Western Digital Technologies, Inc.

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi, Ltd.

Takehiko Eguchi

Mikio Tokuyama

Toshihiko Shimizu

Takashi Kouno

Kazuhide Ichikawa

Shigeo Nakamura

Masayuki Kurita

Toshiya Shiramatsu

Hitoshi Shindo

Isao Kobayashi

Noriyo Nishijima

Teruhiro Nakamiya

Miki Namihisa

Hajime Eguchi

Yohei Asai

Toshihisa Okazaki

Hideki Izumida

Kenji Tomida

A voice coil motor assembly (VCMA), such as for a hard disk drive, includes a low-density voice coil and a high-density coil stiffener disposed inside the coil of wire. The low-density voice coil, utilizing copper-clad aluminum or aluminum wire, is configured to increase the second coil torsion mode frequency of the VCMA, thereby bringing it closer to the second torsion mode frequency of the actuator arms. In conjunction, the high-density stiffener, utilizing steel or copper or zinc, is configured to increase the mass of the VCMA to compensate for the lower-density wire in regard to the center of mass of the VCMA about its axis of rotation. In viewing under customer box vibration conditions and in terms of position error signals (PES), a non-trivial peak in the PES spectrum due to the second coil torsion mode is largely eliminated, and the power of PES is reduced to about half.

Hard disk drive voice coil motor actuator with low-density wire coil and high-density coil stiffener

In illustrative aspects, a system comprises an actuator; a control object, controlled by the actuator; and one or more processing devices. The one or more processing devices are configured to perform positioning control of the control object via the actuator, wherein performing the positioning control comprises: generating a feedforward polydyne positioning control input; and outputting the feedforward polydyne positioning control input to the actuator.

Sampled-data polydyne feedforward position control

Various illustrative aspects are directed to a system comprising: an actuator; a control object, controlled by the actuator; and one or more processing devices, configured to perform positioning control of the control object via the actuator, wherein performing the positioning control comprises: generating a trajectory control signal for a trajectory that comprises a polydyne acceleration ramp; and outputting the trajectory control signal to the actuator.

Polydyne acceleration trajectory control

A magnetic storage device that includes a housing, including a base, a cover, and an interior cavity. The magnetic storage device also includes an actuator controller, located in the interior cavity and configured to generate an actuator command signal. The magnetic storage device further includes an actuatable component, located in the interior cavity, and an actuator, located in the interior cavity and operable to actuate the actuatable component in response to the actuator command signal. The magnetic storage device also includes a vibration sensor, located in the interior cavity and configured to detect a vibration of the cover. The magnetic storage device further includes a sensor feedforward controller, located in the interior cavity and configured to generate a gain signal, based on the vibration of the cover detected by the vibration sensor, and to modify the actuator command signal proportional to the gain signal.

Vibration sensor feedforward control for magnetic storage device

A sound-attenuation part, such as for use in a rack-mount server, is configured for insertion into an orifice of a backplane to which at least one data storage device is coupled. The sound-attenuation part may include one or more pipes extending from a mounting portion. The sound-attenuation part helps to attenuate acoustic noise, such as from a cooling fan, which might otherwise reach the data storage device, such as through airflow orifices constituent to a backplane that is positioned between the fan and the storage device, while maintaining enough airflow through the backplane for system cooling purposes. Thus, degradation of the head positioning accuracy within the storage device, caused by the forces associated with this acoustic noise, may be reduced.

Fan noise attenuation at hard disk drive in rack-mount

Embodiments disclosed herein generally relate to a hard disk drive system with improved isolation from operational vibration. More particularly, embodiments disclosed herein provide a hard disk drive system with a vibration isolation frame and flexible connection without deviation from standard form factor. The standard form factor is the form factor of the hard disk drive with the base plate, but without the isolation frame. The hard disk drive with the isolation frame has the same form factor as the hard disk drive without the isolation frame, but with the base plate. Examples of form factors that may be utilized include the form factors for 3.5 inch and 2.5 inch hard disk drives. It is to be understood that 3.5 inch and 2.5 inch form factors are simply examples. Other size form factors are contemplated as well.

Hard disk drive with a vibration isolation frame

In a magnetic, disk apparatus, flows around disks are stabilized, flow-induced vibration generated in the disks and a head positioning actuator is reduced, and the positioning accuracy of the head is improved. In a magnetic disk apparatus including plural magnetic disks which are attached to a rotating motor and stacked with a spacer in between and a static structure that surrounds outer circumferences of the magnetic disks, plural current plates supported by the static structure are inserted between a pair of the magnetic disks in a stacking direction of the magnetic disks.

Magnetic disk apparatus

In a hard disk drive, for the purpose of solving a problem that a mass of the tip of a VCM actuator increases, a primary resonance frequency lowers and a control band lowers in a case where a balance driving mechanism which damps a vibration during the driving of a microactuator is mounted, a damping unit using a displacement enlargement mechanism by resonance is disposed to obtain a sufficient damping effect with a small mass, thereby setting a resonance frequency of the damping unit to be higher than a frequency of a resonance peak of a damping object. The hard disk drive includes a micromotion actuator for micromotion displacement which drives a head-gimbal assembly, and a micromotion actuator for damping which drives the damping unit so that the micromotion displacement direction of a magnetic head and the displacement direction of a mount portion have opposite phases.

