Title: Two-part flow conditioning apparatus for a disc drive
Abstract: A disc drive includes a base, at least one disc rotatably attached to the base, and an actuator assembly rotatably attached to base and supporting a slider and a transducer at a distal end thereof. The slider and transducer are positioned to be in transducing relation with respect to the disc. An air dam is positioned over the disc and near an arc through which the slider and transducer are rotated. The air dam is positioned so as to produce an area of high pressure substantially about an area including a portion of the arc through which the slider and transducer are rotated. Surfaces are aligned with and extend in a coplanar relationship with the disc to transfer an outwardly directed airflow away from the disc without impinging turbulent flow on or at the disc edge.
Patent Number: 6,987,640 Issued on 01/17/2006 to Tsang, et al.
| Inventors:
|
Tsang; Alan Hing-Bun (Minneapolis, MN);
Kaneko; James Eiji (Oakdale, MN);
Tadepalli; Srinivas (Eden Prairie, MN);
Welscher; Cory Bert (Belle Plaine, MN);
Narisaranukul; Narintr (Bloomington, MN);
Peterson; Blaine Thomas (Bloomington, MN);
Adams; Carl Fred (Yukon, OK)
|
| Assignee:
|
Seagate Technology LLC (Scotts Valley, CA)
|
| Appl. No.:
|
228425 |
| Filed:
|
August 27, 2002 |
| Current U.S. Class: |
360/97.02; 360/97.03; 360/254.7 |
| Current Intern'l Class: |
G11B 33/14 (20060101); G11B 25/04 (20060101); G11B 21/22 (20060101) |
| Field of Search: |
360/9702,970.1,970.3,970.4,256.1,264.4,254.4,254.3,254.5,254.6,255.2,255.3,255.4,255.5,254.7
|
References Cited [Referenced By]
U.S. Patent Documents
| 4647997 | Mar., 1987 | Westwood.
| |
| 4703379 | Oct., 1987 | Bogdanski.
| |
| 5031059 | Jul., 1991 | Yamaguchi et al.
| |
| 5036416 | Jul., 1991 | Mastache.
| |
| 5134530 | Jul., 1992 | Hall.
| |
| 5140578 | Aug., 1992 | Tohkairin.
| |
| 5274519 | Dec., 1993 | Saito et al.
| |
| 5898545 | Apr., 1999 | Schirle.
| |
| 6031690 | Feb., 2000 | Kelemen et al.
| |
| 6091570 | Jul., 2000 | Hendriks.
| |
| 6097568 | Aug., 2000 | Ekhoff.
| |
| Foreign Patent Documents |
| 0 450 184 | Dec., 1990 | EP.
| |
Primary Examiner: Renner; Craig A.
Attorney, Agent or Firm: Fellers, Snider, et al.
Parent Case Text
RELATED APPLICATIONS
This is a continuation-in-part application of the U.S. patent application Ser.
No. 09/894,668 filed Jun. 27, 2001 which is based on the provisional application
No. 60/220,722 filed Jul. 26, 2000, and is also a continuation-in-part of the U.S.
patent application Ser. No. 09/901,318 filed Jul. 9, 2001 abandon which is based
on the provisional application No. 60/235,613 filed Sep. 27, 2000 and the provisional
application No. 60/277,782 filed Mar. 21, 2001.
Claims
What is claimed is:
1. A flow conditioning apparatus for use in a disc drive comprising:
a plurality of a first extension defining a first plane; and
a plurality of a second extension pivotably connected to the first extension
for rotational movement about an axis, the second extension being rotatable in
a second plane that is substantially parallel tote first plane, wherein the first
extensions and the second extensions are interleaved along the axis.
2. The flow conditioning apparatus of claim 1 in which the second extensions
fit between the respective first extensions when the flow conditioning apparatus
is in a folded configuration, and in which the second extensions are positioned
away from the first extensions when the flow conditioning apparatus is in an operational configuration.
3. The flow conditioning apparatus of claim 2 further comprising a lock to bias
the second extensions against the first extensions such that the flow conditioning
apparatus is retained in the operational configuration.
4. The flow conditioning apparatus of claim 1 in which the second extensions
have an arcuate edge.
5. The flow conditioning apparatus of claim 1 in which the first extension includes
a proximal end and a distal end, the flow conditioning apparatus further comprising
a shroud defining a plane substantially transverse to the first plane, in which
the sbroud runs substantially from the proximal end to the distal end.
6. The flow conditioning apparatus of claim 5 in which the first extension is
wider at the distal end than at the proximal end.
7. The flow conditioning apparatus of claim 1 in which the first extension further
comprises a ramp.
8. A disc drive comprising:
a disc configured for rotation such that a fluid flow is generated by the disc
when in rotation;
an actuator adjacent the disc; and
a flow conditioning apparatus located adjacent the disc, the flow conditioning
apparatus comprising:
a first extension comprising a side aligned with the disc and opposing surfaces
extending immediately from the side in a direction away from the disc defining
a first plane disposed in a coplanar relationship with the disc; and
a second extension pivotably connected to the first extension for rotational
movement about an axis, the second extension being rotatable in a second plane
that is substantially parallel to the first plane, wherein the second extension
is downstream of the actuator with respect to the fluid flow.
