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Browse Prior Art Database

Method for Spindle Balancing using Eccentric Spring Washers

IP.com Disclosure Number: IPCOM000117852D
Original Publication Date: 1996-Jun-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Kriehn, B: AUTHOR [+2]

Abstract

Use a one or more thin spring-steel washers or clips with a mass eccentricity to balance a motor-disk assembly in a computer disk drive.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 85% of the total text.

Method for Spindle Balancing using Eccentric Spring Washers

      Use a one or more thin spring-steel washers or clips with a
mass eccentricity to balance a motor-disk assembly in a computer disk
drive.

      The mass eccentricity of the ring can be achieved by cutting
away part of the circumference.  Alternately, the outer diameter
could be eccentric to the inner diameter.  In addition there is a
radial cut to allow the ring to be elastically expanded, with some
tooling holes to allow the washer to be expanded for installation.
The washer would be similar to a spring retaining clip.

      Below the flange of the motor there may be a circular groove
machined in the back-iron.  The eccentric washer is sized so that it
fits in the groove with sufficient radial force to prevent slipping.
This is shown in Fig. 1.  By measuring the imbalance of the clamped
disk stack, the eccentric washer can be oriented to compensate for
the imbalance of the stack.  For different levels of imbalance
different clips can be designed.

      The implementation described above corrects for a single plane
imbalance.  For a two plane imbalance a set of spring washers is
required at the top of the motor.  These could go either above the
clamp, or on an inner diameter above the bearing.

The current invention has the following advantages:
  1.  No adhesive required
  2.  Circular symmetry of the motor is maintained.  This reduces
       component cost and disk curvatu...