa, Teruyuki Takizawa, Ichiro Kawamura