9. The disc drive of claim 8 in which the second extension extends substantially
radially from an outer radial portion of the disc to an inner radial portion of
the disc.
10. The disc drive of claim 9 in which the second extension is disposed substantially
transverse to a distal end of the actuator.
11. The disc drive of claim 9 in which the second extension has an arcuate leading
edge, wherein the arcuate leading edge is disposed in proximity to a distal end
of the actuator.
12. The disc drive of claim 8 in which the first extension extends arcuately
along an outer edge of the disc in proximity to the outer edge.
13. The disc drive of claim 8 in which the first extension opposing surfaces
are substantially coextensive with respective disc surfaces.
14. The disc drive of claim 8 further comprising:
a plurality of the disc; and
a plurality of the second extension wherein, in an operational configuration,
the second extensions interleave the discs.
15. The disc drive of claim 14 further comprising a plurality of the first extension
in which, in a folded configuration, the second extensions interleave the first extensions.
16. The disc drive of claim 15 in which the second extensions fit between the
respective first extensions when the flow conditioning apparatus is in a folded
configuration, and in which the second extensions are positioned away from the
first extensions when the flow conditioning apparatus is in an operational configuration.
17. The disc drive of claim 16 further comprising a lock to bias the second extensions
against the first extensions such that the flow conditioning apparatus is retained
in the operational configuration.
18. The disc drive of claim 8 in which the first extension includes a proximal
end and a distal end, the flow conditioning apparatus further comprising a shroud
defining a plane substantially transverse to the first plane, in which the shroud
runs substantially from the proximal end to the distal end.
19. The disc drive of claim 18 in which the shroud is nearer the disc at the
proximal end than at the distal end.
20. The disc drive of claim 8 in which the first extension further comprises
a ramp adapted to receive a distal end of the actuator.
21. The disc drive of claim 8 in which the flow conditioning apparatus further
comprises a filter housing connected to the first extension.
22. A disc drive comprising:
at least one disc;
read/write devices supportable in proximity to the at least one disc; and
means for conditioning air flow around the read/write devices in which the air
flow is generated by the at least one disc in rotation.
23. The disc drive of claim 22 in which the means for conditioning air flow is
located downstream of the read/write devices with respect to the air flow.
24. The disc drive of claim 22 in which the means for conditioning air flow is
operable between an installation configuration and an operational configuration.
25. The disc drive of claim 24 in which the means for conditioning air flow occupies
a smaller volume of space when in the installation configuration than in the operational configuration.
26. A flow conditioning apparatus comprising proximally hinged first and second
extensions that arc moveable between an unfolded configuration where the extensions
are distally separated and a folded configuration where the extensions are distally
interleaved, wherein the apparatus is configured to align the first extensions
with a like number of data storage mediums in the folded configuration and to move
the second extensions to the unfolded configuration to interleave the second extensions
with the data storage mediums.
Description
FIELD OF THE INVENTION
The present invention relates generally to the field of data storage devices.
More particularly, but not by way of limitation, this invention relates to an apparatus
and method for controlling the aerodynamic excitation imparted to disc drive components
by airstreams generated by spinning discs in a disc drive.
BACKGROUND OF THE INVENTION
One key component of any computer system is a device to store data. Computer
systems have many different places where data can be stored. One common place for
storing massive amounts of data in a computer system is on a disc drive. The most
basic parts of a disc drive are an information storage disc that is rotated, an
actuator that moves a transducer to various locations over the disc, and electrical
circuitry that is used to write and read data to and from the disc. The disc drive
also includes circuitry for encoding data so that it can be successfully retrieved
and written to the disc surface. A microprocessor controls most of the operations
of the disc drive as well as passing the data back to the requesting computer and
taking data from a requesting computer for storing to the disc.
The transducer is typically placed on a small ceramic block, also referred to
as a slider, that is aerodynamically designed so that it flies over the disc. The
slider is passed over the disc in a transducing relationship with the disc. Most
sliders have an air-bearing surface ("ABS") which includes rails and a cavity between
the rails. When the disc rotates, air is dragged between the rails and the disc
surface causing pressure, which forces the head away from the disc. At the same
time, the air rushing past the cavity or depression in the air bearing surface
produces a negative pressure area. The negative pressure or suction counteracts
the pressure produced at the rails. The slider is also attached to a load spring
which produces a force on the slider directed toward the disc surface. The various
forces equilibrate so the slider flies over the surface of the disc at a particular
desired fly height. The fly height is the distance between the disc surface and
the transducing head, which is typically the thickness of the air lubrication film.
This film eliminates the friction and resulting wear that would occur if the transducing
head and disc were in mechanical contact during disc rotation. In some disc drives,
the slider passes through a layer of lubricant rather than flying over the surface
of the disc.
