Browse Prior Art Database

Tandem Preload Bearing Assembly

IP.com Disclosure Number: IPCOM000100553D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Dominguez, M: AUTHOR [+2]

Abstract

Disclosed is a preload bearing assembly for a voice coil motor (VCM) carriage. It solves a thermal track shift problem, eliminates pivot pin clearance/backlash and is self aligning at assembly.

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This is the abbreviated version, containing approximately 55% of the total text.

Tandem Preload Bearing Assembly

       Disclosed is a preload bearing assembly for a voice coil
motor (VCM) carriage.  It solves a thermal track shift problem,
eliminates pivot pin clearance/backlash and is self aligning at
assembly.

      Typically, a disk file linear carriage assembly uses 6, 7 or 8
ball bearings rolling on round or flat rails. Normally in each case 5
bearings are required to be fixed and the remainder are spring
loaded, 5 being the minimum to contain the carriage in the X, Y and Z
planes.

      The bearing system consists of 6 bearings rolling on 3 round
rails.  Each rail is mounted to the VCM which is constructed of low
carbon steel.  The 6 bearings are mounted to a light alloy carriage
at plus and minus 45 degrees.  The normal method to spring load this
system would be to have the four bearings on one side to be fixed,
one of the two bearings on the opposite side to be fixed and the one
remaining to be spring loaded at 45 degrees (Fig. 1).

      Considering the different thermal expansion coefficients of
steel and a light alloy, the alloy carrier will expand in the
direction of arrow A during file warm-up (Fig. 1).  The fixed bearing
at 45 degrees will ride up the rail by compressing the one preload
bearing which in turn raises or lowers the carriage in the direction
normal to the disk surface arrow B.  This causes a serious track
mis-registration example, if the carriage arm assembly rotates about
the fixed bearings in a down...