U.S. patent application number 10/727389 was filed with the patent office on 2004-06-17 for balancing system with adjustable eccentric rings for a disc drive assembly.
This patent application is currently assigned to Seagate Technology LLC. Invention is credited to Borning, David F., Johnson, Eric D., Koester, David D., Pfeiffer, Michael W., Spiczka, Kevin J..
Application Number | 20040111872 10/727389 |
Document ID | / |
Family ID | 31949763 |
Filed Date | 2004-06-17 |
United States Patent
Application |
20040111872 |
Kind Code |
A1 |
Pfeiffer, Michael W. ; et
al. |
June 17, 2004 |
Balancing system with adjustable eccentric rings for a disc drive
assembly
Abstract
A balancing system for a spindle assembly for compensating for
dynamic imbalance of the spindle assembly. The spindle assembly
includes a rotor rotatable about a shaft. The rotor includes a
plurality of radially concentric channels supporting adjustable
eccentric rings for dynamically balancing the spindle assembly. The
spindle assembly is balanced by adjusting the balanced of eccentric
rings assembled with the spindle assembly based upon a measured
balance of the spindle assembly and the eccentric rings.
Inventors: |
Pfeiffer, Michael W.;
(Richfield, MN) ; Koester, David D.; (Chanhassen,
MN) ; Johnson, Eric D.; (Minneapolis, MN) ;
Borning, David F.; (Burnsville, MN) ; Spiczka, Kevin
J.; (Savage, MN) |
Correspondence
Address: |
Deirdre Megley Kvale
Westman, Champlin & Kelly
Suite 1600
900 Second Avenue South
Minneapolis
MN
55402-3319
US
|
Assignee: |
Seagate Technology LLC
Scotts Valley
CA
|
Family ID: |
31949763 |
Appl. No.: |
10/727389 |
Filed: |
December 4, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10727389 |
Dec 4, 2003 |
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09721505 |
Nov 22, 2000 |
|
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6707639 |
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60193689 |
Mar 31, 2000 |
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Current U.S.
Class: |
29/603.01 ;
G9B/19.028; G9B/19.03; G9B/25.003 |
Current CPC
Class: |
G11B 19/2009 20130101;
G11B 25/043 20130101; Y10T 29/49025 20150115; G11B 19/2027
20130101; Y10T 29/49009 20150115; Y10T 29/49021 20150115 |
Class at
Publication: |
029/603.01 |
International
Class: |
G11B 005/127 |
Claims
What is claimed is:
1. A method for balancing a spindle assembly comprising steps of:
measuring an imbalance of the spindle assembly and eccentric rings
preassembled with the spindle assembly; and dynamically balancing
the spindle assembly by adjusting the eccentric rings based upon
the measured imbalance of a combined structure of the spindle
assembly and the eccentric rings.
2. The method of claim 1 wherein the imbalance of the spindle
assembly and the eccentric rings is measured with the rings in a
dynamically balanced position.
3. The method of claim 1 wherein the eccentric rings have different
diameter dimension and are supported in radially concentric
alignment.
4. The method of claim 1 wherein the step of adjusting the
eccentric rings comprises the step of: rotating a spindle of the
spindle assembly while engaging one of the eccentric rings to
adjust alignment of the one of the eccentric rings to dynamically
balance the spindle assembly.
5. The method of claim 4 wherein the spindle is rotated by a head
having at least one head pin adapted for insertion into a bore of
the spindle and comprising the steps of: inserting the at least one
head pin into the bore of the spindle to engage the spindle; and
rotating the head to rotate the spindle.
6. The method of claim 5 and further comprising the steps of:
measuring alignment of the spindle; and rotating the head prior to
inserting the at least one head pin into the bore of the spindle to
align the at least one head pin relative to the bore of the
spindle.
7. The method of claim 4 wherein the spindle assembly is coupled to
a mounting plate connected to a drive chassis and the step of
engaging the one of the eccentric rings comprises: inserting a
probe through an opening in the mounting plate to engage the one of
the eccentric rings.