Information representative of data is stored on the surface of the storage
disc. Disc drive systems read and write information stored on tracks on storage
discs. Transducers, in the form of read/write heads attached to the sliders, located
on both sides of the storage disc, read and write information on the storage discs
when the transducers are accurately positioned over one of the designated tracks
on the surface of the storage disc. The transducer is also said to be moved to
a target track. As the storage disc spins and the read/write head is accurately
positioned above a target track, the read/write head can store data onto a track
by writing information representative of data onto the storage disc. Similarly,
reading data on a storage disc is accomplished by positioning the read/write head
above a target track and reading the stored material on the storage disc. To write
on or read from different tracks, the read/write head is moved radially across
the tracks to a selected target track.
The methods for positioning the transducers can generally be grouped into two
categories. Disc drives with linear actuators move the transducer linearly generally
along a radial line to position the transducers over the various tracks on the
information storage disc. Disc drives also have rotary actuators which are mounted
to the base of the disc drive for arcuate movement of the transducers across the
tracks of the information storage disc. Rotary actuators position transducers by
rotationally moving them to a specified location on an information recording disc.
A rotary actuator positions the transducer quickly and precisely.
The actuator is rotatably attached to a shaft via a bearing cartridge which generally
includes one or more sets of ball bearings. The shaft is attached to the base and
may be attached to the top cover of the disc drive. A yoke is attached to the actuator
and is positioned at one end of the actuator. The voice coil is attached to the
yoke at one end of the rotary actuator. The voice coil is part of a voice coil
motor which is used to rotate the actuator and the attached transducer or transducers.
A set of permanent magnets is attached to the base and cover of the disc drive.
The voice coil motor which drives the rotary actuator comprises the voice coil
and the permanent magnet. The voice coil is attached to the rotary actuator and
the permanent magnet is fixed on the base. A top plate and a bottom plate are generally
used to attach the set of permanent magnets of the voice coil motor to the base.
The top plate and the bottom plate also direct the flux of the set of permanent
magnets. Since the voice coil sandwiched between the set of permanent magnets and
top plate and bottom plate which produces a magnetic field, electricity can be
applied to the voice coil to drive it so as to position the transducers at a target track.
One problem associated with disc drives is that the actuator assembly may resonate
or vibrate at certain frequencies which in turn causes the transducer within the
slider to move off-track. In other words, if there is even a slight vibration,
the slider may move away from the center of a track during a track following operation.
If the vibration is too large, the transducer continuously crosses the track to
be followed and little if any information can be read. Writing can not be accomplished
since there is a risk, at these times, that the transducer may be positioned over
another adjacent track and attempting to write may result in overwriting other
data that is necessary. The source of vibration may be the natural resonance of
an actuator assembly or may be due to other influences. One of these influences
is airflow generated by the rotating discs. The airflow generated by the rotating
disc or discs (also referred to as windage) excites head suspensions which in turn
cause the slider and transducers to vibrate. The vibration causes run-out which
is off-track motion. Of course as the density of tracks is increased, run-out due
to smaller vibrations becomes more critical.
What is needed is a disc drive that reduces vibration of the suspension and
attached transducer and slider resulting from airflow between the spinning discs
in a disc drive. What is also needed is a disc drive in which there is less off-track
motion or run-out. There is a constant need for a disc drive which has additional
capacity as well as increased reliability without an appreciable rise in the error
rate. There is also a need for methods and apparatus to reduce vibrations in the
suspension and attached slider and transducer.
SUMMARY OF THE INVENTION
Embodiments of the present invention are directed to providing an air
stream conditioning apparatus for a disc drive for damping the aerodynamic excitation
of an air stream or fluid flow on disc drive components. The disc drive typically
has an enclosure supporting a rotating disc and moveably supporting an actuator
having a distal end moving a data transfer element in a data transfer relationship
with a data storage surface of the data disc. In one aspect of the present invention
the flow conditioning apparatus comprises one or more first extensions pivotable
with respect to one or more second extensions. The flow conditioning apparatus
is supportable downstream of the actuator with respect to the flow currents. The
flow conditioning apparatus provides a second extension extending substantially
radially from an outer edge of the disc to an inner edge of the disc, adjacent
the disc surface. Embodiments of the present invention provides for the flow conditioning
apparatus to be changeable between a compact configuration and an operational configuration.
In another aspect of the invention, the flow conditioning apparatus includes a
shroud surface substantially transverse to the disc surface, at a far side of the
first extension. The first extension may include flat surfaces substantially coextensive
with the disc surfaces, or may integrate ramps for lifting the sliders away from
the disc surfaces.
Embodiments of the present invention provide for a way to reduce the
pressure difference across the actuator and decelerate the fluid flow impinging
on the actuaton. In addition, high frequency fluid flow disturbances can be redistributed
outside the servo bandwidth where the servo capability of the disc drive is better
equipped to effectively deal with the disturbance. The present invention therefore
provides the advantage of reducing windage induced non-repeatable run-out.
These and various other features as well as advantages which characterize the
present invention will be apparent upon reading of the following detailed description
and review of the associated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a disc drive in which several discs have been
removed to show an actuator and a flow conditioning apparatus according to one
embodiment of the present invention.
FIG. 2 is an isometric view of the flow conditioning apparatus in an unfolded
or operational configuration.
FIG. 3 is an isometric view of the flow conditioning apparatus in a folded or
compact configuration.
