Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Toshihisa Okazaki

Satomitsu Imai

Mikio Tokuyama

Shozo Saegusa

Yuzo Yamaguchi

Masahiko Sega

Hayato Shimizu

Shigeo Nakamura

Shigenori Togashi

Kazuo Sakai

Masao Iwakura

Toshiaki Kobari

Masayuki Kaiho

Nobuyuki Okunaga

Kazuyoshi Hanada

Hideyuki Takagi

Masayuki Honchi

Kenji Mori

Toshiaki Tsuyoshi

Takashi Kouno

Takashi Yamaguchi

Hideaki Amano

Toshihiro Arisaka

Katsuhiro Tsuneta

Satoru Yamaura

Isao Kobayashi

Yuichi Koizumi

Takeshi Yoshida

Teruhiro Nakamiya

Gentaro Nakamura

Haruhiko Hosokawa

Akio Takatsuka

Toshio Matsushita

Tetsuji Kameoka

Shigeyuki Hanazawa

Masatoshi Horinouchi

Atsushi Hiruta

Tsutomu Naitou

Satomitsu Iami

A magnetic disc unit includes a rotating disc type magnetic disc, a head for recording and reproducing data to and from the magnetic disc, and a head support mechanism for supporting the head. The magnetic disc unit includes a shroud surrounding an outer periphery of the magnetic disc other than at least at an inserting part of a carriage arm which is linked to the magnetic head support mechanism. A gap between an end face of the outer periphery of the magnetic disc and the shroud is set in a range not less than 0.1 mm but not greater than 0.4 mm.

Magnetic disc unit with gap between magnetic disc and shroud

A magnetic disc unit includes a rotating disc type magnetic disc having an outer periphery, and a carriage arm linked to a head support mechanism for a recording/reproducing head. A base has an outer periphery and mounts the rotating disc type magnetic disc and the carriage arm, and has a side wall with an inner wall surface having an opening for inserting the carriage arm. The inner wall surface of the side wall defines a shroud surrounding the outer periphery of the magnetic disc, except at the opening in the side wall where the shroud is projected inwardly so as to decrease an opening angle of the opening in the side wall. A gap between the outer periphery of the magnetic disc and the shroud is set in a range not less than 0.1 mm but not greater than 0.6 mm.

A magnetic disk apparatus includes a plurality of magnetic disks driven to rotate by a spindle motor, arms supporting magnetic heads on the magnetic disks, an actuator for moving the arms on the magnetic disks by a voice coil motor, and a housing which surrounds the magnetic disks, the arms and the actuator. A shroud which arcuately surrounds the magnetic disks along the outer periphery thereof has an opened portion for inserting the arms is formed in a part of the housing. The shroud on an upstream side of the arms relative to airflow generated by the magnetic disks when rotating is provided with an opening having a greater width than that of a gap defined between the shroud and the outer periphery of the magnetic disks. An empty bypass channel is provided which communicates from the opening through a rear side of the voice coil motor to the downstream side of the arms.

Magnetic disk apparatus with shroud and having open space downstream of moveable arms in communication with bypass channel

A servo pattern writing method of writing a servo pattern for the positioning control of a magnetic head on a magnetic disk comprises changing the rotating speed of the magnetic disk with the magnetic head positioned at one or more proper radial positions with respect to the magnetic disk. The rotating speed of the magnetic disk is changed on the basis of the magnitude of a synchronous vibration synchronous with the rotation of the magnetic disk. Writing current for writing a servo pattern is set according to the change of the rotating speed of the magnetic disk. The STW rotating speed is changed according to the change of the radial position of the magnetic head to reduce the intensity of the vibration that is generated during a servo pattern writing operation to a value meeting a positioning level. The servo track writing operation can be achieved at a low cost.

