Measuring and testing – Vibration – Sensing apparatus
Reexamination Certificate
2001-08-27
2004-02-03
Williams, Hezron (Department: 2856)
Measuring and testing
Vibration
Sensing apparatus
C369S053100
Reexamination Certificate
active
06684707
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vibration measuring method, a balance correcting method, and an information recording and/or reproducing apparatus that can be preferably used in a magnetic and electric characteristic inspection apparatus for the servo track writer, the head, the head gimbal assembly, and the head stack assembly of a hard disc drive as well as in a magnetic or electric characteristic inspection apparatus, and the like for a hard disc itself and further also can be preferably used in an inspection and manufacturing apparatus for an optical or magneto-optical recording head and an optical or magneto-optical recording disc.
2. Description of the Related Art
FIG. 1
shows an arrangement of a conventional information recording/reproducing apparatus in which a spindle motor
102
is fixed on a base
101
to drive a disc D. A head H is mounted at the extreme end of the rotating shaft of a rotary type positioning controller
103
through a head fixing jig
104
. The rotary type positioning controller
103
is supported by an X-stage
105
that is free to reciprocate on the base
101
in an X-axis direction shown by an arrow.
The distance between the center of the disc D and the center of rotation of the head H can be arbitrarily adjusted by moving the X-stage
105
. When a disc replacing job is executed, the rotary type positioning controller
103
moves in a direction where it is apart from the disc D and the spindle motor
102
.
The drive unit of the spindle motor
102
I\s composed of a motor unit
102
a
for driving the spindle motor
102
and an encoder
102
b
for detecting a rotational angle and outputting one pulse each one rotation. As shown in
FIG. 2
, the rotation of the spindle motor
102
is controlled through a spindle driver
112
in response to a command signal from a CPU
111
. The rotational shaft of the spindle motor
102
holds the disc D by a clamp
107
on a clamp base
106
and is rotatably supported by an air bearing
108
.
The drive unit of the rotary type positioning controller
103
also is composed of a motor unit
103
a
and an encoder
103
b
for detecting a rotational angle and connected to the CPU
111
through a servo controller
113
.
When information is recorded and reproduced, the X-stage
105
is moved in the X-axis direction from the position shown in
FIG. 1
to cause the rotary type positioning controller
103
to approach the spindle motor
102
, the rotary type positioning controller
103
is rotated by driving the motor unit
103
a,
the head H is positioned on an arbitrary track on the disc D, and then the spindle motor
102
starts to be driven.
When the vibration of the spindle motor
102
is measured and the balance thereof is corrected, an A/D converter
114
, an acceleration sensor
115
such as an acceleration sensor or the like and the amplifier
116
of the acceleration sensor
115
are mounted on the base
101
and connected to the CPU
111
through a PC
111
a.
As shown in
FIG. 1
, the acceleration sensor
115
is mounted in the vicinity of the spindle motor
102
.
The CPU
111
issues a command for starting the rotation of the spindle motor
102
and thereafter starts measurement by the acceleration sensor
115
. The encoder
102
b
of the spindle motor
102
generates one pulse per one rotation and determines a position of the spindle motor
102
where its rotation is unbalanced. This unbalance is corrected by a known method.
According to the above conventional technology, however, the acceleration sensor and the like must additionally be mounted on the apparatus as described above to measure vibration and to correct balance.
SUMMARY OF THE INVENTION
The present invention, which was made in view of the unsolved problems of the conventional technology, is to a provide a vibration measuring method, a balance correcting method, and information recording and/or reproducing apparatus capable of measuring the unbalance of rotating units such as a spindle motor and the like at a pinpoint accuracy and correcting it without the need of an accelerator sensor and the like.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.
REFERENCES:
patent: 5521772 (1996-05-01), Lee et al.
patent: 5636193 (1997-06-01), Ohmi
patent: 5936787 (1999-08-01), Ohmi
U.S. patent application Ser. No. 09/156,491, filed Sep. 18, 1998.
Miller Rose M.
Williams Hezron
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