Dynamic magnetic information storage or retrieval – Head mounting – Disk record
Reexamination Certificate
2001-03-08
2001-10-02
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Head mounting
Disk record
Reexamination Certificate
active
06297933
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to disk drive suspensions, and, more particularly to improvements in the use of damping material on disk drive suspension load beams to avoid environmental degradation from outgassing of the organic damping material, or from moisture absorption and contaminant attraction by the damping material.
2. Related Art
Damping material comprises various organic, visco-elastic compositions, generally polymeric in nature, that have the property of absorbing and dissipating vibrational energy and thus serve to limit increases in amplitude of vibrations experienced by disk drive suspensions. Damping materials have been placed on suspension load beams for some years, usually as a multilayer structure of the damping material, a metal backing and optionally adhesive layers to maintain the damping material in place.
SUMMARY OF THE INVENTION
Problems with use of damping materials include difficulty of accurate placement on the load beam through operator error and the need for fixturing, and environmental degradation. Environmental degradation includes outgassing from the damping material composition that may degrade adjacent components of the suspension or disk drive, and the absorption of moisture by or the attraction of ambient atmospheric contaminants to the damping materials through their substantial exposure to ambient atmosphere.
It is an object of the present invention to limit environmental degradation associated with the use of damping materials in disk drive suspensions. It is a further object to provide for the rapid and accurate placement of damping materials on load beams. Yet another object is the provision of a recess in the load beam that accurately places the damping material and also in cooperation with a metal layer of the damping structure closes access of the ambient atmosphere to the damping material and vice-versa, thus limiting environmental degradation from and to the damping material.
These and other objects of the invention to become apparent hereinafter are realized in a disk drive suspension comprising a load beam having a distal rigid portion and a damping structure comprising a visco-elastic damping material layer and a metal layer attached to the load beam distal rigid portion in load beam vibration amplitude damping relation, the load beam distal rigid portion having a preformed recess sized and shaped to locate the damping structure on the load beam distal rigid portion and receive and encapsulate within the recess at least the damping material layer.
In this and like embodiments, typically, the damping material is organic and tends to environmental degradation when exposed to the ambient atmosphere by outgassing and attracting moisture and other environmental contaminants, and the damping material is sandwiched in the recess between the load beam distal rigid portion and the metal layer in ambient atmosphere exposure limiting relation, the damping structure is circular in cross-section, the recess being circular in cross-section and close-fitting about the damping structure, the damping structure is polygonal in cross-section, the recess being closely congruent about the damping structure, the recess is etched into a proximate area of the load beam distal rigid portion, and the damping structure has a predetermined height, the recess having a depth sufficient to fully receive the damping structure damping material layer first and metal layer second, the metal layer and the load beam portion surrounding the recess acting together to limit exposure to the ambient atmosphere of the damping material.
In a preferred embodiment, the invention provides a disk drive suspension comprising a spring metal load beam having a distal rigid portion adapted to carry a slider and a damping structure comprising in stacked relation a first layer comprising an organic, visco-elastic damping material tending to environmental degradation when exposed to ambient atmosphere by outgassing and attracting moisture and other environmental contaminants and a second overlayer comprising a metal layer covering the damping material first layer, the damping structure being attached to the load beam distal rigid portion in load beam vibration amplitude damping relation, the load beam distal rigid portion having a preformed recess positioned to locate the damping structure on the load beam distal rigid portion and sized and shaped to receive fully the damping material layer first and the metal layer second within the recess, the metal layer and the load beam portion surrounding the recess fitting closely together to limit exposure to the ambient environment of the damping material layer.
In this and like embodiments, typically, the damping structure is circular in cross-section, the recess being circular in cross-section and close-fitting about the damping structure, or the damping structure is polygonal in cross-section, the recess being closely congruent about the damping structure, and the recess is etched into a proximate area of the load beam distal rigid portion.
In a particularly preferred embodiment, the invention provides a disk drive suspension comprising a spring metal load beam having a distal rigid portion adapted to carry a slider and a damping structure of predetermined height and comprising in stacked relation a first cylindrical layer comprising an organic, visco-elastic damping material tending to environmental degradation when exposed to ambient atmosphere by outgassing and attracting moisture and other environmental contaminants and equal to from 30 to 70% of the damping structure predetermined height and a second cylindrical layer of substantially the same diameter as the first layer, the second layer diameter comprising a metal layer equal to from 70 to 30% of the damping structure predetermined height and covering the damping material first layer, the damping structure being attached to the load beam distal rigid portion in load beam vibration amplitude damping relation, the load beam distal rigid portion having a preformed cylindrical recess positioned to locate the damping structure on a proximate area of the load beam distal rigid portion and sized and shaped to receive fully the damping material layer first and the metal layer second within the recess, the metal layer and the load beam portion surrounding the recess fitting closely together to limit exposure to the ambient environment of the damping material layer.
The invention further provides a method of manufacturing a disk drive suspension having damping material attached, including forming a recess in a suspension load beam, positioning a congruent damping structure relative to the load beam with the recess, and inserting a congruent damping structure comprising a first layer of damping material and a second layer of metal into the recess to a depth such that the damping material is surrounded by the recess and covered by the metal layer within the recess.
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patent: 4819094 (1989-04-01), Oberg
patent: 5187625 (1993-02-01), Blaeser et al.
patent: 5771135 (1998-06-01), Ruiz et al.
patent: 5825590 (1998-10-01), Ohwe
patent: 5936808 (1999-08-01), Huang et al.
patent: 5949617 (1999-09-01), Zhu
patent: 6212043 (2001-04-01), Nakamura et al.
patent: 1-248372 A (1989-10-01), None
patent: 3-278382 A (1991-12-01), None
Coon Warren
Khan Amanullah
Bachand Louis J.
Magnecomp Corporation
Tupper Robert S.
Watko Julie Anne
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