FIG. 4 is a flow chart showing a process for assembling the flow conditioning
apparatus in a disc drive.
FIG. 5 is a top view of the disc drive of FIG. 1.
FIG. 6 is a top view of a disc drive with a flow conditioning apparatus having
a shroud.
FIG. 7 is a side view of a flow conditioning apparatus according to another
embodiment of the present invention.
FIG. 8 illustrates a side view of the flow conditioning apparatus with an alternative
mounting feature.
FIG. 9 is an enlarged view showing features for positively positioning the flow
conditioning apparatus of FIG. 7 in the operational configuration.
FIG. 10 is an isometric view of a flow conditioning apparatus with an integrated ramp.
FIG. 11 is a top view showing the flow conditioning apparatus of FIG. 10 assembled
in a disc drive.
FIG. 12 is a flow chart illustrating a method of assembling the flow conditioning
apparatus of FIG. 10 to a disc drive.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is an isometric view of a disc drive
100 according to one embodiment
of the present invention. The disc drive
100 includes a base plate or base
102, and a cover
104. The base
102 and cover
104 form
a disc drive enclosure. Mounted to the base
102 is a spindle motor
106
to which several discs
110 are secured. Each disc
110 is generally
annular in shape, with an inner edge
112 and an outer edge
114 circumscribing
two opposing disc surfaces
116 (of which only one is visible in the drawing)
to which data can be stored for later retrieval. The base
102 provides a
cavity or room for the discs
110 to be seated in a substantially coaxial
arrangement, with an inner wall
118 of the base running around the outer
edges
114 of the discs
110, substantially transverse to the disc
surfaces
116.
In the drawing, several of the discs
110 have been removed to provide a
clearer illustration of an actuator assembly
120 that is pivotably mounted
to the base. On one side of the pivot
121, the actuator assembly
120
includes a plurality of arms
122 to which are attached load beams or suspensions
124. At the end of each suspension
124 is a slider
126 that
carries the read/write devices (designated generally by
128). The present
invention is equally applicable to sliders having different types of read/write
devices, such as what is generally referred to as transducers, magneto resistive
heads or giant magneto resistive heads. On another side of the pivot, the actuator
assembly
120 extends to support a voice coil
130 next to one or more
magnets
132 fixed relative to the base
102. When energized, resultant
electromagnetic forces on the voice coil
130 causes the actuator assembly
120 to rotate about the pivot
121, thereby bringing the read/write
devices into various radial locations relative to the disc surfaces
116.
It can be seen that, with the spindle motor
106 rotating the discs
110,
for example, in a direction indicated by arrow
140, and the actuator assembly
120 moving the read/write heads
128 in an arcuate path, as indicated
by arrow
142, across the disc surfaces
116, various locations on
the disc surfaces
116 can be accessed by the read/write heads for data recordation
or retrieval.
As the discs
110 are rotated, fluid or air adjacent to the disc surfaces
110 is also brought into motion, generating air streams or flow currents
in the disc drive enclosure. A flow conditioning apparatus
300 is provided
adjacent the discs
110 to modify or improve the flow behavior and characteristics
of the flow currents, as well as to exploit the flow currents to improve the overall
performance of the disc drive. The flow conditioning apparatus
300 includes
a set of fins or first extensions
310 pivotable with respect to a set of
vanes or second extensions
330.
Referring to FIG. 2, one embodiment of the flow conditioning apparatus
300 will be described in more detail. The flow conditioning apparatus
300
includes a set of first extensions
310, a pivot
320, and a set of
second extensions
330. Each first extension
310 can be generally
described as having a proximal end
312 and a distal end
314 relative
to the pivot
320.
From the proximal end
312 to the distal end
314, the first extension
310 includes two opposing flat surfaces
316 (of which only one is
visible in the drawing). The first extension
310 is configured such that,
in assembly, the flat surfaces
316 are substantially parallel to the disc
surfaces
116, as shown in FIG. 1. The first extension
310 has a near
side
318 running substantially from the proximal end
312 to the distal
end
314. In assembly, the near side
318 will be arranged next to
the outer edge
114 of a disc
110. In this embodiment, the near side
318 is slightly curved to follow the curvature of the outer edge
114
of the disc
110. Optionally, as illustrated here, the flat surface
316
is of variable width along the length of the first extension
310, with an
intermediate portion
313 that is wider than either the proximal end
312
or the distal end
314. The first extensions
310 are formed to be
of fixed spatial relation to one another, and are unitary with a first joint portion
322. The first extensions
310 may have the same thickness or substantially
the same thickness as the discs
110. The number of first extensions
310
in the flow conditioning apparatus
300 preferably equals the number of discs
110 in the disc drive
100. For example, if the disc drive configuration
calls for only one disc
110, the flow conditioning apparatus
300
may be formed with only one first extension
310. The first extensions
310
change the boundary conditions at the outer edges
114 of the discs
110
when assembled in close proximity to the discs, and essentially reduce turbulent
flow conditions at or off the outer edges
114 of the discs.
