Browse Prior Art Database

Damped Datum Centers

IP.com Disclosure Number: IPCOM000104228D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Benson, GA: AUTHOR [+4]

Abstract

Disclosed is a design that utilizes a constrained layer damping added to datum centers to produce a nearly flat mechanical frequency response. This design resulted in reducing the amplitude of the repeatable and non-repeatable motion during Servo Track Write (STW) of disk drives. This design also incorporates the needed stiffness for tolerance control.

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Damped Datum Centers

      Disclosed is a design that utilizes a constrained layer damping
added to datum centers to produce a nearly flat mechanical frequency
response.  This design resulted in reducing the amplitude of the
repeatable and non-repeatable motion during Servo Track Write (STW)
of disk drives.  This design also incorporates the needed stiffness
for tolerance control.

      The mechanical frequency response of Servo-Track-Writers (STW)
and the product spindle stack is typically complex with some degree
of STW/disk pack mechanical interaction.  This interaction occurs at
or near resonant peaks yielding mechanical motion of the disk pack.
When this motion occurs the quality of the servo tracks are degraded
due to deviations from a perfect circle.

      In the past, the STW used resonant tuning to avoid the
repeatable and non-repeatable harmonics of specific product spindle
speed.  This made it very difficult for transition from product to
product because of the engineering time required and hardware changes
to tune the centers.  This invention eliminates the need for tuning
because the damping acts at all frequencies, thus eliminating sharp
resonant peaks.  This invention adds damping to the STW clamping
centers by using a constrained layered damper (see the figure).  This
stiff elastomer is located between the metal center and the metal
base in such away that the mechanical path from the disk stack to the
STW is through the elastomer.  This...