Servo pattern writing method and magnetic disk drive for carrying out the same

In a disk device, having disksand a hubfor holding thereof, to be attached onto a shaftof a spindle motor, for rotary drive thereof, a grooveis formed on a bottom surface of a flange portionof the hub, for receiving therein. A balance weightto be received in this groovehas elasticity and an outer configuration of about 'C', and further, in a portion thereof is attached at least one (1) piece of an auxiliary weight or more, thereby achieving unbalance correction at high accuracy with an aid of the balance weight. After being attached with one (1) piece or more of the 'U' shaped auxiliary weight(s) directing it/them from an inner periphery to an outer periphery thereof, the &#x201c;C&#x201d; shaped balance weight is inserted or fitted into, while being suppressed a little bit in an inside thereof. Therefore, a disk device and the unbalance correcting method for that, can be obtained, in which spaces necessary for attaching and detaching are less, but enabling the balance correction at high accuracy.

Disk device and unbalance correcting method thereof

A magnetic disc unit having a rotating disc type magnetic disc, a head for recording and reproducing data to and from the magnetic disc, and a shroud surrounding an end surface of an outer periphery of the magnetic disc, except a part where a carriage arm is inserted, wherein a gap between the outer peripheral end surface of the magnetic disc and the shroud is set in a range which is greater than 0.1 mm but not greater than 0.6 mm.

Magnetic disc unit with range of gap between disc and shroud

A magnetic disk apparatus includes magnetic disks stacked on a rotating shaft, arms supporting magnetic heads, a rotary actuator for moving the arms, and a housing forming at least a part of an arcuate-shaped shroud which substantially surrounds a portion of side surfaces of the magnetic disks so as to define a gap between the shroud and the portion of the side surfaces of the magnetic disks. The arcuate-shaped shroud has portions delimiting an open space adjacent to another portion of the side surfaces of the magnetic disks which is located on a downstream side of the arms relative to an air flow which moves on surfaces of the magnetic disks. A bypass channel provides air flow to the disks in a region of the open space at a reduced pressure on the downstream side of the arms with respect to pressure at an upstream side of the arms.

Magnetic disk apparatus with air flow bypass channel

A magnetic disc unit which can restrain occurrence of flutter so as to countermeasure such a problem that the larger the rotational speed of discs, the higher the flutter, causing heat positioning errors, in order that the high rotational speed and high positioning accuracy are consistent with each other. Discs are surrounded along their outer peripheries by a shroud (outer wall) while a gap between end faces of the discs and the shroud is decreased to a predetermined distance, thereby to eliminate air pressure differential between opposite surfaces of each of the discs in order to reduce flutter.

Magnetic disc unit

In a magnetic disc apparatus including a plurality of magnetic discs mounted on a spindle, arms supporting magnetic heads, a rotary actuator for the arms, and a housing having an arcuate-shaped shroud, the improvement wherein gaps between the shroud and the sides of outer peripheries of the magnetic discs are larger than 0.1 mm and less than 0.6 mm. An open space is located, downstream of the arms with respect to the air flow on surfaces of the magnetic discs, the open space being devoid of the shroud. An opening is provided in the shroud, upstream of the arms with respect to the air flow and having a greater width than a width of the gaps defined between the magnetic discs and the shroud, and a bypass channel is provided which communicates between the opening and open space.

Magnetic-disc unit with gap between disc and shroud

A magnetic disk apparatus includes a magnetic disk, a magnetic head for writing data into and reading data from the magnetic disk, a carriage pivoted on a pivot bearing while holding the magnetic head at its one end, the pivot bearing being constituted by a cylindrical sleeve serving as a fixed axle, bearing units each having an outer race fitted to the inside of the sleeve, bearing balls, and an inner race, and a shaft having the outside fitted to the inner races of the bearing units, thus, change of a pre-load caused by a heat expansion difference between the shaft and sleeve is an axial direction is compensated with a change of a pre-load caused thereby the same is a radius direction. Hence, the weight of a pivotally movable portion of an actuator is reduced.

