Browse Prior Art Database

Prevention of Spindle Bearing Failures in High Performance Disk Drives

IP.com Disclosure Number: IPCOM000115067D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 4 page(s) / 97K

Publishing Venue

IBM

Related People

Boutaghou, ZE: AUTHOR [+3]

Abstract

Disclosed is a method for preventing the ball bearing temperature of a high performance disk drive to rise above a preset value in order to extend the life of the ball bearings and to record the cumulative time the bearings have spent above the maximum warranted temperature.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Prevention of Spindle Bearing Failures in High Performance Disk Drives

      Disclosed is a method for preventing the ball bearing
temperature of a high performance disk drive to rise above a preset
value in order to extend the life of the ball bearings and to record
the cumulative time the bearings have spent above the maximum
warranted temperature.

      Another potential problem the disk drive industry will be
facing will be in the area of failure analysis.  How can we determine
whether the disk drive bearings have been exposed to temperatures
substantially higher than spec.  temperature and for how long?  This
becomes a disk drive warranty issue.

This disclosure attempts to propose a solution to:
  o  Reduce the temperature of the spindle ball bearings to specified
      temperature
  o  Record cumulative time the spindle ball bearings have spent
above
      specified temperature

      The Temperature Control Algorithm - The algorithm shown in
Figs. 1 and 2 shows the essence of the proposed concept.  A brief
explanation of the concept is attempted here.  First, when the file
is started, the speed of the file SpeedFlag is set to maximum speed
and a global variable EXECUTE is set to TRUE.  If during the
operation, the temperature sensor indicates that the operating
temperature "Oper Temp" exceeds the maximum allowable temperature
"Spec Temp", three scenarios are encountered.  First, the speed of
the spindle is decreased by preferably an increment (i.e., 5%) until
a steady state temperature is reached for a specific duration "Spec
Time".  Second, if this speed reduction is not enough, then
additional "latency" is added by lowering the actuator duty cycle.
Third, if the reduced speed falls below a minimum speed "Speed Limit"
and the lowest allowable duty cycle, then a major heating problem is
encountered by the file and the proposed methods will not be
sufficient to correct the problem.  In this case, the operator will
be notified and reminded abo...