Browse Prior Art Database

DASD Spindle Airflow Bypass

IP.com Disclosure Number: IPCOM000119659D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Brewer, GW: AUTHOR [+4]

Abstract

A fan is added to the spindle of the motor-hub of a disk file to stall air flow through the motor bearings which would otherwise carry particle contamination from the bearings.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 74% of the total text.

DASD Spindle Airflow Bypass

      A fan is added to the spindle of the motor-hub of a
disk file to stall air flow through the motor bearings which would
otherwise carry particle contamination from the bearings.

      A hard-disk file operates in an enclosure in which the air is
continuously recycled through an appropriately positioned particle
filter.  Air flow is driven by the rotating data disks 1 which are
powered via spindle 2 from a two-bearing 4 electric motor 3 housed in
a central hub 5 located inside the enclosure.  Because the motor 3 is
placed inside the enclosure, particles and lubricant aerosols
released by the bearings 4 of the motor spindle 2 can enter the air
flow and deposit themselves on the disk surfaces 1.

      The reason for migration of contaminants from bearings into the
file main air flow was found to be due to a pressure differential
(HP) between the top and bottom of the hub forcing a small secondary
air leakage through the two bearings into the main air flow in a
direction from bottom to top.

      The disclosed solution is to lower the local air pressure at
the bottom bearing so that there is no differential pressure across
the two bearings through the stator of the motor.  This is achieved
by fitting a small flat fan 6 on the spindle 2.  By suitably
dimensioning the fan 6 and shaping the blades, a neutralizing
pressure is developed which greatly reduces the particle count from
bearing sources.  The shaping of the fan enab...