Dynamic magnetic information storage or retrieval – Fluid bearing head support – Disk record
Reexamination Certificate
2000-08-10
2003-01-21
Renner, Craig A. (Department: 2652)
Dynamic magnetic information storage or retrieval
Fluid bearing head support
Disk record
C360S235700, C360S236300
Reexamination Certificate
active
06510027
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to disc drive data storage systems and, more particularly, to a disc drive data storage system having a slider with an increased bearing stiffness.
Disc drives of the “Winchester” and optical types are well known in the industry. Such drives use rigid discs, which are coated with a magnetizable medium for storage of digital information in a plurality of circular, concentric data tracks. The discs are mounted on a spindle motor, which causes the discs to spin and the surfaces of the discs to pass under respective hydrodynamic (e.g. air) bearing disc head sliders. The sliders carry transducers, which write information to and read information from the disc surfaces.
An actuator mechanism moves the sliders from track-to-track across the surfaces of the discs under control of electronic circuitry. The actuator mechanism includes a track accessing arm and a suspension for each head gimbal assembly. The suspension includes a load beam and a gimbal. The load beam provides a load force which forces the slider toward the disc surface. The gimbal is positioned between the slider and the load beam, or is integrated in the load beam, to provide a resilient connection that allows the slider to pitch and roll while following the topography of the disc.
The slider includes a bearing surface, which faces the disc surface. As the disc rotates, the disc drags air under the slider and along the bearing surface in a direction approximately parallel to the tangential velocity of the disc. As the air passes beneath the bearing surface, air compression along the air flow path causes the air pressure between the disc and the bearing surface to increase, which creates a hydrodynamic lifting force that counteracts the load force and causes the slider fly above or in close proximity to the disc surface.
During normal operating conditions, the slider is subjected to fly height modulations. These modulations are a result of a number of excitations, including intermittent head-asperity contacts, disc roughness, high-speed seeks and operating shocks. At current head-disc spacing values, disc roughness excitations have been shown to modulate the fly height by 10 percent of the nominal fly height, while asperity contacts can modulate the fly height by up to 80 percent. Moreover, the percentage of fly height modulation continues to increase as fly heights continue to decrease. This fly height modulation can degrade recording performance and can cause further contact between the head and the disc. Given the sensitive nature of the head-disc interface, such fly height modulations should be avoided or reduced as much as possible.
A slider is desired, which dampens head-media separation modulation in response to dynamic excitations.
SUMMARY OF THE INVENTION
One aspect of the present invention relates to a disc head slider, which includes a slider body having a leading edge, a trailing edge, a slider length measured from the leading edge to the trailing edge, a central recess floor and a plurality of raised rails. Each raised rail forms a respective bearing surface. At least one of the raised rails has a recessed rail surface, which is recessed from the respective bearing surface and raised from the central recess floor. At least twenty isolated bearing pads are positioned on the recessed rail surface and together form at least part of the respective bearing surface. Each bearing pad has a pad length and a pad width, which are at least one percent of the slider length.
Another aspect of the present invention relates to a disc head slider, which includes a central recess floor and first and second rails disposed about the central recess floor. Each rail includes a leading bearing surface, a recessed rail surface and a trailing bearing surface. The recessed rail surface extends rearward from the respective leading bearing surface, is recessed from the respective leading and trailing bearing surfaces, and is raised from the central recess floor. The trailing bearing surface is formed at least in part by a plurality of isolated bearing pads positioned on the recessed rail surface. Each bearing pad includes a convergent channel, which is recessed within the bearing pad and has a leading channel end open to fluid flow from the recessed rail surface, non-divergent channel side walls and a trailing channel end closed to the fluid flow and forward of a localized region of the respective bearing pad.
Yet another aspect of the present invention relates to a disc drive assembly, which includes a disc rotatable about a central axis and a slider supported over the disc. The slider has a bearing surface with features for generating a plurality of individual pressure gradients along the bearing surface, which are adapted for dampening vibrations in the slider as the disc rotates beneath the slider about the central axis.
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IBM Technical Disclosure Bulletin, “Magnetic Disk Storage System with Structured Magnetic Head Slider”, vol. 27, No. 10A, Mar. 1995, pp. 5820-5821.
Boutaghou Zine-Eddine
Chapin Mark A.
Mundt Michael D.
Murphy James M.
Sannino Anthony P.
Renner Craig A.
Seagate Technology LLC
Westman Champlin & Kelly
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