8. The method of claim 4 wherein the eccentric rings include a
first eccentric ring and a second eccentric ring and comprising the
steps of: aligning a probe relative to the first eccentric ring and
engaging the first eccentric ring; rotating the spindle to adjust
the first eccentric ring; withdrawing the probe from the first
eccentric ring; aligning the probe relative to the second eccentric
ring and engaging the second eccentric ring; and rotating the
spindle to adjust the second eccentric ring.
9. The method of claim 5 and further comprising the step of:
inserting opposed spindle pins into openings on opposed ends of a
spindle portion having the spindle rotatable thereabout to support
the spindle assembly for balancing.
10. The method of claim 1 wherein the measured imbalance is
recorded on a device tag and further comprising the step of:
downloading the measured imbalance to a controller to adjust the
eccentric rings based upon the measured imbalance.
11. The method of claim 9 wherein one of said spindle pins extends
through a channel of the head and is biased in an extended position
and comprising the step of: retracting the spindle pin in the
channel of the head against the bias to engage the head with the
spindle for rotation.
12. The method of claim 7 wherein the probe is supported on a lift
coupled to an axial slide and comprising the steps of: operating
the slide to move the probe to selectively align with first and
second eccentric rings; and operating the lift to raise the probe
to engage the first and second rings and lower the probe to
disengage the first and second rings.
13. A method for balancing a spindle assembly comprising the steps
of: measuring an imbalance of a spindle assembly including an
eccentric ring; and dynamically balancing the spindle assembly by
adjusting the eccentric ring based upon the measured imbalance of
the spindle assembly and the eccentric ring.
14. The method of claim 13 wherein the step of adjusting the
eccentric ring comprises the step of: rotating a spindle of the
spindle assembly while engaging the eccentric ring to dynamically
balance the spindle assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of U.S.
application Ser. No. 09/721,505, filed Nov. 22, 2000 and entitled
"BALANCING SYSTEM WITH ADJUSTABLE ECCENTRIC RINGS FOR A DISC DRIVE
ASSEMBLY" which claims priority to U.S. Provisional Application
Serial No. 60/193,689 filed Mar. 31, 2000 and entitled "BALANCING
METHOD FOR DISC DRIVE AND MOTOR ASSEMBLY".
FIELD OF THE INVENTION
[0002] The present invention relates to a balancing system having
application for a data storage device. In particular, the present
invention relates to a balancing system for a spindle motor of a
data storage device.
BACKGROUND OF THE INVENTION
[0003] Data storage systems are known which include a plurality of
heads adapted to read or write data to a plurality of discs of a
disc stack. The plurality of discs or disc stack are supported for
co-rotation on a spindle assembly. The spindle assembly includes a
spindle hub rotatable about a spindle shaft. The disc stack is
supported on the spindle hub to rotate about the spindle shaft for
operation via operation of a spindle motor as is known.
[0004] Heads are supported relative to the rotating discs to read
or write data to the rotating discs. Accurate placement of the head
relative to the disc surface is important for seek commands and
track following for read-write operations. Various factors affect
placement of the heads relative to the disc surface. For example,
dynamic imbalance of the spindle assembly can affect track seek and
following Variations in the mass distribution of the spindle hub
can affect dynamic balance of the spindle assembly. The present
invention addresses these and other problems and provides
advantages and solutions not previously recognized.
SUMMARY OF THE INVENTION
[0005] The present invention relates to a balancing system
assembled with a spindle assembly for compensating for dynamic
imbalance of the spindle assembly. The spindle assembly includes a
rotor rotatable about a shaft. The rotor includes a plurality of
radially concentric channels supporting adjustable eccentric rings
for dynamically balancing the spindle assembly. The spindle
assembly is balanced by adjusting the balance of eccentric rings
assembled with the spindle assembly based upon a measured balance
of the spindle assembly and the eccentric rings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective illustration of an embodiment of a
data storage device or disc drive.
[0007] FIG. 2 is a cross-sectional view of a spindle assembly
supporting a disc stack.
[0008] FIG. 3 is a schematic illustration of an embodiment of
eccentric rings in a dynamically balanced position.