Continuing with FIG. 2, the flow conditioning apparatus includes a set
of second extensions
330, each of which are in fixed spatial relation to
one another, and are unitary with a second joint portion
324. In this particular
embodiment, the first joint portion
322 is substantially annular in shape,
and designed to be located co-axially with the second joint portion
324
which is also substantially annular in shape. A fastener
326 is threaded
through the first joint portion
322 and the second joint portion
324
to provide the pivot
320. The fastener
322 may serve an additional
function of engaging an appropriate receiver at the base
102, such as a
threaded hole, and thereby be used for securing the flow conditioning apparatus
300 to the base
102. Variations to the pivot
320 may be made
to allow for free, stepped or controlled rotation of the second extensions
330
relative to the first extensions
310.
FIG. 2 shows the flow conditioning apparatus
300 in an unfolded or operational
configuration
302 where the second extensions
330 are angularly displaced
from the first extensions
310. In one application, such as that shown in
FIG. 1, while the first extensions
310 are located alongside the outer edges
114 of the discs
110 in a generally circumferential orientation,
the second extensions
330 are directed in a generally radial orientation
such that the second extensions
330 extend from the outer edges
114
toward the inner edges
112 of the discs. Alternatively, the second extensions
330 may be oriented such that the second extensions
330 and the first
extensions
310 define an obtuse angle of displacement. In the operational
configuration
302, the second extensions
330 may be positioned above
the top-most disc
110 as well as between each of the discs
110. The
number of second extensions
330 is generally one more than the number of
discs
110 in the disc drive
100. Alternatively, the flow conditioning
apparatus
300 may have only one second extension
330 that is adjacent
the only disc surface
116 intended for data storage. The second extensions
330 are shaped to hinder flow currents that are generated by the spinning
discs
110. Each second extension
330 therefore presents a leading
side
332 to the on-coming flow currents, and a trailing side
334
(FIG. 2). Optionally, the leading side
332 may be a curved surface so that,
in assembly, the slider
126 will be generally the same distance away from
the leading side
332 for various radial positions of the slider
126.
Alternatively, the leading side
332 may be a substantially planar surface
so that the slider
126 will be nearer the leading side
332 the nearer
the slider is to the outer edges
114 of the discs
110.
FIG. 3 shows the flow conditioning apparatus
300 in a folded or compact
configuration
304 where the second extensions
330 and the first extensions
310 are rotated relative to each other until a compact shape for the flow
conditioning apparatus is achieved. In the compact configuration
304, the
second extensions
330 and the first extensions
310 substantially
overlap or are interleaved to form alternating layers of second extensions
330
and first extensions
310. Abutment features
340,
342 may be
provided to limit the extent of rotation of the second extensions
330 relative
to the first extensions
310. Features may be included to provide access
to the second extensions
330 when the flow conditioning apparatus
300
is in the compact configuration
304 so as to facilitate the change from
the compact configuration
304 to the operational configuration
302.
In this example, the first extensions
310 are shaped with notches or cavities
317 that expose the second extensions
330. Alternatively, the top-most
second extension
330 may be arranged above the top-most first extension
310, and can thus be easily accessed and pushed out from the compact configuration
304 to the operational configuration
302.
Without the made-for-manufacturing advantages provided by the present invention,
it would have been more difficult to assemble a part or a sub-assembly that is
intended to interleave the discs
110. More room on the base
102 would
have been required, and greater care would have been required to ensure that the
discs
110 are not injured in the course of assembly.
With the present invention, however, the compact configuration
304 allows
the flow conditioning apparatus
300 to be more easily installed while demanding
much less room for installation. In an exemplary assembly process
400 illustrated
by the flow chart of FIG. 4, the spindle motor
106 and discs
110
are assembled with the base
102 of the disc drive
100 (step
402).
The actuator assembly
120 is attached to the base
102 and merged
with the discs
110, that is, the sliders
126 are brought towards
the inner edges
112 of the discs
110 and parked at a landing zone
134 (step
404). The flow conditioning apparatus
300 in its
compact configuration
304 is then attached to a base
102 such that
the first extensions
310 are in a desired orientation (step
406).
Next, the second extensions
330 are pivoted with respect to the first extensions
310 until the flow conditioning apparatus
300 is in a desired operational
configuration
302 (step
408). Having a compact configuration
304
and an operational configuration
302 allows the flow conditioning apparatus
300 to be placed within the disc drive
100 with minimal change from
current manufacturing practices. In addition to other advantages, the present invention
reduces the likelihood of accidental damage to the discs
110 since each
second extension
330 approaches the discs
110 only after it is at
an elevation (with respect to the base
102) that is between discs, or above
or below a disc. The present invention also facilitates automated assembly, which
can be an important factor in overall cost efficiency in manufacture.
When the discs
110 are spinning, the flow conditioning apparatus
300
produces a high pressure region
502 next to the leading side
332
of the second extension
330, as schematically depicted in FIG. 5. On the
trailing side
334 of the second extension
330, a low pressure region
504 will be developed as the result of the flow conditioning apparatus
300.
The terms "high pressure" and "low pressure" are intended to be understood as being
relative to the pressure in a similar system that does not use a flow conditioning
apparatus
300 of the present invention. Further, the high pressure region
502 and the low pressure region
504 as drawn in FIG. 5 are merely
rough schematics and intended to aid understanding of the present invention, and
may differ for different embodiments of the present invention and for different
disc drive configurations in which the embodiment is implemented.
