Browse Prior Art Database

Linear Actuator Bearing with Large Free Angle

IP.com Disclosure Number: IPCOM000106538D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 4 page(s) / 69K

Publishing Venue

IBM

Related People

Scheffel, JN: AUTHOR

Abstract

Disclosed is a ball bearing concept which has the potential to reduce wear and misalignment caused by bearing exceeding the free angle in a disk drive linear actuator.

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This is the abbreviated version, containing approximately 66% of the total text.

Linear Actuator Bearing with Large Free Angle

      Disclosed is a ball bearing concept which has the potential to
reduce wear and misalignment caused by bearing exceeding the free
angle in a disk drive linear actuator.

      Linear actuators in disk drives traditionally are guided by
ball bearings rolling on flat or round rails.  Due to tolerances, the
bearing position on the rails may not be precise.  This lack of
precision leads to a phenomenon known as "exceeding the free angle."
The free angle of a bearing is defined as the angle to which the
outer ring may be twisted with respect to the inner ring before the
balls make contact with the raceway (Fig. 1).

      There are several potential performance problems which could
result from exceeding the free angle.  These include increased wear
at the rail/outer ring interface, increased internal wear, increased
actuator friction due to bearing torque, unpredictable actuator
dynamics, and increased TMR (Track Mis-Registration) in the disk
drive.

      There are two standard methods to increase the free angle of a
deep groove ball bearing.  One is to increase the radial clearance,
but this will lead to increased bearing runout under a pure radial
load.  This causes increased TMR.  The other is to increase the
radius of the raceway profile, but this can lead to increased
ball/raceway wear due to higher contact stresses.

      The bearing concept disclosed here seeks to solve these
problems by a cust...