Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Osamu Beppu

Yoshihiro Moribe

Mikio Takahashi

Shigeo Nakamura

Kouki Uefune

Kenji Mori

Takako Hayakawa

Takashi Yoshida

Kenji Suzuki

Hideaki Amano

Tomoaki Inoue

Masaaki Nakano

Kiyotake Kumazawa

Kazuyoshi Hanada

Takashi Kohno

Akira Chuma

Akio Takatsuka

Masahiro Mitamura

Hideo Maekawa

Yasuo Yamamoto

Toshihiro Moribe

Youjiro Tezuka

Noriaki Minamide

Takaaki Abo

A magnetic disk apparatus capable of reducing deformation of a magnetic disk is disclosed. The magnetic disk apparatus comprises a magnetic disk on which data is recorded while the disk is driven, a hub around which the magnetic disk is supported from an under side of the magnetic disk, and a clamp in contact with the other side of the magnetic disk and fixing the magnetic disk. An O-ring is interposed between a flange formed at an outer circumference of the hub and the magnetic disk, and a spacer is interposed between the magnetic disk and the O-ring. Thus an upper surface of the hub is in contact with an under surface of the clamp and defines a vertical position of the magnetic disk.

Magnetic disk apparatus

A control device for preventing abrasion inside bearings in an information recording and reproducing device mounted on an automobile and preventing degradation in rotational accuracy, the information recording and reproducing device including disk media holding information, heads for recording or reproducing information from the disk media, a carriage for turning to position the heads on surfaces of the disk, a bearing part permitting the carriage to turn, a spindle motor for rotatingly driving the disk media, and a bearing part of the spindle motor, the control device comprising a detecting unit for detecting a vehicle operating manner, which is carried out before vehicular vibrations are caused, and a control unit for starting rotation and/or starting swings the bearing part of the spindle motor and/or the bearing part of the carriage on the basis of a signal from the detecting unit.

Controller for information recording and reproducing device and control method for the information recording and reproducing device

The motor drive method is for a magnetic disk drive apparatus having a magnetic disk as an information recording medium, a magnetic head for recording/reproducing information to/from the magnetic disk, and a motor for driving the magnetic disk, the motor having a connection point connecting middle points in a multi-phase Y-connection and capable of realizing a unipolar drive method for successively exciting phases and a bipolar drive method for simultaneously exciting two adjacent phases, wherein the unipolar drive method is selected when the temperature in the magnetic disk drive apparatus is lower than a predetermined temperature and the bipolar drive method is selected when the temperature exceeds the predetermined temperature. The motor stationary rotation is assured by selecting the unipolar drive method or the bipolar drive method.

Motor control method for magnetic disk drive

A rotor magnet is attached to the inner peripheral portion of a hub to attach a magnetic disk or the like and a stator is provided in the outer peripheral portion of a bearing housing so as to face the rotor magnet, thereby forming a rotating mechanism. A magnetic pre-load mechanism is provided and a spindle is pressed to one side of a radial bearing, thereby stabilizing the rotation.

Spindle unit having pre-load mechanism

A motor for a disc drive unit is spatially separated from an enclosure housing the magnetic disks and read-write heads. The disks are mounted on a hub that is fixed to a shaft extending through the hub, having bearings at either end of the shaft. One end of the shaft extends outside of the enclosure, the rotor of the motor is fixed to this end of the shaft and is concentric therewith. The rotor has a rotor housing that is cup-shaped, with an opening facing away from the interior of the enclosure. Inwardly of the rotor housing is a stator mounted on a supporting member. The supporting member is detachably mounted to the enclosure for easy access to the stator. Further, a circuit board having control elements for the motor, including a Hall element mounted thereon, is provided on the supporting member for easy access to the circuit board. Each of the coils of the stator is divided into windings, and the controller for the motor switches the number of windings used so that more of the windings are used for each coil during start-up than during the running condition, when less work is needed.

Magnetic disk enclosure with detachable stator

A disk drive housing structure has a rotating disk for recording information and a transducer adapted to write and read information on and from the disk. The structure further includes a positioning system having at least an arm to which the transducer is fixed and which is adapted to selectively position the transducer along the radial direction of the disk transducer by turning the arm. The structure also includes a member on which the disk, transducer and positioning system are mounted, wherein the mounting member includes a first housing which supports thereon both ends of a rotary shaft of the recording medium and both ends of a rotary shaft of the positioning system, and which has a first aperture part. The first housing further includes a second aperture part through which the disk and the rotary shaft supporting the disk are inserted and to which a supporting member for the rotary shaft of the recording medium is fixed.

Disk drive housing structure

A method of adjusting the position of a magnetic head in a magnetic head positioning mechanism positions the magnetic head at a target track on a magnetic disk. Since a floppy disk system is so designed as to make a floppy disk replaceable, it is necessary to adjust accurately the position of the magnetic head from the position of a spindle. According to the present invention, the position of the magnetic head is adjusted by the method wherein the displacement of an amount of deviation from a prescribed track in the magnetic head positioning mechanism is calculated beforehand, the amount of deviation is sampled subsequently by moving the magnetic head, this sampled amount of deviation is compared with the aforesaid calculated displacement to know the maximum and minimum values of the amounts of deviation on the track of movement of the magnetic head, and the adjustment is implemented on the basis of these values.

Method for adjustably positioning a transducer for a disc drive

A method and apparatus for moving a moving member of a positioning mechanism to a target position by means of a stepper motor as a driver. The method and apparatus alleviate the positioning error attributable to the hysteresis of the stepper motor, which is inherent in stepper motor drive systems, by controlling the oscillation damping condition when the stepper motor has entered a damped oscillation phase in the vicinity to the target positon. The damping condition is controlled by varying the solid friction factor of the mechanism or the drawback torque constant of the stepper motor.

Positioning method and apparatus therefor

A magnetic disc head positioning system using a stepper motor eliminates positioning errors due to different approach directions and distances to a target track position through a drive control of temporarily stopping the head at a position immediately preceding or following the target track depending on the approach direction and, thereafter, moving the head from this position to the target track with a constant transient response. The head is brought to the temporary stop position by utilizing the overshooting response of the stepper motor so as to minimize the positioning time.

Growing community of inventors

Oiso, Japan

Osamu Beppu