Alternatively described, the velocity of flow currents is reduced when
the flow currents come up against the leading side
332 of the second extensions
330. The second extensions
330 may be sized to substantially fill
the space between adjacent discs
110. In such a fashion, the slider
126
with its associated read/write devices
128 can be made to operate in a high
pressure region
502 created by the flow conditioning apparatus
300,
and thus operate within a stable region that is less prone to vibration resulting
from the flow currents. In addition, the velocity of flow currents within the disc
drive
100 and away from the flow conditioning apparatus
300 may be
reduced, thus stabilizing the slider
126 and the read/write devices
128.
Another way to consider the effect of the flow conditioning apparatus
300
would be that there is less energy in the flow currents and therefore less energy
to impart vibrations on various components of the disc drive
100. For example,
torque disturbances on the actuator assembly
120 are reduced. Accordingly,
the extent of vibration-induced run-out errors decreases, leading to an overall
improved performance of the disc drive
100.
The present invention may be further exploited to create an environment favorable
for efficient application of a breather filter
510. Air may sometimes enter
a disc drive. Rather than have unfiltered air enter the disc drive
100 and
contaminate its internal environment, a breather filter
510 is incorporated
with the disc drive
100 so that any air that enters the disc drive
100
is first filtered. The present invention provides for known locations where low
pressure regions
504 will develop, and thereby provide a desirable location
for the breather filter such that any air that enters the disc drive
100
would tend to enter through the breather filter
510 instead of through other
openings that may not provide for filtration. As shown FIG. 5, on the trailing
sides
334 of the second extensions
330, low pressure regions
504
develop when the discs
110 are spinning. A breather filter
510 may
be located so that its internal opening
512 opens to a low pressure region
504 that develops at the trailing side
334 of the second extension
330, as shown. Such a breather filter
510 may be located at the base
102 or at the cover
104 of the disc drive, and would include an external
opening
514 with a filter
516 interposed between the internal opening
512 and the external opening
514. Alternatively, the external opening
514 and the internal opening
512 may be the same hole, and the filter
516 may be located to cover the internal opening
512, and thereby
be in the position to filter any incoming air. Alternatively, the breather filter
510 may include an air channel
518 leading from the external opening
514 to the internal opening
512.
FIG. 6 is a top view of an alternative embodiment of the present invention,
showing the flow conditioning apparatus having at least one shroud surface
640.
As in the embodiment described above, the flow conditioning apparatus
600
includes one or more first extensions
610 pivotably connected to one or
more second extensions
630. In an operational configuration
602,
the second extensions
630 are angularly displaced from the first extensions
610. In a disc drive
100, the second extensions
630 are directed
generally radially with respect to the discs while the first extensions are disposed
to one side of the discs
110. The near side
618 of each first extension
610 is located next to the outer edges
114 of the discs
110.
Stretching along the far side
619 of each first extensions is a shroud surface
640 that is disposed substantially transverse to the disc surfaces
116.
The shroud surface
640 extends substantially from a proximal end
612
of the first extension
610 to a distal end
614 of the first extension
610. Between the near side
618 and the shroud surface
640,
the first extension provides two opposing and substantially flat surfaces
616
that, optionally, gradually increases in width. In other words, the shroud surface
640 leads away from the near side
618 as it extends away the proximal
end
612 towards the distal end
614. By closely fitting the shroud
surface
640 to the outer edge
114 of the disc
110 at the proximal
end
612, the flow currents are prevented from leaving the discs
110.
By increasingly widening the width of the flat surfaces
616, the shroud
640 channels the flow currents away from the slider
126 and the read/write
devices
128 before they are allowed to be expelled from the discs
110
in the direction indicated by arrow
642. The provision of the shroud
640
encourages laminar flow currents and reduces aerodynamic excitation from turbulent
flow currents. Shrouding also minimizes the effects of shedding vortices at the
outer edges
114 of the discs
110 that may produce axial forces on
the discs
110. At the same time, shrouding reduces resistive drag on the
spinning discs
110, and thus reduces the power required to maintain the
discs
100 at a desired rotational speed.
The present invention may be implemented in a disc drive
100 where it
is desired to provide as extensive a shroud as practicable around the discs
110.
The flow conditioning apparatus
600 with the shroud
640 may therefore
be used to reduce the opening in the main shroud (provided by the inner wall
118
of the base
102) so that the break in the overall shroud is just wide enough
to provide minimal clearance for movement of the actuator assembly
120.
In an alternative embodiment of the present invention, as shown in the elevation
view of FIG. 7, the flow conditioning apparatus
700 includes second extensions
730 pivotally joined to first extensions
710, where the first extensions
are supported by a frame
770. The frame
770 is formed at the far
sides
719 of the first extensions
730 with one wall of the frame
providing a shroud surface
740 along the far sides
719. The frame
further provides a cavity within which a filter cartridge
772 may be received.
