Browse Prior Art Database

Cost Reduction Actuator

IP.com Disclosure Number: IPCOM000111850D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Aoyagi, A: AUTHOR [+4]

Abstract

Disclosed is a designing method for rotary Actuators used in depopulated models of Hard Disk Drives (HDDs). Depopulated models of HDDs are models in which the head and disk are depopulated in order to decrease the storage capacity to meet customer requirements. The method used here does not employ a dummy head which is usually used to balance the actuator for the depopulated head(s). Another reason the dummy head is used is to equalize the inertia of the actuator and therefore keep the control circuit and software common.

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Cost Reduction Actuator

      Disclosed is a designing method for rotary Actuators used in
depopulated models of Hard Disk Drives (HDDs).  Depopulated models of
HDDs are models in which the head and disk are depopulated in order
to decrease the storage capacity to meet customer requirements.  The
method used here does not employ a dummy head which is usually used
to balance the actuator for the depopulated head(s).  Another reason
the dummy head is used is to equalize the inertia of the actuator and
therefore keep the control circuit and software common.

The method disclosed here employs a newly designed coil which has the
following characteristics:

1.  The mass of the coil is balanced to the head(s) without the dummy
    head by changing the coil thickness

2.  Coil resistance is equal to the original in order to keep the
    maximum current the same.

3.  Coil wire diameter is freely changed to meet the requirements.

4.  Voice Coil Motor (VCM) magnet is not changed, so the torque
    constant of the VCM is proportional to the number of turns.

      The mass of the coil decreases because of the decrease in the
number of heads.  Also, the number of turns decreases.  In this way,
the ratio of inertia to the torque constant may be kept equal.  The
disclosed method can effectively reduce the cost of the actuator by
the cost of the dummy head(s).  No change in the control circuit or
software is necessary.

      Fig. 1 shows an initial four-head a...