[0009] FIG. 4 is a schematic illustration similar to FIG. 3 with
the eccentric rings adjusted for balancing of a spindle
assembly.
[0010] FIG. 5 is a vector illustration of eccentric rings for
compensating for dynamic imbalance FIG. 6 is a perspective
illustration of an embodiment of a spindle assembly shown seated in
a mounting plate which is connectable to a chassis of a disc
drive.
[0011] FIG. 7 is a cross-sectional view taken along lines 7-7 of
FIG. 6.
[0012] FIG. 8 is a perspective illustration of a bottom portion of
the embodiment of FIG. 6.
[0013] FIG. 9 is an illustration of a "C" shaped ring including a
tab.
[0014] FIG. 10 is a schematic illustration of an embodiment of an
assembly for adjusting eccentric rings for dynamically balancing a
spindle assembly shown schematically.
[0015] FIG. 11 is a perspective illustration of an embodiment of a
balancing assembly supported along a conveyor for balancing spindle
assemblies of disc drives advanced along the conveyor.
[0016] FIG. 12 is a detailed perspective illustration of balancing
units supporting a head and a probe for adjusting eccentric rings
for dynamically balancing a spindle assembly.
[0017] FIG. 13 is a more detailed perspective illustration of the
balancing units shown in FIG. 11.
[0018] FIG. 14 is a flow chart of an embodiment of a process for
dynamically balancing a spindle assembly.
[0019] FIGS. 15-16 are schematic figures illustrating an embodiment
of the present invention for adjusting eccentric rings using a
rotating head and a probe.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0020] FIG. 1 is a schematic illustration of a data storage device
50 for storing digital information or data. As shown device 50
includes a chassis 52, a disc stack 54 and an actuator block 56
supporting a plurality of heads 58 (only one head shown in FIG. 1).
Disc stack 54 includes a plurality of discs 60 and for operation is
rotated as illustrated by arrow 62. A voice coil motor 64 moves
actuator block 56 as illustrated by arrow 66 to position heads 58
relative to selected data tracks on discs 60 of the disc stack 54
for read or write operations
[0021] Discs 60 of the disc stack 54 are supported on a spindle
assembly 68 for co-rotation. As shown, in FIG. 2, spindle assembly
68 includes a spindle shaft 70 and a spindle hub 72 rotationally
coupled to spindle shaft 70 via bearings 74, 76. Spindle shaft is
fixedly coupled to deck 52 and spindle hub 72 rotates about spindle
shaft 70 as illustrated by arrow 78 via operation of a spindle
motor. Spindle motor includes an energizable electromagnet 82
(illustrated diagrammatically) coupled to the spindle shaft 70 and
a permanent magnet 84 coupled to the spindle hub 72. As shown the
plurality of discs 60 are stacked on flange 86 of hub 74 and are
separated by spacers 88 to form the disc stack 54. The discs 60 are
clamped on hub 72 via clamp 90. Spindle hub 72 and clamp 90 rotate
about shaft 70 to form the rotor of the spindle assembly.
[0022] For desired operation, the weight distribution of the
spindle assembly should be dynamically balanced about a rotation
axis 92 of the spindle assembly for proper head disc alignment.
However, manufacture and assembly tolerance variations can
introduce an unbalanced mass distribution about the rotation axis
92. Variations in the mass distribution can cause the spindle
assembly to be dynamically imbalanced which can interfere with
track seeking and following.
[0023] The present invention provides a balancing system to
dynamically balance the spindle assembly. As schematically
illustrated in FIG. 3, the balancing system of the present
invention employs cooperating mass eccentric balance rings 100, 102
to balance the spindle assembly. The rings 100, 102 are coupled to
the rotor of the spindle assembly 68 as illustrated
diagrammatically and are cooperatively sized so that the rings 100,
102 have a dynamically balanced position about the rotation axis 92
as illustrated in FIG. 3.
[0024] The position of the mass eccentric rings is adjustable about
spindle or rotation axis 92 as illustrated by arrows 104, 106 to
adjust the mass distribution of the eccentric rings relative to
axis 92. Rings 100, 102 are adjusted as illustrated by arrows 104,
106 from the dynamically balanced position shown in FIG. 3 to an
imbalanced position shown in FIG. 4 to compensate for dynamic
imbalance of the spindle assembly as will be explained.