Optionally, the frame may be provided with one or more locating tabs
774
for alignment with corresponding apertures in the base
102. A spring
776
cantilevered from the frame
770 has an enlarged portion
778 for pressingly
engaging the cover
104 when the cover
104 is attached to the base
102. In such a manner, the flow conditioning apparatus
700 may be
assembled in the disc drive
100 without the need for threaded fasteners,
thereby improving the efficiency of the manufacturing process.
FIG. 8 illustrates a side view of the flow conditioning apparatus
700
with an alternative mounting feature. The pivot
720 that provide for rotation
of the second extensions
730 relative to the first extensions
710
includes a shaft
780. The shaft
780 can be provided with a longitudinal
opening that receives a boss
782 supported by or formed as part of the base
102. A tool feature
784 can be provided for releasably engaging an
assembly tool for rotating the shaft
780 so that the flow conditioning apparatus
700, while assembled in its compact configuration, may be easily set into
its operational configuration.
A number of design-for-manufacturability features can be provided, for example,
features that generally positively position the flow conditioning apparatus
700
in the compact configuration or in the operational configuration. FIG. 9 is an
enlarged view of a flow conditioning apparatus
700 according to one embodiment
of the present invention. The first extensions
710 and the second extensions
730 engage at a pivot
720. The second extensions
730 include
an extending portion
750 that engages a selected portion
752 of the
base
102 to prevent further rotation after the flow conditioning apparatus
700 has reached its operational configuration.
Another design-for-manufacturability feature provides for positively retaining
the flow conditioning apparatus
700 in the operational configuration. In
FIG. 9, for example, the flow conditioning apparatus
700 further includes
an extending spring member
760. The spring member
760 is formed with
a detent
761. The second extension
730 includes a tab
766
that is received within the detent
761 at the proximal end
712 of
the first extension
710. Rotation of the second extensions
730 towards
the operational configuration causes the tab
766 to engage and deflect the
spring member
760. In the operational configuration, tab
766 is retained
within the detent
761 as the spring member
760 returns to pressingly
engage against the tab
766.
In yet another embodiment of the present invention, the flow conditioning apparatus
800 includes an integrated ramp
880, as shown in FIG. 10. The first
extensions
810 include near sides
818 that are sloped away from the
discs so as to facilitate the lifting of the slider
126 or of an extension
from the suspension
124 or slider
126. The process
900 of
assembling the flow conditioning apparatus
800 to the disc drive
100
such as that shown in FIG. 11 may be described with reference to the flow chart
of FIG. 12. The flow conditioning apparatus
800 is mounted to the base
102,
after which the spindle motor
106 and the discs
110 are assembled
to the base
102 (steps
902,
904). The flow conditioning apparatus
800 is assembled in its compact configuration where the first extensions
810 and the second extensions
830 are substantially interleaved.
The second extensions are rotated with respect to the base
102 such that
they now interleave the discs
110 (step
906). The actuator assembly
120 is then mounted to the base
102 and merged with the ramp
880
(step
908). Alternatively, the order of assembling the flow conditioning
apparatus
800, the spindle motor
106 with the discs
110 and
the actuator assembly
120 may be rearranged. This flexibility is another
advantage particularly beneficial to the design of manufacturing assembly lines
provided by the present invention.
Referring again to FIG. 10, the flow conditioning apparatus
800
may alternatively include a post
882, a lower end of which is adapted to
fit an opening in the base
102. The engagement between the post
882
and the base
102 may be such that the flow conditioning apparatus
800
is pivotable relative to the base
102. At the pivot
820 between the
first extensions
810 and the second extensions
830, there may be
provided an opening
884 for receiving a fastener
886. The fastener
886 engages the base
102 after passing through the opening
884,
thereby securing the orientation of the first extensions
810 with respect
to the base
102.
Alternatively described, one embodiment of the present invention provides
a flow conditioning apparatus (such as
300,
600,
700,
800)
for use in a disc drive (such as
100). The flow conditioning apparatus (such
as
300,
600,
700,
800) has a first extension (such
as
310,
610,
710,
810) defining a first plane and a
second extension (such as
330,
630,
730,
830) pivotably
connected to the first extension. The second extension (such as
330,
630,
730,
830) is rotatable about an axis (such as
320,
620,
720,
820), in a second plane that is substantially parallel to the
first plane.
According to one embodiment, the flow conditioning apparatus (such as
300,
600,
700,
800) may have a plurality of the first extensions
(such as
310,
610,
710,
810) interleaved with a plurality
of the second extensions (such as
330,
630,
730,
830)
along the axis. The second extensions (such as
330,
630,
730,
830) may fit between the respective first extensions (such as
310,
610,
710,
810) when the flow conditioning apparatus (such
as
300,
600,
700,
800) is in a folded configuration,
and be positioned away from the first extensions (such as
310,
610,
710,
810) when the flow conditioning apparatus (such as
300,
600,
700,
800) is in an operational configuration (such as
302). There may be a lock to bias the second extensions (such as
330,
630,
730,
830) against the first extensions such that the
flow conditioning apparatus (such as
300,
600,
700,
800)
is retained in the operational configuration (such as
302). Optionally,
the second extension may have an arcuate edge (such as
332).
