Browse Prior Art Database

Deep Enclosed Step in Air Bearing Surface

IP.com Disclosure Number: IPCOM000115817D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Zhu, LY: AUTHOR

Abstract

Disclosed is a deep enclosed step which can be placed anywhere on the air bearing surface to improve lift and reduce rail area.

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Deep Enclosed Step in Air Bearing Surface

      Disclosed is a deep enclosed step which can be placed anywhere
on the air bearing surface to improve lift and reduce rail area.

      A step is deep or shallow depending on whether it can support a
substantial pressure gradient.  A shallow step can; a deep step can
not.  For modern disk drives, a step  over 10 micrometers in depth is
considered shallow.  If a step is surrounded by barriers (e.g., rail
surfaces) and not directly connected to ambient air, it is called a
pocket.  Shallow steps enclosed by rail surfaces are disclosed by (*)
to create a "substantially ambient" pressure.  The disclosed pockets
are enclosed deep steps.

      Unlike the shallow steps of reference (1), a deep pocket
generally increases the rails load carrying capability.  It also
moves the center of pressure  up stream in the direction of air flow.
Furthermore it reduces the rail area, which may help reduce stiction.
The pocket reduces the air bearing stiffness while increasing
damping.  The pocket disclosed herein can be placed anywhere on the
air bearing surface.  However, it offers the largest advantage near
the trailing end of rails in which a front taper is either
impractical or ineffective.  Embodiments for both cases are
illustrated in Figs. 1 and 2, respectively.
  Reference
  (*) U.S. Patent 4,218,715.