[0025] As shown in FIG. 3, ring 100 has a first diameter dimension
108 and ring 102 has a second diameter dimension 110 larger than
the first diameter dimension of ring 100. As shown, ring 100, 102
nest in radial concentric alignment to form inner and outer rings.
The nested arrangement of rings 100, 102 limits the height
requirement of the balance assembly (e.g. eccentric rings 100, 102)
and allows for easy single point access for balancing the spindle
assembly as will be described. The eccentric rings 100, 102 are
sized so that the nested rings 100, 102 are dynamically balanced in
the position shown in FIG. 3 based upon:
Mr.sub.100*r.sub.100=Mr.sub.102*r.sub.102:
[0026] where
[0027] Mr.sub.100 is the eccentric ring mass of ring 100 relative
to the rotation axis 92;
[0028] r.sub.100 is the radius of the center of mass of the ring
100 from the rotation axis 92;
[0029] Mr.sub.102 is the eccentric ring mass of ring 102 relative
to the rotation axis 92; and
[0030] r.sub.102 is the radius of the center of mass of ring 102
from the rotation axis 92.
[0031] The position of rings 100, 102 is adjusted as illustrated in
FIG. 4 to adjust eccentric mass distribution of
Mr.sub.100*r.sub.100 and Mr.sub.102 r.sub.1O.sub.2 about axis 92 to
balance the spindle assembly.
[0032] In the embodiment shown in FIGS. 3-4, rings 100, 102 are
generally "C" shaped rings having a constant mass portion formed by
the "C" shaped portion and a reduced mass portion formed by gaps
112, 114 between opposed ends 116, 118 of the "C" shaped portion to
provide an eccentric mass about axis 92. The dimension of gaps 112,
114 of rings 100, 102, respectively, having nested diameter
dimensions d.sub.100<d.sub.102 where d.sub.100 is the diameter
108 of ring 100 and d.sub.102 is the diameter 110 of ring 102, are
sized so that gap .sub.114<gap.sub.112 so that rings are
dynamically balanced when the gaps.sub.112,114 are orientated 180
degrees out of phase as shown in FIG. 3. Although the FIGS.
illustrate a particular embodiment of a nested eccentric ring
arrangement, application is not limited to the embodiment shown and
alternate nested mass eccentric ring arrangements can be
incorporated.
[0033] FIG. 5 is a vector illustration of a spindle mass imbalance
and eccentric ring mass distribution. As shown, the assembly
include a mass imbalance as illustrated by vector 115 having a
magnitude M and direction or angle .theta. 116. Rings 100, 102 are
adjusted to provide a counterbalance of similar mass in the opposed
direction as illustrated by vector 117. The magnitude m and
direction of the center of mass of rings is illustrated by ring
vectors 100-1, 102-1. Vectors 100-1, 102-1 illustrate dynamically
balanced ring vectors orientated 180 degrees out of phase so that
rings are dynamically balanced and have a net unbalance of zero.
The position of rings is adjusted to an imbalanced position
illustrated by ring vectors 100-2, 102-2 to provide a ring
imbalance counter to the mass imbalance of the assembly. The
magnitude of the imbalance of the rings 100, 102 is determined
based upon a resultant of vectors 100-2, 102-2 as follows:
cos(.gamma./2)=M/2m or .gamma.=cos .sup.-1(M/2m)*2
[0034] where:
[0035] M is the magnitude of the mass imbalance of the spindle
assembly;
[0036] m is the magnitude of the mass of the eccentric rings 100,
102;
[0037] .gamma. is the angle between the mass vectors 100-2, 102-2
of the eccentric rings 100, 102.
[0038] The orientation of the rings is determined based upon:
Ring 100=.theta.(116)+180 degrees-.gamma./2
Ring 102=.theta.(116)+180 degrees+.gamma./2
[0039] where .theta. is the angle of the spindle imbalance
vector.