Magnetic disk apparatus

A magnetic disk apparatus arranged in a housing having a plurality of magnetic disks stacked on a rotating shaft, arms supporting thereon magnetic heads and adapted to be inserted between said magnetic disks, a rotary actuator for moving the arms, a housing forming at least a part of an arcuate-shaped shroud which substantially surrounds a portion of side surfaces of the magnetic disks so as to permit movement of the arms and which is concentric with the magnetic disks so as to define a gap between the shroud and the portion of the side surfaces of said magnetic disks. The gap defined between the outer peripheral end surfaces of the magnetic disks and the shroud is in a range of 0.1 mm to 0.6 mm.

A magnetic disk apparatus of the present invention comprises a head slider with a magnetic head mounted thereon, a disk on which information is recorded/regenerated by the magnetic head, a spindle motor, integrally structured with the disk, for rotating the disk, a suspension for elastically supporting the magnetic head slider, a carriage arm for supporting the suspension and positioning the magnetic head, and a base plate for attaching the spindle motor and the carriage arm. An out-of-plane primary natural frequency of a base plate part to which the spindle is to be attached is set to be substantially the same as that of a base plate part to which the carriage arm is to be attached. An out-of-plane primary natural frequency of the carriage arm is detached from that of the base plate part to which the carriage arm is to be attached to such an extent that no resonance occurs. An out-of-plane primary natural frequency of the disk is detached from that of the base plate part to which the disk is to be attached to such an extent that no resonance occurs.

Magnetic disk apparatus in which contact between a disk and a carriage arm by an external impact is prevented

There is disclosed a support structure for a magnet-yoke assembly which prevents the magnet-yoke assembly, when vibrated on receipt of the driving reaction of a carriage, from causing a magnetic head and a magnetic disk to vibrate and which is independent of temperature. In a magnetic disk drive having a magnetic circuit which gives a driving force to a carriage holding a magnetic head so as to position the magnetic head, the magnetic circuit comprises a driving coil attached fixedly to the carriage and a magnet-yoke assembly and the magnet-yoke assembly is supported in a housing at one point thereof so as to be able to rotate in the direction parallel to the surface of the magnetic disk. The assembly is rotatably supported by means of a bearing and the bearing is given with an initial displacement so as to increase the axial bearing rigidity thereof. A base is provided with a slip guide which allows the magnet-yoke assembly to rotate with low friction and serves to give the initial displacement to the bearing. A visco-elastic member is provided for restricting the rotation of the assembly.

Magnetic disk drive

In a magnetic disk drive having a magnetic circuit which provides a driving force to a carriage holding a magnetic head so as to position the magnetic head, the magnetic circuit includes a driving coil attached fixedly to the carriage and a magnet-yoke assembly . The magnet-yoke assembly is supported in a housing at one point thereof so as to be able to rotate in the direction parallel to the surface of the magnetic disk. The assembly is rotatably supported by means of a bearing and the bearing is provided with an initial displacement so as to increase the axial bearing rigidity thereof. A base is provided with a slip guide which allows the magnet-yoke assembly to rotate with low friction and serves to provide the initial displacement to the bearing. A visco-elastic member is provided for restricting the rotation of the assembly.

A magnetic disk device having a base and a cover; a magnetic disk recording information on a recording surface thereof facing the base or the cover; a spindle motor fixed to the base and rotating the magnetic disk; a head for recording and reproducing the information to and from the recording surface of the magnetic disk; a slider having the head mounted thereto; a first suspension supporting the slider; a head arm provided between the magnetic disk and the base or the cover and supporting the first suspension on the side of the recording surface; and a carriage fixed to the base and swinging the head arm, moving the head in a radial direction of the magnetic disk and positioning the head. The magnetic disk device also has a second suspension provided on the base side or the cover side of the head arm and having a natural frequency substantially equal to a natural frequency of the first suspension.

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Odawara, Japan

Toshihisa Okazaki