In another embodiment, the flow conditioning apparatus (such as
600) may
include a shroud (such as
640) that defines a plane substantially transverse
to the first plane, with the shroud (such as
640) running substantially
from a proximal end (such as
612) of the first extension (such as
610)
to a distal end (such as
614) of the first extension (such as
610).
Optionally, the first extension (such as
610) is wider at the distal end
(
614) than at the proximal end (such as
612).
In yet another embodiment, the flow conditioning apparatus (such as
800)
may further incorporate a ramp (such as
880).
According to one embodiment of the present invention, there is provided
a disc drive (such as
100) having a disc (such as
110) configured
for rotation such that fluid flow is generated by the disc (such as
110)
when in rotation, an actuator (such as
120) adjacent the disc (such as
110),
and a flow conditioning apparatus (such as
300,
600,
700,
800) located adjacent the disc (such as
110). The flow conditioning
apparatus (such as
300,
600,
700,
800) may be described
as having a first extension (such as
310,
610,
710,
810)
defining a first plane and a second extension (such as
330,
630,
730,
830) that is pivotably connected to the first extension (such
as
310,
610,
710,
810) for rotational movement about
an axis (such as
320,
620,
720,
820). The second extension
(such as
330,
630,
730,
830) is configured to be rotatable
in a second plane that is substantially parallel to the first plane. In the disc
drive (such as
100), the second extension (such as
330,
630,
730,
830) may be located downstream of the actuator (such as
120)
with respect to the fluid flow.
The disc drive (such as
100) may include a flow conditioning apparatus
(such as
300,
600,
700,
800) where the second extension
(such as
330,
630,
730,
830) extends substantially
radially from an outer radial portion (such as
114) of the disc (such as
110) to an inner radial portion (such as
112) of the disc (such as
110). Optionally, the second extension (such as
330,
630,
730,
830) is disposed substantially transverse to a distal end (such
as
126) of the actuator (such as
120). Optionally, the second extension
(such as
330,
630,
730,
830) has an arcuate leading
edge (such as
332) disposed in proximity to a distal end (such as
126)
of the actuator (such as
120).
In another embodiment, the disc drive (such as
100) is such that the first
extension (such as
310,
610,
710,
810) extends along
an outer edge (such as
114) of the disc (such as
110) in proximity
to the outer edge (such as
114).
Optionally, the first extension (such as
310,
610,
710,
810) is substantially coplanar with the disc (such as
110). The disc
(such as
110) may be described as including opposing disc surfaces (such
as
116), and the first extension (such as
310,
610) may have
opposing extension surfaces (such as
316,
616) substantially coextensive
with respective disc surfaces (such as
116).
In yet another embodiment, the disc drive (such as
100) includes a plurality
of the disc (such as
110) and a plurality of the second extension (such
as
330,
630,
730,
830). In an operational configuration
(such as
302), the second extensions (such as
330,
630,
730,
830) interleave the discs (such as
110). In a compact configuration
(such as
304), the second extensions (such as
330,
630,
730,
830) may interleave the first extensions (such as
310,
610,
710,
810). Optionally, the second extensions (such as
330,
630,
730,
830) fit between the respective first extensions
(such as
310,
610,
710,
810) when the flow conditioning
apparatus (such as
300,
600,
700,
800) is in a compact
configuration (such as
304), and are positioned away from the first extensions
(such as
310,
610,
710,
810) when the flow conditioning
apparatus (such as
300,
600,
700,
800) is in an operational
configuration (such as
302). The disc drive (such as
100) may further
include a lock (such as
750,
752,
760,
761,
766,
884,
886) to bias the second extensions (such as
330,
630,
730,
830) against the first extensions (such as
310,
610,
710,
810) such that the flow conditioning apparatus (such as
300,
600,
700,
800) is retained in the operational configuration
(such as
302).
The disc drive (such as
100) may include a flow conditioning apparatus
(such as
300,
600,
700,
800) that further has a shroud
(such as
640) defining a plane substantially transverse to the first plane,
with the shroud (such as
640) running substantially from a proximal end
(such as
612) of the first extension (such as
610) to a distal end
(such as
614) of the first extension (such as
610). The shroud (such
as
640) may be nearer the disc (such as
110) at the proximal end
(such as
612) than at the distal end (such as
614).
Optionally, the disc drive (such as
100) includes a flow conditioning
apparatus (such as
800) of which the first extension (such as
810)
further incorporates a ramp (such as
880) adapted to receive a distal end
(such as
126) of the actuator (such as
120).
In yet another embodiment, the disc drive (such as
100) may include a
flow
conditioning apparatus (such as
700) that further has a filter housing (such
as
770) connected to the first extension (such as
710).
It is to be understood that even though numerous characteristics and advantages
of various embodiments of the present 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
size and placement of the flow conditioning apparatus may vary while maintaining
substantially the same functionality without departing from the scope and spirit
of the present invention. In addition, although the embodiments described herein
are directed to an apparatus for use in a disc drive, it will be appreciated by
those skilled in the art that the teachings of the present invention can be applied
to other systems, like data storage test or certification systems, servo track
writers, or optical data storage systems, without departing from the scope and
spirit of the present invention.
*