[0040] FIGS. 6-7 illustrate an embodiment of a spindle assembly 130
including eccentric rings for balancing the spindle assembly as
previously described where like numbers are used to identify like
parts in the previous FIGS. The spindle assembly shown in FIG. 6 is
connected to mounting plate 132 to secure the spindle assembly to
the chassis or deck 52 of a disc drive through fastener holes 134
in mounting plate 132. As shown, shaft 70 includes threaded
countersunk bores 136, 138 on opposed ends as cooperatively
illustrated in FIG. 7. Rotating hub 72 includes a plurality of
threaded countersunk bores 140 spaced upon the circumference of the
spindle hub 72. Spindle hub 72 rotates about spindle shaft 70 as
previously explained by an electric motor including an energizable
electromagnet 142 on shaft 70 and a permanent magnet 144 on spindle
hub 72 as shown in FIG. 7 to rotate the supported disc stack for
operation In the embodiment illustrated, eccentric rings 100, 102
are adjustably supported in concentric channels 148, 150 formed in
an integral rim portion 152 on the spindle hub 72. Integral rim
portion 152 is formed at a base of the spindle hub 72 and channels
148, 150 on rim portion 152 are sized to allow adjustment of the
rings via an applied adjustment force and to limit movement of the
rings in channel absent an applied force. Channels 148, 150 are
spaced from axis 92 a distance 154, 156, respectively, to
concentrically house rings 100, 102 in a nested arrangement as
described in the previous embodiment.
[0041] Although FIG. 7 illustrates eccentric rings 100, 102 for a
single plane balance on a bottom rim portion 152, the invention is
not limited to a single plane balance on the rim portion shown in
FIG. 7. The assembly can include a two-plane dynamic balance system
having multiple axially spaced balancing assemblies including rings
100,102. For example, the assembly can include lower rings 100, 102
formed on a lower portion of the spindle or rotor and upper rings
100, 102 formed on an upper portion of the spindle or rotor and
spaced from the lower rings 100, 102. In one embodiment, upper
rings 100, 102 can be incorporated into the spindle cap 90.
[0042] Rings 100, 102 are assembled in channels 148, 150 and the
spindle assembly 130 including the assembled rings 100, 102 is
seated into a well 160 of mounting plate 132. As shown, mounting
plate 136 includes a shaft opening 162 for spindle shaft 70.
Mounting plate 132 and spindle assembly 130 are connected to the
drive chassis 52 through fastener holes 134 on the mounting plate
132. In the embodiment shown, shaft 70 is fixed to a cover (not
shown) by a threaded fastener in hole 136. Mounting plate 132
includes an access opening 166 opened to channels 148, 150 to
adjust rings 100, 102 for dynamic balancing.
[0043] In the embodiment shown, rings 100, 102 include a tab 167.
The position of rings 100, 102 is adjusted (or rotated) via a probe
(not shown) which extends through access opening 166 and engages
tabs 167 to rotate the rings 100, 102 to balance the spindle
assembly as previously explained. In the embodiment shown, ring
tabs 167 are formed by bending a "free end" of a "C" shaped ring
toward the access opening 166. FIG. 9 is a schematic illustration
of the mass distribution of "C" shaped rings including tab 167. As
shown, the tab 167 shifts the center of gravity 168 of the rings
100, 102 an angle .alpha. 168-1 from the center axis 169 of the
ring. In the illustrated embodiment, ring position is calculated as
follows to compensate for the mass of tab 167.
Ring 100=.theta.(116)+180
degrees-.gamma./2+.beta..sub.102/2-.alpha..sub.1- 00
Ring 102=.theta.(116)+180
degrees+.gamma./2+.beta..sub.102/2-.alpha..sub.1- 02
[0044] where:
[0045] .beta..sub.100,102 is the angle of the gap of rings 100, 102
as illustrated in FIG. 9; and
[0046] .alpha..sub.100, 102 is the angle 168-1 of the center of
gravity of rings 100, 102 from the center axis 169 as shown in FIG.