Hard disk drive including a micromotion actuator and a damping unit

Embodiments in accordance with the present invention relate to greatly decreasing vibrations of a rotary disk at a portion where vibration on the disks is to be suppressed in a vibration-suppressing mechanism for rotary disks while enabling the rotary disks to be incorporated in the shroud surface. In one embodiment, the vibration-suppressing mechanism for rotary disks comprises at least one rotary disk and a shroud surface extending along and facing the outer circumferential edges of the disk. The shroud surface is so formed as to possess a portion where a gap between the outer circumferential edge of the disk and the shroud surface becomes small near a portion where the vibration of the disk is to be suppressed.

Magnetic disk vibration-suppressing mechanism having shroud-narrowing gap

Embodiments of the invention provide a magnetic disk device capable of improving the shielding function for the magnetic head yet maintaining a form factor. In one embodiment, a magnetic disk device comprises a magnetic disk; a magnetic head for recording/reproducing information; a magnetic disk drive mechanism for moving magnetic head in the radial direction of the magnetic disk; a housing including a base and a cover having a nonmagnetic material; and a magnetic shielding member having a magnetic material. The housing has a cut-away portion corresponding to a range in which the magnetic head moves, and the magnetic shielding member is formed in a U-shape including an upper wall portion, a side wall portion and a bottom wall portion. The magnetic shielding member covers the range in which the magnetic head moves, and is disposed in the cut-away portion so as to form substantially the same surface as the surfaces of the upper wall, side wall and bottom wall of the housing.

Shielding function for magnetic head in magnetic disk device

Embodiments of the invention provide a magnetic disk device which improves the shielding function for the magnetic heads while maintaining a form factor having an inexpensive constitution. In one embodiment, a magnetic disk device comprises a rotary disk-type magnetic disk; a magnetic head for recording or reproducing information; a magnetic head support mechanism for supporting the magnetic head; a shroud having an opening in which the magnetic head support mechanism is inserted, and surrounding the outer circumference of the magnetic disk; and a housing. The housing includes a base and a cover, and accommodates the magnetic disk, the magnetic head, the magnetic head support mechanism and the shroud. The base is constituted by using a nonmagnetic material and the shroud is constituted by using a magnetic material.

Magnetic disk device with improved shielding

Embodiments of the invention make high-speed rotation of a magnetic disk, suppression of an increase in electric power consumption, and suppression in shaft falling vibration compatible together in a magnetic disk device. In one embodiment, a magnetic disk device comprises a magnetic disk that records information, and a drive unit that rotates the magnetic disk about a shaft. The drive unit comprises a rotary section that holds the magnetic disk, and a stationary section that supports the rotary section through a fluid bearing. The fluid bearing comprises a radial fluid bearing that bears a load in a direction perpendicular to an axial direction, and a thrust fluid bearing that bears a load in the axial direction. The thrust fluid bearing comprises a first thrust fluid bearing having a small diameter and a shallow clearance, and a second thrust fluid bearing positioned outside an outer periphery of a shaft and being larger in diameter and deeper in clearance than the first thrust fluid bearing.

Magnetic disk device with rotor supported by fluid bearing

In a magnetic disk apparatus, a function of shielding a magnetic head is improved while maintaining the form factor with an inexpensive structure. In one embodiment, a magnetic disk apparatus has a magnetic disk, a magnetic head that records or plays back information, a magnetic head support mechanism supporting the magnetic head, a positioning mechanism that moves the magnetic head in a radial direction of the magnetic disk to place the head in position, an enclosure made of a nonmagnetic material, and a shield member made of a magnetic material. The magnetic disk, magnetic head, magnetic head support mechanism, positioning mechanism, and shield member are housed in the enclosure. The shield member has an upper shield located above the magnetic head and extending over the range of movement of the magnetic head, a lower shield located on the opposite side of the surface where the magnetic head exists and extending over the range of movement of the magnetic head, and a connecting portion connecting an outer side end portion of the upper shield and an outer side end portion of the lower shield near the outer fringes of the magnetic disk.

Magnetic disk apparatus with shield for magnetic head

In a recording apparatus capable of reducing an airflow and disturbance of the air flow simultaneously, thereby reducing flutter vibration effectively, a cover includes first convex sections for reducing a size of a gap between a disk surface and a cover or between the disk surface arid a housing in an area outside of an area in which an arm traverses on a disk in comparison with the area in which the arm traverses, and a second convex section on a part of the first convex sections to further reduce the size of the gap, and the second convex section is provided in a range extending with a tan shape thereof in a reverse rotational direction of said disk from a position distant by 110-170&#xb0; in the reverse rotational direction from a straight line connecting the rotational shaft of said disk and the rotational shaft of said arm.

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Tokyo, Japan

Takehiko Eguchi