9
[0047] In the device shown, the imbalance of the spindle assembly
is measured with the rings preassembled in the spindle assembly in
the dynamically balanced position. This provides advantages and
flexibility over prior systems where the spindle is balanced prior
to completion of the spindle assembly. A balancing device as
schematically illustrated in FIG. 10, automatically adjusts the
position of the rings 100, 102 based upon the measured imbalance
via a rotator 170 which rotates the spindle hub or rotor 72
relative to the spindle shaft 70 while a probe 172 illustrated
schematically engages the rings 100, 102 to limit movement of rings
100, 102 so that the position of the rings is adjusted via rotation
of the spindle hub 72.
[0048] As shown in FIG. 11, rings 100, 102 can be adjusted as the
disc drive (with an assembled spindle) is conveyed along an
assembly conveyor 180. Prior to balancing operations, the alignment
of the spindle assembly is measured by a sensor 184 at a sensor
station 186. In the illustrated embodiment, sensor 184 includes a
camera which measures alignment of holes 140 on hub 72 for
alignment of the hub rotator mechanism 170 as will be described.
After alignment is measured, the disc drive is advanced from the
sensor station 186 to a balancing station 188.
[0049] Balancing station 188 includes balancing units 190, 192
supported in opposed upper and lower relation. Balancing unit 190
include a rotating head 194 forming rotator 170 and balancing unit
192 includes ring probe 196 shown in FIG. 12 which extends through
access opening 166 to contact rings 100, 102. As shown in FIGS.
11-12 for balancing operations, spindle assembly 130 is supported
between upper and lower spindle pins 200, 202 coupled to upper and
lower balancing units 190, 192. Spindle pins 200, 202 extend into
opposed spindle bores 136, 138 shown in FIG. 7.
[0050] As shown, head 194 is rotationally coupled to the upper
balancing unit 190 as illustrated by arrow 206 and includes at
least one hub pin 208 sized for insertion into hole 140 of the
spindle hub 72. As shown in FIG. 13, --with drive chassis
removed--, the head 194 includes a plurality of hub pins 208
circumferentially spaced for insertion into holes 140 to engage the
spindle hub 72 for rotation. Hub blocks 209 are spaced between pins
208 as shown and restrict movement of the head if the pins 208 are
not properly aligned with the holes 140. For ring adjustment, head
194 is rotated as illustrated by arrow 206 to rotate the spindle
hub while probe 196 engages one of the rings 100, 102 to hold the
ring stationary for ring adjustment.
[0051] Upper and lower balancing units 190, 192 are movably
supported relative to conveyor 180 as illustrated by arrows 210,
212 for operation. As shown in FIG. 10, balancing unit 190 is
supported on a shuttle 212 movable along a track 214 coupled to
bracket 216. Balancing unit 190 includes a motor assembly 218 which
rotates head 194 for balancing operation. Motor assembly 218 is
coupled to a controller 220 to rotate head 194 to provide the
desired ring balance.
[0052] Lower balancing unit 192 is movably supported on shuttle
platform 222 movably supported along a track 224 on stationary
block 226 as illustrated by arrow 228 between a raised position and
a lowered position. Shuttle platform 222 supports pin 202 and a
probe assembly 230. As shown in FIGS. 11-12, probe assembly 230
includes a lift block 232 supporting the probe 196 and movable
along lift track 234 on block 236 by a pneumatic lift (or other
actuator such as an electric lift) which is operated to raise and
lower lift block 232 and probe 192. As shown in FIG. 12, block 236
is supported on slide 240 movable along track 242 to adjust the
position of probe 192 to selectively engage the inner or outer ring
100, 102.
[0053] FIG. 14 schematically illustrates an operating sequence for
adjusting rings 100, 102 for balancing operations. Upper and lower
balancing units 190, 192 are normally supported in a retracted
position with the upper unit 190 raised and the lower unit 192
lowered as illustrated in FIG. 11. As shown in block 250, head 194
is rotated to align hub pins 208 with spindle holes 140 based upon
feedback from sensor 184. Head 194 is rotated by motor 218 which is
operated by controller 220 based upon feedback from sensor 184 as
illustrated by line 251 in FIG. 11. Hub blocks 209 limit movement
of the head 194 toward the spindle hub if the pins 208 are not
aligned with holes 140
[0054] As illustrated in block 252, upper and lower balancing units
190, 192 move towards the supported drive. Upper balancing unit 190
is lowered by lowering shuttle 212 along track 214 and lower
balancing unit 192 is raised by raising shuttle platform 222 along
track 224. The balancing units 190, 192 move towards the spindle so
that opposed spindle pins 200, 202 engage opposed ends of the
spindle shaft 70. As shown in FIGS. 12-13, the balancing units 190,
192 are lowered and raised, respectively, so that the spindle pins
200, 202 elevate the assembly above conveyor 180. Thereafter, the
head 194 is lowered to abut the spindle hub and the hub pins 208
are inserted into spindle holes 140 to engage spindle hub 72 for
rotation as illustrated by block 254.
[0055] As previously explained, rings 100, 102 are engaged while
head 194 is rotated. Probe 196 is aligned with a first ring as
illustrated by block 256. Probe 196 is aligned or positioned by
adjusting the position of slide 240 along track 242 as shown in
FIG. 11. Thereafter, the aligned probe 196 is raised by lift 238 to
engage the ring as illustrated by block 258. Head is rotated so
that probe 196 engages rings and is rotated to adjust the position
of the spindle hub or rotor to perfect the desired ring adjustment
as illustrated by block 260. Upon completion, probe 196 is lowered
by lift as illustrated by block 262. The process is repeated for
each ring as illustrated by line 264. Upon completion of the ring
adjustments, balancing units 190, 192 are retracted to retract head
194 and pins 200, 202 as illustrated by block 266.
[0056] As schematically illustrated in FIG. 15, upper spindle pin
200 slideably extends through channel 270 of head 194 and is spring
biased in an extended position relative to head 194 (as shown in
FIG. 13) as schematically illustrated at 272. As previously
described, shuttles 212, 222 move balancing units 190, 192 so that
pins engage shaft 70 and the assembly is raised from the conveyor
180. Continued movement of balancing units 190, 192 compresses pin
200 against the spring bias so that pin retracts relative to face
274 of head 194 so that head 194 abuts spindle hub 72 and hub pins
208 insert into holes 140 of the spindle hub as illustrated
schematically in FIG. 15. In the embodiment shown, hub pins 208 are
spring biased in an extended position for insertion into holes 140.
Thereafter head 194 rotates while probe 196 engages rings 100, 102
as previously described.
[0057] As previously described, the rings are adjusted to
compensate for a measured imbalance of the spindle assembly. The
head 194 is programmed or controlled to rotate a specific degree to
compensate for the measured imbalance. Operation of the head 194
can be controlled based upon a measured imbalance which is recorded
on an identification tag of the disc drive, and which is read from
the tag for balancing adjustments. In the embodiment shown, the
measured imbalance is read from the tag as the disc drive is
conveyed along the conveyor 180 and is downloaded to a controller
to operate the head motor 218.
[0058] A spindle assembly including a spindle hub or rotor 72
rotatable about a spindle shaft 70. The spindle hub or rotor 72
including radially concentric channels 148, 150 having eccentric
rings 100, 102 adjustably supported therein to dynamically
balancing the spindle assembly. A balancing system to dynamically
balance the spindle assembly based upon a measured imbalance of the
spindle assembly and eccentric rings 100, 102.
[0059] It is to be understood that even though numerous
characteristics and advantages of various embodiments of the
invention have been set forth in the foregoing description,
together with details of the structure and function of various
embodiments of the invention, this disclosure is illustrative only,
and changes may be made in detail, especially in matters of
structure and arrangement of parts within the principles of the
present invention to the full extent indicated by the broad general
meaning of the terms in which the appended claims are expressed.
For example, the particular elements may vary depending on the
particular application while maintaining substantially the same
functionality without departing from the scope and spirit of the
present invention. In addition, although the preferred embodiment
described herein is directed to a spindle assembly for a magnetic
disc drive system, it will be appreciated by those skilled in the
art that the teachings of the present invention can be applied to
other systems, such as optical drive systems, without departing
from the scope and spirit of the present invention.
* * * * *